Studies on late Quaternary environmental dynamics (vegetation, biodiversity, climate, soils, fire and human impact) on Mt Kilimanjaro
Studies on late Quaternary environmental dynamics (vegetation, biodiversity, climate, soils, fire and human impact) on Mt Kilimanjaro
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发表时间：
2013-09
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通讯作者：
L. Schüler
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作者：
L. Schüler
对乞力马扎罗山不同关键区埋藏土壤的沉积物进行了研究，以恢复以前的景观并预测未来的景观动态。这有助于在更大范围内更好地了解地方和区域生态系统、气候、火和土壤动态，生态系统动态及其对环境变化的反应，不同生态系统的联系和分离，以及它们对东非生物多样性热点发展的作用。乞力马扎罗山是全球维管植物多样性中心之一。它是地球上生物多样性最丰富的地区之一。尽管现有生态系统具有与生俱来的价值和重要性，但我们面临着这些基本上未被开发的栖息地日益灭绝的问题。实施古环境研究至关重要，因为过去的进程在生态系统和生物多样性的发展中发挥着重要作用。本文通过对晚第四纪植被、气候和火灾动态的研究，以期对现代和未来的生态系统动力学有更深入的了解。通过对两个沉积物记录的孢粉学和多指标分析，恢复了过去的植被动态，揭示了影响因素。位于乞力马扎罗山东南坡海拔2780米的茂迪陨石坑的花粉、木炭和沉积学记录是赤道东非最长的陆地记录之一，使人们对最后一次冰川早期的植被和气候动态有了有趣的了解。来自海拔2650米的山地森林遗址的WeruWeru花粉记录详细地重建了晚期冰川和全新世期间植被对环境变化的响应。我们的结果表明，过去的气候变化导致植被带沿海拔梯度移动。花粉档案显示，上部植被带(橡胶带和山地林带)至少有1100米的变化，但强调了乞力马扎罗山作为类似于东弧山的山地森林物种的冰川避难所的作用。火在控制芒迪陨石坑周围的橡胶质带和树线的发育和抬升方面发挥了重要作用。在全新世，没有观察到人类活动的影响，因为既没有记录到更高的火灾活动，也没有记录到嗜水性植物的扩散。乞力马扎罗山沿海拔梯度的现代花粉雨研究表明，建立现代花粉-雨-植被关系对于校准和解释来自山区的化石花粉记录是至关重要的。这些结果有助于更准确地利用化石花粉数据重建东非山地森林的潜在植被及其动态，并改进该区域过去的气候重建，以便更准确地比较数据和建模。
Sediments of buried soils from different key areas at Mt Kilimanjaro are studied to reconstruct former and to predict future landscape dynamics on Mt Kilimanjaro. This contributes to a better understanding of local and regional ecosystems, climate, fire and soil dynamics in a larger context, ecosystem dynamics and their reaction on environmental changes, connections and disjunctions of different ecosystems and their role for the development of the biodiversity hot spots in East Africa. Mt Kilimanjaro represents one of the global centres of vascular plant diversity. It is one of the most biodiverse regions on earth. Despite the innate value and importance of the existing ecosystems, we are confronted with the progressing endangerment of these largely unexplored habitats. The implementation of palaeoenvironmental studies is crucial since past processes play a major role in the development of ecosystems and biodiversity. In the present study, investigations of late Quaternary vegetation, climate and fire dynamics are carried out in order to gain a deeper understanding of modern and future ecosystem dynamics. Palynological and multi-proxy analyses of two sediment records are used to reconstruct past vegetation dynamics and to reveal influencing factors. The pollen, charcoal and sedimentological record from the Maundi Crater, located at 2780 m elevation on the south-eastern slope of Mt Kilimanjaro, is one of the longest terrestrial records in equatorial East Africa, giving an interesting insight into the vegetation and climate dynamics back to the early last Glacial period. The WeruWeru pollen record from a montane forest site at 2650 m provides detailed reconstruction of the vegetation response to environmental changes during the Late Glacial and the Holocene. Our results suggest that past climate change caused the vegetation belt to shift along the elevational gradient. The pollen archives reveal shifts in the upper vegetation zones (ericaceous zone and montane forest zone) of at least 1100 m but underline the role of Mt Kilimanjaro as a glacial refuge for montane forest species similar to that of the Eastern Arc Mountains. Fire played an important role in controlling the development and elevation of the ericaceous zone and the tree line around Maundi crater. During the Holocene no anthropogenic impact can be observed, since neither higher fire activity nor a spread of hemerophilic plants is recorded. The modern pollen-rain study along the elevational gradient on Mt Kilimanjaro reveals that it is crucial to establish a modern pollen-rain – vegetation relationship for the calibration and interpretation of a fossil pollen record from a mountain site. The results facilitate the confident use of fossil pollen data to reconstruct more precisely potential vegetation and its dynamics in East African montane forests and also to refine past climate reconstructions in this region for a more accurate comparison of data and modelling.