Studies on late Quaternary environmental dynamics (vegetation, biodiversity, climate, fire and human impact) on Mt. Kilimanjaro, comparing the dry northern with the wet southern slopes
Final Report Abstract
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. 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 several sediment and palaeosoil records were used to reconstruct Late Glacial and Holocene vegetation dynamics on Kilimanjaro’s wet southern slope and the dry northern slope, and to reveal influencing factors. The palaeoenvironmental 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. Several pollen, charcoal and phyotolith records from montane forest sites on southern and norther slope provide detailed insight into vegetation response to environmental changes during the Late Glacial and the Holocene. The pollen archives reveal shifts in the upper vegetation zones (Erica 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 like that of the Eastern Arc Mountains. The succession of different forest types proposes that past environmental changes did not only cause an elevational shift of vegetation but also profound re-structuring of the forest ecosystems. Our results suggest that past climate change caused the vegetation belt to shift along the elevational gradient, however plant taxa showed individualistic responses rather than as closed plant communities; results further point out that local environmental conditions are important in vegetation response of East African Mountains. Such local conditions should not be neglected for projections of future vegetation changes for setting up conservation plans for montane forest, essential in terms of water resources for lowland areas in tropical semi-arid regions such as in East Africa. Fire plays an important role in controlling the development and elevation of the Erica and alpine zone and the tree line at elevations higher than 3700 m asl. During the Holocene no anthropogenic impact can be observed at Mt Kilimanjaro, since neither increased fire events nor a spread of hemerophilic plants is recorded. Modern pollen-rain studies along the elevational gradient on Mt Kilimanjaro as well as pollen dispersal studies 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 to refine past climate reconstructions in this region for a more accurate comparison of data and modelling. Apart from achieving comprehensive understanding of the past vegetation changes and identification of environmental conditions and their impact on local and regional ecosystem dynamics in the Mt Kilimanjaro area, the results of this project complement existing investigations in Tropical East African Mountains. 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. The comprehensive and detailed results of this palaeocological and -climatological project should allow the improvement of the anthropogenic use of natural resources by integrating land use within the boundaries of the natural ecosystem, considering the long-term effects of climate change, the potential of the land for different economic activities, and nature protection.
Publications
- 2012. Vegetation, climate and fire-dynamics in East Africa inferred from the Maundi crater pollen record from Mt Kilimanjaro during the last glacial-interglacial cycle. Quaternary Science Reviews 39, 1–13
Schüler, L., Hemp, A., Zech, W., Behling, H.
(See online at https://doi.org/10.1016/j.quascirev.2012.02.003) - 2013. Studies on late Quaternary environmental dynamics (vegetation, biodiversity, climate, soils, fire and human impact) on Mt Kilimanjaro. Doctoral Thesis, University of Göttingen, GCBE - Göttingen Centre for Biodiversity and Ecology, Göttingen, 191 pp.
Schüler, L.
- 2014. Pollen-based temperature and precipitation inferences for the montane forest of Mt Kilimanjaro during the last Glacial and the Holocene. Climate of the Past Discussions 10, 195–234
Schüler, L., Hemp, A., Behling, H.
(See online at https://doi.org/10.5194/cpd-10-195-2014) - 2014. Relationship between vegetation and modern pollen-rain along an elevational gradient on Kilimanjaro, Tanzania. The Holocene 24 (6), 702–713
Schüler, L., Hemp, A., Behling, H.
(See online at https://doi.org/10.1177/0959683614526939) - 2016. Atlas of pollen and spores and their parent taxa of Mt Kilimanjaro and tropical East Africa. Quaternary International 425, 301–386
Schüler, L., Hemp, A.
(See online at https://doi.org/10.1016/j.quaint.2016.07.038) - 2018. Late Quaternary ecotone change between subalpine and montane forest zone on the leeward northern slope of Mt. Kilimanjaro. Journal of Vegetation Science (3), 459-468
Montade, V., Schüler, L., Hemp, A., Bremond, L., Salamanca Duarte, A.M., Behling, H.
(See online at https://doi.org/10.1111/jvs.12639) - 2018. Studies on late Quaternary environmental dynamics (vegetation, biodiversity, climate, soils, fire and human impact) on Mt Kilimanjaro. In: Hemp, C. et al. (Eds.), The KiLi Project: Kilimanjaro ecosystems under global change. Linking biodiversity, biotic interactions and biogeochemical ecosystem processes. Senckenberg Gesellschaft für Naturforschung, Frankfurt/Main, Germany, pp 86-93, ISBN 978-3-929907-96-4
Schüler, L., Hemp, A., Behling, H.
