bibliography.bib

@Comment{
SPDX-FileCopyrightText: 2020 Wolfgang Traylor <wolfgang.traylor@senckenberg.de>

SPDX-License-Identifier: CC0-1.0
}

@article{adamczewski1998influence,
  title    = {The influence of fatness on the likelihood of early-winter pregnancy in muskoxen (Ovibos moschatus)},
  journal  = {Theriogenology},
  volume   = {50},
  number   = {4},
  pages    = {605--614},
  year     = {1998},
  issn     = {0093--691X},
  doi      = {https://doi.org/10.1016/S0093--691X(98)00165-4},
  url      = {http://www.sciencedirect.com/science/article/pii/S0093691X98001654},
  author   = {J. Z. Adamczewski and P. J. Fargey and B. Laarveld and A. Gunn and P. F. Flood},
  keywords = {muskox, reproduction, body condition, IGF-1},
  abstract = {Among wild ruminants, muskoxen have an exceptional ability to fatten, but their pregnancy rates are variable and often low. To test whether the likelihood of pregnancy in muskoxen is associated with exceptionally good body condition, we used logistic regression analysis with data from 32 pregnant and 18 nonpregnant muskoxen ≥ 1.5 yr of age shot in November (1989 to 1992) on Victoria Island in Arctic Canada. We assayed their serum for insulin-like growth factor-1 (IGF-1). All fatness and mass measures were positively related to the likelihood of pregnancy (P < 0.001), with the strongest associations for estimated total fat mass (80 % of outcomes predicted correctly) and kidney fat mass (77 %), and weaker models for body mass. Pregnancy was less likely to occur in lactating females than in nonlactating ones (P = 0.03). Although IGF-1 concentrations were higher (P = 0.001) in nonlactating females than in lactating ones (28.7 ± 1.7 vs. 22.5 ng/ml), no association with pregnancy was detected (P = 0.57). Fatness associated with a 50 % probability of pregnancy in muskoxen (22 % of ingesta-free body mass or 32 kg fat in females > 3.5 yr old) is much higher than in caribou and somewhat higher than in cattle, and this may partly account for the low calving rates often observed in this species.}
}

@book{agricultural_research_council1980nutrient,
  title     = {The Nutrient requirements of ruminant livestock: technical review},
  isbn      = {0-85198-459-2},
  publisher = {{CAB} Intl},
  author    = {Agricultural Research Council},
  year      = {1980}
}

@article{anderson2005broadscale,
  author   = {Anderson, Kristina J. and Jetz, Walter},
  title    = {The broad‐scale ecology of energy expenditure of endotherms},
  journal  = {Ecology Letters},
  volume   = {8},
  number   = {3},
  year     = {2005},
  pages    = {310--318},
  keywords = {Birds, day length, doubly labelled water, energetics, field metabolic rate, latitude, mammals, metabolic niche, net primary production, temperature},
  doi      = {10.1111/j.1461-0248.2005.00723.x},
  url      = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1461-0248.2005.00723.x},
  eprint   = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1461-0248.2005.00723.x},
  abstract = {Energy expenditure in animals scales allometrically with body mass, but residual variation is not well understood. We examine the existing data on field metabolic rates (FMR) in endotherms for the potential role of environmental conditions. Across latitude, mass‐corrected FMR of 248 bird and mammal populations fall between two constraint lines: a lower bound that increases towards the poles and is driven by environmental factors and an upper bound that is invariant with latitude and may represent physiological limitations. This triangular pattern can be explained statistically with a multipredictor model that combines environmental conditions and species biology (including phylogeny). Lower environmental temperature and longer day length increase FMR, while taxonomy and diet explain much of the remaining variation. Combined, these effects appear to form a diversity of ‘metabolic niches’ that overall decreases from the tropics to the poles. The potential of factors related to latitude acting as constraints on the ecology and evolution of metabolic strategies in endotherms is discussed.}
}

@article{armstrong2000energetics,
  author   = {Armstrong, Helen M and Robertson, Antony},
  title    = {Energetics of free-ranging large herbivores: when should costs affect foraging behaviour?},
  journal  = {Canadian Journal of Zoology},
  volume   = {78},
  number   = {9},
  pages    = {1604--1615},
  year     = {2000},
  doi      = {10.1139/z00-099},
  URL      = { https://doi.org/10.1139/z00-099 },
  eprint   = { https://doi.org/10.1139/z00-099 },
  abstract = {Published relationships were used to build a mathematical model that predicts the daily net energy balance of free-ranging domestic sheep (Ovis aries L.) grazing in the U.K. hills. Net energy balance was predicted for a plausible range of environmental conditions. The behaviour of the model suggested the following predictions. Locomotion will be a relatively unimportant energetic cost. Ambient temperature and rainfall alone will rarely affect energy expenditure, whereas wind will greatly increase energetic costs in winter. These are further increased, but to a relatively small extent, by any concurrent rainfall. Predictions of foraging behaviour based on maximisation of energy intake alone are likely to significantly overestimate dry matter intake from climatically exposed vegetation in winter. Where shelter is available, such models will also overestimate total intake in winter by not taking account of sheltering behaviour. This effect will be most pronounced when forage is of low digestibility or availability, wind speeds are high, or the level of coat insulation is low. Foraging models based instead on maximisation of net energy balance are likely to greatly improve predictions of the impact of large herbivores on vegetation and the mechanisms driving their population dynamics.}
}

@article{berger1992facilitation,
  author   = {Berger, Joel},
  title    = {Facilitation of Reproductive Synchrony by Gestation Adjustment in Gregarious Mammals: A New Hypothesis},
  journal  = {Ecology},
  volume   = {73},
  number   = {1},
  pages    = {323--329},
  doi      = {10.2307/1938743},
  url      = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.2307/1938743},
  eprint   = {https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.2307/1938743},
  abstract = {Among gregrious, plaental mammals, breeding synchrony usually occurs by adjustment of the timing of estrus, not births, and it has been suspected that the former process govern synchronized parturition. Gestation length data gathered on wild plains bison (Bison bison) over a 5—yr period demonstrate:(1) females in good body condition who were mated after the seasonal peak shortened gestation by °6 d, synchronizing births with other females; (2) no similar adjustments occurred among females in poor condition; and (3) those females that shortened gestation incurred a cost because their neonates were, on average, °20 kg lighter when 6 mo old. Reproductive synchrony may also be achieved by a less radical tactic; unmated females use olfactory cues to explore the status of other females prior to their own estrus but not after. These data suggest that there is adaptive variation in gestation length in bison cows in good condition and that assumptions about the constancy of gestation are unwarranted.},
  year     = {1992}
}

@article{birkett2001limitations,
  title   = {Limitations of conventional models and a conceptual framework for a nutrient flow representation of energy utilization by animals},
  volume  = {86},
  DOI     = {10.1079/BJN2001441},
  number  = {6},
  journal = {British Journal of Nutrition},
  author  = {Birkett, Stephen and de Lange, Kees},
  year    = {2001},
  pages   = {647--659}
}

@book{blaxter1989energy,
  title     = {Energy Metabolism in Animals and Man},
  pagetotal = {356},
  publisher = {{CUP} Archive},
  author    = {Blaxter, Kenneth},
  year      = {1989}
}

@article{bradbury1996relationship,
  ISSN     = {00129658, 19399170},
  URL      = {https://doi.org/10.2307/2265717},
  abstract = {The foraging of female Thomson's gazelles (Gazella thomsoni) on shortgrass plains was monitored over one annual cycle in southwestern Kenya. Sward dry green biomasses and protein densities were estimated regularly throughout the study site. Changes in protein densities with season and locale were strongly correlated with underlying changes in grass physiognomy: sward height and dry green bulk biomass density were particularly important and were found to vary inversely. The relationship between bite rates and underlying sward parameters varied with season: gazelle bite rates in the dry season were positively correlated with underlying dry green biomass and protein densities, as predicted by either the Process 1 or Process 2 foraging model of Spalinger and Hobbs. Nonlinear regressions of within-bout bite rates on these model equations significantly explained 21.8 and 23.7% of the dry season variance, respectively. In contrast, bite rates in the early wet season showed significant negative correlations with underlying protein densities: the fit of the within-bout bite rate data to Spalinger and Hobbs' Process 3 model explained 18.4% of the overall variation. The late wet season showed a flat (insignificant) relationship between bite rates and protein levels and was thus intermediate between early wet- and later dry-season patterns. Logistic regression of the type of correlation between bite rate and protein density (positive, flat, negative) on two principal components of grass physiognomy suggested that a component heavily weighting sward height was the major correlate of foraging process, whereas a second major component heavily weighting bulk density and other grass quality measures was less critical. At least during this single annual cycle, shorter swards were associated with Processes 1 or 2, whereas taller swards showed Process 3 foraging. One interpretation of these results is that sward height modulates bite mass, which in turn plays the major role in controlling foraging process. Whether the switching point remains the same in subsequent years or not, the results make it clear that the direction of the bite rate vs. foraging density relationship can change markedly with season, as predicted by the Spalinger and Hobbs models.},
  author   = {Jack W. Bradbury and Sandra L. Vehrencamp and Kenneth E. Clifton and Lisa M. Clifton},
  journal  = {Ecology},
  number   = {7},
  pages    = {2237--2255},
  title    = {The Relationship Between Bite Rate and Local Forage Abundance in Wild Thomson's Gazelles},
  volume   = {77},
  year     = {1996}
}

@article{bradley1980reexamination,
  title   = {A re-examination of the relationship between thermal conductance and body weight in mammals},
  journal = {Comparative Biochemistry and Physiology Part A: Physiology},
  volume  = {65},
  number  = {4},
  pages   = {465--476},
  year    = {1980},
  issn    = {0300-9629},
  doi     = {https://doi.org/10.1016/0300-9629(80)90060-2},
  url     = {http://www.sciencedirect.com/science/article/pii/0300962980900602},
  author  = {Bradley, Robert S and Deavers, Daniel R}
}

@article{bredon1963chemical,
  author    = {R. M. Bredon and J. Wilson},
  title     = {The Chemical Composition and Nutritive Value of Grasses from Semi-Arid Areas of Karamoja as Related to Ecology and Types of Soil},
  journal   = {East African Agricultural and Forestry Journal},
  volume    = {29},
  number    = {2},
  pages     = {134--142},
  year      = {1963},
  publisher = {Taylor \& Francis},
  doi       = {10.1080/00128325.1963.11661913},
  URL       = { http://www.tandfonline.com/doi/abs/10.1080/00128325.1963.11661913 },
  eprint    = { http://www.tandfonline.com/doi/pdf/10.1080/00128325.1963.11661913 }
}

@article{bronson1991energetic,
  author   = {Bronson, F. H. and Manning, Judith M.},
  title    = {The Energetic Regulation of Ovulation: A Realistic Role for Body Fat},
  journal  = {Biology of Reproduction},
  volume   = {44},
  number   = {6},
  pages    = {945--950},
  year     = {1991},
  month    = {06},
  abstract = {This review weighs the evidence for and against the hypothesis that ovulation is regulated by a critical amount of body fat. The evidence supporting this hypothesis is correlative, and most of it stems from observations made in humans. On balance, the evidence from human studies does not support the hypothesis, however, and the results of animal studies argue strongly against it. In the latter regard, a variety of experimental approaches have been tried in both adult and peripubertal females of several species, and the results almost uniformly show little relationship between fatness and ovulation. There is no doubt that ovulation can be regulated somehow in relation to whole-body energy balance and that fat stores are an important component of energy balance, but there is no reason to accord body fat a direct causal role in regulating ovulation.},
  issn     = {0006-3363},
  doi      = {10.1095/biolreprod44.6.945},
  url      = {https://doi.org/10.1095/biolreprod44.6.945},
  eprint   = {http://academic.oup.com/biolreprod/article-pdf/44/6/945/23258302/biolreprod0945.pdf},
}

@book{calder1996function,
  address   = {Mineola, NY},
  author    = {Calder, William A.},
  publisher = {Dover Publisher},
  edition   = {Corrected, slightly enlarged republication of the work first published by Harvard Univ. Press, Cambridge, Mass. 1984},
  isbn      = {0486691918},
  title     = {Size, function, and life history},
  year      = {1996}
}

@collection{canham2003models,
  editor    = {Canham, Charles D. and Cole, Jonathan J. and Lauenroth, William K.},
  author    = {Canham, Charles D. and Cole, Jonathan J. and Lauenroth, William K.},
  year      = {2003},
  title     = {Models in Ecosystem Science},
  isbn      = {0-691-09288-5},
  address   = {Princeton, New Jersey},
  publisher = {Princeton University Press}
}
https://hds.hebis.de/ubffm/Record/HEB11399558X

@article{chesson2000mechanisms,
  author   = { Peter Chesson},
  title    = {Mechanisms of Maintenance of Species Diversity},
  journal  = {Annual Review of Ecology and Systematics},
  volume   = {31},
  number   = {1},
  pages    = {343--366},
  year     = {2000},
  doi      = {10.1146/annurev.ecolsys.31.1.343},
  URL      = { https://doi.org/10.1146/annurev.ecolsys.31.1.343 },
  eprint   = { https://doi.org/10.1146/annurev.ecolsys.31.1.343 } ,
  abstract = { The focus of most ideas on diversity maintenance is species coexistence, which may be stable or unstable. Stable coexistence can be quantified by the long-term rates at which community members recover from low density. Quantification shows that coexistence mechanisms function in two major ways: They may be (a) equalizing because they tend to minimize average fitness differences between species, or (b) stabilizing because they tend to increase negative intraspecific interactions relative to negative interspecific interactions. Stabilizing mechanisms are essential for species coexistence and include traditional mechanisms such as resource partitioning and frequency-dependent predation, as well as mechanisms that depend on fluctuations in population densities and environmental factors in space and time. Equalizing mechanisms contribute to stable coexistence because they reduce large average fitness inequalities which might negate the effects of stabilizing mechanisms. Models of unstable coexitence, in which species diversity slowly decays over time, have focused almost exclusively on equalizing mechanisms. These models would be more robust if they also included stabilizing mechanisms, which arise in many and varied ways but need not be adequate for full stability of a system. Models of unstable coexistence invite a broader view of diversity maintenance incorporating species turnover. }
}

@article{clauss2007case,
  title    = {A case of non-scaling in mammalian physiology? Body size, digestive capacity, food intake, and ingesta passage in mammalian herbivores},
  author   = {Marcus Clauss and Angela Schwarm and Sylvia Ortmann and W. Jürgen Streich and Jürgen Hummel},
  journal  = {Comparative Biochemistry and Physiology Part A: Molecular \& Integrative Physiology},
  volume   = {148},
  number   = {2},
  pages    = {249--265},
  year     = {2007},
  issn     = {1095-6433},
  doi      = {https://doi.org/10.1016/j.cbpa.2007.05.024},
  url      = {http://www.sciencedirect.com/science/article/pii/S109564330701046X},
  keywords = {Herbivory, Digestive physiology, Digestive anatomy, Body size, Ingesta retention, Coprophagy, Grazer, Browser, Foregut fermenter, Ruminant, Hindgut fermenter},
  abstract = {As gut capacity is assumed to scale linearly to body mass (BM), and dry matter intake (DMI) to metabolic body weight (BM0.75), it has been proposed that ingesta mean retention time (MRT) should scale to BM0.25 in herbivorous mammals. We test these assumptions with the most comprehensive literature data collations (n = 74 species for gut capacity, n = 93 species for DMI and MRT) to date. For MRT, only data from studies was used during which DMI was also recorded. Gut capacity scaled to BM1.06. In spite of large differences in feeding regimes, absolute DMI (kg/d) scaled to BM0.76 across all species tested. Regardless of this allometry inherent in the dataset, there was only a very low allometric scaling of MRT with BM0.14 across all species. If species were divided according to the morphophysiological design of their digestive tract, there was non-significant scaling of MRT with BM0.04 in colon fermenters, BM0.08 in non-ruminant foregut fermenters, BM0.06 in browsing and BM0.04 in grazing ruminants. In contrast, MRT significantly scaled to BM0.24 (CI 0.16–0.33) in the caecum fermenters. The results suggest that below a certain body size, long MRTs cannot be achieved even though coprophagy is performed; this supports the assumption of a potential body size limitation for herbivory on the lower end of the body size range. However, above a 500 g-threshold, there is no indication of a substantial general increase of MRT with BM. We therefore consider ingesta retention in mammalian herbivores an example of a biological, time-dependent variable that can, on an interspecific level, be dissociated from a supposed obligatory allometric scaling by the morphophysiological design of the digestive tract. We propose that very large body size does not automatically imply a digestive advantage, because long MRTs do not seem to be a characteristic of very large species only. A comparison of the relative DMI (g/kg0.75) with MRT indicates that, on an interspecific level, higher intakes are correlated to shorter MRTs in caecum, colon and non-ruminant foregut fermenters; in contrast, no significant correlation between relative DMI and MRT is evident in ruminants.}
}

@article{cook2004effects,
  author   = {Cook, John G. and Johnson, Bruce K. and Cook, Rachel C. and Riggs, Robert A. and Delcurto, Tim and bryant, Larry D. and Irwin, Larry L.},
  title    = {Effects of summer–autumn nutrition and parturition date on reproduction and survival of elk},
  journal  = {Wildlife Monographs},
  volume   = {155},
  number   = {1},
  pages    = {1--61},
  keywords = {Cervus elaphus, digestible energy, dry-matter intake, elk, gestation, growth, habitat, lactation, nutrition, nutritional condition, Oregon, population dynamics, pregnancy, reproduction, survival},
  doi      = {10.2193/0084-0173(2004)155[1:EOSNAP]2.0.CO;2},
  url      = {https://wildlife.onlinelibrary.wiley.com/doi/abs/10.2193/0084-0173%282004%29155%5B1%3AEOSNAP%5D2.0.CO%3B2},
  eprint   = {https://wildlife.onlinelibrary.wiley.com/doi/pdf/10.2193/0084-0173%282004%29155%5B1%3AEOSNAP%5D2.0.CO%3B2},
  abstract = {Recent declines in numbers and juvenile recruitment in many elk (Cervus elaphus) herds in the western U.S. has sparked interest in factors that may cause these declines. Inadequate nutrition or delayed parturition, the latter of which may be caused by inadequate numbers of mature bulls (i.e., highly skewed sex ratios), may have separate or synergistic effects on population dynamics and productivity. We evaluated the implications of late parturition and summer-autumn nutrition on reproduction and survival of Rocky Mountain elk (C. e. nelsoni) using a captive herd of 57 cow elk. We induced early (Sep) and late breeding (Oct) and 3 levels of summer-autumn nutrition on the cows. Food was offered ad libitum at 3 levels of digestible energy (DE): high = 2.9-3.0 kcal of DE/g of diets, medium = 2.6-3.0 kcal/g, and low = 2.3-3.0 kcal/g. Within these ranges, DE content was gradually reduced from late June through early November to mimic seasonal changes in the wild. During summer and autumn, we measured calf growth; body mass, nutritional condition, and breeding dynamics of cows; and growth and pregnancy of yearlings. We also measured carry-over (i.e., time-lag) responses including over-winter calf and cow survival and parturition date and birth mass, as functions of previous summer-autumn nutrition and previous parturition date. Between autumn 1995 and spring 1998, we conducted 2 years of parturition-date, summer-autumn nutrition experiments, 2 winters of calf survival experiments, and 1 winter of cow survival experiments. Early birth provided calves with more time to grow before onset of winter. This “head-start” advantage was maintained through late autumn, but its magnitude was diluted in some instances due to faster growth of some late-born calves. Body mass, body fat, and timing and probability of conception by cows in autumn were little influenced by parturition date the previous spring. Summer-autumn nutrition significantly affected calves and their mothers. Growth of calves in the low and medium nutrition groups ceased by mid-September and late October. By December, calves in the high nutrition group were 40\% and 70\% heavier than calves in the medium and low groups, respectively. Cows in the high nutrition group accumulated about 75\% and 300\% more fat than cows in the medium and low groups by mid-October. Eighty percent of cows in the low nutrition group failed to conceive, and those in the medium group bred 10–14 days later than cows in the high group. Summer-autumn nutrition of calves influenced their probability of becoming pregnant as yearlings. Probability of pregnancy approached 100\% for those yearlings that had high summerautumn nutrition as calves and yearlings, despite near starvation their first winter of life. Winter survival of calves was related to their size at the onset of winter. Smaller calves lost more body mass daily than did large calves, and thus they survived fewer days through winter. Summer-autumn nutrition largely determined calf body size at the start of winter and, consequently, determined the proportion of winter survived. Survival of cows over winter was as related to body fat at the onset of winter as it was to nutrition during winter. Carry-over effects of summer-autumn nutrition and parturition date on birth characteristics the following spring were minor. We detected no significant carry-over effect of summer-autumn nutrition or autumn condition on birth mass, although reduced condition in autumn delayed subsequent parturition date. Extent of body fat depletion in cows during the winter-survival experiments in 1998 accounted for 45\% of the variation in parturition date. Ninety percent depletion delayed parturition an average of 34 days. Delayed parturition, of a magnitude expected due to highly skewed sex ratios (3 weeks under extreme conditions), probably has only a weak influence on vital rates of free-ranging elk. In contrast, fat accretion and probability of pregnancy of cows, and growth and overwinter survival of calves, were sensitive to small (10–20\%) differences in DE content of food. Digestible energy levels of our 2 lower nutrition levels reflect DE ranges reported for large ungulate herds during summer and autumn in western North America. Thus, our data suggest that limiting effects of summer-autumn nutrition on populations may be greater than often assumed, perhaps greater than those during winter in some ecosystems, and consequently indicate a need for greater understanding of nutrition's influence on population dynamics and how this influence varies across space and time. To enhance future research, we present animal- and vegetation-based guidelines for evaluating nutritional influences on elk populations.},
  year     = {2004}
}

@report{corbett1990feeding,
  organization = {Standing Committee on Agriculture (SCA)},
  author       = {Corbett, J.L. and Freer, M. and Hennessy, D.W. and Hodge, R.W. and Kellaway, R.C. and McMeniman, N.P. and Nolan, J.V.},
  title        = {Feeding standards for Australian livestock: Ruminants},
  isbn         = {0643043144},
  publisher    = {CSIRO Publications},
  location     = {Victoria, N.S.W., Australia},
  year         = {1990},
  url          = {http://hdl.handle.net/102.100.100/256672}
}
https://books.google.se/books?id=pat_ou8Fh1cC

@article{cuyler2004rain,
  title    = {Rain more important than windchill for insulation loss in Svalbard reindeer fur},
  journal  = {Rangifer},
  year     = {2004},
  volume   = {24},
  number   = {1},
  pages    = {7-14},
  issn     = {0333-256X},
  url      = {https://www.ingentaconnect.com/content/doaj/0333256x/2004/00000024/00000001/art00002},
  doi      = {doi:10.7557/2.24.1.262},
  author   = {Christine Cuyler and Nils A. \Oritsland},
  abstract = {Heat transfer through dry and wet Svalbard reindeer (Rangifer tarandus platyrhynchus) summer and winter midback fur samples was studied in a wind tunnel. A light wetting water spray simulated heavy fog, mist or light rain, while heavy soaking simulated heavy rain. Wind velocities ranged from 0 to 10 m.s-1. Calf fur samples were from June, August and March. Adult fur samples were females from August and March. There was no evidence for increased heat loss from lightly wet fur relative to dry fur. Calm air conductance decreased for calf fur (P&rsquo;s &lt; 0.05). Adult fur also decreased, however, the difference was not significant (P &gt; 0.05). Further, wind coefficients and regressions for lightly wet fur were similar or below those for dry fur. A thin water film forming on the fur surface may have caused this. It is unlikely that a light rain, fog or mist would cause increased heat loss for Svalbard reindeer, and no increase of metabolic heat production would be needed to maintain thermoregulation. Only the simulated heavy rain dramatically raised heat loss from the fur samples examined regardless of age or season, e.g., heavy soaking increased calm air conductance for all furs (P&rsquo;s &lt; 0.05). This was likely due to the addition of evaporative heat loss from the fur surface and a reduction in the amount of trapped air within the fur. Windchill was of minor importance, since wind coefficients were generally close to zero, meaning increasing wind velocity only marginally raised heat loss even with the added effect of evaporative heat loss. Rain would cause greater insulation loss than increasing wind velocity in Svalbard reindeer of all ages, with the exception of calves under one month old, which could experience dramatic insulation loss from a combination of heavy rain and windchill. Dry or wet, Svalbard reindeer fur appears to provide better insulation than fur of others of their species.},
}

@collection{danell2006large,
  location  = {Cambridge [u.a.]},
  title     = {Large herbivore ecology, ecosystem dynamics and conservation},
  isbn      = {978-0-521-83005-8},
  series    = {Conservation Biology},
  pagetotal = {xvi+506},
  number    = {11},
  publisher = {Cambridge University Press},
  editor    = {Danell, Kjell and Bergstr{\"o}m, Roger and Duncan, Patrick and Pastor, John},
  author    = {Danell, Kjell and Bergstr{\"o}m, Roger and Duncan, Patrick and Pastor, John},
  year      = {2006}
}
https://books.google.de/books?id=HuYFLQ31m8YC

@article{depperschmidt1987body,
  ISSN      = {0022541X, 19372817},
  URL       = {https://doi.org/10.2307/3801287},
  abstract  = {Total body composition, kidney fat indices, and bone marrow levels were obtained from 13 female pronghorns (Antilocapra americana) that starved in Wyoming during winter 1983-84. Mean values for total body water, fat, protein, and ash were 70.8, 2.1, 19.9, and 7.9%, respectively. Left and right kidney fat indices averaged 6.9 and 7.6%, respectively, and mean bone marrow fat was 0.6%. Although indices for bone marrow fat and kidney fat reflect total body fat levels, they are insensitive to small changes when fat levels approach depletion.},
  author    = {Jack D. Depperschmidt and Stephen C. Torbit and A. William Alldredge and Robert D. Deblinger},
  journal   = {The Journal of Wildlife Management},
  number    = {3},
  pages     = {675--678},
  publisher = {[Wiley, Wildlife Society]},
  title     = {Body Condition Indices for Starved Pronghorns},
  volume    = {51},
  year      = {1987}
}

@article{dirnagl2020preregistration,
  author   = {Dirnagl, Ulrich},
  journal  = {PLOS Biology},
  title    = {Preregistration of exploratory research: Learning from the golden age of discovery},
  year     = {2020},
  month    = {03},
  volume   = {18},
  url      = {https://doi.org/10.1371/journal.pbio.3000690},
  pages    = {1--6},
  abstract = {Pre-registration and registered reports of research that develops theories and hypotheses has the potential to reduce waste and increase the value of biomedical research. This Perspective argues that journals and scientists should develop and experiment with pre-registration formats for discovery research.},
  number   = {3},
  doi      = {10.1371/journal.pbio.3000690}
}

@article{doughty2013legacy,
  author    = {Doughty, Christopher E. and Wolf, Adam and Malhi, Yadvinder},
  title     = {The legacy of the Pleistocene megafauna extinctions on nutrient availability in Amazonia},
  journal   = {Nature Geoscience},
  year      = {2013},
  month     = {08},
  publisher = {Nature Publishing Group},
  volume    = {6},
  pages     = {761--764},
  url       = {http://dx.doi.org/10.1038/ngeo1895}
}

@article{ferrell2008asas,
  author   = {Ferrell, C. L. and Oltjen, J. W.},
  title    = {ASAS CENTENNIAL PAPER: Net energy systems for beef cattle—Concepts, application, and future models},
  journal  = {Journal of Animal Science},
  volume   = {86},
  number   = {10},
  pages    = {2779--2794},
  year     = {2008},
  month    = {10},
  abstract = {Development of nutritional energetics can be traced to the 1400s. Lavoisier established relationships among O2 use, CO2 production and heat production in the late 1700s, and the laws of thermodynamics and law of Hess were discovered during the 1840s. Those discoveries established the fundamental bases for nutritional energetics and enabled the fundamental entity ME = retained energy + heat energy to be established. Objectives became: 1) to establish relationships between gas exchange and heat energy, 2) to devise bases for evaluation of foods that could be related to energy expenditures, and 3) to establish causes of energy expenditures. From these endeavors, the basic concepts of energy partitioning by animals were developed, ultimately resulting in the development of feeding systems based on NE concepts. The California Net Energy System, developed for finishing beef cattle, was the first to be based on retained energy as determined by comparative slaughter and the first to use 2 NE values (NEm and NEg) to describe feed and animal requirements. The system has been broadened conceptually to encompass life cycle energy requirements of beef cattle and modified by the inclusion of numerous adjustments to address factors known to affect energy requirements and value of feed to meet those needs. The current NE system remains useful but is empirical and static in nature and thus fails to capture the dynamics of energy utilization by diverse animals as they respond to changing environmental conditions. Consequently, efforts were initiated to develop dynamic simulation models that captured the underlying biology and thus were sensitive to variable genetic and environmental conditions. Development of a series of models has been described to show examples of the conceptual evolution of dynamic, mechanistic models and their applications. Generally with each new system, advances in prediction accuracy came about by adding new terms to conceptually validated models. However, complexity of input requirements often limits general use of these larger models. Expert systems may be utilized to provide many of the additional inputs needed for application of the more complex models. Additional information available from these systems is expected to result in an everincreasing range of application. These systems are expected to have increased generality and the capability to be integrated with other models to allow economic evaluation. This will eventually allow users to compute solutions that allow development of optimal production strategies.},
  issn     = {0021-8812},
  doi      = {10.2527/jas.2008-0954},
  url      = {https://doi.org/10.2527/jas.2008-0954},
  eprint   = {http://oup.prod.sis.lan/jas/article-pdf/86/10/2779/23669557/2779.pdf},
}

@thesis{foose1982trophic,
  title       = {Trophic strategies of ruminant versus nonruminant ungulates},
  institution = {University of Chicago},
  type        = {phdthesis},
  author      = {Foose, Thomas J.},
  year        = {1982}
}

@article{fortin2002temporal,
  title     = {The Temporal Scale of Foraging Decisions in Bison},
  ISSN      = {00129658, 19399170},
  URL       = {https://doi.org/10.2307/3071906},
  abstract  = {Assessing the temporal scale under which gain is maximized is critical for the understanding of diet choice by animals. Classical foraging theory assumes that animals maximize long-term rates. Few studies have considered several temporal scales concurrently, however, weakening tests of rate-maximizing models. We used contingency models based on maximization of short-term vs. long-term energy intake by bison (Bison bison). Model predictions were tested against field observations conducted during six periods of 1998: two periods in the winter, one in the spring, and three in the summer. During most of the year, foraging characteristics and plant attributes suggested that intake rate of bison should be limited by ingestion time over short periods of time, and by digestive constraints over long periods of time. Diet predictions varied across temporal scales for four of the six sampling periods. Selecting Agropyron spp., rather than Carex atherodes, during these periods would result in an increase of daily energy intake by as much as 15 565 kJ (i.e., 7.4% of daily gains) but would necessitate a longer daily foraging time. We observed, instead, that bison preferred C. atherodes to Agropyron spp., suggesting that patterns of diet selection by bison were more consistent with maximization of short-term than of long-term energy intake. We thus provide some evidence that, contrary to established principles of classic optimality models, the foraging decisions of bison reduce potential long-term gains by maximizing short-term gains.},
  author    = {Daniel Fortin and John M. Fryxell and Régis Pilote},
  journal   = {Ecology},
  number    = {4},
  pages     = {970--982},
  volume    = {83},
  year      = {2002}
}

@article{fortin2004multitasking,
  author   = {Fortin, Daniel and Boyce, Mark S. and Merrill, Evelyn H.},
  title    = {Multi-Tasking by Mammalian Herbivores: Overlapping Processes during Foraging},
  journal  = {Ecology},
  volume   = {85},
  number   = {8},
  pages    = {2312--2322},
  keywords = {competition, food intake rate, foraging constraints, foraging models, functional response of herbivores, group size, mammalian herbivores, multi-tasking, optimal vigilance, overlap between foraging processes, spare time},
  doi      = {10.1890/03-0485},
  url      = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/03-0485},
  eprint   = {https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1890/03-0485},
  abstract = {Mammalian herbivores can carry out multiple tasks without interrupting food processing, but this possibility is not considered in existing foraging models. We develop a mechanistic functional response to account for herbivores' ability to search for their next food bite and walk away from competitors while chewing vegetation. We demonstrate how the possibility of multi-tasking can buffer intake rate from competition and vigilance. The functional response of herbivores can be density independent until a threshold of competitors is reached in the food patch, and only then does it become density dependent. Herbivores also should be capable of maintaining food intake rate, despite important resource depletion in the foraging patch. The possibility of animal movements during food processing offers herbivores opportunities for cost-free vigilance. When individuals find their next bite before they have finished chewing the current bite, the remaining chewing time becomes “spare time” that could be spent in vigilance without reducing food intake rate. Modeling of optimal vigilance demonstrates that such cost-free vigilance might importantly alter expected patterns of scanning by mammalian herbivores. Assuming that interference increases with competitor density, spare time available for scanning should decrease as the number of herbivores in a food patch increases. Foraging constraints on food intake thus can provide a mechanistic explanation for the commonly observed decline in herbivore vigilance with increasing group size.},
  year     = {2004}
}

@proceedings{fowler2004dynamics,
  editor    = {Fowler, Charles W. and Smith, Tim D.},
  year      = {2004},
  title     = {Dynamics of Large Mammal Populations},
  publisher = {Blackburn Press},
  location  = {Caldwell, New Jersey},
  ISBN      = {1-930665-27-X},
  note      = {Reprint of first edition from 1981},
  eventdate = {1978},
  venue     = {Logan, Utah},
  origdate  = {1981}
}

@article{friggens2010nutritional,
  title     = {Nutritional sub-fertility in the dairy cow: towards improved reproductive management through a better biological understanding},
  volume    = {4},
  DOI       = {10.1017/S1751731109991601},
  number    = {7},
  journal   = {Animal},
  author    = {Friggens, N. C. and Disenhaus, C. and Petit, H. V.},
  year      = {2010},
  pages     = {1197–1213},
  abstract  = { There has been a significant decline in the reproductive performance of dairy cattle in recent decades. Cows, take longer time to return to the oestrus after calving, have poorer conception rates, and show fewer signs of oestrus. Achieving good reproductive performance is an increasing challenge for the dairy producer. In this study we focus on understanding the overall biological phenomena associated with nutritional sub-fertility rather than the underlying multiplicity of physiological interactions (already described in a number of recent studies). These phenomena are important because they represent the natural adaptations of the animal for dealing with variations in the nutritional environment. They can also be used to monitor and modulate reproductive performance on-farm. There is an underlying trade-off between two aspects of reproduction: investment in the viability of the current calf and investment in future offspring. As the investment in, and viability of, the current calf is related to maternal milk production, we can expect that level of milk production per se has effects on subsequent reproductive performance (investment in future offspring). Lactating cows have a lower proportion of viable embryos, which are of poorer quality, than do non-lactating cows. The same applies to high- compared to medium-genetic merit cows. Another important biological property is the adaptive use of body reserves in support of reproduction. Orchestrated endocrine changes in pregnancy and lactation facilitate the deposition of body lipid during pregnancy and mobilisation in early lactation. When the cow fails to accumulate the reserves she needs to safeguard reproduction she delays committing to further reproductive investment. But how does the cow ‘know’ that she is failing in energy terms? We argue that the cow does this by ‘monitoring’ both the body fat mobilisation and body fatness. Excessive body fat mobilisation indicates that current conditions are worse than expected. Body fatness indicates the future ability of the cow to safeguard her reproductive investment is compromised. Both delay further reproductive commitment. The relationship between reproductive performance and; milk production as an index of maternal investment, body fatness as an index of ability to safeguard reproductive investment, and body fat mobilisation as an index of the current nutritional environment – are examined. Nutritional strategies that seek to modulate body mobilisation and the endocrine environment by use of glucogenic and lipogenic diets, and the use of in-line progesterone profiles to monitor reproductive status are then discussed in this biological context. }
}

@article{frisch1974menstrual,
  author    = {Frisch, Rose E. and McArthur, Janet W.},
  title     = {Menstrual Cycles: Fatness as a Determinant of Minimum Weight for Height Necessary for Their Maintenance or Onset},
  volume    = {185},
  number    = {4155},
  pages     = {949--951},
  year      = {1974},
  doi       = {10.1126/science.185.4155.949},
  abstract  = {Weight loss causes loss of menstrual function (amenorrhea) and weight gain restores menstrual cycles. A minimal weight for height necessary for the onset of or the restoration of menstrual cycles in cases of primary or secondary amenorrhea due to undernutrition is indicated by an index of fatness of normal girls at menarche and at age 18 years, respectively. Amenorrheic patients of ages 16 years and over resume menstrual cycles after weight gain at a heavier weight for a particular height than is found at menarche. Girls become relatively and absolutely fatter from menarche to age 18 years. The data suggest that a minimum level of stored, easily mobilized energy is necessary for ovulation and menstrual cycles in the human female.},
  issn      = {0036-8075},
  URL       = {https://science.sciencemag.org/content/185/4155/949},
  eprint    = {https://science.sciencemag.org/content/185/4155/949.full.pdf},
  journal   = {Science}
}

@article{fristoe2015metabolic,
  author    = {Fristoe, Trevor S. and Burger, Joseph R. and Balk, Meghan A. and Khaliq, Imran and Hof, Christian and Brown, James H.},
  title     = {Metabolic heat production and thermal conductance are mass-independent adaptations to thermal environment in birds and mammals},
  volume    = {112},
  number    = {52},
  pages     = {15934--15939},
  year      = {2015},
  doi       = {10.1073/pnas.1521662112},
  publisher = {National Academy of Sciences},
  abstract  = {How different kinds of organisms adapt to environmental temperature is central to understanding how they respond to past, present, and future climate change. We applied the Scholander{\textendash}Irving model of thermoregulation to data on hundreds of species of birds and mammals to assess the contributions of three avenues of adaptation to environmental temperature: body size, basal metabolic rate (BMR), and thermal conductance. Adaptation via body size is limited; the entire ranges of body sizes of birds and mammals occur in nearly all climatic regimes. Using physiological and environmental data for 211 bird and 178 mammal species, we demonstrate that birds and mammals have adapted to geographic variation in environmental temperature regimes by concerted changes in both BMR and thermal conductance.The extent to which different kinds of organisms have adapted to environmental temperature regimes is central to understanding how they respond to climate change. The Scholander{\textendash}Irving (S-I) model of heat transfer lays the foundation for explaining how endothermic birds and mammals maintain their high, relatively constant body temperatures in the face of wide variation in environmental temperature. The S-I model shows how body temperature is regulated by balancing the rates of heat production and heat loss. Both rates scale with body size, suggesting that larger animals should be better adapted to cold environments than smaller animals, and vice versa. However, the global distributions of \~{}9,000 species of terrestrial birds and mammals show that the entire range of body sizes occurs in nearly all climatic regimes. Using physiological and environmental temperature data for 211 bird and 178 mammal species, we test for mass-independent adaptive changes in two key parameters of the S-I model: basal metabolic rate (BMR) and thermal conductance. We derive an axis of thermal adaptation that is independent of body size, extends the S-I model, and highlights interactions among physiological and morphological traits that allow endotherms to persist in a wide range of temperatures. Our macrophysiological and macroecological analyses support our predictions that shifts in BMR and thermal conductance confer important adaptations to environmental temperature in both birds and mammals.},
  issn      = {0027-8424},
  URL       = {http://www.pnas.org/content/112/52/15934},
  eprint    = {http://www.pnas.org/content/112/52/15934.full.pdf},
  journal   = {Proceedings of the National Academy of Sciences}
}

@article{garrott2003climateinduced,
  author   = {Garrott, Robert A and Eberhardt, L Lee and White, Patrick J and Rotella, Jay},
  title    = {Climate-induced variation in vital rates of an unharvested large-herbivore population},
  journal  = {Canadian Journal of Zoology},
  volume   = {81},
  number   = {1},
  pages    = {33--45},
  year     = {2003},
  doi      = {10.1139/z02-218},
  URL      = { https://doi.org/10.1139/z02-218 },
  eprint   = { https://doi.org/10.1139/z02-218 },
  abstract = {Variation in vital rates of an unharvested elk (Cervus elaphus) population was studied using telemetry for 7 consecutive years, 1991–1998. We found pronounced senescence in survival rates, but no evidence for reproductive senescence. Prime-age females (<10 years old) experienced very high annual survival rates (mean = 0.97, SE = 0.02), with lower survival rates for senescent animals (10 years old; mean = 0.79, SE = 0.06). There was evidence that the severity of snowpack conditions had little effect on survival of prime-age animals except during the most extreme winter, while survival of senescent animals was progressively depressed as the severity of snowpack conditions increased. Reproductive rates remained essentially constant, near their biological maxima (mean = 0.91, SE = 0.02). Annual re cruitment was highly variable. Snowpack had a pronounced effect on recruitment (r2 = 0.91), the most severe snowpack conditions resulting in the virtual elimination of a juvenile cohort. Population estimates and recruitment rates obtained during this investigation and historic data collected from 1965 to 1980 support the premise that the population has been maintained in a dynamic equilibrium for at least three decades despite the stochastic effects of climate variation on vital rates. We conclude that the population is resource-limited, with variation about the equilibrium caused primarily by variable recruitment driven by stochastic annual snowpack.}
}

@article{givens1989digestibility,
  title   = {The digestibility and metabolisable energy content of grass silage and their prediction from laboratory measurements},
  volume  = {24},
  url     = {http://linkinghub.elsevier.com/retrieve/pii/0377840189900187},
  pages   = {27--43},
  number  = {1},
  journal = {Animal Feed Science and Technology},
  author  = {Givens, D.I. and Everington, Jeannie M. and Adamson, A.H.},
  year    = {1989}
}

@article{glazier2005beyond,
  title     = {Beyond the ‘3/4-power law’: variation in the intra- and interspecific scaling of metabolic rate in animals},
  volume    = {80},
  DOI       = {10.1017/S1464793105006834},
  number    = {4},
  journal   = {Biological Reviews},
  author    = {Glazier, Douglas S.},
  year      = {2005},
  pages     = {611--662}
}

@article{golley1961energy,
  author  = {Golley, Frank B.},
  title   = {Energy Values of Ecological Materials},
  journal = {Ecology},
  volume  = {42},
  number  = {3},
  pages   = {581--584},
  doi     = {10.2307/1932247},
  url     = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.2307/1932247},
  eprint  = {https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.2307/1932247},
  year    = {1961}
}

@collection{hall1990ecosystem,
  title     = {Ecosystem Modeling in Theory and Practice: An Introduction with Case Histories},
  author    = {Hall, Charles A. S. and Day, John W.},
  year      = {1990},
  edition   = {2},
  address   = {Niwot, Colorado},
  publisher = {University Press of Colorado}
}
https://hds.hebis.de/ubffm/Record/HEB023556463

@inproceedings{hanks2004characterization,
  crossref = {fowler2004dynamics},
  author   = {Hanks, John},
  title    = {Characterization of Population Condition},
  chapter  = {3},
  pages    = {47--74}
}

@book{guthrie1990frozen,
  title     = {Frozen fauna of the mammoth steppe: the story of Blue Babe},
  pagetotal = {xiv+323},
  publisher = {University of Chicago Press},
  isbn      = {9780226159713},
  author    = {Guthrie, R. Dale},
  year      = {1990}
}

@article{hardin1960competitive,
  author    = {Hardin, Garrett},
  title     = {The Competitive Exclusion Principle},
  volume    = {131},
  number    = {3409},
  pages     = {1292--1297},
  year      = {1960},
  doi       = {10.1126/science.131.3409.1292},
  publisher = {American Association for the Advancement of Science},
  issn      = {0036-8075},
  URL       = {http://science.sciencemag.org/content/131/3409/1292},
  eprint    = {http://science.sciencemag.org/content/131/3409/1292.full.pdf},
  journal   = {Science}
}

@article{hobbs2003challenges,
  title    = {Challenges and opportunities in integrating ecological knowledge across scales},
  journal  = {Forest Ecology and Management},
  volume   = {181},
  number   = {1},
  pages    = {223--238},
  year     = {2003},
  note     = {Forest Dynamics and Ungulate Herbivory : From Leaf to Landscape},
  issn     = {0378-1127},
  doi      = {https://doi.org/10.1016/S0378-1127(03)00135-X},
  url      = {http://www.sciencedirect.com/science/article/pii/S037811270300135X},
  author   = {N. Thompson Hobbs},
  keywords = {Scale, Resource management, Ungulate, Adaptive management, Heterogeneity, Model selection},
  abstract = {Choices of the spatial and temporal dimensions of ecological investigations define their scale. In this paper, I identify some of the ways that issues of scale challenge ecologists in developing an understanding of natural and human-dominated systems, with particular reference to understanding interactions between ungulates and landscapes. I also point out opportunities to rise to those challenges. Ecologists often study areas of land that represent only a tiny fraction of the area that is managed for natural resources or other human uses. This mismatch between scales of investigation and scales of management is problematic because observations of many phenomena depend on the scale at which those observations are made. Conducting traditional experiments at ever-larger scales would appear to offer a logical solution to this problem, but the “tyranny of power” means that such investigations are frequently infeasible. Moreover, because human perception is based on limited scales of experience, it is often difficult to apply understanding of ecological processes occurring over long time periods and large areas. The ability of ecologists to integrate knowledge across scales in a way that is useful to management has improved dramatically as a result of technological advances, innovations in statistical analysis and study design, and a shift in the philosophy of science favoring model selection over traditional hypothesis testing. Multi-scale understanding is fostered by adaptive management, which uses fine-scale, mechanistic understanding to screen hypotheses to be tested at large-scales. Issues of scale reveal that applying ecological understanding to complex environmental problems requires two kinds of science—developing an understanding of properties and processes and assembling that understanding reliably across scales of time and space.}
}

@incollection{hobbs2006large,
  crossref = {danell2006large},
  title    = {Large herbivores as sources of disturbance in ecosystems},
  pages    = {261--288},
  author   = {Hobbs, N. Thompson},
}

@article{hogg2017capital,
  author    = {Hogg, John T. and Dunn, Stacey J. and Poissant, Jocelyn and Pelletier, Fanie and Byers, John A.},
  year      = {2017},
  title     = {Capital vs. income‐dependent optimal birth date in two North American ungulates},
  journal   = {Ecosphere},
  issn      = {2150-8925},
  doi       = {10.1002/ecs2.1766},
  volume    = {8},
  month     = {4},
  number    = {4},
  url       = {https://doi.org/10.1002/ecs2.1766},
  abstract  = {Phenotypic plasticity in reproductive traits is of theoretical and applied interest as one avenue by which organisms might maintain an optimal annual reproductive routine in the face of cyclic and/or directional change in environmental conditions. We used long-term, individual-based data from parapatric populations of bighorn sheep (Ovis canadensis canadensis) and pronghorn (Antilocapra americana) to evaluate plasticity in breeding date, gestation duration, birth date, birth mass, and fetal growth rate in response to inter-annual (cyclic) variation in indices of maternal energy income and expense. Traits in both species responded plastically to variation in maternal energy balance. However, despite nearly identical climate and similar vegetative habitat, plasticity was expressed in fundamentally different ways in the study species. Variation in bighorn birth date was primarily due to plasticity in breeding date, whereas variation in pronghorn birth date was primarily due to variation in gestation duration. Across traits, bighorn plastic responses were more consistent with explanations that invoked periodic energy surplus as the basis for plasticity, whereas pronghorn plastic responses were more consistent with explanations that invoked periodic energy deficiency. Later birth date was associated with increased fetal growth rate in bighorn but decreased fetal growth rate in pronghorn. Finally, we detected strong directional selection for early birth among bighorn mothers but found no evidence of selection on pronghorn birth date. Collectively, our results indicate markedly different maternal tactics for timing birth. Bighorn mothers appeared to use stored energy to subsidize the cost of birth prior to the local environmental optimum in an energy-mediated competition with other females to minimize birth order rank. Pronghorn mothers, committed to high levels of energy allocation to offspring and subject therefore to frequent energy deficiency, timed birth conservatively to more closely match peak reproductive expenditure with peak energy income at the local environmental optimum.}
}

@article{holling1959components,
  title    = {The Components of Predation as Revealed by a Study of Small-Mammal Predation of the European Pine Sawfly},
  volume   = {91},
  issn     = {1918-3240},
  url      = {http://journals.cambridge.org/article_S0008347X00072564},
  doi      = {10.4039/Ent91293-5},
  abstract = {The fluctuation of an animal's numbers between restricted limits is determined by a balance between that animal's capacity to increase and the environmenta1 cheks to this increase. Many authors have indulged in the calculating the propressive increase of a population when no checks nrerc operating. Thus Huxley calculated that the progeny of a single Aphis in the course of 10 generations, supposing all survived,would “contain more ponderable substance than five hundred millions of stout men; that is, more than the whole population of China”, (in Thompson, 1929). Checks, however, do occur and it has been the subject of much controversy to determine how these checks operate. Certain general principles—the density-dependence concept of Smith ( 1955) , the competition theory of Nicholson (1933)—have been proposed both verbally and mathematically, but because they have been based in part upon untested and restrictive assumptions they have been severelv criticized (e.g. Andrewartha and Birch 1954). These problems could be considerably clarified if we knew the mode of operation of each process that affects numbers, if we knew its basic and subsidiary components. predation, one such process, forms the subject of the present paper.},
  pages    = {293--320},
  number   = {5},
  journal  = {The Canadian Entomologist},
  author   = {Holling, C. S.},
  year     = {1959},
  month    = {05}
}

@article{holling1959some,
  title   = {Some Characteristics of Simple Types of Predation and Parasitism},
  volume  = {91},
  DOI     = {10.4039/Ent91385-7},
  number  = {7},
  journal = {The Canadian Entomologist},
  author  = {Holling, C. S.},
  year    = {1959},
  pages   = {385--398}
}

@book{hudson1985bioenergetics,
  title     = {Bioenergetics of wild herbivores},
  isbn      = {0-8493-5911-2},
  publisher = {{CRC} press},
  author    = {Hudson, Robert J. and White, Robert G.},
  year      = {1985},
  isbn      = {9780849359118}
}

@article{hyvonen1996approach,
  title    = {Approach to fat analysis of foods},
  journal  = {Food Chemistry},
  volume   = {57},
  number   = {1},
  pages    = {23--26},
  year     = {1996},
  note     = {The Second International Food Data Base Conference: Food Composition Research - The Broader Context},
  issn     = {0308-8146},
  doi      = {https://doi.org/10.1016/0308-8146(96)00058-1},
  url      = {http://www.sciencedirect.com/science/article/pii/0308814696000581},
  author   = {Lea Hyvönen},
  abstract = {Behind the nutritional labelling of food fat hides a problem of definition of fat, as well as an analytical problem. Although triacylglycerols are the prevailing structure of the food lipids in most cases, there are exceptions, too. Analytes called ether extract, crude fat, total fat and total lipids have been interpreted to food fat in nutritional labelling and food databases. However, the techniques traditionally used for fat determination in foods may vary considerably in their ability to recover the various lipid components. Diversity in the lipid composition of various foods and the effects of processing and storage on the diversity and availability of the fat make the correct nutritional labelling of fat problematic. The traditional methods, where the total fat content is determined by extracting the fat with an appropriate fat solvent or a solvent mixture, give good technical measures. The use of this extracted fat-soluble material as the nutritional concept of fat may be misleading. We have suggested (Hyvönen et al., 1993, J. Food Comp. Anal., 6, 24–40) the use of the concept of net fat in nutritional food labelling. This definition of fat includes all the unchanged fatty acids from the various food lipids converted to triacylglycerols. In energy calculations 1 g of net fat corresponds to 9 kcal or 38 kJ. This concept reduces the energy values of foods because it eliminates the lipid components, which are not real fats, from the calculation.}
}

@article{illius1991prediction,
  title     = {Prediction of intake and digestion in ruminants by a model of rumen kinetics integrating animal size and plant characteristics},
  volume    = {116},
  DOI       = {10.1017/S0021859600076255},
  number    = {1},
  journal   = {The Journal of Agricultural Science},
  author    = {Illius, A. W. and Gordon, I. J.},
  year      = {1991},
  pages     = {145--157}
}

@article{illius1992modelling,
  title    = {Modelling the nutritional ecology of ungulate herbivores: evolution of body size and competitive interactions},
  volume   = {89},
  issn     = {0029-8549, 1432-1939},
  url      = {http://link.springer.com/article/10.1007/BF00317422},
  abstract = {Summary A simulation model is used to quantify relationships between diet quality, digestive processes and body weight in ungulate herbivores. Retention time of food in the digestive tract is shown by regression to scale with W0.27, and to be longer in ruminants than in hindgut fermenters. Allometric relationships between whole gut mean retention time ({MRT}, h) and weight (W) were: {MRT} = 9.4 W0.255 (r 2 = 0.80) for hindgut fermenters and {MRT} = 15.3 W0.251 (r 2 = 0.76) in ruminants. Longer retention of ingesta by large-bodied ruminants and hindgut fermenters increases digestive efficiency relative to small animals and permits them to survive on lower-quality foods. Compared with ruminants, hindgut fermenters' faster throughput is an advantage which outweighs their lower digestive efficiency, particularly on poor quality foods, provided that food resources are not limiting. This suggests that the predominance of ruminants in the middle range of body weights results from their more efficient use of scarce resources under conditions of resource depletion. Considering only physical limitations on intake, the model shows that the allometric coefficient which scales energy intake to body mass is 0.88 in ruminants and 0.82 in hindgut fermenters. The advantages of large body size are countered by disadvantages where food quantity is limited, and we suggest that the upper limit to ungulate body size is determined by the ability to extract nutrients from feeding niches during the nadir of the seasonal cycle of resource quality and abundance.},
  pages    = {428--434},
  number   = {3},
  journal  = {Oecologia},
  author   = {Illius, A. W. and Gordon, I. J.},
  year     = {1992}
}

@article{illius1994costs,
  title   = {Costs of vigilance in foraging ungulates},
  journal = {Animal Behaviour},
  volume  = {47},
  number  = {2},
  pages   = {481 - 484},
  year    = {1994},
  issn    = {0003-3472},
  doi     = {https://doi.org/10.1006/anbe.1994.1067},
  author  = {A.W. Illius and C. Fitzgibbon}
}

@book{illius1999scaling,
  title     = {Scaling up from functional response to numerical response in vertebrate herbivores},
  publisher = {Blackwell Science},
  author    = {Illius, A. W. and Gordon, I. J.},
  year      = {1999}
}

@article{illius2000resource,
  title    = {Resource Heterogeneity and Ungulate Population Dynamics},
  volume   = {89},
  url      = {http://dx.doi.org/10.1034/j.1600-0706.2000.890209.x},
  abstract = {It has been suggested that climatic variation has the effect on the dynamics of arid and semi-arid grazing systems of reducing animal numbers below the level at which they have much impact on vegetation or soils, and that spatial heterogeneity in resource availability serves to buffer herbivores against climatic variation. Modelling was used to test these hypotheses and to examine the interacting effects of temporal and spatial variability in plant production on animal population dynamics and defoliation intensity. The model distinguishes areas of the range that are accessible during wet and dry seasons, and examines the effect of seasonal restrictions in foraging area. It was established that the animal population is in long-term equilibrium with dry-season resources, on which it depends for survival; that dry season resource areas and outlying areas thus operate in a source-sink manner; and that the ratio of these areas determines the strength of consumer-resource coupling outside the dry-season range. A high ratio of dry season to wet season resources may support a sufficiently large animal population to impose non-trivial defoliation impacts on the outlying range. Increasing degrees of variability in primary production on areas used by animals for surviving the dry season increased the annual variation in animal abundance and reduced the mean. By comparison with a stable environment, for which the model predicts virtually stable animal numbers and constant, low defoliation intensity, variation in annual rainfall causes wide fluctuations in animal numbers and defoliation intensity. Under climatic variation, animal numbers can build up enough to impose much higher defoliation intensities than under a constant regime. Periodic intense defoliation is a consequence of climatic variability which is likely to make these environments more, not less, prone to ecological change.},
  pages    = {283--294},
  number   = {2},
  journal  = {Oikos},
  author   = {Illius, A. W. and O'Connor, T. G.},
  year     = {2000}
}

@inproceedings{johnson1982intake,
  title     = {Intake, apparent utilization and rate of digestion in mares and cows.},
  isbn      = {0569-7832},
  booktitle = {Proceedings of the Annual Meeting. American Society for Animal Science Western Section},
  author    = {Johnson, D. E. and Borman, M. M. and Rittenhouse, L. R.},
  year      = {1982}
}

@article{kleiber1961fire,
  title    = {The fire of life},
  subtitle = {An introduction to animal energetics},
  author   = {Kleiber, Max},
  year     = {1961}
}

@article{klein1968reindeer,
  ISSN      = {0022541X, 19372817},
  URL       = {https://doi.org/10.2307/3798981},
  abstract  = {Reindeer (Rangifer tarandus), introduced to St. Matthew Island in 1944, increased from 29 animals at that time to 6,000 in the summer of 1963, and underwent a crash die-off the following winter to less than 50 animals. In 1957, the body weight of the reinder was found to exceed that of reindeer in domestic herds by 24-53 percent among females and 46-61 percent among males. The population also responded to the high quality and quantity of the forage on the island by increasing rapidly due to a high birth rate and low mortality. By 1963, the density of the reindeer on the island had reached 46.9 per square mile and ratios of fawns and yearlings to adult cows had dropped from 75 and 45 percent respectively, in 1957 to 60 and 26 percent in 1963. Average body weights had decreased from 1957 by 38 percent for adult females and 43 percent for adult males and were comparable to weights of reindeer in domestic herds. Lichens had been completely eliminated as a significant component of the winter diet. Sedges and grasses were expanding into sites previously occupied by lichens. In the late winter of 1963-64, in association with extreme snow accumulation, virtually the entire population of 6,000 reindeer died of starvation. With one known exception, all of the surviving reindeer (42 in 1966) were females. The pattern of reindeer population growth and die-off on St. Matthew Island has been observed on other island situations with introduced animals and is believed to be a product of the limited development of ecosystems and the associated deficiency of potential population-regulating factors on islands. Food supply, through its interaction with climatic factors, was the dominant population regulating mechanism for reindeer on St. Matthew Island.},
  author    = {David R. Klein},
  journal   = {The Journal of Wildlife Management},
  number    = {2},
  pages     = {350--367},
  title     = {The Introduction, Increase, and Crash of Reindeer on St. Matthew Island},
  volume    = {32},
  year      = {1968}
}

@inproceedings{ledger1968body,
  title     = {Body composition as a basis for a comparative study of some East African mammals},
  volume    = {21},
  pages     = {289--310},
  booktitle = {Symp. Zool. Soc. Lond},
  author    = {Ledger, H. P.},
  year      = {1968}
}

@article{lee2019robust,
  author   = {Lee, Michael D. and Criss, Amy H. and Devezer, Berna and Donkin, Christopher and Etz, Alexander and Leite, F{\'a}bio P. and Matzke, Dora and Rouder, Jeffrey N. and Trueblood, Jennifer S. and White, Corey N. and Vandekerckhove, Joachim},
  title    = {Robust Modeling in Cognitive Science},
  journal  = {Computational Brain {\&} Behavior},
  year     = {2019},
  month    = {12},
  day      = {01},
  volume   = {2},
  number   = {3},
  pages    = {141--153},
  abstract = {In an attempt to increase the reliability of empirical findings, psychological scientists have recently proposed a number of changes in the practice of experimental psychology. Most current reform efforts have focused on the analysis of data and the reporting of findings for empirical studies. However, a large contingent of psychologists build models that explain psychological processes and test psychological theories using formal psychological models. Some, but not all, recommendations borne out of the broader reform movement bear upon the practice of behavioral or cognitive modeling. In this article, we consider which aspects of the current reform movement are relevant to psychological modelers, and we propose a number of techniques and practices aimed at making psychological modeling more transparent, trusted, and robust.},
  issn     = {2522-087X},
  doi      = {10.1007/s42113-019-00029-y},
  url      = {https://doi.org/10.1007/s42113-019-00029-y}
}

@inbook{lopez2000prediction,
  author   = {López, S. and Dijkstra, J. and France, J.},
  crossref = {givens2000forage},
  title    = {Prediction of Energy Supply in Ruminants, with Emphasis on Forages},
  pages    = {63--94},
  chapter  = {4}
}

@article{nosek2018preregistration,
  author   = {Nosek, Brian A. and Ebersole, Charles R. and DeHaven, Alexander C. and Mellor, David T.},
  title    = {The preregistration revolution},
  volume   = {115},
  number   = {11},
  pages    = {2600--2606},
  year     = {2018},
  doi      = {10.1073/pnas.1708274114},
  abstract = {Progress in science relies in part on generating hypotheses with existing observations and testing hypotheses with new observations. This distinction between postdiction and prediction is appreciated conceptually but is not respected in practice. Mistaking generation of postdictions with testing of predictions reduces the credibility of research findings. However, ordinary biases in human reasoning, such as hindsight bias, make it hard to avoid this mistake. An effective solution is to define the research questions and analysis plan before observing the research outcomes{\textemdash}a process called preregistration. Preregistration distinguishes analyses and outcomes that result from predictions from those that result from postdictions. A variety of practical strategies are available to make the best possible use of preregistration in circumstances that fall short of the ideal application, such as when the data are preexisting. Services are now available for preregistration across all disciplines, facilitating a rapid increase in the practice. Widespread adoption of preregistration will increase distinctiveness between hypothesis generation and hypothesis testing and will improve the credibility of research findings.},
  issn     = {0027-8424},
  URL      = {https://www.pnas.org/content/115/11/2600},
  eprint   = {https://www.pnas.org/content/115/11/2600.full.pdf},
  journal  = {Proceedings of the National Academy of Sciences}
}

@incollection{maff1984energy,
  title     = {Energy allowances and feeding systems for ruminants},
  booktitle = {Reference Booklet 433},
  publisher = {{HMSO} London},
  author    = {{MAFF} and {DAFS} and {DANI}},
  year      = {1984}
}

@article{makarieva2009comment,
  author   = {Makarieva, Anastassia M. and Gorshkov, Victor G. and Li, Bai-Lian},
  title    = {Comment on “Energy Uptake and Allocation During Ontogeny”},
  volume   = {325},
  number   = {5945},
  pages    = {1206--1206},
  year     = {2009},
  doi      = {10.1126/science.1171303},
  abstract = {We demonstrate that the model of energy allocation during ontogeny of Hou et al. (Reports, 31 October 2008, p. 736) fails to account for the observed elevation of metabolic rate in growing organisms compared with similarly sized adults of different species. The basic model assumptions of the three-quarter power scaling for resting metabolism and constancy of the mass-specific maintenance metabolism need to be reassessed.},
  issn     = {0036-8075},
  URL      = {https://science.sciencemag.org/content/325/5945/1206.1},
  eprint   = {https://science.sciencemag.org/content/325/5945/1206.1.full.pdf},
  journal  = {Science}
}

@book{mcdonald2010animal,
  title     = {Animal Nutrition},
  year      = {2011},
  edition   = {7},
  author    = {McDonald, P. AND Edwards, R. A. AND Greenhalgh, J. F. D. AND Morgan, C. A. AND Sinclair, L. A. AND Wilkinson, R. G.},
  publisher = {Prentice Hall}
}

@book{minson1990forage,
  title     = {Forage in Ruminant Nutrition},
  author    = {Minson, Dennis J.},
  isbn      = {0124983103},
  series    = {Animal feeding and nutrition},
  address   = {San Diego, California},
  year      = {1990},
  publisher = {Academic Press}
}

@incollection{oreskes2003role,
  crossref = {canham2003models},
  author   = {Oreskes, Naomi},
  title    = {The Role of Quantitative Models in Science},
  chapter  = {2},
  pages    = {13--31}
}

@incollection{overton1990strategy,
  crossref = {hall1990ecosystem},
  pages    = {49--73},
  title    = {A Strategy of Model Construction},
  author   = {Overton, W. S.}
}

@article{owensmith2002metaphysiological,
  title    = {A metaphysiological modelling approach to stability in herbivore–vegetation systems},
  journal  = {Ecological Modelling},
  volume   = {149},
  number   = {1},
  pages    = {153 - 178},
  year     = {2002},
  issn     = {0304-3800},
  doi      = {http://dx.doi.org/10.1016/S0304-3800(01)00521-X},
  url      = {http://www.sciencedirect.com/science/article/pii/S030438000100521X},
  author   = {Norman Owen-Smith},
  keywords = {Consumer–resource dynamics},
  keywords = {Herbivore–vegetation systems},
  keywords = {Metaphysiological modelling},
  keywords = {Seasonality},
  abstract = {The metaphysiological modelling approach relates aggregated population dynamics to biomass gained from resources consumed, relative to physiological attrition and mortality losses. A GMM (Growth, Metabolism and Mortality) formulation was applied to the interactive dynamics of herbivore–vegetation systems, taking into account seasonality in resource production, heterogeneity in resource quality, adaptive responses by consumers to this variability, and nutritional influences on mortality losses. In transforming the intake or functional response to changing resource availability to a biomass gain response, allowance was made for constraints on daily digestive capacity, and for changing diet quality as resources became depleted over the seasonal cycle. Because of the steeply saturating form of the intake response, the output dynamics was inherently unstable in a constant environment with a single, uniform resource, for realistic parameter values. Stabilization resulted when resources were heterogeneous and herbivores adjusted their resource selection adaptively over the course of the year. This mechanism caused the gain response to diverge from the intake response, due to changing diet quality over the annual cycle. In seasonally varying environments, no equilibrium between resource production and consumption persists. Nevertheless, dynamic stability can emerge from the adaptive responses of consumers to spatial and temporal variability in resource availability and quality.}
}

@article{owensmith2004functional,
  author   = {Owen-Smith, Norman},
  title    = {Functional heterogeneity in resources within landscapes and herbivore population dynamics},
  journal  = {Landscape Ecology},
  year     = {2004},
  month    = {10},
  day      = {01},
  volume   = {19},
  number   = {7},
  pages    = {761--771},
  abstract = {Large mammalian herbivores are notorious for their propensity towards population irruptions and crashes, yet many herbivore populations remain relatively stable. I explore how resource heterogeneity within landscapes dampens population instability, using a metaphysiological modelling approach considering patch state distributions. Resource heterogeneity is functionally stabilizing through spreading consumption away from preferred resources before these become critically depleted. Lower-quality resources act as a buffer against starvation during critical periods of the seasonal cycle. Enriching resource quality is destabilizing, even if patch diversity is maintained, because food quantity then becomes the limitation. The potential consequences of landscape fragmentation are explored using the Serengeti ecosystem, characterised by broadscale resource gradients, as a hypothetical example. Further insights provided by the model are illustrated with specific examples concerning the effects of patch scales and waterpoint distribution. A metaphysiological modelling approach enables the basic consequences of landscape heterogeneity to be distinguished from further effects that may arise from specific patch scales and configurations, without the distracting detail of spatially explicit models.},
  issn     = {1572-9761},
  doi      = {10.1007/s10980-005-0247-2},
  url      = {https://doi.org/10.1007/s10980-005-0247-2}
}

@article{pachzelt2013coupling,
  author   = {Adrian Pachzelt and Anja Rammig and Steven Higgins and Thomas Hickler},
  title    = {Coupling a physiological grazer population model with a generalized model for vegetation dynamics},
  journal  = {Ecological Modelling},
  volume   = {263},
  pages    = {92--102},
  year     = {2013},
  issn     = {0304-3800},
  doi      = {http://dx.doi.org/10.1016/j.ecolmodel.2013.04.025},
  url      = {http://www.sciencedirect.com/science/article/pii/S0304380013002494},
  keywords = {Herbivore population dynamics},
  keywords = {African ungulates},
  keywords = {Savannahs},
  keywords = {Vegetation modelling},
  abstract = { Large grazers have played a fundamental role in grassland and savannah ecosystems since these vegetation types formed in the late Miocene, but the feedback loops between vegetation and large grazers are still not well understood. Modern dynamic global vegetation models (DGVMs) lack the explicit impact of herbivory, but are calibrated to benchmarks including herbivory. We coupled a generalized model for the population dynamics of large mammalian grazers, based on animal physiology, with a plant-physiological model for vegetation dynamics and ecosystem processes, applicable at local to global scales (LPJ-GUESS). To our knowledge, this is the first attempt to combine process-based grazer population and vegetation modelling in a single generalized modelling framework, applicable at regional to continental scales. The capability of the coupled model to reproduce real-world grazer densities was tested by comparing modelled biomass densities with empirical data from African game parks, where semi-natural grazer populations still exist. The model reproduced inter-park differences in long-term average grazer biomass densities and yielded similar dependencies between major environmental drivers (e.g. precipitation, annual net primary productivity (NPP), dry season length) and grazer population densities as found in other more empirical studies. Amongst the potential environmental drivers, modelled NPP and dry season length were most strongly correlated with empirical and modelled biomass densities. Major discrepancies between modelled and empirical densities occurred for individual parks, but this was expected because the model did not include all factors that influence grazer populations (e.g. nutrient dynamics and poaching). The generalized flexible framework of the coupled model makes it possible to apply the model to other regions, to include further processes (if data for parameterizing them is available) and to parameterize other types of grazers. It could become a useful tool for investigating interactions between grazers and vegetation in a process-based framework.}
}

@article{pachzelt2015potential,
  title   = {Potential impact of large ungulate grazers on African vegetation, carbon storage and fire regimes: Grazer impacts on African savannas},
  volume  = {24},
  url     = {http://doi.wiley.com/10.1111/geb.12313},
  pages   = {991--1002},
  number  = {9},
  journal = {Global Ecology and Biogeography},
  author  = {Pachzelt, Adrian and Forrest, Matthew and Rammig, Anja and Higgins, Steven I. and Hickler, Thomas},
  year    = {2015}
}

@article{parker1993seasonal,
  author   = {Parker, Katherine L. and Gillingham, Michael P. and Hanley, Thomas A. and Robbins, Charles T.},
  title    = {Seasonal patterns in body mass, body composition, and water transfer rates of free-ranging and captive black-tailed deer (Odocoileus hemionus sitkensis) in Alaska},
  journal  = {Canadian Journal of Zoology},
  volume   = {71},
  number   = {7},
  pages    = {1397--1404},
  year     = {1993},
  doi      = {10.1139/z93-193},
  URL      = { https://doi.org/10.1139/z93-193 },
  eprint   = { https://doi.org/10.1139/z93-193 },
  abstract = { Body mass, body composition, and water transfer rates were determined over a continuous 2-year period in nine free-ranging Sitka black-tailed deer (Odocoileus hemionus sitkensis). Body masses showed a cyclical pattern, declined 14 – 31% between October and March, and were best described by a five-parameter, biologically based regression model. The amount of mass lost by black-tailed deer over winter depended on the peak body mass attained during fall. During winter, animals used 70 – 82% of their body fat and 10 – 15% of their protein reserves. Body fat was preferentially mobilized at rates 2.3 – 11.6 times higher than protein. Because of the higher energy content of fat, fat accounted for 83 – 92% of the catabolized energy. Water transfer rates varied seasonally with average summer values approximately four times those of winter; lactating deer had significantly higher rates of water transfer than nonlactating animals. Seasonal changes in all of the above parameters for wild deer were greater than those for eight deer of the same age in captivity. }
}

@article{parker1996foraging,
  author   = {Parker, Katherine L. and Gillingham, Michael P. and Hanley, Thomas A. and Robbins, Charles T.},
  title    = {Foraging efficiency: energy expenditure versus energy gain in free-ranging black-tailed deer},
  journal  = {Canadian Journal of Zoology},
  volume   = {74},
  number   = {3},
  pages    = {442--450},
  year     = {1996},
  doi      = {10.1139/z96-051},
  URL      = { https://doi.org/10.1139/z96-051 },
  eprint   = { https://doi.org/10.1139/z96-051 },
  abstract = { Foraging efficiency (metabolizable energy intake/energy expenditure when foraging) was determined over a 2-year period in nine free-ranging Sitka black-tailed deer (Odocoileus hemionus sitkensis) in Alaska, and related to foraging-bout duration, distances travelled, and average speeds of travel. We calculated the energy-intake component from seasonal dry matter and energy content, dry matter digestibility, and a metabolizable energy coefficient for each plant species ingested. We estimated energy expenditures when foraging as the sum of energy costs of standing, horizontal and vertical locomotion, sinking depths in snow, and supplementary expenditures associated with temperatures outside thermoneutrality. Energy intake per minute averaged 4.0 times more in summer than winter; energy expenditure was 1.2 times greater in summer. Animals obtained higher amounts of metabolizable energy with higher amounts of energy invested. Energy intake during foraging bouts in summer was 2.5 times the energy invested; in contrast, energy intake during winter was only 0.7 times the energy expended. Changes in body mass of deer throughout the year increased asymptotically with foraging efficiency, driven primarily by the rate of metabolizable energy intake. Within a season, summer intake rates and winter rates of energy expediture had the greatest effects on the relation between foraging efficiency and mass status. Seasonal changes in foraging efficiency result in seasonal cycles in body mass and condition in black-tailed deer. Body reserves accumulated during summer, however, are essential for over-winter survival of north-temperate ungulates because energy demands cannot be met by foraging alone. }
}

@book{peters1983ecological,
  location  = {Cambridge},
  edition   = {1st publ.},
  title     = {The ecological implications of body size},
  isbn      = {978-0-521-24684-2},
  series    = {Cambridge studies in ecology},
  pagetotal = {xii+329},
  number    = {2},
  publisher = {Cambridge University Press},
  author    = {Peters, Robert Henry},
  year      = {1983},
  abstract  = {It is generally recognized that larger animals eat more, live longer, have larger offspring, and so on; but it is unusual to see these commonplace observations as a basis for scientific biology. A large number of empirically based relationships describe biological rates as simple functions of body size; and other such relations predict the intrinsic rate of population growth, animal speed, animal density, territory size, prey size, physiology, and morphology. Such equations almost always exist for mammals and birds, often for other vertebrates and invertebrates, sometimes for protozoa, algae, and bacteria, and occasionally even for plants. There are too many organisms to measure all aspects of the biology of every species of population, so scientists must depend on generalizations. Body size relations represent our most extensive and powerful assemblage of generalizations, but they have never been organized for use in ecology. This book represents the largest single compilation of interspecific size relations, and instructs the reader on the use of these relationships; their comparison, combination, and criticism. Both strengths and weaknesses of our current knowledge are discussed in order to indicate the many possible directions for further research. This important volume will therefore provide a point of departure toward a new applied ecology, giving quantitative solutions to real questions. It will interest advanced students of ecology and comparative physiology as well as professional biologists.}
}

@incollection{price1985growth,
  crossref = {hudson1985bioenergetics},
  chapter  = {9},
  pages    = {183--214},
  author   = {Price, Mick A. and White, R. G.},
  title    = {Growth and Development}
}

@book{prins1996ecology,
  title     = {Ecology and behaviour of the African buffalo: social inequality and decision making},
  author    = {Prins, Herbert},
  volume    = {1},
  year      = {1996},
  publisher = {Springer Science \& Business Media}
}

@article{reimers1982body,
  author   = {Reimers, Eigil and Ringberg, Tata and Sørumgård, Rolf},
  title    = {Body composition of Svalbard reindeer},
  journal  = {Canadian Journal of Zoology},
  volume   = {60},
  number   = {8},
  pages    = {1812--1821},
  year     = {1982},
  doi      = {10.1139/z82-235},
  URL      = { https://doi.org/10.1139/z82-235 },
  eprint   = { https://doi.org/10.1139/z82-235 },
  abstract = {Tissue and (or) chemical body composition was determined in 18 Svalbard reindeer, aged 1½ months prepartum 9¾ to years, and in mainland Norway reindeer, aged 1½ months prepartum to 1⅓ years. At the end of the growing season, the fat content in the ingesta-free body was very high (27–40%) in Svalbard reindeer. Two mainland yearling males had 4.5% body fat as compared with 27.8% in a Svalbard male yearling. At the end of winter the weight decrease of Svalbard reindeer was close to 50%. The loss of ash, protein, water, and fat from the body was estimated at 16.8, 30.9, 34.3, and 76.3%, respectively. Animals that had starved to death showed an additional weight loss of 8% and a nearly complete loss of fat. Liver content of Fe increased from 97 mg/kg in late summer to 3463 mg/kg in late winter and 5075 mg/kg in animals that had starved to death. There were significant linear relationships between the percent water and percent fat in the ingesta-free body and between the weight of the fat-free and ingesta-free body and the weight of its components, namely water, protein, and ash.}
}

@book{robbins1983wildlife,
  title     = {Wildlife feeding and nutrition},
  isbn      = {978-0-12-589380-0},
  pagetotal = {xvi+343},
  publisher = {Academic Press},
  author    = {Robbins, Charles T.},
  year      = {1983},
  abstract  = {Wildlife Feeding and Nutrition is the fifth in a series of books on animal feeding and nutrition. It fills a serious gap in the wildlife and animal nutrition literature by providing a discussion of the basic principles of nutrition and their application to the broader field of wildlife ecology. This book is based on lectures presented in an upper-level wildlife nutrition course taught at Washington State University. The book discusses the five major nutritional categories of constituents that animals must acquire from their external environments: energy, protein, water, minerals, and vitamins. Subsequent chapters cover topics such as the estimation of energy and protein requirements; dietary protein requirements for captive wildlife and free-ranging populations; wildlife reproductive characteristics; the digestion and metabolism of nutrients; and food intake regulation. The text will be invaluable to wildlife biologists, to those who are interested in captive animal nutrition and management, and to those who are interested in improving the feed supply and nutrition of free-ranging wildlife.}
}

@article{robinson2012influence,
  author   = {Robinson, Barry G. and Merrill, Evelyn H.},
  title    = {The influence of snow on the functional response of grazing ungulates},
  year     = {2012},
  journal  = {Oikos},
  volume   = {121},
  number   = {1},
  pages    = {28--34},
  doi      = {10.1111/j.1600-0706.2011.19408.x},
  url      = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1600-0706.2011.19408.x},
  eprint   = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1600-0706.2011.19408.x},
  abstract = {The forage intake rate of grazing ungulates is limited either by the rate at which they encounter food items, or the rate at which food items are handled. Whether an ungulate is encounter- or handling-limited influences spatial and temporal depletion of forage, daily time budgets, and ultimately animal condition. Previously, vegetation abundance has been used as a surrogate for an ungulate's encounter rate with food items and related to observed bite rate to determine whether intake rate is encounter- or handling-limited. In temperate climates snow accumulation during winter limits access to vegetation by forcing animals to wade and paw through snow to consume underlying vegetation, increasing the amount of time required to encounter a food item. As a result, an ungulate may be handling-limited when foraging in a high biomass system under snow-free conditions, but becomes encounter-limited when snow accumulates. We derived a model that provides a frame work for estimating the rate at which a grazing ungulate encounters vegetation by considering foraging velocity, vegetation biomass and the time required to paw away snow when present. We then used data from focal observations of 36 wild elk Cervus canadensis wintering on a montane grassland in the Canadian Rockies of Alberta, Canada, to apply our model and estimate encounter rate over a range of vegetation abundance and snow conditions. Using AICc in a model selection approach we found that an asymptotic regression model of observed bite rate as a function of estimated encounter rate provided a better fit than similar models using only vegetation abundance as the explanatory variable. An asymptotic model suggests elk were handling-limited in the absence of snow, but became encounter-limited when snow accumulated. Our results demonstrate the importance of considering the influence of factors other than vegetation abundance on the intake rate of grazing ungulates.}
}

@article{schneider2012sense,
  author   = {Schneider, Jill and Klingerman, Candice and Abdulhay, Amir},
  title    = {Sense and Nonsense in Metabolic Control of Reproduction},
  journal  = {Frontiers in Endocrinology},
  volume   = {3},
  pages    = {26},
  year     = {2012},
  url      = {https://www.frontiersin.org/article/10.3389/fendo.2012.00026},
  doi      = {10.3389/fendo.2012.00026},
  issn     = {1664-2392},
  abstract = {An exciting synergistic interaction occurs among researchers working at the interface of reproductive biology and energy homeostasis. Reproductive biologists benefit from the theories, experimental designs, and methodologies used by experts on energy homeostasis while they bring context and meaning to the study of energy homeostasis. There is a growing recognition that identification of candidate genes for obesity is little more than meaningless reductionism unless those genes and their expression are placed in a developmental, environmental, and evolutionary context. Reproductive biology provides this context because metabolic energy is the most important factor that controls reproductive success and gonadal hormones affect energy intake, storage, and expenditure. Reproductive hormone secretion changes during development, and reproductive success is key to evolutionary adaptation, the process that most likely molded the mechanisms that control energy balance. It is likely that by viewing energy intake, storage, and expenditure in the context of reproductive success, we will gain insight into human obesity, eating disorders, diabetes, and other pathologies related to fuel homeostasis. This review emphasizes the metabolic hypothesis: a sensory system monitors the availability of oxidizable metabolic fuels and orchestrates behavioral motivation to optimize reproductive success in environments where energy availability fluctuates or is unpredictable.}
}

@article{scholander1950adaptation,
  author   = {P. F. Scholander and Raymond Hock and Vladimir Walters and Laurence Irving},
  title    = {Adaptation to cold in arctic and tropical mammals and birds in relation to body temperature, insulation, and basal metabolic rate},
  journal  = {The Biological Bulletin},
  volume   = {99},
  number   = {2},
  pages    = {259--271},
  year     = {1950},
  doi      = {10.2307/1538742},
  URL      = { https://doi.org/10.2307/1538742 },
  eprint   = { https://doi.org/10.2307/1538742 } ,
  abstract = { Maintenance of constant body temperature in a homoiothermic animal depends upon a balance between heat production and heat dissipation, and there are consequently three possible main avenues for climatic adaptation, (1) by body-to-air gradient, (2) by heat dissipation, and (3) by metabolic rate. There is no evidence of adaptive low body temperature in arctic mammals and birds, or high body temperature in tropical mammals and birds. The body-to-air gradient can be adapted only by means of behavioral thermoregulation (nest building, avoidance of direct sunshine, etc.). With few exceptions our adult arctic and tropical mammals and birds have a basal metabolic rate that fits the standard mouse to elephant curve, i.e., the basal metabolic rate is determined by an exponential relation to size; evidently fundamental to most animals, warm-blooded or not. The basal metabolic rate is consequently not influenced by such factors as temperature gradient and insulation which largely determine the heat loss, and is hence inadaptive to climate. Equally inadaptive is the body temperature, and the phylogenetic adaptation to cold or hot climate therefore has taken place only through factors that regulate the heat dissipation, notably the fur and skin insulation.For any temperature gradient where the body temperature is maintained, the over-all insulation and the metabolic rate must be so adjusted that their product is proportional to the gradient. This is confirmed by our material inasmuch as the observed critical gradients can be approximately predicted from fur insulation and basal metabolic rate. Under the same climatic conditions there may be an inverse relation between metabolic rate and fur insulation. }
}

@article{scholander1950heat,
  author   = {P. F. Scholander and Raymond Hock and Vladimir Walters and Fred Johnson and Laurence Irving},
  title    = {Heat regulation in some arctic and tropical mammals and birds},
  journal  = {The Biological Bulletin},
  volume   = {99},
  number   = {2},
  pages    = {237--258},
  year     = {1950},
  doi      = {10.2307/1538741},
  URL      = { https://doi.org/10.2307/1538741 },
  eprint   = { https://doi.org/10.2307/1538741 } ,
  abstract = { A series of arctic and tropical mammals and birds at Point Barrow, Alaska (lat. 71° N.) and in Panama (lat. 9° N.) was subjected to various air temperatures in a respiration chamber where the heat production was determined by oxygen consumption or carbon dioxide production. The larger arctic mammals and birds showed no increase in metabolism at — 30° C. and from observations on sleeping animals it is probable that their zone of thermoneutrality extends to — 40° C. or — 50° C. The smaller arctic species show a high critical temperature and the tropical species even higher. Metabolic heat production increases rapidly with lowering of the temperature in a tropical mammal or bird, and slowly in an arctic animal. It can be shown theoretically that in a thermoregulated system with a fixed basal energy level and variable insulation the critical gradient is proportional to the maximal insulation and the basal energy level.In a large series of experiments including our tropical and arctic animals, and all animals affording enough data in the literature, it is shown that the heat loss below the critical temperature is essentially proportional to the body-to-air gradient. This means that the overall insulation evidently reaches a maximum at the critical temperature and from then on the heat loss follows essentially Newton's law of cooling. It follows from this that an arctic mammal with a critical gradient of 70° C., by doubling its metabolism, theoretically would double the gradient. Only 40 per cent increase of its metabolism (or insulation) would suffice to take it down to — 70° C. which is near the lowest recorded temperature on earth.The very broad zone of thermoneutrality in the larger arctic species, from + 30° C. to — 40° C., shows their ability to balance an 11-fold increase in gradient and hence the animal can change its heat dissipation by a factor of 11 even when lying down. It is believed that vasomotor control of the poorly insulated legs must play an important role in the general thermoregulation of these animals.In the tropical mammals and birds the critical gradient is low, often only 10° C., which makes them sensitive to even small temperature changes. A 10° lowering of the air temperature from the critical temperature doubles the gradient for the tropical mammal; a 9° increase decreases the gradient 10 times, and in order to maintain the body temperature tropical animals must be able to adjust insulation and metabolism in the same proportion as the gradient. They are thus extremely sensitive to temperature changes.The whole range of heat regulation from tropical to arctic mammals and birds is represented on two charts, Figures 10 and 11. }
}

@article{shannon2013diet,
  title    = {Diet selection and seasonal dietary switch of a large sexually dimorphic herbivore},
  journal  = {Acta Oecologica},
  volume   = {46},
  pages    = {48--55},
  year     = {2013},
  issn     = {1146--609X},
  doi      = {https://doi.org/10.1016/j.actao.2012.10.013},
  url      = {http://www.sciencedirect.com/science/article/pii/S1146609X12001452},
  author   = {Graeme Shannon and Robin L. Mackey and Rob Slotow},
  keywords = {Foraging, Behavioural ecology, Browse, Graze, Elephant, },
  abstract = {Although diet selection and the physiological adaptations of grazers and browsers have been widely studied, much less is known about mixed-feeders that target both grass and woody species. The ability to switch diet allows the individual to respond to spatial and temporal changes in forage abundance and quality, providing a key mechanism for large herbivores to exploit heterogeneous environments. We compare diet selection and timing of the seasonal dietary switch for a large-bodied, sexually dimorphic mixed-feeder, the African elephant. The study was carried out on a small population of elephants (n  =  48) in the Pongola Game Reserve (PGR), South Africa. Sex-specific dietary composition evaluated from feeding behaviour correlated with composition in dung samples from individuals of known sex. Grass was strongly preferred during the wet season and browse in the winter dry season. However, adult male elephants switched from browse to grass earlier, and consumed a greater overall proportion of grass in their diet, compared with adult females and their associated family groups. Male elephants also spent more time in grassland habitats, and expanded their ranges to a greater extent than females following the end of the dry season. Our results suggest that smaller adult body size, high nutritional demands of offspring, and the constraints of sociality have contributed to female elephants in PGR resolving their diet selection strategies to target higher quality foraging opportunities, whilst males appear to be adopting a rate maximizing approach. The behavioural differences between the sexes are pronounced, which has implications for elephant management approaches that are typically focussed at the population level.}
}

@article{shipley1999predicting,
  title        = {Predicting Bite Size Selection of Mammalian Herbivores: A Test of a General Model of Diet Optimization},
  volume       = {84},
  issn         = {0030-1299},
  url          = {https://doi.org/10.2307/3546866},
  doi          = {10.2307/3546866},
  shorttitle   = {Predicting Bite Size Selection of Mammalian Herbivores},
  abstract     = {The architecture of woody food plants forces mammalian herbivores to make compromises in their food choices. Rapid rates of dry matter intake can be achieved by choosing large bites. For woody plants, however, such bites are low in nutritive quality relative to small bites taken from leaves or twigs near the growing point of the plant. This trade-off between food quality and food intake rate is central to diet optimization in browsing herbivores. We developed a model that predicts a quantitative solution to 'optimal bite size' (i.e., the bite that results in the greatest daily net energy intake) based on constraints in harvesting and digesting foods. This model responds to the chemistry and morphology of plants, and the size and digestive strategy (ruminant versus hindgut fermenter) of the herbivore. We tested the model by conducting a set of experiments in which we offered six species of dormant deciduous trees common to the boreal forests of Sweden to captive roe deer (Capreolus capreolus), red deer (Cervus elaphus), and moose (Alces alces). We also tested alternative hypotheses that animals crop bites merely in response to the morphological structure of twigs, or the distribution of twig sizes on trees. Twig diameters cropped by these animals were positively correlated with the diameter at current annual growth. However, structural measures of the trees alone were not sufficient to predict differences in choices of twig diameters among animal species. In contrast, the optimal bite size model accounted for the different bite sizes selected by animals of different sizes and explained 86\% of the variation in twig diameter cropped for all plant and animal species. Hence, we concluded that our model is useful for predicting, a priori, the twig diameters selected by herbivores on dormant deciduous trees. We suggest possible ways to enhance the model and how it can be used to assess forage availability, potential diet quality, and the vulnerability of trees to herbivory.},
  pages        = {55--68},
  number       = {1},
  journal      = {Oikos},
  author       = {Shipley, Lisa A. and Illius, Andrew W. and Danell, Kjell and Hobbs, N. T. and Spalinger, Donald E.},
  urldate      = {2015-10-19},
  year         = {1999}
}

@article{smallegange2002food,
  title    = {Food supply and demand, a simulation model of the functional response of grazing ruminants},
  journal  = {Ecological Modelling},
  volume   = {149},
  number   = {1},
  pages    = {179--192},
  year     = {2002},
  issn     = {0304-3800},
  doi      = {https://doi.org/10.1016/S0304-3800(01)00522-1},
  url      = {http://www.sciencedirect.com/science/article/pii/S0304380001005221},
  author   = {Isabel M. Smallegange and Arend M.H. Brunsting},
  keywords = {Resource ecology, Simulation model, Functional response, Herbivory, Voluntary intake, Foraging, African buffalo},
  abstract = {A dynamic model of the functional response is a first prerequisite to be able to bridge the gap between local feeding ecology and grazing rules that pertain to larger scales. A mechanistic model is presented that simulates the functional response, growth and grazing time of ruminants. It is based on results of studies on voluntary food intake and animal production of ruminants. Physiological requirements and food quality are key factors that determine the intake. The model is also based on the results of studies on the functional response of grazers. Quantitative aspects of vegetations i.e. bulk density and height, and the animals’ mouth dimensions are the main factors that determine how much a grazer can swallow. The structure of the model applies to ruminants under tropical conditions. The model parameters are set and validated for the African buffalo, Syncerus caffer. Three variants of the model are elaborated: a non-reproducing female, a reproducing female and a male ruminant. The similarity between the results of the simulation runs and field data are considered to be satisfactory. The results suggest that the quality of the vegetation i.e. the crude protein content, together with the animal's energy requirements, govern the daily intake of food. However, the quantitative characteristics of the vegetation, especially height, can be critical. The model aims to be a tool in the interpretation of empirical field data and in the development of grazing theory. Transparency, concision and a robust empirical basis were therefore striven after in the construction of the model.}
}

@article{soppela1986thermoregulation,
  title    = {Thermoregulation in reindeer},
  journal  = {Rangifer},
  year     = {1986},
  volume   = {6},
  number   = {2},
  pages    = {273--278},
  issn     = {0333-256X},
  url      = {https://www.ingentaconnect.com/content/doaj/0333256x/1986/00000006/00000002/art00039},
  doi      = {doi:10.7557/2.6.2.659},
  author   = {P{\"a}ivi Soppela and Mauri Nieminen and Jouni Timisj{\"a}rvi},
  abstract = {Thermoregulation was studied in Finnish reindeer (Rangifer tarandus L) on captive and herded individuals during 1977-85. Newborn calves maintained a high rectal temperature (Tre) (+39 to +41&deg;C) even at &mdash;23&deg;C by increasing heat production 5- to 6-fold through non-shivering thermogenesis, stimulated by cold-induced noradrenaline (NA). Plasma NA and thyroxine (T4) were high (18 ng/ml and 459 nmol/1) in neonatal reindeer. Sensitivity to exogenous NA was lost during the first 3-4 weeks of life. At +20&deg;C and above, calves increased Tre (ca 1&deg;C), oxygen consumption and heart rate, thereby showing poor heat tolerance. Thermal conductance was low in a cold environment, but rose sharply as ambient temperature (Ta) increased above + 10&deg;C. The Tre of adults (+ 38 to +39&deg;C) was independent of Ta (&mdash;28 to +15&deg;C). Coarse (hollow) hair density and length in adults averaged 2000/cm2 and 12 mm on the legs, 1000/cm3 and 30 mm on the abdomen and 1700/cm2 and 30 mm on the back (calves 3200/cm2, 10 mm), respectively. The dependence of skin temperature on the Ta was linear in excised fur samples, but complex in living animals being strongest in the legs. Serum adrenaline correlated with the weight, age and total lipids. Serum NA and dopamine-fi-hydroxylase were highest in spring and decreased by autumn. Serum T4 was highest in summer and lowest in spring.},
}

@article{spalinger1992mechanisms,
  author   = {Spalinger, Donald E. and Hobbs, N. Thompson},
  title    = {Mechanisms of Foraging in Mammalian Herbivores: New Models of Functional Response},
  journal  = {The American Naturalist},
  volume   = {140},
  number   = {2},
  pages    = {325--348},
  year     = {1992},
  doi      = {10.1086/285415},
  note     = {PMID: 19426061},
  URL      = { https://doi.org/10.1086/285415 },
  eprint   = { https://doi.org/10.1086/285415 } ,
  abstract = { The outcome of many high-order processes in ecology depends on the way in which the abundance and distribution of plants affect the eating rate of mammalian herbivores. However, simple, mechanistic models describing the operation of the functional response of these animals have failed to emerge. We offer new models describing the effects of spatial and morphological characteristics of plants on the intake rate of plant tissue by mammalian herbivores feeding within plant patches. We structure our models to respond to three patterns of plant availability: (1) spatially dispersed, apparent plants; (2) spatially dispersed, nonapparent plants; and (3) spatially concentrated plants. We depart from the traditional representations of predator functional response in assuming that searching for food and processing it can overlap in time. Our models illustrate that several distinct mechanisms can account for Type II functional responses frequently seen in herbivores. We show how differences among these mechanisms can explain anomalies in the empirical literature on regulation of intake rate of mammalian herbivores including divergence in functional responses between grazers and browsers, linear functional response curves, and curves showing zero slope throughout the domain of food availability. }
}

@article{stewart2005densitydependent,
  author   = {Stewart, Kelley M. and Bowyer, R. Terry. and Dick, Brian L. and Johnson, Bruce K. and Kie, John G.},
  title    = {Density-dependent effects on physical condition and reproduction in North American elk: an experimental test},
  journal  = {Oecologia},
  year     = {2005},
  month    = {03},
  day      = {01},
  volume   = {143},
  number   = {1},
  pages    = {85--93},
  abstract = {Density dependence plays a key role in life-history characteristics and population ecology of large, herbivorous mammals. We designed a manipulative experiment to test hypotheses relating effects of density-dependent mechanisms on physical condition and fecundity of North American elk (Cervus elaphus) by creating populations at low and high density. We hypothesized that if density-dependent effects were manifested principally through intraspecific competition, body condition and fecundity of females would be lower in an area of high population density than in a low-density area. Thus, we collected data on physical condition and rates of pregnancy in each experimental population. Our manipulative experiment indicated that density-dependent feedbacks affected physical condition and reproduction of adult female elk. Age-specific pregnancy rates were lower in the high-density area, although there were no differences in pregnancy of yearlings or in age at peak reproduction between areas. Age-specific rates of pregnancy began to diverge at 2 years of age between the two populations and peaked at 6 years old. Pregnancy rates were most affected by body condition and mass, although successful reproduction the previous year also reduced pregnancy rates during the current year. Our results indicated that while holding effects of winter constant, density-dependent mechanisms had a much greater effect on physical condition and fecundity than density-independent factors (e.g., precipitation and temperature). Moreover, our results demonstrated effects of differing nutrition resulting from population density during summer on body condition and reproduction. Thus, summer is a critical period for accumulation of body stores to buffer animals against winter; more emphasis should be placed on the role of spring and summer nutrition on population regulation in large, northern herbivores.},
  issn     = {1432-1939},
  doi      = {10.1007/s00442-004-1785-y},
  url      = {https://doi.org/10.1007/s00442-004-1785-y}
}

@article{taylor1981genetic,
  title    = {Genetic control of equilibrium maintenance efficiency in cattle},
  volume   = {33},
  url      = {http://journals.cambridge.org/article_S0003356100040617},
  abstract = {Twenty-two unmated female Ayrshire twin cattle, that had initially been maintained for prolonged periods on one of six constant feeding levels until an equilibrium weight was attained, were subsequently moved up to higher constant feeding levels including ad libitum. In all, results were obtained for 44 equilibrium periods mostly of 96 weeks duration.For controlled feeding levels, the log-log,. regression of equilibrium body weight on food intake, within animals, was 0·999 (s.e. 0·045). For all results, including mature equilibria, the within-animal regression was 1–014. There was thus no systematic change in an individual's equilibrium maintenance requirement per kg body weight in the range from 25\%, to 100\%, mature. Efficiency of food utilization for equilibrium maintenance was found to be independent of age also, except for a small increase at advanced ages beyond 8 to 9 years.There were significant differences between animals in equilibrium maintenance efficiency, the genetic coefficient of variation being 6·4\%. The most striking result, however, was a within-animal repeatability of 0·7, which meant that almost the same efficiency was re-attained when, after a prolonged period of many years on one constant feeding level, the same animal was allowed to re-establish a new equilibrium on a higher level.Following prolonged periods of food restriction, the animals showed remarkable capacity to recover in body weight even at very advanced ages, but nevertheless substantial stunting of mature weight did occur.},
  pages    = {179--194},
  number   = {2},
  journal  = {Animal Science},
  author   = {Taylor, C. S. and Turner, H. G. and Young, G. B.},
  year     = {1981}
}

@article{tollefson2010influence,
  author   = {Tollefson, Troy N. and Shipley, Lisa A. and Myers, Woodrow L. and Keisler, Duane H. and Dasgupta, Nairanjana},
  title    = {Influence of Summer and Autumn Nutrition on Body Condition and Reproduction in Lactating Mule Deer},
  journal  = {The Journal of Wildlife Management},
  volume   = {74},
  number   = {5},
  pages    = {974--986},
  keywords = {body condition, Insulin Growth Factor 1, intake, lactation, leptin, mule deer, nutrition, Odocoileus hemionus, pregnancy, reproduction},
  doi      = {10.2193/2008-529},
  url      = {https://wildlife.onlinelibrary.wiley.com/doi/abs/10.2193/2008-529},
  eprint   = {https://wildlife.onlinelibrary.wiley.com/doi/pdf/10.2193/2008-529},
  abstract = {Recent work suggests that availability and quality of forage in late summer and early autumn, a time when female ungulates face multiple energetic demands, is critical to reproduction in wild ungulates. Therefore, we examined direct links between nutritional quality of diets, body condition, and reproduction of lactating mule deer. Using captive mule deer, we tested the hypothesis that females consuming diets with lower digestible energy (DE; kJ/g) would have lower DE intake rates (DEI; MJ/day), have less body fat and muscle, have later estrus cycles, and have lower pregnancy and twinning rates. Deer fed lower DE diets had lower DEI during summer and autumn. In turn, deer with lower DEI, regardless of diet DE, had lower body mass, body fat, and muscle thickness. When nutritional quality of diets began to decline earlier in the summer, relationships between food quality, DEI, and body condition were stronger. Although DEI did not influence estrus date for deer that became pregnant before 21 December, deer with lower DEI had a lower probability of becoming pregnant and had a lower probability of producing twins. Measures of body condition in October (i.e., body mass, body fat, and muscle depth) predicted pregnancy and twinning rates in mule deer. Serum concentration of hormones leptin and Insulin Growth Factor 1 were not good predictors of body condition or reproduction. These findings suggest that managers concerned with productivity of mule deer populations should consider focusing on assessing and improving quality of forage available in summer and autumn.},
  year     = {2010}
}

@article{torbit1988calibration,
  ISSN      = {0022541X, 19372817},
  URL       = {https://doi.org/10.2307/3800911},
  abstract  = {We measured total body fat (TBF), kidney fat index (KFI), and femur marrow fat (FMF) of 24 adult female and 32 fawn mule deer (Odocoileus hemionus) collected in Piceance Basin, Colorado, during winters 1982-83 and 1983-84. All fat stores declined over winter in both age groups. For each age group, ln transformation of left, right, and mean KFI provided higher correlations with TBF than untransformed KFI. Either or both kidneys may be used to calculate KFI during fall through early spring, but data from adult females and fawns should not be combined. Femur marrow fat correlated with ln TBF in both age groups. However, FMF did not predict TBF as well as KFI because the most rapid change in FMF occurred at low percentages of TBF.},
  author    = {Stephen C. Torbit and Len H. Carpenter and Richard M. Bartmann and A. William Alldredge and Gary C. White},
  journal   = {The Journal of Wildlife Management},
  number    = {4},
  pages     = {582--588},
  publisher = {[Wiley, Wildlife Society]},
  title     = {Calibration of Carcass Fat Indices in Wintering Mule Deer},
  volume    = {52},
  year      = {1988}
}

@article{vanlangevelde2008intantaneous,
  title    = {Instantaneous intake rate of herbivores as function of forage quality and mass: Effects on facilitative and competitive interactions},
  journal  = {Ecological Modelling},
  volume   = {213},
  number   = {3},
  pages    = {273--284},
  year     = {2008},
  issn     = {0304--3800},
  doi      = {https://doi.org/10.1016/j.ecolmodel.2007.12.009},
  url      = {http://www.sciencedirect.com/science/article/pii/S0304380007006485},
  author   = {Frank van Langevelde and Michael Drescher and Ignas M.A. Heitkönig and Herbert H.T. Prins},
  keywords = {Alternative stable states, Co-existence, Competition, Grazing, Facilitation, Forage intake, Forage quality, Lawn grass},
  abstract = {The functional response as the link between the consumer and its resource is a central issue in herbivore–vegetation interactions. Vegetation often consists of low and high quality tissue due to nutritional or structural differences. It has been observed that the instantaneous intake rate of herbivores decreases with decreasing forage quality. However, so far variation in forage quality is not explicitly considered when modeling this instantaneous intake rate. In this paper, we derive a model for the instantaneous intake rate depending on forage quality, i.e., the proportion of high quality tissue in the vegetation. In the model, a downward deflection of the functional response curve is caused by a reduction of the maximum consumption rate at high proportions of low quality tissue. The model gives a mechanistic explanation for decreasing intake rate with decreasing forage quality. Compared to a conventional functional response model with constant maximum consumption rate, a herbivore–grass model with the forage quality-dependent functional response leads to discontinuous changes in the vegetation and herbivore density. The effects hinge on the positive feedback between herbivore density and the proportion of high quality forage. Our analyses show that this positive feedback can explain the maintenance of lawn grass where a high herbivore density can maintain high quality forage. The model results indicate that depending on the coefficients of trophic conversion from resource to consumer, co-existence, facilitation and competitive exclusion between differently sized herbivore species can emerge.}
}

@phdthesis{vanwijngaarden1985elephants,
  title     = {Elephants-trees-grass-grazers. Relationships between climate, soils, vegetation and large herbivores in a semi-arid savanna ecosystem (Tsavo, Kenya)},
  author    = {van Wijngaarden, Willem},
  year      = {1985},
  publisher = {ITC},
  location  = {Enschede},
  eprint    = {http://library.wur.nl/WebQuery/wurpubs/fulltext/201467}
}

@article{wade1992metabolic,
  title    = {Metabolic fuels and reproduction in female mammals},
  journal  = {Neuroscience \& Biobehavioral Reviews},
  volume   = {16},
  number   = {2},
  pages    = {235--272},
  year     = {1992},
  issn     = {0149-7634},
  doi      = {https://doi.org/10.1016/S0149-7634(05)80183-6},
  url      = {http://www.sciencedirect.com/science/article/pii/S0149763405801836},
  author   = {George N. Wade and Jill E. Schneider},
  keywords = {Estrous cycles, Menstrual cycles, Ovulation, Estrous behavior, Luteinizing hormone, Lactation, Gonadotropin-releasing hormone, Maternal behavior, Estradiol, Progesterone, Food intake, Exercise, Thermoregulation, Adipose tissue, Energy balance, Metabolic fuels},
  abstract = {A complete reproductive cycle of ovulation, conception, pregnancy, and lactation is one of the most energetically expensive activities that a female mammal can undertake. A reproductive attempt at a time when calories are not sufficiently available can result in a reduced return on the maternal energetic investment or even in the death of the mother and her offspring. Numerous physiological and behavioral mechanisms link reproduction and energy metabolism. Reproductive attempts may be interrupted or deferred when food is scarce or when other physiological processes, such as thermoregulation or fattening, make extraordinary energetic demands. Food deprivation suppresses both ovulation and estrous behavior. The neural mechanisms controlling pulsatile release of gonadotropin-releasing hormone (GnRH) and, consequently, luteinizing hormone secretion and ovarian function appear to respond to minute-to-minute changes in the availability of metabolic fuels. It is not clear whether GnRH-secreting neurons are able to detect the availability of metabolic fuels directly or whether this information is relayed from detectors elsewhere in the brain. Although pregnancy is less affected by fuel availability, both lactational performance and maternal behaviors are highly responsive to the energy supply. When a reproductive attempt is made, changes in hormone secretion have dramatic effects on the partitioning and utilization of metabolic fuels. During ovulatory cycles and pregnancy, the ovarian steroids, estradiol and progesterone, induce coordinated changes in the procurement, ingestion, metabolism, storage, and expenditure of metabolic fuels. Estradiol can act in the brain to alter regulatory behaviors, such as food intake and voluntary exercise, as well as adenohypophyseal and autonomic outputs. At the same time, ovarian hormones act on peripheral tissues such as adipose tissue, muscle, and liver to influence the metabolism, partitioning and storage of metabolic fuels. During lactation, the peptide hormones, prolactin and growth hormone, rather than estradiol and progesterone, are the principal hormones controlling partitioning and utilization of metabolic fuels. The interactions between metabolic fuels and reproduction are reciprocal, redundant, and ubiquitous; both behaviors and physiological processes play vital roles. Although there are species differences in the particular physiological and behavioral mechanisms mediating nutrition-reproduction interactions, two findings are consistent across species: 1) Reproductive physiology and behaviors are sensitive to the availability of oxidizable metabolic fuels. 2) When reproductive attempts are made, ovarian hormones play a major role in the changes in ingestion, partitioning, and utilization of metabolic fuels.}
}

@article{weiner1973dressing,
  title   = {Dressing percentage, gross body composition and caloric value of roe-deer},
  author  = {Weiner, January},
  journal = {Acta Theriologica},
  volume  = {18},
  pages   = {209--222},
  month   = {08},
  year    = {1973}
}

@article{wickham2014tidy,
  author   = {Hadley  Wickham},
  title    = {Tidy Data},
  journal  = {Journal of Statistical Software, Articles},
  volume   = {59},
  number   = {10},
  year     = {2014},
  abstract = {A huge amount of effort is spent cleaning data to get it ready for analysis, but there has been little research on how to make data cleaning as easy and effective as possible. This paper tackles a small, but important, component of data cleaning: data tidying. Tidy datasets are easy to manipulate, model and visualize, and have a specific structure: each variable is a column, each observation is a row, and each type of observational unit is a table. This framework makes it easy to tidy messy datasets because only a small set of tools are needed to deal with a wide range of un-tidy datasets. This structure also makes it easier to develop tidy tools for data analysis, tools that both input and output tidy datasets. The advantages of a consistent data structure and matching tools are demonstrated with a case study free from mundane data manipulation chores.},
  issn     = {1548-7660},
  pages    = {1--23},
  doi      = {10.18637/jss.v059.i10},
  url      = {https://www.jstatsoft.org/v059/i10}
}

@article{zhu2018large,
  author   = {Zhu, Dan and Ciais, Philippe and Chang, Jinfeng and Krinner, Gerhard and Peng, Shushi and Viovy, Nicolas and Pe{\~n}uelas, Josep and Zimov, Sergey},
  title    = {The large mean body size of mammalian herbivores explains the productivity paradox during the Last Glacial Maximum},
  journal  = {Nature Ecology \& Evolution},
  year     = {2018},
  abstract = {Large herbivores are a major agent in ecosystems, influencing vegetation structure, and carbon and nutrient flows. During the last glacial period, a mammoth steppe ecosystem prevailed in the unglaciated northern lands, supporting a high diversity and density of megafaunal herbivores. The apparent discrepancy between abundant megafauna and the expected low vegetation productivity under a generally harsher climate with a lower CO2 concentration, termed the productivity paradox, requires large-scale quantitative analysis using process-based ecosystem models. However, most of the current global dynamic vegetation models (DGVMs) lack explicit representation of large herbivores. Here we incorporated a grazing module in a DGVM based on physiological and demographic equations for wild large grazers, taking into account feedbacks of large grazers on vegetation. The model was applied globally for present-day and the Last Glacial Maximum (LGM). The present-day results of potential grazer biomass, combined with an empirical land-use map, infer a reduction in wild grazer biomass by 79-93\% owing to anthropogenic land replacement of natural grasslands. For the LGM, we find that the larger mean body size of mammalian herbivores than today is the crucial clue to explain the productivity paradox, due to a more efficient exploitation of grass production by grazers with a large body size.},
  issn     = {2397-334X},
  doi      = {10.1038/s41559-018-0481-y},
  url      = {https://doi.org/10.1038/s41559-018-0481-y}
}