Australian Terrestrial Biodiversity Assessment 2002
Paul Sattler and Colin Creighton
National Land and Water Resources Audit, 2002
ISBN 0 642 3713
Case Study
The north coast of Kangaroo Island looking east towards Cape Torrens.
Photo: P. Canty
Kangaroo Island (Kanmantoo 1) Third lowest stress class
The Kangaroo Island subregion comprises Kangaroo Island itself and several smaller satellite islands. Kangaroo Island is the most important area for nature conservation in the higher rainfall areas of South Australia. It retains the highest proportion of uncleared natural vegetation of the agricultural districts, but more importantly, rabbits and foxes have not been introduced to the island.
Condition and trend
Eight of the region's ecosystems are either listed as vulnerable or endangered at the State level. All are declining in condition.
Four nationally threatened fauna species have been recorded on Kangaroo Island.
- The Glossy Black-cockatoo (Calyptorhynchus lathami halmaturinus) has a recovery plan in place and is gradually increasing.
- A recovery plan has been completed for the Kangaroo Island Dunnart (Sminthopsis aitkeni).
- Many of the known populations of both the Dunnart and the Southern Brown Bandicoot (Isoodon obesulus obesulus) are within reserves. While the trend for both is considered static, populations are low and recovery is likely to require significant management.
- The Heath Rat (Pseudomys shortridgei) is only known on Kangaroo Island from a single 1967 record and no information is available on its current status.
Fourteen nationally threatened plant species are known to occur on Kangaroo Island. While all have been recorded within at least one protected area, most are poorly conserved with the largest populations occurring on roadsides in the extensively cleared agricultural areas of the eastern end of the island. Most are declining in condition and in need of management to ensure recovery.
Threatening processes
The nationally threatened flora species and Statelisted ecosystems face common threatening processes:
- road maintenance activities;
- fire frequency;
- weed invasion;
- limited remaining extent, making populations extremely vulnerable to catastrophe such as bushfire or disease;
- grazing and, in the case of some eucalypt communities, koala browsing;
- dryland salinity; and
- the root rot fungus Phytophthora cinnamomi.
Mammal species are threatened by:
- habitat fragmentation;
- predation by cats and dogs; and
- inappropriate fire regimes.
The Glossy Black-cockatoo is threatened by:
- nest hollow shortage and competition;
- low breeding success;
- nest predation;
- limited food supply (drooping sheoaks);
- fire, particularly where it reduces available nest hollows or drooping sheoaks; and
- suppression of drooping sheoak regeneration by stock grazing.
Special case
Koalas (Phascolarctos cinereus) were introduced to Flinders Chase National Park in the 1920's. An assessment of Koala numbers and tree condition in 1994 estimated the total population on the island to be between 3000 and 5000 individuals. More recent estimates are much higher. If Koala populations are not limited, over-population will not only continue to kill trees and degrade riparian habitats, but could also result in a food shortage for the Koalas, leading to starvation.
A management program was developed that focussed on sterilisation, translocation, habitat protection and restoration, and community education. Thus far the monitoring of tree health has indicated a general improvement in tree canopy condition in some areas where Koalas have been removed. Better integration of the annual monitoring, modelling and management programs is required if amelioration of the impacts of Koala browsing at an island-wide scale is to occur.
Methods
The approach taken to develop biodiversity strategies in the Kangaroo Island subregion involved consideration of the following:
- A comprehensive, adequate and representative reserve assessment. This process identified four environmental associations that are less than 7% conserved. Within those environmental associations with more than 10% of area conserved, a further four ecosystems and two threatened plant species were identified as inadequately represented within the reserve system.
- Identification of a possible candidate areas of these priorities for addition to the existing formal reserve system.
- Identification of species and/or ecosystems suitable for multi-species recovery programs, such as nationally threatened plants of the Amberley Environmental Association.
- Development of recovery actions.
- Identification of existing and possible integrated natural resource management actions that maximise conservation of the most threatened species and ecosystems.
Management responses
Key management responses include:
- maintenance of Bushcare Grants Scheme to provide incentives for landholders to conduct on-ground works;
- re-introduction of IBIS Award Scheme to encourage ecologically sustainable production;
- whole-of-catchment response to salinity management;
- maintenance of existing on-ground works aimed at arresting decline of native vegetation;
- encouraging further initiatives such as Heritage Agreements and fencing grants to protect remnant native vegetation;
- retention of viable threatened plant populations on roadsides;
- revegetation of corridors to link remnants of threatened ecosystems;
- coordinated weed control, particularly in areas of remnant native vegetation and coordinated feral animal control;
- maintenance of threat abatement program for Phytophthora cinnamomi;
- development of agricultural industry codes of practice that limit impact to flora and fauna; and
- recognising the Island's special values and support nomination as a biosphere reserve.
Before you download
Most publications are downloadable as PDF files. Adobe Acrobat Reader is required to view PDF files.
If you are unable to access a publication, please contact us to organise a suitable alternative format.
Key
Links to an another web site
Opens a pop-up window