Genetic variability within seagrass of the north west of Western Australia: Report of Theme 5 - Project 5.2 prepared for the Dredging Science Node

Abstract

The response of seagrass species to on-going pressures such as dredging can be strongly influenced by their ability to adapt to, resist or recover from these pressures. The ability of species to adapt to a pressure, over generations, is influenced by the amount of genetic variation in a population: greater genetic diversity can enhance resistance and higher levels of gene flow between populations can enhance the rate of recovery following complete habitat loss. As seagrass are clonal plants, genetic diversity in a meadow is dependent on both the number of unique clones within the meadow, and distribution of this variation within and among meadows. Understanding the genetic diversity of seagrass meadows can provide important fundamental knowledge for the prediction of dredging impacts, by providing insights into the likelihood of recovery and the processes that may drive that recovery (vegetative regrowth, seed bank recruitment or immigration of recruits). It can also inform management, for example by providing insights into relative vulnerability to pressures, sources of recruitment populations and the importance of maintaining seed banks. However, for most seagrasses and in most parts of the world, extremely little is known about the genetic diversity and connectivity of populations..