Impact of native forest restoration on endemic crickets and katydids density in Rodrigues island
Native species of oceanic islands are often unique and of conservation concern. Native habitat restoration schemes are now conducted on many oceanic islands, and are often characterized by both the small sizes of the restored areas, and the high degradation level prior to restoration. Whereas arthropods are often neglected in restoration schemes, on small tropical islands they may represent the largest proportion of extant native terrestrial animals surviving habitat degradation. The island of Rodrigues, in the South Western Indian Ocean, is typical of such cases. The only patches of forest and bushes remaining on Rodrigues in 1996 were dominated by non-native invasive species. Since 1996, restoration schemes were conducted in Grande Montagne Nature Reserve. Benefits of these 15 years of native forest restoration were assessed on endemic Orthoptera density and diversity using acoustic monitoring and insect density measurements. Unrestored exotic plant-dominated areas were a low-density reservoir for endemic Orthoptera, many of which were new to science. Habitat restoration increased by four to seven times the density of these endemic Orthoptera, depending on the restoration scheme. The presence of managed areas did not significantly increase the density of endemic Orthoptera on the neighboring unrestored exotic plant-dominated areas.
KeywordsOrthoptera Endemism Acoustic monitoring Inventory and monitoring Mascarene
We acknowledge the National Parks and Conservation Service, Rodrigues Regional Assembly and Forestry Service, and the MWF for having allowed and helped our investigations. We thank Richard Payendee, Arnaud Meunier and all the MWF-Rodrigues team for their enthusiastic assistance. We thank Vincent Florens, Owen Griffiths, Julian Hume, Jean-Luc Rodeau, Wendy Strahm, Vikash Tataya, Andrea Waterstone, for their help and our discussions. This work was partially funded by the BIOTAS project, ANR-06-BDIV-002.
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