Changes in soil properties along grazing gradients in the mountain and forest steppe, steppe and desert steppe zones of Mongolia

Includes bibliographical references.Presented at the Building resilience of Mongolian rangelands: a trans-disciplinary research conference held on June 9-10, 2015 in Ulaanbaatar, Mongolia.Recent debates about the condition of Mongolia's rangelands and possible causes of rangeland change highlight the need for greater understanding of changes in grassland soil fertility and physical characteristics associated with grazing. As part of a large observational study of grazing effects on different Mongolian ecological zones and soil types (ecological sites), we studied soil characteristics along grazing gradients from winter shelters in the mountain and forest steppe, steppe and desert steppe ecozones of Mongolia. Our objective was to determine how grazing affects soil properties in winter pastures in different ecological zones and ecological sites within zones, based on grazing gradients. Our findings did not support our hypothesis that livestock grazing along a grazing gradient from winter shelters would lead to increased concentrations of nutrients (C, NO3-, P, K and humus) near the shelters. Instead, where soil chemical properties differed with distance, they were lowest close to winter shelters and higher with increasing distance. As hypothesized, we observed greater bulk densities nearer to winter shelters than farther away. Our hypothesis that grazing effects on soil properties would vary among ecological sites also was not supported. Further experimental and observational studies are needed to understand grazing effects on soil properties at different spatial scales and to examine feedbacks between livestock-induced changes in plant communities and soil quality

Time series analysis of satellite greenness indices for assessing vegetation response to community based rangeland management

Includes bibliographical references.Presented at the Building resilience of Mongolian rangelands: a trans-disciplinary research conference held on June 9-10, 2015 in Ulaanbaatar, Mongolia.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

Integrating herder observations, meteorological data and remote sensing to understand climate change patterns and impacts across an eco-climatic gradient in Mongolia

Includes bibliographical references.Presented at the Building resilience of Mongolian rangelands: a trans-disciplinary research conference held on June 9-10, 2015 in Ulaanbaatar, Mongolia.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