Management is more important than urban landscape parameters in shaping orthopteran assemblages across green infrastructure in a metropole

Abstract

Urbanisation significantly shapes species abundance, diversity, and community structure of invertebrate taxa but the impact on orthoptera remains widely understudied. We investigated the combined effects of spatial, urban landscape and management-related parameters. Additionally, we discussed different sampling strategies. We sampled orthopteran assemblages on green infrastructure associated with the public transport system of Vienna, Austria. Sampled areas include railroad embankments, recreational areas or fallows. Using LMs, (G)LMMs and nMDS, we compared quantitative sampling using transect counts and semi-quantitative sampling which also included observations made off-transects. We found that vegetation type was the most important parameter, whereby structure-rich fallows featured highest species diversities and, together with extensive meadows, highest abundances, while intensive lawns were less suitable habitats. The semi-quantitative data set revealed an underlying species-area-relationship (SAR). Other important but highly entangled parameters were the mowing intensity, vegetational heterogeneity and cover of built-up area in a 250 m radius. Most found species have high dispersal abilities. Urban assemblages are most significantly shaped by management-related parameters on the site itself, which highlights the potential of conservation efforts in urban areas through suitable management. Sites of different vegetation types differ greatly and need adjusted management measures. Urban landscape parameters, such as the degree of soil sealing, appeared less important, likely due to the high dispersal abilities of most observed orthoptera species. The indicated species-area-relationship could be used to prioritize sites for conservation measures.