Abstract
Worldwide, coastal ecosystems are rapidly degrading in quality and extent. While novel restoration designs include facilitation to enhance restoration success in stressful environments, they typically focus on a single life-stage, even though many organisms go through multiple life-stages accompanied by different bottlenecks. A new approach – life cycle informed restoration – was designed to ameliorate multiple bottlenecks throughout an organism's life cycle. It has successfully been tested on a small scale to facilitate intertidal bivalve reef formation in the Netherlands and Florida. Yet, it remains unknown whether this approach can be scaled to ecosystem-relevant scales. To test whether life cycle informed restoration is upscalable, we conducted a large-scale restoration experiment using blue mussel reefs as a model system. In our experiment, we used biodegradable structures to temporarily facilitate mussel reef formation by providing early-life settlement substrates, and subsequently, reduce post-settlement predation on an intertidal flat in the Wadden Sea, the Netherlands. The structures were placed in 10 × 20 m plots, mimicking bands found in natural mussel beds, spread out across 650 m, and were followed for two years. Our results show that the structures enhance mussel biomass (0.7 ± 0.2 kg DW m−2), as mussels were absent in bare plots. However, biomass varied within plots; in intact structures it was 60 times higher (1.2 ± 0.2 kg DW m−2) than in those that became buried (0.02 ± 0.009 kg DW m−2). Next to burial, 18–46% of the structures were lost due to technical failure, especially during winters at this exposed site. We show that the life cycle informed restoration principle works, but we encountered technical challenges due to larger scale processes (e.g. sedimentation). Furthermore, environmental information is essential for site selection, and for restoration, the functioning of such structures should be tested under extreme conditions before upscaling.
Highlights
Coastal ecosystems provide many important ecological and societal services, including shore protection, the provision of food and biodi versity (Grabowski et al, 2005; Coen et al, 2007; van der Zee et al, 2012)
We found 0.7 ± 0.2 kg DW m− 2 (4500 ± 1000 individuals m− 2) mussels in the plots with establishment structures and 0 ± 0 kg DW m− 2 in the unmodified controls (Fig. 2, χ2 = 12.886, p < 0.001)
Over the course of two growing seasons, mussel biomass continued to increase in intact establishment structures, while mussels remained absent in controls (Fig. 2B)
Summary
Coastal ecosystems provide many important ecological and societal services, including shore protection, the provision of food and biodi versity (Grabowski et al, 2005; Coen et al, 2007; van der Zee et al, 2012). Epibenthic bivalve reefs, salt marshes, mangroves and seagrasses have strongly declined by 35–85% (Gedan et al, 2009; Waycott et al, 2009; Beck et al, 2011) To counteract this decline, restoration attempts aim to assist the recovery of coastal ecosystems and their ecological functions (Bayraktarov et al, 2016; Duarte et al, 2020; Saunders et al, 2020). These attempts often fail because positive species interactions that are typically important in harsh coastal systems (e.g. selffacilitation that leads to improved growing conditions, such as sedi mentation or reduction of wave energy), are not included in restoration designs or are very expensive (Silliman et al, 2015; Bayraktarov et al, 2016; Saunders et al, 2020; Temmink et al, 2020)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
