Difference between revisions of "Coastal Zones"

From Dry Tropics Wiki
Jump to: navigation, search
(Threats to Coastal Zone Health)
(Threats to Coastal Zone Health)
Line 164: Line 164:
  
 
== Threats to Coastal Zone Health ==
 
== Threats to Coastal Zone Health ==
Coastal areas are extremely important and delicate [[ecosystem]]s with highly specialised flora and fauna. Plants in each part of the [[Coastal Zones | coastal zone]] have specialised adaptations and roles that are essential to the overall health of the [[ecosystem]]. Essential roles that these plant perform include:
+
Coastal areas are extremely important and delicate [[ecosystem]]s with highly specialised flora and fauna. Plants in each part of the coastal zone have specialised adaptations and roles that are essential to the overall health of the [[ecosystem]]. Essential roles that these plant perform include:
  
 
* Trapping and binding mobile sand
 
* Trapping and binding mobile sand

Revision as of 11:45, 21 October 2008

The coastal ecosystem is very complex with several very different zones, all of which are interdependent on each other. It is not possible to remove any part of the system without severely impacting on all remaining areas. Plants in this ecosystem are highly specialised, so when they are removed or destroyed there is great impact on surrounding flora, fauna, sand movement, nutrients and oxygen levels.


Coastal Zones 002.jpg


Fore Dune and Dune Crest

The fore dunes are essential barriers against extremely harsh oceanic conditions. They withstand ocean storms, extreme sun, strong winds and powerful waves. There has never been a man made equivalent of the fore dune area that has been effective in the long term. Vegetation in the dune area catches wind blown sand and binds it to the dune. Without plants to trap the sand, the sand is blown away and the dune erodes. Plants in this zone are extremely enduring with special adaptations that allow survival. They provide vital protection for fauna that live in this zone, such as crabs, and for other flora further back in the dunes. The dune crest is also subject to harsh conditions with plants in this zone prone to growing in patches to provide extra protection to themselves.


Common plants found in this zone within the Burdekin Dry Tropics include:



Beach Scrub and Hind Dunes

This area is relatively protected from the elements by the fore dunes and therefore more stable. There is more vegetation in this section, although these plants are still very hardy. Beach scrubs are vine forests growing in sand and often a denser thicket with older and larger trees. They are very valuable communities due to their high biodiversity (or number of different plant and animal species living together). Soil is still loose and sandy, but held together by the trees and shrubs. This zone is rapidly disappearing in many places due to coastal developments. Beach scrub in particular is now an endangered community, with over 70% of the original extent of beach scrub wiped out. Without this defensive hind dune zone, infrastructure has decreased protection from erosion, winds and cyclones.


Common plants found in this zone within the Burdekin Dry Tropics include:



Mangroves

Saltmarsh

Threats to Coastal Zone Health

Coastal areas are extremely important and delicate ecosystems with highly specialised flora and fauna. Plants in each part of the coastal zone have specialised adaptations and roles that are essential to the overall health of the ecosystem. Essential roles that these plant perform include:

  • Trapping and binding mobile sand
  • Providing an essential barrier from the particularly harsh ocean environment for terrestrial life
  • Preventing erosion and exotic flora and fauna species from destroying the dune.

Planting local species in residential gardens has a two fold positive effect. First it limits the competition of exotic plants or weed species, which upset the delicate plant ecology and out-compete natives. It also increases the spread of local species through birds, insects and other fauna to dunes and and surrounding coastal areas. This latter effect is especially important because without these plants, coastal areas are unprotected from natural elements and can become unstable and mobile. Erosion is arguably the biggest problem faced by coastal managers today.

There are many threats to the Burdekin Dry Tropics coastline, from obvious threats such as vehicles driving on dunes and vegetation, to more subtle threats such as the spreading of weeds. Coastal development is a complex issue which is ever on the increase. Industrial, recreational and housing developments change the physical structure of dunes and the interaction with the natural environment. These developments remove vegetation and introduce pollution and effluent to the ecosystem, thus creating erosion and increased nutrient loads.

Climate variability is a contributing factor to rising sea levels. Saltmarsh and fore dunes are particularly effected as the forefront areas of these natural systems can't evolve quickly enough to survive. With the disappearance of these ecosystems, marine species loose their nurseries and protection for breeding, and terrestrial life loses the natural barrier from the ocean. Increased levels of ultra-violet radiation due to ozone depletion also contribute to plant loss and put pressure on ecosystems. These alterations to the natural environment extent to changing the natural fire regime. Many native plants use fire as a stimulus for germination and fire intensity and timing is critical to the survival of several local species.

All of these contributing factors are putting untold pressure on our coastline which is becoming more pronounced. Legislation is slowing changing to protect this delicate ecosystem, but without appreciation of these important natural areas and action from the local community, they may become a thing of the past.