Butterfly (Lepidoptera) assemblage composition and distribution patterns in King Sabata Dalindyebo Municipality, Eastern Cape, South Africa

摘要

Butterflies (Lepidoptera) have attracted more attention as bio-indicators of terrestrial ecosystems than other terrestrial arthropods. This study determined butterfly species turnover at a priori selected habitat patches inside Nduli Nature Reserve and its surrounding landscape, and their response to measured environmental variables. Using the line transect method, 516 butterfly individuals belonging to 22 species were sampled from all 16 sampling units (Sus), of which 13 species occurred in two or more Sus across the study site. Habitat patches outside the reserve were higher in butterfly species richness and abundance than inside the reserve. Papilio demodocus Esper, Borbo gemella Mabille, Precis octavia (Cramer) and Hypolimnas missipus (Linnaeus)were each restricted to one sampling unit. Hierarchical clustering using Bray-Curtis similarity matrices and correspondence analyses grouped sampling units according to butterfly species sampled. Canonical correspondence analysis results indicated thatcertain site (environmental) variables, e.g. percentage herb cover, grazing intensity, distance to the city centre and average flower density accounted for species distribution patterns across Sus. The implications of the study suggest that habitat patchlevel management for conservation action should aim at preserving sufficient herb cover and nectaring plants, especially during the summer season to cater for all developmental stages of butterfly species in the study area. Furthermore, species richnesswithin the reserve can be encouraged by using vegetation linkages and corridors between the reserve and its surrounding landscape. Butterflies identified during the study can serve as indicator species for assessing the conservation value of habitat patches in the study area and for increasing public awareness of the need to conserve butterflies and the invertebrate fauna of the King Sabata Dalindyebo Municipality between the months of November and April.