|Type de publication||Thesis|
|Type de mémoire||Master|
|Université||University of Michigan|
|Nombre de pages||87|
Dr. Kathleen Bergen
Dr. Kathleen Bergen
Dzud is a natural disaster endemic to parts of Central Asia and fairly unknown outside of the region. During spells of severe winter weather, livestock population suffers debilitating death from starvation and cold, which exacts enormous economic losses to nomadic herders and the society at large. Focusing on dzud outbreaks between 1993 and 2004 in Mongolia, I explored environmental and anthropogenic factors that contribute to geographic distribution of dzud impact and evaluate success of classical and spatial regression models to predict dzud mortality. Four regression methods were tested including ordinary least squares regression, spatial autoregressive models, geographically weighted regression, and recursive partitioning.
Regional heterogeneity in patterns of livestock mortality and contributing factors, as well as low efficiency of regression models, suggest that a single-model framework of analysis and non-normalized explanatory variables tend to perform poorly. The recursive-partitioning results demonstrate that the presence of several distinct ecological biomes within the territory of Mongolia create non-stationary and non-linear relationships between factors and livestock mortality. Diversity of ecological conditions drives regional predisposition for different types of dzud, most notably white dzud in mountainous and northern parts of Mongolia and black dzud in the Gobi desert.
The comparison of dzud episod es of 1993 and 2000-2003 revealed that an additional contributing factor unaccounted in previous modeling exercises of dzud is the long-distance mobility of herders as a main strategy for risk mitigation. While it is a necessary adaptation for livestock management in arid grasslands, under contemporary conditions of high livestock density it has an unexpected effect of spreading dzud vulnerability into unaffected areas, which may have contributed to development of multi-annual dzud episodes such as the one that occurred in 2000-2003. Since the transition of Mongolia to free-market economy, the vulnerability of herders to dzud has increased against a backdrop of exploding livestock population, a dysfunctional system of rangeland management, and withdrawal of government-run disaster preparedness programs.