Environmental and spatial controls of palm (Arecaceae) species richness across the Americas
Environmental and spatial controls of palm (Arecaceae) species richness across the Americas
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DOI：
10.1111/j.1466-822x.2005.00167.x
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发表时间：
2005-09-01
影响因子：
6.4
通讯作者：
Balslev, H
中科院分区：
文献类型：
--
作者：
Bjorholm, S;Svenning, JC;Balslev, H
目的确定控制美洲棕榈树物种丰富度分布的主要因素，了解气候和其他环境因素相对于空间变量(作为历史等非环境因素的替代)的相对重要性，并评估所发现的格局对空间尺度变化的稳健性。热带和亚热带美洲(北纬34度-S 34度；西经33度-120度)。我们使用多元回归和变异划分来检验物种丰富度与5个环境参数[年平均温度(摄氏度)、年平均降水量(mm年(-1))、年潮湿日数(-1)、地形范围(最大-最小海拔)、植被类型数]和9个空间变量(三次趋势面多项式)之间的关系。结果在热带地区，棕榈树物种丰富度在南部、乔科地区、亚马孙盆地西部和东部、安第斯山脉东坡出现峰值，纬度丰富度梯度也很强。通过分析所有空间尺度，纯环境变化分量和纯空间变化分量具有相同的大小。与水有关的变量，如年降雨量和雨天数是主要的丰富度预测因子。空间变量，特别是纬度平方也是重要的，而与温度和生境相关的变量相对不重要。我们的主要结论表明，在美洲，从1度到10度的空间尺度上的棕榈树物种丰富度最大程度地受水分供应的控制，尽管未知的大尺度因素，可能是土壤、历史过程或几何限制，也是重要的。
Aim To determine the main factors that control the distribution of palm species richness across the Americas, to understand the relative importance of climatic and other environmental factors vs. spatial variables (as substitutes for non-environmental factors such as history), and to evaluate how robust the patterns found are to changes in spatial scale.Location Tropical and subtropical America (34 degrees N-34 degrees S; 33 degrees W-120 degrees W).Methods We provide a GIS-based analysis of spatial variation in species richness at 10 grain sizes (1 degrees-10 degrees square grid cells). We use multiple regressions and variation partitioning to test patterns of species richness in relation to five environmental descriptors [mean annual temperature (degrees C), mean annual precipitation (mm year(-1)), number of wet days year(-1), topographical range (maximum-minimum elevation), number of vegetation types] and nine spatial variables (the terms of a cubic trend-surface polynomial).Results We observe peaks in palm species richness in southern Mesoamerica, the Choco area, western and eastern Amazon basin, and east Andean slopes, and a strong latitudinal richness gradient even within the tropical zone. Pure environmental and pure spatial variation components are of equal magnitude through all spatial scales analysed. Water-related variables such as annual rainfall and number of wet days are the main richness predictors. Spatial variables, notably latitude squared are also important, whereas temperature- and habitat-related variables are relatively unimportant.Main conclusions Our analysis suggests that in the Americas, palm species richness at spatial scales from 1 degrees to 10 degrees is most strongly controlled by water availability, although unknown broad-scale factors, perhaps soil, historical processes or geometric constraints, are also important.