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Spatial distribution and habitat selection are integral to the study of animal ecology. Habitat selection may optimize the fitness of individuals. Hutchinsonian niche theory posits the fundamental niche of species would support the persistence or growth of populations. Although niche‐based species distribution models (SDMs) and habitat suitability models (HSMs) such as maximum entropy (Maxent) have demonstrated fair to excellent predictive power, few studies have linked the prediction of HSMs to demographic rates. We aimed to test the prediction of Hutchinsonian niche theory that habitat suitability (i.e., likelihood of occurrence) would be positively related to survival of American beaver (Castor canadensis), a North American semi‐aquatic, herbivorous, habitat generalist. We also tested the prediction of ideal free distribution that animal fitness, or its surrogate, is independent of habitat suitability at the equilibrium. We estimated beaver monthly survival probability using the Barker model and radio telemetry data collected in northern Alabama, United States from January 2011 to April 2012. A habitat suitability map was generated with Maxent for the entire study site using landscape variables derived from the 2011 National Land Cover Database (30‐m resolution). We found an inverse relationship between habitat suitability index and beaver survival, contradicting the predictions of niche theory and ideal free distribution. Furthermore, four landscape variables selected by American beaver did not predict survival. The beaver population on our study site has been established for 20 or more years and, subsequently, may be approaching or have reached the carrying capacity. Maxent‐predicted increases in habitat use and subsequent intraspecific competition may have reduced beaver survival. Habitat suitability‐fitness relationships may be complex and, in part, contingent upon local animal abundance. Future studies of mechanistic SDMs incorporating local abundance and demographic rates are needed., We tested the hypothesis that increased habitat suitability would improve American beaver survival. On the contrary, American beaver survival was inversely related to habitat suitability index. Beaver survival was not related to the landscape variables selected by American beaver. Photo credits to “Stockphoto.com”.

Home range size of terrestrial animals may be influenced by spatiotemporal dynamics of resources. However, little is known regarding the effects of spatiotemporal resource availability on semi-aquatic central place foragers such as the American beaver Castor canadensis. From January 2011 to April 2012, 26 beavers at 11 wetlands at Redstone Arsenal in north-central Alabama, USA, were captured and radio-tracked using radio telemetry. The objectives of this study were to test the predictions of three hypotheses: (1) the resource dispersion hypothesis: more spatially dispersed resources throughout a landscape increase home range sizes; (2) the temporal resource variability hypothesis: more temporally variable resources result in decreases in home range sizes; (3) the habitat productivity hypothesis: increases in habitat productivity lead to decreases in home range sizes. Twenty-three of 26 radio-tagged beavers had well-bounded home ranges, and their home range sizes were positively related to the diversity of land cover within home ranges as predicted by the resource dispersion hypothesis. Furthermore, home range sizes of 26 beavers, including three seasonally dispersing beavers, decreased with increasing seasonal variability of within-home-range normalized difference vegetation index (NDVI), supporting the prediction of the resource heterogeneity hypothesis. Home range sizes of American beavers increased with increasing total NDVI and proportions of woody plant cover within home ranges probably to avoid overexploitation of woody plants. Our results suggest that the combination of resource quantity, spatial distribution and seasonal variation of resources influences movements and home ranges of central place foragers.

Physiological states and foraging behaviors may shape movement patterns of animals. Optimal foraging theory and what we term the deliberate movement hypothesis predict that, to reduce predation risk, central place foragers should move faster with smaller turning angles the further they are from their central place. The complementary bimodal foraging trip hypothesis predicts that the distribution of foraging distances exhibited by central place foragers should be bimodal due to a trade-off between provisioning offspring and self-feeding. We used radio-telemetry to test these hypotheses for American beavers (Castor canadensis) in northern Alabama, United States. American beavers moved faster with increasing distance from lodges in wetland land cover but not in terrestrial land covers, partially supporting the deliberate movement hypothesis. Hourly distances moved from lodges were distributed bimodally during the breeding season, which supports the bimodal foraging trip hypothesis. Therefore, central place foraging may be a determinant of movement characteristics of American beavers.