Effect of ecological restoration and climate change on ecosystems: a case study in the Three-Rivers Headwater Region, China

Abstract

The Three-Rivers Headwater Region (TRHR) is the headwater of the Yangtze River Basin (YARB), Yellow River Basin (YRB), and Lancang River Basin (LRB); it is known as China's 'Water Tower' owing to its important supply of freshwater. In order to assess ecosystem changes in the TRHR during 2000-2012, we systematically and comprehensively evaluated a combination of model simulation results and actual observational data. The results showed the following: (1) Ecosystem pattern was relatively stable during 2000-2010, with a slight decrease in farmland and desert areas, and a slight increase in grassland and wetland/water-body areas. (2) A warmer and wetter climate, and ecological engineering, caused the vegetation cover and productivity to significantly improve. (3) Precipitation was the main controlling factor for streamflow. A significant increase in precipitation during 2000-2012 resulted in an obvious increase in annual and seasonal streamflow. Glacier melting also contributed to the streamflow increase. (4) The total amount of soil conservation increased slightly from 2000 to 2012. The increase in precipitation caused rainfall erosivity to increase, which enhanced the intensity of soil erosion. The decrease in wind speed decreased wind erosion and the frequency of sandstorms. (5) The overall habitat quality in the TRHR was stable between 2000 and 2010, and the spatial pattern exhibited obvious heterogeneity. In some counties that included nature reserves, habitat quality was slightly higher in 2010 than in 2000, which reflected the effectiveness of the ecological restoration. Overall, the aforementioned ecosystem changes are the combined results of ecological restoration and climate change, and they are likely a local and temporary improvement, rather than a comprehensive and fundamental change. Therefore, more investments and efforts are needed to preserve natural ecosystems.

Assessing the effects of ecological restoration approaches in the alpine rangelands of the Qinghai-Tibetan Plateau

“…Therefore, implementation of the ecological restoration programs has increased vegetation coverage and mitigated further degradation of the grasslands (also reported by Cai et al 2015). However, due to ecological fragility of the area, the grasslands with low and very low vegetation coverage is still vulnerable to both natural and human disturbance (Jiang and Zhang 2016, Sun et al 2016, Shao et al 2017. Spatial variations of vegetation coverage change were observed among the counties studied (figure 2 and supplementary appendix figure S2).…”

Grassland ecosystem responses to climate change and human activities within the Three-River Headwaters region of China

“…Observation points for each variable at the small watershed scale were selected for 1988, 1995, 2000, 2005, 2008, and 2012. Grassland NPP data for each small watershed within the TRHR were obtained from the Remote Sensing Monitoring Atlas for the Qinghai River Headwaters Ecosystem 34 , while annual average temperature, precipitation, and hours of sunshine at each time point were extracted from the dataset of daily climate data from Chinese surface stations for global exchange (V3.0) 79 . Grassland area proportions at each time point were provided by the Center for Resources and Environmental Sciences, Chinese Academy of Sciences ( http://www.resdc.cn ) 80 .…”

“…The soil attribute information used in this study was extracted from the Harmonized World Soil Database V1.2 81 , while average distances between small watersheds and their nearest adjacent highway, water source, and provincial capital were used as location characteristic indices. Categorical variables included grassland types and the presence of NNRs within small watersheds; these data were obtained from the Remote Sensing Monitoring Atlas for the Qinghai River Headwaters Ecosystem 34 .…”

“…Grasslands are the major components of ecological environments in the TRHR and provide numerous goods and services that are valuable to humans including soil conservation, C sequestration, and water retention. At the same time, the harsh environments that characterize this region mean that single and continuous alpine meadows are the dominant surface covering layer 34 ; this has resulted in a fragile ecological environment which is highly sensitive to changing climatic conditions 33 , 35 , 36 . A large body of recent work has demonstrated that the climate of this region has conformed to a ‘warm and moist’ trend over at least the last 50 years 33 , 37 , a situation which has proved highly beneficial for increasing grassland NPP 38 .…”

Hierarchical species distribution models in support of vegetation conservation at the landscape scale

“…The findings presented here are promising and suggest avenues for future research. In particular, hierarchical SDMs could be further evaluated and tested for their use in a variety of local conservation efforts (see Guisan et al., ), such as reintroduction programs (Araújo & Peterson, ), management of endangered plant species (Wang et al., ), species selection in vegetation restoration programs (Gastón et al., ), comparing various scale preferences in partnership with stakeholders (Hughes et al., ), forest management (Mateo et al., ), and, especially, in the development of local restoration programs in the context of climate change (Eitzel et al., ; Jiang & Zhang, ). The consequences of climate change for the application of vegetation restoration, in particular, need further investigation (Harris, Hobbs, Higgs, & Aronson, ).…”