Changes in Arthropod Assemblages along a Wide Gradient of Disturbance in Gabon |
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| Authors: | YVES BASSET OLIVIER MISSA ALFONSO ALONSO SCOTT E. MILLER GIANFRANCO CURLETTI MARC DE MEYER CONNAL EARDLEY OWEN T. LEWIS MERVYN W. MANSELL VOJTECH NOVOTNY THOMAS WAGNER |
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| Affiliation: | 1. Smithsonian Tropical Research Institute, Apartado 0843‐03092, Balboa, Ancon, Panama City, Republic of Panama, email bassety@si.edu;2. Department of Biology, University of York, P.O. Box 373, York YO10 5YW, United Kingdom;3. Smithsonian Institution/Monitoring and Assessment of Biodiversity Program, 1100 Jefferson Drive S.W., Suite 3123, Washington, D.C. 20560‐0705, U.S.A.;4. Department of Systematic Biology, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560‐0105, U.S.A.;5. Museo Civico di Storia Naturale, Cas. Post. 89, 10022 Carmagnola TO, Italia;6. Royal Museum for Central Africa, Leuvensesteenweg 13, 3080 Tervuren, Belgium;7. Plant Protection Research Institute, Private Bag X134, 0121 Queenswood, Pretoria, South Africa;8. Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom;9. Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa;10. Biology Center of the Czech Academy of Sciences and School of Biological Sciences, University of South Bohemia, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic;11. Universit?t Koblenz‐Landau, Institut für Integrierte Naturwissenschaften–Biologie, Universit?tsstr. 1, 56070 Koblenz, Germany |
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| Abstract: | Abstract: Searching for indicator taxa representative of diverse assemblages, such as arthropods, is an important objective of many conservation studies. We evaluated the impacts of a wide gradient of disturbance in Gabon on a range of arthropod assemblages representing different feeding guilds. We examined 4 × 105 arthropod individuals from which 21 focal taxa were separated into 1534 morphospecies. Replication included the understory of 3 sites in each of 4 different stages of forest succession and land use (i.e., habitats) after logging (old and young forests, savanna, and gardens). We used 3 complementary sampling methods to survey sites throughout the year. Overall differences in arthropod abundance and diversity were greatest between forest and open habitats, and cleared forest invaded by savanna had the lowest abundance and diversity. The magnitude of faunal differences was much smaller between old and young forests. When considered at this local scale, anthropogenic modification of habitats did not result in a monotonous decline of diversity because many herbivore pests and their associated predators and parasitoids were abundant and diverse in gardens, where plant productivity was kept artificially high year‐round through watering and crop rotation. We used a variety of response variables to measure the strength of correlations across survey locations among focal taxa. These could be ranked as follows in terms of decreasing number of significant correlations: species turnover > abundance > observed species richness > estimated species richness > percentage of site‐specific species. The number of significant correlations was generally low and apparently unrelated to taxonomy or guild structure. Our results emphasize the value of reporting species turnover in conservation studies, as opposed to simply measuring species richness, and that the search for indicator taxa is elusive in the tropics. One promising alternative might be to consider “predictor sets” of a small number of taxa representative of different functional groups, as identified in our study. |
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| Keywords: | indicator taxa predictor sets rainforest species loss species turnover bosque lluviosos conjuntos pronosticadores pé rdida de especies renovació n de especies taxa indicadores |
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