Differential effect of grassland mowing on arthropod taxa

Abstract

Arthropods face a global decline attributed to habitat loss, climate change, pesticide use, and an intensification of land-use practices such as mowing. Studies on the effects of mowing on arthropod abundance showed conflicting results potentially due to multiple factors, including study design, grassland management, sampling method, and arthropod taxon studied. We conducted four studies in different grasslands, including intensively and extensively used agricultural and urban grasslands, utilising sweep netting, suction sampling, and pitfall traps. We compared the mowing responses of arthropod taxa between those studies at three different taxonomic resolutions (first-level overall arthropods, second-level orders, and third-level families and suborders). First, we discovered that mowing had a negative effect on overall arthropod abundance in all our studies (first level). Second, our four studies found that seven second- and third-level taxa showed only negative, four only positive, and four mixed positive and negative responses. Third, regarding taxonomic resolution, no third-level taxon reacted differently to mowing compared to the second-level taxon it belongs to. Our results indicate that for some taxa, mowing has a consistent negative (e.g. Diptera) or positive effects (e.g. Coleoptera). We suggest those groups have uniform phenological traits that make them especially vulnerable to mowing. For taxa showing mixed responses, we expect that study-dependent factors such as region, sampling method, and grassland management affect their response to mowing.