Why is it in the news?
- Cyclone Dana made landfall near Bhitarkanika National Park and Dhamra Port in Odisha, but it did not cause the significant damage that many had feared.
- While the state’s evacuation of one million people to cyclone shelters played a crucial role in minimizing devastation, a vital non-human factor was also at play: the rich mangrove forest cover of Bhitarkanika.
About Mangroves
- Mangroves are salt-tolerant trees and shrubs that typically thrive in estuarine and intertidal regions, where freshwater and saltwater meet. These plants are characterized by aerial breathing roots and waxy, succulent leaves.
- Mangroves are flowering plants, with the Sundarbans—spanning across India and Bangladesh—being the largest contiguous mangrove forest in the world.
- Their seedlings, known as propagules, germinate while still attached to the parent tree before falling into the water and growing into new mangrove trees. Common species include red mangrove (Avicennia marina) and grey mangrove (Rhizophora).
- Mangroves are abundant in swampy and marshy areas and represent a littoral forest ecosystem, thriving in saline or brackish waters along coastal regions.
- In India, notable locations with mangroves include the Godavari Krishna delta in Andhra Pradesh, Bhitarkanika in Odisha, and regions in the Andaman Islands, Kerala, Gujarat, and Tamil Nadu.
Protective Impact of Mangroves Against Cyclones
- Mangrove forests serve as a natural barrier against storm surges—temporary rises in sea level caused by storms that can lead to large waves—by obstructing water flow with their roots, husks, and leaves, as reported by the World Bank Group.
- Another report from the group indicated that certain mangrove species, such as Sonneratia apetala, reduced surge heights from 4 cm to 16.5 cm with 50 m to 2 km wide mangrove strips, and decreased water flow velocity by 29% to 92% with 50 m or 100 m wide mangrove forests.
- When combined with built infrastructure, the protective impact of mangroves against cyclones is further enhanced; for example, planting mangroves in front of embankments can effectively decrease water flow velocity.
About the Vastness of Bhitarkanika’s Mangrove Forest Cover
- Odisha has a mangrove forest reserve covering 231 square kilometres, primarily situated in Bhitarkanika, which ranks second only to the Sundarbans in West Bengal. In addition to Bhitarkanika in Kendrapara, mangroves are also found in the districts of Balasore, Bhadrak, Jagatsinghpur, and Puri.
- Within Bhitarkanika, 82 square kilometres are densely covered with mangroves, while 95 square kilometres have moderate coverage. The coastal areas spanning 672 square kilometres were designated as the Bhitarkanika Wildlife Sanctuary in 1975, and the core area of 145 square kilometres received National Park status in September 1998.
- This park has successfully withstood numerous cyclones in the past, including the devastating Super Cyclone in October 1999.
