Wetlands Ecology and Management

, Volume 18, Issue 3, pp 321–331

Valuing mangrove benefits: contribution of mangrove forests to local livelihoods in Bhitarkanika Conservation Area, East Coast of India

Authors

    • Wildlife Institute of India
  • Ruchi Badola
    • Wildlife Institute of India
Original Paper

DOI: 10.1007/s11273-009-9173-3

Cite this article as:
Hussain, S.A. & Badola, R. Wetlands Ecol Manage (2010) 18: 321. doi:10.1007/s11273-009-9173-3
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Abstract

The consumptive benefits of mangrove forests to subsistence economy receive little recognition. This paper quantifies the value of provisioning services of mangrove forests to local livelihoods in terms of forestry and fishery products. To examine the use of mangrove products, 324 households from 36 villages in the Bhitarkanika Conservation Area located in East Coast of India were surveyed using structured questionnaires. For estimating the contribution of mangrove forests to fish productivity, fish production was evaluated in three stages—inshore fishery, offshore fishery and the role of mangrove forests as nursery ground for fish and shellfish. The findings revealed that 14.2% of the fuel need of each household was being met by the forests. Other forestry products used were timber, honey and thatch grass. During the study, 14 species of fish and three of shellfish were recorded. The total catch for inshore fishery was estimated as 3.77 kg h−1 having market price of US$ 2.25. In offshore fishery the number of species caught as well as income from the catch was higher in areas with mangroves (US$ 44.61 h−1) than in those without mangroves (US$ 2.62 h−1). The market price of the forestry and fishery products used by the people was estimated as US$ 107 household−1 annum−1. The resources extracted from mangrove forests contributed to more than 14.5% of the total income of the household. This was around 30% for the households residing in the immediate vicinity of the forests. This study suggests that provisioning services provided by the mangrove forests are of significant importance to the coastal communities as they increase the resilience and sustainability of the local economy.

Keywords

Mangrove ecosystemsLocal livelihoodsResource dependencyFisheryEcosystem servicesEconomic valuation

Introduction

The mangrove ecosystems are recognized as providers of a wide variety of goods and services to people including provision of plant and animal products (Macnae 1974; Rosolofo 1997; Spaninks and Beukering 1997), sediment trapping and nutrient uptake and transformation (Furukawa et al. 1997; Hussain and Badola 2008), protection from floods and storms (Maltby 1986; Gilbert and Jansen 1997; Semesi 1998; Sathirathai and Barbier 2001; Kathiresan and Rajendran 2005; Dahdouh-Guebas et al. 2005; Badola and Hussain 2005) and stabilization of coastal land (Carlton 1974; Wolanski 1985). Ecosystem services like protection against floods and storms and reduction of shoreline and riverbank erosion sustain economic activities in coastal areas throughout the tropics (Moberg and Rönnbäck 2003). Local communities in coastal areas are directly benefited from mangrove resources in terms of forestry and fishery products (Bandaranayake 1998; Sathirathai and Barbier 2001; Richman 2002; Moberg and Rönnbäck 2003; Hoq et al.2006; Shervette et al.2007). Food and beverages from the mangroves include fish, crustaceans, shellfish, sea cucumbers, other invertebrates, edible species of oysters, mussels, cockles and gastropods, wildlife, honey, condiments, tea substitutes and sugar (Gilbert and Jansen 1997).

The estuarine and mangrove systems are good nursery grounds for economically important near shore fish and shellfish species (Miller et al. 1983; Little et al. 1988). Snedaker and Snedaker (1984) estimated that more than 90% of near shore marine species were found in the mangroves during one or more parts of their life cycles. There is positive correlation between mangrove area and prawn/shrimp landings (Primavera 1995, 1998). In tropical developing countries, 60% of the people depend on fish for 40% or more of their protein demand. The majority of the world’s fish catch (87%) comes from marine areas. In India, the largest fish production comes from the coastal capture fisheries of inshore waters (<50 m depth), which constituted about 82% of the total marine capture fish production of 2.7 million tons in 1997 (Sudarshana et al. 2000).

However, the consumptive contribution of mangroves to the livelihoods of coastal communities is often ignored and receives little recognition from the researchers, policy makers and practitioners (IIED 1995; Narendran et al. 2001; Delang 2006). One of the reasons is that little information is available on the types of goods and the quantity extracted, processed or sold. Collecting such information is generally time consuming due to high degree of spatial and temporal variability and price estimation in case of subsistence use (Eaton and Sarch 1997). Furthermore, most of the products are consumed directly by the gatherers and do not enter the market. Therefore, when evaluating mangroves for contribution to food for coastal communities, these have to be viewed as dynamic ecosystems with non-linearties, thresholds and discontinuities (Costanza et al. 1993). Since the non-marketed non-wood forests products (NWFP) would disappear if the mangroves are clear cut, the value of these products should be included together with its value as a carbon sink (Twilley et al. 1992; Bouillon et al. 2008), as a protection against storms and floods (Badola and Hussain 2005), the value of its biological diversity and recreational and option values among others. Hence, any economic analysis trying to estimate the value of mangrove without recognizing their contribution to subsistence economies will be incomplete. In this paper, the contribution of mangrove forests to local livelihoods in terms of forestry and fishery products is quantified and monetized. This study was conducted in the Bhitarkanika Conservation Area in the east coast of India which harbors the second largest mangrove ecosystem of mainland India.

Study area

The Bhitarkanika conservation area

The Bhitarkanika estuary is situated at the lower reaches of the Brahmani and Baitarani river flood plains in the east coast of India. The area is the microenvironment region of the Dhamra-Pathsala-Maipura estuary of Rajnagar Block in Kendrapada and Bhadrak districts of Orissa and consists of the second largest mangrove forest of mainland India. Geographically, it is located between 86°45′E–87°50′E longitude and 20°40′N–20°48′N latitude. The entire Bhitarkanika estuarine system has significant conservation value and has been protected as Bhitarkanika Wildlife Sanctuary and the Gahirmatha Marine Sanctuary. The Bhitarkanika Wildlife Sanctuary and parts of the Gahirmatha Marine Sanctuary together with 336 villages and adjacent agricultural land are referred to as Bhitarkanika Conservation Area (BCA; Fig. 1). The total area of the BCA is 1006.5 km2 which includes 35 km long open coastal ecosystem of the Gahirmatha Marine Sanctuary in the Bay of Bengal.
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Fig. 1

Location of Bhitarkanika Conservation Area, East Coast of India, its land use pattern and the Gahirmatha and Paradip coast

The mangrove forests in the BCA consist of 145 km2 of intact forests notified as a National Park, and 385 km2 of degraded forests comprising the Bhitarkanika Wildlife Sanctuary. The National Park is free of human habitation where as the Sanctuary is interspersed with 336 villages. The deltaic mangrove swamps of BCA are extremely low lying and subjected to regular tidal inundation. The general elevation above mean tide level is between 1.5 and 2 m (Dani et al. 1999). The climate of the area is tropical characterized by three distinct seasons; summer (March–June), winter (November–February) and monsoons (July–October). Annual rainfall averages 1,670 mm with the main rainfall occurring during the monsoon months of August and September. In summer, the mean monthly temperature ranges from 20–30°C whereas during the short winter it is 15–20°C (Kar and Bustard 1986). The mean monthly relative humidity remains between 75–80% throughout the year.

A total of 64 species of plants were recorded from the area, which included 28 true mangroves, four mangrove associates and 32 other species. The overall tree density was 1376.93 trees ha−1, the most dominant species being Excoecaria agallocha followed by Heritiera littoralis, Avicennia officinalis and Cynometra ramiflora. The sapling and seedling density was 83.33 and 45.79 ha−1, respectively. The total tree basal area was 220.26 m2 ha−1 and mean basal area per tree was 0.16 m2 tree−1.

Methods

The dependency of local people on mangrove forests was estimated in 36 villages situated in the BCA. These villages were selected on the basis of 35 parameters through a hierarchical cluster analysis (Sokal and Rohlf 1995) followed by a random selection from each of the clusters proportionately (Badola and Hussain 2005). For each selected village 10% of the housing units were picked up randomly for the household survey. A point was made to evenly distribute the household over the total area of the villages in order to get a full representation of all communities and economic groups. Using structured questionnaires, information on demography, land use, income and occupational pattern as well as local dependence on mangrove resources was collected from 324 intensively surveyed households. During the survey, the types of goods and their amount extracted were quantified. For estimating the contribution of Bhitarkanika mangrove ecosystem to fish productivity, we evaluated the fishery production in three stages—inshore fishery, offshore fishery, and the role of Bhitarkanika mangrove ecosystem as nursery ground for fish and shellfish.

Inshore fishery

Fish and shellfish production in six creeks of the Bhitarkanika National Park were sampled to estimate the species composition and quantity caught. Bhitarkanika being a Protected Area, a least-damage sampling strategy was adopted to minimize any damage to fish population. Where possible, in situ observation and identification of fish species were done and fish were released back into the water following Zakaria et al. (1999). Local gears in the form of float nets were used for sampling. The nets were set across the river and the total catch at each 30 min interval was recorded. After sorting the catch to the species level, the individual total weights were recorded following Koranteng et al. (2000). Sampling was done at all the sites every fortnight during low tide.

Nursery ground for fish and shellfish

The fish seedlings and shellfish were collected from six creeks in the Bhitarkanika National Park using a circular drag net of 1 m diameter. The sampling was done during low tide and the nets were dragged for about 100 m. At each site four sampling efforts were made fortnightly. The species caught, their number and total weight of the catch were recorded.

Offshore fishery

To examine the contribution of Bhitarkanika mangrove ecosystem to offshore fishery we selected two fish landing stations, Dhamra and Talchua situated close to Bhitarkanika having mangroves on shore, and the Paradip port away from Bhitarkanika, from where most of the mangroves have been removed. We monitored fishing trawlers leaving from and returning to these fish landing stations and collected information on species wise total catch and duration of time spent in fishing. Data generated by Gopi et al. (2002) during the experimental trawling conducted in offshore areas close to the Gahirmatha coast (Zone I) and along the Paradip port (Zone II) (Fig. 1) was used to quantify the value of catch in mangrove and non-mangrove areas. The details of the zones and the trawling efforts were as follows:

Zone I: The Gahirmatha coast (zone with mangroves) is one of the largest rookeries for the Olive ridley sea turtle (Lepidochelys olivacea). The length of this zone is 35 km, it forms the eastern boundary of the Bhitarkanika Wildlife Sanctuary. In this zone 12 experimental trawling were carried out. The trawling depth varied from 6 to 10 fathoms (mean 7.72 ± 0.208). The duration of trawling varied from 1 to 2 h (mean 1.24 ± 0.109). The trawling distance varied from 3.39 to 14.36 km with a mean of 6.68 ± 0.934 and the distance from nearest shore line was 0.77 to 23.48 km with a mean of 5.85 ± 1.985.

Zone II: The Paradip coast (zone without mangroves) stretches for 55 km. In this zone, 29 experimental trawling were carried out. The trawling depth varied from 5 to 20 fathoms with mean value 10.13 ± 0.47. The duration of trawling varied from 1 to 2.15 h (mean 1.21 ± 0.065). The trawling distance in zone II varied from 1.7 to 8.8 km with a mean of 4.4 ± 0.29 and the distance from nearest shoreline was 0.43–14.07 km (mean 4.9 ± 1.08).

The value of catch in zones with mangroves and without mangroves was compared using Market Price method (IIED 1995; Wilson and Carpenter 1999; de Groot et al. 2002). On the basis of the market price of the catch, the catch was classified into three classes, A, B & C. A class catch included shrimps and fish that cost above US$ 1.25 kg−1 such as Ilisha elongata, I. melastoma, Parastromateus niger, Sphyraena barracuda, Euthynnus affinis, Rastrelliger kanagurta, Pampus argenteus, P. chinensis and Metapenaeus and Penaeus species. B class catch cost between US$ 0.6–1.25 kg−1 such as Liza parsia, L. tade, Mugil cephalus, Mene maculata, Harpodon nehereus, Scatophagus argus and Scylla serrata, Portunus pelagicus, P. sanguinolentus while C class catch cost below US$ 0.6 kg−1 such as silver bellies Gazzaminuta, Leiognathus species, bulls eyes Priacanthus cruentatus and mollusks among others.

Valuation of catch

The value of the catch was estimated by comparing the price of various fish species in local market using market price method following Wilson and Carpenter (1999) and de Groot et al. (2002). Market price is the exchange value that ecosystem services have in trade, mainly applicable to the ‘goods’ i.e. production functions, but also some information functions (e.g. recreation) and regulation functions (de Groot et al. 2002; Patterson 2002). These are often more readily accepted by decision makers as they are generally easy to observe, both at a single point and over time and reflect the decisions of many buyers (Dixon and Sherman 1991; Bann 1998). Thus we derived the value of catch using the formula: Total value of the catch = Unit market price × Quantity caught.

Results

Socioeconomic status of local people

The agroecosystem of BCA consists of 247.92 km2 of human habitation, village wood lots and agricultural fields. The local people in the area depend on non-mechanized agriculture characterized by small land holdings dependent on the monsoon. The local people have low per capita income as few opportunities for small-scale industries exist due to the lack of infrastructure facilities. Many people are working as skilled and unskilled laborers in other states. The average family income is US$ 603 annum−1. The number of years of education as well as of employment available to the villagers is highest in the villages that are located farthest away i.e. more than 3 km away from the National Park boundary while it is the lowest for the villages that are adjacent to the National Park boundary. The mean family income is lowest and the number of unemployed people is highest in the villages nearest to the National Park (Table 1).
Table 1

Economic characteristics of villages situated at different distance categories from the mangrove forests in the Bhitarkanika Conservation Area, East Coast of India (n = 324)

Village characteristics

Distance categories

0–1.5 km (n = 150)

1.5–3.0 km (n = 84)

>3.0 km (n = 90)

Mean

SE

Mean

SE

Mean

SE

Number of years of education

4.7

0.29

6.643

0.48

7.2

0.46

Months of employment

5.97

0.33

6.25

0.41

6.71

0.42

Family income (US$ year−1)

460.35

44.89

717.75

92.23

630.69

112.63

% people unemployed

16.00

14.29

10.0

Contribution of forestry products to local livelihoods

The use of the mangrove forests by the local people ranges from timber, poles and posts to fuel wood and fiber. Though the area has protected status and legally no extraction is permitted, the villagers living in mangrove areas are poor and depend on the mangrove resources for their livelihood. Table 2 enumerates the various use values derived from Bhitarkanika mangrove forests by the local people. In the BCA almost all the household used fuel wood, farm refuse and cow dung for cooking. Total requirement of fuel wood for cooking in the 36 villages was 2,205 ± 104.2 kg household−1 annum−1 (Table 3). An overall 14.2% of the fuel need of each of the household was being met by the forests with a mean consumption of 312 kg wood annum−1 (Table 3).
Table 2

Specific uses of various mangrove and non-mangrove* species of Bhitarkanika Conservation Area, East Coast of India

Specific use

Poles

Species

Rafters and supports

Beams/Bars

Connectors

Timber

Heritiera fomes

Phoenix paludosa

Avicennia spp.

Ceriops tagal

 

H. littoralis

 

Bruguiera gymnorrhiza

P. paludosa

 

Cynometra ramiflora

  

Heritiera spp.

 

Avicennia spp.

   

Fuel wood

C. tagal

   
 

Bruguiera gymnorrhiza

   
 

Heritiera spp.

   
 

*Tamarix dioica

   
 

*Hibiscus tiliacea

   

Thatching

*Phoenix paludosa

   

Fodder

Avicennia spp.

   
 

Myriostachya wighitiana

   

Weaving material

M. wighitiana

   

Medicinal species

 

Medicinal values

  
 

Heritiera fomes

Cuts/Bruises

  
 

Xylocarpus granatum

Oil (anti diarrhoeal)

  
 

*Pongamia pinnata

Oil (cure for skin diseases in human & cattle)

  
 

*Diospyros melanoxylon

Stomach ailments

  
 

*T. dioica

For neutralizing the poisonous latex of Excoecaria spp.

  
 

*Strychnos nux-vomica

Multiple uses

  

Honey

C. tagal

   
 

Sonneratia apetala

   
 

Aegiceras corniculatum

   
 

Amoora cucullata

   
Table 3

Dependency of local people on the Bhitarkanika mangrove forests, East Coast of India (n = 324 household)

Resource

Uses

Mean quantity (kg household-1 annum−1)

Monetary value (US$ household-1 annum−1)

Fuel wood

Total consumption of fuel

2205.0 ± 104.2

88.34

Fuel wood from Park

312.0 ± 32.2

12.5

Fuel wood from homesteads

21.0 ± 23.5

0.84

Cow dung and farm refuse

1949.0 ± 375.0

Fish

Fish caught from the Park

98.0 ± 28.3

68.6

Timber

Used as rafters

343.0 ± 36.9

15.6

As roof supports

27.0 ± 4.3

4.5

NWFP

Honey

525.0 ± 239.7

3.6

 

Thatching materials (P. paludosa)

49.0 ± 8.7

2.5

Although the use of timber from the forests has decreased since its declaration as a PA, people still use wood from the mangrove forests for making furniture and as beams and supports for the interior of the houses. Species belonging to genus Avicennia, Bruguiera, Phoenix, Heritiera are commonly used for columns, beams, and roof frames. Mangrove timber is extracted on a small scale in many areas for jetty construction, forest pathways, and small bridges. It is also used for boat building, fish traps, and mooring poles. Around 27 ± 4.3 kg household−1 annum−1 wood was consumed for roof supports (Table 3). The leaves of Phoenix paludosa stacked together in bundles of 13–20 serve as shingles for thatching purpose.

Among non-wood forest products (NWFP), honey is collected by the people largely to sell in the market. One of the mangroves associates Myriostachya wighitiana is used for weaving baskets, mats and other articles. In absence of any worthwhile pastures in the BCA a large livestock population is dependent on the forests. The cattle are left to graze in the fields in the fallow seasons. During the cropping seasons i.e. July–December, they are either stall-fed or are grazed in the forest. The value of forestry and fishery products harvested by the local people was estimated at US$ 107 household−1 annum−1 (Table 3).

Villages located near the forest areas were found to use more fuel wood and timber. A significant difference was found between the mangrove fuel wood consumption in the three distance categories (F = 36.179, df = 2, p = 0.000). There was a distance wise variation in income from fishing. The highest income from fishing was for the villages within 1.5 km from the PA boundary (US$ 26.09 ± 5.79 annum−1) followed by villages located at 1.5–3.0 km (US$ 16.69 ± 15.12) and <3 km (US$ 10.31 ± 8.91; Table 4). Though no significant difference was seen in the quantity of fish harvested between the villages in the three categories (F = 0.470, df = 2, p = 0.625), a significant difference was seen for the incomes derived from the same (F = 0.788, df = 2, p = 0.456). Highest consumption of thatching material was seen for villages in the adjoining areas of forests while the villages situated at more than 3 km away from the forests did not use this resource. A significant association (F = 10.942, df = 2, p = 0.000) between distance of the village from mangrove forests and consumption of thatch was found (Table 4).
Table 4

Resource use by villages located at different distance categories in the Bhitarkanika Conservation Area, East Coast of India (n = 324 household)

Resource use (100 kg household−1 annum−1)

Distance from BCA 0.0–1.5 (n = 150)

Distance from BCA > 1.50–3.0 (n = 84)

Distance from BCA > 3.0 (n = 90)

Mean

SE

Mean

SE

Mean

SE

Fuel wood from the Park

580

53

83

.25

82

50

Wood used as rafters

456

50

249

53

242

88

NWFP used for thatching

90

16

27

15

0.00

0.00

Wood used as supports

43

8.0

21

7.0

5.0

3.0

Honey

1.0

0.00

0.00

0.00

0.00

0.00

Fish catch from the sanctuary

125

39

94

65

60

49

Income from fishing (US$ household−1annum−1)

26.1

5.79

16.69

15.12

10.31

8.91

Contribution of fish and shellfish production to local livelihoods

Of the 25 species of fish reported from BCA (Chadha and Kar 1999), 12 species were caught during the sampling. Of these Estuarine catfish (Mystus gulio), Gangetic koi (Anabas cobojius), Yellowtail catfish (Pangasius pangasius) and Giant catfish (Arius thalassinus) were the most common species. The highest catch was for Mystus gulio (1.4 kg h−1) followed by Anabas cobojius and Pangasius pangasius. The total catch was 3.77 kg h−1 having market price of US$ 2.25 (Table 5). The mangrove snapper Lutjanus species which is occasionally caught by the local villagers was not caught during our sampling. Lutjanus species inhabits sheltered lagoons and exposed outer slope of coral reefs and are occasionally reported from the BCA that lies at the northern margin of its distribution range.
Table 5

Fish and shellfish catch and their market price in Bhitarkanika Conservation Area, East Coast of India

Common name

Scientific name

Market value (US$ kg−1)

Catch (kg h−1)

Earning (US$ h−1)

Exploitable species

 Gangetic koi

Anabas cobojius

 

0.90

0.52

 Flat head mullet

Mugil cephalus

0.75

0.05

0.04

 Hilsa

Tenualosa ilisha

1.45

0.01

0.01

 Giant catfish

Arius thalassinus

0.55

0.16

0.09

 Estuarine catfish

Mystus gulio

0.45

1.40

0.63

 Yellow tail catfish

Pangasius pangasius

1.12

0.70

0.79

 Golden threadfin

Polydactylus sexfilis

0.5

0.17

0.08

 Gray mullet

Liza tade

0.95

0.04

0.04

 Grenadier anchovy

Coilia borneensis

0.60

0.05

0.03

 Puffer fish

Tetraodon hispidus

0.12

0.10

0.01

 Spotted scat

Scatophagus argus

0.62

0.07

0.04

 Yellow threadfin

Arius arius

0.5

0.01

0.005

 Mud crab

Scylla serrata

0.5

0.11

0.05

 Total catch h−1

3.77

2.25

Shellfish seedlings

 White prawn

Penaeus indicus

65.30

0.2–1.2

0.16–0.82

 Tiger prawn

P. monodon

5.90

0.1–1.5

0.06–0.09

 Mud crab

S. serrata

14.80

0.5–1.0

0.07–0.15

 Total catch h−1

 

86.0

0.09–0.35

Juveniles of 11 species of fish, two species of prawn Penaeus species and mud crabs Scylla serrata were recorded during the sampling. Of these, only three species are commercially exploited. These were Penaeus indicus, P. monodon and S. serrata. The price of these species varied for P. indicus US$ 0.2–1.2/100 seedling, for P. monodon US$ 0.1–1.50/100 seedling and for S. serrata it was US$ 0.5–1.0/100 seedling. From these, earning ranged between US$ 0.06–0.82 h−1 (Table 5).

The limited sets of data generated during this study restricted us from predicting an accurate model for off shore fisheries. However, our data suggests that the number of species caught exclusively at Zone I which is nearer to the mangrove, are greater (19) as compared to Paradip coast (Zone II) where exclusively five species were caught. Twenty-five species were common to both the zones. There was a significant difference in total catch between both the sampling sites. Zone I (with mangrove) has considerably high fish yield, 123.34 kg h−1 than Zone II (without mangrove), where the yield was 17.89 kg h−1. Hence, the earning was US$ 44.62 h−1 in Zone I, while it was only US$ 2.62 h−1 in Zone II (Table 6).
Table 6

Comparison of off shore fishery production at Gahirmatha and Paradip coasts, East Coast of India (*A class catch costs above US$ 1.25 kg−1, B class catches costs between US$ 0.6–1.25 kg−1 and C class catch costs below US$ 0.6 kg−1)

Fish class*

Gahirmatha coast (Zone I)

Paradip coast (Zone II)

Rate (US$ kg−1)

Catch (kg h−1)

Earning (US$ h−1)

Rate (US$ kg−1)

Catch (kg h−1)

Earning (US$ h−1)

A—Class

1.28

15.78

20.19

1.39

0.24

0.33

B—Class

0.37

43.93

16.48

0.39

0.31

0.12

C—Class

0.12

63.63

7.95

0.12

17.35

2.17

Total

123.34

44.62

17.89

2.62

Discussion

The study reveals a high degree of resource use by local people despite the protected status of the Bhitarkanika mangrove forests. Conservatively estimated, the resources extracted from the mangrove forests contribute more than 14.5% to the total income of the households on an average, and for the poor and marginalized households residing in the immediate vicinity of the mangrove forests this proportion was more than 30% (Badola and Hussain 2003). Since people living nearest to the mangrove forests have fewer years of education, employment and income, their dependence on mangroves is also the highest. The pattern of consumption of fuel wood, construction materials and fish products decreased with increasing distance from the park. In the area, people are less dependent on the mangroves for fuel wood as they procure it from the market or from the trees in the homesteads. A heavy dependence (88.4%) was observed on cow dung cakes and farm refuse as other sources such as Liquefied Petroleum Gas (LPG), kerosene or coal are not easily available. Because of durability, the timber from P. paludosa, Avicennia and Xylocarpus species were extracted occasionally. However, the shingles or the thatches made of P. paludosa have to be replaced every second or third year.

Fishing is the primary source of income for the majority of the people residing in the BCA. Seedlings of P. indicus, P. monodon and S. serrata were collected by children and women folk and sold to aquaculture ponds while some such as P. chinensis and M. cephalus are commercially exploited. Edible crabs are extracted in large numbers by the fishermen both in the breeding and non-breeding seasons. These observations highlight the relative importance of estuaries and mangroves as the nursery ground for fish and shellfish as well as their importance for the sustenance of the local people.

Sathirathai and Barbier (2001) estimated that annual value of local villagers collecting mangrove products was US$ 88 ha−1, which was US$ 107 households−1 annum−1 in the BCA. In this part of India where the family income is US$ 603 annum−1 a large number of people live on less than one dollar a day, the contribution of mangrove forests to local livelihoods becomes important. However, this may not have the same significance in developed countries with high incomes (Hussain and Badola 2008). It is therefore important that the income provided by mangroves should not be ignored simply because it is not accounted for in national statistics.

Many coastal communities in the tropics are characterized by relative geographic isolation, chronic poverty and significant dependence on the harvest of marine and coastal resources (Kunstadter et al.1986). Majority of the people living in or near mangrove forests derive their principle income from fishing and related activities (Islam and Haque 2005). The direct harvest of mangrove products is rarely a full-time occupation for them, but many rely on these products to meet subsistence needs. For others, the harvest and sale of mangrove products is an important income supplement (Christensen 1982; Kunstadter et al.1986; Diop 1993; Spalding et al. 1997; Lacerda 2002; Glaser 2003; Walters 2005). For the poor rural families, mangrove products have an emergency food provision function and constitute the main source of protein in their diet (Magalhaes et al. 2007). The social welfare of the traditional sector depends heavily on non-monetary income or in-kind services provided by the undeveloped mangrove areas (Nickerson 1999).

In the Sundarbans, important products from the mangrove area include Nypa fruticans which is used for sugar, alcohol production, and thatching and honey which is both a food and economic stimulus (Basit 1995). Sathirathai and Barbier (2001) have estimated that honey collection contributed US$55 household−1 annum−1 in southern Thailand. Similarly, the contribution of subsistence fisheries to total catch supported by mangroves was estimated 10–20% in Sarawak (Bennett and Reynolds 1993), 56% in Fiji (Lal 1990), and 90% in Kosrae (Naylor and Drew 1998).

These indicative results suggest that contribution of mangrove forests is of significant economic importance, as it increases the resilience and sustainability of the local economy. Recognition of this is important in the present scenario where large-scale removal and degradation of mangroves has already taken place. Our study highlights the need for more research both on the productivity of the mangrove-dependent systems and their contribution to the local economy. This must be complemented with further study of the impact of incremental changes in the ecosystems and their productivity due to reduced river flow, overuse, pollution, and other pressures. Such studies are useful for better understanding of goods and services provided by mangroves. This may influence the awareness and perception of the local people as well as the policy makers and would go a long way in eliciting support for the conservation of mangrove ecosystems.

Acknowledgments

The India Environment Management Capacity Building (EMCaB) Project, Indira Gandhi Institute of Development Research (IGIDR), Mumbai provided funding support for this study. We thank Chief Wildlife Warden, Government of Orissa for permitting us to carry out this research in the N.P. Bhitarkanika. We thank Dr. Hemant Kumar Sahu, Ms. Poonam Semwal, Ms. Kalpana Ambastha, Ms. Shivani Chandola and Mr. K.R. Anoop for assisting us in field data collection. Ms. Ashi Qureshi and Ms. Pariva edited the manuscript.

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© Springer Science+Business Media B.V. 2010