S60 ECOLOGICAL MANAGEMENT & RESTORATION VOL 4 SUPPLEMENT FEBRUARY 2003 Introduction D elineation of genomic provenance boundaries of two well-distributed arid tropical native grass species from the north of Western Australia was undertaken to establish propagule harvest zones and protocols to ensure replacement of locally diverse populations after mining. Main- tenance of the local genetic provenance provides the greatest opportunity for suc- cessful establishment of plants, because local genotypes are presumed to be more suited to prevailing conditions and have been shown to out-compete introduced genotypes. For example, in translocation studies of Nassella pulchra, local geno- types grew at twice the rate with greater survival than non-local genotypes (Knapp & Dyer 1998). Restoration of local geno- types also facilitates the integration of the restored area with the surrounding matrix of vegetation (Fletcher et al. 1994) and minimizes perturbations to the indigenous breeding system (Haig et al. 1990; Rossetto et al. 1995). Restoration of genetically typed material (genetic restoration) Restoration of common species should follow similar protocols to those used in conservation programmes for rare species (Coates & van Leeuwen 1996), which aim to retain the ebb and flow of local genome dynamics (Mistretta 1994). This necessi- tates delineation of natural genomic boundaries to allow selection of propag- ules, which maintain the integrity of the local provenance (Rossetto et al. 1995) and remove the potential for out-breeding depression and weed hybridization (Montalvo & Ellstrand 2001). The data also determine the number of individuals from which propagules must be harvested to maintain natural diversity (von Perger et al. 1994; Rossetto et al. 1995). Molecular genetic differentiation in grass taxa has identified that individual clones can encompass a broad range of spatial scales. Single clones dominate entire climatic regions (Rice & Mack 1991), while changes between clones can occur within a few metres (Hamrick & Allard 1972). Phenotypic variation may also occur within a genotype grown under A molecular approach to provenance delineation for the restoration of hummock grasslands (Triodia spp.) in arid-tropical Australia By Grant Wells, Grace Zawko, Maurizio Rossetto and Kingsley Dixon Grant Wells, Grace Zawko and Kingsley Dixon are Restoration/Conservation Scientists with the Botanic Gardens and Parks Authority (Kings Park and Botanic Gardens West Perth, Western Australia 6005, Australia. Grant Wells is the corresponding author.Tel: +61 8 9480 3623; email: grantw@kpbg.wa.gov.au). Maurizio Ros- setto is the Conservation Ecologist with Plant Sci- ences, Royal Botanic Gardens Sydney (Mrs Macquaries Road, Sydney, NSW 2000, Australia. Tel: +61 2 9231 8337; email: Maurizio. Rossetto@rbgsyd.nsw.gov.au). The project was funded by Argyle Diamonds Pty Ltd as part of a study to restore endemic hummock grasses to post-mine sites and supported the authors research into the conservation genetics of Aus- tralian flora. Summary Studies were undertaken to develop genetic principles for the restoration of spinifex grasses (Triodia spp.) at the Argyle Diamond Mines in northern Australia. The study used random amplified polymorphic DNA (RAPD) DNA markers to provide a molec- ular delineation of provenance boundaries for two species Curly Spinifex (Triodia bitextura) and Triodia bynoei and to provide measures which ensure replacement of local genetic diversity. Within-population diversity measures (0.44 ± 0.03 T. bitextura and 0.32 ± 0.04 T. bynoei) and the proportion of diversity attributed to between-population differences (≈ 12%) by analysis of molecular variance (AMOVA) indicate extensive out-crossing in these seeder species. As such, both species should be restored using seed-based methods to maintain natural diversity. Significant groups of populations (P < 0.05) identified by AMOVA correspond directly to clustering of populations in a dendogram drawn using UPGMA, indi- cating significant provenances in both species. For T. bitextura, a significant genotypic vari- ation identified at 60 km from mine populations was not evident at 30 km. Seed for restoration at the mine should, therefore, be harvested from within 30 km of the area to be restored to ensure maintenance of the local provenance. Two T. bynoei populations located 2 km apart were found to represent a single genotype, all other populations were identified as separate genotypes. The majority of the isolated T. bynoei populations, therefore, rep- resent distinct provenances. For both species, in excess of 80% of the measured species diversity occurred in just 20 individuals. As restoration of these grasses will necessitate harvesting seed from thousands of plants the species capacity for evolutionary change should be maintained. With continuing improvements in the effectiveness of molecular genetics technology, the assessment of provenance boundaries through the use of genetic markers is becoming a realistic option for the development of more genetically represen- tative sourcing of genotypes in plant restoration programmes. Key words provenance, random amplified polymorphic DNA, restoration, spinifex, Triodia.