HR: 0830h
AN: B51E-1018    [PDF]
TI: Changes in Mongolia Vegetation Productivity (1982-1998) Derived From Satellite Observations
AU: * Hicke, J A
EM: jhicke@nrel.colostate.edu
AF: Natural Resource Ecology Laboratory, Campus Box 1499 Colorado State University, Fort Collins, CO 80523-1499 United States
AU: Ojima, D S
EM: dennis@nrel.colostate.edu
AF: Natural Resource Ecology Laboratory, Campus Box 1499 Colorado State University, Fort Collins, CO 80523-1499 United States
AB: Mongolia is dominated by rangelands that are utilized by humans for livestock grazing. Pastoral systems apply pressure to vegetation productivity that already may be stressed by water limitation. Northern Eurasia appears to be undergoing dramatic climate warming during the past several decades that also impacts the ecosystem dynamics in the region. Ninety percent of Mongolia is vulnerable to desertification, and recent overgrazing in recent decades is thought to be responsible for land degradation. A shift around 1990 in the sociopolitical system from collectivization to privatization has likely impacted Mongolian rangelands. In this study, we used a two-decade-long time series of the normalized difference vegetation index together with a carbon cycle model to assess recent changes in net primary production (NPP). Over the entire country, NPP has increased slightly during the 1982-1998 period. Comparisons with a map of soil degradation reveals both increases and decreases in areas with severe degradation, and areas not identified by the map exhibit decreases. We compared NPP from the first half of the record (1982-1990) with that of the second half (1991-1998). NPP generally decreased more in the 1990s and was substantially more variable than in the 1980s. Changes in precipitation and possibly climate warming coupled with land-use change likely drive much of this behavior.
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2003 Fall Meeting