Fire and climate change impacts on lowland forest composition in northern Congo during the last 2580 years from palaeoecological analyses of a seasonally flooded swamp
Fire and climate change impacts on lowland forest composition in northern Congo during the last 2580 years from palaeoecological analyses of a seasonally flooded swamp
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DOI：
10.1177/0959683608098954
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发表时间：
2009-02-01
期刊：
影响因子：
2.4
通讯作者：
Bailey, Richard M.
中科院分区：
文献类型：
--
作者：
Brncic, Terry M.;Willis, Kathy J.;Bailey, Richard M.
赤道非洲中部低地的半常绿混交林可以包含许多次生植被元素。这就提出了一个问题，即哪些因素决定了该区域目前的森林构成。这种森林是在过去的自然气候变化和/或人为干扰后处于演替过程中的，还是一种稳定的森林类型？本文对位于刚果北部布拉柴维尔半常绿低地森林中的一个小型沉积盆地的沉积序列进行了多代理古生态分析，以解决这些问题。进行的分析包括化石花粉、地球化学和显微木炭。地球化学结果被解释为降雨量的替代指标，并显示刚果北部在过去2580年中经历了降雨量的变化，而微观的木炭浓度表明，毛刺从大约1240卡增加。时至今日，年复一年。对化石花粉组合的分析表明，尽管在整个序列中需要光照的分类群是这片森林的主要组成部分，但在1345年之前，森林中更多的是耐荫分类群。YR BP。1345卡后干旱和/或干旱增加。年BP，1240卡后火势增加。YR BP导致了一种半常绿森林，具有丰富的拓荒者，在过去900年中，即使在降雨量从400卡增加到100卡的时期，成分也一直保持着微小的变化。YR BP。这些数据可能会通过预测未来气候变化的潜在后果和伐木的影响来指导保护政策。
The mixed semi-evergreen forests in lowland central equatorial Africa can contain many elements of secondary vegetation. This raises the question of what factors have determined the current forest composition in this region. Is this forest in the process of succession after natural climatic variation and/or anthropogenic disturbances in the past, or is it a stable forest type? This paper presents a multiproxy palaeoecological analysis of a sedimentary sequence taken from a small sedimentary basin located in logged semi-evergreen lowland forest in northern Congo-Brazzaville which addresses these questions. Analyses undertaken included fossil pollen, geochemical and microscopic charcoal. Geochemical results were interpreted as a proxy for rainfall, and showed that northem Congo has experienced changes in rainfall during the past 2580 years, while microscopic charcoal concentrations indicated increased burring from approximately 1240 cal. yr BP to the present. Analysis of the fossil pollen assemblages showed that although light-demanding taxa were a major constituent of this forest throughout the sequence, shade-tolerant taxa were more abundant in the forest prior to 1345 cal. yr BP. Increases in aridity and/or droughts after 1345 cal. yr BP, and an increase in fire after 1240 cal. yr BP resulted in a semi-evergreen forest with abundant pioneers that persisted with minor changes in composition during the last 900 years, even during a period of increased rainfall from 400 to 100 cal. yr BP. These data may guide conservation policy by predicting potential consequences of future climate change and the impact of logging.