Savanna Forest Boundary Transition in West Africa –Coupling the Energy Balance and Hydrology and Carbon Cycles across the Biome zot

Project Team: Adu-Bredu, S. and Ametsitsi, G.K.D.

Collaborators: Nature Conservation and Plant Ecology Group, Wageningen University

Background

GEOCARBON is an European FP7 project with a global perspective, with the ultimate aim to lay the foundations for an operational Global Carbon Observing and Analysis System in support to both science and policy. Th e loss of most transitional forest over a distance of 150 km nationwide (“savanisation”) particularly in the zone of transition (ZOT) in Ghana has been dramatic. It has been a source of livelihood for fringe communities and supplies ecosystem services such as charcoal, grazing and medicinal herbs, in addition the ZOT has a unique biodiversity conservation value. The adjacent forest and savanna systems in the ZOT are uniquely de fined by space and time scale and interactions, which support a mix of these vegetation types under the same climatic conditions. In this project, the aim is to study vegetation interaction with soil, climate and edaphic factors in a forest savanna-ecotone in West Africa, to elucidate the dynamics of vegetation change in the light of fi re mediated feedbacks and alternate states of forest and savanna. The study is being conducted in the Kogyae Strict Nature Reserve in Ghana. Th e study has four components which would determine the following: (i) how edaphic properties (e.g.nutrients and soil depth) a ffect vegetation structure and phenology (ii) eff ects of canopyclosure on fire dynamics (iii) eff ects of edaphic properties on physiological activity in trees (e.g. sap flow) and (iv) the resulting seasonal variation of exchange of CO2 and latent and sensible heat in this ecotone. Soil physical and chemical properties, fi re characteristic measurements and land atmosphere feedbacks will be analysed over a two year period. Th e research outputs will include a PhD thesis, scientific publications and presentations both locally and internationally at workshops and seminars. Th is project adapts the state of the art technology to measure land atmosphere feedbacks and energy balance. A sustainable 36 m lattice tower  above canopy equipped with eddy covariance gadgets has been built and running, measuring energy fluxes and carbon dioxide exchange. Th is is the first of its kind in the transition zone of Ghana. In addition, 35 permanent plots have been established in the forest, forest-savanna (mixed) and savanna sites within the reserve. Studies on fire dynamics has been conducted for two years, while data on soil depth variation and moisture distribution was collected. The phenology of trees, sapflow rate and resistance to fi re is being studied. Th e project has been sustained by high level of commitment by collaborative partners which created opportunity for training of MSc and PhD Students.  Th e management of the project seeks to establish a permanent research site in the transition zone and a paradigm shift in FORIG’s research scope and dimension. Project management has established a mechanism to address known and unforeseen challenges in view of the highly technical nature of some components.