【作者】 刘强；

【导师】 吴志伟；

【作者基本信息】 江西师范大学 ， 自然地理学， 2022， 硕士

【摘要】 松材线虫病造成了区域生态与经济价值的重大损失,识别松材线虫病空间分布特征及潜在扩散路径对松材线虫病的防治具有重要的实际意义。本文以江西省南康区松材线虫病为研究对象,基于2020-2021年野外调查数据和地形、人类活动、植被等环境因子数据,采用空间点格局分析方法分析了南康区松材线虫病发生的空间分布模式及影响松材线虫病发生的显著因子;采用物种分布模型模拟了南康区松材线虫病的空间分布,并揭示了松材线虫病的空间分异特征;最后采用电路理论模型识别了松材线虫病的生境连通性,明确了潜在扩散路径与热点,并解释了环境因子对松材线虫病扩散的影响机制。主要研究结果如下:（1）南康区松材线虫病的发生不是随机分布的,而是存在着显著的空间聚集区。南康区南部是主要聚集中心,中、西、北部地区存在着多个次聚集中心。随着空间距离尺度增大,聚集特征越明显。（2）地形因子、植被因子和人类活动因子是影响病虫害空间异质性分布的主要因素。海拔、坡度、距道路距离、道路密度、距居民点距离、郁闭度和植被类型等环境因子对松材线虫病的发生具有重要影响。松材线虫病在距主干道路距离3500m以内附近是高发区。道路密度则增加了病虫害的发生强度。海拔200-300 m区域是松材线虫病的高发区（占全区面积30%）。松林中松材线虫病的发生概率显著高于其它植被类型。地形因子相比于人类活动因子更有线性趋势,波动更小影响更加稳定。（3）物种分布模型预测松材线虫病的性能表现良好。其中,随机森林模型综合评价精度最高。支持向量机、最大熵模型、增强回归树模型精度接近。模型预测显示松材线虫病潜在适生区分布广泛。龙回镇、十八塘镇、麻双乡、浮石镇等乡镇适宜生境面积大。（4）松材线虫病生境连通性存在空间差异性,在南康区呈条带状集中,南北狭长分布,形成高连通区域。南康区的朱坊乡、十八塘乡、横寨乡、横市镇、龙华乡、麻双乡、唐江镇等乡镇松材线虫生境连通性较好。环境因子对松材线虫病扩散具有重要作用,尤其在海拔200 m、临近松林、道路密度在0.30km·km^-2区域,松材线虫病的生境连通性较好扩散风险大。更多还原

【Abstract】 Pine wilt disease has caused great losses of regional ecological and economic value.Identifying the spatial distribution characteristics and potential diffusion path of pine wilt disease is of great practical significance for the prevention and control of pine wilt disease.Taking pine wilt disease in Nankang District of Jiangxi Province as the research object,based on the field survey data from 2020 to 2021 and the data of terrain,human activities,vegetation and other environmental factors,the spatial distribution mode of pine wilt disease and the significant factors affecting the occurrence of pine wilt disease in Nankang District were analyzed by using the method of spatial point pattern analysis;The spatial distribution of pine wilt disease in Nankang district was simulated by species distribution model,and the spatial differentiation characteristics of pine wilt disease were revealed;Finally,the circuit theory model was used to identify the habitat connectivity of pine wilt disease,clarify the potential diffusion paths and hot spots,and explain the influence mechanism of environmental factors on the diffusion of pine wilt disease.The main results are as follows:（1）The occurrence of pine wilt disease in Nankang district is not randomly distributed,but there are significant spatial aggregation areas.The south of Nankang district is the main gathering center,and there are many sub gathering centers in the central,Western and northern regions.With the increase of spatial distance scale,the aggregation characteristics become more obvious.（2）Terrain factor,vegetation factor and human activity factor are the main factors affecting the spatial heterogeneity distribution of diseases and pests.Environmental factors such as altitude,slope,distance to nearest roads,road density,distance to nearest settlement,canopy density and vegetation type have important effects on the occurrence of pine wilt disease.Pine wilt disease is a high incidence area within 3500 m from the main road.Road density increases the occurrence intensity of diseases and pests.The area with an altitude of 200-300 m is a high incidence area of pine wilt disease（accounting for 30%of the whole area）.The occurrence probability of pine wilt disease in pine forest is significantly higher than that of other vegetation types.Compared with human activity factors,terrain factors have more linear trend,less fluctuation and more stable impact..（3）The performance of species distribution model in predicting pine wilt disease is good.Among them,the comprehensive evaluation accuracy of random forest model is the highest.The accuracy of support vector machine,maximum entropy model and enhanced regression tree model is close to each other.The model prediction shows that the potential suitable areas for pine wilt disease are widely distributed.The suitable habitat area in Longhui Town,shibatang Town,Mashuang Township,Fushi town and other towns is large.（4）There are spatial differences in habitat connectivity of pine wilt disease,which is concentrated in strips in Nankang district and distributed in narrow and long areas from north to south,forming a high connectivity area.The habitat connectivity of pine wilt disease in Zhufang Township,shibatang Township,hengzhai Township,Hengshi Town,Longhua Township,Mashuang Township and Tangjiang town in Nankang district is good.Environmental factors play an important role in the spread of pine wilt disease,especially at an altitude of 200m,near pine forest and road density of0.30km·km^-2 area,the habitat connectivity of pine wilt disease is good,and the risk of diffusion is high.更多还原