Kangaroo Island’s natural resource assets can be sustainably managed only by effectively managing the threatening processes that cause the degradation or decline of these natural resources. The Island is fortunate that rabbits and foxes were never successfully established here. Fortunately too as an Island we can prevent new arrivals and reintroductions of pests (weeds, feral animals, diseases, problem native animals and marine pests).
Nevertheless, a suite of processes threatens the natural resources of Kangaroo Island:
1.
Fragmentation of native vegetation to isolated remnants resulting in:
- reduction of habitat
- loss of plant and animal populations
- decreases in genetic diversity of plant and animal populations
- increased susceptibility of species to catastrophic events
- degradation due to increased edge effects such as weed invasion
- reduced ability of species to migrate
- altered hydrological regimes and associated threats such as salinity
- changes to the nutrient cycle
- modifications to predator-prey relationships
- variations to pollination and seed dispersal mechanisms
- changes to the composition and abundances of species altering species competition
- alterations to temperature, wind and radiation regimes
- competition for resources
- prevention of recruitment
- alteration of geomorphological processes
- modification of the nutrient content of soil
- changes to hydrological cycles
- loss of primary production
- variations to fire regimes
- changes in the abundance of indigenous fauna
3. Introduction of pathogens such as Phytophthora species
4. Inappropriate fire regimes resulting in:
- changes to the pattern, seasonality and intensity of fires
- fires of increased magnitude
- loss of species through lack of recruitment or suitable habitat
- loss of primary production and built assets
- feral honeybees affecting the pollination and subsequent seed production of native plant species and competition with native pollinators
- feral cats affecting native animals through predation and primary production through the spread of diseases such as Sarcosporidosis and Toxoplasmosis
- feral goats affecting native vegetation through browsing, grazing and trampling and as a consequence the resources available to native browsers/grazers
- feral pigs affecting native vegetation, native animals and primary production through consumption, ploughing and the spread of Phytophthora species
- feral deer affecting native vegetation through grazing, ringbarking, creating paths and primary production through grazing and spreading Phytophthora species and other diseases of domestic stock including Johnes disease
6. Introduction of problem native animals such as:
- koalas affecting native vegetation and causing the extinction of local populations of plant species through over-browsing
- little corellas affecting native bird species such as Glossy Black-Cockatoos through competition for nest hollows and primary production through grazing
- primary production through grazing pressure and competition with stock for water
- native vegetation through intense grazing pressure preventing successful recruitment of species
8. Increased nutrient input to Nepean Bay destroying its
seagrass meadows as algae smother the seagrasses
9. Disturbance to
intertidal reefs from increased human visitation and illegal removal of organisms living on the reef
- soil acidity, which affects approximately 200,000 ha
- dryland salinity, causing an estimated cost of at least $1,000,000 per year to the Island (excludes costs associated with water quality and biodiversity decline)
- waterlogging and flooding, which is dependent on seasonal conditions and can impact approximately 100,000 ha
- water repellant sands, affecting some 46,000 ha; new management techniques being promoted by the Board provide an almost permanent solution
- soil structure and organic mater decline, which could potentially affect almost all soils on the Island
- wind and water erosion which is currently a low risk to the Island that could dramatically increase with climate change.