Measuring connectivity in the ocean
Managing multiple uses of a marine environment requires detailed knowledge of the ecosystem and its interactions.
Information about how far animals and plants travel in their lifetime can help inform decisions like where to put marine reserves and fishing zones. Information about how strongly different places are connected with each other can also tell environmental managers about an ecosystem's vulnerability to far-off disturbances.
Measurement of lifetime movement in wild organisms is extremely difficult, especially in the ocean, and has not been attempted for Kimberley wildlife.
Using DNA to track movements
When organisms move from one place to another they carry a record of their origins in their unique DNA fingerprints.
We partnered with other research institutions, traditional owners, and indigenous rangers to take advantage of this, to gain insights into the distances travelled by marine animals and plants in the Kimberley.
We used new genomic techniques ('SNP genotyping') to record detailed DNA fingerprints from a selection of Kimberley marine animals and plants. From these we estimated how far those organisms typically moved.
Together we collected 5009 DNA samples from seven plant and animals species from 157 sites across the Kimberley as well as from neighbouring regions as far away as Shark Bay and the Northern Territory.
Improved understanding of ecological connectivity
We found that each species exhibited a unique movement pattern, most likely because each has different capacity to swim or float during their important larval or seed dispersal phase. However, some general movement patterns also emerged.
Habitat-forming organisms, like corals and seagrass, tended to travel tens of kilometres or less in our study region. In contrast, the two fish species, and the mollusc we investigated travelled much further - up to hundreds of kilometres. However, the regional differences in the strength and complexity of ocean currents can complicate the general trends of these species.
In some places barriers to movement were evident, whereas other places seemed to facilitate movement. We anticipate that these first insights into the scale of movements in marine organisms from the Kimberley will provide a useful foundation for future environmental planning and assessment in this region. This information can support how to determine the ideal size and placement of marine protected areas and the identification of fishery stocks.