Current research projects

BelSPO

 

 

 

BelSPO BRAIN-be, 2014-2018

Genetic and paleoecological signatures of African rainforest dynamics (AFRIFORD)


The Central African rainforest hosts remarkable biodiversity that is currently under threat, yet its evolutionary history is barely known. To predict its fate in response to ongoing rapid environmental change, this project seeks to understand how past climate changes and the activities of ancient indigenous societies have shaped the current distribution and composition of African rainforests and the genetic diversity of their constituent tree species. This will be achieved through multi-disciplinary research integrating paleoecological analyses (palynology, anthracology) on lake sediments and soils, dendrochronology, vegetation modeling and population genetics. Phylogeographic patterns and molecular signatures of past differential selection and demographic events (population fragmentation, expansion) in characteristic tree species will be interpreted in relation to (1) detailed reconstructions of vegetation and fire dynamics in recent millennia using lake-sediment archives, (2) soil anthracological data to document the timing and spatial extent of Holocene fire disturbance, and (3) climate-vegetation model simulations of the climate and environmental processes controlling rainforest distribution and productivity. This conjunction of genetics, paleoecology and vegetation modeling will, for the first time, allow to build a cross-validated scenario of tree species response (distribution range, adaptation) to environmental change in the African rainforest.

 

 

BelSPO

 

 

 

BelSPO BRAIN-be, 2013-2017

Patterns and mechanisms of climate extremes in East Africa (PAMEXEA)


Recurrent drought is the principal weather-related hazard for vulnerable populations and socio-economic systems in semi-arid East Africa, and the quality of weather and climate prediction is a principal bottleneck hampering drought mitigation and adaptation to scarce and unpredictable water resources. The principal goal of PAMEXEA is to understand how processes of natural climate variability and their feedbacks interact with anthropogenic climate forcing to create trends in rainfall and drought at inter-annual and decadal time scales. To achieve this, PAMEXEA will (1) calibrate and extract 1000-year time series of seasonally-resolved information on past weather extremes from the annually-laminated sediment records of two lakes in north-central and southeastern Kenya; (2) quality-screen and synthesize all available climate-proxy time series from East Africa to produce a spatially-resolved regional history of past climate variability; (3) use inverse hydrological modeling to translate reconstructed local moisture-balance histories into time series of past rainfall; and (4) test the hind-casting performance of existing climate models as a guide to their skill in simulating future climate trends over East Africa under realistic combinations of natural and anthropogenic climate forcing. PAMEXEA results will contribute to better seasonal and longer-term forecasting by serving as reference frame for development of next-generation climate models.

 

 

ICDP + Ugent improved

 

 


International Continental Scientific Drilling Programme (ICDP), 2012-2018
UGent Coordinated Research Action, 2013-2018


Two glacial-interglacial cycles (ca. 250,000 years) of climate and ecosystem dynamics on the East African equator (DeepCHALLA)


Long climate records from (sub-)tropical continental regions provide an important counterpoint to the polar ice-core records from Antarctica and Greenland, and are crucial to resolve long-standing questions about the relative importance of tropical and high-latitude climate processes in generating spatial climate variation. DeepCHALLA aims to exploit the continuous sediment record of Lake Chala near Mt. Kilimanjaro in eastern equatorial Africa. This is a highly appropriate region to pursue a long equatorial climate record, because here seasonal migration of the Intertropical Convergence Zone (ITCZ) spans the widest latitude range in the world, and hence atmospheric dynamics associated with northern and southern hemisphere monsoon systems interact most strongly. Lake Chala’s proximity to the Indian Ocean also ensures its all-season location east of the Congo Air Boundary, the zone of convection between Atlantic and Indian Ocean moisture sources. Consequently the region is not directly impacted by the climatic effects of changes in tropical Atlantic thermohaline circulation, through which signatures of northern hemisphere glaciation are transferred to low-latitude continents. DeepCHALLA’s principal objective is to acquire high-resolution and well-dated proxy records of continental climate and ecosystem dynamics near the equator over the past ca.250,000 years, thus encompassing two complete glacial-interglacial cycles and the entire known existence of modern humans (Homo sapiens) in East Africa. The length of this climate archive, combined with the exquisite temporal resolution provided by finely laminated sediments, provides unique opportunities to increase understanding of tropical climate variability at inter-annual to millennial time scales, including the occurrence of short-lived weather extremes (droughts, floods) with disproportionate impact on regional water resources and economic activity. The project includes a special focus on differentiating the histories of three fundamental aspects of the tropical hydrological cycle: annual rainfall, effective moisture, and the duration/severity of seasonal drought. Documentation of long-term biodiversity patterns and the ecological dynamics of tropical savanna (grassland-woodland) ecosystems in response to changes in atmospheric CO2, temperature, moisture balance, and fire will help explain/predict the present-day/future prevalence of C3 and C4 plant species in tropical grasslands, and the past/future persistence of biodiversity hotspots in eastern Africa.


Report, 2012 ICDP Exploratory Workshop

 

 

EU FP7 MC

 

 


EU FP7 International Training Network, 2013-2017


Resilience in East African Landscapes: Identifying critical tresholds and sustainable trajectories in past, present and future (REAL)


REAL focuses on the temporal, spatial and social dynamics of climate-human-landscape interaction in East Africa during the last millennium, with particular reference to dry environments of the Rift Valley and Laikipia plateau in central Kenya, and the Pangani and Amboseli basins in northern Tanzania and south-eastern Kenya. With a mixed topography between dry lowlands and wetter adjacent uplands, these areas present a range of human habitat along a natural gradient of land and water resources. The core objective of REAL is on understanding how indigenous societies, landscapes and ecosystems have responded to the large natural climate variability that is endemic to East Africa, as a key to develop strategies for adaptation to future climate change. Within the REAL programme, two UGent PhD projects use palaeoecological reconstructions of past human-environment interaction driven by natural climate variability to re-evaluate current estimates of indigenous landscape use based on extrapolated historical demographic data.

 

 

Vliruos

 

 


VLIR-UOS VLADOC, 2013-2017


Vulnerability of tropical crater lakes to water-quality loss: a natural experiment in western Uganda


In East Africa, loss of water quality is a very real problem, as sustainable water resources are naturally scarce. This study assesses how the physical limnology of tropical African crater lakes, specifically their relative depth and frequency of deep water-column mixing, affects the vulnerability of their water quality and fisheries to different types of land-use within their catchment. This is achieved through comparative study of water-column mixing, algal productivity, nutrient budgets, and land use in 25 crater lakes in western Uganda. Using field data on the relationship between physical limnology and trophic status (water quality) in the study lakes, a model will be developed which enables predictions on the effects of specific lake management on other small tropical lake ecosystems in East Africa. This will allow strategic water-resource management to decide which lakes are most suitable for economical activity, and which lakes should be set aside for extraction of drinking water. Also it will allow to predict the regional water-resource consequences of increasing or decreasing precipitation resulting from climate change.

 

 

NatGeo + FWO

 

 

 


National Geographic Society, 2011
FWO-Vlaanderen, 2012-2017


Zooplankton community dynamics in East African mountain lakes: integration of (palaeo-) limnology and (palaeo-) genetics


This project investigates the impact of decadal to century-scale variability in the climate (rainfall and temperature) of central Kenya during the late Holocene (the last ~2000 years) on the size and temporal dynamics of the glaciers on Mount Kenya, and on its high-mountain (Afro-alpine) aquatic ecosystems. This objective is pursued through multi-proxy analysis of long, dated sediment records from lakes on Mount Kenya itself and from Lake Bogoria in the nearby Rift Valley. Associated analyses of current lake-water chemistry and biological limnology are important for the correct interpretation of changes in the sedimentological and fossil biological proxies occurring in the sediment cores, from which we derive quantitative estimates of past climate changes in the region. Reconstruction of climate-driven changes in the depth and salinity of Lake Bogoria will produce the reference framework of regional climate history, permitting elucidation of temperature and precipitation controls on the advance and retreat of Mount Kenya glaciers. From Mount Kenya only, we will also collect plankton samples for genetic analysis of a selected group of zooplankton (water fleas, a group of microcrustacea) to help distinguish between native and exotic species occurring in Mount Kenya lakes today. Documentation of the current distribution of those exotic (invasive) species in relation to local habitat quality and co-occurring native species will allow rigorous evaluation of their current and future impact on the ecology of Mount Kenya lakes.


Mt.Kenya Project flyer, Kenya Wildlife Service
Programme, Mt.Kenya project training workshop
Programme, Kenya Soda Lakes conference

 

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