Bird community structure in a mixed forest-production landscape in the northern Western Ghats, India

ABSTRACT

Production landscapes outside protected areas are important for the conservation of wildlife, especially in countries like India with high biodiversity and human densities. Production landscapes like plantations often occur in close proximity to biodiversity-rich areas. Rubber and cashew are lucrative plantation crops in India, which although grown under similar environmental conditions, vary in their management and productivity. These plantation crops are often found along the edges of forests, thereby creating a buffer between forested and urban landscapes. While these areas have the potential to be a refuge for species otherwise restricted to natural forests, they are poorly-studied. To address this knowledge gap, we studied how habitat type (cashew, rubber or forest) and habitat characteristics affect bird diversity and guild structure in the Tillari landscape of Western Ghats, Maharashtra. Additionally, we examined how these effects are mediated by distance of plantations to nearest forest edge. In each habitat type, in 2018, we sampled birds six times each in 30 locations using fixed radius point counts. We found that bird diversity in cashew plantations (14 species) was comparable to that of adjoining forests (15 species). Rubber plantations, on the other hand, had lower bird diversity (9 species) than that in cashew or forests. When bird diversity was analysed based on dietary guilds, rubber plantations had fewer bird species in all guilds and cashew plantations had higher abundance of nectivores and lower richness of insectivores than in forest. Distance from the forest did not affect bird diversity in rubber plantations, whereas cashew plantations had fewer nectivorous birds and higher insectivorous birds away from the forest edge. Our results show that cashew plantations can serve as an important surrogate habitat for forest birds in the northern Western Ghats. The findings indicate the unsuitability of rubber plantations for sustaining bird diversity. While there are many studies available on bird diversity in rubber plantations, this is among the first studies of bird community structure in cashew plantations. At a time when forests are rapidly being cleared for plantations, our findings provide valuable data to examine the differential impacts of plantation type on biodiversity.