Impact of small-scale conservation management methods on spider assemblages in xeric grassland

Abstract

Seminatural grasslands are among the most valuable habitats for arthropod conservation in Central Europe. The abandonment of traditional farming has caused these areas to become overgrown and homogeneous, thereby resulting in loss of arthropod biodiversity. This traditional farming therefore needs to be complemented by active conservation management methods. An important question is whether small-scale conservation management may support arthropod diversity and habitat specialists inhabiting abandoned seminatural grasslands. We investigated the effects of mowing, prescribed burning, mechanical turf disturbance, and absence of active management on species richness, functional diversity and composition, conservation value, abundance of Red List species, and assemblage composition of spiders. The management methods were applied on small-scale (4 × 5 m) patches in protected xeric grassland. Spiders were sampled using pitfall traps and sweeping during 2017 and 2018. A total of 11,634 specimens from 154 species were recorded, including many rare and threatened species. The temporal responses of spider assemblages to active conservation management depended on the particular group of spiders. Changes in assemblage composition and resulting shifts in the community weighted mean values were distinct in the second year of the experiment. Management had no significant effect on the species richness of grounddwelling spiders. Mechanical turf disturbance shifted the assemblage composition of grounddwelling spiders towards habitat generalist species. Vegetation-dwelling spiders had the highest species richness in unmanaged patches. Their functional diversity was lower in disturbed patches. Burnt patches supported species of conservation concern for both spider groups. Prescribed burning had positive results for most of the studied indicators.Nevertheless, mechanical turf disturbance had a rather negative effect on the spider assemblages. Our results indicate that even small, patch-like interventions with minimal costs 3 can considerably support the valuable spider assemblages of xeric grassland in the intensified landscape of Central Europe.

No detrimental effects of soil disturbance resulting from grassland restoration operations on aboveground‐dwelling invertebrate communities

“…For both ground beetle and spider communities, we noted a slight increase in humidity preference in the plowed treatments, indicating a wetter habitat after restoration. A similar trait shift of spiders towards wetter habitats has also been observed 1 year after soil disturbance in xeric grasslands (Hamřík & Košulič 2021). Given that in the context of restoration of degraded grasslands, soil disturbance occurs only once at the onset, just prior to seed addition, we assume that, in the years to come, the habitat preference indices will return towards values found in the undisturbed control meadows.…”

Plant-dwelling spider communities of three developmental phases in primeval oak-lime-hornbeam forest in the Białowieża National Park, Poland

“…Our assumption was based on the findings of many authors who show that complex and structurally diverse habitats, providing a broad spectrum of niches, promote species diversity of spiders (e.g., Malumbres-Olarte et al 2013;St. Pierre & Kovalenko 2014;Áviala et al 2017;Hamřik & Košulič 2021).…”

Spider Assemblages of Tree Branches in Managed and Primeval Deciduous Stands of the Białowieża Forest

“…This difference was particularly visible in the hummock-hollow structure of alder carr, where trees growing in primeval stands of this type of forest were older and larger, and thus the hummocks created by their roots provided more space and shelter for spiders. Many authors have shown that structurally diverse and complex habitats favor higher species diversity of spiders as a result of providing a broad spectrum of niches [46][47][48][49].…”