基于区域物种库的植被结构模拟研究－以黄土高原为例

Due to long history of war, unreasonable land use and farming practices in Loess Plateau, such as over-cultivation, grazing and deforestation, they have caused serious degradation of vegetation in this region, which severely restrict sustainable development of the region's economic and society. However, there is not sufficient scientific consensus and uniform understanding on how to restore the degradation vegetation and what vegetation structure should be reconstructed in the region. This project tries to answer the above two questions from regional species pools perspective in Loess Plateau. Through the construction of species and environmental databases of Loess Plateau, species distribution models and model fusion technology are used to predict species potential distribution area, and then species assembly rules are developed to modeling vegetation structure at regional scale in Loess Plateau. Cluster analysis and general dissimilarity model in community ecology are used to divide predicted vegetation structure database into regional vegetation types. Ordination technologies are used to investigate the relationship between vegetation types and environment change in Loess Plateau. The main research objectives of this project are to dig potential vegetation structure and species composition information at regional scale and explore mechanism of vegetation structure to environment change in Loess Plateau. The project not only provides scientific base for species selection strategy and vegetation structure reference standard of revegetation in Loess Plateau, but also supplies new theory and method for comprehensively managing vegetation resources and making effectively use of vegetation function of Loess Plateau.

黄土高原地区由于长期历史战乱，过度开垦、放牧与砍伐等不合理的土地利用和耕作方式，引起黄土高原植被的急剧退化，严重的制约着该地区经济和社会的可持续性发展。然而恢复该地区植被的标准及植被结构的重建策略到目前为止尚未取得充足且统一的认识。本项目拟从黄土高原区域物种库的角度，通过构建黄土高原地区物种库和环境数据库，利用物种分布模型与模型融合技术预测物种的潜在分布区，采用合适的物种聚合规则模拟黄土高原区域植被结构；再使用群落生态学中的多元分析手段划分黄土高原区域植被类型，同时探讨植被结构与环境变化的关系。本项目旨在详细阐述黄土高原区域植被结构与物种组成的潜在信息及其对环境变化的响应机制。本项目不仅能够为黄土高原植被恢复中物种的选择策略和植被结构重建的参考标准提供基础数据和科学依据，而且能够为今后更进一步的全面的管理黄土高原区域植被资源并高效的发挥植被水土保持功能提供新的理论和研究方法。

黄土高原地区长期受到人类活动的干扰和破坏，自然植被已经失去了原来的面貌，植被急剧退化，使得当地的水土流失严重。因此，从区域尺度上全面了解并深度挖掘植被结构与物种组成的潜在信息并构建区域植被结构数据库是黄土高原植被重建顺利进行的必要条件。本项目通过广泛搜集黄土高原地区植物名录及其标本数据建立了黄土高原区域物种库的地理分布数据库；整合世界的气候系统（Bioclim系统、Holdridge生命地带系统、Kira指标系统）建立了刻画物种气候生态位的13个气候指标系统；利用物种分布模型连接植物标本数据和13个气候指标系统，建立了模拟和预测物种的潜在分布区、重要气候因子、气候阈值、气候响应曲线及其生境适宜性的工作流，针对于重要的水土保持植物，如沙棘、刺柏、油松、刺槐等多目标利用生态和经济价值的物种分别研究了它们的种植区划、世界引种推广、优先造林区域等；建立了基于Holdridge模型划分黄土高原植被功能单元的工作流，并评估了各个植被功能单元对气候变化的敏感性。将模拟物种分布区和生境适宜性的工作流与植被功能单元制图的工作流结合将能够帮助我们深度挖掘黄土高原植被结构与物种组成的潜在信息。