Dissertation Abstract

Cascading effects of changing climate and land use on alpine ecosystems and pastoral livelihoods in central Tibet

Hopping, Kelly A  2015  https://profiles.stanford.edu/kelly-hopping

Graduate Degree Program in Ecology, Colorado State University (United States), 208 pp.

Changing climate and land use practices are re-shaping the dynamics of social-ecological
systems globally, with alpine regions and subsistence-based communities likely to be among the
most vulnerable to the impacts of these changes. The Tibetan Plateau exemplifies a system in
which climate warming and projected increases in snowfall, coupled with natural resource
management policies that reduce livestock herd sizes and mobility, will have cascading effects not
only on the livelihoods of local pastoralists, but also on other globally important ecosystem
services that Tibet’s alpine meadows provide. To improve our understanding of the impacts of
altered climate and grazing restrictions in central Tibet, I conducted interviews with local herders
about their knowledge of environmental changes and the ways in which this knowledge is
produced and transmitted within the community, performed a 5-year climate change and yak
grazing experiment, and carried out observational measurements in plant communities around the
landscape. I found that herders are well attuned to the changes that are the most threatening to
their livelihoods, and they transfer this knowledge of environmental change within their village
primarily as a means for seeking adaptive solutions, rather than for learning from others. Results
from the experiment and landscape observations corroborate much of the herders’ understandings
of the factors driving undesirable changes in the alpine meadows. From the experiment, I found
positive feedbacks between yaks, vegetation, and nitrogen cycling, indicating that these meadows
are well adapted to moderate grazing under ambient climate conditions. However, they are particularly sensitive to warming-induced reductions in soil moisture. Although decreased plant
production and ecosystem CO2 fluxes with warming were partially mitigated by additional snow
before the start of the growing season, results from the landscape observations suggest that in the
longer term, climate warming will likely decrease the quantity and quality of forage available to
livestock and wildlife, while also reducing the carbon sink strength of alpine meadows in central
Tibet. Therefore, my results indicate that instead of continuing to mandate livestock removals,
which will do little to reverse undesirable ecological trends, more consideration needs to be given
to climate change adaptation strategies for pastoral social-ecological systems in Tibet.