Ecological Effects and Coastal Landscaping
(WP 2.2)
Illustration by: Joost Fluitsma
WP 2.2 – Ecological Effects and Coastal Landscaping
To gain insight into long-term ecological effects of sand nourishments and methods to mitigate or even offset negative impacts by smart coastal landscape
Start & end date
Year 2 – year 6
Work package leader
Wageningen University
Methodology
Building on information from other WPs we (1 PhD, 1 Post-Doc) will explore how the changes in beach morphology, sediment dynamics and sediment type associated with different nourishment scenarios (with WPs 2.1, 2.3 & 2.4) will affect future habitat diversity and area, and therefore, the communities that could develop at a specific location (Reiss et al., 2015). The Post-Doc will synthesize existing data from locations differing in nourishment and management strategies to link community-composition (species, functional groups) and recovery traits to habitat characteristics from shoreface to fore-dunes and assess implications for food quality. This information will enable comparison of ecological impact of alternative coastal landscaping designs (Temmerman et al., 2016). The PhD will test and refine the relationships at the Living Lab sites. The knowledge will be used to design and implement nourishment strategies to develop a healthy, resilient and sustainable sandy coast, given accelerated SLR (WP 4).
The Post-Doc will extract relationships between beach geomorphology, sediment characteristics and beach management and benthic communities from the shoreface up to the high water line using existing data ( e.g. Janssen & Mulder, 2005; Leewis et al., 2012; Van Egmond et al., 2018; Wijsman et al., 2022) from locations differing in nourishment regimes along the Dutch coast. In a subset of sites showing contrasting composition and recovery rates of benthic community we will explore their potential cascading effect on higher trophic levels (food quality).
A similar approach will be taken for the development of terrestrial plant communities, where we will build further on recent coastal research projects (Duneforce, ReAshore) where we assessed how establishment and growth of characteristic beach plant species and associated topographic development responded to beach morphology, abiotic (salinity, soil moisture, sediment characteristics, inundation), anthropogenic (beach management, recreation) and biotic (dispersal of seeds, rhizomes) drivers (Van Puijenbroek et al., 2017abc ). The extracted relationships will be translated into development pathways to explore if and how nourishment impact on biodiversity can be mitigated or even offset by alternative coastal landscaping design.
The PhD will further test and refine the expected ecological impacts by monitoring habitat development and occupation (by benthic species and plants) at the Living Lab site from the shoreface to the fore-dunes. Benthic macrofauna will be assessed in two monitoring rounds at the beginning (eDNA only) and two years after finalizing the Living Lab site (eDNA & conventional monitoring), enabling a before and after comparison (Jeunen et al., 2019). Key species will be photographed for visualization and communication purposes (WP 3). For plant establishment we will use a germination and plant experiment to speed up colonization in selected areas designed for contrasting geomorphology and sediment characteristics. Survival of introduced seeds and rhizomes as well as natural establishment will be monitored at yearly intervals throughout the study period. To capture both geo-chemical and geo-morphological aspects of the habitats developing across the sea-land boundary we will combine conventional point-sampling (e.g. salinity, organic matter, soil moisture, elevation, sedimentation-erosion dynamics) with spatially-explicit techniques (UAV above water, multi-beam sonar below water) in cooperation with WPs 1 and 2.1.
Description of research activities
Task 2.2a Assess the impact of nourishment scenarios, sediment characteristics and beach use on the disturbance and recovery rate of key marine macrofauna and terrestrial (plant) communities across the sea-land boundary.
Task 2.2b Assess consequences of contrasting composition and recovery trajectories for cascading effect on higher trophic levels (food quality) and topographic development
Task 2.2c Explore novel monitoring techniques for more time-efficient biodiversity assessment of benthic communities.
Task 2.2d Assess the potential of offsetting species loss associated with nourishments by new habitat creation through smart landscape design and management for three regions differing in coastal geomorphology and beach use (“Voordelta” in the SW of the Netherlands, closed Holland Coast, Wadden Sea barrier island coast).
Productive interactions (co-design and co-creation)
Productive interactions will be mostly be with the other WPs 2 to understand nourishment impacts on sediment dynamics and ecology and the consequences and opportunities offered by non-native nourishment materials. In addition we will help co-design the Living Lab with WP 1 and support WP 3 with image material and guidelines for visualization and communication purposes. We will work closely together with stakeholders RWS, Stichting De Noordzee and Waardenburg Ecology regarding nourishment specifics, the use and synthesis of datasets gathered for past impact assessments and the relationship between nourishment design and ecological development pathways. Finally, scientific output from WP 2.2 will help WP 4 in designing eco-friendly nourishment strategies.
Contribution to project (impact)
The insight into long-term ecological effects of sand nourishments and methods to mitigate or offset biodiversity loss (Scientific breakthrough; Output) will inform debate and support decisions and design towards a more nature-inclusive sand nourishment strategy that aligns better with legislation goals to halt, or even reverse, biodiversity loss at national and EU levels (Outcomes). This is necessary to co-create multifunctional sand nourishment strategies for resilient dynamic coastal landscapes with high socio-economic and natural values (Societal Impact).
Key results
[Here the key results of this WP will be presented.]
Other Work packages
WP 1 – Living Lab Nourishments
WP 2.1 – Quantification of Sediment Pathways
WP 2.3 – Exploration of Non-native Sediments for Coastal Nourishments
WP 2.4 – Predictive Modeling of Coastal Nourishment Impacts
WP 3.1 – Sand Nourishment Game
WP 3.2 – Spatial Quality of Nourished Coastal Landscapes
WP 3.3 – Social Cost-Benefit Analysis
WP 4 – Sand Nourishment Strategy Development in the (inter)national context