Mangroves on Cape York – the kidneys of the coast.
Words Sandra Lloyd | Photo Tropical North Queensland
Australia has 40 species of mangroves which cover around one fifth of our coastline, about 12,000 square kilometres. Cape York has all 40 of Australian species. Only Indonesia and Brazil have more species than Australia.
Mangroves are tropical trees that thrive in conditions most timber could never tolerate - salty, coastal waters, and the interminable ebb and flow of the tide. Mangrove roots extract oxygen with lenticels - pores that provide a direct exchange of gases between internal plant tissues and the atmosphere. Some species of mangrove have the lenticels on their prop, or stilt roots, aerial roots that arise from the trunk, penetrate the soil and support the plant. Others have them on their trunks or have pneumatophores (finger-like projections that grow up from the organic ooze of the water’s edge).
Mangroves play a major role in protecting the Great Barrier Reef by filtering pollutants, trapping sediments and providing a nursery habitat for fisheries.
In recognition of their importance, environmental research has been carried out to find out more about the health and condition of mangrove ecosystems in the northern section of the Great Barrier Reef.
The Eastern Cape York Shoreline Environmental Surveys from Cairns to Cape York monitored the character and condition of shoreline habitats and estuaries in north east Cape York. TropWATER, Centre for Tropical Water and Aquatic Ecosystem Research at JCU partnered with local Indigenous custodians to conduct aerial surveys and field investigations and mapping to assess the status of mangrove ecosystems, evaluate and monitor the condition and identify the drivers of change.
The survey covered a distance of nearly 1,500 km of the Australian mainland east coast of Cape York Peninsula from just north of Cairns to the tip of Cape York, representing around a quarter of the Great Barrier Reef Marine Park mainland shoreline.
The study found Cape York’s mangroves are under threat from climate change (rising sea levels, cyclones and storm damage and shoreline erosion), feral animals, and local land management practices.
The study outlines key local and national approaches to protect Cape York mangroves.
There are a range of common local management responses across many of the Cape York zones including improved management of vehicles, cattle and feral animals. Nationally, the study recommends the establishment of a climate change policy.
Mangroves matter - from storing carbon and protecting shorelines to nurturing fish populations and improving the quality of water heading to the Reef – and need to be protected.