Survey & documentation of Mangroves in Coastal

CHAPTER-5 MANGROVE CONSERVATION: PROBLEMS AND PROSPECTS

Mangroves grow well in the intertidal regions along the estuaries, backwater islands and other areas sheltered from strong wave action. They prefer silt to silty clay and sandy clay for their growth. Different mangrove species have different tolerance ranges for salinity of the habitat. Indian mangroves underwent drastic decline and degradation during the last century. The major reasons for the decline of mangroves, especially along the central west coast, including that of Karnataka are:

5.1 Problems and Prospects 5.1.1. Over-exploitation or deforestation of mangroves for fuel and fodder The coastal tract of Karnataka, barring certain parts of Uttara , is away from forests. It is also densely populated region. There is high density of population especially in fishing villages and insufficiency of plant resources to meet fuel and fodder needs. Mangroves often become easy target for firewood extraction and are to some extent lopped for fodder, particularly Avicennia spp. (Figure 5.1).

5.1.2. Reclamation of mangrove swamps Human habitation agriculture and horticulture in substantial areas along the coast, from pre-historical times, came up in reclaimed estuarine areas. The gazni rice fields of were formerly mangrove swamps. Reclaimed mangrove swamps are good for coconut gardens. Shrimp farming has become a rampant activity along the mangrove areas in recent times causing considerable destruction of mangroves (Figure 5.2)

5.1.3. Sand and shell mining There is enormous demand for river sand for construction activities. Sand removal from the rivers cause deepening of the river bottom and has adverse consequences on mangrove habitats. Removal of clamshells in huge quantity is undertaken in and Kali estuaries. Shell mining areas become unfit for recolonization by mangroves, at least for some years (Figures 5.3, 5.4)

5.1.4. Grazing and trampling by livestock Buffaloes particularly feed on leaves of Avicennia spp., Cyperus malaccensis and Cynodon dactylon (Karki grass). Buffaloes easily walk through as well as swim in the backwaters to reach mangrove and grass areas, causing particularly harm to mangrove saplings, both natural and planted (Figure 5.5)

5.1.5. Damages to saplings from native crafts and fishing activities As the local fishermen who operate native crafts moor their boats on estuarine banks, as well as drag them through shallow swamps, in their routine fishing operations, they find mangrove afforestation as an impediment. This can be easily overcome by awareness creation and by providing gaps in mangrove planting in consultation with the local people.

5.1.6. Bund and road making Considerable stretches of riverbanks are protected with stone embankments, to prevent bank erosion. The embankments along river or estuarine banks do considerably reduce intertidal zone, the prime habitat of mangroves. Roads, permanent and temporary bunds are made around shrimp farms, also causing much reduction in mangrove vegetation (Figure 5.6).

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Earlier, the farmers of Aghanashini estuary used to plant mangroves alongside the earthen bunds of gazni rice fields. That practice has been discontinued ever since the Government constructed permanent stone bunds. However some farmers, aware of the importance of mangroves do plant maintain them. At Hangallur in Kundapur a shrimp farmer has raised excellent mangrove fortified bund around his farm.

5.1.7. Dumping of rubbish and solid waste into the swamps As estuarine villages and most coastal towns do not have proper solid waste disposal mechanisms the waste is dumped into the nearest estuarine areas or river banks adversely affecting the ecosystem as a whole (Figure 5.7)

5.1.8. Impact of dams and barrages Activities upstream that alter fresh water influx into the estuaries can adversely affect mangroves. The construction of hydel projects in Sharavati river is followed by constant release of fresh water after the power generation. Since the tidal flow into the Sharavati estuary is not strong enough due to sand bar at the mouth the considerable fresh water inflow has substantially altered the mangrove vegetation. The mangroves associated with higher salinity, such as Rhizophora spp., Avicennia marina, Sonneratia alba etc. have vanished almost totally. On the other hand the fresh water tolerant Kandelia kandel, Avicennia officinalis, Soneratia caseolaris etc. have increased, along with rich growth of the sedge Cyperus malacensis.

The recent construction of barrages for storing fresh water, in the Chakra and Kollur rivers in the coastal taluk of Kundapur, has caused massive death of mangroves in the upstream areas (Figures 5.8-5.10).

5.1.9. Insects, pests, disease and other problems The forest officers of Honavar Division reported about seedling mortality from barnacles and oysters attaching to them, insect pests, deposit of dense mat of algae over the seedlings/saplings as well as eating of propagules by mollusks. Cattle grazing, especially by buffaloes, and human activities, such as fishing, rowing or dragging of boats through plantlings in a plantation, shell and sand mining, soil erosion and sedimentation etc. are detrimental to mangroves. Untawale (1997) recommends planting of mangrove grass Porteresia coarctata for stabilizing mudflats, on which later mangroves may be planted. Otherwise young plantations on mudflats are prone to be washed out.

Environmental Management & Policy Research Institute 38 Survey & documentation of Mangroves in Coastal Karnataka

Figure 6.1. Mangrove cutting for Figure 6.2: Shrimp ponds in Figure 6.3. Clam shell domestic use transportation, Aghanashini estuary

Figure 6.4. Damages from shell Figure 6.5. Buffalo feeding on Figure 6.6. Bund making through mining in Kali river mangroves Kali mangroves

Figure 6.7. Disposing waste in Figure 6.8. Barrage in Kollur Figures 6.9. Scenes of mangrove Kali swamp river death following barrage construction in upstream of Kollur river

Figures 6.10. Scenes of Figure 6.11. High density mangrove death following planting in Aghanashini estuary, Figure 6.12. Mangroves raised barrage construction in upstream Kumta by a shrimp farmer at of Kollur river Hangallur, Kundapur taluk

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5.2 Mangrove afforestation in Honavar Division The first effort, rather symbolic, at mangrove afforestation was carried out with people’s participation, by the Centre for Ecological Sciences of the Indian Institute of Science, Bangalore. From 1988 onwards, consecutively for 3 years the CES raised mangroves, mainly R. mucronata, in a field nursery adjoining the Kagekan mangrove patch of Masurkurve Island. Almost 2500 propagules were planted every year alongside Masurkurve as well as in Masur-Lukkeri areas. In the absence of follow up work we do not know how many of these mangroves survived. The CES planting created some awareness among the villagers, and paved the way for more successful mangrove afforestation schemes of the Forest Department (P.R. Bhat, personal communication).

Details of mangrove afforestation carried out by the Forest Department in the various estuaries are given in the Tables 5.1-5.4.

Table- 5.1: Details of mangrove planting in the Sharavati estuary of Honavar taluk Year Range Localities No. Name of scheme planted 2001-02 Honavar 82,000 Coastal Shelter Belt 2005-06 Honavar Kasarkod 2,25,000

Table-5.2. Details of mangrove planting in the Gangavali estuary of Kumta-Ankola taluks Year Range Localities No. planted Name of scheme 2001-02 Gangavali 1,00,000 Coastal Shelter Belt; Conservation & river bed Management of Mangroves -do- -do- 1,00,000 2003-04 -do- Moralli, 45,000 Conservation & Development of Mogta, Andle Mangroves -do- Juga, Ulware 45,000 2005-06 -do- Gangavali 50,000

Table 5.3. Details of mangrove planting in the Aghanashini and Alvekodi estuaries of Kumta taluk Year Range Localities No. planted Name of scheme 2000-01 Kumta Masur 50,000 Coastal Shelter- Belt Lukkeri 50,000 Baad 50,000 50,000 Aghanashini 97,000 Conservation & Management of Mangroves 2001-02 -do- Masur-Lukkeri 73,000 Coastal Shelter-belt Baad-Kagal 50,000 Aghanshini river bed 1,83,000 Conservation & Management of Mangroves 2002-03 Kumta Masur-Lukkeri 3,03,000 ADB assisted KUDCEM Project Hiregutti Bargi-Gund 50,000 Gund-Betkuli 50,000 2003-04 Kumta Alvekodi 16,300 Conservation & Management of Kagal-Baad 37,500 Mangroves Kagal-Masur 37,500 Masur-Lukkeri 37,500

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Year Range Localities No. planted Name of scheme Lukkeri-Hegde 37,500 Alvekodi 37,500 Katgal Paduvani 51,000 Hiregutti Bargi Gazni-Moraba 45,000 2004-05 Kumta Masur-Lukkeri 1,50,000 Lukkeri-Hegde 37,500 Lukkeri-Baad 37,500 Kalbag-Alvekodi 25,000 Hiregutti Nushikote 3,50,000 2005-06 Kumta Lukkeri-Hegde 37,500 Alvekodi-Kalbag 37,500 Alvekodi-Kumta 25,000 Kumta-Alvekodi 37,500 Katgal Mirjan 2,20,000 Hiregutti Nushikotte-Moraba 9,00,000 Moraba 1,00,000 Bargi 2,50,000

Table- 5.4: Details of mangrove planting in the Venktapur estuary of Bhatkal taluk

Year Range Localities No. planted Name of scheme 2001-02 Bhatkal Venktapur 40,000 Coastal Shelter Belt river bed 2002-03 -do- Alvekodi 30,000 Coastal Shelter Belt; Conservation & Management of Mangroves 2003-04 -do- -do- 12,500 Conservation & -do- 16,300 Development of Mangroves -do-

5.3 EMPRI’s experimental studies on mangrove survival and growth The Environmental Management and Policy Research Institute (EMPRI) carried out some studies on mangroves. The first study was on estimating growth in height of 12 years old Rhizophora mucronata in three sample plots, each of 10X10 m area, in the Kundapur estuaries. The details are given in the Table 5.5.

Table 5.5: The growth in height (average) of Rhizophora mucronata at 12 and 13 years age, in three sample plots (10X10m) of Kundapur estuaries, under natural regeneration

Plot Location Species Nos Height (12 yrs) Height (13 nos May -04 yrs) Sept. 05 1 Someshwara Rhizophora mucronata 18 4 .00 mts 4.30 mts 2 Sampukudru -do- 16 4.50 mts 4.75 mts 3 Sampukudru -do- 18 4.40 mts 4.75 mts

5.3.1 Artificial propagation Artificial regeneration of Rhizophora mucronata was carried out in 2003 in part of the Netravati estuary at Sampu Kudru. The first step is collection of mature propagules. The second step consists of growing the propagules in a nursery on the estuarine bank. Silt from

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the estuarine bank was mixed with farmyard manure. Polythene bags of 5 x 8 inch size were filled with this mix. The polythene bags filled with the mix were arranged in the field nursery on the shore of the estuary. In the nursery sunken beds were prepared for this purpose. Ripened propagules collected from the trees were planted in the bags, one each. Watering was done for 4-6 months. The nursery raised 4-6 month old seedlings are suitable for planting. Data from a 2003 plantation is furnished in Table 5.6.

The table shows that under artificial regeneration there is higher degree of seedling survival and satisfactory rate of growth. However, it should be admitted that these observations need to be conducted periodically over a longer period.

Table 5.6: Data from 2003 plantation of Rhizophora mucronata at Sampa Kudru Plot Method of planting Av ht. Survival Av. ht on Av. ht. on Survival no while 18.5.04 % 18.5.04 % 31.8.05 % 31.8.05 % planting 1 R. mucronata plants raised in 22 cm 70% 48 cm 110 cm 64% 5X8 poly bags planted in pits in such a way that the plants are watered by the high tide naturally 2 -do- 24 cm 72% 46 cm 105 cm 61% 3 -do- 20 cm 70% 44 cm 110 cm 62% Note: Plot 1 while surveying last had 39 saplings, Plot 2 had 36 saplings and Plot 3, 37 saplings respectively. Some of the plants had been washed away by floods in Netravati river.

Table 5.7. Data from 2004 plantation of Rhizophora mucronata and Kandelia candel at Sampu Kudru Plot Species planted Nos Survival % Av ht while Av height No. survived planting on 31.8.05 I Rhizophora mucronata 34 63% 22 cm 55 cm II -do- 30 61% 22 cm 60 cm III Kandelia candel 28 60% 14 cm 57 cm Note: 1. The height measured is above ground level 2. The major reason for the casualty was the flood in the Netravati river

5.3.2 Results and discussion Mangrove vegetation is perhaps the most significant of the coastal plant communities. Mangrove swamps are known for their highest unit area productivity, ranking with the coral reefs. Mangroves enrich the estuarine ecosystems in biodiversity as well. They provide shelter for numerous species of birds, many of which are migratory. Recent times have witnessed tremendous decline of the mangroves due to human activities.

Our experiment shows that conditions of the Netravati estuary are still favorable for raising mangroves. The casualty of the saplings planted in Sampu Kudru was caused mainly by floods in the Netravati river. Nevertheless, over 60% survival is very encouraging. Moreover, the growth rates of the saplings are also very satisfactory, and in the next one or two years they will become entirely flood tolerant.

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References 1. Anonymous, 1992. Coastal Environment. Space Application Centre (ISRO), Ahmedabad, pp 1-114.

2. Kothari, M.J. and Rao, K.M. 2002. Mangroves of Goa. Ministry of Environment and Forests, Botanical Survey of , Kolkata.

3. Macnae, W. 1968. A general account of the fauna and flora of mangrove swamps and prospects in the Indo-West Pacific Region. Adv. Mar. Biology, 6: 73-270.

4. Untawale, A.G. 1997. Restoration of mangroves along the central West Coast of India. In: Conservation Assessment & Management Plan (C.A.M.P.) Workshop for Indian Mangrove Ecosystem. Zoo Outreach Organization, Coimbatore.

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