Mangrove Forest and Plantation

PRADEEP KHANNA'

Former Chief Conservator of Forest, Gujarat, India.

*Corresponding author. E-mail: This email address is being protected from spam bots, you need Javascript enabled to view it

ABSTRACT

Mangroves, which were once considered wastelands, are being increasingly recognized for their ecological services that they perform as inshore stabilization, protection from cyclones/storms/tsunami, home to marine biodiversity, etc. Mangroves prosper in warm tropical regions. More than 40% of world mangroves are found in Asia. Mangrove forests in India extend over 4921 km2 in 12 states and union territories. The Sundarbans, recognized as a heritage site, extending to over 6000 kin2 in India and Bangladesh support a contiguous patch of mangrove forests that are the largest mangrove forests of the world. Gujarat coasts support the second largest area of mangrove with 1140 km2 of mangrove forests. Mangroves received attention, and efforts for its rejuvenation started, after the declaration of Marine National Park in 1980. The mangrove cover increased from an estimated 427 km2 in 1987 to 1140 km2 in 2017, over two-and-a-half-fold increase. Gujarat is the only state of India that has reported such significant increase in mangrove forests. Though the diversity of species of mangrove species in Gujarat is restricted to fourteen species, the education awareness has played a significant role in making a success of mangrove conservation program in Gujarat. The GEER Foundation has made a significant contribution in providing research inputs with support of Mangrove for Future and IUCN. Detailed mapping of mangroves and potential areas for mangrove has been done.

INTRODUCTION

Mangroves now recognized for their high productivity and variety of economic and ecological sendees were considered as wastelands holding little intrinsic value till first half of the twentieth century and attracted little attention. Large mangrove areas were reclaimed for a variety of economic activities. It was in later part of the 20th century that importance and value of mangroves were recognized.

Mangroves are highly productive ecosystems. They are a special type of vegetation occupying the mudflats at the boundary of marine and terrestrial environment. They stand with their roots in tidal region in salty marine water. Thus, one of the special characteristics of this group of vegetation is its salt tolerance. They are predominantly found in tropics. They thrive in the environment near mouths of large rivers, where river deltas provide lot of sediment. The mangrove cover in the world is estimated at 18 million ha with about 40% in Asia (Spalding, 1997). Countries with large tracts of mangrove forests are Indonesia (45,421 km2; Spalding, 1997), Brazil (13,800 km2; Spalding, 1997), Bangladesh (5767 km2, Spalding, 1997), and India (4921 km2, Anonymous SFR, 2017).

Last 50 years we observed increasing appreciation of ecological importance of mangrove forests for a variety of ecological services they provide. These include:

  • a) Shoreline stabilization: Mangroves function as a stabilizer of sediment that is deposited by the geomorphological process.
  • b) Protection from cyclones and storms: Mangroves are susceptible to damage from storms and cyclones. Yet they provide protection from the severity of devastation caused by storms, cyclone, and even tsunami.
  • c) Maintenance of channel depth: Stabilization of coastal sands helps to maintain channel depth for uninterrupted navigation.
  • d) Marine life conservation: Mangrove provides an environment for the conservation of a variety of marine life that includes fishery and wild marine life. It includes marine life that thrives in the mangrove region as also marine life beyond the mangroves.
  • e) Coral conseivation: Mangroves contribute to coral conseivation by retaining silt from moving over corals and restricting algal growth due to eutrophication.
  • f) Wildlife conservation: Mangroves are safe home to a large variety of birds, resting and feeding areas for migratory birds and are known to support large heronries.
  • g) Timber and fodder for the local community
  • h) Offer ecotourism opportunities that provide employment opportunities to the local community.

i) Carbon sequestration: Mangrove forests are efficient for carbon sequestration. The primary productivity of mangroves is amongst the highest of natural ecosystems (Ong, 2013).

Mangroves prefer warm tropical regions. However, there are variations in the latitude range for mangrove occurrence in different geographic regions. In Pacific Asia where over 40% of the mangrove forests occur the northern limit of mangrove is defined at 31 °22' N latitude. In the Western and Eastern Australia, the southern limit of the mangrove is defined at 33° 16' S and 38°45' S, respectively. The region for mangroves is identified as 32°20' N and 28°56' S in Atlantic America and 30°15' N and 5°32' in Pacific America. The latitude range for mangroves in the Atlantic Africa is 19°50' N to 12°20' S. However, in Eastern Africa/Red Sea the latitude range for mangrove is reported as 27°40' N to 32° 16' S. The cause of variation in ranges of latitude in which mangroves are found in various geographic regions seems to relate to variation in temperature range (World Mangrove Atlas, 1997, Spalding et al., 1997).

MANGROVES OF INDIA

Mangrove forests in India extend over 4921 km2 in 12 States and union territories (Anonymous SFR, 2017). Significant mangrove forests are in the states Andhra Pradesh 404 km2, Gujarat 1140 km2, Maharashtra 304 km2, Odisha 243 km2, West Bengal 2114 km2, and Andaman & Nicobar Islands 617 km2 (Anonymous SFR, 2107). Sundarbans’ mangroves estimated as over 6000 km2 (Bangladesh, 4050 km2; India, 2050 km2) form a continuum across India and Bangladesh is the largest tract of mangroves in the world (Spalding, 1997). The Sundarbans’ mangroves of India constitute the largest Mangrove area of India. Sundarbans mangrove forests occupy the deltaic region of Ganga, Brahmaputra, and Meghna rivers. There are numerous islands in the region. In some literature, Sundarbans is recognized as a wonder of the world for its occurrence in a densely populated region. The Sundarbans are declared a heritage site of UNESCO with Indian Sundarbans listed as Sundarbans National Park while Bangladesh Sundarbans as Sundarbans heritage site. Sundarbans support large biodiversity that includes a diversity of mangrove species, wildlife, including the Royal Bengal Tiger, estimated at about 500, and host of other terrestrial, amphibians, and aquatic wildlife.

MANGROVES OF GUJARAT

Gujarat has a 1600-kin long coastline that accounts for about 30% of India’s coastline. The coastal region along this long coast varies significantly in topography, climate, and edaphic factors. Mangroves are largely concentrated in the Saurashtra and Kutch regions. Singh reported in 1999 that the notified mangrove forest’s area in Kutch, Jamnagar, (now divided into Jamnagar and Devbhumi Dwarka), and Rajkot (now Morvi) districts is 1324.40 knf.

Gujarat coasts support the second largest area of mangrove with 1140 km2 of mangrove forests (Anonymous SFR, 2017). Stoiy of mangrove conservation in Gujarat is unique for the major gains in conservation. In early 1980s, there was an emergence of interest in the conservation of marine flora and fauna. The first marine protected area of India Marine National Park (MNP) and Sanctuary constituted along the southern coast of Gulf of Kutch in 1980. The new administrative unit constituted to develop and manage the newly constituted marine-protected area initiating a variety of efforts that included mapping of mangrove areas, identification of coral- rich sites, biodiversity survey for marine life in the region and also included mangrove plantation experiments.

Although over 1325 kin2 of the area is notified as mangrove forests, the actual mangrove cover was much less. There are large blanks including hypersaline mudflats included in notified mangrove forests. It also includes 103.25 km2 area leased out to 21 salt industries in Jamnagar district. There are few patches of mangrove near Kandla port, Surajbari, Mundra port, and in Kori creek that are not notified as forests (Singh, 1999).

The Imperial Gazetteer of India, Vol. XVIII (1908), mentions that in Navanagar (now Jamnagar) state, mangrove swamps line the shore of Gulf, affording large supplies of firewood and pasture. The Saurashtra and Kutch are semiarid and arid and have high evapotranspiration. There is no major river system or peremiial river in the region. The conditions thus are not conducive to rich and luxuriant mangrove forests. However, Chavan (1985) recorded dense high forests with a height of up to 14 m albeit supporting little diversity of tree species in mangroves of Jamnagar.

The mangrove areas in other parts of Gujarat received little attention and recognition. The meager mangroves in Gulf of Cambay are mainly restricted to Surat and Valsad districts with virtual absence at Khambhat and its adjoining areas and little documentation reflect at little attention they received.

THE REJUVENATION

Increased interest and thrust in the conservation of marine biodiversity and mangrove conservation was observed, In early 1980s, Southern coastal region in the Gulf of Kutch with the islands that supported corals and significant biodiversity of marine fauna were notified as a sanctuary and the high diversity core area as MNP. The 457.92 km: area of the intertidal zone and the islands, locally called Bets, were notified as a marine sanctuary under the Wildlife Protection Act, 1972. The high biodiversity critical areas, 162.89 km2, were at the same time notified as MNP under the same act. A special unit headed by a conservator of forest was constituted to manage the wildlife and mangrove areas in the southern region of Gulf of Kutch. Until 1982, Digvijay Cement Company had lease to dredge coral areas including that of Pirotan, Kalvan, Jindra, Dhani, Dera, and Goose for calcium carbonate for cement manufacture. The advent of MNP changed the situation to favor conservation. The dredging of corals stopped as the state government canceled the lease and the MNP authorities started conservation efforts for corals and mangroves.

 
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