Sites with high environmental suitability for species’ occurrence, in terms of abiotic conditions, may hold populations with higher local abundances by increasing reproductive and survival rates and decreasing extinction rate. Interspecific competition, however, may affect this relationship. Here we tested the hypothesis that local abundance of the gray slender opossum Marmosops incanus is affected by the local richness of potential competitors and environmental suitability derived from ecological niche models (ENMs). We also discuss the ability of distinct modelling methods to predict species’ abundance. We compiled occurrence records and information about M. incanus’ relative abundance from museums and published articles. Environmental suitability was derived from five algorithms using seven environmental predictors. To assess our hypothesis, we chose the best statistical models among generalised linear models and quantile regressions, and then tested whether the effects of richness of competitors on local abundance are stronger under highly suitable conditions. We found that environmental suitability given by presence‐only methods are positively related to the maximum abundance of M. incanus. That is, species’ local abundance is low when suitability is low but can be either low or high when suitability is high. The richness of competitors, in turn, explains the abundance variation within sites with high environmental suitability. We strongly recommend that the relationship between abundance and suitability must be carefully interpreted when using ENMs to predict species’ distribution because biotic interactions can be the main driver of local abundance within highly suitable environments.

中文翻译：

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种间竞争在高度合适的地区限制了当地的丰富度

就非生物条件而言，对物种的发生具有高度环境适应性的地点，可能会通过提高繁殖和存活率以及降低灭绝率来保持本地丰度更高的种群。种间竞争可能会影响这种关系。在这里，我们测试了以下假设：灰色细长负鼠Marmosops incanus的局部丰度受到潜在竞争者的局部富裕程度以及源自生态位模型（ENM）的环境适应性的影响。我们还讨论了不同的建模方法预测物种丰度的能力。我们收集了有关印度支原体的发生记录和信息博物馆和已发表文章的相对丰富。环境适应性来自使用七个环境预测器的五种算法。为了评估我们的假设，我们在广义线性模型和分位数回归中选择了最佳的统计模型，然后测试了竞争者的丰富度对本地丰度的影响在高度合适的条件下是否更强。我们发现，仅存在方法所提供的环境适应性与印加支原体的最大丰度呈正相关。也就是说，当适应性低时，物种的局部丰度低，但是当适应性高时，物种的局部丰度可以低或高。反过来，竞争者的丰富性也解释了具有高环境适应性的站点内的丰度变化。我们强烈建议在使用ENM预测物种分布时必须仔细解释丰度与适应性之间的关系，因为在高度适合的环境中生物相互作用可能是局部丰度的主要驱动力。