The environmental triangle of the Cerrado Domain: Ecological factors driving shifts in tree species composition between forests and savannas
The environmental triangle of the Cerrado Domain: Ecological factors driving shifts in tree species composition between forests and savannas
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DOI：
10.1111/1365-2745.12969
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发表时间：
2018-09-01
影响因子：
5.5
通讯作者：
de Oliveira-Filho, Ary Teixeira
中科院分区：
文献类型：
--
作者：
Bueno, Marcelo Leandro;Dexter, Kyle G.;de Oliveira-Filho, Ary Teixeira
1.巴西中部的塞拉多地区是新热带地区最大的热带稀树草原，尽管它被简单地描述为一个巨大的热带稀树草原，但它包含了相当大的植被异质性，人们对此知之甚少。我们的目的是确定如何在塞拉多植被类型在其树种组成的分歧和生态因素在驱动组成模式中发挥什么作用。我们使用了分布在塞拉多域的1，165个树种清单的数据集，这些树种来自六种具有大量乔木成分的植被类型：木本稀树草原，营养不良的cerradao，中营养cerradao，季节性干燥热带森林，半落叶林和万年青森林。我们发现了三个极端的树种组成，明确的潜在生态驱动因素，这使我们提出了一个三元模型，塞拉多植被三角，在塞拉多木本植被的特点。在一个极端，我们发现，半落叶林和万年青林是难以区分的植物区系，并发现在高水可用性的地区。在另一个极端是季节性干燥的热带森林，它们位于更肥沃的土壤上。在第三个极端，我们发现，所有类型的热带稀树草原，营养不良cerradao，是高度相似的树种组成，通常发现在土壤贫瘠和易燃性高的地区。中营养型塞拉岛的树种组成介于热带稀树草原和季节性干旱热带森林之间.由于气候变量导致的树种组成变化的缺乏表明，在均匀的大气候带内，由于当地基质异质性和火灾历史的复杂镶嵌，许多类型的森林和稀树草原共存。合成.我们的研究结果突出了塞拉多域森林-稀树草原过渡的复杂性，与了解塞拉多植被在环境变化下的未来有关。如果氮沉降是广泛的，一些稀树草原可能更有可能过渡到中营养cerradao，甚至季节性干燥的热带森林，而如果水的可用性增加，这些相同的稀树草原可能过渡到半落叶或万年青森林。我们的“塞拉多植被三角”模型提供了一个简单的概念工具，以框架的保护和管理的讨论。
1. The Cerrado Domain of central Brazil houses the largest extent of savanna in the Neotropics, but despite its simple characterization as a giant savanna, it contains considerable vegetation heterogeneity that is poorly understood.2. We aimed to determine how vegetation types in the Cerrado diverge in their tree species composition and what role ecological factors play in driving compositional patterns.3. We used a dataset of 1,165 tree species inventories spread across the Cerrado Domain, which come from six vegetation types that have a substantial arboreal component: woody savannas, dystrophic cerradao, mesotrophic cerradao, seasonally dry tropical forests, semideciduous forests and evergreen forests. We found three extremes in terms of tree species composition, with clear underlying ecological drivers, which leads us to propose a ternary model, the Cerrado Vegetation Triangle, to characterize woody vegetation in the Cerrado. At one extreme, we found that semideciduous and evergreen forests are indistinguishable floristically and are found in areas with high water availability. At another extreme lie seasonally dry tropical forests which are found on more fertile soils. At the third extreme, we found that all types of savanna, and dystrophic cerradao, are highly similar in tree species composition and are commonly found in areas of poor soils and high flammability. Mesotrophic cerradao is transitional in tree species composition between savannas and seasonally dry tropical forest.4. The lack of variation in tree species composition attributed to climatic variables indicates that within homogeneous macroclimatic zones, many types of forest and savanna co-exist due to complex mosaics of local substrate heterogeneity and fire history.5. Synthesis. Our findings highlight the complexity of forest-savanna transitions in the Cerrado Domain, with relevance for understanding the future of Cerrado vegetation under environmental change. If nitrogen deposition is extensive, some savannas may be more likely to transition to mesotrophic cerradao or even seasonally dry tropical forest, whereas if water availability increases these same savannas may transition to semideciduous or evergreen forest. Our "Cerrado Vegetation Triangle" model offers a simple conceptual tool to frame discussions of conservation and management.