Holocene dynamics of vegetation change in southern and southeastern Brazil is consistent with climate forcing
Holocene dynamics of vegetation change in southern and southeastern Brazil is consistent with climate forcing
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DOI：
10.1016/j.quascirev.2016.06.011
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发表时间：
2016-08
影响因子：
4
通讯作者：
J. Rodrigues;H. Behling;T. Giesecke
中科院分区：
文献类型：
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作者：
J. Rodrigues;H. Behling;T. Giesecke
在北纬中高纬度地区，冰川后植被的变化往往是同步发生的，主要是由气候突变引起的大面积植被变化。基于巴西南部和东南部的19个花粉图，我们探讨了低纬度地区的植被变化是否也具有类似的同向性。我们利用序列分裂技术检测花粉图中过去植被的变化，并计算主曲线和变化率，直观地评价花粉图的组成和动态变化。结果表明，植被变化主要发生在全新世下半叶，变化周期明显。植被变化的特征总体上与向湿润条件的转变相一致，并与推断的南美季风的转变相一致。来自Cariaco盆地的洞穴化石和钛元素记录表明，在这里探测到的植被变化时期（8900、5900、2800、1200和550 cal - years BP）的年代不确定性范围内，降水制度发生了几次快速变化。研究结果表明，低纬度地区植被组成受水文岁差强迫的影响，而高纬度和中纬度地区的变化往往由快速气候变化触发和同步。花粉图记录了全新世期间单个分类群丰度的变化和林地覆盖量的变化，而微小的成分变化表明植被类型的区域稳定性。
At mid to high northern latitudes postglacial vegetation change has often occurred synchronously over large regions triggered mainly by abrupt climate change. Based on 19 pollen diagrams from southern and southeastern Brazil we explore if similar synchronicities in vegetation change were also characteristic for the vegetation dynamics in low latitudes. We used sequence splitting to detect past vegetation change in the pollen diagrams and computed principal curves and rates of change to visually evaluate the changes in composition and dynamics. The results show that vegetation change occurred mostly during the second half of the Holocene with distinct episodes of change. The character of vegetation change is generally consistent with shifts to wetter conditions and agrees with inferred shifts of the South American Monsoon. Speleothems as well as the titanium record from the Cariaco Basin indicate several episodes of rapid shifts in the precipitation regime, which are within the dating uncertainty of the here detected periods of vegetation change (8900, 5900, 2800, 1200 and 550 cal yrs BP). Our results indicate that low latitude vegetation composition follows precession forcing of the hydrology, while change is often triggered and synchronized by rapid climate change much like in high and mid latitudes. Pollen diagrams document changes in the abundance of individual taxa and changes in the amount of woodland cover, while small compositional changes indicate a regional stability of vegetation types during the Holocene.