基于生态系统服务的中国陆地生态风险评价

传统的生态风险评价主要依据是点源性威胁、区域景观格局变化等生态实体特征指标,忽略了与实体功能属性密切相关的人类福祉因素。将生态系统服务纳入生态风险评价体系是一个新的研究思路。本文运用GIS和遥感技术重构了中国陆地生态系统服务的空间图谱,采用生态风险分析模型给出了基于生态系统服务的中国陆地生态风险格局的定量描述和空间分布,划定了不同置信水平下的生态风险管控优先区。结果表明：① 2000-2010年中国陆地生态系统年均总生态系统服务指数取值在0~2.17之间,年际间呈现小幅波动趋势,年平均总指数在0.30~0.57之间变化,其中24.7%的区域显著增加,主要分布在台湾、云贵高原及新疆西北内陆区,37.1%的区域显著减少,主要分布在东北、青藏高原及中东部地区;② 不同置信水平下的中国陆地生态系统服务存在的风险损失不尽相同。如当置信水平为90%时,总生态系统服务指数的可能损失比例为24.19%,生态风险指数为0.253。比较置信水平和生态风险指数间的关系,发现当置信水平较高时,生态系统服务蒙受风险的概率相应降低,但此时出现风险时所承受的损失也对应增加;③ 以90%置信水平为例,中国生态地理区划的风险特征表现为：平均生态系统服务风险指数居前列的六位依次为内蒙古高原生态区、华北平原生态区、黄土高原生态区、东北平原生态区、横断山生态区、青藏高原生态区,极重度风险所占区域面积比例依次为55.89%、26.63%、24.35%、20.62%、18.70%、25.12%。

Ecological risk assessment based on terrestrial ecosystem services in China

The ecological risk assessment was previously explored according to ecological entity characteristics, such as point source threat and regional landscape pattern change, and ignored the factors related to the human well-being. The academic contribution of the essay is to integrate ecosystem services into assessment system of ecological risk in a new perspective. In this paper, the spatial mapping of ecosystem services on China's land is reconstructed with the aid of GIS and RS. Moreover, the ecological risk analysis model is established in order to quantitatively expound the spatial pattern of the ecological risk based on ecosystem services, and identify ecological risk control priority regions at different confidence levels. The results showed that: (1) From 2000 to 2010, the average annual value of total terrestrial ecosystem services index in China was between 0-2.17, and slightly fluctuated between 0.30-0.57 over the years. Some 24.7% of the regions with significantly increasing value included Taiwan, Yunnan-Guizhou Plateau, inland Xinjiang of northwest China, 37.1% of the regions with significantly decreasing value, including northeast China, Qinghai-Tibet Plateau, central and eastern regions of China; (2) The risk losses of ecosystem services were exposed to different situations under different confidence levels. When the confidence level was 90%, the potential loss ratio of the total ecosystem services index was 24.19%, and the ecological risk index was 0.253. Furthermore, by analyzing the relationship between confidence level and ecological risk index, when the confidence level was high, the probability of risk was reduced correspondingly, but the losses correspondingly increased when risk occurred; (3) We investigated the scenario as an example under the 90% confidence level. The different eco-regions with the risk characteristics are as follows: the top six eco-regions with average ecosystem services risk index are Inner Mongolia Plateau, North China Plain, Loess Plateau, Northeast China Plain, Hengduan Mountain Region, and Qinghai-Tibet Plateau. The proportions of the eco-regions with extreme risk are 55.89%, 26.63%, 24.35%, 20.62%, 18.70% and 25.12%, respectively.