Rapid genetic delineation of provenance for plant community restoration.
Abstract
Best practice in native plant community restoration and/or revegetation recognizes the importance of using material of local provenance. At the practical level, various guidelines exist but these have limitations. The challenge is to deliver accurate provenance information rapidly to the restoration industry. We demonstrate a novel approach to the rapid delineation of genetic provenance by utilizing minimal sampling, the power and efficiency of the AFLP DNA fingerprinting technique and a multivariate spatial autocorrelation analysis for four species (Dryandra lindleyana, Lomandra hermaphrodita, Bossiaea ornata and Lechenaultia biloba) with high priority for minesite revegetation in south-west Western Australia. A significantly positive genetic correlation was found between individuals in the smallest distance class for three species. Correlograms then stabilized, with no significant genetic correlation between individuals at any other distance class. A local genetic provenance distance was here defined as the distance where the correlogram goes from significant to non-significant, which was approximately 26 km, 20 km and 20 km for these three species. In contrast, for the fourth species, no significant genetic correlation was seen at any distance class, suggesting a very broad genetic provenance (up to 100 km), although the possibility of significant structure below the smallest distance class used here (20 km) cannot be dismissed. Whilst spatial autocorrelation has identified significant spatial genetic structure for 3 of 4 species assessed, a robust delineation of provenance distance, or patch size, is problematic because it is dependent on properties of sampling and analysis such as the scale of sampling and the choice of distance class size, especially when sample sizes are small. Synthesis and applications. The determination of seed collection zones for revegetation projects is a complex problem. We demonstrate a new approach for the rapid delivery of genetic provenance delineation for native plant community restoration, and provide recommendations for seed collection zones for each of four species. This approach can be applied to other species and other areas. We discuss the limitations of the approach, and conclude that further research is required to assess an appropriate minimal sampling strategy that leads to a more robust delineation of provenance distance. We also note that revegetation programmes provide an opportunity to experimentally assess the biological significance of the local provenance as defined, through an assessment of the relative performance of plants sourced from within and beyond defined provenances.