Flora and Fauna values in lower north east were assessed against national estate criteria A.1, A.2, A.3, B.1 and D.1 (Appendix A).
Localised natural flora and fauna values
Sub-Criterion A.1: Importance in the evolution of Australia’s natural history
Assessment for values under this sub-criterion involved the identification of places where the present distribution and ecology of flora and fauna of lower north-eastern NSW reflect the influence of past evolutionary, climatic and environmental processes. These included places important for:
Endemic species provide an important insight into the process of evolution of flora and fauna (Sub-criterion A1). Heatwole (1987) noted two processes by which endemism could occur. The first is where a species becomes extinct over the bulk of its range except for small refugia. The second is a long period of isolation leading to the evolutionary divergence of species from a common ancestor (eg Gondwanic species in Australia). In some cases, biogeographic determinants such as the influence of terrestrial and oceanic climatic influences, soils and localised topographic variation may be the main controlling factors in the development of endemism. In other cases the role of climatic refugia in speciation during periods of climate change are important.
For the purposes of the current study, endemic species were regarded as those species with at least 75% of their distribution range confined to Upper and Lower North-Eastern NSW. The complex environment of northern NSW presents a diversity of habitats for endemic species. For example, Osborne (1991) postulated that the dry forests of the Timbara and Mann rivers and the Gibraltar granite forests may present barriers to movement for some bird species associated with wet forests of the Washpool area. Several authors have also commented on the importance of rainforest remnants in the region as centres for endemism. Monteith and Todd Davies (1991) in a study of invertebrate diversity in Queensland rainforests observed a high level of endemism between discrete rainforest areas. Main (1991) notes that even small isolates of rainforest in the landscape are significant for rainforest trapdoor spiders, which reach their greatest diversity in North-Eastern NSW. Heatwole (1987) summarised the findings of Kikkawa et al (1979) who studied the relationship of Australian heathlands with their fauna. Heath endemism was generally associated with specialised species more or less restricted to heathland because of speciation, the presence of specific habitat no longer available elsewhere or species isolated phylogenetically and geographically after heath retreated in past ages.
Workshops were used to identify fauna species with endemic distributions to north NSW to provide a species list. Data was derived from surveys conducted for the comprehensive regional assessment and from the NSW NPWS wildlife atlas. 92 fauna species were identified as being endemic. Literature reviews were also carried out to supplement the workshop responses. For flora, the literature review conducted as part of the flora workshop was used to provide a species list. Data was derived from the validated flora data-set used for comprehensive regional assessments. 227 flora species were identified as being endemic.
Point location information for all identified species was plotted respectively for flora and fauna on a one kilometre square grid. An analysis was done which searched for all records of endemic species within a two kilometre radius around each grid cell. The resultant analysis showed concentrations of endemic species, for flora and fauna respectively, across the landscape. This methodology was used because the analysis could be extended south of the Hunter River. It was compared to the work done by NSW NPWS on endemics for Lower North-East using the same methodology as was used for Upper North-East and covered the important areas delineated by experts.
4.1.2 Establishing the threshold
Experts agreed that all areas shown in the non-target JANIS analysis of centres of endemism done by NPWS were above threshold. The methodology used covers these areas but extends the analysis south of the Hunter River.
The Centres of Endemism identified as areas of indicative national estate significance are shown on Map 6. Each area depicted represents foci for endemic species using best available information to the lower north-east comprehensive regional assessment, and all areas identified are above the threshold level warranting national estate listing.
Some of the major localities delineated for endemic species were the Dorrigo plateau and the Macleay gorges including the Carrai plateau, Werrikimbe National Park, Dingo and Bulga State Forests, Barrington Tops, Chichester State Forest, and the Wallis Lake area including Wallingat State Forest. The endemic concentrations around Olney State Forest, Ourimbah State Forest and Brisbane Waters National Park are attributed to the influence of the endemic species of the Sydney Basin. The areas that were identified include several areas already listed on the Register of the National Estate including Barrington Tops, Woko, Myall Lakes, Crowdy Bay, Werrikimbe, Oxley Wild Rivers and New England National Parks.
Approximately 29% of the total area identified as centres of floristic endemism occurs in national park or nature reserve and 48% of the total area is on State Forest (Table 8).
TABLE 8: Land Tenure of indicative national estate centres of endemism