Can extensively managed perennial crops serve as surrogate habitat for orthopterans typical of dry calcareous grasslands?

Abstract

Both agricultural intensification and abandonment are considered among the main drivers of biodiversity loss, especially for species typical of semi-natural grasslands. In the Mediterranean regions, semi-natural grasslands are often abandoned or replaced by perennial crops such as vineyards and olive groves with potential negative consequences on the associated diversity. However, when these crops are managed under low-intensity practices, their inter-row grass cover can potentially provide suitable habitats for grassland specialists. Here, we analysed the effects of land use on orthopterans by sampling 67 sites belonging to four different habitats (vineyards, olive groves, semi-natural grasslands and abandoned semi-natural grasslands) along a landscape composition gradient. Overall, species richness was highest in abandoned grasslands, while vineyards presented the lowest diversity. Semi-natural grasslands and olive orchards presented intermediate and similar species richness. However, this effect was significant only for Ensifera species, while species richness of Caelifera did not differ between the four habitats. Increasing forest cover within a scale radius of 500 m also increased Ensifera species richness probably providing undisturbed refugia at the margins. Orthopteran abundance was higher in semi-natural grasslands than in abandoned grasslands and vineyards. Despite the differences in species richness, we observed large overlap in species composition between olive groves and semi-natural grasslands suggesting that perennial crops managed under traditional, non-intensive practices can provide suitable habitats for orthopterans typical of semi-natural grasslands. In particular, olive groves appeared to be a better surrogate habitat than vineyards for the conservation of both Ensifera and Caelifera.