Over the past four decades palynologists have collected records of vegetational change from many sites in Africa. Reconstructions of palaeovegetation changes, based on pollen records, now exist from essentially all biogeographic regions and vegetation types in Africa. With the ever increasing number of sedimentary sequences containing fossil pollen and radiocarbon data becoming available from Africa, there is a need to initially collate the information, and secondly, to interpret the data at a range of temporal and spatial scales. Indeed, the centralisation of palaeoecological data is an important aim of the International Geosphere-Biosphere programme (IGBP).
Pollen databases that aim to provide an ecological synthesis of pollen records at the continental scale have been established for North America since 1992, and Europe and Latin America since 1994. Pollen data is also held at a global scale within the Global Pollen Database, based at Boulder, Colorado. Following a BIOME 6000 meeting at the University of Lund in 1995, the African Pollen Database (APD) was established with its operational base at the Laboratoire de Géologie du Quaternaire at CEREGE, Aix-en-Provence where it has been managed since 1996 under European Union support. This location was chosen as the base for the APD due to the considerable contribution made to African palynology from a number of personnel at this institute. CEREGE was also the base of the manager, Dr Hilaire Elenga whom has recently taken a post in Brazzaville, Congo. It is envisaged that the future management of the APD will be based at Brazzaville, with regional managers in eastern, northern and southern Africa. It is hoped this management structure will allow greater accessibility to the APD for indigenous palynologists, and enhance both the continental and regional understanding of African palynology. With an increasing number of African palynologists, many without direct access to type-slide material, it is envisaged that an additional role of the APD will be to provide a flora of African pollen types; this would be accessed either through the World Wide Web, or in a hard format for those without access to the internet.
Data held within the APD is supplied as original counts with original taxonomic identifications - this raw format allows for the standardisation of percentage calculations in terms of the pollen sums used or other grouping of data required by different initiatives, such as the production of plant functional types for BIOME model simulations and data - model comparisons. This bringing together of data, from hitherto disparate research groups, makes it possible to standardise pollen data in terms of the nomenclature used for palynomorphs, the level of identification and to assess the degree of chronological control. For a full review of the data format see Leduc et al. (1998). In addition to being placed within a hierarchical database, all data held within the APD is available in TILIA format. As well as providing the ability to manipulate, analyse and graph stratigraphic data, the TILIA program is accessible to all participants. The APD currently contains 110 pollen records comprising 80 continental, and 30 off-shore records. Associated with these records are information on latitude and longitude, site descriptions, the available dating control and stratigraphy. In addition to this information, there is a bibliographic reference list and a dictionary of palynologists. Complimentary information, such as macro-fossil data, is also stored although other micro-fossil data such as diatom records are not held. Information held within the APD is available to palynologists working at the local, regional or global scales, archaeologists and environmental modellers. The data is available to non-profit making organisations and for research purposes. In terms of use, the original counts remain the intellectual property of the contributor with normal ethics applying to co-authoring of publications.
The geographic location of Africa in the tropical region, the extensive latitudinal range (70° of latitude) the high altitude range (0 to in excess of 5800 m) and the well developed archaeological record over a range of time-scales, highlights the importance of pollen records of vegetation history from this continent. The interpolation of these records at a continental scale will allow for inter-hemispheric and inter-tropical comparisons of vegetation response to climate forcing and the impact of human activity, with the European and Latin American pollen databases respectively. The standardisation of data from different researchers allows for direct data comparisons between sites and can fuel exciting developments within African palynology; such as that provided by the recent production of vegetation maps for 6000 and 18000 yr B.P. through the BIOME project. If, as recently has been the case, additional dating support is required to strengthen the existing chronologies for specific time periods, such as 18,000 radio-carbon years B.P. (the last glacial maximum), the holders of the original sediments can be contacted and offered further radiocarbon support. Furthermore, the APD will promote scientific exchange and provide a platform for inter- and intra-disciplinary development. It is hoped this exchange will prevent the duplication of work and allow for the strategic setting of future palaeoenvironmental investigations.
For more information regarding the APD please contact.
Dr. Hilaire Elenga
CEREGE, B.P. 80, F13545, Aix-en-Provence, Cedex 4, France
Tel: +33 (0)4-42-97-15-86
Fax: +33 (0)4-42-95-15-99
E-Mail: elenga@cerege.fr