Impact of Meadow Degradation on Soil Water Status and Pasture Management—A Case Study in Tibet

Abstract

Alpine meadow dominated by Kobresia pygmaea forms both an important ecosystem and the main pasture resource on the Qinghai–Tibetan Plateau, and its degradation is detrimental to ecosystem health and the pastoral economy. This paper reports research on the impacts of possible degradation on soil and biological properties related to water status, as water availability is fundamental to grass productivity. It also considers herders' perceptions towards, and adaptation to, the changing environment. The research was carried out in and around Kema village in Nagqu Prefecture, Northern Tibet. The biotic and abiotic properties of the K. pygmaea meadow are significantly different in patches with diverse soil and vegetation combinations, which include normal meadow, crusted meadow, and bare soil. Change of species composition, low species diversity, coarsening of soil, and lack of soil moisture and organic matter are found under bare soil after erosion of the turf layer. Low infiltration rates and reduced dew deposition are found under crusted meadow. Herders have witnessed some aspects of the deterioration of meadow quality and have noticed some climatic variations. However, they do not consistently link changing meadow quality to climate change and rarely have a clear idea of what overgrazing is, as although their mobility has been reduced, they may think that they are still using pastures periodically as in transhumance. Adapting current privatisation policies by considering herders' traditions and needs, and balancing scientific knowledge with local perception and knowledge, will help to guarantee long‐term benefits through sustainable use of the fragile alpine meadow resource. Copyright © 2014 John Wiley & Sons, Ltd.

Long‐Term Grazing Alters Soil Trace Gas Fluxes from Grasslands in the Foothills of the Rocky Mountains, Canada

“…Globally, grazing by domesticated ungulates is a key human-driven activity that has resulted in land degradation and desertification (Cerdà & Lavee, 1999;Gillson & Hoffman, 2007;Li et al, 2011;He & Richards, 2015). In the foothills of the Rocky Mountains, long-term cattle grazing may degrade grassland soils (Johnston et al, 1971;Dormaar & Willms, 1998) and alter plant community composition (Willms et al, 1985).…”

Fate of Organic and Inorganic Nitrogen in Crusted and Non‐Crusted Kobresia Grasslands

“…pygmaea is well adapted to a moderate grazing intensity because of its specific plant traits, and thus it becomes the dominant species in this pastoral ecosystem (Miehe et al . ; He & Richards, ). For instance, K. pygmaea (i) forms thick root mats protecting against trampling by sheep and yaks (Cao et al ., ; Kaiser et al ., ; Miehe et al ., ; Unteregelsbacher et al ., ) and (ii) is very efficient for nutrient uptake because of its dense root network (Schleuss et al ., ).…”

“…The reason is that increasing grazing intensity reduces seedling emergence (Wang et al ., ), and disturbs reproduction of numerous grasses as well as changing soil physicochemical properties. Consequently, this stimulates the occupation of patches by blue–green algae and crustose‐lichen crusts (Eldridge, ; Unteregelsbacher et al ., ; He & Richards, ). Such crusts induced by overgrazing have been clearly observed in Kobresia grasslands on the Tibetan Plateau (Unteregelsbacher et al ., ; He & Richards, ).…”

Community-weighted mean traits but not functional diversity determine the changes in soil properties during wetland drying on the Tibetan Plateau

“…Previous studies have suggested that there may be a secondary successional change from swamp to swamp meadow and mature meadow and that soil water availability may be the main driver of this successional process (Ma et al, 2014;He and Richards, 2015;Lin et al, 2015). At the same time, plant functional traits play an important role in predicting the patterns of species composition, community structure, and their responses to environment change, which has drawn substantial ecological interest (e.g., Wright et al, 2004;McGill et al, 2006;Pérez et al, 2014;Li et al, 2015a); however, it is not clear whether functional traits and functional diversity (i.e., the identity, abundance, and range of species in a given community) can reflect the changes in soil properties during wetland drying on the Tibetan Plateau.…”