Impacts of land use on bird communities in the Western Himalaya: Insights from a two-decade-long monitoring program.

Anthropogenic land use change due to farming and livestock grazing has altered biodiversity composition greatly in ecosystems around the world. This is especially true in grasslands and rangelands; however, these ecosystems in high-altitude regions remain understudied. Moreover, anthropogenic effects in these habitats in the long term remain poorly understood. We studied bird densities and composition across four different habitats along a gradient of intensity of land use (crop fields, grazed meadows, grazed steppe, and ungrazed steppe), in the Trans-Himalayan region of Spiti Valley in Himachal Pradesh, India. Started in 2002, this continuing study is one of the longest running bird monitoring programs in India. We found that bird community composition differed significantly along the land use intensity gradient. Although crop fields had the highest bird densities, the bird community here was homogenized, comprising mainly habitat generalist species. Ungrazed steppe harbored more habitat specialist species and high bird densities. Grazed habitats were generally unfavorable for birds, with lower densities and possibly lower species richness. Decadal changes in densities revealed declines in the least used ungrazed steppe habitat, highlighting a possible role of climate change. Our study underscores the importance of land use type in affecting avifauna in the Trans-Himalaya. Holistic land management practices, including continuing traditional (organic) farming and maintaining ungrazed patches in grazed rangelands, could help maintain coexistence between biodiversity and people in these multiuse landscapes.