Arthropod biodiversity in apple orchards: the influence of hedgerows and landscape heterogeneity on community structure and ecosystem services in Medea (Algeria)

This study investigates the role of hedgerows and landscape heterogeneity in supporting arthropod biodiversity within apple orchards in the Médéa region of Algeria. Comparing two contrasting orchard systems—one extensive with structural elements (Si El Mahdjoub) and one intensive without (Benchicao)—arthropod communities were sampled over a full annual cycle using pitfall traps, colored sticky traps, and sweep netting. A total of 251 arthropod taxa were recorded across both sites. Si El Mahdjoub exhibited significantly higher species richness (229 species vs. 184) and total abundance (4,351 vs. 3,183 individuals) compared to Benchicao. Despite similar overall species counts, Si El Mahdjoub showed greater taxonomic diversity with more even species distribution and higher effective diversity (Shannon H’ and Simpson indices). The site with hedgerows supported a more functionally diverse arthropod assemblage, with higher numbers of predators (786 vs. 434) and parasites (530 vs. 482), while Benchicao was dominated by phytophagous species. Plant-arthropod richness correlation was strongly positive at Si El Mahdjoub (r = 0.97, p = 0.026) but negative at Benchicao (r = -0.66, p = 0.54). Seasonal analysis revealed that summer harbored the highest number of unique taxa (22.3%), with spring-summer overlap being most significant (32.3% shared taxa). Ordination analysis showed seasonality as the primary driver of community structure, with winter-autumn communities clustering separately from spring-summer assemblages. These findings underscore the ecological value of hedgerows and structural complexity in agricultural landscapes. Hedgerows enhance both taxonomic and functional arthropod diversity, contributing to ecosystem services such as biological pest control. The results support the resource heterogeneity hypothesis and highlight the importance of agroecological infrastructures for sustainable biodiversity management in orchard systems.