基于长时间序列的川西重点生态功能区生态系统状况及变化研究

Study on the status and changes of ecosystems in key ecological functional areas of western Sichuan based on long time series

重点生态功能区关系到一个区域的生态安全,通过2000—2015年生态系统分类数据和1990—2015年植被指数数据,运用生态系统类型变化动态度和植被指数年均合成等方法,对川西重点生态功能区的生态系统现状及变化进行研究。结果表明:川西重点生态功能区生态系统类型主要以森林、灌丛和草地生态系统为主,面积占整个区域的89.68%,3种生态系统的面积在2000—2015年间共增加了230.65 km 2。从变化剧烈程度来看,2010—2015年生态系统类型变化最剧烈,综合动态度为0.1%,为2000—2005年和2005—2010年的5倍,单个生态系统中城镇生态系统变化最剧烈,2010—2015年综合动态度为23.38%。从植被指数分布与变化结果来看,1990—2015年植被指数总体呈上升趋势,空间上呈东高西低的分布状况,其中1990—1996年和2010以后植被指数波动相对较大,主要由森林被大面积砍伐和自然灾害引起。整体上四川植被指数均值高于川西重点生态功能区,主要是因为川西西部多为高寒草甸草原,植被指数相对较低,而四川东部多为一年三熟制农作物,植被指数相对较高,最终导致川西植被指数均值小于整个四川省。

The key ecological functional areas affect the ecological security of a region.This paper is based on the ecosystem classification data from 2000 to 2015 and the vegetation index data from 1990 to 2015.By using the methods of dynamic change of ecosystem types and annual average synthesis of vegetation index,the present situation and changes of ecosystem in key ecological functional areas in Western Sichuan were studied.The results showed that forest,shrub and grassland ecosystems were the main ecosystem types in the key ecological function areas of Western Sichuan,accounting for nearly 89.68%of the total area,and the three ecosystems increased by 230.65 km 2 between 2000 and 2015.From the point of view of drastic changes,ecosystem types changed most dramatically in 2010—2015,with a comprehensive dynamic degree of 0.1%,five times as much as in 2000—2005 and 2005—2010.Urban ecosystem changes most dramatically in a single ecosystem,with a comprehensive dynamic degree of 23.38%in 2010—2015.From the results of vegetation index distribution and change,the vegetation index in 1990—2015 showed an overall upward trend,and the spatial distribution was high in the east and low in the west.The fluctuation of vegetation index is relatively large in 1990—1996 and after 2010,which is mainly caused by large-scale deforestation and natural disasters.On the whole,the mean vegetation index is higher than the key ecological function areas in Western Sichuan,mainly because the Western Sichuan is mostly alpine meadow steppe,and the vegetation index is relatively low.In the eastern part of Sichuan,most of the crops are three crops a year,and the vegetation index is relatively high.Finally,the average vegetation index in West Sichuan is smaller than that in the whole Sichuan province.