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中国山茶科植物物种丰富度的主要影响因素

The main factors affecting the species richness of Theaceae in China

  • 摘要: 生物多样性空间分布格局及其与环境因子之间的关系一直是生态学、保护生物学和生物地理学研究的核心问题。尽管气候、地形和人类活动等因子是影响生物多样性空间分布格局的重要因素,但关于它们在影响生物多样性空间分布格局中的相对作用依然知之甚少。为此,以中国山茶科植物为研究对象,结合物种丰富度数据、气候数据、地形数据以及人类活动数据,构建基于不同变量组合的负二项广义线性模型,并通过模型拟合优度比较和方差分解等方法,探讨气候因子、地形因子和人类活动因子在影响中国山茶科植物物种丰富度中的相对作用。结果表明:(1)中国山茶科植物物种丰富度在空间分布上差异较大,所有50 km×50 km栅格内的物种数在1~88之间,平均值为14.425±13.756;(2)包含所有气候变量、地形变量和人类活动变量的模型的拟合优度要好于其它模型;(3)在最优模型中,物种丰富度与年平均温度呈显著正相关关系(P < 0.001),与等温性(P < 0.05)、降水季节性(P < 0.001)和农田比例(P < 0.01)呈显著负相关关系,与气温年较差(P < 0.01)、年降水量(P < 0.001)和海拔极差(P < 0.001)呈显著凸形关系;(4)气候因子、地形因子和人类活动因子在影响中国山茶科植物物种丰富度中的相对贡献率分别为67.86%、21.50%和10.64%。这些研究结果说明气候因子在影响中国山茶科植物物种丰富度中起决定性作用。因此,实施合理有效的保护和管理策略,以减缓气候变化和人类活动的负面影响,是实现对中国山茶科植物科学保护的关键。

     

    Abstract: Spatial distribution patterns of species diversity and its relationship with environmental factors have been one of core issues in ecology, conservation biology and biogeography. Although climate, topography and human activity factors have been considered as key factors in determining the spatial distribution patterns of species diversity, little is known about their relative roles in affecting the spatial distribution pattern of biodiversity. In this study, combined with the species richness data, climatic data, topographic data as well as human activity data, we investigated the relative importance of climatic variables, topographic variables and human activity variables on the richness of Chinese Theaceae species by using model comparison and variation partitioning. The results showed that: (1) We observed high spatial variation in richness of Chinese Theaceae species. The number of species in all 50×50 km grids ranged from 1 to 88, with an average value of 14.425±13.755; (2) The model including all the climatic, topographic and human activity variables performed significantly better than all other models; (3) In the optimal model, species richness was significantly positively correlated with annual mean temperature (P < 0.001), significantly negatively correlated with isothermality (P < 0.05), precipitation seasonality (P < 0.001), and proportion of cropland (P < 0.01), and significantly convexly correlated with temperature annual range (P < 0.01), annual precipitation (P < 0.001), and elevation range (P < 0.001); (4) Climatic variables, topographic variables and human activity variables explained 67.86%, 21.50% and 10.64% of variation in species richness, respectively, which indicated that the richness of Chinese Theaceae species was predominantly determined by climatic factors. Therefore, implementing effective protection and management strategies to mitigate the negative effects of climate change and human activities is the key to realize the scientific protection of Chinese Theaceae species.

     

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