The Sea’s Tiny Creatures

Just like the terrestrial vegetation in the coastal section of the Namaqua National Park (NNP), the intertidal organisms between the high and low water marks are unique.

shells (4)They exist nowhere else in the world in such congregations. This, according to Dr Maya Pfaff, Biodiversity and Coastal researcher for the Department of Environmental Affairs: Oceans and Coasts, is one of the reasons why the coastal zone should be protected and monitored.

Fortunately, this coastal section of NNP between the Groen to the Spoeg River, has recently been earmarked as a Marine Protected Area (MPA), the first one in the Namaqua bioregion. This will mean stricter regulation when it comes to catching or harvesting marine species and other types of exploitation, such as mining. However, monitoring the different ecosystems of the MPA will also be important to determine what environmental impacts of human activities have on marine systems.

Four spots have been marked, two sites inside the proposed MPA and two outside, where a Rocky Shore Monitoring Programme started at the end of August 2015 through efforts of the Department of Environmental Affairs and SANParks. The monitoring will include the overall appearance of the shoreline to monitor sediment movements, the biodiversity of algal and animal communities on intertidal rocks, and changes in sea temperature that indicate environmental change. These features will be recorded every 3 months, hopefully for many years, allowing long-term data comparison and assessments of the effectiveness of the MPA.

The initial phase of the monitoring programme will serve to establish biodiversity baseline information inside and outside the proposed MPA area, which will act as reference of the state of the environment before and after proclamation, says Pfaff. “We chose sites at which surveys had been conducted more than a decade ago to find out if there have been long-term changes in biodiversity due to climate change and alien invasions,” she explains. Since then, changes have already been picked up in the limpet community.

Limpets reach exceptionally high densities and sizes and some Namaqua species feed on kelp by trapping and cutting off the kelp fronds as they get swept over the rocks. Over the last 40 years, the alien invasive Mediterranean mussel has invaded a wide band in the intertidal zone, thereby displacing indigenous species, especially limpets. Pfaff says that in addition, mining activities in areas adjacent to the park could also lead to increased sediment loads on the coastal environment and potential negative impacts on rocky shores. “It is therefore critical that we keep updated with the monitoring protocol to advise on environmental effects and recovery measures for coastal ecosystems,” she says.

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Pfaff says monitoring is important because MPAs act as comparable ‘pristine’ reference sites when assessing the impacts of such pressures on areas outside of it. “Monitoring biodiversity inside versus outside the MPA also informs managers of the effectiveness of the MPA in conserving certain species or communities.”

A variety of different methods are used in the monitoring process. Marine section ranger Piet Schreuder says that three transects were permanently marked at each of the four sites. By taking photographs of 30cmx30cm squares along those transects during spring low tides, they look at changes in species cover that occur in the intertidal rocky shore. If, for example, the sea level was to rise due to climate change, this programme would detect the changes in species distributions immediately. Methods were selected to invest minimum sampling efforts while achieving maximum results. These range from fixed point photography to monitor sediment dynamics, quick assessments to determine the species present, target surveys for observing specific species and data logging to capture the ocean temperature. In addition expert surveys were conducted to verify that the photographic method captures all necessary ecological information. All methods provide their own challenges; hence a combination of quick and detailed techniques make is chosen to achieve best results with minimal effort.

Schreuder says that they are excited about the joint DEA-San Parks monitoring programme. “One usually has questions without answers, so we will hopefully be able to answer some of those in the future,” he says.

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Words: René de Klerk

Content courtesy of SANParks Times:

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