Searcy Christopher A, Shaffer H Bradley
Am Nat. 2016 Apr;187(4):423-35. doi: 10.1086/685387. Epub 2016 Feb 22.
Defining species' niches is central to understanding their distributions and is thus fundamental to basic ecology and climate change projections. Ecological niche models (ENMs) are a key component of making accurate projections and include descriptions of the niche in terms of both response curves and rankings of variable importance. In this study, we evaluate Maxent's ranking of environmental variables based on their importance in delimiting species' range boundaries by asking whether these same variables also govern annual recruitment based on long-term demographic studies. We found that Maxent-based assessments of variable importance in setting range boundaries in the California tiger salamander (Ambystoma californiense; CTS) correlate very well with how important those variables are in governing ongoing recruitment of CTS at the population level. This strong correlation suggests that Maxent's ranking of variable importance captures biologically realistic assessments of factors governing population persistence. However, this result holds only when Maxent models are built using best-practice procedures and variables are ranked based on permutation importance. Our study highlights the need for building high-quality niche models and provides encouraging evidence that when such models are built, they can reflect important aspects of a species' ecology.
定义物种的生态位对于理解它们的分布至关重要，因此对于基础生态学和气候变化预测来说是根本性的。生态位模型（ENMs）是做出准确预测的关键组成部分，包括根据响应曲线和变量重要性排名对生态位的描述。在本研究中，我们通过询问这些相同的变量是否也基于长期种群统计学研究来控制年度补充量，评估了Maxent根据环境变量在划定物种分布范围边界方面的重要性所做的排名。我们发现，基于Maxent对加利福尼亚虎螈（Ambystoma californiense；CTS）分布范围边界设定中变量重要性的评估，与这些变量在种群水平上控制CTS持续补充量的重要性高度相关。这种强相关性表明，Maxent对变量重要性的排名捕捉到了对控制种群持续性因素的生物学现实评估。然而，只有当使用最佳实践程序构建Maxent模型并基于排列重要性对变量进行排名时，这一结果才成立。我们的研究强调了构建高质量生态位模型的必要性，并提供了令人鼓舞的证据，即当构建这样的模型时，它们可以反映物种生态学的重要方面。
