Species specific surveys initially targeted known locations and the immediate vicinity of the target species. Recent records and records with accurate location information were prioritised for field survey effort. All attempts were made to gather precise location information from a previous observer if possible.
Botanists first visited known localities to confirm the record and to collect population and habitat data, and also to enable them to construct a more or less 'intuitive' model of potential habitat for each species. This approach ensured that further searches of other areas was targeting appropriate habitat for each species, and is recognised as an effective method of identifying potential habitat for rare plant species, often at a resolution finer than most existing digital environmental coverages utilised in species modelling (Elith et al. 1998).
A field methodology based on that which was developed and successfully utilised during the NRAC Significant Plants Project (Sheringham & Westaway 1997) was used. It is generally equivalent to, but of necessity less detailed than, the approach taken by Keith (1997) for targeted surveys during the Tasmanian CRA. Minor additions to the methodology to increase efficiency with assessing larger populations and to collect more information on all areas searched were added in accordance with techniques described by Cropper (1993). Samples of pro-formas used to collect data for this project are presented in Appendix 1.
All known records for the target species were provided to botanists, who visited these locations and conducted a search of the area. Null searches and search transects were marked on 1:25000 maps. When a population of a target species was located the area of the population was delineated, and marked on a 1:25000 topographic map. A count of the population was conducted by carrying out parallel-line searches and temporarily marking plants to avoid double counting. All individuals of small populations were counted, but where a population was too large or spread over a large area several random quadrats were used to determine average density and calculate the number of individuals in the population on the basis of total population area, taking into account gaps in the population where no individuals were present. The total population was assigned to breeding classes (vegetative, buds, flowers, fresh fruit, old fruit) and age structure classes (seedling, immature, mature, senescent). Populations were also assessed for their regeneration response to fire, and assigned one or more of eight response codes (Appendix 1). Botanists also recorded observable and potential threats based on land use and evidence of previous disturbance of the population.
Systematic data collected in a 20m x 50m plot placed within the population included environmental and structural data as well as full floristic information with cover abundances, if time allowed, or the three dominant species in each stratum. Where possible, voucher specimens of target species were collected, and are now lodged with the National Herbarium of New South Wales at the Royal Botanic Gardens, Sydney and the herbarium of the North Coast Regional Botanic Garden, Coffs Harbour.
In addition, opportunistic sightings of non-target regionally significant species were recorded. These records were generally made using a less detailed pro-forma (Appendix 2) but if the incidental record represented a population of a taxon listed on a schedule of the NSW Threatened Species Act (1995), then the same data were collected as for target taxa.
3.Results and Discussion
3.1 DATA VALIDATION
10,464 records of 251 taxa were assessed for taxonomic and spatial accuracy. 4032 records were accepted by expert review, 3122 records were quarantined by expert review and 3310 were automatically quarantined as duplicate records. 542 records collected during the current project were included in data validation and accepted for use. Of the existing imported data, about 3500 records or only about one third of all records available, were considered useable. This is understandable, given the specific nature of this project and the fact that the majority of records have been obtained for reasons other than species modelling and assessment of response to disturbance characteristics of plant populations.
3.2 SELECTING TARGET TAXA
The final list of taxa for targeted survey in the Upper and Lower North East CRA regions is presented in Table 3.1.
Note: species in bold type were not subject to targeted surveys due to time and resource constraints, and partly due to confusion over study area boundary changes during the UNE/LNE CRA.
Region: LNE = Lower North East; UNE = Upper North East.
TSC: Listing on a schedule of the NSW Threatened Species Conservation Act: E = Endangered; V = Vulnerable; X = Extinct.
ESP: Listing on a schedule of the Commonwealth Endangered Species Protection Act: E = Endangered; V = Vulnerable; X = Extinct.
FBRTD: Listing on the Forest Biota Response to Disturbance inventory of Vascular Flora of Conservation Significance of North-Eastern NSW: Codes are explained in Table 2.2 above.
ROTAP; IFA: Conservation status as coded in Briggs and Leigh (1996); Conservation status as assessed during Interim Forest Assessment workshops (V = Vulnerable; E = Endangered) and percentage of populations required to be conserved.