琼北火山熔岩湿地生态安全格局研究

Research on ecological security pattern of volcanic Lava wetland in northern Hainan Province

火山熔岩湿地作为湿地系统中重要组成部分,广泛分布于海南岛北部火山岩地区,其生态安全状况直接影响着与其相连的水陆生态系统的安全。基于Landsat遥感影像、DEM数据以及植被覆盖指数,通过构建稳定性及敏感性评价体系,在景观斑块尺度上对海南岛北部火山熔岩湿地分布区1988—2018年的稳定性动态变化及敏感性现状进行分析,旨在探索该区域生态安全分布格局。结果表明:(1)1988和2018年两个时间节点的湿地斑块稳定性均以府城镇、城西镇、龙泉镇等熔岩湿地主要分布区域的稳定性最高,西南部农业用地区域及北部沿海地区斑块稳定性最弱;(2)1988—2018年期间研究区域熔岩湿地稳定性整体呈增长趋势,面积重心和稳定性重心在向南转移的同时在东西方向上呈收缩状态;(3)研究区域极度敏感和高度敏感区域主要分布在湿地密集分布区域,不敏感区域则主要分布在研究区域北部的海口市区及开发利用较多的沿海乡镇;(4)稳定性与敏感性结果呈正相关关系,湿地斑块稳定性低的沿海及城镇地区,在生态上多表现为不敏感和低敏感,而湿地斑块稳定性高的区域通常表现出高敏感性。这也说明自然生态系统相较人工生态系统,虽然其结构更为完善稳定,抗干扰能力相对较强,但也更容易遭到破坏,恢复周期长,因而在城镇发展等人为活动中需要慎重对待高敏感区域。

Lava wetlands are crucial components of the wetland ecosystem with wide distribution in the volcanic areas of northern Hainan Island. The ecological security of lava wetlands directly threatens the ecological security of the connecting hydro-land ecology systems. Based on the Landsat remote sensing images, DEM data, vegetation cover index,this study assessed the landscape patch-scale stability and sensitivity dynamic changes(1988—2018) of the lava wetlands in northern Hainan Island by constructing a stability-sensitivity evaluation system, aiming to explore the distribution patterns of ecological security in that region. The results showed that(1) in 1988 and 2018, the stability of wetland patches presented the highest in Fucheng Town, Chengxi Town, Longquan town and other main distribution areas of lava wetlands. On the contrary, the southwest agricultural area and the north coastal area showed the weakest.(2) During the period of 1988—2018, the stability of lava wetlands showed an overall increasing trend with its gravity center of area and stability shifting toward the south, together with a contraction in the east-west dimension.(3) The extremely-and highly sensitive areas in the study area were mainly distributed in the wetland densely distributed areas, whereas the non-sensitive areas were mainly distributed in the northern study area of Haikou City and the utilized coastal towns which were used more.(4) Stability was positively corelated with sensitivity. Specifically, wetland patches with low stability, such as the coastal and urban areas, were characterized by low ecological sensitivity and insensitivity, whereas wetland patches with high stability usually showed high sensitivity. The results suggested that although there were more stable structure and higher anti-interference ability in natural systems than that in artificial ecosystems, natural systems are more easily to be destructed with longer recovery cycle. Therefore, highly sensitive areas needed to be treated cautiously in urbanization practices as well as other anthropogenic disturbance.