A database of aquatic weeds and biocontrol in South Africa after 6 years of national surveys: a tool for researchers and managers of South African water bodies.

A database of aquatic weeds and biocontrol in South Africa after 6 years of national surveys: a tool for researchers and managers of South African water bodies.
Matthew C. Parkinson
Department of Zoology and Entomology, Rhodes University, Grahamstown, 6140, South Africa.

The  database  is  primarily  the  compilation  of  data  from  6  years  (since  2008)  of  field  surveys conducted by the Biological Control Unit of the Rhodes University Department of Zoology and Entomology, funded by Working for Water. Currently the database holds over 900 sites and over 1 500 individual records, with each of the major weeds at a site during a given year making up one record. The survey focusses on the 5 floating aquatic weeds: red water fern, Azolla, Kariba weed, Salvinia molesta, water hyacinth, Eichhornia crassipes, parrot’s feather, Myriophyllum aquaticum and water lettuce, Pistia stratiotes. Data collected during these national fieldtrips pertain to the species present at a site, the extent of the cover of the water body by each species, the presence of biological control agents and an assessment of general plant health and damage caused by the biological control agents that were present. Digital photographs were also taken at most of the sites that were visited. The data are useful firstly in documenting where the different weeds occur within the country and the extent to which biological control has been implemented in different regions, and secondly contribute towards the long-term monitoring and assessment of management strategies that have been implemented for various water bodies. The data, which is freely available to any person upon request, will allow managers to adopt an adaptive management approach, whereby the efficacy of different strategies can be assessed and modified as and when necessary. Parrot’s feather, and its control agent Lysathi sp., is presented as a case study.