三江源国家公园植被时空变化及其影响因子

Spatiotemporal variation of vegetation coverage and its affecting factors in the Three-river-source National Park

三江源国家公园对于区域生态环境和物种栖息地的保护具有重要意义。基于2000-2018年的GLASS植被覆盖度产品,使用线性回归和Hurst指数分析园区植被覆盖度的时空变化,并利用皮尔逊相关系数、残差分析法探究气候变化和人类活动对植被变化的影响。结果表明:三江源国家公园植被覆盖度较低,其均值为0.24;2000-2018年间,园区植被覆盖度呈轻微增加趋势;园区植被变化以增长为主,且其变化大都呈正向持续性;趋势变化与Hurst指数叠加分析发现,园区植被变化类型以持续性增长为主,占园区植被区总面积的61.33%;其他依次为持续性退化、未来变化不确定类型;降雨对园区植被变化影响最大,其次为温度,人类活动对植被变化的影响最小。近年来,园区的温度和降雨都呈增加态势,改善了区域植被的水热条件,促进植被生长。

The Three-river-source National Park is of great significance for the protection of regional ecological environment and habitats for many species.Based on the GLASS vegetation coverage products from 2000 to 2018,we used linear regression and Hurst index to analyze the spatiotemporal changes of vegetation coverage,and used Pearson coefficient and residual trend analysis to explore the impacts of climate changes and human activities on vegetation dynamics.The vegetation coverage of the Three-river-source National Park was low,with a mean value of0.24,which slightly increased during the period 2000-2018.The vegetation coverage in most areas of the park was increasing,and most of which showed positive sustainable trends.Based on the overlay analysis of trend change and Hurst index,the sustainable growth of vegetation was predominant(61.34%),followed by continuous degradation and uncertain types in future change.Precipitation was the primary factor driving the changes of vegetation coverage,followed by temperature.Human activities had the least impact on the changes of vegetation coverage.The increases of temperature and precipitation in recent years improved water and heat conditions,and consequently promoted vegetation growth.