Department of Plant Sciences, University of Cambridge Downing Street, Cambridge, CB23EA, U.K ; Department of Civil and Environmental Engineering, The Technion - Israel Institute of Technology Haifa, 32000, Israel.
Department of Biology and Environment, University of Haifa at Oranim Kiryat Tivon, 36006, Israel.
Ecol Evol. 2014 May;4(10):1963-71. doi: 10.1002/ece3.1072. Epub 2014 Apr 21.
Global patters of species distributions and their underlying mechanisms are a major question in ecology, and the need for multi-scale analyses has been recognized. Previous studies recognized climate, topography, habitat heterogeneity and disturbance as important variables affecting such patterns. Here we report on analyses of species composition - environment relationships among different taxonomic groups in two continents, and the components of such relationships, in the contiguous USA and Australia. We used partial Canonical Correspondence Analysis of occurrence records of mammals and breeding birds from the Global Biodiversity Information Facility, to quantify relationships between species composition and environmental variables in remote geographic regions at multiple spatial scales, with extents ranging from 10(5) to 10(7) km(2) and sampling grids from 10 to 10,000 km(2). We evaluated the concept that two elements contribute to the impact of environmental variables on composition: the strength of species' affinity to an environmental variable, and the amount of variance in the variable. To disentangle these two elements, we analyzed correlations between resulting trends and the amount of variance contained in different environmental variables to isolate the mechanisms behind the observed relationships. We found that climate and land use-land cover are responsible for most explained variance in species composition, regardless of scale, taxonomic group and geographic region. However, the amount of variance in species composition attributed to land use / land cover (LULC) was closely related to the amount of intrinsic variability in LULC in the USA, but not in Australia, while the effect of climate on species composition was negatively correlated to the variability found in the climatic variables. The low variance in climate, compared to LULC, suggests that species in both taxonomic groups have strong affinity to climate, thus it has a strong effect on species distribution and community composition, while the opposite is true for LULC.
全球物种分布格局及其潜在机制是生态学中的一个主要问题，多尺度分析的需求已得到认可。先前的研究认识到气候、地形、生境异质性和干扰是影响这些格局的重要变量。在这里，我们报告了对两个大陆不同分类群物种组成-环境关系及其组成部分的分析，这些关系在美国和澳大利亚的连续区域内进行。我们使用全球生物多样性信息设施的哺乳动物和繁殖鸟类出现记录的部分典范对应分析，来量化物种组成与不同空间尺度的环境变量之间的关系，范围从 10(5)到 10(7)km(2)，采样网格从 10 到 10000km(2)。我们评估了两个因素对环境变量对组成影响的概念：物种对环境变量的亲和力强度和变量的方差量。为了理清这两个因素，我们分析了得出的趋势与不同环境变量中包含的方差量之间的相关性，以分离观察到的关系背后的机制。我们发现，气候和土地利用/土地覆被是决定物种组成大部分可解释方差的原因，无论在规模、分类群和地理区域上都是如此。然而，物种组成归因于土地利用/土地覆被（LULC）的方差量与美国 LULC 内在变异性的方差量密切相关，但在澳大利亚则不然，而气候对物种组成的影响与气候变量中发现的变异性呈负相关。与 LULC 相比，气候的方差量较低，这表明两个分类群的物种对气候有强烈的亲和力，因此对物种分布和群落组成有强烈的影响，而 LULC 则相反。
