Tillage agriculture and afforestation threaten tropical savanna plant communities across a broad rainfall gradient in India

The consequences of land-use change for savanna biodiversity remain undocumented in most regions of tropical Asia. One such region is western Maharashtra, India, where old-growth savannas occupy a broad rainfall gradient and are increasingly rare due to agricultural conversion and afforestation.
To understand the consequences of land-use change, we sampled herbaceous plant communities of old-growth savannas and three alternative land-use types: tree plantations, tillage agriculture, and agricultural fallows (n=15 sites per type). Study sites spanned 457 to 1954 mm of mean annual precipitation—corresponding to the typical rainfall range of mesic savannas globally.
Across the rainfall gradient, we found consistent declines in old-growth savanna plant communities due to land-use change. Local-scale native species richness dropped from a mean of 12 species/m2 in old-growth savannas to 8, 6, and 3 species/m2 in tree plantations, fallows, and tillage agriculture, respectively. Cover of native...