Abstract The “resource availability hypothesis” predicts occurrence of larger rodents in more productive habitats. This prediction was tested in a dataset of 1,301 rodent species. We used adult body mass as a measure of body size and normalized difference vegetation index (NDVI) as a measure of habitat productivity. We utilized a cross-species approach to investigate the association between these variables. This was done at both the order level (Rodentia) and at narrower taxonomic scales. We applied phylogenetic generalized least squares (PGLS) to correct for phylogenetic relationships. The relationship between body mas and NDVI was also investigated across rodent assemblages. We controlled for spatial autocorrelation using generalized least squares (GLS) analysis. The cross-species approach found extremely low support for the resource availability hypothesis. This was reflected by a weak positive association between body mass and NDVI at the order level. We find a positive association in only a minority of rodent subtaxa. The best fit GLS model detected no significant association between body mass and NDVI across assemblages. Thus, our results do not support the view that resource availability plays a major role in explaining geographic variation in rodent body size.

中文翻译：

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栖息地生产力不能很好地预测啮齿动物的体型

摘要 “资源可用性假设”预测在生产力更高的栖息地中会出现更大的啮齿动物。该预测在 1,301 种啮齿动物物种的数据集中进行了测试。我们使用成年体重作为体型的衡量标准，使用归一化差异植被指数 (NDVI) 作为栖息地生产力的衡量标准。我们利用跨物种方法来研究这些变量之间的关联。这是在订单级别（啮齿类动物）和更窄的分类尺度上完成的。我们应用系统发育广义最小二乘法 (PGLS) 来校正系统发育关系。还研究了啮齿动物组合中体重和 NDVI 之间的关系。我们使用广义最小二乘 (GLS) 分析控制空间自相关。跨物种方法发现对资源可用性假设的支持极低。这反映在体重和 NDVI 在订单水平上的弱正相关。我们仅在少数啮齿动物亚类中发现了正相关。最佳拟合 GLS 模型检测到不同组合的体重和 NDVI 之间没有显着关联。因此，我们的结果不支持资源可用性在解释啮齿动物体型的地理变化方面起主要作用的观点。