Mechanisms underlying biological diversities at different scales have received significant attention over the last decades. The hypothesis of whether local abiotic factors, driving functional and phylogenetic diversities, can differ among taxa of arthropods remains under-investigated. In this study, we compared correlations and drivers of functional diversity (FD) and phylogenetic diversity (PD) between spiders and carabids, two dominant taxa of ground-dwelling arthropods in salt marshes. Both taxa exhibited high correlation between FD and PD; the correlation was even higher in carabids, probably owing to their lower species richness. Analyses using structural equation modelling highlighted that FD and PD were positively linked to taxonomic diversity (TD) in both taxa; however, abiotic factors driving the FD and PD differed between spiders and carabids. Salinity particularly drove the TD of carabids, but not that of spiders, suggesting that spiders are phenotypically more plastic and less selected by this factor. Conversely, PD was influenced by salinity in spiders, but not in carabids. This result can be attributed to the different evolutionary history and colonization process of salt marshes between the two model taxa. Finally, our study highlights that, in taxa occupying the same niche in a constrained habitat, FD and PD can have different drivers, and thereby different filtering mechanisms.

在过去的几十年里，不同尺度的生物多样性的潜在机制受到了广泛的关注。关于驱动功能和系统发育多样性的局部非生物因素在节肢动物类群之间是否存在差异的假设仍有待研究。在这项研究中，我们比较了蜘蛛和步甲（盐沼中陆地节肢动物的两个主要类群）之间功能多样性（FD）和系统发育多样性（PD）的相关性和驱动因素。两个类群都表现出 FD 和 PD 之间的高度相关性；步甲类的相关性甚至更高，可能是因为它们的物种丰富度较低。使用结构方程模型进行的分析强调，FD 和 PD 与两个类群的分类多样性 (TD) 呈正相关。然而，驱动 FD 和 PD 的非生物因素在蜘蛛和步甲动物之间是不同的。盐度尤其影响步甲动物的 TD，但不会影响蜘蛛的 TD，这表明蜘蛛在表型上更具可塑性，并且较少受此因素的选择。相反，蜘蛛的 PD 受盐度影响，但步甲类则不受盐度影响。这一结果可归因于两个模式类群之间不同的进化历史和盐沼定植过程。最后，我们的研究强调，在受限栖息地中占据相同生态位的类群中，FD 和 PD 可能具有不同的驱动因素，从而具有不同的过滤机制。