Response Of Alpine Meadow To Trampling In Yak Meadow Park Of Mt. Jade Dragon

Mt. Jade Dragon is located at the northwest of Lijiang Yunnan province, China. It is a part of the Hengduan Mountains, which is one of three diversity centers of China. Alpine meadow is an important ecosystem and an eco-tourism resource for this region. Yak Meadow Park is a typical alpine meadow, and an important part of the Mt. Jade Dragon scenic area. The best time for alpine tourism is between May and September. It just as the meadow vegetation is in growing season. Due to the increasing number of tourists and the short-term trampling from tourists, the disturbance on the alpine meadow becomes increasingly serious. The trampling would damage plant structure and tissue, reduce vegetation coverage and height. Furthermore, it is also one of the main driving forces for meadow vegetation and soil degradation.To understand the purposes of alpine meadow communities and species to short-term trampling disturbance, we carried out a field experiment in Yak Meadow Park from June 2014 to August 2015. Then we used the relational model between trampling intensity and relative vegetation coverage (RVC) to quantify the resistance and resilience of the meadow. According to the results of field survey, we searched some plant functional traits that might associate with the trampling disturbance, such as life form, growth type, plant height, morphology characteristic, leaf size and reproduction plant functional traits. Based on above data, we explored the species and communities response differences to trampling disturbance that caused by plant functional traits. Finally, we compared these two methods and results of the meadow species and communities on the study area.The main results are summarized as follows:(1) The results of trampling simulation experimentalThe trampling intensity and the weight of trampler both had significant effects on the community coverage. The weight effects on the coverage were different in magnitude bur there were a same responses pattern. Community coverage was no significant change in 0 (control zone),50 passes,100 passes and 200 passes. However, community coverage declined sharply when trampling intensity larger than 200 passes. The community height was no highly significant variation at each trampling intensity.The results of the relation model showed that liner and curvilinear regression model can be used to describe the relationship between the vegetation coverage and the trampling intensity. And in most cases, second-order polynomials provided a better fit.The weight of trampler had significant effects on the resistance and resilience of the meadow. The trampling intensity in the 50 kg plots were great than that in the 70 kg plots, which might result in decline of community or species coverage over 50%. On the other hand, the recovery of community after a year was better in the 50 kg plots than that in the 70 kg plots.(2) The results of plant functional traitsThe differential functional traits of plants might result in the different responses of community and species to trampling in this study. Plants with morphology of short, rosettes, cluster or prostrate usually might have a high resistance, which usually associated with the functional traits of grasses and sedges. On the contrary, the plants with morphology of prominent height or erect might have a low resistance. Resilience could be predicted largely on geophyte and tussock, which usually associated with the functional traits of sedges.Correlation analysis between the functional traits and responses to trampling of species showed that the SDR of species with a morphology of small, rosette and cushion increased with the intensity of trampling. However, the SDR of species which belong to hemicryptophytes, geophytes, grasses, forbs, tall plant, tussock, erect plant and reproduction mainly by seed, decreased with the intensity of trampling. The SDR of other species with residual trait attributes were neutral to the trampling.The changes of the apparent characteristics such as plant coverage, height could be measured directly in our simulation trampling experiment. These changes reflected the responses of community and species to trampling. The relationship between plant functional traits and trampling further explained the inherent reasons in differential responses of community and species. Although the two methods started from different perspectives, the two results were similar. It indicated that it is a desirable perspective to explore the response of community and species to trampling, from the plant functional traits. Quantitative studies in plant functional traits will need to intensify in the future.This study clarified the responses of the vegetation to disturbance of tourism trampling. Meanwhile, based on the findings and the situation of Yak Meadow Park, we made some suggestions to improve management of alpine meadow. The results of the experimental study of the article may provide a reference for the other similar researches.