How can an intensively used agricultural landscape preserve diversity of Orthoptera assemblages?

Abstract

Protecting biodiversity of agricultural lowlands is one of the main topics of European nature conservation. Understanding the relationship and interaction between cultivated and other habitat types is necessary since arable lands cover a significant part of the landscape, but former studies rather focus on the remaining semi-natural sites. Orthoptera assemblages, which are sensitive indicators of habitat structure and conservation value, were studied in a traditional intensively used agricultural area (it has been cultivated for several decades or even 250 years) to assess how arable land and ruderal linear habitats together can preserve insect diversity. Twenty-nine Orthoptera species, including protected Gampsocleis glabra, Acrida ungarica and Celes variabilis were recorded. We identified four assemblages and their character species reflecting intensity of land use. Assemblages of agricultural sites differed from the assemblages of semi-natural habitats used as control group. Revealing their quantitative composition, ratios of lifeforms and ecotypes, character species, and use of Grasshopper Conservation Indexes (GCI) helped to identify habitat types that can effectively preserve natural insect diversity, even under long-term intensive land use regime. Implications for conservation Considering our findings, the role of linear ruderal habitats and less intensively cultivated arable lands covered by alfalfa and red clover in maintaining of biodiversity is higher than it was formerly assumed. Increasing ratio of these less intensive cultures (at least to 5%, optimally 8–10%) and its connection with each other and linear ruderal habitats may provide temporary habitats and corridors for metapopulations living in mosaic landscape. The local greening programs can help Orthoptera conservation as well through supporting the production of these cultures. Complex landscape- and crop rotation planning, that regard the spatial and temporal distribution, and ratio of agriculture landscape elements may become an effective tool for biodiversity conservation and forming sustainable farming systems.