Our Biodiversity Vulnerabilities
A number of vulnerabilities to biodiversity in the Northern Agricultural Region have been identified and these are shown below.
Clearing of Natural Areas
Fragmentation of the landscape occurs as a result of removal of large areas of native vegetation, leaving behind small and unconnected remnant bushland. Fragmentation also occurs as a result of the construction of large linear infrastructure such as railways and pipelines and is exacerbated by the degradation of road reserves. Clearing of natural areas, which includes habitat destruction, leads to a loss in the diversity of both flora and fauna species and communities.
Alterations to hydrological regime
The extensive removal of native vegetation also results in alterations to hydrological regimes including increased flash flooding and groundwater rise. In some areas, inland drainage has been installed to mitigate the problem and saline discharge may pose a threat to remnant vegetation and aquatic systems.
Recreation in natural areas also results in impacts on plants and animals. Increased and often uncontrolled access to fragile environments such as coastal areas and other natural areas from tourists, locals and visitors often leads to increased rubbish and disturbance to habitat, flora and fauna, as well as the introduction and transfer of exotic pest and disease species. These impacts have the potential to significantly affect the health, diversity and range of plant and animal species and communities.
Further loss of vegetation and biodiversity of flora and fauna may occur as a result of the accidental or commercial introduction of diseases, weeds, pests and feral animals, which compete for food, water, soil and land. The Federal Government has reported twenty weed species of national significance (WoNS) and the Biosecurity and Agriculture Management Act 2007 (BAM Act) maintains a list of Declared Pests within Western Australia. Introduced animals cause adverse environmental impacts because ecological constraints on them, such as predation, competition from other species, diseases and parasites, are often absent. Some introduced animals also carry disease and can affect human health, as well as act as pests to agricultural activity. A number of introduced fauna have been reported within the NAR, the commonly reported feral animals include: deer, wild dogs, goat, red fox, cat, rabbit and pig.
Within the NAR, a number of fungal diseases have been identified including Armillaria lutebubalina (the Honey Fungus) and various species of the Phytophthora genus (dieback). These fungal diseases are particularly damaging to native vegetation and kill wide range of species in Western Australia.
Altered Fire Regime
Although many native flora and fauna have evolved several strategies in the event of a fire, Europeans have altered the natural fire regimes considerably by altering their frequency and intensity. Not only do uncontrolled high intensity fires endanger human lives but remnant vegetation is destroyed. The occurrence of controlled fires for the purpose of reducing fuel load availability to reduce the intensity of an uncontrolled fire, can potentially impact on existing vegetation and fauna within the area.
While the full extent of the impact of climate change on biodiversity is not yet known, several basic assumptions can be made. The first of these is that global mean temperatures will rise. This may result in a dryer climate for the NAR and extended periods of drought. The second is that storm events may increase in intensity and that tropical storms may occur at lower latitudes than present. The implications for NAR ecosystems may include increased erosion and episodic flooding. The final assumption is that sea levels will rise. The impact of sea level rise on inter-tidal species is likely to be severe and the loss of coastal habit will not only affect those species that reside there on a permanent basis but also those that visit for breeding, procreation and migratory reasons (Steffen et al. 2009).