Spatial and temporal effects of land use change as potential drivers of odonate community composition but not species richness

Land-use changes and land cover change are drivers of diversity. The effects of such drivers over the temporal trend in species richness and composition, particularly on invertebrate diversity in megadiverse countries, is controversial. One key animal group to clarify this controversy is that of odonate insects (dragonflies and damselflies), given their combined close water-land requirements. We have investigated whether changes in land use impact species richness and composition of odonates from 1980 to 1993 (period I) to 1994-2010 (period II) in Mexico. The effect of land use changes and land cover changes on species richness was analyzed using multiple diversity measures and at different spatial scales. In period II, an area reduction in original vegetation and increase in land use occurred. Responses to land use varied among spatial scales and measures of diversity but, overall, species richness in the transformed area was higher than in the original vegetation. However, species composition indicated a high species turnover inside hydrologic regions (watersheds) and across land uses classes, particularly between original and secondary vegetation. Our interpretation is that despite high land use conversion in Mexico, adult odonates seem resilient to land use change in terms of species richness, but not in species composition, which is in partial agreement with the intermediate disturbance hypothesis. Finally, we suggest that hydrologic region scale and use of entropy maximization (HCDT entropy), could provide a reliable biodiversity estimation of species loss associated with land use change.