High mobility reduces beta-diversity among orthopteran communities – implications for conservation


Lorenzo Marini, University of Padova, Department of Environmental Agronomy and Crop Production, Viale dell’Università 16, 35020 Legnaro, Padova, Italy. E-mail: lorenzo.marini@unipd.it


Abstract.  1. The analysis of β-diversity, i.e. species turnover, across space is central to a wide array of ecological and evolutionary topics, also providing critical information to conservation planning. Although dispersal limitation has been demonstrated to play an important role in determining insect community structure, very little research has been done to test whether mobility might affect the diversity distribution of species across multiple spatial scales.

2. We considered orthopterans (Ensifera and Caelifera) inhabiting hay meadows to test whether species mobility modifies β-diversity patterns across three nested spatial scales (1-m2 plots within meadow, 1000-m2 meadows within landscape, and 19.6-km2 landscapes within a region) and along a gradient of management intensity.

3. Orthopteran community composition varied most significantly over broader spatial scales. Larger proportion of regional γ-diversity was mainly composed of β-diversity at the landscape scale, whereas this proportion was smaller at the plot and meadow scale.

4. Mobility, but not management, strongly modified β-diversity patterns. Sedentary species contributed to a greater proportion of β-diversity across all the investigated scales compared with mobile species.

5. Measures currently included in most agri-environment schemes have only focused on the extensive management at the field scale. Our results imply that orthopteran diversity would benefit from maintaining extensively managed meadows scattered throughout the whole region, as the loss of species-rich isolated grassland patches due to abandonment or eutrophication might cause severe reductions of the regional species pool. Increasing connectivity might be also considered as a complementary measure to increase species occupancy and population persistence, particularly for sedentary species.