scholarly journals Grazing Exclusion Changed the Complexity and Keystone Species of Alpine Meadows on the Qinghai-Tibetan Plateau

2021 ◽  
Vol 9 ◽  
Author(s):  
Yong Zhang ◽  
Qingzhu Gao ◽  
Hasbagan Ganjurjav ◽  
Shikui Dong ◽  
Qiuzhu Zheng ◽  
...  

Grazing exclusion is an effective approach to restore degraded grasslands. However, the effects of grazing exclusion on keystone species and the complexity of plant community were poorly investigated. Here, we conducted a field survey among different grazing exclusion durations, i.e., Grazing, grazing exclusion below 5 years, grazing exclusion with 5 years, grazing exclusion with 7 years, and grazing exclusion over 7 years, in alpine meadows on the central Qinghai-Tibetan Plateau (QTP). The complexity and keystone species of alpine meadows were analyzed by a network analysis. The results showed the following: (1) The species richness did not change, but aboveground biomass and the coverage of the plant community tended to increase with the extension of the grazing exclusion duration. (2) The soil nutrients, i.e., total nitrogen, total organic carbon, available nitrogen, and available potassium, remained stable, while the soil bulk density decreased under grazing exclusion conditions. (3) There was a hump-shaped change of the complexity (i.e., average connectivity and average clustering coefficient) of the plant community along with the extension of the grazing exclusion duration. Moreover, the keystone species were different among the grazing exclusion treatments. Based on the complexity of the plant community and the changes of keystone species, the optimum duration of grazing exclusion for alpine meadows should be between 5 and 7 years. Our results suggest that besides the productivity, the change of the complexity and keystone species of plant community should be considered when grazing exclusion is adopted to restore the degraded alpine meadows.

2014 ◽  
Vol 20 (3) ◽  
pp. 237 ◽  
Author(s):  
Peter J Berney ◽  
G. Glenn Wilson ◽  
Darren S. Ryder ◽  
R.D.B Whalley ◽  
John Duggin ◽  
...  

We examined the effects of grazing exclusion over a period of 14 years on the species richness and community composition of three plant communities with different dominant species and water regimes in the Gwydir Wetlands in eastern Australia. Responses to grazing exclusion varied among the three plant communities, and were most likely to be evident during dry periods rather than during periods of inundation. In frequently flooded plant communities, there was an increase in phytomass following exclusion of domestic livestock, but changes in plant community composition and species richness due to livestock exclusion varied depending on the morphological attributes of the dominant plant species. In a plant community where tall sedge species were dominant, livestock exclusion further increased their dominance and overall species richness declined. In contrast, where a prostrate grass species such as Paspalum distichum was dominant, species richness increased following livestock exclusion, due to an increase in the abundance of taller dicotyledon species. However, livestock exclusion in a community where flooding was less frequent and native grass species have been largely replaced with the introduced species Phyla canescens, resulted in no significant changes to phytomass, species richness or community composition among the grazing exclusion treatments over time. Our results indicate responses to exclusion of domestic livestock are dependent upon the dominant species within the plant community and will likely vary over time with the extent of wetland inundation. Grazing exclusion alone, without increased flooding, is unlikely to restore floristically degraded floodplain plant communities.


2018 ◽  
Vol 174 ◽  
pp. 92-98 ◽  
Author(s):  
Na Guo ◽  
Aidong Wang ◽  
A. Allan Degen ◽  
Bin Deng ◽  
Zhanhuan Shang ◽  
...  

Author(s):  
Lu Zhang ◽  
Xiangtao Wang ◽  
Jie Wang ◽  
Qian Wan ◽  
Lirong Liao ◽  
...  

2017 ◽  
Vol 7 (23) ◽  
pp. 10233-10242 ◽  
Author(s):  
Jacob Nabe-Nielsen ◽  
Signe Normand ◽  
Francis K. C. Hui ◽  
Laerke Stewart ◽  
Christian Bay ◽  
...  

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