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Baseline images.
A powerful tool in longterm studies of habitats is the use of fixed point photography. By selecting focal points and taking photographs of the habitat from the same vantage point will document any change that occurs at the site.
With a glocal focus on climate change and th eimpact that it has on habitats, it is the ideal citizen science project to monitor either degardation or regeneration.
Reef Regeneration.
Using fixed point photography, the Strandloper Project has been able to demonstrate significant reef regenration at a site at Gericke's Point since October 2014. We have also used this method to document the regeneration of a reef site rendered barren of any sessile or encrusting floral and faunal organisms.
Image 1. The original image of our first fixed point photogtaphy site in October 2014 distinctive in the abscence of sea fans growing on the reef.
Image 2. Photographed in December 2019, the image clearly shows the succesful recruitment of Sea fans and the proliferation of corlline algae.
Impact of Climate Change.
While we are still studing the mechanisims which brought about the spontaneous recruitment of sea fans at this and other sites at Gericke's Point, it would appear to be a combination of direct and indirect climate change factors. The direct climate change influence is the simple progressive increase in the mean water temperature over the period of recruitment.
The secondary factors include the decrease of the inflow of fresh water and agrichemicals as a result of the decreased rainfall driven by climate change during the same period..
The Swartvlei Estuary mouth is a blind estuiary that is closed by a sand bar during periods of low rainfall. In 2014 the status of the mouth was open for between 18 and 22 months and closed for two to 5 weeks. By 2018 the cycle had flipped to closed for 8 to 12 months and open for between 3 and 5 weeks.
The combined sea temperature increase, reduce inflow of fresh water and agrichemicals into the ocean are most likely the factors that supported the recruitment of sea fans in particular at this site. A review of video content of this and other sites between 2014 and 2022 indicate that the recruitment of sea fans and some soft coral species was wide spread around the peninsula of Gericke's Point.
While the extended period of the estuary mouth being closed has been a possible benifit for marine life on the reef at Gericke's Point, studies are required to determine what the impact of the the cntained agrichemicals in the Swartvlei Estuary are on the aquatic fauana flora.
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