Macroinvertebrate richness patterns in North African streams [Ressource électronique]

To test the hypothesis that macroscale environmental variables explain local taxonomic richness of stream macroinvertebrates, and then to identify the relationships between these variables and benthic fauna richness in North Africa. North Africa, from West Morocco to East Tunisia. Using a large-scale data base made of 211 sampling sites gathered from an area of 500,000 km², an artificial neural network model has been built to identify and predict the influence of macroscale environmental variables on local macroinvertebrate richness. The correlation coefficient ( r) between observed and estimated taxon richness values was 0.75 ( P < 0.001), and the model explained more than 55% ( r² = 0.563) of the macroinvertebrate richness variation. Macroinvertebrate richness was, therefore, accurately predicted using only three environmental variables accounting for hydrology (number of rainy days), geographical factors, i.e. connections between European and North African land masses (longitude) and climatic gradient (altitude). Stream macroinvertebrate richness in North Africa results from a combination of climatic, geographical and hydrological parameters. Although consistent with current biogeographic and ecological concepts mainly derived from European and North American streams, this study underlines the specificity of dry Mediterranean ecosystems. The shape of diversity patterns results from climatic conditions and their associated environmental seasonal dynamics, which screens geographical processes. [ABSTRACT FROM AUTHOR] Copyright of Journal of Biogeography is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)