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Grazing exclusion by fencing is the principal option to restore degraded grassland, but its effects on recovery and succession of vegetation are not clear, especially in high mountain areas. In this study, we aimed to fill this gap by assessing the effect of seven‐year grazing exclusion on vegetation and soil seed bank along an altitudinal gradient in northern Tibet, China. Species richness, Shannon‐Wiener index and Simpson's diversity index of vegetation and soil seed bank, seed density, and the Sørensen index all displayed a mid‐domain (hump‐shaped) pattern with increasing altitude, except for the Shannon‐Wiener and Pielou indices of soil seed bank in fenced grasslands. These results demonstrated that the impact of grazing exclusion on the patterns of vegetation and soil seed bank change with altitude but are not synchronous. Grazing exclusion increased vegetation coverage but decreased soil seed bank density, and species diversity of vegetation and soil seed bank. The Sørensen index (0.03–0.2) and non‐metric multidimensional scaling (NMDS) analysis indicated that the species composition differed between vegetation and soil seed bank, but no difference was found between fenced and grazed grasslands. The low similarity suggests that the soil seed bank contributes little to vegetation recovery in alpine grassland. Seven‐year grazing exclusion had no effect on either vegetation succession or species composition of soil seed bank in alpine grassland. Overall, our findings suggest reconsidering the use of long‐term grazing exclusion to restore degraded grassland at high altitudes (above 4400 m above sea level) on the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Nutrient addition and grazing exclusion are effective methods to restore carbon and nitrogen pools in degraded grassland. However, how the combination of nutrient addition and grazing exclusion affect carbon and nitrogen pools through carbon and net nitrogen mineralization is unknown. A 56-day incubation study examined the effect of no additive (control — CK) and, the addition of sucrose (S), urea (U), sucrose + urea (SU), and yak dung (D) to the soil of grazed and fenced alpine grassland on carbon and net nitrogen mineralization. The 15N-tracer technique was used to determine nitrogen utilization by soil microorganisms. Nutrient addition with grazing exclusion increased soil organic carbon, microbial biomass carbon (MBC), inorganic nitrogen, and dissolved organic nitrogen (DON), and promoted carbon and net nitrogen mineralization in early incubation. The 15N recovery rate in soil was 4.5 to 21.7 % and decreased with time. Grazing exclusion altered the drivers of the carbon and net nitrogen mineralization rates, and increased carbon and net nitrogen mineralization rates by enhancing MBC and DON. The results indicated that nutrient addition: (1) decreased soil carbon and nitrogen stability by increasing nutrient availability and enhancing carbon and net nitrogen mineralization rates; and (2) in combination with grazing exclusion promoted carbon and net nitrogen mineralization. Consequently, soil carbon and net nitrogen mineralization depended on nutrient availability, and grazing stabilized soil carbon and nitrogen pools by reducing carbon and net nitrogen mineralization. The results could provide a theoretical basis for alpine grassland management. • Grazing exclusion in combination with nutrient addition promoted carbon and net nitrogen mineralization. • Nutrient addition affected carbon and net nitrogen mineralization indirectly by increasing nutrient availability. • Soil 15N recovery in fenced grassland was correlated positively with carbon and net nitrogen mineralization rates. • Short-term grazing exclusion reduced the stability of soil carbon and nitrogen pools. [ABSTRACT FROM AUTHOR]

• Land suitability evaluation assessed the suitability of land for urban development. • Intensive development of 3 urban growth boundary scenarios were simulated for 2040. • Landscape pattern of three urban growth scenarios were generated. • Intensive scenario is an ideal development mode. In designing national parks, it is important to balance land use with ecological protection and local socio-economic development. In the past decades, the national park has undergone landscape fragmentation and degradation of ecological functions due to climate change and land use change, especially in national parks with urban areas. Therefore, ecological environmental protection projects should include the assessment of land use when planning urban area development in the national park region. Consequently, we used the Land Suitability Evaluation (LSE) method, with 13 indicators for natural, social and ecological variables, to assess the suitability of the newly created national park for urban land use on the Tibetan Plateau. Combining results of the suitability assessment and the Cellular Automata (CA) method, three urban intensification scenarios were simulated for 2040: (1) unplanned, (2) intensified, and (3) strictly regulated urban growth boundaries (UGBs). The impact of land use on the normalized difference vegetation index (NDVI) was analyzed by remote sensing and GIS tools, and the landscape patterns of the three urban growth scenarios were calculated. Close to 87 % of the area was basically suitable, nearly 13 % was unsuitable, and only 0.06 % (43.4 km2–also included in the basically suitable) was suitable for urban land use. In 2040, the built-up areas are predicted to be 3.38, 2.71 and 2.32 times greater than in 2020 under the unplanned (without considering ecological restrictions), the intensive development (emphasizing the driving force of transportation and tourism on the expansion of built-up areas) and the strict control (maximizing ecological restrictions) scenarios, respectively. An ideal development model was used to balance ecological protection and population growth and economic development. The NDVI analysis revealed that the impact of land use on vegetation cover in the intensive development scenario was ranked as winter pastures > tourist development zones > summer pastures. It is concluded that the intensification scenario, with transport and tourism as the main spatial drivers, is the most desirable for the future coordination of ecological conservation and socio-economic development in the national park. This scenario may alleviate the current environmental pressure of livestock grazing on winter pastures in the national park on the Tibetan Plateau. However, realizing this model requires appropriate engineering design for town development. Future research should assess the impacts of urban growth on the ecological environment, with the aim to achieve sustainable urban development tailored to the various geographic regions. [ABSTRACT FROM AUTHOR]