Search USGS⌕ Search
Home/Archive/USGS

USGS · 70229346

Body size and digestive system shape resource selection by ungulates: A cross-taxa test of the forage maturation hypothesis

Saeideh Esmaeili·Brett R. Jesmer·Shannon E. Albeke·Ellen O. Aikens·Kathryn A. Schoenecker·Sarah R.B. King·Briana Abrahms·Buuveibaatar Bayarbaatar·Jeffrey L. Beck·Randall Boone·Francesca Cagnacci·Simon Chamaillé-Jammes·Buyanaa Chimeddorj·Paul C. Cross·Nandintsetseg Dejid·Jagdag Enkhbyar·Ilya Fischhoff·Adam T. Ford·Kate Jenks·Mahmoud-Reza Hemami·Jacob D. Hennig·Takehiko Y. Ito·Petra Kaczensky·Matthew J. Kauffman·John D. C. Linnell·Badamjav Lkhagvasuren·John F. McEvoy·Joerg Melzheimer·Jerod A. Merkle·Thomas Mueller·Jeff Muntifering·Atle Mysterud·Kirk A. Olson·Manuela Panzacchi·John Payne·Luca Pedrotti·Geir R. Rauset·Daniel I. Rubenstein·Hall Sawyer·John D. Scasta·Johannes Signer·Melissa Songer·Jared A. Stabach·Seth Stapleton·Olav Strand·Siva R. Sundaresan·Dorj Usukhjargal·Ganbold Uuganbayar·John Fryxell·Jacob R. Goheen
View original source ↗Export metadata ↓

Abstract

The forage maturation hypothesis (FMH) states that energy intake for ungulates is maximised when forage biomass is at intermediate levels. Nevertheless, metabolic allometry and different digestive systems suggest that resource selection should vary across ungulate species. By combining GPS relocations with remotely sensed data on forage characteristics and surface water, we quantified the effect of body size and digestive system in determining movements of 30 populations of hindgut fermenters (equids) and ruminants across biomes. Selection for intermediate forage biomass was negatively related to body size, regardless of digestive system. Selection for proximity to surface water was stronger for equids relative to ruminants, regardless of body size. To be more generalisable, we suggest that the FMH explicitly incorporate contingencies in body size and digestive system, with small-bodied ruminants selecting more strongly for potential energy intake, and hindgut fermenters selecting more strongly for surface water.

Explore related subjects

Ecology LettersArticle

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Saeideh Esmaeili, Brett R. Jesmer, Shannon E. Albeke, Ellen O. Aikens, Kathryn A. Schoenecker, Sarah R.B. King, Briana Abrahms, Buuveibaatar Bayarbaatar, Jeffrey L. Beck, Randall Boone, Francesca Cagnacci, Simon Chamaillé-Jammes, Buyanaa Chimeddorj, Paul C. Cross, Nandintsetseg Dejid, Jagdag Enkhbyar, Ilya Fischhoff, Adam T. Ford, Kate Jenks, Mahmoud-Reza Hemami, Jacob D. Hennig, Takehiko Y. Ito, Petra Kaczensky, Matthew J. Kauffman, John D. C. Linnell, Badamjav Lkhagvasuren, John F. McEvoy, Joerg Melzheimer, Jerod A. Merkle, Thomas Mueller, Jeff Muntifering, Atle Mysterud, Kirk A. Olson, Manuela Panzacchi, John Payne, Luca Pedrotti, Geir R. Rauset, Daniel I. Rubenstein, Hall Sawyer, John D. Scasta, Johannes Signer, Melissa Songer, Jared A. Stabach, Seth Stapleton, Olav Strand, Siva R. Sundaresan, Dorj Usukhjargal, Ganbold Uuganbayar, John Fryxell, Jacob R. Goheen. 2021-07-26. Body size and digestive system shape resource selection by ungulates: A cross-taxa test of the forage maturation hypothesis. https://doi.org/10.1111/ele.13848

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

Mixed support for the temperature-size rule in wild freshwater fishes

The temperature-size rule states that species living in warmer temperatures will grow faster and mature earlier at smaller sizes. While several studies have documented patterns in average body size consistent with the temperature-size rule in wild populations, a comprehensive test is lacking. Here, we use age and length data of 1.4 million fish across 7 species from 2704 lakes to quantify temperature-related variation in growth across ontogeny. Our results show that no species fully conforms to the temperature-size rule; despite patterns of juvenile growth rate and age at maturity typically aligning with the temperature-size rule, these changes seldom translate to reduced size at maturity or maximum size. We also found evidence that faster life histories in warmer environments are associated with reduced lifespans. A deeper understanding of how temperature shapes growth in natural systems is needed to accurately predict the effects of global warming on wildlife.

Illinois, Indiana, Iowa,Michigan, Minnesota, South↗
USGS2026

Waterfowl move less in heterogeneous and human-populated landscapes, with implications for spread of avian influenza viruses

Animal movements contribute to the spread of infectious diseases and are driven in part by environmental conditions. We investigated the links among the environment, animal movement, and infectious disease dynamics in waterfowl, which are among the primary wildlife hosts of avian influenza viruses. By combining telemetry data on 4606 individuals from 26 waterfowl species with data on land cover, weather, and vegetation, we found that waterfowl moved less in areas of higher land cover heterogeneity and higher human population density. Moreover, predicted waterfowl movement distances were weakly but positively correlated with distances between detections of H5N1 highly pathogenic avian influenza in wild waterfowl, suggesting that environmental conditions might contribute to the spread of this disease via their effects on bird movements. By considering wildlife movements alongside other drivers of infectious disease dynamics, such as livestock production and human mobility, we move closer to predicting outbreaks and informing interventions.

Ecology Letters↗
USGS2026

Linking community-climate disequilibrium to ecosystem function

Turnover in species composition often lags behind the pace of climate change, resulting in mismatches between climate and communities. However, the impact of these community-climate disequilibria on ecosystem functions is rarely considered, and current methods for measuring disequilibria assume that species ranges were, until recently, in equilibrium with climate. Here, we develop a simple theoretical model to address both of these problems by linking community-climate disequilibrium with ecosystem functioning. We show how disequilibrium can impair functioning in the near-term even when climate change is expected to enhance functioning in the long-term. Responses are most likely to change over time in communities where turnover is slow, the impact of disequilibrium counteracts the direct effects of climate on ecosystem function, and pre-existing disequilibrium is large. These findings emphasise the importance of precise and unbiased estimates of community-climate disequilibria for improving ecological forecasts. By fitting our model to time series of both climate and ecosystem function from a metacommunity simulation, we show the potential for community-climate disequilibrium to be inferred without direct knowledge about species' distributions or climatic tolerances. We end by outlining a research agenda to apply dynamic disequilibrium concepts and test novel hypotheses across diverse ecosystems.

Ecology Letters↗