The threats to mangroves
Degradation and destruction of mangrove communities in the Redland may result from a number of threats.
Direct threats
Clearing
In the past the major sources of mangrove forest degradation, has been the clearing, draining and reclamation of these intertidal marine environments.
This direct destruction of mangrove environments has resulted from:
- the perception that mangroves are a breeding site for mosquitoes and biting midges, and therefore needed to be destroyed
- the demand for a variety of land uses to take their place including:
- farmland
- marina developments
- residential subdivisions
- industrial development
- sewage treatment ponds
- rubbish Dumps
- roads
- sportsfield.
Indirect threats
Catchment alterations (for mangroves in the riverine environment)
- Alteration of freshwater flows means salinity levels may become too high or too low for mangroves to stay healthy.
- Alteration of nutrient inputs means the health of mangroves can deteriorate when exposed to high levels of nutrients eg. from fertiliser inputs.
- Upstream erosion may cause large amounts of sediment to build up around mangroves, suffocating them by covering their pneumataphores (mangroves use these special roots, which stick out of the mud, to breathe).
Trampling through uncontrolled access by humans and by stock (eg. cattle)
- this causes ‘sinkage’ and destruction of pneumataphores.