The world’s oceans and the impressive biodiversity they contain are a vital part of our planet. They offer essential ecosystem services that are critical to human well-being, such as providing food and water, regulating the Earth’s climate, and supporting tourism and recreation.
Oceans are also home to two powerful ecosystems that can be key allies in risk management, particularly for coastal areas: mangroves and coral reefs. Mangroves are trees and shrubs that grow in the coastal intertidal zone. They have a complex system of roots that help them withstand the rise and fall of tides, filter salt and provide food and shelter for aquatic organisms. Coral reefs, often called the rainforests of the sea, are underwater ecosystems that constitute one of the most diverse habitats in the world.
The IDB is committed to the protection, conservation, management, and sustainable use of biodiversity, natural resources, and ecosystem services. Ecosystem services can be important for many types of public and private sector investments that are underpinned by biodiversity such as water, health, rural development, and tourism.
In celebration of World Ocean Day, here are three reasons why mangroves and coral reefs, through the ecosystem services they provide, can be critical to increasing resilience and managing risks related to disasters and climate change.
1. They provide regulating ecosystem services, such as carbon sequestration and protection from erosion, flooding and sea level rise
Coral reefs and mangroves both serve as a first line of defense to protect coastal communities from incoming waves and rising seas, which constitute a pressing risk for millions of people around the world.
Coral reefs serve as a natural breakwater, dissipating as much as 97 percent of incident wave energy. Their hydrodynamic performance is comparable to low-crested structures used in coastal protection, reducing the vulnerability of shorelines to erosion and flooding.
Mangroves can also greatly reduce the impact of coastal erosion and flooding, particularly coming from wave action and tidal surges. Their dense root system slows down water flow, enhances sedimentation and reduces erosion, while their roots, trunk and canopy reduce the force of oncoming wind and waves. Mangroves also contribute to increasing the soil volume by trapping sediment, binding particles and depositing organic matter, which over time can help them keep up with rising sea levels.
Moreover, mangroves can have a big impact on climate, as they are among the most carbon-dense ecosystems in the world. They cycle carbon quickly and store it in the low-oxygen soil, which, if left undisturbed, can act as a long-term carbon sink.
2. They provide supporting, provisioning and cultural ecosystem services that benefit coastal communities
Mangroves and coral reefs can also reduce the vulnerability of coastal communities and contribute to their well-being by providing them with ecosystem services that can improve their livelihoods and sustain their economies.
Mangroves and coral reefs act as fish nurseries and provide grounds for many other marine organisms to live in and breed, increasing the availability of food for local communities. They can also be a source of derivatives for medicinal purposes, support timber production and provide freshwater. In addition, they support local economies by being a major source of recreation and tourism-related activities. By protecting these ocean ecosystems, we are also protecting the livelihoods of the communities that are dependent on their related services.
3. They are sustainable alternatives to traditional infrastructure solutions
Nature-based solutions constitute an affordable, sustainable option to improve resilience and mitigate impacts from natural disasters and climate change. Both mangroves and coral reefs can be less costly to maintain than gray infrastructure alternatives, with the added value that they adapt to the changing environment, leave no negative footprint and provide other beneficial ecosystem services, as mentioned before.
Investing in their protection and restoration is therefore a wise and sustainable adaptive solution, whether it is to replace or to boost other green and gray solutions to provide optimal risk reduction. In turn, mangroves and coral reefs will support food security, manage the impacts of climate change, reduce the risks of natural disasters, and provide general well-being to the many coastal communities that depend on them.
For more information on how the IDB protects ecosystem services in its projects, check out this online course on biodiversity and the management of living natural resources (available in Spanish).