Intermittent development of forest corridors in northeastern Brazil during the last deglaciation: Climatic and ecologic evidence
Intermittent development of forest corridors in northeastern Brazil during the last deglaciation: Climatic and ecologic evidence
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DOI：
10.1016/j.quascirev.2018.05.026
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发表时间：
2018-07
影响因子：
4
通讯作者：
I. Bouimetarhan;C. Chiessi;C. González‐Arango;L. Dupont;I. Voigt;M. Prange;K. Zonneveld
中科院分区：
文献类型：
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作者：
I. Bouimetarhan;C. Chiessi;C. González‐Arango;L. Dupont;I. Voigt;M. Prange;K. Zonneveld
巴西东北部的半干旱植被主要由Caatinga占主导地位，Caatinga是世界上最大和最丰富的干燥森林之一。卡廷加是一个具有战略意义的生物群落，因为它与塞拉多、大西洋森林和亚马逊接壤，在进化时期，它是这些地区之间生物交换的潜在走廊（或屏障）。因此，在这一地区过去的植被，生态和水文变化的准确重建是至关重要的了解生物群落边界的动态，可能发挥重要作用的扩散和多样化机制，更具体地说，长期的气候变化和热带生物多样性之间的联系。在这里，我们提出了高分辨率的孢粉学和元素数据从海洋核心GeoB 16205 -4检索的Parnaíba河口（巴西东北部）主要覆盖新仙女木（YD）。我们发现，YD间隔主要是湿在巴西东北部，但它是不均匀的，可以区分两个不同的阶段。一个显着的加强潮湿的条件之间的12.3和11.6卡尔凯尔BP记录的热带雨林和树蕨的扩张。这些结果与瞬态TraCE-21 k耦合气候模式模拟一致。我们推断，YD的第二个多雨阶段是由于在北大西洋的融水脉冲，这迫使向南移动的热带辐合带及其相关的降雨弱AMOC。我们的记录提供了新的证据，建立一个“东部森林走廊”，在现在的半干旱卡廷加允许过去的植物物种的生物交流。
The semi-arid northeastern (NE) Brazil vegetation is largely dominated by Caatinga, one of the largest and richest dry forests in the world. Caatinga is a strategic biome, since it has borders with Cerrado, Atlantic forests and the Amazon, acting as a potential corridor (or barrier) for biotic interchange between these regions during evolutionary times. Therefore, accurate reconstructions of past vegetation, ecological and hydrological changes in this area are critical to understanding the dynamics of biome boundaries that may play an important role in dispersal and diversification mechanisms and, more specifically, the link between the long-term climate variability and tropical biodiversity. Here, we present high-resolution palynological and elemental data from marine core GeoB16205-4 retrieved off the Parnaíba River mouth (NE Brazil) mainly covering the Younger Dryas (YD). We show that the YD interval was predominantly wet in NE Brazil, yet it was not homogenous and two distinct phases could be distinguished. A marked intensification of wet conditions between ∼12.3 and 11.6 cal kyr BP was recorded by the expansion of tropical rainforest and tree ferns. These results are in agreement with the transient TraCE-21k coupled climate model simulation. We infer that the second pluvial phase of the YD is related to a weak AMOC due to meltwater pulses in the North Atlantic, which forces a southward shift of the Intertropical Convergence Zone and its associated rainfall. Our records provide new evidence on the establishment of an “eastern forest corridor” in the nowadays semi-arid Caatinga allowing for past biotic interchanges of plant species.