Harvestmen (Opiliones) community structure varies across forest-meadow ecotones in a biodiverse karst region

Abstract

The positive effects of habitat heterogeneity on biodiversity are well established, but it is unclear how the diversity of less frequently studied but ecologically important taxa such as harvestmen (Opiliones) may vary across habitat boundaries generated by fine-scale traditional land-use. We investigated how harvestmen community metrics (composition, abundance, and diversity) varied across forest-meadow ecotones in a protected and naturally highly biodiverse karst region where biodiversity conservation plays an important role. We sampled harvestmen across forest edges adjacent to hay meadows in the Veľka Fatra Mts. (Central Slovakia) during two vegetation seasons using pitfall traps. In total, 13 species from 4 families were collected. The total number of captured harvestmen was greatest in forests and lowest in meadows and species composition varied between these two habitats (with forest edges forming a transitional community). Species diversity (exponential of Shannon’s H´) was marginally greater within forest edges compared to forest and meadow habitats. Harvestmen epigeic activity-density (an abundance proxy) was correlated positively with tree canopy cover, and negatively with the cover of herbaceous layer. Our findings have implications for biodiversity conservation as they highlight the importance of forest habitats for the conservation of understudied taxa such as harvestmen in heterogenous landscapes modified by humans.