No abstract

Thirty years ago, Mongolia’s Gobi Desert was intact, roadless and had low traffic, and it was a refuge for many endangered and rare species. A large mining boom and significant livestock grazing are currently putting pressure on the desert. Mining products were transported by trucks on dirt (gravel) roads between 2000 and 2012. Emphasizing its importance in the Mongolian economy, a paved road was constructed in 2012 along the dirt road. Unfortunately, vegetation along the paved road was removed without restoration. In the desert, locals continue to use, create and extend dirt roads. The impact of these roads on the vegetation has yet to be studied. We estimated the spatial extent of the dirt-road corridors in three time intervals (the years 2010, 2015 and 2020) and evaluated the vegetation along both paved and dirt roads at three distances (100, 500, and 900 m) from the road. Within ten years, the length of paved roads and soil dirt roads nearly doubled, although the majority of them were developed and created between 2015 and 2020. A single track makes up around 42 percent of the soil road, whereas the remaining 58 percent are roads consisting of three to four tracks with an average width of 26.5 m. The vegetation along the paved road was lower in terms of species richness, canopy cover, and the basal gap between perennial plants and biomass, compared to the soil road. Although the effects of soil roads on the vegetation along the roads is less negative than the effects of the paved road, the corridors formed along the soil roads span a non-negligible area of pastureland in the region. The vegetation along the already-constructed paved road in the desert should be artificially reclaimed with the aim of expediting natural revegetation. Moreover, a “new legislation” is required to prevent continued degradation due to the ongoing creation and extension of soil road corridors by local populations in the desert.

Nitraria sibirica Pall. is a shrub species belonging to the family of Nitrariaceae. It plays pivotal role in arid ecosystems since it is tolerant to high salinity and drought. This species is widely distributed throughout Mongolia and it is mostly found in arid ecosystems of Mongolian Gobi Desert. In this study, we developed allometric equations for estimating aboveground biomass of N. sibirica using various structural descriptors and pinpointed the best models. Variables that precisely predicted above-ground biomass were a combination of basal diameter, crown area, and height. The allometric growth equation constructed is not merely helpful to achieve accurate estimations of the above-ground biomass in shrub vegetation in the Gobi Desert of Mongolia, but also can provide a reference for the above-ground biomass of Nitraria species growing in analogous habitats worldwide. Therefore, our research purposes an important advance for biomass estimation in Gobi ecosystems and complements previous studies of shrub biomass worldwide. This study provides reasonable estimates of biomass of N. sibirica, which will be valuable in evaluations of biological resources, especially for quantifying the main summer diet of Gobi bears, and also can be an alternative tool for assessing carbon cycling in Gobi Desert.

Shrub expansion has been widely documented in Northern Hemisphere due to the climate change and land use impacts. The fi ndings of some studies show that shrub expansion greatly corresponds with changes in temperature and precipitation in Arctic, whereas studies in Tibetan Plateau show that shrub expansion is more dependent on soil moisture. However, there has not been suffi cient studies of shrub expansion in Central Asia, including our country. We carried out studies on 12 shrub species present in Khar Yamaat Natural Reserve Area (N47.645727, E112.043829) to determine the response of several shrub species to climate factors and disturbances. We were able to distinguish diverse pore arrangements, various growth patterns, climate-growth relationships and fi nally, pointer years were recorded as well. That being the case, shrubs in Mongolia have successfully been proven to have a high dendrochronological potential and it is practicable to apply it for rangeland and ecological assessments.