Question 28 (20 marks)
‘An ecosystem at risk is both vulnerable and resilient to natural stress and human induced modifications.’ Discuss this statement
For many years wetlands were seen as only a mosquito infested area. Nowadays they are highly valued ecosystems that are being protected for future generations of wildlife, and also people. A wetland is an area of land that is temporarily or permanently inundated. Sydney’s Bicentennial Park is home to 58ha of intertidal wetlands. Sydney Bicentennial Park is located within Homebush Bay (33 51' S, 151 33' E) and is approximately 12 kilometres west of Sydney’s CBD. The intertidal wetland has formed along the southern edge of the Parramatta River. The 58 ha intertidal wetland is made up of 40 ha of mangrove forest, 10 ha of open, shallow water- the waterbird refuge and 8 ha of salt marsh. The Intertidal wetlands of Homebush Bay are vulnerable to many natural stress e.g. high salinity levels and high tide and human modifications such as bund walls. The Intertidal wetlands though are resilient to this stress through adaptations and as well as induced human strain through modern knowledge and conservation programs. Mangroves normally grow in the inter-tidal areas, with loose, soft sedimentary soil along the coast. The soil has an unstable substratum, a rather high salinity level and lacks breathability for oxygen intake. Living in such an adverse condition, mangroves have their unique ways to adapt and grow.
In order to become resilient towards natural stress intertidal wetlands survive through physiological adaptations, mangroves are able to live in harsh saline environments. The mangroves have the ability to excrete salt; these mangroves can complete this process through the many glands which are found on the leaves, where tiny white flecks of salt are frequently visible. Some species such as the Grey Mangrove can also tolerate the storage of large amounts of salt in their leaves