Degree Name

Doctor of Philosophy


Department of Biological Sciences


Maintaining biodiversity is a basic theme in conservation in Australia and around the world. Biodiversity is defined to encompass the variation and abundance of species, genes, populations and ecosystems/habitats and is fundamental to maintaining many ecological processes. Human activities have caused loss of habitat and fragmentation of the remaining habitat, ultimately reducing biodiversity. Isolated patches of remnant bushland often form the last refuges for threatened species.

Attempts to conserve biodiversity have taken many directions including, in most countries, the use of a reserve system. However, it is unlikely that a reserve system can, by itself, achieve conservation and therefore other strategies must be employed. Legislation has taken a prominent role in the protection of biodiversity, mostly focusing on threatened species. The nature of such legislation in N.S.W. has varied over the last century, ultimately leading to the current Threatened Species Conservation Act 1995 (NSW) (TSCA) which is tightly intertwined with planning legislation, through the Environmental Planning and Assessment Act 1979 (NSW) (EPAA). This thesis focuses on the ability of the TSCA and EPAA Part 4, as they relate to development applications made to local councils, to achieve effective conservation.

There were four main components to the study. First, I critically reviewed the relevant parts of the legislation to assess the nature of the demands on scientific knowledge made by the legislation, second, I use two threatened species: Tetratheca glandulosa and Darwinia biflora as case studies to assess how local councils applied the TSCA and the EP AA. Thirdly, I conducted ecological field studies of the pollination ecology and reproductive success of T. glandulosa and D. biflora: to determine how more complete scientific knowledge might alter decision-making. Finally, I used the integration of the scientific studies and the review of the legislation to identify ways in which legislation, and it application by decision-makers, could be altered so as to improve conservation outcomes.

Many different interest groups have seen the TSCA (in its interrelationship with development assessment and control under the EPAA Part 4 ), as a fundamental step towards threatened species conservation and therefore biodiversity conservation. In fact, the TSCA is a mixture of proactive and reactive approaches to conservation. It has four main mechanisms; (i) listing, (ii) the so-called "eight part test" (determining if an action has a significant impact upon a listed species in order to determine whether an SIS and the concurrence of NPWS is required), (iii) the species impact statement (SIS), and (iv) the recovery plan. Listing and recovery planning occur under the TSCA and eight part tests, SISs and concurrence by National Parks and Wildlife Service are required under the EPAA. The legislation has attracted many criticisms, a primary one being that it offers inadequate protection to biodiversity and threatened species, because it assumes that comprehensive scientific evidence exists or can readily be obtained.

Four case studies were used to examine the existing framework, as a basis for proposing an ideal framework. First, a housing subdivision at Aquatic Drive, Allambie Heights was the centre of three decisions by the Land and Environment Court. At one stage, Tetratheca glandulosa was mis-identified. This case study highlighted the fact that scientific uncertainty can surround even the simple question of whether a species occurs on a site, and the importance of completing field surveys at the appropriate time of year. Second, a subdivision at Green Road, Glenhaven demonstrated how an amelioration process can be built into the eight-part test to ensure a smooth passage for a development application, despite the fact that the amelioration was based on questioned theory and lacked any empirical evidence. Third, the role of the NPWS · and the acceptance of scientific uncertainty were highlighted in the proposed council development at Camarvon Drive, Frenches Forest. Illustrating the responsibilities of council in deciding whether a development application should be approved. Fourth, a comprehensive debate between experts on the existence of a possible seed bank characterises the case study based around a proposed housing development at Grosvenor Street, North W ahroonga. This illustrates the potential ecological importance of a component of a plant's life-history that can not be readily detected.

Ecological data were gathered to test the appropriateness of decisions on the two species: Tetratheca glandulosa and Darwinia bifiora, given the original paucity of knowledge. These species occur in a range of sites: some large, protected populations in National Parks and some small, more isolated, disturbed populations in land that has been developed or was the subject of a development application. I examined pollination biology, pollination success and viable seed stores. To examine the pollination biology of both species a bagging and cross-pollination experiment was carried out. The fitness of the resulting seed was inferred from seed weight and length. Potential pollinators were identified using a trapping regime and potential clonality of Tetratheca glandulosa was tested using Amplified Fragment Length Polymorphisms (AFLP) markers. The pollination success for T. glandulosa and D. bifiora at different sites was examined using flowering and fruiting densities, pollinator behaviour and pollen removal rates. The viable seed store was assessed by looking for seeds in the soil seed bank, estimating the annual input into the seed store and testing for seed germination and dormancy.

Tetratheca glandulosa displayed a strong preference for out-crossed pollen, while Darwinia bifiora exhibited self-compatibility, but with a preference for out-crossed pollen. No difference was found in seed weight or length for either species across sites or across pollination treatments. No pollinators were identified for either species. Genetic analysis using AFLP markers suggested that T. glandulosa is potentially clonal but results were inconclusive.

Fragmentation of habitats is assumed to be detrimental to the life cycles of many species through edge effects, invasion of non-native species, disease and interruptions to gene flow. Such impacts have led to what is known as a "pollinator crisis scenario", which results in the loss of pollinator guilds or communities through habitat alteration, invasive species and pesticides. Individuals of Tetratheca glandulosa in the large National Park population produced more flowers but less fruit than those in small, disturbed sites. There was no fruit set or pollen removal from flowers in the two smaller, isolated sites. In contrast, flower production and fruit set, pollinator visitation and pollen removal did not vary significantly among sites for D. bifiora. Seed banks of both T. glandulosa and D. biflora showed very little or no seed in the soil. Seeds were easy to germinate (little dormancy), suggesting short-lived seed banks. Therefore, neither of these species could depend on the seed bank for survival through a sequence of disturbances. Maintaining reproductive success will require the pollination processes are sustained.

I conclude that there are significant problems with the present approach taken in the legislation and its implementation. These include: (i) lack of ecological knowledge, (ii) inadequate use of ecological knowledge during the decision-making process and (iii) the lack of a formal pathway for incorporating the precautionary principle and adaptive management. I propose a more appropriate model, which includes (i) incorporation into decision-making processes of more basic survey work and ecological experiments, (ii) incorporation of recovery plans into Local Environmental Plans and Regional Environmental Plans, (iii) integration of recovery planning into the SIS process, and (iv) the introduction of a peer review system to reduce inconsistencies in the interpretation of scientific knowledge and theory.

The ideal decision-making framework proposed consists of six elements; (1) the formal production of a development application, (2) consultation with local councils and independent scientists, (3) an accredited peer review system, ( 4) formal and informal roles for the N.S.W. National Parks Wildlife Service, (5) the use of development conditions, development modifications and adaptive management and ( 6) appeal to the Land and Environment Court.