Effects of land use patterns on the diversity and conservation status of butterflies in Kisii highlands, Kenya

Abstract

Habitat degradation poses a great threat to biodiversity conservation. Abundance and diversity of butterflies is an indicator of good environmental health. Understanding how different butterfly species respond to habitat degradation is a necessary step towards the development of effective measures to enhance environmental protection. This study investigated the impact of land use patterns on the diversity, abundance, and conservation status of butterflies in the Kisii highlands; a densely-populated region in Kenya that has received little attention in ecological studies. Sampling was done through a line transect of 300 m. A total of 2799 individual butterflies comprising 67 species were recorded across seven land cover types; secondary forest, grasslands, riverine, human settlement, mixed farmlands, monoculture, and mining areas. The secondary forest, riverine and mixed farmlands recorded more butterflies (37.0, 26.0, and 15.5 %, respectively), followed by grasslands (12.5 %), while monoculture, human settlements, and mines had the least number of butterflies (3.0 % each). Moreover, the secondary forest, riverine and mixed farmland land cover types were the most species rich. Nymphalidae were the most abundant (38 species) whereas, Papilionidae the least (3 species) in the region. Junonia sophia was the dominant species. Butterflies were most diverse in the secondary forest (Shannon–Weaver diversity index, H′ = 2.89), while the human settlement had the least (H′ = 1.25). One-way ANOVA analysis indicated a higher species similarity between secondary forest, mixed farming and riverine land cover types compared to a low species similarity between secondary forest and mining, grassland, monoculture and human settlement. Butterfly abundance and distribution was different between the dry and wet season among the land cover types. Therefore, land use patterns had effects on butterfly abundance and diversity and their conservation is threatened if proper management practices are not put in place. Planning of land use activities should thus encourage agro-forests/secondary forests interspaced with other land use activities to enhance environmental health and improve on biodiversity conservation.