Oral presentation- Open Session 12th International Mammalogical Congress

Migratory livestock grazing significantly impacts rangeland vegetation and wild-ungulate population in the Indian Trans-Himalaya (#426)

Abhishek Ghoshal 1 2 3 , Yash Veer Bhatnagar 2 3 , Bivash Pandav 1 , Charudutt Mishra 2 3 , Kulbhushansingh R Suryawanshi 2 3
  1. Wildlife Institute of India, Dehradun, Uttarakhand, India
  2. Science and Conservation, Snow Leopard Trust, Seattle, Washington, United States of America
  3. High Altitude Program, Nature Conservation Foundation, Mysore, Karnataka, India

Intense livestock grazing outcompetes wild ungulates in low-productivity rangelands. This is a long-standing and highly debated conservation problem globally. We examined impacts of migratory livestock grazing on Trans-Himalayan rangeland and Asiatic ibex, a wild ungulate and primary prey of the endangered snow leopard. Vegetation and ibex were sampled in an intensely grazed (livestock density 63 sheep-goat km-2) and ungrazed areas, during spring (before grazing), summer (during grazing) and autumn (after grazing). Proportionate to vegetated area, independent randomly laid 1m x 1m plots were sampled for vegetation cover and biomass estimation (Cover: NUngrazed=237; NGrazed=127; Biomass: NUngrazed=119; NGrazed=64). Ibex density and young:adult-female ratios were estimated by repeatedly sampling 17 trails using double-observer methods across both treatments for the three time periods and two consecutive years. Graminoid and herb biomass were significantly higher in ungrazed than grazed areas (ANOVA; Graminoid: FTreatment=16.05; P=<0.001; Herb: FTreatment=22.75; P=< 0.001). Overall vegetation composition was dissimilar across ungrazed and grazed areas (Morisita Index 0.18); however, palatable species composition was similar (Morisita Index 0.70). Biomass of palatable species was 2.25 times higher in ungrazed areas. Total off-take of dry forage by migratory livestock from grazed pastures (61 km2) was 10,658 kg km-2 over two months of grazing. Ibex density was 1.80-7.0 times higher in ungrazed areas in 2015, while 2.45-4.7 times higher in ungrazed areas during 2016. Ibex yearling:adult-female ratio was six times higher in ungrazed areas. Significant reduction in forage availability lowered ibex density and yearling:adult-female ratios in grazed areas, suggesting migratory livestock outcompetes ibex through exploitative competition.