Vegetation of Akkerendam Nature Reserve, Northern Cape : delineation and dynamics over 100 years

• Published in: Bothalia Vol. 49; no. 1; pp. 1 - 9
• Main Authors: Hoffman, M. Timm, Van der Merwe, Helga
• Format: Journal Article
• Language: English; Portuguese
• Published: Silverton South African National Biodiversity Institute 2019; African Online Scientific Information Systems (Pty) Ltd t/a AOSIS; AOSIS (Pty) Ltd; South African National Biodiversity Institute (SANBI); South African National Biodiversity Institut
• Subjects: acocks; Biodiversity; Biodiversity Conservation; Botanical research; Climate change; Datasets; Ecosystems; Expansion; Identification and classification; Introduced species; Invasive species; Lists; Nature reserves; Photography; Plant communities; Plant populations; Prosopis; Rain; repeat photography; reserve management; species lists; Tables; Vegetation; vegetation dynamics; vegetation map; Vegetation mapping; Vegetation zones; South Africa; Karoo
• ISSN: 0006-8241; 2311-9284; 2311-9284
• DOI: 10.4102/abc.v49i1.2401

Background: Akkerendam Nature Reserve is the second oldest proclaimed municipal nature reserve in the Northern Cape, yet to date no vegetation map has been produced. The possible expansion of the reserve is under consideration.Objectives: To produce a vegetation map, classification and description of the vegetation of the reserve and proposed expansion area, and assess how the vegetation has changed over the past century.Method: Braun Blanquet methodology was used to produce a vegetation map. To quantify vegetation change, (1) relevés (a plot of phytosociological data) composed from Acocks’ species lists, recorded in 1954 and 1956, were compared with the phytosociological table, and (2) recent repeat photographs (2016) were compared to four images taken by Pole Evans (ca. 1920).Results: Three plant communities were identified within the reserve and expansion area; however, four subcommunities are only found in the proposed expansion area. Relevés compiled from Acocks’ species lists were absorbed into the phytosociological table indicating that no significant vegetation change has taken place in the last approximately 60 years. This study found 222 species in common with Acocks’ species lists; however, he did not list the alien invasive species Prosopis glandulosa. Comparison of repeat photographs with images taken nearly a century earlier suggests that, except for the impact of recent fires, the composition remained relatively similar.Conclusion: The phytosociological approach adopted has provided a map of the vegetation units of the study area, while the historical comparisons indicate that the vegetation of Akkerendam Nature Reserve has not undergone significant change over the last 100 years.