Proposal No.: 0729786 PI Name: PETRAITIS, Peter S. PI's Institution: University of Pennsylvania Proposal Title: PIRE: Ecological and evolutionary effects of climate change and anthropogenic influences in Mongolia
This PIRE project examines the ecological, evolutionary and societal consequences of increased grazing pressures and rising temperatures in the Lake Hovsgol region of Mongolia. Climate models predict significant temperature increases in Mongolia. Increases in both temperature and the length of the growing season are already apparent in northern Mongolia, and this is of special interest to both scientists and governmental officials concerned with the impacts of climate change on the environment and the livelihood of local people. This PIRE project is a collaborative effort between ecologists, evolutionists and anthropologists at the University of Pennsylvania, Academy of Natural Sciences of Philadelphia, Mongolian Academy of Sciences, Mongolia University of Science and Technology, and National University of Mongolia. Advancing the training of undergraduates, graduate students and faculty from Mongolia and the U.S. is a major goal of the project and includes capacity building within the Mongolian scientific community and the training of U.S. students in a way that encourages their continued involvement in global research. The project develops an infrastructure that will enable long-term scientific exchanges to extend beyond the duration of the grant. It also provides a template for conducting international collaborative research and educational efforts in other regions facing rapid shifts in environmental conditions.
This project focuses on understanding the combined effects of grazing and climate change in a region that is used by nomadic herders and is home to two important ecosystems (the taiga forest and the steppe grasslands). The project integrates monitoring, experiments and modeling because of the complex interactions between climate change, land use by and movements of nomadic herders, and differences in ecosystem processes in taiga forests and steppe grasslands. Monitoring includes meteorological conditions, permafrost depth, hydrological cycles, ecosystem processes, and activities of nomad families and their livestock. Controlled experiments in the field examine how temperature increases and grazing affect plant community composition, phenology, productivity, litter decomposition and soil respiration. The project also addresses long-term responses of the forest ecosystem by examining carbon and oxygen isotope ratios of tree rings because long-term alteration of evaporative flux could affect regional precipitation and ecosystem sustainability. Modeling efforts emphasize the integration of results that can inform the development of new research questions, governmental policy and sustainable practices in the context of climate change. The research is of practical importance to the Mongolians, who are actively developing policy on land preservation and management, and to scientists worldwide, who strive to understand the future consequences of global warming.
The project is funded by the Office of International Science and Engineering (OISE) through the PIRE and the biocomplexity initiative and the Ecosystem Science cluster of the Division of Environmental Biology (DEB) in the Directorate of Biological Sciences (BIO).
This project focused on how human activities and climate change are altering the semi-arid steppe grasslands of northern Mongolia. The project was unique in that the steppe of northern Mongolia is one of the few intact ecosystems in the world lending a unique aspect to the project. With 30-40% of the population still living as nomadic herders, the use of steppe by Mongolians has remained essentially unchanged since the time of Genghis Khan. Even so, climate change in northern Mongolia has already lead to increases in temperature and has altered patterns of precipitation. Nomadic herders have started to alter their seasonal patterns of movement, grazing and haying in response to their perceptions of climate change. The research team, which included U.S. and Mongolian scientists, studied changes in plant communities and the cycling of carbon in the soil in response to climate warming and grazing. Herders were also interviewed about their perceptions of climate change and how they have changed their use of the steppe. The research was conducted at the International Long-Term Ecological Research (ILTER) site on the edge of Lake Hövsgöl, which is one of the 20 largest lakes in the world and drains into nearby Lake Baikal in Siberia. The major educational goal of the project was to train students on how to build international collaborative research efforts and to introduce participants to the major ecological and environmental issues facing Mongolia. Each summer over a period of five years, the project brought undergraduate students, graduate students, post-doctoral researchers and U.S. faculty members to the field site. Faculty from the National University of Mongolia also brought students, which promoted fruitful and productive exchanges among students and faculty. Undergraduate students were involved in hands-on research activities, which included working as part of on-going research projects and on their own independent projects. Over 100 students and faculty participated in the project. Based on extensive interviews with families of nomadic herders, 85% believe changes in weather have had the largest impact on their herds and livelihood. Almost 50% believe the weather has become more unpredictable, thus making it more difficult to predict extreme conditions and to know how to prepare for future conditions. Many said when they were children, the rains were very light, warm, and would last two or more days. In contrast, summer rainfall now arrives mostly during thunderstorms, which are short (lasting only 5 to 30 minutes) and intense. The water from these heavy showers is mostly lost as run-off. Herders believe the shift in rainfall patterns has led to the steppe being less productive. The research team’s analysis of data from 1960 to 2012 on the frequency of thunderstorms recorded at meteorological stations near Lake Hövsgöl supports perceptions of herders that the frequency of the brief heavy rains has increased. Results from the experimental studies, in which temperature, grazing, and rainfall were manipulated over four years, are also consistent with the perceptions of herders about the relationship between productivity and rainfall. Productivity, the timing of flowering, the cycling of carbon, and the composition of plant communities were adversely affected by experimental increases in temperature and shifts in rainfall, which were manipulated by watering some of the experimental plots. Changes in water availability due to year-to-year variation in rainfall and supplemental watering had large effects on productivity and plant composition that were intensified by changes in temperature and grazing. The overarching conclusion of the research is that climate change mostly via changes in rainfall patterns will have major impacts on the productivity and plant composition of the Mongolian steppe, which in turn will affect the livelihood of the nomadic herders.
