Forestry Department Food and Agriculture Organization of the United Nations

Transcription

1 Forestry Department Food and Agriculture Organization of the United Nations GLOBAL FOREST RESOURCES ASSESSMENT 2005 THEMATIC STUDY ON MANGROVES INDIA COUNTRY PROFILE DRAFT, JUNE 2005 Forest Resources Development Service Forest Resources Division Forestry Department FAO, Rome (Italy)

2 DISCLAIMER The designation employed and the presentation of materials in this information product do not imply the expression of any opinion or whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. This paper does not reflect any official position of FAO. Please refer to the FAO website ( for official information. The purpose of this paper is to provide early information on on-going activities and programmes, to facilitate dialogue, and to stimulate discussion. Contact person: Mette Løyche Wilkie, Senior Forestry Officer Global Forest Resources Assessment Forest Resources Division Forestry Department FAO Viale delle Terme di Caracalla Rome (Italy) FAO 2005

3 INTRODUCTION Mangroves are found along sheltered coastlines in the tropics and sub-tropics where they fulfil important functions in terms of providing wood and non-wood forest products, coastal protection, conservation of biological diversity and provision of habitat, spawning grounds and nutrients for a variety of fish and shellfish. High population pressure in coastal areas has led to the conversion of many mangrove areas to other uses and numerous case studies describe mangrove losses over time. However, information on status and trends at the global level is scarce. The first attempt at estimating the total mangrove area in the world was undertaken as part of the FAO/UNEP Tropical Forest Resources Assessment in 1980, where the world total was estimated as 15.6 million hectares. More recent estimates range from 12 to 20 million ha. For many of these studies, countries with small areas of mangroves were excluded due to lack of information and because their combined area of mangroves would not significantly affect the world total. A recent initiative by FAO aimed at facilitating access to comprehensive information on the current and past extent of mangroves in 121 countries and areas (FAO. 2003). This built on the earlier FAO/UNEP assessment and on the recent FAO Global Forest Resources Assessment 2000 (FRA 2000). An extensive literature search yielded additional information. More than 2800 national and sub-national datasets were collected, with the earliest estimates dating back to One of the results was an updated list of the most reliable, recent estimate for each country, mostly based on inventories or analysis of remote sensing imagery. Regression analyses based on earlier data provided estimates for 1990 and 1980 and an extrapolated estimate for 2000 for each country. The preliminary results of this initiative showed that mangrove deforestation continues, albeit on a slightly lower rate in the 1990s than in the 1980s. The relatively large mangrove deforestation rates in Asia, the Caribbean and Latin America in the 1980s reflect large-scale conversion of mangroves for aquaculture and tourism infrastructure. Most countries have now banned the conversion of mangroves for aquaculture purposes and require environmental impact assessments prior to large-scale conversion of mangroves areas for other uses. In order to provide the most accurate and comprehensive evaluation of current mangrove status, FAO is presently updating the above cited preliminary results, which have been sent out to all countries and areas in which they exist (124) for information and validation. Additional literature search, active collaboration with national and international mangrove experts and the use of remote sensing imagery interpretation have further supported the preparation of the final report, which will be published in Readers are strongly encouraged to provide feedback and additional information to help update and improve this database for the benefit of all those who may have an interest in mangroves.

4

5 India Vegetation description India has a coastline of some km divided into west and east coasts, with patchy mangrove distribution. About 80 percent of India's mangroves are found in the east where the coastal profile is typically less steeply shelving and rivers and estuaries are better developed. The largest areas are those of the Indian part of the Sundarbans (West Bengal) followed by Gujarat and Andaman & Nicobar Islands. The Indian Sundarbans are slightly more saline than the Bangladeshi Sundarbans, with poorer forest development. The Andaman and Nicobar Islands have close affinities to the nearby Southeast Asian mangroves. Other mangrove areas on the eastern coast are associated with the estuaries of the Mahanadi, Godavari, Krishna, and Cauvery Rivers. On the west coast, mangroves are fringing the estuaries of many small rivers, while there are important scrubby communities associated with the arid coast around the Gulf of Kutch. The mangrove forest in India has the form of an evergreen closed high forest that can reach up to 30 m or more in height. It consists especially of Heritiera sp. or, less commonly, of Bruguiera sp. There may be an underwood of the same species or of others, such as Ceriops sp. This two-storied forest type is common due to the prevalence of trees which maximum height is only 5-10 m mixed with others capable of further development. Rhizophora sp. replaces Heritiera sp. nearer to the sea. There are a few other tree genera, such as Sonneratia, Avicennia and Excoecaria, and shrubs and palms among which Acanthus sp. and Nypa fruticans are the most common. Uses and threats Mangroves have been exploited for thousands of years in India leading to severe area losses; in Andaman and Nicobar Islands only, around ha have been lost between 1987 and Most estuarine mangrove areas have human communities close by, and the Sundarbans mangroves have a resident population of some two million people. Local uses include fuelwood, fisheries, honey production and the use of Nypa leaves for roofing materials. Some people live by selling mangrove firewood which is the only source of firewood in the region in the Gulf of Kutch; mangroves are also heavily degraded by camel and cattle grazing. Salt collection is also an important activity in the supralittoral zone, especially in the Kutch region. Traditional aquaculture has a long history together with pond construction for fish and shrimp cultivation, which has recently been boosted by the development of hatchery technology. In some areas polyculture techniques rotate paddy cultivation with prawn farming. Large areas of land have been reclaimed for agricultural purposes and urban development, which is increasing with population pressure in all areas; Mumbay (Bombay) for example, is built on an area that in 1670 was a group of seven islands surrounded by mangroves. Due to human pressure pollution from urban and agricultural runoff represent an increasing threat. On the east coast, a number of mangrove areas are managed for timber with detailed Forest Working Plans and felling cycles varying from 20 to 100 years. In other zones over-exploitation threatens many areas, including the Gulf of Kutch and the Sundarbans. Besides human threats, mangroves in India have to face many different natural hazards, such as cyclones, wind and tsunamis; studies are currently on-going in order to assess the damage caused to mangrove forest by the 26th December 2004 tsunami, at the same time their role in protecting the coast and smoothening the strength of the waves is also being evaluated A National Mangrove Committee was established in 1976, now superseded by a National Committee on Wetlands, Mangroves and Coral Reefs, as an advisory body to the Government of India. This body has identified 15 key mangrove areas, including all of the 1

6 large sites mentioned above, and has drawn up Management Action Plans for all of them, to be administered by the state governments with financial assistance from the Ministry of Environment and Forests. Small afforestation schemes have been undertaken, notably in the Gulf of Kutch. A number of sites have also protected by law, including part of the Gulf of Kutch, the Great Andaman Biosphere Reserve and three sites in the Sundarbans. In addition to this the M. S. Swaminathan Research Foundation has restored ha of degraded forest by community based mangrove management project along the east coast of India. Hyper saline water was drained out from the troughs formed due to the past management practise of coup felling. The same method has been used by the state forest department and some NGO s to restore large areas of degraded mangroves. Indian mangroves offer a very good habitat for many different animal species and are used as resting and feeding sites by a large variety of birds, both migratory and resident. Besides human threats, mangroves in India have to face many different natural hazards, such as cyclones, wind and tsunamis; studies are currently ongoing in order to assess the damage caused to mangrove forest by the 26 th December 2004 tsunami, at the same time their role in protecting the coast and smoothening the strength of the waves is also being evaluated. Bioinformatics Centre (National Institute of Oceanography) Mangroves of India. FAO, UNEP Tropical Forest Resources Assessment Project, Forest Resources of Tropical Asia. FAO, UNEP, 475 pp. FSI State of Forest Report, Forest Survey of India, MOEF, GOI, India. Ravishankar, T., M. Navamuniyammal, L. Gnanappazham, Satya Shree Nayak, Gopal Chandra Mahapatra and V. Selvam Atlas of Mangrove Wetlands of India, Part III : Orissa Chennai, M.S. Swaminathan Research Foundation, xv, 102 p., figs., maps. Spalding, M.D., Blasco, F. and Field, C.D., eds World Mangrove Atlas. The International Society for Mangrove Ecosystems, Okinawa, Japan. 178 pp. 2

7 National level mangrove estimates In order to provide the whole range of the information currently available on mangrove area extent for this country, all the national level mangrove area estimates collected so far have been reported in the following table. Differences in methodologies, classifications, mapping scales etc. may have led to discrepancies in figures, thus only the estimates considered as the most accurate and reliable (marked in the Trend column in this table) have been used for the analysis of the area changes over time. Year Area (ha) Source Trend Methodology/Comments Waheed Khan Cited in: Chaudhuri, A.B. and Choudhury, A Mangroves of the Sundarbans. Vol. 1. India. The IUCN Wetlands Programme. Bangkok, Thailand, IUCN. This figure could include also water Mathauda, G.S The mangrove of India. In Proceedings of the Mangrove Symposium. p Calcutta Sidhu Studies on Mangrove. National Academy of Sciences. Vol 33b Part 1. p Andaman and Nicobar Islands; Andra Pradesh, Gujarat, Maharashtra, Orissa, Tamil Nadu, West Bengal: Sidhu Studies on Mangrove. National Academy of Sciences. Vol 33b Part 1. p Goa, Karnataka: Untawale, A.G Present Status of Mangrove Along the Coast of India. In: proceedings of the Asian Symposium on Mangrove Environment Research and Management, Kuala Lumpur, August 25-29, Edited by E. Soepadmo, A.N. Rao and D.J. MacIntosh p Kerala: Sparse mangroves Blasco, F The Mangroves of India. Institut Francais de Pondichery. Pondichery. Cited in: Chaudhuri, A.B. and Choudhury, A Mangroves of the Sundarbans. Vol. 1. India. The IUCN Wetlands Programme. The breakdown is provided. Cited in: FAO Management and utilization of mangroves in Asia and the Pacific. FAO Environment Paper pp. This extent includes also water. Combined National Level Mangrove Estimate. This figure should be considered as on the higher side. Cited in: FAO Management and utilization of mangroves in Asia and the Pacific. FAO Environment Paper pp. 3

8 Year Area (ha) FAO, UNEP Tropical Forest Resources Assessment Project, Forest Resources of Tropical Asia. FAO, UNEP, 475 pp. Source Trend Methodology/Comments Based on the information provided by Champion, H.G. and Seth, S.K A Revised Survey of the Forest Types of India. Publication Division, Government of India - Delhi. Anon Atlas of Forest Resources of India. National Atlas Organization. Calcutta. The area has been updated to year 1980 on the basis of annual deforestation rates Ibid X All the most reliable information available per province has been analysed and processed through the regression analysis. The 1980 figures obtained for each region 1980 have been used Forest Survey of India The state of Forest Report Forest Survey of India, MOEF, GOI, India Wacharakitty, S Mangrove Ecosystem in General. In: ESCAP/UNESCO/NRCT Regional Remote Sensing Training Course of Mangrove Ecosystem. p Bangkok, Nov. 28-Dec Forest Survey of India State of Forest Report Forest Survey of India, MOEF, GOI, India Government of India Mangroves in India. Government of India, Ministry of Environment & Forests, New Delhi. 150 pp Jagtap, T.G., Chavan, V.S. and Untawale, A.G Mangrove Ecosystem of India: A need for Protection. Ambio 22 (4) Forest Survey of India The State of Forest Report Forest Survey of India, MOEF, GOI, India Interpretation of LANDSAT MSS imageries; resolution 80 m; scale of interpretation: 1:1 million. Breakdown provided per State/Union Territory. The year is the mid-year of the imagery data period. Cited in: FAO Mangrove forest management guidelines. FAO Forestry Paper 117. Rome, 319 pp. Interpretation of LANDSAT MSS imageries; resolution 30 m; scale of interpretation: 1: Breakdown provided per State/Union Territory. The year is the mid-year of the imagery data period. Cited in: FSI State of Forest Report, Forest Survey of India, MOEF, GOI, India. And FAO Global Forest Resources Assessment (GFRA) 2005 country report - India. Unpublished. Secondary reference, no primary source provided. The "Year" is the publication year. Remote sensing, the figure it is not very accurate. Interpretation of LANDSAT MSS imageries; resolution 30 m; scale of interpretation: 1: Breakdown provided per State/Union Territory. The year is the mid-year of the imagery data period. 4

9 Year Area (ha) Forest Survey of India The state of Forest Report Forest Survey of India, MOEF, GOI, India Forest Survey of India The state of Forest Report Forest Survey of India, MOEF, GOI, India Nayak, S Role of Remote Sensing Application in the management of wetland ecosystems with special emphasis on Mangroves. Lecture delivered at the UNESCO Curriculum Workshop on Management of mangrove Ecosystem and Coastal Ecosystem, Department of Marine Living Resource, Andhra University, Vishakhapatnam Forest Survey of India The state of Forest Report Forest Survey of India, MOEF, GOI, India Spalding, M.D., Blasco, F. and Field, C.D., eds World Mangrove Atlas. The International Society for Mangrove Ecosystems, Okinawa, Japan. 178 pp. Source Trend Methodology/Comments Interpretation of LANDSAT MSS imageries; resolution 30 m; scale of interpretation: 1: Breakdown provided per State/Union Territory. The year is the mid-year of the imagery data period. Cited in: FSI State of Forest Report, Forest Survey of India, MOEF, GOI, India. And FAO Global Forest Resources Assessment (GFRA) 2005 country report - India. Unpublished. Interpretation of IRS-1B LISS II imageries; resolution 36.5 m; scale of interpretation: 1: Breakdown provided per State/Union Territory. The year is the mid-year of the imagery data period. Cited in: FSI State of Forest Report, Forest Survey of India, MOEF, GOI, India. And FAO Global Forest Resources Assessment (GFRA) 2005 country report - India. Unpublished. Remote sensing. Visual and digital interpretation, aided by ground checking on more than 2000 spots. Interpretation of IRS-1B LISS II imageries; resolution 36.5 m; scale of interpretation: 1: Methodology does not allow identification of forest areas smaller than 25 ha. Breakdown provided per State/Union Territory. The year is the mid-year of the imagery data period. Cited in: FSI State of Forest Report, Forest Survey of India, MOEF, GOI, India. And FAO Global Forest Resources Assessment (GFRA) 2005 country report - India. Unpublished. Map analysis. Scale 1:1,000,000. According to the authors, the estimate by WWF-India personal communication ( ha) is likely to be more accurate. 5

10 Year Area (ha) WRI, UNEP, UNDP, The World Bank World Resources New York and Oxford University Press 365 pp Anon Status of forest cover. Forest Survey of India, Dehra Dun Forest Survey of India The State of Forest Report Forest Survey of India, MOEF, GOI, India Aizpuru, M., Achard, F., and Blasco, F Global Assessment of Cover Change of the Mangrove Forests using satellite imagery at medium to high resolution. In EEC Research project n FIED ISP FR Joint Research center, Ispra Forest Survey of India State of Forest Report, Forest Survey of India, MOEF, GOI, India. Source Trend Methodology/Comments X Secondary reference, no primary source provided. The "Year" is the publication year. It is probably an approximate figure Cited in: Singh, H.S Mangroves in Gujarat on path of recovery - A success story. Indian Forester, April Interpretation of IRS-1C/1D LISS II imageries; resolution 23.5 m; scale of interpretation: 1: Breakdown provided per State/Union Territory. The year is the mid-year of the imagery data period. Also cited in: V. Selvam, L. Gnanappazham, M. Navamuniyammal, K.K. Ravichandran and V.M. Karunagaran Atlas of Mangrove Wetlands of India : Part I - Tamil Nadu. Chennai, M.S. Swaminathan Research Foundation, 100 p., tables, maps. National level estimate based on extrapolation of a remote sensing case study for Ganges and literature review. Digital interpretation of 2000 IRS-1C/1D LISS II; resolution: 23.5 m; scale of interpretation: 1: Breakdown provided per State/Union Territory. The present assessment should be taken as the baseline information on mangrove cover for India and it cannot be used to estimate increase or decrease from previous FSI assessments. Discrepancies in extent estimates may be caused by change in methodology (visual to digital interpretation) and scale of interpretation (from 1:1 million to 1:50 000). 6

11 Mangrove species checklist Following Tomlinson 1987 classification, mangroves may be divided into three groups according to their features: major elements (strict or true mangroves), minor elements and mangrove associates. Tomlinson list of true mangrove species have been here modified by adding some species commonly found as exclusive mangrove species (Saenger et al. 1983) In the context of this assessment, only true mangroves species will be reported: Acanthus ilicifolius Acrostichum aureum Aegialitis rotundifolia Aegiceras corniculatum Avicennia alba Avicennia marina Avicennia officinalis Bruguiera cylindrica Bruguiera gymnorrhiza Bruguiera parviflora Bruguiera sexangula Ceriops decandra Ceriops tagal Cynometra ramiflora Excoecaria agallocha Heritiera fomes Heritiera kanikensis Heritiera littoralis Kandelia candel Lumnitzera racemosa Rhizophora apiculata Rhizophora mucronata Rhizophora stylosa Rhizophora lamarckii Scyphiphora hydrophyllacea (rare) Sonneratia alba Sonneratia apetala Sonneratia caseolaris Sonneratia griffithii Xylocarpus granatum Xylocarpus mekongensis 7

12 Trends in mangrove area extent over time ha Year Figures used for trends Figures not used for trends Calculated estimates Trend Estimates of Indian mangrove area extent have been made by several authors over time, the discrepancy resulted from the comparison between some of them may be explained by changes in resolution of satellite imageries, differences in methodologies and in scale of interpretation.

13 Summary status of mangrove area extent over time Most reliable, recent mangrove area estimate Mangrove area estimate 1980 Mangrove area estimate 1990 Mangrove area estimate 2000 Mangrove area estimate 2005 ha year ha ha ha ha India References FAO Forest Resources assessment 1990: Global synthesis. FAO Forestry Paper No Rome, 46pp. FAO Global Forest Resources Assessment 2000: main report. FAO Forestry Paper No Rome. FAO Status and trends in mangrove area extent worldwide. By Wilkie, M.L. and Fortuna, S. Forest Resources Assessment Working Paper No. 63. Forest Resources Division. FAO, Rome. (Unpublished) Saenger, P., Hegerl, E.J. & Davie, J.D.S Global status of mangrove ecosystems. Commission on ecology papers No. 3. Gland, Switzerland, IUCN. Tomlinson, P.B The botany of mangroves. Cambridge Tropical Biology Series, Cambridge, 419 pp. 9

14 Explanatory notes Figures used for trends The estimates used for the trend analysis has been marked with an X in the Trend column in the country specific table; it has been coloured in green - with no patterns - in the chart. Most recent reliable figures The figure chosen as the most recent reliable is underlined in the country specific table; in the chart it has been bolded. Formulas used for the trend analysis Linear: y = mx + b where m is the slope and b is the intercept. 10

15