Most people don’t think of the inner reaches of Sydney Harbour as being a pristine marine environment and while it’s true that biodiversity there isn’t in great shape, it’s not for the reason most people think. While parts of the habour are quite polluted it’s not water quality that keeps marine life away, its lack of suitable habitat.
Before European invasion most of the harbour’s shoreline was made of gently sloping rocky surfaces that were exposed when the tide was low and covered when it was high. This created an extensive area of rockpools that served as ideal habitat for a wide range of marine plants and animals such as crabs, snails, small fish and starfish.
Fast forward to the 21st century and over half of this sloping area is gone, replaced with vertical sea walls that provide virtually no intertidal habitat. Water quality in the harbour can be pretty poor but this is much less of a problem for its wildlife than the lack of suitable living space. Luckily this problem is easy to solve.
In 2010 former Greens Councillor Chris Harris got in touch with a group of researchers from the University of Sydney who were looking to trial an innovative way of restoring marine habitat in Sydney Harbour. Their plan involved attaching ceramic flower pots to the sea walls to allow rock pools to form at low tide and trials carried out on the north side of the habour showed the improvements in biodiversity this produced were significant. Chris moved a motion to have City of Sydney partner with these researchers in conducting more trials and while the motion was supported unanimously there was sadly little progress after that.
However last year I saw an opportunity to restart the stalled process when Council began work to replace some ageing seawalls on the foreshore at Glebe. I met with Council engineers and showed them some of the research on how changes to seawall design, including installing flower pots, can improve biodiversity. They were impressed by the effectiveness and simplicity of the idea and I was pleased to see as the new year began that the idea had been taken up.
I’m very much looking forward to seeing the results of this trial and I hope that, should it prove succesful, we’ll see a lot more flower pots appearing on seawalls in Sydney. Improving water quality is still an important goal that all levels of government should be working on, but for now it seems like the harbour’s other big environmental problem is well on the way to being solved.