| Grassland degradation is one of the serious ecological problems facing the Three-River Headwater Region.In order to restore the ecological environment of the Three-River Headwater Region,the Nature Reserve of the Three-River Headwater Region was established in 2000.The first phase of Three-River Headwater Region Ecological Protection and Construction was implemented in 2005,and the second phase of the Protection and construction was implemented in 2014.Therefore,it is of great significance for the ecological construction of the Three-River Headwater Region to grasp the change trend of the grassland in the Three Rivers Source and the driving factors of the grassland change before and after the establishment of the protected areas and the implementation of ecological protection.This article uses the time of the first phase of the Three-River Headwater Region ecological protection and construction started in 2005 and the second phase of the project started in 2014 as the discontinuities.It is divided into 2000-2005,2005-2013,2013-2019 and 2000-2019 monitoring time,based on the Sen+Mann-Kendall trend analysis method,to analyze grassland changes in the Three-River Headwater Region and in nature reserves of Three-River Headwater Region.The correlation analysis method is used to explore the response of climate factors and changes,and the residual trend method is used to isolate human activities and explore the impact of human activities on grassland changes.In addition,by integrating the grassland change trends,climate and human activities and grassland changes and related significance,the driving factors of grassland change areas are classified,and the contribution of climate and human activities to grassland changes in the Three-River Headwater Region is assessed.The research results show that:(1)From 2000 to 2019,52.08%of the grasslands in the Three-River Headwater Region showed an improvement trend,and only 1.66%of the grasslands showed a degeneration trend.From 2000 to 2019,in the grassland area of the Three-River Headwater Region,the area of obvious improvement was 15.82%,and the area of slight improvement was 36.26%.The area of obvious degradation is only 0.21%,and the area of slight degradation is 1.45%.The area with insignificant change accounts for 46.26%.Xing Hai County,Tong De County and Ze Ku County in the northeast showed a clear improvement trend.Grassland degradation in Da Ri County,Gan De County,Qu Malai County and Zhi Duo County is relatively large.(2)The implementation of the ecological protection project has promoted the improvement of the grassland,and the proportion of the area of improvement has greatly increased from 8.82%before the implementation of the project to about 25%during the implementation of the two-phase protection project.Before the implementation of the first phase of the Three-River Headwater Region Ecological Protection Project(2000-2005),9.60%of grassland degradation accounted for slightly higher than 8.82%of grassland improvement.In the first phase of the ecological protection project(2005-2013),the proportion of grassland improvement area increased significantly to 28.37%.In the second phase of the ecological protection project(2013-2019),the proportion of grassland improvement area tended to be stable(24.57%).In the first and second phases of the ecological protection project,the proportion of grassland degradation area continued to decrease.Measures such as livestock reduction,rodent and pest control,and pasture fences implemented by the Three-River Headwater Region Ecological Protection Project are significantly related to the improvement of grassland,and have played an important role in helping grassland improvement.(3)From 2000 to 2019,the area of grassland improvement in the protected area accounted for 57.40%,10 percentage points higher than that outside the protected area.In the early stage of the National Nature Reserve(2000-2005),8.62%of the improvement area in the protected area accounted for less than 9.41%outside the protected area,and 11.23%of the protected area degraded accounted for more than the outside of the protected area 9.35%.In the first phase of ecological protection(2005-201 3),the proportion of grassland degradation and improvement area in and outside the protection area reversed.The total degradation ratio in the protection area was 4.51%and less than 9.98%outside the protection area.It is also 6.20%higher than the type of improvement outside the protected area.The second phase of the ecological protection project(2013-2019),this good grassland change situation can continue.The ecological projects in the protected area are relatively concentrated,and combined with the establishment of the National Nature Reserve,the situation of "the grassland in the protected area is worse than that outside the protected area" is changed.(4)From 2000 to 2019,72.56%of the grasslands in the Three-River Headwater Region were significantly affected by climate or human activities,54.25%of grasslands in the Three-River Headwater Region were significantly affected by climate,47.22%of grasslands were significantly affected by human activities.48.13%of grassland improvement is caused by human activities and climate,and 1.43%of grassland degradation is caused by human activities.The proportion of grassland degradation caused by human activities in the reserve is slightly lower than 0.07%outside the protected area,and the proportion of improvement caused by human activities is slightly higher than 1.04%outside the protected area,and the protection of grassland improvement type caused by human activities There are three areas that are larger than the climate-induced improvement.Compared with non-protected areas,the positive effects of human beings in the protected areas are better and play a positive role in the restoration of grassland ecosystems. |
PDF Full Text Request