The Vertebrate Fauna of Kamay Botany Bay National Park

Kamay Botany Bay National Park (KBBNP) is an iconic Sydney reserve, both for its cultural and historical value to all Australians and its spectacular scenery and clear vantage points to the open sea. The reserve comprises two separate sections on the northern and the southern headlands of Botany Bay, the La Perouse Precinct and Kurnell Precinct respectively. Both precincts are largely isolated from other contiguous native vegetation cover by intense urban and industrial landscapes, yet retain some of the best remaining examples of the native vegetation that once stretched along the Sydney coastline. Despite high levels of visitation and a long standing historical and scientific interest in the park, the vertebrate fauna values of KBBNP have remained incompletely described.

In 2010, as part of the Biodiversity Survey Priorities Program, OEH undertook a project to address this information shortfall. The project included compilation and review of fexisting auna information, new systematic and targeted survey work, and production of a report to provide an inventory and prioritisation of fauna species, habitats and threats. A profile was created for each threatened species to summarise current distribution and status in the reserve, while habitat profiles described the fauna typical of each of the main habitats. Threatening processes were identified and ranked, with management recommendations targeted towards the highest priority fauna species.

The project found that 190 native terrestrial vertebrate fauna species are residents in or visitors to the reserve, in addition to 14 introduced species. Eighteen species listed as threatened under the Threatened Species Conservation Act 1995 use the reserve to varying degrees. KBBNP contributes significantly to the regional conservation of nine of these species. Being four times the size of the La Perouse Precinct, the Kurnell Precinct currently supports a richer assemblage of fauna, with 182 native species compared to 118 in La Perouse. These levels of diversity are comparable to other reserves in the Sydney urban area, such as Sydney Harbour National Park.

The swamp sedgelands, which primarily occur in the Kurnell Precinct, are considered the highest priority fauna habitat in KBBNP as they support two of the most significant fauna species: wallum froglet and grass owl. Though it is hard to see, the tinkling call of the tiny brown wallum froglet can be heard on cool humid nights from most of the sedgelands that are nestled in the sand dunes at the southern end of the park. The sighting of a single grass owl, also in the swamp sedgelands of the Kurnell Precinct, was the most exciting finding of the field surveys. This owl is very rare in the Sydney Basin, with only three other confirmed records. The significance of this sighting was enhanced by the detection of several 'pellets' at a roost site. These pellets are regurgitated by the owl to remove non-digestible components of prey such as bone and hair, and on analysis were found to almost exclusively contain black rat and house mouse remains, providing a rare insight into the diet of this owl in an urban reserve. The swamp sedgelands also provide habitat for several regionally significant species including southern emu-wren, tawny-crowned honeyeater, buff-banded rail, Lewin's rail, pheasant coucal and golden-headed cisticola.

Arguably, the most characteristic vegetation of both precincts is the heathland that stretches from the exposed sandstone clifftops to the deep sand dunes. These also have high significance to fauna, not least by the provision of foraging resources for the grey-headed flying-fox. Many people visit KBBNP to spot shorebirds along the ocean coastline, where the intertidal rock platforms and small beaches provide another type of priority fauna habitat. Threatened or declining species that occur along the shoreline include sooty oystercatcher, pied oystercatcher, Australian fur-seal, New Zealand fur-seal and infrequently little tern, double-banded plover, Pacific golden plover, Lesser sand-plover and several additional migratory birds. The significance of the swamp forest that grows around the picnic areas and park facilities at Commemoration Flat in the Kurnell Precinct often goes unnoticed by park visitors. Though the nature and extent of this habitat is the most highly modified in the park, the swamp mahogany trees still provide foraging resources for several nectarivorous parrots and bats including the endangered swift parrot, and hence are also considered to be priority fauna habitat.

Various fauna species of KBBNP have responded differently to the pressures of being in a relatively small urban reserve. In the La Perouse Precinct, threatened eastern bentwing-bats show their adaptability by regularly roosting in the man made gun emplacements. In contrast, many species are known or suspected to have been lost or declined from the reserve. Most strikingly, only one native ground mammal species remains, and even that occurs in low numbers, although what constituted the mammal assemblage in the 1700s is unclear. Several bird species have ceased to occur, including white-fronted chat, eastern bristlebird, painted button-quail and brown thornbill, amongst others. Losses from the La Perouse Precinct have been more numerous, for example green and golden bell frog, small-eyed snake and blackish blind-snake.

The greatest threats to the ongoing survival of priority fauna species within KBBNP at this time are predation by the fox and cat, changes to local hydrology, fire, weed invasion, establishment of feral deer and public disturbance. Threats to fauna diversity as a whole include invasion of the cane toad and the lack of connectivity to other reserves, meaning that the two precincts effectively operate as two islands. Addressing the latter threat will require promotion of habitat linkages between the Kurnell Precinct and Towra Point Nature Reserve and between the La Perouse Precinct and the new reserve at Malabar Headland.

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Page last updated: 17 March 2014