Establish how biotic and abiotic factors affect the distribution of Sabellaria alveolata

S. alveolata bioconstructions result from the worms’ tube-building activity, the supply of settlers and a combination of environmental conditions.

The aim of this objective is to use combined modelling approaches to estimate habitat suitability for S. alveolata and provide modelled maps where biogenic constructions may occur, with quantitative information relative to the source/sink role of each site into the overall dynamics of S. alveolata habitats. We seek here to understand how variation in habitat quality and in physiology of the tube-builders affect the growth or decline of biogenic reefs. Habitat quality is defined as the combination of factors classified into categories such as:

-structure (temperature, salinity, flow velocity, etc.)

-meteorological (wind and wave direction and intensity etc.)

-biological productivity (chlorophyll a production)

-topography (bathymetry, slope, cover of hard vs soft-bottom, nature of sediment etc.).

The main purpose of this objective is to quantify factors best explaining S. alveolata occurrence.

We will assess bioconstructions responses to environmental changes and relate them to shape, extent and growth over the entire latitudinal gradient of S. alveolata. We will first focus on areas with fine scale hydrodynamic models (e.g. English Channel and Atlantic French coast). We will combine dynamic energy budget models to explore population responses and include them as variables. This objective will lead to predictive maps under climate change scenarios, but will also enable the hindcasting of the evolution of S. alveolata reefs using modelled environmental parameters. Ultimately, this objective may assist in marine spatial planning and identification of candidate Special Areas of Conservation (SACs) or Marine Protected Areas (MPAs).