Bio-Inspired Designs for Conservation Gains in Hardened Freshwater Shorelines

Concrete walls and metal or vinyl sheet pilings are commonly used in freshwater systems, including lakes and rivers. Such hardened shorelines are used as a means of reclaiming land for development or as erosion control measures and are typically flat surfaces void of structural complexity. Natural systems, however, have high levels of habitat complexity that yield high volumes of surface area and interstitial space that can be used for refuge, feeding, or other important ecological functions by diverse freshwater organisms. Over the last few decades, there have been innovations in marine systems where hardened shorelines are being augmented by bio-inspired sea walls that include features (ranging from holes and crevasses to simulated mangrove prop roots) to achieve conservation gains for marine life. Freshwater biodiversity is in crisis, with habitat loss and degradation representing one of the most significant drivers of decline. Drawing on lessons learned from similar initiatives in marine environments, new pilot-stage work in freshwater systems have started investigating ways to integrate habitat complexity into hardened shorelines. These interventions offer a promising opportunity to improve conservation in landscapes that has been altered. This paper summarizes the extent of hardened shoreline use in freshwater systems and its contribution to the freshwater biodiversity crisis, presents a case study to develop, deploy, and test alternative structures (embracing learnings from the marine realm), and identifies practical considerations and research needs that must be overcome for such efforts to be widely embraced.