18 | NATURE 16
26 February 2020
Estuaries and wetlands - together we can preserve them Writer Klaus Schmitt
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stuaries are one of the most important features of the South African coastline; they are tranquil areas of high productivity and play a vital role in the life cycles of many plants and animals – especially as a nursery for fish. Situated at the interface between fresh and marine waters, estuaries are among the most biologically productive ecosystems in the world and are of great ecological and economic importance. These words were written by Dr Anina Lee in The Village NEWS of 30 October 2019. Friends of the Bot River Estuary and Environs (Botfriends) fully agree with this ecological appreciation of both estuaries and wetlands as high-value ecosystems. The Bot River Estuary is the largest in the Overstrand. Its surroundings include large badly-degraded wetland areas. We are highly concerned about the conservation of these environmental assets. Among the most serious threats are the aggressive and rapid spread of invasive alien vegetation at the expense of the indigenous fynbos, and the pollution and drying up of the wetlands.
This is why the Botfriends have come up with community-driven activities in alien clearing and wetland preservation. About 30 ha have been cleared thus far with our private resources. Significant as this is, these efforts need to be scaled up urgently. This is why the Botfriends have come up with a plan to deal with large parts of the area south of the R43, from Rooisand to Hawston. This area once boasted high biodiversity and many wetlands. Alien invasion has dried up the wetlands and increased the fire risk. Several sections have been abandoned, including demarcated green areas. Efforts towards controlling the invasive species have been limited and have sometimes compounded rather than relieved the problems. If not eradicated properly, for example when infested areas are just mowed or clearing is not followed up, aliens regrow fast and suppress the fynbos vegetation more vigorously than before. The Paddavlei near Hawston has changed from an open water body to a polluted swamp that is a quarter of its original size. In 2018, a fire in an alien-infested area adjacent to Fisherhaven could not be controlled even with helicopter support. It occurred
under gentle wind conditions. Higher wind could have caused a disaster similar to the great Betty’s Bay fire of 2019. Rehabilitating The shore of the Bot River Estuary near the mouth. On the dune to the right, fynbos vegetathe wetlands tion has already recovered a year after alien clearing by Botfriends. The spot to the left in the will increase foreground was cleared a few months ago. To the left, the dense woody vegetation shows their wauncontrolled Port Jackson (Acacia saligna) and Australian Myrtle (Leptospermum laevigatum) ter-holding having suppressed the slower-growing fynbos. PHOTO: Klaus Schmitt capacity and the inflow An area of about 3 000 ha has been off and flooding. The Botfriends Alien to the Bot River Estuary, a declared identified as a priority for further Clearing Project aims to (1) remove RAMSAR site. It will also enhance the clearing and a project proposal has alien plants in the Bot River enviwater quality through the wetlands’ been drawn up for submission to rons, (2) re-establish wetlands in the filtering function. In addition, these potential donors. Meanwhile we conwetlands fall within three biodiversity Bot River area and demarcate three biodiversity corridors, (3) reduce the tinue with our own limited resources, corridors between the estuary and fire risks to manageable proportions, aiming to involve more local roleplaythe mountains. (4) contribute towards an environers and contributors, both private and communal. All contributions are mental management strategy for a Protected corridors allow free spread greater area that involves the relevant welcome, be it in the form of financial and movement of indigenous flora donations, fundraising ideas, labour, stakeholders. and fauna. Such ecosystem services advice or logistics. become ever more important, as While clearing areas in and around climate change is a reality and South Financial contributions to the alien Fisherhaven, Botfriends have tested Africa is a hotspot. Here warming clearing project will be tax-deductthe effectiveness and cost-efficienwill most likely be twice the global cy of different methods. Our team ible. For further info, please contact average, while rainfall will be scarcer can serve as the nucleus for further Michael Austin at botvlei@gmail. and more erratic, and other extreme expansion of a clearing workforce. com or visit www.botfriends.org.za. events will likely result in further run-
