Database Report

Vegetation Database of the Okavango Basin

Rasmus Revermann, Manfred Finckh, Amândio Luis Gomes, Francisco Maiato Gonçalves, Johannes Wallenfang, Torsten Hoche & Norbert Jürgens

GIVD Database ID: AF-00-009	Last update: 2016-01-06
Vegetation Database of the Okavango Basin	Web address: http://www.future-okavango.org/
Database manager(s): Rasmus Revermann (rasmus.revermann@uni-hamburg.de); Manfred Finckh (manfred.finckh@uni-hamburg.de)
Owner: Working group Biodiversity, Ecology and Evolution of Plants, Biocentre Klein Flottbek, University of Hamburg, Germany
Scope: The vegetation database covers the Okavango River basin located in the countries of Angola, Namibia and Botswana. Sampling aims at covering all major vegetation types present in the basin. Additionally, detailed investigations are carried out at four research areas sized 100 km2. Vegetation plots are sized 20 m × 50 m with a 10 m × 10 m plot nesting in the centre. Grassland and wetland plots are in many cases sized 10 m × 10 m. On every plot all vascular plants species present including their estimated projected cover were recorded. Currently, the database holds vegetation-plots from semi-humid to semi-arid tropical woodlands (Miombo woodlands, Baikiaea-Burkea woodlands, Colophospermum mopane woodlands, and Thornbush savanna) as well as from geoxylic grasslands and Cyperaceae dominated wetlands of the Angolan Central Plateau. So far no plots of the wetlands of the Okavango Delta have been included but contributions from other researchers are welcome.
Abstract: The Okavango river basin, located in southern Africa and shared by the countries Angola, Namibia and Botswana, harbours large extents of (semi-)natural ecosystems. At the same time, it is a hot spot of accelerating land use change causing transformation of vegetation in many regions of the basin. However, knowledge on vegetation composition and plant diversity is very limited, especially of the upper reaches of the river in Angola. The Future Okavango (TFO) project aimed at closing this gap and initiated a plot-based vegetation survey in 2011. Here we present the resulting Vegetation Database of the Okavango Basin (GIVD ID: AF-00-009, http://www.givd.info/ID/AF-00-009). We used unsupervised classification of MODIS land surface phenology metrics to identify existing major vegetation units forming the basis of a random, stratified sampling design. However, sampling was largely constrained by limited access and the hazard of land mines, a legacy of the civil war in Angola. Furthermore, detailed sampling on four local study sites of 100 km2 representing the different macro-ecosystems of the basin was carried out. Vegetation plots followed a nested design of a 100-m2 plot resting in the centre of a 1,000-m2 plot. In every plot, we recorded all vascular plant species with their estimated, projected cover, vegetation height, cover of vegetation strata, topography, and intensity of land use activities. Furthermore, soil samples were taken and diameters of trees measured. Currently, the database has a focus on terrestrial vegetation, including Miombo woodlands and forests, geoxylic grasslands, Baikiaea-Burkea woodlands, and Colophospermum mopane woodlands. However, the database also includes plots of the tropical wetlands and peat bogs of the Angolan Central Plateau. The specific vegetation of the Okavango Delta is not yet included. The collected vegetation data will feed into a phytosociological classification and ecological modelling applications. Another objective is the identification of successional pathways after disturbance through land use. Ultimately, it will provide the basis for a vegetation map of the Okavango region.
Availability: according to a specific agreement	Online upload: no	Online search: no
Database format(s): other, BIOTA Base	Export format(s): MS Access, Excel, CSV file, plain text file
Plot type(s): normal plots, nested plots	Plot-size range (m²): 100 to 1000
Non-overlapping plots: 404	Estimate of existing plots: 0	Completeness: [NA]	Status: ongoing capture
Total no. of plot observations: 661	Number of sources (biblioreferences, data collectors): 1	Valid taxa: 456
Countries (%): AO: 78; NA: 11; BW: 11
Formations: Forest: 39% = Terrestrial: 39% // Non Forest: 71% = Semi-aquatic: 11% (Fresh water: 11%); Terrestrial: 60% (Non arctic-alpin: 60% [Natural: 45%; Semi-natural: 5%])
Guilds: all vascular plants: 100%
Plot size categories (%):
Environmental data (%): altitude: 100; slope aspect: 100; slope inclination: 100; microrelief: 100; surface cover other than plants (open soil, litter, bare rock etc.): 100; other soil attributes: 100; soil pH: 100; land use categories: 100; soil depth: 100; other attributes: texture; electric conductivity; ph in CaCl2, pH in KCl, pH in aq.dest.; cation exchange capacity; all from mixed surface sample (0-10 cm), 70-90 cm depth auger sample and in some cases 45-55 cm depth auger sample
Performance measure(s): cover: 100%; measurements like diameter or height of trees: 100%
Geographic localisation: GPS coordinates (precision 25 m or less): 100%; point coordinates less precise than GPS, up to 1 km: 0%; small grid (not coarser than 10 km): 0%; political units or only on a coarser scale ( above 10 km): 0%
Sampling periods: before 1920: 0%; 1920-1929: 0%; 1930-1939: 0%; 1940-1949: 0%; 1950-1959: 0%; 1960-1969: 0%; 1970-1979: 0%; 1980-1989: 0%; 1990-1999: 0%; 2000-2009: 0%; 2010-2019: 100%; unknown: 0%
Information as of 2025-11-03; further details and future updates available from http://www.givd.info/ID/AF-00-009

Rasmus Revermann* (rasmus.revermann@uni-hamburg.de)
Biodiversity, Ecology and Evolution of Plants, University of Hamburg, Ohnhorststr. 18, 22609 Hamburg, GERMANY
Manfred Finckh (manfred.finckh@uni-hamburg.de)
Biodiversity, Ecology and Evolution of Plants, University of Hamburg, Ohnhorststr. 18, 22609 Hamburg, GERMANY
Amândio Luis Gomes (algomes.jg.elb@gmail.com)
Faculdade de Ciências, Universidade Agostinho Neto, ANGOLA
Francisco Maiato Gonçalves (francisco.maiato@gmail.com )
Herbarium of Lubango, ISCED-Huíla, Rua Sarmento Rodrigues , 230 Lubango, ANGOLA
Johannes Wallenfang (johannes.wallenfang@gmail.com )
Biodiversity, Ecology and Evolution of Plants, University of Hamburg, Ohnhorststr. 18, 22609 Hamburg, GERMANY
Torsten Hoche (torsten.hoche@studium.uni-hamburg.de)
Biodiversity, Ecology and Evolution of Plants, University of Hamburg, Ohnhorststr. 18, 22609 Hamburg, GERMANY
Norbert Jürgens (norbert.juergens@t-online.de)
Biodiversity, Ecology and Evolution of Plants, University of Hamburg, Ohnhorststr. 18, 22609 Hamburg, GERMANY
* corresponding author