Effects Of Disturbance On Meadow Degradation And Meadow Ecosystem Services,in The Yak Park Of Mt.Jade Dragon,Yunnan

With the rapid development of tourism industry,the contradiction between effective protection and rational development has become increasingly prominent.There are some other primary disturbance activities in many eco-tourism scenic spots in addition to the interference of the tourism.The superposition of these disturbance activities will certainly cause more serious effects on local ecological environment.However,few studies have quantified the different disturbance activities in a unified way before discussing the impact of disturbance on vegetation influence.Mt.Jade Dragon is an important area for distribution of biodiversity in Northwest Yunnan and the core area where the species of alpine plants in Hengduan Mountains are the most concentrated.This tourism scenic spot is vulnerable to disturbance because of special geographical location and large numbers of tourisms.Meanwhile many uncertainties exist in the influence of disturbance at this spot.It is worth to study the pattern and magnitude of influence of disturbance on alpine meadow in this region accordingly.Based on remote sensing images in 2016 and field survey data from 2012 to 2018(data missed in 2017),a quantitative model of disturbance was established to determine the pattern of grazing disturbance,tourism disturbance and compound disturbance in the study area.Variance decomposition method was employed to determine the contribution rate of different disturbances to meadow degradation.Six functional traits,plant height,reproductive mode,seed size,flowering period,ornamental and palatability were selected to classify plant functional groups by WARD minimum variance clustering,and the spatial distribution characteristics of plant functional groups in the study area were analyzed.The impact of landscape composition on grassland ecosystem services was discussed from two aspects including landscape composition and landscape structure.In this way,the disturbance characteristics and its impact on the meadow in the region was quantitatively revealed.According to the degradation of the meadow,the distribution characteristics of plant functional groups and the characteristics of ecosystem services in the region,it is easier to guide administration to formulate scenic area management strategies which can promote the protection of biodiversity,tourism,leisure and entertainment,and the production and life of residents in the region develop in a coordinate way.The main results are showed as follows:(1)Grazing disturbance centrally distributed in the northwest region,and the drinking water point of livestock is the center of grazing disturbance;tourism disturbance acts more in the vicinity of scenic spots and temples.Distribution of disturbance activities coincides with the path system.The pattern of tourism disturbance is determined by the pattern of runway layout and behavior diffusion of tourists;the intensity of compound disturbance in the study area decreases from southeast to northwest.(2)The effect of disturbance on meadow degradation shows obvious gradient and spatial characteristics.The degradation degree of meadow increased with the grazed and tourism disturbance intensity increasing.In the grazing concentrated area,grazing disturbance was the main interference factor,with the highest contribution rate 61.56%.In the tourism concentrated area,tourism disturbance was the main interference factor,with the highest contribution rate 53.77%.In the whole region,the contribution rate of tourism disturbance to meadow degradation is higher than that of grazing disturbance.Tourism disturbance is the main cause of meadow degradation.(3)Different disturbance caused different changes in the landscape pattern of alpine meadow.Grazing disturbance made the landscape heterogeneity of slightly degraded meadows more serious,and the distribution of moderately and severely degraded meadows more concentrated.Tourism disturbance increased the fragmentation of severely degraded meadows,and made the distribution of mildly degraded meadows and moderately degraded meadows more concentrated.Compound disturbance aggravated the landscape heterogeneity of non-degraded meadows,and made moderately and severely degraded meadows concentrated outward diffusion.(4)Meadow ecosystem services are different under different disturbance.Tourist density and aboveground biomass index in the core area of tourism disturbance are higher,mainly providing cultural services of tourism and recreation,provision services of grassland productivity.The above-ground biomass,visitor density and yak density index are higher in the interference interaction area,mainly providing provision services,cultural services of tourism and recreation.Yak density and aboveground biomass index were higher in grazing disturbance core area,which mainly provided provision services.Regulation and support services also accounted for a high proportion(5)Overall,the impact of landscape composition on ecosystem services in the study area is significantly higher than that of landscape structure.Among them,the patch density index has the highest impact,indicating that the degree of landscape fragmentation caused by disturbance has the most profound impact on grassland ecosystem services in the study area.