基于实践应用目的的城乡森林景观生物多样性指示因子研究

Biodiversity conservation is a key objective for forest landscape planning and management, but the multi-dimensional and multi-scale character of biodiversity renders full assessment difficult. Therefore, indicators are often used to monitor biodiversity, and important cost-benefit synergies can be achieved if indicators are derived from existing data. In this project, taking urban and rural forest landscape in Guanzhong region as study area, a model for classifying forest stand structures is developed based on four elements of forest landscape which can be found in existing database. The four elements include: tree canopy coverage, age of canopy trees, tree species composition and canopy stratification. Based on aerial photo interpretation and field survey, the model will then be tested as an indicator of overall plant species diversity and species composition by Generalized Linear Mixed Model and Multi-Response Permutation Procedures, respectively. It is expected that the complex biodiversity value can be substituted by visual, practical and scientifically tested structural forms of forest landscape, and understood without specialist taxonomic knowledge, making the model applicable in practice to support forest biodiversity conservation. Finally, the results of this project aim to provide theoretical basis and practical methods for biodiversity-oriented landscape planning and management. Meantime, the results will also contribute to existing database for the potential on biodiversity conservation.

生物多样性维护是当今城乡森林景观规划与管理的核心目标之一，但其自身多维度和多尺度的特性致使维护实践非常困难。因此，指示因子常被用来评估生物多样性。如果指示因子可从现有景观数据库中获取，往往还能达到省时省力的效果。本项目拟以陕西关中地区城乡森林景观为研究对象，使用现有数据库包含的森林景观的四要素（郁闭度、林龄、树种组成和垂直层级结构）作为指示因子，创建一套森林景观的结构模型。通过航片判读与实地调研采集数据，基于广义线性混合模型和多响应置换过程检验森林景观的结构类型与总体植物多样性和物种组成之间的关系。预期将复杂的生物多样性价值通过直观易懂、便于实践，并具有科学检验依据的森林景观的结构形式展现，不再受限于生物学分类知识，能够根据需求与目的切实地进行生物多样性维护。以期为今后我国以生物多样性为导向的城乡景观规划与管理提供理论依据和实践方法。同时，也为现有景观数据库赋予服务于生物多样性维护的潜力。

为探寻适合我国城乡生物多样性保护的有效措施和方法，本项目以关中地区陕西省二类森林资源清查固定样地为研究对象，通过航片判读与实地调研相结合的方法，构建了一套融入植被横向结构因子、乔木优势种的年龄因子、植被竖向结构因子和林木类型4个因子的生态单元分类系统，将研究区域样地内森林景观现状以空间结构形式展现。通过定量分析森林景观结构类型所蕴含的植物多样性价值梯度与物种组成的变化，检验了此森林景观结构模型在城乡生物多样性信息采集中的有效性，即不同结构的林地景观体现着不同等级的维管束植物多样性价值，包括α多样性和β多样性价值。研究结果表明此模型直观且可视化，能够根据需求与目的，设计不同生物多样性价值的森林景观，切实指导以生物多样性定向的城乡森林景观规划设计实践，对今后以生物多样性定向的城乡景观规划设计提供新的研究思路和实践指导。