Habitat is more important than management for fruit-feeding butterfly assemblages in family-farm agricultural systems

Abstract

Abstract Agricultural expansion is a primary cause of biodiversity decline, as it leads to habitat loss and fragmentation. In contrast, small organic systems or agroforestry are considered sustainable means of production. However, the impact of management class (conventional or organic) and habitat (orchard or legal reserve) at the local scale, such as on small family farms, remains understudied. Butterflies exploit vegetation patches for supplementary and complementary resources and are sensitive to habitat change. Therefore, soil management and the quality of available habitat can be limiting for certain species, altering richness and composition in agricultural systems. We compared the alpha and beta taxonomic diversity of fruit-feeding butterflies between organic and conventional farms and between orchards and legal reserves to identify how management class and habitat type influence community structure. We sampled orchards and legal reserves on eight organic and eight conventional farms, obtaining 1,736 individuals belonging to 40 butterfly species. No differences were found between management classes; however, legal reserves had greater richness and abundance than did orchards. Composition differed primarily between habitats, with a small effect of management class. High global beta diversity values were obtained due to species exchange between habitats. The results indicate that orchard and legal reserve habitats harbor distinct assemblages, making the maintenance of legal reserves important for increasing the regional species pool. Implications for insect conservation Preserving forest fragments on agricultural properties ensures the maintenance of forest assemblages distinct from orchards. The availability of niches in legal reserves also allows for greater species richness and abundance.