基于GAM模型的延河流域主要草地物种空间分布及其与环境的关系

Spatial distribution of major grassland species and its relations to environment in Yanhe River catchment based on generalized additive model.

对延河流域145个样地的主要草地物种空间分布和以GIS空间分析获取的该区12种主要环境因子之间的关系进行了定量研究,同时应用广义可加模型(GAM)分析了单物种的地理分布与环境梯度的关系。结果表明:影响延河流域典型草地物种百里香(Thymus mongolicus)空间分布的主要环境因子包括年均降雨、年均温度、蒸发量,其次是温度季节比,再次是坡位与坡度;主要草地物种与环境的关系非常密切,每个物种都存在自己特定的环境梯度空间中,并以不同的方式在空间上响应不同的环境因子;在流域尺度上利用GAM模型进行单物种和环境关系研究是可行的,能较好地描述物种空间分布和环境因子之间的关系。

A quantitative study on the relationships between the spatial distribution of major grassland species in 145 sampling plots in Yanhe River catchment and the 12 environmental factors extracted by GIS spatial analysis was conducted, and the geographic distribution of individual species with relations to environmental gradient was analyzed by using generalized additive model （GAM）. The results showed that the main environmental factors affecting the spatial distribution of the grassland species were mean annual precipitation, mean annual air temperature, and evaporation, followed by seasonal fluctuation of air temperature, and slope position and grade. There existed close relationships between the major grassland species and the environment, and each species had its own specific environmental gradient space, with different responses to the environment factors. GAM could better depict the relationships between species spatial distribution and environment factors, and it was feasible to employ this model to explore the relationships between single species distribution and environment in a catchment scale.