According to the objectives proposed, the work plan has been structured in six work packages (WP). The WP1, 2 and 3 gather high-quality information to model the future of the biogeomorphic systems (WP4) and their BC services (WP5). WP6 has a transversal nature and aim the dissemination and communication of the iBESBLUE project.

WP1: Past and present-day distribution of the biogeomorphic systems of Cádiz Bay

Task 1.1 –Mapping CBNP biogeomorphic systems

Mapping is a key tool to understand and manage efficiently any ecosystem. This work package is going to focus on the study of current and past distribution of the intertidal habitat categories.

The study areas will be mapped using present-day and past aerial orthophotographs obtained from the Spanish National Plan of Aerial Orthophotography (PNOA) or from satellite images (e.g., Sentinel 2, Quickbird) when necessary. The HR-sites Will be characterized during the lifetime of the project with UAV technology.

Vegetation shifts due to changes in the ratio of salt marsh-tidal flat-seagrass areas, will be determined as an estimate of shoreline dynamics and landcover changes. We will map the habitats of interest and extract biogeomorphological indicators (e.g., areas; perimeters; proportion of vegetated versus non-vegetated/open water surface areas, by using vegetation and water indices as Normalized Difference Vegetation Index or Soil Adjusted Vegetation Index. The comparison will include total changes from 1956 until present (last available information), but also the analysis of the decadal trend. The categories to classify the maps will be generated from the combination of features defined by Habitat Directive 92/43/CEE and EUNIS (European Nature Information System) classification, following the INSPIRE European Directive (2007/2/CEE). These categories will be used as the SLAMM Land input Categories (see WP3).

WP2. Development of an accurate DEM for the intertidal area of the CBNP

Task 2.1 – CBNP intertidal DEM

High precision in elevation measurements is very important in saltmarsh and seagrass habitats because small changes (i.e. 20 cm) can represent a change in the dominant vegetation. In these habitats, the presence of vegetation is associated with the inundation frequency, elevation and connectivity of the system. Aware of the high importance of this variable, WP2 has been designed for the development of an accurate digital elevation map (DEM) of the study area.

For the HR-sites, DEMs will be developed with the use of RTK equipped UAV. Ground-control points will be measured to validate DEM accuracy. To upscale the results to the entire bay, a lower spatial resolution intertidal DEM will be developed with the waterline method (Tong et al. 2020). This last methodology will be calibrated/validated with the results from the UAV flights.

WP3: Biogeomorphic processes

This WP will focus on the characterization of the main processes involved in the functioning of the biogeomorphic habitats in Cádiz Bay (Figure 1). The selected processes include biological (primary production, biomass and its remineralization) and physical processes (erosion/sedimentation rates).

Field work will be designed in cell-units of the different habitat categories (Figure 1).

Figure 1. (left) Summary of main processes working in the functioning of intertidal biogeomorphic systems. PP: Primary production. (Right) Example of grid design for estimating processes and modelling changes in the HS-site of CBNP.

Figure 2. Field deployment overview of onae sediment trap and PIN in the horizon of Spartina maritima (left) and a SET instrument measuring local elevation changes (right).

WP4. Potential for resilience of biogeomorphic systems to Sea Level Rise

Most of the processes related with coastal habitat resilience (e.g., suspended sediment availability, sediment deposition, plant productivity or elevation) are spatial -explicit processes. Therefore, understanding them requires from spatial-explicit models. The iBESBLUE will explore the resilience of the system using the Sea Level Affecting Marshes Model (SLAMM), which simulates changes of land-use and land-cover types through time (Liao et al. 2011, Faguerazzi et al. 2020) and it is suitable for long-term and large-scale, simplified simulations (Carrasco et al., 2021).

Field data collected during the project (DEMs and derived slopes from WP2, habitat distribution maps from WP1, long- and short-term SARs from WP3) regarding past and present conditions will be used to calibrate and validate the model, respectively.

WP5: Blue carbon services

The objective of this WP will be to evaluate BC stocks in intertidal areas (saltmarsh, seagrasses, bare sediment) and BC sequestration rates in these habitats. This work package relies on the biochemical analyses and dating of the sediment cores extracted in WP3. The consequences of different scenarios of climate change on the BC sequestration in CBNP will be modelled as a function of the results in WP4.

WP6: Strategic communication and dissemination

Communication and dissemination are transversal objectives for the iBESBLUE. We believe that making the research results accessible is fundamental in times of climate change, and should cover not only dissemination to other scientists, but also transfer this knowledge to the managers of the coastal systems, as well as, transmit the importance, vulnerability and opportunities of the BC systems in an accessible format to increase awareness in general society.

Therefore, the iBESBLUE has an specific WP for this aim that focus in three target groups:

• Dissemination to scientific community
• Transference plan for policy makers/Governance and stakeholders
• Science communication to general public