Floristic and functional affiliations of woody plants with climate in western Amazonia
Floristic and functional affiliations of woody plants with climate in western Amazonia
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DOI：
10.1111/j.1365-2699.2007.01878.x
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发表时间：
2008-05-01
影响因子：
3.9
通讯作者：
New, Mark
中科院分区：
文献类型：
--
作者：
Butt, Nathalie;Malhi, Yadvinder;New, Mark
目的研究亚马孙西部地区南北气候梯度上木本植物属相对丰度与降水状况之间是否存在直接关系。定位亚马逊西部的低地雨林。方法利用亚马逊西部39个0.1 ha样地的91个木本植物属的区系数据和0.5°全球降水数据，检验植物相对丰度（定义为每样地每个木本植物属在胸高处直径为2.5 cm的茎的百分比）与导出的旱季变量之间的相关性。然后根据先锋和耐阴生活史策略评估水分偏好。结果34%的属植物相对丰度分布与季节降水变量有显著相关。在干系和通才之间的大小级分布存在显著差异。在任何样地类型中，干类在任何大小类别中均不占主导地位，而气候通用型在干类和湿类中占主导地位。即使在干燥的森林中，干属也是少数。湿润属与耐阴性相关，而无降雨属往往是先驱者。主要结论水分季节性变化对群落组成的影响可能与绿荫耐受性和拓荒者排名之间的生活史权衡有关。潮湿森林多样性较高的一个可能原因是，高降雨量扩大了耐阴植物可用的生态位空间。确定哪些植物群受到哪些环境变量的限制，可以帮助我们了解森林组成现在如何变化，以及它在未来气候下如何变化：如果耐阴树木也不耐干旱，那么潮湿森林的群落结构可能更容易受到未来水分压力增加的影响。
Aim To test whether a direct relationship exists between the relative abundance of woody plant genera and precipitation regime along the north-south climate gradient of the western Amazon.Location Lowland rain forests in the western Amazon.Methods Floristic data on 91 woody plant genera, from 39 0.1-ha plots across the western Amazon, and precipitation data from a 0.5 degrees global data set were used to test for correlations between plant relative abundance (defined as percentage number of stems >= 2.5 cm diameter at breast height for each woody plant genus per plot) and derived dry-season variables. Moisture preference was then assessed in terms of pioneer and shade-tolerant life-history strategy.Results There were significant associations between the distribution of plant relative abundances and seasonal precipitation variables in 34% of genera analysed. Significant differences were identified in size-class distribution between dry affiliates and generalists. Dry affiliates were not dominant in any size class in any plot type, whereas climate generalists dominated most of the size classes in the dry plots and the mid-range size classes in the wet plots. Dry-affiliate genera were a minority, even in dry forests. Wet-affiliate genera were correlated with shade tolerance, whereas genera with no rainfall affiliation were often pioneers.Main conclusions The results suggest that moisture variable seasonality influences community composition in a manner that can be related to the life-history trade-off between shade tolerance and pioneer ranking. One possible reason for higher diversity in wetter forests is that high rainfall amplifies the niche space available to shade-tolerant plants. Determining which plant groups are constrained by which environmental variables can contribute to our understanding of how forest composition may be changing now, and how it may change under future climate: if shade-tolerant trees are also drought-intolerant, community structure in wet forests may be more vulnerable to future increases in moisture stress.