1980—2015年京津冀地区雁鸭类潜在栖息地连接度变化及驱动因素

Changes and Driving Forces of Anatidae's Potential Habitat Connectivity in Beijing-Tianjin-Hebei Region from 1980 to 2015

近几十年来,京津冀地区湿地面积萎缩,生态功能下降,严重影响了湿地水鸟的栖息地质量及栖息地间的连接,对水鸟类的迁徙、繁殖产生较大干扰,为了从整体上定量分析近几十年来湿地栖息地质量及连接度的变化,采用MaxEnt模型(maximum entropy model,最大熵模型),基于京津冀地区雁鸭类的出现点和环境因子反演其潜在栖息地,并根据图论法原理,利用ECA指数(equivalent connected area,等效连接指数),度量1980—2015年潜在栖息地连接度的变化.结果表明:①1980—2015年京津冀雁鸭类潜在栖息地面积总体呈下降趋势,由1980年的6 898 km^2减至2015年的3 764 km^2,减少了45. 0%,其中,低适宜区面积降幅最为明显,为50. 5%; 2009—2015年高适宜区有增加趋势.②1980—2015年雁鸭类潜在栖息地连接度呈持续下降趋势,2000年以后的连接度下降速率大于2000年以前;潜在栖息地连接结构的空间分布有向环渤海地区转移的趋势,连接结构变化最为明显的区域为京津冀中部平原地区.研究显示,区域气候趋暖变干、水资源的供需失衡、水利工程设施建设以及人口增加与经济发展带来的土地利用变化是潜在栖息地面积与连接度下降的主要影响因子,而近些年保护区的建立及生态补水措施等生态保护政策对高适宜区的退化有一定缓解作用.

In recent decades,the shrink of wetland and the decrease of its ecological function in the Beijing-Tianjin-Hebei Region have seriously affected the quality and connectivity of wetland bird habitat,which has severely disrupted the migration and breeding of birds in the wetlands. To quantitatively analyze changes in the quality and connectivity of wetland habitats in recent decades,potential habitat patches were identified using the maximum entropy( MaxEnt) model based on the occurrence and environmental factors of Anatidae in the Beijing-Tianjin-Hebei Region. Next,habitat connectivity analysis was carried out using the equivalent connectivity area( ECA) index based on graph theory from 1980 to 2015. The results show that:( 1) The potential habitat area of Anatidae in the Beijing-Tianjin-Hebei Region presents a downward trend in the past 35 years,decreasing from 6898 km^2 in 1980 to 3764 km^2 in 2015( a decrease of 45. 0%).The decline in marginally habitat is most obvious( a decrease of 50. 5%). Highly suitable habitat area presents an upward trend between2009 and 2015.( 2) Connectivity of potential habitats has been decreasing over the past 35 years. Furthermore,the decline rate of connectivity of potential habitat after 2000 was greater than before. On the other hand,the spatial distribution of the potential habitat connecting structure has shifted to the Bohai Rim. The most obvious change in the connection structure is in the central plain of BeijingTianjin-Hebei Region. The main factors driving the decline of the area and connectivity of potential habitats include the reduction of precipitation,the strengthening of evaporation,the imbalance between water supply and demand,the construction of hydraulic engineering facilities and the change of land use resulted from population growth and economic development. On the contrary,the Ecological protection policies such as the establishment of ecological reserve and water supplement will alleviate the degradation of highly suitable potential habitat.