Terrestrial arthropods diversity in the Argan Biosphere Reserve: Seasonal dynamics and ecological function roles

Abstract

Diversity, spatial patterns and temporal trends of terrestrial arthropod communities in the Arganeraie Biosphere Reserve of Morocco are poorly understood. Arthropods were seasonally sampled using pitfall traps at four sites, three of which are Argan forest ecosystem and one of which is a modern Argan grove. Diversity parameters were seasonally measured. Observation allowed identification of 161 morphospecies belonging to the five classes Chilopoda, Malacostraca, Collembola, Insecta and Arachnida were recorded. Captures were dominated by insects, representing more than 90% of the total trapped individuals. Insecta were the most diversified class (122 morphospecies), followed by Arachnida (33). The three other classes were less diversified with two species each. Among insects, Coleoptera and Hymenoptera were the most diversified groups. Diversity parameters exhibited seasonal variations. The highest arthropod abundance per sample was recorded during spring, while observed richness was higher in spring and summer. Shannon diversity index showed no significant difference among seasons. The composition of terrestrial arthropod communities between sites changed among seasons. A high dissimilarity was reported between the terrestrial arthropod community of Belfaa and those of other sites. The classification of arthropods into trophic guilds shows the importance of both predators and detritivores, which shows a higher abundance in spring and summer. Overall, predators guild richness was higher than others among seasons. This study highlights spatiotemporal diversity composition and structure of terrestrial arthropods community associated with the Argan ecosystem, complementing the unique diversity and proliferation of ecotypes present in Morocco.