THE TIMES THEy ARE A CHANGIN’: IMPACT OF LAND-uSE SHIFT AND CLIMATE WARMING ON THE ODONATE COMMuNITy OF A MEDITERRANEAN STREAM

– We assessed the observed effects of land-use alterations and global warming by analyzing changes in the Odonata community of a Mediterranean stream in northeastern Algeria, sampled at a 25-year interval. Results indicate that species richness has increased from 13 to 21 species. However, the apparent increase in species richness seemed to mirror recent physical and chemical changes brought upon the stream. In particular, these anthropogenic environmental changes seemed to have been driving a large-scale shift in the composition of the Odonata community of Wadi Bouaroug with an influx of widespread, thermophilic species ( Paragomphus genei, Crocothemis erythraea, Sympetrum fonscolombii, trithemis spp.) at the expense of rare, stenotypic species (Coenagrion puella, gomphus lucasii). In the light of impending and challenging climatic scenarios, we urge that steps should be taken to set up more long-term monitoring schemes and research of North African streams that may provide insights into causal mechanisms of global changes. FRESHWATER BIODIVERSITy CLIMATE CHANGE CO-INERTIA ANALySIS LAND-uSE CHANGE MEDITERRANEAN STREAMS MONITORING NORTH AFRICA ODONATA ASSEMBLAGES 26 F. MORGHAD, F. SAMRAOuI, L. TOuATI, B. SAMRAOuI Vie milieu, 2019, 69 (1) rity (Simaika & Samways 2009) and to provide reliable assessments of hydrology and habitat alterations of fluvial systems (Ferreras-Romero et al. 2009). In the face of mounting anthropogenic stressors ranging from habitat loss to recreational activities, dragonflies and freshwater biodiversity as a whole are increasingly threatened (Clausnitzer et al. 2012). Generally, individual species may respond differentially to changes (Pearson et al. 2014). Thus, in an ever changing landscape, it is crucial to reassess the conservation status of species (Rovelli et al. 2016). In addition, to mitigate the impacts of global and local alterations and develop sustainable management strategies, there is a need to assess and understand the consequences of ecosystem changes (Hooper et al. 2012). Bio-assessments provide such cost-effective and sensitive tools to monitor the consequences of human activities (Rovelli et al. 2016). Odonatological surveys of Wadi Bouaroug started in 1989 with a systematic study being carried out in 19931994 (Benchalel & Samraoui 2012). Recently, a parallel survey to our own study was carried out at the same locality (Benchalel et al. 2018). The main objectives of our study were to record the impact of environmental changes, principally land use changes and climate warming on the Odonate assemblage of a North African stream and to underscore the value of long-term ecological studies of Mediterranean streams by comparing past and present data. MaTeRIals aND MeThODs Study area: The study area is located in North-eastern Algeria (Numidia) (Fig. 1) which experiences a typically Mediterranean climate characterized by a hot, dry season (May to October) and a mild, wet season (November to April). The annual rainfall varies from 700 mm to 950 mm. A large part of the wadi crosses the Natural Reserve of Brabtia before reaching Lake Mellah, a brackish lagoon linked to the Mediterranean Sea by a