气候变化对长江口和黄河口渔业生态系统健康的潜在影响

Projecting Fishery Ecosystem Health Under Climate Change Scenarios: Yangtze River Estuary and Yellow River Estuary

关键词:  长江口  黄河口  生态系统健康  气候变化情景

Key words:  Yangtze River estuary  Yellow River estuary  Ecosystem health  Climate change scenarios

摘要:

本研究采用层次灰色综合评价模型，结合动态生物气候分室模型预估的长江口和黄河口鱼类资源密度增量分布结果，对不同气候变化情景(RCP2.6、RCP6.0和RCP8.5)对长江口和黄河口渔业生态系统健康的潜在影响进行了分析。从生态环境、生物群落结构和生态系统功能三个层面构建了长江口和黄河口渔业生态系统健康评价体系。2015–2050年，长江口和黄河口渔业生态系统健康水平随着温室气体排放程度的增加而降低，即RCP2.6情景下健康水平最高，RCP6.0情景次之，RCP8.5情景最低。两个河口的健康水平随时间推移在RCP2.6情景下呈现出“高–低–高”的变化趋势；在RCP6.0情景下呈现出“低–高–低”的变化趋势；在RCP8.5情景下两个河口略有差异，黄河口呈“高–低–高”的变化趋势，长江口呈“低–高–低”的变化趋势。若以2050年渔业生态系统健康水平作为“最终状态”，两个河口RCP2.6情景下的健康水平高于RCP6.0和RCP8.5情景：长江口RCP2.6情景下的健康评价值为0.61，是RCP6.0和RCP8.5情景下健康评价值的1.9倍和1.8倍；黄河口RCP2.6情景下的健康评价值分别是RCP6.0和RCP8.5情景的2.8倍和2.2倍。

Abstract:

Estuaries are the unique ecosystem with variable environment and higher diet foundation, are the spawning grounds, feeding grounds and nursery grounds of many fishery species, which greatly contribute to the fisheries yields. So, estuary ecosystem health is critical to the sustainable recruitment of fishery species. In the present study, based on the projections of fish abundance increment distribution under three climate change scenarios (RCP2.6, RCP6.0 and RCP8.5) in the Yangtze River estuary and Yellow River estuary by the dynamic bioclimate envelope mode, the fishery ecosystem health in Yangtze River estuary and Yellow River estuary was evaluated by hierarchical grey comprehensive evaluation model. The health evaluation system in Yangtze River estuary and Yellow River estuary included environment, fishery community structure and ecosystem function and service. During 2015–2050, the highest health index was found in RCP2.6 scenario both in Yangtze River estuary and Yellow River estuary, and then was RCP6.0 scenario, the lowest health index was found in RCP8.5 scenario. The health level gradually decreased with the increase of greenhouse gas emission levels. The health index showed the “high-low-high” trend with time under RCP2.6 scenario both in Yangtze River estuary and Yellow River estuary; however, it was “low-high-low” trend under RCP6.0 scenario. Under RCP8.5 scenario, the amplitude of health index fluctuation was lower than those under the other scenarios, and there were some differences between two estuaries, the health indices showed a “low-high-low” changing trend in Yangtze River estuary, meanwhile, the health indices firstly increased, then decreased, finally showed a slight increase in Yellow River estuary. If the health index in 2050 was regarded as the final results, the health levels under RCP2.6 scenario were higher than those under the other scenarios in two estuaries. The health index under RCP2.6 scenario was 0.61 in Yangtze River estuary, and it was 1.9 times and 1.8 times for RCP6.0 and RCP8.5 scenarios, respectively. The health index under RCP2.6 scenario was 2.8 times and 2.2 times for RCP6.0 and RCP8.5 scenarios in Yellow River estuary, respectively.