The mangroves are a sort of salt resistant vegetation. The plants are generally found in coastal parts of the tropical and sub-tropical region.
They also grow in the sheltered coastlines and creeks across river mouths. The foliages of mangrove species are evergreen with hard, stiff and glossy leaves. The mangroves constitute a dynamic ecological system with a complex association of species of flora and fauna.
Here the combination of terrestrial and aquatic ecosystems is noticed with varieties of life forms making them unique. The best and ideal mangrove forests are seen only in the tidal regions where general temperature does not fall below 20 degree Celsius and there is constant mixing of tidal and fresh water. This is possible only in case of river mouths, where a river joins the ocean.
The mangrove zone and the traits of its vegetation depend on the topography, climate and geomorphologic character of the region. The littoral swamps provide ample scope for rich and fertile ecological system of the region.
A detail ecological study of Odisha coast has not been done so far either by the State Forest Department or by the Union Ministry of Environment and Forests (MoEF). There are more than 60 species of plants which have special types of adaptations with the tidal character of a river-sea micro-climate. In 1921, legendary field botanist Haines Madean took an attempt to explore the floristic compositions of Odisha mangroves but could not complete the task for various reasons. Similarly, botanist HF Mooney also made an attempt during 1950s to complete the incomplete task of Haines but it was not a success. Since then no major efforts have been made to complete the incomplete task of these foresters.
The coastal boundary of India comes to 5,100 km, whereas the coastal boundary of Odisha comes to 529 km. Similarly, 3, 56,500 hectares of land of the coastal India are protected naturally due to presence of the mangrove forests. Odisha has 221 sq km of mangrove forests spread over 82 sq km of very dense, 97 sq km of dense and 42 sq km of open mangrove forests. The State has the second largest mangrove system of the country after the Sundarbans in the Ganga and Hooguli rivers. The mangrove ecosystems of Odisha are basically found in the deltaic regions of Subarnrekha, Budhabalanga, Baitarani, Brahmani, Mahanadi and Devi rivers. Besides, mangrove patches are also found within the river mouth of Rushikulya in Gopalpur deltaic areas and estuaries of Chilka lagoon.
There are sandy sea shores within the coastal boundary of the State, where also the mangrove forests are found. The vegetation of the sandy shores is quite different from the deltaic regions. Similarly, the bio-diversities of these two geographic situations are quite different from each other. The sandy beaches are more prone to different types of climatic hazards than mangrove coasts. The mangrove ecosystems act as protective barriers against ocean. A very peculiar geographic formation is noticed within the oceanic region. Innumerable meandering creeks, channels, islets, swamps and isolated water bodies are found which provide habitats for a large number of amphibians and aquatic creatures.
12 States such as Andhra Pradesh, Goa, Gujarat, Karnataka, Kerala, Maharashtra, Odisha, Tamil Nadu, West Bengal, Andaman and Nicober Islands, Daman and Diu and Puducherry have mangrove forests.
The mangrove forests stabilise the loose soils which are newly formed. The crop compositions filter the sand particles and save land from tidal erosion, cyclone and other sea based disasters. They provide a fertile base and field for fish culture, marine invertebrates, resident and seasonal birds. The tangles of root system of mangrove forests provide better opportunities for algae, sponges, oysters, fishes, prawns, shrimps, lobsters, crabs etc to grow. The mangroves provide livelihood for vast coastal populations.
(The writer is a former senior forest officer and an environmentalist. Tel no 9937460649)