Other initial observations reveal general patterns of distribution of the two mangroves. Firstly, grey mangrove mostly grows closer toward the low tide mark than river mangrove. Grey mangrove also appears more frequently toward the mouth of the estuary while river mangrove is more dominant further upstream. Various biotic characteristics, such as annual rainfall, seasonal variations in rainfall, temperature extremes, wind exposure, soil type/texture, topography, pH, sunlight and availability of tourists, to name a few, influence the diversity, distribution and populations of species within the mangrove ecosystem.
Since European settlement, human activities have degraded many wetland environments around Australia, and the Inamorata Intertribal wetland IS no exception. Threats and impacts to wetlands include: * Alteration of natural water regimes – This can be caused by activities such as artificial drainage, the extraction of groundwater, the construction of dams and weirs and the loss of vegetation. Plants and animals that inhabit wetlands re often dependent on a particular water regime, and may be affected by changes in water levels and inundation. K Loss of Vegetation – The vegetation that occurs around the wetlands is an important component of the ecosystem.
The vegetation assists in maintain regular wetland water regimes, provides habitat and food for fauna, protects against salinity and erosion, provides soil stability, filters pollutants and provides natural beauty while helping to maintain a healthy wetland. Loss of vegetation fall result in the loss of these values. Salivation and excessive inundation – Salivation and excessive inundation are widespread issues in agricultural areas and are generally caused by the replacement of perennial deep rooted native vegetation with shallow rooted introduced annual crops and pasture. ( not so prevalent in our study area, but a common threat to many other wetlands) * Introduction of invasive species – This includes the introduction of weeds and feral animals into the wetland environment. Weeds invade and compete with native plant species for resources.
Feral animals are known for their seductive impact on wetland areas and can disrupt the intricate food chains that exist within the ecosystem. * Water Pollution – Contamination off water body can be caused by various activities, including the use of chemicals (fertilizers and pesticides) in the catchments of wetlands, the drainage of pollutants and toxic materials into wetlands, and accidental chemical/oil spills. Some contaminating substances can be harmful to wildlife and can greatly reduce the water quality of the wetland.
Arbitration/housing development – The impact of humans building close to the shore of the river as led to the destruction of kilometers of mangroves within the wetlands in order for them to have more desirable views. Patches of mangroves have been cleared and evidence of them re-growing can be seen. It is illegal to pull out the mangroves in the study area. Natural processes such as fire, floods, cyclones and drought are all naturally occurring processes that have the potential to damage wetland environments. Fire can remove or change habitat available for wildlife around wetlands.