Artificial lighting technologies to support aquatic plants in rivers which are shaded by bridges and culverts.
Abstract
Aquatic plant communities are important components of river ecosystems, providing food sources and functional habitats through the provision of refuge and spawning substrate for animals including fish and macroinvertebrates. Types of urban infrastructure including bridges and culverts present a major challenge to rivers; for example, the shading effects of these structures can exclude aquatic and wetland plants, degrade and fragment habitats and inhibit the movement of aquatic and riparian species in rivers. Few studies have investigated the potential to reconnect riverine habitats through artificial lighting technologies. In this study, a 12-month controlled laboratory trial was undertaken to investigate the potential for using artificial lighting to support aquatic plants shaded by urban infrastructure. Two artificial lighting scenarios were compared to a natural light (control) scenario to determine the potential for supporting eight aquatic plant species common in UK rivers. Overall, growth rates, flower numbers and biomass values were higher for all species under the natural light scenario. However, the artificial lighting scenarios also enabled selected plants to grow and survive over the trial period with variable success in line with shade tolerance, suggesting that it is feasible to grow aquatic plants under urban infrastructure using artificial lighting. This study provides a basis of understanding on how to design an artificial lighting strategy that can support a community of aquatic plants; however, further study and in river trials are required to optimise such as system.