High genetic diversity in a clonal relict Alexgeorgea nitens (Restionaceae): implications for ecological restoration

Abstract

The importance of genetic issues associated with the sourcing of propagules is increasingly recognised for successful ecological restoration. A consideration of life history traits has contributed to ‘best-guess’ scenarios on the appropriate location and desirable properties of local provenance source populations, but these can lack precision. For clonal species, population genetic structure and variation will depend on the balance between the extent and growth rate of asexual clones, sexual reproduction, pollen dispersal, and subsequent seed dispersal and recruitment. We assessed patterns of population genetic structure and variation for Alexgeorgea nitens (Nees) L. Johnston & B. Briggs (Restionaceae), a dioecious, clonal, perennial species, with novel life history traits. Our results show high levels of genetic diversity within populations, and surprisingly low levels of population differentiation (ΦST = 0.17). We suggest that the high genetic diversity observed within these populations reflects extensive pollen dispersal and successful seeding (sexual reproduction) and recruitment events, even though direct observations of seedling recruitment are rare. In this case, a ‘best-guess’ propagule-sourcing scenario based on life-history traits that appear to limit dispersal capability does not predict the extent of high local genetic diversity and weak population genetic structure in A. nitens.

Inbreeding and outbreeding depression in Stylidium hispidum: implications for mixing seed sources for ecological restoration

“…This division corresponded to the greatest cross distance for hybrid comparisons, and predicted two regions or zones for seed transfer among experimental locations. Nested AMOVA results for S. hispidum reflect moderate levels of genetic subdivision detected in other endemic, outcrossing plant species from the region (Bussell et al 2006;Krauss and He 2006;Sinclair et al 2008Sinclair et al , 2010.…”

An ecological genetic delineation of local seed‐source provenance for ecological restoration

“…The relatively weak genetic similarity between populations in Bold Park and Kings Park has been observed in many other species (e.g., Krauss and He ; Sinclair and Hobbs ; Sinclair et al. ), and is likely to be driven by substrate and climatic differences. Indeed, the ordination of climate data shows this well, where Bold Park clusters with populations to the north, and Kings Park clusters with populations to the south.…”

“…Climate variables were annual, January and July averages for each of mean rainfall, potential evapotranspiration, solar radiation, maximum and minimum temperatures and were obtained from the Australian Bureau of Rural Sciences Natural Resources Data Library and extrapolated to location coordinates with Diva geographic information system (GIS). Sinclair et al 2010), and is likely to be driven by substrate and climatic differences. Indeed, the ordination of climate data shows this well, where Bold Park clusters with populations to the north, and Kings Park clusters with populations to the south.…”

Contribution of genetics to ecological restoration

“…In contrast, Alexgeorgea nitens (a dioecious, clonal, perennial species) displayed high levels of genetic diversity within populations, again unexpected for a clonal species with limited seed dispersal (Sinclair et al . ). These studies exemplify one of the advantages of using surveys of genetic diversity in restoration to establish appropriate genetic targets for focal taxa.…”