Vegetation-environment relationships in a South Asian tropical montane grassland ecosystem: restoration implications

We studied the role of environmental factors driving species distributions, community structure, and ecosystem properties in an endangered montane grassland ecosystem in the Nilgiris, Western Ghats. We examined plant composition, ecosystem properties and environmental factors in one of the largest grassland sites in the Nilgiris. Ordination analysis showed that environmental gradients, mainly slope and aspect, controlled the distribution of the dominant plants. Some of the abundant species showed mutually exclusive distributional patterns along gradients, and some species exhibited distinct association with other species suggesting similar environmental tolerances. Classification analysis identified four community types, but ordination revealed that these communities formed a continuum along environmental gradients. Slope and soil depth strongly influenced aboveground biomass while species composition was influenced by the aspect. This study provides baseline data on grassland communities in the Nilgiris, and the results suggest that restoration activities should factor in environmental preferences of the plants as well as natural species associations. Resumen: Estudamos o papel dos fatores ambientais influenciando a distribuicao das especies, a estrutura da comunidade, e as propriedades do ecossistema num ecossistema de pastagens montanhosas ameacadas de extincao no Nilgiris, Gates Ocidentais. Examinamos a composicao de plantas, as propriedades do ecossistema e os fatores ambientais numa das maiores estacoes de pastagem em Nilgiris. A analise de ordenacao mostrou que os gradientes ambientais, principalmente declive e o aspecto, controlavam a distribuicao das plantas dominantes. Algumas das especies abundantes apresentaram padroes de distribuicao mutuamente exclusivos ao longo dos gradientes, e algumas especies exibiram uma associacao distinta com outras especies, sugerindo tolerâncias ambientais similares. Analise de classificacao identificou quatro tipos de comunidades, se bem que a ordenacao revelou que essas comunidades formavam um continuum ao longo dos gradientes ambientais. O declive e a profundidade do solo influenciaram fortemente a biomassa aerea, enquanto que a composicao de especies foi influenciada pelo aspecto. Este estudo fornece dados de base sobre as comunidades de pastagem em Nilgiris, e os resultados sugerem que as atividades de recuperacao deve levar em consideracao as preferencias ambientais das plantas, bem como as associacoes naturais das especies.