Nature’s Defense: Using Mangroves and Coral Reefs to Combat Flooding and Protect Biodiversity

Mangrove trees (Source: Shutterstock)

February 27, 2025  •  ZACH PANLILIO

Flooding has impacted the lives of many–damaging properties and threatening lives as a disaster formulated by environmental degradation. As many people suffer from the destruction caused by flooding, many overlook its impacts on our biodiversity. Displacement from one’s habitat due to flooding leaves species vulnerable to harsher new living conditions, predation from other species, and scarcity or inaccessibility of resources required for survival (Foundation for the Philippine Environment, 2011). Both biodiversity loss and flooding serve as issues faced by the Philippines as a nation. Despite this, there are many measures to address both issues, creating sustainable and safe communities while enhancing biodiversity.

There are nature-borne solutions to which flooding can be prevented. An example of this would be the conservation of mangroves, widely considered to be one of the world’s most important ecosystems. For many communities, mangroves are the first line of defense for flooding and storm events. Every year, in the United States, mangrove systems prevent more than $65 billion in property damage and reduce flood risk to around 15 million people (The Nature Conservancy, 2021). This also includes mangroves’ ability to deal with storm surges and prevent soil erosion. Beyond their role in flood prevention, mangroves are also vital for sustaining biodiversity. More than 1,500 plant and animal species depend on mangroves. This includes fish and birds using shallow waters beneath mangrove trees as nurseries (United Nations Environment Programme, 2023). However, the total footprint of mangroves has declined over the past 35 years, largely due to human activity. A 2024 report identified that 50% of the mangrove ecosystems assessed are at risk of collapse (International Union for Conservation of Nature, 2024). Mangroves have proven to be a great natural solution to many issues we face as a nation.

Coral Reefs serve as natural wave-breakers which can help prevent flooding. Because of their hard, jagged structure, coral reefs can reduce wave energy by 97% and serve as a natural flood defense along nearly 45,000 miles (71,000km) of coastline worldwide (Coral Reef Alliance, 2025). As a species, coral reefs not only have the ability to prevent flooding but also play a massive role in aquatic biodiversity.  About 25% of all marine species are found in, on, and around coral reefs, rivaling the biodiversity of tropical rainforests (Office for Coastal Management, 2025). Philippine coral reefs have declined since the 1970s, and this degradation has posed a risk to biodiversity, food security, and livelihood in the country (Panga et al., 2021). According to a study done in 2018, annual expected damages from flooding would double, and costs from frequent storms would triple without reefs. For 100-year storm events, flood damages would increase by 91% to $US 272 billion without reefs. The countries with the most to gain from reef management are Indonesia, Philippines, Malaysia, Mexico, and Cuba; annual expected flood savings exceed $400 M for each of these nations (Beck et al., 2018). 

Despite the many benefits of flood prevention and biodiversity conservation, there are many roadblocks to the conservation of mangroves and coral reefs. The first comes from human intervention. Pollution, overfishing, destructive fishing practices using dynamite or cyanide, collecting live corals for the aquarium market, mining coral for building materials, and a warming climate are some of the many ways that people damage reefs all around the world every day (National Ocean Service, 2025). Similarly, human impacts such as dredging, filling, water pollution from herbicides, and development can lead to mangrove erosion and habitat destruction (Birch, 2024).

 Destroyed mangroves in Leyte (Source: Beltran, Al Jazeera)