Habitat filtering differentially modulates phylogenetic and functional diversity relationships between predatory arthropods

Abstract

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.

Effects of environmental filtering on taxonomic and functional diversity patterns : When spiders and plants provide complementary information to water level management in the Seine estuary

“…These results suggest a weaker speci c selection on spider species compared to plant species on this site, possibly due to their higher mobility compared to sessile organisms (Lafage et al, 2015). The pattern of spider functional richness, similar to species richness, is consistent with the high correlation between these two metrics (Pavoine et al, 2013), supporting species selection based on functional characteristics, as previously observed for spiders in harsher environments (Ridel et al, 2021). Conversely, the similar functional richness of plants in the middle and low elevation zones, contrasting with previous results, suggests functional trait convergence among present species (Meinzer, 2003).…”

“…This supports lightly ltered spider assemblages (i.e. no exclusion of generalist species) compared to harsher environments (Pétillon et al, 2008;Ridel et al, 2021), which is consistent with the site's position furthest from the sea on the lateral gradient. For plants, taxonomic and functional diversity patterns did not signi cantly change with Q order on this site, suggesting a high turnover process (Yuan et al, 2012).…”

“…Conversely, plant species richness appeared higher in the middle zone, possibly linked to freshwater upwelling coupled with restrictions on tidal in uence, generating intermediate environmental conditions allowing the co-occurrence of different species types (i.e., halophilic and hygrophilous species). In terms of functionality, the spider pattern remained generally coherent with the taxonomic one, with minor differences observed between pairs of topographical zones but no shifting patterns (Pavoine et al, 2013;Ridel et al, 2021). In contrast to this result, plant diversity in the lower zone appeared to shift from lower taxonomic to intermediate functional richness values.…”

“…In many cases, spiders are neglected, even though their bioindication capacity is widely demonstrated (Pearce & Venier, 2006;Borchard et al, 2014). Additionally, they are present in high abundance in estuaries and are also able to indicate changes in ooding and salinity (Pétillon et al, 2003;Pétillon et al, 2014;Fournier et al, 2015;Ridel et al, 2021), but are still rarely used in this type of ecosystem (Desender & Maelfait, 1999;David et al, 2016). The coupled use of plants and spiders has the advantage of employing taxa from different trophic levels, exhibiting complementary responses to environmental changes (Lafage et al, 2015;Hacala et al, 2020).…”

Pannonic salt marshes – important habitats for ground-active spider communities

“…According to Zulka et al (1997), we recorded three halophilic species, Crustulina sticta (O. Pickard-Cambridge, 1861), Zelotes mundus (Kulczyński, 1897) and Argenna patula (Simon, 1874). Interestingly, Z. mundus has also recently been reported from salt marshes on the Atlantic coast of southwestern France (Ridel et al 2021). Two other species, Metopobactrus deserticola Loksa, 1981 (endemic of the Pannonian region) and Gnaphosa rufula , can be included in this group because they show a strong association to xerothermic saline habitats (Gajdoš et al 2019).…”