Few long-term climate and environmental records are available for southeast Africa where millennial scale shifts in the north-south position of the Intertropical Convergence Zone (ITCZ) and changes in Indian Ocean sea surface temperatures interact with local controls (e.g., fire, hydrology) to influence vegetation and ecosystem dynamics. Reconstruction of late-Pleistocene - Holocene environmental change from peat sediments obtained from Mount Gorongosa, central Mozambique, provides insight into vegetation, climate and disturbance interactions over the past c. 27 kyr. During the late Pleistocene, cool and wet climatic conditions supported Podocarpus forest and Ericaceae-heathland until drier conditions led to grassland expansion and a hiatus in peat deposition between c. 22.5 and 7.2 cal kBP. Increased temperatures and fire activity since c. 7.2 cal kBP led to further expansion of grasslands. Continued warming helped maintain grasslands and fostered a diverse mix of Podocarpus forest with a large number of subtropical trees and miombo woodland taxa (especially Brachystegia spp.) until regional land-use associated with the rise of Iron Age activity promoted an increase of disturbance related taxa over the last 1-2 millennia. Recent migration of people onto the Mount Gorongosa massif in the last fifty years are linked to an increase in fire activity that is unprecedented in the 27 kyr record, resulting in shifts in vegetation composition and structure. This long-term record of environmental change from central Mozambique highlights complex interaction between overlapping climatic influences and documents important vegetation transitions linked to millennial scale climatic controls, disturbance processes and more recent land-use change from a region where few records exist.
Bibliographical noteFunding Information:
We thank Gorongosa National Park ecologist Tongai Castigo, USDA staff Martin Sampson and University of Eduardo Mondlane student Hidigo Bape for assistance in the field and A. Niehus for the careful palynological preparation of the sediment samples. We thank E. Worobiec and L. Scott for fruitful discussions regarding pollen and spore types and vegetation history. We also thank two anonymous reviewers for their immensely helpful comments. Geochemical analyses were conducted at LacCore (National Lacustrine Core Facility), University of Minnesota-Twin Cities. This research was supported by National Geographic Committee for Research and Exploration grant# 8684-09 .
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- East Africa
- Fire history
- Grassland expansion
- Podocarp forest
- Southern Africa
- Vegetation change