Ground beetles of two cultivated orchards and one mixed forest near Mostaganem, Algeria (Coleoptera Carabidae)

The aim of this study is to investigate the environmental factors affecting the seasonal changes in carabid assemblages (Coleoptera Carabidae) inhabiting a vineyard field, a pomegranate orchard, and a mixed forest near Mostaganem (NW Algeria). The study area included agricultural and forested plots in the wilaya (province) of Mostaganem along the Mediterranean coast. Two plots were cultivated, a vineyard and a pomegranate orchard, while the third site was a mixed forest. Pitfall trapping was used to collect beetles between April 2019 and March 2020. Traps filled with propylene glycol were checked every 15 days during the year. A principal component analysis was used to reduce the components of the observed variation of species and specimens during the seasons. To achieve this aim, we used the PAST app. Each site showed peculiar temporal species succession, dominance, and species diversity (number of specimens and species); species in common to the three sites were few. The pomegranate orchard showed the highest diversity (29 species, 984 specimens). The vineyard harbored 16 species and 546 specimens, and the diversity peaked during autumn and early winter when grapes were harvested. The mixed forest was relatively poor in terms of species and specimens. Five species of Graphipterus were present here. The diversity of the faunistic assemblages varied notably among seasons of the same site and the sites; it was also quite distinct from that previously described for other cultures nearby. We could not fully assess the role of environmental factors in the carabid assemblages’ dynamics and structure. Site management (culture, irrigation) likely affected the generalist carabids that dominated the cultures. Despite being relatively close and sharing similar environmental factors, sites harbored distinct species composition. We hypothesize that the hazardous dispersal of beetles also darkens the occurrence of patterns that model the composition of the assemblages.