Landscape change in southwest China's Himalayan Mountains: Implications for old-growth forests, alpine meadows, and avian diversity.

摘要

Land use and land cover change (LULCC) is the main cause of biodiversity declines worldwide. Many of the remaining high-diversity ecosystems are located in developing countries, which are experiencing rapid economic development, population growth, conservation activity and climate change. These drivers interact at multiple spatial and temporal scales to form complex LULCC dynamics, with unexpected consequences for biodiversity.;My overarching goal was to identify effective conservation strategies in developing countries. To this end, I studied land cover change, its drivers, and implications for biodiversity in northwest (NW) Yunnan, a biodiversity hotspot in the remote Chinese Himalayas. First, I used advanced remote sensing analysis to understand the consequences of the logging ban and ecotourism development for China's remaining old-growth forests. I found that clearing of high-diversity old-growth forest accelerated, from approximately 1100 hectares/year before the logging ban (1990 to 1999), to 1550 hectares/year after the logging ban (1999 to 2009). Paradoxically, old-growth forest clearing accelerated most rapidly where ecotourism was most prominent. Second, I analyzed change in alpine meadows, which have exceptionally high species richness, beta diversity, and endemism. I found that, between 1990 and 2009, at least 39% of alpine meadows converted to woody shrubs. The patterns of change suggest that a catastrophic regime shift is occurring, driven by feedback mechanisms involving climate change, environmental policy that prohibited intentional burning and economic development that increased grazing pressure. Finally, I studied the role of Tibetan sacred forests for avian biodiversity, and found that sacred forests protected old-growth forest ecosystems, supported a significantly different bird community than the surrounding matrix, and had higher bird species richness at multiple scales.;In general, my dissertation shows that complex interactions between environmental policy, economic development strategy, and climate change in tightly coupled human-nature systems can lead to unexpected trajectories of land cover change. Satellite imagery, when paired with ecological field data, can measure these broad-scale changes and their implications for biodiversity, thereby informing policy and management in a timely manner.