基于GIS的松树萎蔫病发生格局研究

Study of the pine wilt disease occurrence and its range expansion pattern based on GIS

通过GIS对发病信息的空间定位以及发病林型几何质心的挖掘，对空间点（单元）发病属性数据建立距离矩阵，利用空间自相关性指数Moran’s I研究探询安徽滁州地区松树萎蔫病发生的空间扩散机制，结果表明：松树萎蔫病在安徽滁州和马鞍山地区的发病率从0．18％到46％不等，严重发病的区域主要集中在明光县管店林业总厂及其相邻的鲁山林厂和老嘉山林场，发病率都在40％～46％；其次为马鞍山地区的横山林场及其附近的薛津镇．在安徽滁州地区和马鞍山地区松树萎蔫病的发生和扩散有适宜的生境条件，该地区松材线虫易感植被集聚分布的特点使松树萎蔫病持续发生和蔓延成为可能．空间自相关性的分析发现，松树萎蔫病在该区域内发病的Moran’s I的空间自相关指数高达74.86％（0．05水平检验），推断在安徽滁州和马鞍山地区1316个以林型为发病单元的发病点的分布格局为高度聚集型，同时也说明松树萎蔫病在安徽滁州和马鞍山地区的发生具有一定强度的传染性．

Through exploring the spatially referenced pine wilt disease （PWD） occurrence data and mining the centroid of its infested forest stand, distance matrix of the geo-coded PWD infested rate was derived, and the spatial statistic autocorrelation index Moran＇ s I was used in exploring PWD spatial expansion mechanism. Results show that PWD occurrence rate in Chu-Zhou and Ma An-Shan region varied from 0. 18% to 46%. Most severe infested region centered around Guandian national owned woodland and its neighboring Lu shan and Lao-jia shan national woodland, corresponding infested rate varied from 40% to 46%. The second rank infested region centered around Heng-shan woodland and Xuejing country in Ma An Shan region. The existence of the suitable habitats of the cluster-distributed susceptible plants makes the consecutive PWD occurrence possible. Based on the ArcView spatial model, 1316 point investigated data on the occurrence of PWD in the given region were analyzed. A significant autocorrelation on the occurrence of PWD were derived. The Moran＇s I spatial autocorrelation index was 0. 7486. Standardized Z score for Moran＇s I spatial statistic test was larger than the un-significant threshold 1.96. A clustered range expansion pattern for the pine wilt disease trend could be concluded in the 95% confidence interval, and also indicate that PWD have certain infectivity in this region.