Abstract

WEN, L et al. Variation of botanical composition, forage production and nutrient values along a grassland degradation gradient in the alpine region of Qinghai-Tibet Plateau. Phyton (B. Aires) [online]. 2013, vol.82, n.1, pp.45-54. ISSN 1851-5657.

The alpine grassland in the Qinghai-Tibet Plateau is an extensive rangeland ecosystem sustaining a sparse population of traditional nomadic pastoralists in China. However, global climate change and anthropologic disturbances have severely degraded the alpine grasslands, and the consequences of this degradation are largely unknown. Forage is the only food source for livestock in the alpine region, and livestock is the major income source for nomadic herders. Therefore, it is critical to assess the forage quantity and quality along the current grassland degradation gradient. In this study, we examined the botanical composition, biomass of different functional groups, and forage grass nutritive values, and classified forage grasses according to their biological condition: lightly degraded, moderately degraded, heavily degraded and severely degraded grasslands. A sharp reduction in vegetative production and variations in botanical composition, plant coverage and nutritive values were associated with increasing degrees of degradation of the alpine grassland. Changes in botanical composition resulted in lower nutritive values in more than in less degraded alpine forage grasses. Given the productive importance of the alpine grassland, urgent action is extremely essential to protect it from degradation.

Keywords : Aboveground biomass; Alpine grassland; Degradation gradient; Forage nutrient; Qinghai-Tibet Plateau; Vegetation composition.

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