The importance of resolving coastal currents in simulations of larval dispersal
The introduction, spread and establishment of marine non-native species, facilitated by the continued expansion of global trade and transportation networks, presents one of the biggest global threats to biodiversity and ecosystem functioning. Increases in hard structures such as marine renewable energy devices or coastal defences, built partly as a response to climate change, also potentially facilitate the secondary spread of non-native species by providing stepping stones of suitable habitat for fouling organisms. Within the ECOSTRUCTURE project we are developing biophysical modelling techniques to help predict and understand the dispersal of marine organisms in the Irish Sea. However, shelf-scale biophysical models typically omit near-shore and inter-tidal features and processes, which potentially have a significant role in larval dispersal. Here, we evaluate how nearshore flows affect coastal larval spread in the Irish Sea, a semi-enclosed energetic shelf sea with considerable potential for renewable energy developments as well as with evidence of existing marine non-native communities. With a better understanding of the role of nearshore dynamics on larval transport processes, it is possible to more accurately simulate the spread of non-native species in the marine environment.
Figure. Difference in particle trajectory (released from the same point) simulated by output from high resolution (orange) and low resolution (green line) hydrodynamic models.