6 Beach wrack monitoring

Monitoring, understanding and accompanying the impact of global changes on coastal marine biodiversity and shorelines are crucial for the conservation of biodiversity. Beach wrack - seaweed deposition- have important roles for conservation (rare, vulnerable species) and coastal ecosystem functions (trophic, erosion mitigation). Their composition and their quantity are expected to change under global warming and eutrophication, seaweed exploitation. And these composition changes are likely to result in changes in beach wrack management.

We hypothesized that surveying strand line (beach wrack) could i) inform on spatial and temporal changes of proximal marine ecosystems (seaweed biomass, community composition) and ii) allow to better understand the impact of global changes on (socio)-ecosystem relationships (sand beaches).

We co-construct a citizen monitoring program of beach wrack ecosystem (Plages Vivantes, Chanel-Atlantic French coast) in collaboration with several stakeholders (NGOs) and built an interdisciplinary research team. We will analyze the standardized data collected at large scale (>150 sites) using a functional approach (species characteristics, community approach..). Our aims are

i) to assess to what extend and in what conditions the monitoring of beach wrack produces relevant indicators of marine proximal ecosystems,

ii) to document and hierarchize the effects of anthropogenic and climatic drivers on beach wrack composition (key element of coastal ecosystem / indicator of marine proximal ecosystems),

iii) to develop and implement relevant indicators of the states and trends of the studied biodiversity facing different pressures to inform public, stakeholders and policy makers.

Beach wrack website