Abstract. Invasion by introduced species is a global threat to the natural environment, with major consequences for biodiversity, economies and societies. This paper reviews the literature documenting interactions between introduced and native bird species. Surprisingly, we found only ten cases of an introduced bird being involved in a process that threatened a population of a native bird with extinction and conclude there is little evidence that introduced birds are a major threat to avian diversity globally. The conservation priorities for managing interactions between introduced and native birds are: (1) strong, precautionary biosecurity policies and practices to discourage future introductions; (2) gaining knowledge about interspecific interactions; (3) managing threats where they affect the persistence or recovery of threatened and endemic island bird species; (4) managing the threat of hybridisation and (5) best practice, cost-effective management that defines threatening processes to avian diversity and uses adaptive management for threat abatement. Our review highlights the lack of evidence for detrimental effects of introduced birds on native avifauna and highlights the need for future work in this area.
Ecotones have been considered as unique environments, and the concepts of edge effect and ecotonal species have been widely used, especially in avian community ecology. We studied the patterns of bird densities across heath-wood edges at replicated sites in three locations in southeastern Australia. Multivariate analysis showed that the bird community in the ecotone was intermediate between the heath and wood communities, indicating that the ecotone contained a mixing of species rather than a unique bird community. ANOVA showed a modest increase in bird density at the wood side of the ecotone, which may be partly due to sampling biases rather than to some inherent habitat value in the ecotone. The outstanding pattern was that bird density and species richness in the wood habitat were twice as high as in the heath habitat. Of a total of 86 species, 31 occurred in sufficient numbers to categorize according to their habitat association (generalist, or heath or wood specialist) and their density at the ecotone (ecotone neutral, ecotone shy, or ecotone conspicuous). Three of these were habitat-generalist-ecotone-neutral. Fourteen species were ecotone neutral but were habitat specialists on either the wood (13 spp.) or the heath (1 sp.). Three species were ecotone shy. Although 11 species were ecotone conspicuous, they also occurred in either heath or wood or both. Thus, no species could be categorized as entirely ecotonal. We conclude that there is little evidence from this or other studies of avian communities to support an edge effect of increased density and species richness, and no evidence of entirely ecotonal species.
The Eastern Bristlebird Dasyornis brachypterus is a threatened passerine, endemic to southeastern Australia. It is a cryptic, ground dwelling, semi-flightless inhabitant of dense, fire-prone vegetation and is usually only detected by its calls. The disjunct distribution suggests that they were once more numerous and their population continuous from southern Queensland to western Victoria. Their decline has been documented in historic and recent times. Habitat loss, nest desertion and fire have been implicated in the decline and extinction of local populations. Strongholds for the species are Barren Grounds Nature Reserve and Bherwerre Peninsula, 100 and 150 km south of Sydney respectively. At Barren Grounds, in the absence of recent fire, there were significant increases in the population between 1992 and 1996. There was a trend of increasing Eastern Bristlebird density with increasing fire-age of habitat and average density plateauing at two birds per 5 ha, 10 years after fire. At Nadgee, a coastal Nature Reserve on the New South Wales/Victorian border, the population appears to be recovering very slowly from severe wildfires in 1972 and 1980. At the beginning of 1996 there were less than 2 000 individual Eastern Bristlebirds occupying an area of approximately 100 km2. For the management of Eastern Bristlebirds, habitat manipulation using prescribed fire should not be undertaken unless site-specific population monitoring data demonstrate that it would be beneficial. Concentrations of Eastern Bristlebirds and potential fire refuges should be protected from unplanned fire. For prescription burns, potential escape routes need to be planned for Eastern Bristlebirds. The threatened status should be changed from Vulnerable to Endangered.
Abstract. In late December 2003, a wildfire in the Jervis Bay region of New South Wales burned through an area that previously supported a large population of the endangered eastern bristlebird (Dasyornis brachypterus). The eastern bristlebird has been described as fire-sensitive, and fire is implicated in the decline of the species. The frequency of occurrence of bristlebirds was investigated in the second week after the fire in a range of sites varying in fire intensity. Bristlebirds were found in burned habitats but were less common in the sites that were more intensely burnt. Bristlebirds had been surveyed along transects in this area two months before this fire and were surveyed again 1, 9 and 13 months after the fire. Compared with prefire numbers, bristlebird numbers decreased in burnt areas after the fire and increased in unburnt areas. This pattern was evident for up to nine months after the fire, after which bristlebird numbers returned towards prefire levels in both burnt and unburnt vegetation. This is in contrast to some previous research on bristlebirds and fire. We suggest that bristlebirds avoided the fire by moving to unburnt areas and returned later when conditions were more suitable. We consider that the apparently slight impact of this fire on bristlebirds was due to the close proximity of unburnt habitat and other refuges. The response of bristlebirds and presumably other birds to fire is likely to be strongly context-dependent, so fire management may be able to be designed so as to be compatible with the conservation of local bristlebird populations.
Summary In conservation management, ensuring that the most appropriate research is conducted and results are actually put into practice is a complex and challenging process. While there are success stories, many hurdles can reduce the likelihood of appropriate research being initiated and its findings communicated and implemented. This article describes the ideal research–management cycle, summarizes the major factors that impede it and draws on the experiences of the authors to provide a series of examples of successful approaches to help keep the cycle going. We consider that the major impediments to a functioning research–management cycle relate to a lack of collaboration, poor communication, inappropriate funding and political timelines, change inertia and a lack of capacity. Although addressing structural difficulties such as matching funding timelines to those required for ecological research is a fundamental challenge, we can make incremental improvements to the way in which we operate that will improve the chances that research is both useful and used. The principles underpinning our success stories are (i) strategic development of capacity, (ii) increased breadth and depth of collaborations between researchers and managers and (iii) improved communications. Participants in the research–management cycle must seek to involve stakeholders through all project stages from project conception, to implementation, evaluation and knowledge updating. Finally, we should only see the first iteration of the research process as complete when new knowledge is applied operationally with monitoring and ongoing evaluation in place.
Summary The Eastern Bristlebird (Dasyornis brachypterus) is an endangered endemic passerine of south‐eastern Australia. The re‐establishment of extirpated populations through translocation was identified as a key action in New South Wales to address the threats to this species associated with habitat fragmentation and widespread and frequent fire. At Jervis Bay during 2003–2005, 50 birds were translocated from Bherwerre Peninsula to Beecroft Peninsula. In the Illawarra in 2008, 50 birds were translocated from Barren Grounds Nature Reserve to Cataract. At Jervis Bay, monitoring indicated that after 7 years, (i) there was no detectable impact on the source population from the removal of birds and (ii) the count at Beecroft Peninsula was 94 birds, with dispersal up to 6.3 km from the release point. In the Illawarra, (i) the source population was recovering 3 years post‐removal and (ii) the maximum count at Cataract was 15 birds after 3.5 years, including evidence of breeding, and after 3 years, the maximum dispersal was 7 km from the release point. Both translocations adhered to five key principles as follows. (i) Feasibility analysis prior to each project was favourable. (ii) For 17 pre‐stated criteria for success, 14 and 10, respectively, were met for Jervis Bay and Illawarra. (iii) Financial accountability was achieved with detailed statements showing budgets of $201k and $92k, respectively, for Jervis Bay and Illawarra. (iv) Ecological research was incorporated into both projects. (v) The results of each project are progressively being published. The re‐introduction at Jervis Bay has succeeded, and we are optimistic about the Illawarra re‐introduction.
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