东圳水库流域的景观连通度分析

景观连通度是指景观有利于或者妨碍生物在资源斑块间运动的程度。景观连通度缺乏和栖息地斑块隔离会干扰授粉、种子传播、基因流、野生动物迁移和繁殖及其他生态过程,因此景观连通度研究是现代生物多样性保护策略研究的关键技术,开展此类研究对于区域生物多样性保护和生态平衡维持具有重要意义。本研究利用2001、2006、2010年东圳水库流域的遥感影像,通过分析其土地覆盖变化,研究人类土地利用逐步增强的流域长期景观连通度动态变化趋势。研究结果表明:在不同年份中,设置物种的迁移距离阈值和在迁移距离内到达目标斑块的概率均一致时,该流域景观连通度从2001—2010年有递减的趋势,表明了斑块破碎化加大,景观连接度逐年递减;随着距离阈值增大,物种的迁移距离越大,斑块之间的连接越好,景观连接度增大,对景观连通度产生影响的重要斑块数量减少。从不同年份中提取的重要斑块的土地覆盖类型来看,林地、果园、耕地、水体都对景观连通度产生较大影响,对景观产生重要作用的斑块的面积占总景观面积的比例逐年递减,而建设用地和裸地对景观连通度的贡献均很少。研究认为,应保持流域景观的高连通度,进而确保区域各种物种传播和基因流动,以减缓生物多样性的下降。

An Analysis of Landscape Connectivity in Dongzhen Reservoir Watershed

Landscape connectivity is the degree by which a landscape facilitates or impedes biological movements among patches .The damage of landscape connectivity , with subsequent isolation of habi-tat patches, can obstruct pollination , seed dispersal , gene flow, wildlife migration and breeding and other ecological processes .So enhancing landscape connectivity is important in regional biodiversity protection and eco-balance .This study used remote images to analyze land use and cover change and applied the results to investigating landscape connectivity in Dongzhen Reservoir Watershed . When distance threshold and probability to target patches was set , it was found that the connectivity de-creased from 2001 to 2010, companied with the increasing of fragmentation .With the increasing of distance threshold and dispersal distance of species , links among habitat patches became better and the connectivity increased , but the number of critical patches affecting the connectivity would de-crease.In a certain distance threshold range , with the increasing of distance threshold , most patches＆amp;nbsp;would greatly affect the connectivity .In particular , we found that forests , orchards , cultivated lands and water body had a significant impact on the connectivity .Construction lands and bare lands con-tributed little to the connectivity in 2001, 2006 and 2010.The ratio of total critical patches area in the watershed decreased from 2001 to 2010 .