Pentaschistis (Poaceae) diversity in the Cape mediterranean region: habitat heterogeneity and climate stability
Pentaschistis (Poaceae) diversity in the Cape mediterranean region: habitat heterogeneity and climate stability
复制标题
地中海角地区五叶草属（禾本科）多样性：生境异质性和气候稳定性
DOI：
--
复制
发表时间：
2009
期刊：
影响因子：
--
通讯作者：
N. Zimmermann
中科院分区：
文献类型：
--
作者：
C. Galley;H. Linder;N. Zimmermann
目的评价生境异质性对南部非洲地中海地区巨型物种丰富的开普区物种丰富度和物种周转的影响。位于非洲南部的开普和德拉肯斯堡地区。方法利用生物气候资料估算Cape和Drakensberg地区的生境数量和生境异质性；然后利用这些数据来解释这两个地区五花科植物的物种多样性模式。生境变量被用来创建“生物气候单元”，以表征非洲南部的1 × 1细胞，并描述物种的生态位。利用这些生物气候单元，比较了两个地区物种的生态位和范围大小。系统谱被用来测试年龄和血统的影响。结果好望角地区五角星属植物的物种多样性和周转率高于德拉肯斯堡地区。两区生境数量和异质性均无显著差异。物种占据相同的估计生态位大小范围，但在好望角有更多的范围限制的Pentaschistis物种。主要结论：年龄和世系相关效应的作用被否定；生物多样性的差异存在于不同地区。目前的大型生境并不能解释这两个地区生物多样性的差异。在好望角有较多的范围限制物种不能用扩散机制或占用范围限制栖息地来解释。Pentaschistis和其他海角分支的物种与历史上气候稳定地区的物种具有相同的特征，古气候和古生物学证据表明，在整个更新世，海角气候比德拉肯斯堡气候更稳定。我们得出的结论是，相应的物种灭绝的缺乏可能使开普敦的物种积累成为可能。澳大利亚西南部植物区和地中海地区相似的气候和生物证据表明，相同的机制可能解释这些地中海地区的高物种丰富度。
Aim To evaluate the role of habitat heterogeneity on species richness and turnover in the mega species-rich Cape Floristic Region (Cape), the mediterranean region of southern Africa. Location The Cape and Drakensberg regions of southern Africa. Methods Bioclimatic data were used to estimate habitat amount and habitat heterogeneity in the Cape and Drakensberg regions; these data were then used to explain the patterns of species diversity in the Pentaschistis clade (Poaceae) in these two regions. Habitat variables were used to create ‘bioclimatic units’ to characterize 1 ′ × 1 ′ cells in southern Africa and to describe the niches of species. Using these bioclimatic units, the niche and range sizes of species in the two regions were compared. A phylogram was used to test for age and lineage effects. Results Pentaschistis species diversity and turnover are higher in the Cape than the Drakensberg. There is no significant difference in the habitat amount and heterogeneity between the two regions. Species occupy the same range of estimated niche sizes, yet there are significantly more range-restricted Pentaschistis species in the Cape. Main conclusions The roles of age- and lineage-related effects are rejected; biodiversity differences lie in the regions. Current macrohabitat does not explain the differences in biodiversity between the two regions. The larger number of range-restricted species in the Cape cannot be explained by dispersal mechanism or the occupation of range-restricted habitats. Species of Pentaschistis and other Cape clades share characteristics associated with species from historically climatically stable areas, and palaeoclimatic and palaeontological evidence indicates the Cape climate has been more stable than the Drakensberg climate throughout the Pleistocene. We conclude that the corresponding lack of extinction might have allowed an accumulation of species in the Cape. Similar climatic and biological evidence for the south-west Australian Floristic and Mediterranean regions indicate that the same mechanism might explain the high species richness of these mediterranean regions.