京津冀“生态系统服务转型”及其空间格局

以1980年、2000年、2015年土地利用类型、NPP和统计数据为基础,运用GIS和生态系统服务价值测算方法,分析京津冀食物生产与固碳释氧两种服务的变化及其空间格局,揭示“生态系统服务转型”的原因。结果表明:（1）35年来,京津冀土地利用变化以建设用地扩张和耕地减少为主。1980年和2000年,NPP的高值区主要位于山区,2015年NPP的高值区主要位于平原。（2）1980-2000年京津冀生态系统服务变化以食物生产服务增加与固碳释氧服务降低为主,2000-2015年京津冀以食物生产服务与固碳释氧服务同时增加为主。“生态系统服务转型”模式为“食物生产+固碳释氧–”→“食物生产+固碳释氧+”。（3）农业生产力提升、林地面积与质量和耕地质量、草地质量提升是“生态系统服务转型”的主要原因。

Ecosystem services transition in Beijing-Tianjin-Hebei region and its spatial patterns

Land use changes can affect the ecosystem services. Since the implementation of reform and opening-up policy in 1978, the transformation and development of society and economy has led to the land use transition, and furthermore led to the "ecosystem services transition". Based on the data of LUCC, net primary productivity (NPP) and statistics in 1980, 2000 and 2015, this paper analyzed the changes and spatial patterns of two types of ecosystem service, e.g., food production, carbon sequestration and oxygen release, in the Beijing-Tianjin-Hebei region by using the methods of GIS and ecosystem service values calculation, and revealed the reasons for the "ecosystem services transition". The results show that: (1) In the past 35 years, the land use changes in the study region was mainly characterized by the expansion of construction land and the decrease of cultivated land. The phenomenon of conversion of cultivated land to construction land was particularly prominent in this region. Between 1980-2000 and 2000-2015, the cultivated land in mountainous areas changed from decrease to increase and the forest land changed from decrease to increase. The cultivated land in dam areas continued to increase and the forest land changed from decrease to increase. Both the cultivated land and forest land in plain area continued to decrease. In 1980 and 2000, areas with high values of NPP were mainly located in mountainous areas, and in 2015, they were mainly found in plain areas. (2) From 1980 to 2000, the ecosystem services in the study area were mainly reflected by the increase of food production service and the decrease of carbon sequestration and oxygen production service. From 2000 to 2015, the ecosystem services in the region were mainly featured by the simultaneous increase of food production function and carbon sequestration and oxygen production function. The pattern of "ecosystem service transition" was "food production + carbon sequestration and oxygen production -" → "food production + carbon sequestration and oxygen production +". (3) The main reasons for "ecosystem services transition" were the improvement of agricultural productivity, the increase of area and quality of forest land, and the increase of the quality of cultivated land and grassland. In general, the "ecosystem services transition" in the Beijing-Tianjin-Hebei region has a positive impact on food security. It is particularly necessary to pay attention to areas where both food production function and ecological function declined. Policies aimed at improving agricultural productivity should be formulated, while policies for supporting ecological restoration should be continued.