Gastropod communities in alpine grasslands are characterized by high beta diversity

Abstract

Alpine grasslands harbour species-rich communities of plants and invertebrates. We examined how environmental variables and anthropogenic impact shape species richness and community structure of terrestrial gastropods in alpine grasslands in the Val Müstair (Eastern Alps, Switzerland). Gastropods were sampled using a standardised method at 76 sites spanning an elevation range from 1430 m to 2770 m. A total of 4763 specimens representing 52 species were recorded. Correspondence analysis based on presence/absence data revealed that the grassland gastropod community was structured in a complex way with elevation, wetness, grazing intensity and inclination of the sites as key factors, while abundance-based analysis identified the importance of the elevation and wetness of sites. Generalized linear model showed that species richness decreased with increasing elevation and increased with increasing soil pH. The grassland gastropod communities were characterized by a high beta diversity, as indicated by the SDR-simplex analysis. Species-specific traits of gastropods showed sensitivity to the environmental characters of the sites, as shown by a fourth-corner analysis. Nomenclature: Turner et al. (1998)Abbreviations: AIC-Akaike's Information Criterion; CA-Correspondence analysis; GLM-Generalized linear model.

Conservation at a slow pace: terrestrial gastropods facing fast-changing climate

“…Even if knowledge is still too scarce to conclude undoubtedly, only the smallest species seem able to survive extreme cold temperatures during winter. This hypothesis is supported by several studies offering evidence that land snail communities are less diverse at high altitudes and latitudes, where small taxa become more frequent ( Hausdorf and Hennig, 2003 ; Nekola et al ., 2013 ; Baur et al ., 2014 ; Horsák and Chytry, 2014 ; Schmera and Baur, 2014 ; Forsyth and Oldham, 2016 ). With climate warming, we would expect the gastropod community to become richer in bigger species, with consequences for competition, trophic webs, vegetation grazing and soil dynamics.…”

Higher Elevations Tend to Have Higher Proportion of Plant Species With Glandular Trichomes

“…Unfortunately, we did not have herbivory or distribution data for mollusks in our study areas. Studies conducted at other sites have found that gastropod diversity generally decreased with increasing elevation (e.g., Liew et al, 2010;Baur et al, 2014;Schmera and Baur, 2014). If such pattern is true for the Hengduan Mountains region, higher proportion of species with glandular trichomes at higher elevations is unlikely to relate to herbivory pressure from mollusks in our study area.…”

Beer, brains, and brawn as tools to describe terrestrial gastropod species richness on a montane landscape

“…Although higher species richness at lower elevations is not surprising (Baur et al. , Schmera and Baur ), we must interpret this result with some caution. We generally surveyed lower elevation sites earlier in the season as snowpack prevented access to higher elevation sites until late season hotter and drier weather prevailed.…”