Genetics and species distribution modelling of Solanum johnsonianum (Solanaceae) reveal impacts of brigalow land clearing on this endemic species

Abstract

Australia is one of the centres of diversity for Solanum and many species are found in the arid zone with a concentration in the Brigalow belt. This region has been significantly impacted by land clearing and Brigalow is now an endangered vegetation type. Recent gas pipeline developments have led to further impacts to endangered species within the region necessitating offset and translocation activities. Solanum johnsonianum was impacted by pipeline construction despite little knowledge of its ecology or genetics to guide translocation or restoration. This study conducted field surveys, habitat modelling, and genetic analysis in order to increase understanding of S. johnsonianum. The species has moderate to low genetic diversity across its localised geographic range. The populations are not inbred, with some exhibiting heterozygote excess. The populations that are located close to the pipeline were among those with the highest genetic diversity. Population size varies among populations and was not correlated with genetic diversity. Evidence of clonal spread was found in most populations however they also produce viable seeds and most plants are productively active. The results indicate that care should be taken to maintain provenance and that it is recommended to follow guidelines which limit mixing of plants from different populations.