气候和土地利用与空间结构在影响大熊猫同域分布大中型哺乳动物物种丰富度中的相对作用

气候因子和土地利用因子是影响生物多样性分布格局的两个主要驱动因素。然而，当前关于气候因子和土地利用因子对生物多样性影响的研究主要集中在物种层面上，在群落水平上对生物多样性的影响依然知之甚少。本研究以大熊猫同域分布大中型哺乳动物为研究对象，结合物种丰富度数据、气候数据、土地利用数据以及经纬度数据，构建基于不同变量组合的多元线性模型，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、土地利用因子和空间结构在影响大熊猫同域分布大中型哺乳动物物种丰富度中的相对作用。结果表明：（1）四川省大熊猫分布的五大山系内的大中型哺乳动物在属数和物种数方面差异较大。其中岷山山系的属数和物种数最高，分别为25属和28种，凉山山系的属数和物种数最低，分别为19属和20种，五大山系内排名前五的优势种分别为大熊猫、羚牛、野猪、中华斑羚、中华鬣羚；（2）大熊猫同域分布大中型哺乳动物物种丰富度在空间分布上差异较大。所有10 km×10 km栅格内的物种数在1~14之间，平均值为6.199±3.475；（3）完全模型（包含所有气候变量、土地利用变量和空间结构变量的模型，CLS）的拟合优度要好于其它6类模型，且包含土地利用变量模型的拟合优度要好于没有包含的模型；（4）气候变量、土地利用变量和空间结构变量共同解释了大熊猫同域分布大中型哺乳动物物种丰富度43.0%的空间变异，其中，土地利用变量对物种丰富度的解释率最高，单独解释率为23.2%，气候变量和空间结构变量的解释率则相对较低，单独解释率分别为6.3%和9.3%。这些研究结果说明土地利用因素是影响大熊猫同域分布大中型哺乳动物物种丰富度最为关键的驱动因素。因此，提高森林覆盖率，减少人为干扰和使用，是实现对大熊猫同域分布哺乳动物综合保护的关键。

The relative role of climate,land-use and spatial structure on spatial distribution pattern of species richness of large and medium mammals sympatric with giant pandas

Climate and land-use are recognized as the two main driving factors of biodiversity distribution patterns.However, most studies on the effects of climate and land-use have primarily focused on the species level, while their role on community diversity remains poorly understood.In this paper, combining species richness, climate and, land-use data as well as latitude and longitude data, we investigated the relative importance of climate, land-use, and spatial structure vari-ables on the species richness of large and medium mammals sympatric with giant pandas by using model comparison and variation partitioning.Our results show that(1) the number of genera and species of large and medium mammals differs in the five mountains of Sichuan Province.Minshan mountain has the highest number of genera(25) and species(28), while Liangshan mountain has the lowest number of genera(19) and species(20).The top five dominant species in the five mountains are the giant panda, takin, wild boar, Chinese goral, and Chinese serow.(2) We observed high spatial variation in species richness of large and medium mammals sympatric with giant pandas.The number of species in all 10×10 km grids ranged from 1 to 14, with an average of 6.199±3.475.(3) The full model(including all the climatic, land-use, and spatial structure variables, CLS) performed significantly better than all other six models, and the models including land-use covariates performed significantly better than those not including land-use covariates.(4) Climatic, land-use, and spatial structure variables together explained 43.0% of the variation in species richness, among which land-use variables accounted for the largest proportion, explaining 23.0% of the variation in species richness.Climatic and spatial variables explained only 6.3% and 9.3% of the variation in species richness, respectively.These findings indicated that the species richness of large and medium mammals sympatric with giant pandas was predominantly determined by land-use factors.Therefore, good forest stewardship to reduce anthropogenic threats and increase forest cover is the key to achieve comprehensive protection of large and medium mammals sympatric with giant pandas.