Intertidal Wetlands - Human Impacts
Humans can impact on ecosystems both positively and negatively
Positive
Humans can maximise the area of healthy, functioning intertidal wetlands by minimising their impacts and by developing management strategies that protect, and where possible rehabilitate these ecosystems at risk. The following are positive ways of trying to protect or rehabilitate intertidal wetlands.
Exclusion – Those responsible for the management of wetland areas often facilitate public access to a small, designated area while restricting access to other areas. Provision of defined boardwalks and walkways is a management strategy used to restrict access to vulnerable areas, as is the issuing of permits whilst visiting Towra Point Nature Reserve.
Education – In the past, wetlands were regarded as waste-lands. Education campaigns have helped to change public perceptions and foster public support for the wetlands. Due to their location in the catchment area, education programs need to teach about total catchment management programs. Educational programs include guided tours for the general public, school visits, media liaison, information centres, conference presentations, interpretive signage, publications and facts sheets. Staff should also include education officers.
Action – too little is known about the intertidal wetland system to successfully reinstate all natural conditions. Management plans focus on the rehabilitation of the site and the removal of human-induced stresses. For example, fox and rabbit baiting, removal of weeds (at Weedy Pond).
Design – Design interventions have proved successful in minimising sources of natural stress. At Towra Point Beach, for example, there is a sandbag wall to help prevent salt water from leaking into the fresh-water Towra Lagoon.
Legislation – Legislation and regulations are used to protect Towra Point Wetlands. Conventions that Australia has signed in regard to Towra Point Wetlands are the Ramsar Convention, the Japan Australia Migratory Bird Agreement (JAMBA) and the China Australia Migratory Bird Agreement (CAMBA). Legislation that Australia and New South Wales has passed in regard to Towra Point Wetlands are the Wetlands Policy (federal govt.), the New South Wales Wetlands Management Policy (state govt. 1996) and the State and Environmental Planning Policy 14 on Coastal Wetlands.
Negative
Changed wind patterns due to high-rise near some wetland areas e.g. Bicentennial Park.
Alteration of water flows through construction of roads, dams and recla.
Removal of resources for urban and industrial land uses. These also increase turbidity and toxins in the water supplied to mangroves. (The removal can also result in changed energy flows and nutrient cycles, affecting food chains for both sedentary and migratory fauna).
Replacement of wetland areas for parks, playing fields or pasture.
Destruction of sea grasses in areas adjoining wetlands can affect energy flows and nutrient cycles as species levels will be affected.
Introduction of exotic species e.g. foxes, rabbits, sheep, cattle, pigs. – change energy flows and nutrient cycles. Birds are particularly affected, for example the Little Tern.
Indirect influences from adjacent sites e.g. weed infestation (lantana – Towra Point) – carried into the wetlands by horses from the nearby stables.
Trampling – from illegal access
Threat of oil spills - Kurnell refinery near Towra Point
Recreational horse-riding on the Reserve and unsupervised recreational use of the Reserve (eg. dog walking)
Boating - disturbs wildlife in the park, and creates pollution.
Fishing - kills fish, which affects the food chains operating within the Reserve.
Erosion of Towra Beach due to wave refraction from the Sydney Airport runway which causes the freshwater Towra Point Lagoon to become saline .
Fragmentation of the Reserve by private land ownership
Bay development in general, including the Sydney Airport runway and the oil refinery. There have also been concerns that the recently announced desalinisation plant will impact negatively on the Reserve.
Illegal rubbish dumping has occurred both in the Reserve and near the entrance. In late 2004, a large amount of dumped asbestos was discovered.
Positive
Humans can maximise the area of healthy, functioning intertidal wetlands by minimising their impacts and by developing management strategies that protect, and where possible rehabilitate these ecosystems at risk. The following are positive ways of trying to protect or rehabilitate intertidal wetlands.
Exclusion – Those responsible for the management of wetland areas often facilitate public access to a small, designated area while restricting access to other areas. Provision of defined boardwalks and walkways is a management strategy used to restrict access to vulnerable areas, as is the issuing of permits whilst visiting Towra Point Nature Reserve.
Education – In the past, wetlands were regarded as waste-lands. Education campaigns have helped to change public perceptions and foster public support for the wetlands. Due to their location in the catchment area, education programs need to teach about total catchment management programs. Educational programs include guided tours for the general public, school visits, media liaison, information centres, conference presentations, interpretive signage, publications and facts sheets. Staff should also include education officers.
Action – too little is known about the intertidal wetland system to successfully reinstate all natural conditions. Management plans focus on the rehabilitation of the site and the removal of human-induced stresses. For example, fox and rabbit baiting, removal of weeds (at Weedy Pond).
Design – Design interventions have proved successful in minimising sources of natural stress. At Towra Point Beach, for example, there is a sandbag wall to help prevent salt water from leaking into the fresh-water Towra Lagoon.
Legislation – Legislation and regulations are used to protect Towra Point Wetlands. Conventions that Australia has signed in regard to Towra Point Wetlands are the Ramsar Convention, the Japan Australia Migratory Bird Agreement (JAMBA) and the China Australia Migratory Bird Agreement (CAMBA). Legislation that Australia and New South Wales has passed in regard to Towra Point Wetlands are the Wetlands Policy (federal govt.), the New South Wales Wetlands Management Policy (state govt. 1996) and the State and Environmental Planning Policy 14 on Coastal Wetlands.
Negative
Changed wind patterns due to high-rise near some wetland areas e.g. Bicentennial Park.
Alteration of water flows through construction of roads, dams and recla.
Removal of resources for urban and industrial land uses. These also increase turbidity and toxins in the water supplied to mangroves. (The removal can also result in changed energy flows and nutrient cycles, affecting food chains for both sedentary and migratory fauna).
Replacement of wetland areas for parks, playing fields or pasture.
Destruction of sea grasses in areas adjoining wetlands can affect energy flows and nutrient cycles as species levels will be affected.
Introduction of exotic species e.g. foxes, rabbits, sheep, cattle, pigs. – change energy flows and nutrient cycles. Birds are particularly affected, for example the Little Tern.
Indirect influences from adjacent sites e.g. weed infestation (lantana – Towra Point) – carried into the wetlands by horses from the nearby stables.
Trampling – from illegal access
Threat of oil spills - Kurnell refinery near Towra Point
Recreational horse-riding on the Reserve and unsupervised recreational use of the Reserve (eg. dog walking)
Boating - disturbs wildlife in the park, and creates pollution.
Fishing - kills fish, which affects the food chains operating within the Reserve.
Erosion of Towra Beach due to wave refraction from the Sydney Airport runway which causes the freshwater Towra Point Lagoon to become saline .
Fragmentation of the Reserve by private land ownership
Bay development in general, including the Sydney Airport runway and the oil refinery. There have also been concerns that the recently announced desalinisation plant will impact negatively on the Reserve.
Illegal rubbish dumping has occurred both in the Reserve and near the entrance. In late 2004, a large amount of dumped asbestos was discovered.
Websites, articles and resources
NSW treasurer defends Sydney airport expansion. Read more...
Sharks cry poor, turn developer. Read more...
Towra Point Wetlands win Grey Globe Award at Ramsar Convention. Read more...
Sharks cry poor, turn developer. Read more...
Towra Point Wetlands win Grey Globe Award at Ramsar Convention. Read more...
Consider: What will Intertidal Wetlands, and Towra Point specifically, be like in the future?
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