In the face of the challenges presented by climate change, urbanization, and environmental degradation, there is an increasing recognition of the significance of nature-based solutions (NBS). Harnessing the inherent resilience of ecosystems, nature-based solutions offer a holistic approach to addressing pressing global issues, providing sustainable alternatives that blend seamlessly with the natural world. From urban green spaces that enhance air quality to innovative water management strategies inspired by nature’s principles, the potential of these solutions is vast.
Some Examples of NBS
Oyster reef restoration is an interesting example of NBS. An oyster reef is a type of underwater habitat created by a collection of oysters that have attached themselves to a hard substrate, such as rocks or the shells of other oysters. Oyster reefs provide essential ecological services, such as water filtration, shoreline stabilization, and habitat creation, contributing to improved water quality, erosion control, and enhanced biodiversity in marine ecosystems. As suggested by Grabowski et al. (2012), oyster reefs, acting as a natural buffer, automatically adjust to sea level rise, making them a more resilient option for addressing coastal erosion and storm surges compared to hard-engineered solutions.
Over the past century, there has been a significant decline in both the size and health of oyster reefs worldwide. The global depletion of oyster reefs primarily results from factors such as over-harvesting, disease, and compromised water quality (Gilby et al., 2018). Oyster reef restoration is a conservation effort aimed at revitalizing and enhancing these reefs. These restoration projects strategically deploy both natural and artificial substrates, such as recycled oyster shells or biodegradable materials, to create conducive environments for oyster reef development (Howie and Bishop, 2021).
Mangrove restoration echoes yet another example of NBS in action. Mangroves serve as a natural buffer, providing coastal protection against storms and erosion. The dense root system of mangroves helps stabilize the soil and prevent erosion, while the above-ground vegetation can absorb and dissipate wave energy. Additionally, mangroves can trap sediment and organic matter, aiding in land elevation and reducing the risk of flooding. Beyond their protective role, mangroves contribute significantly to biodiversity, providing essential habitats for various marine species. Moreover, they play a crucial role in carbon sequestration, mitigating the impacts of climate change. According to Alongi (2012), the carbon stored in mangrove forests can remain locked away for up to a century, making them an important long-term carbon sink.
Mangrove restoration projects often entail the planting of native mangrove species, leveraging their innate capacity to adapt to diverse coastal conditions. Such restoration efforts prove effective in reversing mangrove loss. According to Hagger et al. (2022), the global rate of net mangrove loss decreased from 2.74% in 1996–2007 to 1.58% in 2007–2016, indicating a positive trend in the reduction of net loss over time.
Rain gardens exemplify a nature-based solution designed to address urban stormwater runoff and promote sustainable water management. Integrating seamlessly into urban landscapes, these purposefully crafted gardens leverage the innate capabilities of vegetation and soil to mitigate the impact of impervious surfaces. Serving as both aesthetically pleasing green spaces and functional stormwater management tools, rain gardens absorb and filter rainwater, thereby reducing the flow of pollutants into waterways. The native plants within the rain gardens enhance biodiversity, while the natural filtration capabilities of the soil contribute to improved water quality.
Autixier et al. (2014) explores the use of rain gardens as a potential solution to reduce the volume of runoff and address the combined sewer overflows (CSOs) problem.
CSO is a form of water pollution that occurs when a combined sewer system, designed to handle both stormwater runoff and wastewater, is overwhelmed during heavy rainfall or snowmelt. CSOs are a concern because exceeding capacity, the system discharges untreated stormwater and wastewater directly into nearby water bodies, releasing harmful pollutants like bacteria and viruses. CSOs are particularly problematic in urban areas with aging infrastructure and extensive impervious surfaces.
The research findings highlight the potential of rain gardens to effectively reduce runoff volume and the volume, peak flow rate, and duration of CSOs. The effectiveness diminishes with increased rainfall depths and the percentage of impervious areas drained to the rain garden. However, it is important to note that rain gardens may not entirely prevent CSOs in all situations. While they can assist, treating CSOs remains the most appropriate method when complete prevention is not possible, especially near drinking water sources. Additionally, rain gardens may increase the accumulation of contaminants in the sewer system, particularly during dry weather. Balancing stormwater management goals with the protection of water sources can pose challenges, necessitating continuous adaptive efforts.
To be continued in Part 2.
References:
Alongi, D. M. (2012). Carbon sequestration in mangrove forests. Carbon Management, 3(3), 313-322. https://doi.org/10.4155/cmt.12.20
Autixier, L., Mailhot, A., Bolduc, S., Madoux-Humery, A.-S., Galarneau, M., Prévost, M., & Dorner, S. (2014). Evaluating rain gardens as a method to reduce the impact of sewer overflows in sources of drinking water. Science of the Total Environment, 499, 238–247.
Gilby, B. L., Olds, A. D., Peterson, C. H., et al. (2018). Maximizing the benefits of oyster reef restoration for finfish and their fisheries. Fish and Fisheries, 19, 931–947. https://doi.org/10.1111/faf.12301
Grabowski, J., Brumbaugh, R., Conrad, R., Keeler, A., Opaluch, J., Peterson, C., Piehler, M., Powers, S., Smyth, A. (2012). Economic valuation of ecosystem services provided by oyster reefs. BioScience, 62(10), 900–909.
Hagger, V., Worthington, T. A., Lovelock, C. E., et al. (2022). Drivers of global mangrove loss and gain in social-ecological systems. Nature Communications, 13, 6373. https://doi.org/10.1038/s41467-022-33962-x
Howie, A. H., & Bishop, M. J. (2021). Contemporary Oyster Reef Restoration: Responding to a Changing World. Frontiers in Ecology and Evolution, 9, 689915. https://doi.org/10.3389/fevo.2021.689915
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