How mountain ungulates of the trans-Himalaya live together
The causes and mechanisms that determine herbivore species richness in grazing ecosystems are poorly understood. This study has been designed to determine the role of competition, habitat heterogeneity and biogeography in determining large herbivore species-richness patterns at a regional scale.
Role of ungulates in the high-altitude ecosystem
Large herbivores play a unique role in ecosystem functioning, and are economically important around the world. However wild herbivore diversity is declining and such rapid loss of diversity from grazing systems has stimulated research to evaluate how changing herbivore diversity influences functional properties of ecosystems. Nevertheless, the causes and mechanisms that determine herbivore species richness in grazing ecosystems are poorly understood. This project has been designed to determine the role of competition, habitat heterogeneity and biogeography in determining large herbivore species-richness patterns at a regional scale.
The Trans-Himalayan rangelands represent a dry-alpine-steppe ecosystem characterised by very low primary productivity and a short growth season in summer. Through aeons, a large-herbivore assemblage has evolved to exploit this otherwise hostile and marginal environment. However, human endeavours today threaten the integrity of this unique ecosystem.
The Indian Trans-Himalaya is located at the junction of three bio-geographic realms viz., Palaearctic, Ethiopian and Oriental, and contains biological elements of all these realms. Our work in the region over the last eight years has generated information on the ecology of wild and domestic herbivores. The proposed work is aimed at building upon that information, as well as addressing new ecological issues that challenge ecologists and conservationists.
Although large herbivore diversity on a continental or global scale may be ultimately determined by climatic factors, at local and regional scales, biotic interactions such as facilitation and competition become more important. Facilitation may enhance species richness in the high productive areas in the tropics, but it is perhaps less important in structuring herbivore assemblages in ecosystems with lower productivity, and competition is rather likely to play a more important role. This has been demonstrated by our recent work in the Indian Trans-Himalaya. Nevertheless, how competitive effect interacts with other potential determinants of herbivore species richness is less understood.
In this project, we are investigating the relative importance of competition, habitat heterogeneity, and biogeography in structuring the Trans-Himalayan large herbivore assemblages, and the spatial variation in species-richness at a regional scale.
Our study is expected to make contributions to the current understanding of large herbivore community ecology, and will assist in better conservation management of the magnificent mountain ungulates of the Trans-Himalaya.
- Book Chapter2016Richness and size distribution of large herbivores in the HimalayaIn: Asian large herbivore ecology, Ahrestani, F., Sankaran, M. (eds.), Springer.Download
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Species diversity across several taxa ranging from plants to vertebrates is reported to decrease with altitude, or to show a mid-elevation peak in mountain systems. Plant biomass availability for herbivores is similarly expected to decline with altitude as temperature becomes limiting. However, the relationship between herbivore species richness and altitude has not been examined in detail. We show that while the overall regional pattern (gamma-richness) for 25 large-herbivore species (56 % grazers, 44 % browsers/mixed feeders) in the Western Himalayas shows a mid-elevation peak, the species richness of grazers increases nearly monotonically with altitude peaking at 4000–5000 m. Median body mass of herbivores decreased with altitude, suggesting greater suitability of higher elevations for smaller bodied herbivores. We propose that seasonal altitudinal migration patterns, biogeographic influences, increases in the abundance of graminoids, and an increase in plant nutrients with altitude might explain the unusual high grazer species richness at higher altitudes in the Himalayan Mountains.
- Journal Article2014A penny saved is a penny earned: lean season foraging strategy of an alpine ungulateAnimal Behaviour 92, 93-100
- Journal Article2012Standardizing the double-observer survey method for estimating mountain ungulate prey of the endangered snow leopardOecologia DOI: 10.1007/s00442-011-2237-0
- Journal Article2010Multi-spatial co-distribution of the endangered Ladakh urial and blue sheep in the arid Trans-Himalayan mountains.Journal of Arid Environments, 74 : 1162–1169.
- Book Chapter2010Multiple Use of Trans-Himalayan Rangelands: Reconciling Human Livelihoods withWildlife Conservation.Wild Rangelands: Conserving Wildlife While Maintaining Livestock in Semi-Arid Ecosystem (eds J. T. Toit, R. Kock & J. C. Deutsch), pp. 291-311. Blackwell Publishing.
- Journal Article2008Distributional correlates of the Tibetan gazelle Procapra picticaudata in Ladakh, northern India: towards a recovery programme.Oryx, 42, 107-112.
- Journal Article2007A Strategy for Conservation of Tibetan Gazelle Procapra picticaudata in Ladakh.Conservation and Society, 5, 262-276.
- Journal Article2006Perceived conflicts between pastoralism and conservation of the Kiang Equus kiang in the Ladakh Trans- HimalayaEnvironmental Management, 38, 934-941
- Journal Article2004Competition between domestic livestock and wild bharal Pseudois nayaur in the Indian Trans-Himalaya.Journal of Applied Ecology, 41, 344-354.
- Journal Article2003Diversity, risk mediation, and change in a Trans-Himalayan agropastoral system.Human Ecology, 31, 595-609.