Warner College of Natural Resources

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https://hdl.handle.net/10217/195522

These digital collections include the materials from the Mongolia Project and datasets from the Warner College of Natural Resources.

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Open Access
Integrating herder observations, meteorological data and remote sensing to understand climate change patterns and impacts across an eco-climatic gradient in Mongolia
(Colorado State University. Libraries, 2015-06) Fernandez-Gimenez, M. E., author; Angerer, J. P., author; Allegretti, A. M., author; Fassnacht, S. R., author; Byamba, A., author; Chantsallkham, J., author; Reid, R., author; Venable, N. B. H., author; Nutag Action and Research Institute, publisher
Mongolia has one of the strongest climate warming signals on Earth, and over 40% of the human population depends directly or indirectly on pastoral livestock production for their livelihoods. Thus, climate-driven changes in rangeland production will likely have a major effect on pastoral livelihoods. We examined patterns of climate change and rangeland production over 20 years in three ecological zones based on meteorological records, remote sensing and herder observations. We found the strongest trends in both instrument records and herder observations in the steppe zone, where summers are getting hotter and drier, winters colder, and rangeland production is declining. Instrument records and herder observations were most consistently aligned for total annual rainfall, and consensus among herders was greatest for changes in rainfall and production and lowest for temperature changes. We found more differences in herder observations between neighboring soums within the same ecozone than expected, suggesting the need for more fine-scale instrument observations to detect fine-scale patterns of change that herders observe.
Open Access
Is overgrazing a pervasive problem across Mongolia? An examination of livestock forage demand and forage availability from 2000 to 2014
(Colorado State University. Libraries, 2015-06) Gao, W., author; Angerer, J. P., author; Fernandez-Gimenez, M. E., author; Reid, R. S., author; Nutag Action and Research Institute, publisher
Pastoral livestock production is considered a pillar of the Mongolian economy. Since the early 1990's, Mongolia has transitioned to a market economy, and livestock numbers have trended upward. Recent remote sensing studies have indicated widespread overgrazing; however, to date, no studies have examined grazing pressure on a national scale to assess the pervasiveness of overgrazing. We conducted a spatial and temporal analysis of grazing pressure by analyzing the relationship between livestock forage availability and forage demand across soums during 2000 to 2014. To estimate livestock forage demand (kg/ha/yr), we converted soum livestock densities to sheep forage units and calculated forage intake on an area basis. Forage availability was estimated using a regression relationship between herbaceous biomass and 250-m resolution MODIS NDVI (r2 = 0.70). The regression was applied to yearly maximum NDVI images to create surfaces of available forage (kg/ha/yr). Percent use (PU) of forage, which is the ratio of forage demand to forage available, was used as an indicator of grazing pressure. 50% use is generally recommended on rangelands for promoting forage regrowth and soil protection. Thirteen percent of the rangeland across Mongolia had PU that exceeded 50% during the entire time series, while 37% had 10 or more years with >50% use. Grazing pressure was higher in the central and western aimags, and lowest in the eastern aimags. Dzuds (winter disasters) in 1999-2002 and 2010 resulted in 35% and 22% reductions in livestock numbers nationwide. Grazing pressure exceeded 50% in over half of the country prior to and during dzuds due to the effect of summer drought on forage availability and high animal numbers. Grazing pressure was lowest after dzuds due to lower livestock numbers and forage response to higher rainfall. Our results indicate that heavy stocking (>50 PU) appears to be pervasive in about 32% of the country and consistent overgrazing (>=10 years with PU>=70) occurs on approximately 11% of the land area. During individual years, land areas having overgrazing are variable due to extreme climate events and linear increases in livestock numbers, regardless of forage availability, during periods between dzuds. The spatially explicit and temporal nature of these results will aid in disentangling effects of changing climate and management, and assessing the resilience of these rangeland systems in Mongolia.
Open Access
Time series analysis of satellite greenness indices for assessing vegetation response to community based rangeland management
(Colorado State University. Libraries, 2015-06) Angerer, J. P., author; Kretzschmar, J. K., author; Chantsallkham, J., author; Jamiyansharav, K., author; Reid, R., author; Fernandez-Gimenez, M. E., author; Nutag Action and Research Institute, publisher
After the transition of Mongolia's agriculture sector to a market economy in the early 1990's, community-based rangeland management (CBRM) organizations have been established across Mongolia to cooperatively manage rangeland resources. We hypothesized that rangeland ecoregions under CBRM would have greater biomass than ecoregions managed using traditional herder practices. We used time series analysis of AVHRR (8-km resolution, 1982 to 2012) and MODIS Normalized Difference Vegetation Index (NDVI) (250-m, 2000 to 2013) to calculate integrated NDVI (iNDVI) as a proxy for vegetation biomass. To address whether CBRM response is scale related, we created buffers of increasing distance around livestock winter shelter locations in soums where CBRM programs had been initiated and soums without formal programs. Spatial averages of iNDVI were calculated within buffer boundaries for each location, stratified by ecological zone. A repeated measures mixed model with yearly rainfall as a covariate was used to test for differences in iNDVI for CBRM status over time for buffer distances of 1, 2, 5, 10, and 30 for MODIS, and 10 and 30 km for AVHRR. In general, results were similar across buffer distances indicating that average vegetation response was similar for distances greater than 1 km around sampling sites. For MODIS NDVI, sites in the Desert Steppe and Eastern Steppe did not have significantly higher productivity in CBRM managed soums over time, regardless of buffer size. Mountain and Forest Steppe (MFS) locations had higher iNDVI in non-CBRM sites throughout the time series for both NDVI data sets, although these differences were not statistically significant. CBRM sites in the Steppe zone had higher iNDVI throughout the time series for both MODIS and AVHRR. Given that these differences occur throughout the AVHRR time series, they do not appear to be the result of CBRM activities. Our findings indicate that differences in vegetation response as a result of CBRM activities were not detected during the time series using productivity proxies from satellite imagery. In addition, the MODIS time series may be too short for detecting CBRM differences since it does not include data prior to when most CBRM programs were implemented.

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Browsing Warner College of Natural Resources by Author "Angerer, J. P., author"

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