Influence of some abiotic parameters on the biodiversity of macroarthropods in the "lep-liye" forest stream

Abstract

A study was carried in the locality of Ngog-mapubi. The objectif was to evaluate the spatio- temporal dynamics of macro-arthropods in relation to seasonal and physico-chemical quality of forest stream. Benthic macro-arthropods were sampled during the short dry season (SDS) and the long rainy season (LRS). Physico-chemical parameters such as temperature, oxygen and carbon dioxide fixation, oxydability of oxygen, carbon dioxide, suspended solids, nitrate, pH were measured and analyzed follow standard methods. A sampling net was used to collect macro-arthropods at (Lep1) up-stream, (Lep 2 and Lep3) med-stream and (Lep 4) down-stream. 313 macro-arthropods predominated by Hexapoda (89%) and Malacostraca (11%) were collected and mainly identified as: Odonata (43.13%), Hemiptera (15.34%), Coleoptera (13.74%), followed by Décapoda (11%), Trichoptera (8.3%), then Ephemeroptera (7.33%) and Diptera (0.98%). Concerning biocenotic analysis, the diversity and abundance index were higher during the LRS, Shannon index showed significant difference between the two seasons, while from a spatial point of view, the Mann-Whitney U-test revealed a significant difference between the coarse substrate stations compared to those with fine substrate stations.