基于景观格局和连接度评价的生态网络方法优化与应用

Improvement and application for ecological networks using landscape pattern and connectivity methods

景观生态学中常凭借最小累积阻力模型构建目标种生态网络,以提升破碎栖息地间的景观连接度,缓解生境破碎化负面影响.但传统最小累积阻力生态网络方法缺乏对生态网络的效用验证,对研究地的景观结构变化与生态过程的影响认识不足.本研究运用景观格局指数与连接度概率指数,定量评价生态网络构建前后的研究地景观结构与连接度特征,并以崇左白头叶猴栖息地生态网络为例,详尽叙述此生态网络方法的优化与应用过程.通过对白头叶猴栖息地斑块进行辨认、踏脚石斑块识别,对研究地用地类型进行划分并进行阻力赋值,运用最小累积阻力模型生成了20条白头叶猴栖息地生态网络廊道;然后利用景观结构指数与连接度概率指数结合的方法,对生成的生态网络结构和功能连接度进行评价.结果表明:凭借最小累积阻力模型构建的目标种生态网络,能有效提升栖息地生境的完整性和连续性,降低总体破碎化水平,并改善生境质量.同时,该生态网络构建能提升生境景观的结构连接度与功能连接度,且两方面的连接度变化在结果上具有极显著的一致性(R^2=98.3%,P<0.01).生态网络带来的景观结构方面变化与功能连接度的关联性不强,两种指数间的相互关系不如结构与功能的内在关系显著.

In landscape ecology,the target species ecological network is often constructed by the least-cost path model(hereafter LCPM)to improve landscape connectivity among discrete habitats and to mitigate the negative impacts of habitat fragmentation.Nevertheless,the traditional ecological network method based on LCRM has insufficient understanding of landscape structure changes and ecological processes of research site.We used landscape pattern index and connectivity probability index to quantitatively evaluate the landscape structure and connectivity characteristics of the research area before and after the construction of the ecological network.The ecological network of the habitat of Presbytis leucocephalus,located in Chongzuo,Guangxi Province,was used as an example to describe the optimization and application of this method in detail.We identified the habitat and stepping stone patches of the target species,classified land use types of the study area,set up different resistant values,and obtained 20 corridors of ecological network using LCPM.The results showed that LCRM could effectively improve habitat integrity and continuity,reduce overall fragmentation level,and improve habitat quality based on the structural and functional connectivity evaluation by landscape pattern index and connectivity probability index.Meanwhile,its construction could improve the structural connectivity and functional connectivity of the habitat landscape,with significant consistency of the connection degree changes in both aspects(R^2=98.3%,P<0.01).However,the relationship between landscape structure changes and functional connectivity caused by the network was not strong,and their relationship was not as significant as the inherent relationship between the structure and function.