This blog is part of the series ‘What the resilience of the Whitsundays can teach the world at the beginning of the hurricane season.’
In previous post I described how beneficial mangroves can be for human and for nature, unfortunately, these capacities are too often undervalued.
Despite these benefits, mangroves are under treath worldwide. Protected areas cover only some 35% of the world’s remaining mangrove areas, which are even still exposed to some levels of (sustainble) fishing, harvesting of non-timber forest products and tourism.
Among the threats for mangroves there is pollution, waste dumping, draining or unmanaged timber extraction, as well as the building of dams and the use of freshwater for crop irrigation, which both reduce freshwater supplies and change sediment loads in rivers. Both increase salinities and reduce sediments can lead to erosion and decrease the mangroves soil-forming capability.
On the other hand, the study of Nature Conservancy and Wetlands International says that thus far no mangrove species are growing slower in the warming world.
Mangroves in Australia
The Australian Government, Department of the Environment and Energy, acknowledges this ability of the mangroves. Yet, the current state of the Australian mangroves is not what it used to be. According to the website, ‘Coastal mangroves and saltmarshes have historically been undervalued and considered by many to be wastelands. As a result, many areas have been drained, reclaimed, become degraded from a range of human activities or otherwise lost.’
Mangroves can be found throughout Australia’s coastal region, especially in the north and east, covering a total area of about 11,500 square km. While Australia houses 7% of the world’s mangroves, 17% of the original Australian mangroves have been destroyed since European settlement.
Florida, an extreme vulnerable US’ state for climate change as in rising sea levels and increasing storms and flooding, has acknowledged the importance of mangroves as natural buffers. Research estimated that mangroves protect $13 billion worth of US’ property a year from storm and flood damage.
Moreover, a research professor at the University of California Santa Cruz, Michael Beck has been investigating how wetlands could be used to improve the ability of coastal communities to be resilient in times of a changing climate. One of his studies concluded that mangroves reduce global flood damage by $82 billion a year — including $13 billion in the U.S. No wonder, Florida has issued the Mangrove Preservation and Trimming Act in 1995 to protect the mangroves.
Moreover, with the passage of cyclones Irma and Matthew in the last couple of years in the region, these mangroves have proven their protective skills in the area. Mangroves both reduce storm waves and prevent future coastal erosion, hence reducing damage as much as they can.
Saltmarshes cover an even bigger area of over 13,000 square km. Unfortunately, the Australian Department of the Environment and Energy estimates that since 1950, most estuaries in south-east Australia have lost over a quarter of the saltmarsh, with some even up to 80%.
Most zones have been lost or fragmented due to urbanisation, drainage works, weed invasion, dumping, stormwater run-off, off-road vehicles, and shore protection works such as sea walls. These treats increase with the population growth in coastal zones.
Global under treath
Unfortunately, already one third of the world’s mangrove forests have been wiped out. Moreover, a 2014 UNEP (United Nations Environment Program) report said mangroves are being cleared up to five times faster than other forests.
So, however mangroves are by scientists recognised as first line defence against rising sea level, waves, storms, and flooding, they rapidly need protection. Since, for for mangroves to thrive optimally they need to be protected and/or restored, be part of a broader protective ecosystem, and have the optimal circumstances to recover and grow.
Yet, you already know that the same story goes for koral reefs, but let me tell you more about the rainforest in the next post.