The average person is generally unaware of the importance of Mangrove
ecosystems which, according to researcher Professor Norm Duke of Queensland's
James Cook University, “take in 50 times more carbon than tropical forests
by area and act like nature's kidney”.
There are many species of mangroves, and Australia is home to 7% of the
world's population, but our mangroves are under serious threat, not only from
sea-level rise resulting from climate change, but seemingly from warming oceans
as well.
James Cook University researchers have noted that huge areas of
mangroves are dying along hundreds of kilometres of shoreline in Queensland and
the Northern Territory, where entire populations have turned “a ghostly
white”, leading to speculation that it could be the result of a period of
hot water in the southern Gulf of Carpentaria.
Professor Duke compared the event to current coral bleaching on the
Great Barrier Reef, which is also the result of warmer ocean temperatures. He pointed
out that the mangrove deaths coincided
with the same period when water temperatures were higher than normal. However,
he was careful to say that more evidence was needed before any conclusions
could be drawn.
Anecdotal
evidence from fishermen at the small Gulf town of Karumba, a town that relies
heavily on the fishing industry, suggests the mangrove die-back is also
impacting negatively on fish stocks, a correlation Professor Duke agrees is
what we would expect, as mangroves provide critically important breeding
habitat for many fish species.
The
Clarence River estuary is also home to a variety of mangrove species, with five
species known to occur on the NSW north coast. They too are under threat, not
from warming oceans, but from coastal development. The push by Council to
rezone parts of the lower river as “working waterfront” to encourage the
development of marine industries, could be just the thin end of a very much
larger wedge, with the massive Yamba Port and Rail proposal raising its ugly
head once again. Should that monstrous proposal ever receive the green light,
mangroves could become virtually extinct in the lower Clarence.
- John Edwards
This article was originally published in the VOICES FOR THE EARTH column in The Daily Examiner on July 11, 2016.
