互花米草入侵对霞浦滨海湿地景观的影响

摘要

以霞浦滨海湿地2006、2011和2016年三期多源高分辨率卫星影像为基础数据,在地理信息系统的平台上,运用景观转移矩阵、景观质心转移和景观格局指数的方法,并结合Pearson相关分析,探究互花米草入侵对霞浦滨海湿地景观格局演变的影响.结果表明:2006—2016年,霞浦滨海湿地中自然湿地和人工湿地面积总体减少,非湿地景观面积总体增加,其中互花米草滩面积从2006年的1 147.64 hm2到2016年的3 334.67 hm2,增加了2 187.03 hm2.从景观转移矩阵可以看出,其他景观类型转入互花米草面积比转出面积更明显,转入和转出的景观类型主要是湿地景观中潮间裸滩、养殖场、农田,说明这些景观类型空间格局受到互花米草入侵影响较大.互花米草转入和转出的斑块整体呈现破碎化特点,扩散的范围广.通过景观质心变化方法可以发现,2006—2011年,互花米草景观质心向东偏北方向移动了3.32 km;2011—2016年,质心向西北方向移动了14.44 km.相关分析表明:互花米草滩的形状指数(LSI)与景观水平格局指数呈现显著的相关关系,其中:与景观形状指数(LSI)(1.000**,P＜0.01)呈现极其显著的正相关,与聚集度(AI)和相似毗邻百分比(PLADJ)呈现显著的负相关(P＜0.05),说明互花米草的斑块形状变化会影响区域景观形状特征、聚集度变化.互花米草空间分布、扩张特征以及格局变化对滨海湿地景观产生重要的影响,改变区域景观结构的组成、多样性和异质性特征.%Based on the multi-source high-resolution satellite imagery of coastal wetlands in 2006,2011 and 2016 in Xiapu County,using landscape transformation matrixand pattern indexes and center of mass transfer methods in the platform of GIS,the invasion impact of Spartina alterniflora on the landscape pattern of coastal wetland in Xiapu County were analyzed combining with Pearson correlation analysis.The results showed as follows: from 2006 to 2016,the area of natural and constructed wetlands generally decreased,and the area of non-wetland landscapes generally increased.The area of S.alterniflora expanded from 1 147.64 hm2in 2006 to 3 334.67 hm2in 2016,a total increase of 2 187.03 hm2.The landscape transfer matrix suggested that the area of S.alterniflora transferred to other landscape types was more obvious than S.alterniflora converting to other landscape types,and the types of landscapes shifting in and out are mainly intertidal beach,farm and farmland in the wetland landscape showing that the spatial pattern of these landscape types was heavily influenced by the invasion of S.alterniflora.The plaque change showed the overall fragmentation characteristics and proliferation of a wide range.Through the method of change of landscape centroids,from 2006 to 2011,the centroid of the S.alterniflora landscape moved 3.32 km eastward;from 2011 to 2016,the centroid moved to the northwest by 14.44 km.The correlation analysis indicated that LSI of S.alterniflora had a significant correlation with the landscape pattern index,and LSI(1.000**,P＜0.01)showed extremely significant positive correlation,and there was a significant negative correlation between AI and PLADJ(P＜0.05),indicating that the shape change of the landscape shape and the degree of aggregation were caused by the change of the patch shape of S.alterniflora.The results concluded that the spatial distribution,dilatation characteristics and pattern change have important impact on the coastal wetland landscape,and change the composition,diversity and heterogeneity of the regional landscape structure.