BIOTA activities on the observatories to date

• Vegetation mapping and monitoring (2006, 2007, 2008 & 2009)


• Soil survey (2008, results pending)

Findings of vegetation mapping:

• The vegetation of Ogongo was summarized into 3 vegetation classes, that were further categorized into 7 associations and 7 sub-associations :

• 1. Terminalia sericea - Combretum spp. shrublands vegetation class
• 1.1.Burkea africana - Croton gratissimus shrublands association
• 1.2.Combretum collinum - Terminalia sericea shrublands association


• 2. Colophospermum mopane - Acacia nilotica shrublands vegetation class
• 2.1 Hyphaene petersiana - Acacia arenaria shrublands association
• 2.1.1 Pechuel-Loeschea leubnitziae - Acacia arenaria shrublands sub-association
• 2.1.2 Hyphaene petersiana - Acacia arenaria shrublands sub-association


• 2.2 Colophospermum mopane - Eragrostis trichophora shrublands association
• 2.2.1 Colophospermum mopane - Enneapogon cenchroides shrublands sub-association
• 2.2.2 Colophospermum mopane - Willkommia sarmentosa shrublands sub-association
• 2.2.3 Colophospermum mopane - Eragrostis viscosa shrublands sub-association


• 2.3 Pennisetum glaucum - Amaranthus thunbergii crop fields association


• 3. Diplachne fusca - Nymphaea nouchali wetlands vegetation class
• 3.1 Diplachne fusca - Marsilea species oshanas association
• 3.1.1 Eragrostis cilianesis - Willkomia sarmentosa shallow oshanas sub-association
• 3.1.2 Diplachne fusca - Aponogeton junceus deep oshanas sub-association


• 3.2 Nymphaea nouchali - Nymphoides sp. ponds association

• The vegetation of Ogongo follows soil moisture gradient as inferred from a DCA ordination of the data (n = 227 releves)


• There was a high concentration of annual grasses in the study area which suggests some levels of degradation.


• On the communal areas, the Mopane shrublands are becoming increasingly replaced by crop fields, hence threatening the persistence of this vegetation unit


• The data collected in this study will contribute to the national baseline data of Namibia for compilation of the national vegetation map. These data can also be used as the basis for vegetation dynamics investigations in the study area.

References
DU PLESSIS, F. 2001. A phytosociological synthesis of Mopaneveld. M.Sc. Dissertation. Department of Botany, University of Pretoria, Pretoria.

GIESS, W. 1971. A preliminary Vegetation Map of Namibia. 3^rd Revised Edition. Dinteria 4:1-112.

KREIKE, E.H.P.M. 1995. The Ovambo agro-silvopastoral system: Traditional land use and indigenous natural resource management in central-northern Namibia, Forestry publication No.4, Directorate of Forestry, Windhoek.

Personal Communications
Mr. Ben. Strohbach, Principal Agricultural Researcher, National Botanical Research Institute, Windhoek