Online first articles

This study examines the factors influencing the composition of Odonata communities in Sierra Nevada, a distinctive biogeographic region in the southeastern Iberian Peninsula. Odonates are valuable indicators of freshwater health, facing threats from both climate change and human-induced habitat alterations. Effective conservation strategies rely on thorough ecological assessments analysing the relationship between species and their environment. Sierra Nevada's diverse habitats and climatic gradients provide a unique setting for this research. We conducted quarterly sampling of larvae over three years (2012-2014) at 216 stations covering lotic (rivers, streams) and lentic (ponds, pools) habitats. Physicochemical variables and habitat characteristics were recorded. Generalised Linear Latent Variable Models (GLLVM) were used to analyse species interactions and the influence of environmental variables on community composition. The research revealed a diverse odonate fauna of 29 species (34.5% Zygoptera; 65.5% Anisoptera). Species richness and community composition varied significantly with habitat and altitude, ranging from 1 to 11 species per location (mean = 3.18 ± 2.45). Some species were widespread, while others were found in specific habitat or altitudinal preferences. Abundance analysis highlighted two dominant species: Cordulegaster boltonii in lotic and Libellula depressa in lentic habitats. GLLVM analysis identified distinct clusters of odonate species and their key environmental drivers. In lotic habitats, distinct associations included a C. boltonii dominance zone in headwaters and a basic rheophilic association at lower altitudes. In lentic habitats, a basic lentic association characterised by Pyrrhosoma nymphula, L. depressa, Sympetrum meridionale and Sympetrum striolatum prevailed in high-altitude ponds. This study underscores the importance of considering the variability in larval ecology of damselflies and dragonflies for effective conservation planning. Our findings advance the understanding of odonate ecology in Mediterranean high-altitude ecosystems, providing crucial knowledge for developing informed conservation strategies amidst environmental change.