Comparative responses of spiders and plants to maritime heathland restoration

Abstract

Assessment of habitat restoration often rely on single-taxa approach, plants being widely used. Arthropods might yet complement such evaluation, especially in hard, poorly-diversified environments such as maritime clifftops. In this study we compared the responses of spiders and plants (both at species and assemblage levels) to increasing time of heathland restoration. Sampling took place in different sites of Brittany (Western France), using a replicated design of both pitfall traps and phytosociological relevés. A total of 5056 spiders belonging to 160 species, and 103 plant species were found. No change in species richness between degradation states was found for spiders. Plant species richness was lower in highly degraded habitats of recently restored sites but was not in the oldest restored one. Species composition greatly changed through turnover mechanisms between all sites and degradation states, for both spider and vegetation. Heterogeneity was higher in references states, and increased over restoration time between sites. The number of indicator species decreased with restoration age for spiders, while no indicator species was found for plants. Restoration is still ongoing after 15 years, with no recovery of reference assemblages for both plants and spiders, but there were some signals toward reference in the oldest restoration site. Plants and spiders were proved to be complementary bio-indicators of post disturbance restoration, as they bring different, scaledependent information on restoration success.

Drivers of taxonomic, functional and phylogenetic diversities in dominant ground-dwelling arthropods of coastal heathlands

“…These sites were selected for they are all comparable with similar dominant vegetation (a short and dry heathland dominated by Erica spp . and Ulex spp ), and under ongoing ecological passive restoration with 3 degradation states by site (see full description of study sites and pictures in Hacala et al 2020).…”

“…Environmental variables where inferred from the vegetation communities using Ellenberg's index values (1992) extracted from Hill et al (2004) and corrected for the British Isles. Anthropogenic degradation was assessed by using bare ground as a proxy of degradation intensity (Hacala et al 2020). Pitfall samples were sorted in laboratory, arthropods transferred to ethanol 70°, and stored at the University of Rennes 1.…”

“…We studied three groups of arthropods, spiders, ground beetles and ants. These arthropods are known to complement vegetation survey (Pétillon et al 2014; Hacala et al 2020), and thereby offer an interesting opportunity to better understand the link between PD and FD (Wong et al 2019). Spiders, ants and ground beetles are dominant ground-active macro-arthropods in several temperate habitats, and their traits and phylogeny are relatively well known (Bond et al 2014; Pedley et al 2014; Schirmel et al 2016; Magura 2016; Parr et al 2017).…”

Relative Efficiency of Pitfall vs. Bait Trapping for Capturing Taxonomic and Functional Diversities of Ant Assemblages in Temperate Heathlands

“…La Pointe de l'Enfer (S2) (47°37'18.3"N 3°27'46.9"W) was degraded by frequent vehicle access and human trampling. L'Apothicairerie (S3) (47°21'44.0" N, 3°15'34.9" W) was heavily degraded by infrastructures (car park and hotel) that were removed in 2012 (see Hacala et al, 2020 for a full description, and pictures, of the sampling sites).…”

Spider Community Variability and Response to Restoration in Arid Grasslands of the Pacific Northwest, USA

“…Studies in other parts of the world that have assessed how grassland restoration affects spiders found mixed results. For example, while multiple studies have found that grassland restoration affects spider abundance, richness, and diversity [ 21 , 28 , 29 , 30 , 31 ], the direction of effects vary, with some studies finding positive effects and others finding negative ones. Other studies have found no effect of restoration on spider abundance, richness, and diversity [ 28 , 30 , 32 , 33 , 34 ].…”