Barela Isidro, Burger Leslie M, Taylor Jimmy, Evans Kristine O, Ogawa Ryo, McClintic Lance, Wang Guiming
Department of Wildlife, Fisheries and Aquaculture Mississippi State University Mississippi State MS USA.
Siskiyou County Department of Agriculture Yreka CA USA.
Ecol Evol. 2020 Apr 12;10(11):4867-4875. doi: 10.1002/ece3.6239. eCollection 2020 Jun.
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 (), 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.
空间分布和栖息地选择是动物生态学研究的重要组成部分。栖息地选择可以优化个体的适应性。哈钦森生态位理论认为，物种的基础生态位能够支持种群的持续存在或增长。尽管基于生态位的物种分布模型（SDMs）和栖息地适宜性模型（HSMs），如最大熵模型（Maxent），已显示出较好到极佳的预测能力，但很少有研究将HSMs的预测与种群统计学率联系起来。我们旨在检验哈钦森生态位理论的预测，即栖息地适宜性（即出现的可能性）与北美半水生、食草、栖息地泛化种美洲河狸（Castor canadensis）的存活率呈正相关。我们还检验了理想自由分布的预测，即在平衡状态下动物的适应性或其替代指标与栖息地适宜性无关。我们使用Barker模型和2011年1月至2012年4月在美国阿拉巴马州北部收集的无线电遥测数据，估计了河狸的月存活概率。利用从2011年国家土地覆盖数据库（30米分辨率）导出的景观变量，通过Maxent为整个研究地点生成了栖息地适宜性地图。我们发现栖息地适宜性指数与河狸存活率之间呈负相关，这与生态位理论和理想自由分布的预测相矛盾。此外，美洲河狸选择的四个景观变量并不能预测存活率。我们研究地点的河狸种群已经存在了20年或更长时间，随后可能正在接近或已经达到承载能力。Maxent预测的栖息地利用增加以及随后的种内竞争可能降低了河狸的存活率。栖息地适宜性与适应性之间的关系可能很复杂，部分取决于当地动物的数量。未来需要开展结合当地数量和种群统计学率的机制性SDMs研究。
