| Title | Ecological consequences of shrub encroachment in the grasslands of northern China |
| Authors | Zhou, Luhong Shen, Haihua Chen, Leiyi Li, He Zhang, Pujin Zhao, Xia Liu, Taoyu Liu, Shangshi Xing, Aijun Hu, Huifeng Fang, Jingyun |
| Affiliation | Chinese Acad Sci, Inst Bot, State Key Lab Vegetat & Environm Change, Beijing 100093, Peoples R China Univ Chinese Acad Sci, Beijing 100049, Peoples R China Chinese Acad Sci, Inner Mongolia Prataculture Res Ctr, Hohhot 010031, Peoples R China Peking Univ, Inst Ecol, Coll Urban & Environm Sci, Beijing 100871, Peoples R China Peking Univ, Key Lab Earth Surface Proc, Minist Educ, Beijing 100871, Peoples R China |
| Keywords | Heterogeneity Relative interaction intensity Regional scale Shrub patch Structure Vegetation transition |
| Issue Date | 2019 |
| Publisher | LANDSCAPE ECOLOGY |
| Abstract | ContextShrub encroachment is a critical environmental issue in arid and semi-arid landscapes. However, due to the complicated effects of shrub characteristics and environmental variables, ecological consequences of shrub encroachment significantly differ in different regions. As a result, although the phenomenon of shrub encroachment is widespread in the grasslands of northern China, its ecological consequences and associated drivers have not been well documented at the regional scale.ObjectivesWe explored the effects of shrub encroachment on ecosystem structures (herb richness and abundance) and functioning (above- and belowground biomass, and soil carbon and nitrogen content) and evaluated the relative importance of climatic variables (temperature and precipitation) and shrub characteristics (cover, area, and height) as drivers of these effects.MethodsBased on field data from 53 sites that stretch across approximately 3000km in northern China, we conducted the relative interaction intensity (RII) of the response variables between shrub patches and grassy matrix, and then used the structural equation modeling (SEM) to assess the relative importance of chosen drivers on the ecological consequences.ResultsShrub encroachment increased the landscape heterogeneity by decreasing the richness, abundance and aboveground biomass of herbs, while by increasing the soil carbon and nitrogen content. The SEM explained 25-43% of the variation in shrub characteristics and 5-34% of the variation in the effects of shrub encroachment. Shrub height had greater effects on the RII of herb richness, soil carbon and soil nitrogen content, and the standardized total effects were 0.48, 0.25 and 0.18, respectively. Precipitation and temperature positively affected the impacts of shrub encroachment on herb richness, abundance, biomass, and multi-indexes. However, the direct effects of climate could be partially mediated by indirect effects via shrub characteristics.ConclusionsThe height, size and cover of shrub patches significantly influenced the community structures and functioning of grassland ecosystems. The increasing aridity could potentially exacerbate the negative consequences of shrub encroachment in arid regions. Our results also demonstrated that the effects of climate variables on grassland ecosystems could be mediated by shrub management. |
| URI | http://hdl.handle.net/20.500.11897/552082 |
| ISSN | 0921-2973 |
| DOI | 10.1007/s10980-018-0749-2 |
| Indexed | SCI(E) EI |
| Appears in Collections: | 城市与环境学院 地表过程分析与模拟教育部重点实验室 |
