汾河上游流域生态系统服务变化及驱动因素

随着社会经济的发展,人类对生态系统服务选择的加剧,生态系统服务面临的形势更加严峻。以汾河上游流域为研究区,以遥感影像、气象、土壤、统计数据及专题地图等为数据源,基于Arc GIS平台,采用CASA、In VEST等模型,评价了2000年和2008年汾河上游流域泥沙截持、产水量、NPP、固碳释氧、粮食生产五项生态系统服务变化情况;同时,整合人口、居民点、道路定量评价了研究区2000和2008年人类活动强度,并采用SPSS典型相关分析方法(CCA),对生态系统服务的自然与人文驱动因素进行了分析。结果表明:2000—2008年间,研究区5项生态系统服务变化明显。其中,泥沙截持服务减少43.30 t/hm~2,减少范围占整个流域87.5%,只有北端局部区域有所增强;产水服务增加4.74 t/hm~2,产水服务增加的区域占到了流域总面积的89.6%; NPP生产服务增加0.86 t/hm~2,NPP增加的区域占研究区的93.7%,仅边缘零星区域NPP减少;固碳释氧服务与NPP生产服务呈现一致的时空格局,增加量达2.18 t/hm~2,仅流域边缘零星分布减少的斑块;粮食生产服务总体上有所降低,下降幅度为15.65 kg/hm~2,粮食生产减少的区域占到整个流域的65%。同期,该区域人类活动强度有所增强,人类活动指数(HAI)由0.19增加到0.21,呈现出北低南高的空间格局。相关性分析表明,2000—2008年前,人类活动与泥沙截持和产水服务呈现极显著的正相关(r=0.637**和r=0.656**)。典型相关分析则(CCA)表明:影响泥沙截持服务的主要驱动因子是坡度,影响产水量的主要因素是降雨量和温度; 2000—2008两年间生态系统服务变化量的典型相关分析表明泥沙截持和产水服务受日照时数、相对湿度、降雨等自然因子的影响,NPP生产/固碳释氧的主要影响因子为温度和坡向。

Evolution of ecosystem services and its driving factors in the upper reaches of the Fenhe River watershed, China

Rapid, ongoing social and economic development and the increase in human selectiveness about their activities are challenging the provision of ecosystem services. This study investigated the upper reach of the Fenhe River watershed. Five ecosystem services (sediment retention, water yield, Net Primary Productivity NPP] production, carbon sequestration and oxygen production CSOP]) were analyzed along with grain production in 2000 and 2008. ArcGIS, CASA, and InVEST software were used to analyze remote sensing images, climatic and soil data, statistical data, and thematic maps. The human activity intensity analysis was based on population, residential site, and road network. An SPSS embedded canonical correlation analysis (CCA) was used to identify the physical and anthropogenic driving factors underlying the variations in ecosystem services. The results showed that between 2000 and 2008, sediment retention decreased by 43.30 t/hm² over 87.5% of the total area. The only exception was northern Ningwu County. Water yield increased by 4.74 t/hm² over 89.6% of the total area, and NPP production increased by 0.86 t/hm² over 93.7% of the total area. The only exceptions were small patches along the edges. The CSOP values had a pattern similar to the NPP values. They increased by 2.18 t/hm², but decreased in patches dotted along the edge areas. Grain production decreased by 15.65 kg/hm² over 65% of the total area. Human activity intensity (HAI) increased slightly from 0.19 in 2000 to 0.21 in 2008 and there was a low-north-high-south spatial pattern. HAI variations were positively correlated to variations in sediment retention and water yield (r=0.637^**, r=0.656^**, respectively). The CCA analysis showed that the main factor driving sediment retention is slope, whereas the main factors driving water yield are precipitation and temperature. The CCA for the difference between 2000 and 2008 showed that the physical factors of sun hours, relative humidity, and precipitation affected sediment retention and water yield, and that temperature and slope jointly affected the NPP and CSOP.