Modelling the potential distribution of the eelgrass Zostera marina at local and regional scale in Ireland

Eelgrass, Zostera marina L., the most widely distributed seagrass in the northern hemisphere, plays a key role in the coastal zone in terms of high productivity, stimulation of biodiversity, protection of the coastline, carbon... [ view full abstract ]

Eelgrass, Zostera marina L., the most widely distributed seagrass in the northern hemisphere, plays a key role in the coastal zone in terms of high productivity, stimulation of biodiversity, protection of the coastline, carbon storage and nutrient retention. However, despite these key effects on marine ecosystems, its conservation status and distribution in Ireland is not clear, partly because of inaccessibility of potential eelgrass habitats. It is therefore likely that actual distribution of seagrass along the coast of Ireland is larger than currently reported in the literature. Here, ecological niche models (ENMs) were used to calculate habitat suitability at local and regional scale, and moreover, to identify the relative importance of different factors determining the presence of eelgrass communities at these scales. To develop species distribution models, sediment, bathymetry, slope, current velocity and water temperature at different depths were used as key factors determining distribution. The predicted areas of Zostera marina habitats were compared with an eelgrass distribution map obtained by using satellite derived images. Our models have predicted the potential range of the Irish eelgrass which will be verified by sampling. As eelgrass populations are under threat globally, an accurate distribution map of eelgrass in Ireland will be critical to define adequate future conservation policies. This project therefore constitutes an essential study to contribute to current efforts in seagrass monitoring and management across Europe.