Impacts of a changing climate and yak herding practices on apine rangelands and Tibetan livelihoods in Southwest China.

详细信息   

• 作者：Haynes ; Michelle A.
• 学历：Doctor
• 年：2011
• 导师：Waller, Donald M.,eadvisor
• 毕业院校：The University of Wisconsin
• ISBN：9781267062796
• CBH：3488663
• Country：USA
• 语种：English
• FileSize：6337474
• Pages：143

文摘

Montane regions of Southwest China support hotspots of cultural and biological diversity that are undergoing rapid cultural and ecological change. These regions also provide traditional summer pastures for yak herding and sources for medicinal plants. We used satellite imagery, government records, field surveys, dendrochronology, and interviews with yak herders and officials to examine changes in climate and land cover and to test relationships among these factors in northwest Yunnan. Climates have changed dramatically with pronounced increases in temperatures and declines in spring snow cover. Although substantial changes in policies and livelihoods have also occurred over recent decades, these did not strongly affect alpine grasslands until about 1990. Since then, woody shrub encroachment has eliminated 39% of the alpine meadows in the region. Rates of encroachment vary from <；5--65% and vary inversely with spring snow cover and positively with existing woody cover. Despite declines in areas suitable for grazing, herd sizes have quadrupled over the last 50 years, intensifying impacts on palatable plants. Surveys of plant species cover and richness along a gradient of declining grazing intensity reveal conspicuous increases in species richness, plant height, and shrubs while grass cover tends to decline. This grazing gradient parallels grass cover and bare ground. These results suggest that grazing is greatly affecting these alpine grasslands. We interviewed households in Deqin County on their traditional knowledge and the changes they have observed in climatic and ecological conditions, livestock health, and land management. Herders reported that shrub invasions of alpine meadows have reduced livestock forage, the productivity of alpine rangelands, and yak health. They also reported warming temperatures. Butter production has declined by 30% over the last two decades. Herders are shifting to diversify sources of income when possible, but villagers in remote and protected areas continue to depend on livestock for much of their livelihood. Changes in climate, policies, and economic incentives have interacted to increase grazing pressure on shrinking alpine meadows and reduce dairy production. These forces now threaten the economic and ecological sustainability of alpine meadows in NW Yunnan.