WAMSI 2 - Dredging Node - Project 5.2 - Genetic variability of seagrass in NW Australia

The aims of this study for the WAMSI Dredging Science Program were:

1. To establish fundamental knowledge on the genetic diversity of seagrass meadows; and if this varies among sites and with different environmental conditions, particularly clear and turbid water;
2. To understand the gene flow among populations; and
3. To inform the design of mesocosm and laboratory experiments on seagrass resilience.

This study was the first of its kind to examine the patterns of genetic diversity in seagrasses in the Pilbara region of WA. Three species were assessed: Halophila ovalis (6 populations), Halodule uninervis (8 populations) and Thalassia hemprichii (3 populations) at a range of spatial scales, within a meadow (centimetres−metres), among meadows at a local scale (2−60 km) and among meadows at a regional scale (up to 500 km). Due to the varied distribution of species we could not sample all species across the same spatial scale and range of environments, so we designed a nested approach, with sites replicated at a distance of 2−5 km, and then different species at varied larger spatial scales.