TROPICAL FORESTS AND THE SPECIFIC DIVERSITY OF ISOPTERA IN FRENCH GUIANA
عنوان دوره: دومین کنگره بین المللی حشره شناسی ایران
نویسندگان
چکیده
French Guiana is an overseas French department, located on South America. About 98% of French Guiana is forested and there is a high level of biodiversity in terms of both flora and fauna in this region. The flora of Guyana is now estimated at 7000 native species, including 5700 species of vascular plants and more than 1200 trees. From 2002 to 2016, I have studied different ecological environments of French Guiana, for example: tropical rainforests, coastal mangroves, savannahs, inselbergs and many types of wetlands. All over, the termites of the mesofauna of the soil, on the trees are collected and have been systematically examined. In this study, I used the protocol described by Davies and Eggleton (1997, 2002, 2003). It consists of the realization of transecs (a transec = RTA: Rapid Termit Assesment) 100 m long and 2 m wide, divided into 20 quadrats of 5m x 2m. The Environmental variables (brightness, pH, litter depth, diameter at the height of the trees, height of vegetation, water content of litter or soil) have been measured and the multivariate analysis has been done. More than 160 species and 48 genus have been recorded from French Guiana. The results confirm that termites represent approximately a quarter of the known species of Isoptera of the area (French Guiana, Surinam, British Guiana, Amazonian Brazil and Venezuela). The Termitidae include the majority of genus and the species and dominate the other two families Kalotermitidae and Rhinotermitidae. Nasutitermes with 32 species is largely dominant in the family Termitidae. This study shows that the termites are sensitive to the environmental variables. Species diversity and the abundance of termites in the dense forests are two times more than in the secondary forests. They are 10 times more important than those of the open forests, savannas, inselbergs and anthropized zones (There are 85 species in dense forests with primary forest characteristics, 38 species in secondary forests, 10 species in open forest, 8 species in the savannas, 5 species in the inselbergs and 6 species in the urban areas). The reduction in plant diversity, the fragmentation of the forests and the use of their natural resources produce an imbalance which can lead to ecological perturbation, which are perceptible through the diversity of the termites. The diversity and specific abundance of termites are significant indicators for estimating the biodiversity in this part of the world.
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