Alpine grassland degradation and its control in the source region of the Yangtze and Yellow Rivers, China

Abstract

Serious grassland degradation is endangering the environment of the source regions of the Yangtze and Yellow Rivers (SRYYR). There is an urgent need to analyze and review the grassland resources, status of grassland degradation, factors causing grassland degradation, and measures for grassland protection and restoration so as to ensure sustainable development in the SRYYR. This review shows that: (1) The alpine meadow, one of the most important grassland types in the SRYYR, can be divided into four subtypes: typical alpine meadow, alpine swamp meadow, alpine steppe meadow and alpine shrub meadow. (2) There is approximately 357.13 × 104 ha degraded grassland in this area, which is 34.34% of the area of all the investigated grasslands in the SRYYR, and heavily degraded grasslands cover an area of 74.34 × 104 ha, approximately 20.82% of the degraded grasslands. (3) Alpine grassland degradation in the SRYYR follows the following sequence: non‐degraded grassland → lightly degraded grassland → moderately degraded grassland → heavily degraded grassland. (4) Grassland degradation in the SRYYR is caused by the integrated effect of anthropogenic and natural factors. The principal factors causing grassland degradation are thought to be long‐term overgrazing and the destruction by rodents that follows, and climate warming, which accelerates the grassland degradation process. (5) Some effective management practices (e.g. rodent and ruderal weed control, establishment of artificial grassland, rational management of grassland, and optimizing livestock structure) and integrated countermeasures for the restoration of degraded grasslands have been developed in the SRYYR.

Response of vegetation and soils to desertification of alpine meadow in the upper basin of the Yellow River, China

“…our study also indicates that plant diversity decreases because fewer shrub species and forbs are able to adapt to coarse soil texture and sand burial than herbaceous species (Li 2000) and that reduces water-holding capacity of topsoil, which is unfavourable for the survival of herbaceous species (Shang et al 2006). Desertification of alpine meadow severely reduces vegetation coverage, and biomass of herbaceous plants and monocotyledon species, which are essential feed for livestock decrease, while dicotyledons unsuitable for animal consumption proliferate (Zhou et al 2005). in general, desertification not only decreases plant diversity but also constrains pastoral usage due to the reduction of herbaceous biomass and an increase of unpalatable species.…”

“…in the process of alpine meadow desertification, the amount of sedges decreases as a proportion of biomass, unpalatable plants gradually invade, and denuded landscapes in grasslands become obvious due to low vegetation cover, which increases the possibility of wind erosion. at this time, rodents frequently damage vegetation by excessive excavating and gnawing, and wind erosion impacts appear (Zhou et al 2005). These observations are in agreement with results from alpine steppe desertification in QinhaiTibet Plateau .…”

“…This runoff decline limits regional development and security (Wang et al 2000) and affects agricultural development in the mid and lower reaches of Yellow River. The current productivity of the alpine meadows in this region is approximately 30% less than the productivity measured only 2 decades ago (Zhou et al 2005). over the period, the native wild fauna has been greatly reduced, and nearly every medium-to-large mammal species is now classified as threatened (MacKinnon et al 1996;Wang & Fu 2004).…”

“…These changes clearly imply that the alpine meadow in this region is in danger of losing many of its native species, changing the balance of the grassland ecosystem, and reducing its ability to support sustainable pastoralism, the region's primary economic activity, due to desertification (Foggin & Smith 1996;Lai & Smith 1996). Responses to these ecosystem changes, local government and scientists have investigated the alpine meadow degradation process in order to restore alpine meadow (Zhou et al 2005). The objective of this study is to describe the changes of vegetation and soil properties and their relationship at the different stages of alpine meadow desertification.…”

Arbuscular mycorrhizal fungi in degraded typical steppe of inner Mongolia

“…However, numerous studies have indicated that overgrazing is one of the most important causal factors (Green, 1989;Zhou et al, 2002;Christensen et al, 2004;Zhou et al, 2005). Grazing by herbivores can substantially influence the dynamics of plant communities by altering primary production, decomposition of organic matter (OM), the cycling and distribution of nutrients and competitive relationships among plant species (McNaughton, 1985;Fahnestock and Detling, 1999).…”