Department of Botany, Faculty of science, Eastern University, Chenkalady, Sri Lanka
Author
Correspondence author
International Journal of Marine Science, 2014, Vol. 4, No. 55 doi: 10.5376/ijms.2014.04.0055
Received: 26 May, 2014 Accepted: 13 Jul., 2014 Published: 11 Oct., 2014
This is an open access article published under the terms of the
Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Mathiventhan and Jayasingam, 2014, Coastal green belt in Batticaloa district, Sri Lanka: Is Casuarina a success?, International Journal of Marine Science, Vol.4, No.55 1-5 (doi: 10.5376/ijms.2014.04.0055)
Coastal barriers are established for protection. Casuarina, a fire prone species, has been popular in Batticaloa district, Sri Lanka, planted as coastal barrier (belt), especially after the tsunami in 2004. The overall extent of Casuarina plantation is about 400 ha, as monoculture. About 52% of belt was established after the tsunami. About 40-50 km of Casuarina belt has been established in the 65 km of the coast line from Periyakallar to Kalkudah/Pasikudah which accounts for 35-40% of the coastline of Batticaloa district. Casuarina plantation starts at 50-75m from mean high tide. The distance between patches varies from 50-400 m. A density of 1600 to 3000 plants/ha has been maintained. Field evaluation showed only 50-60% of Casuarina has been succeeded; 40-50% shown poor growth or damaged/disturbed owing to many reasons such as illegal activities, less awareness, financial and management problems. Casuarina does not permit ground growth, resulted in low bio-diversity. However, the belt protects vegetable crops from salt spray and “burning” of leaves. This plantation has other social aspects to consider beyond the protection such as sand mining, garbage dumping, etc. When assessing both positive and negative aspects of Casuarina plantation in Batticaloa, failures are more in socio-ecological point of view, even though Casuarina physically developed in a reasonable manner.
Bio-shields are generally defined as planting vegetation belt along coastlines, which protect the inland from coastal storms, waves, tsunami and cyclones. They are considered low cost disaster mitigating option when compared with hard solutions (IUCN, 2007). Some of them are mangroves, coral reefs, sand dunes, Casuarina and coastal home garden which have different degree of protection to the coastal areas. In Sri Lanka, the importance of coastal protection had been realized after severe impacts of 2004-tsunami (Zoysa, 2008). This was reflected in the establishment of Casuarina plantation along the coast of Batticaloa district. It was mainly carried out by the Forest Department (FD) and an NGO “Mandru”. Casuarina plantation was established with minimum technical and scientific inputs in Batticaloa district. Establishment of coastal green belt is a crucial effort that needs careful planning, scientific and technical inputs. A sustainable coastal green belt development needs to include the following conditions such as suitable species that tolerate xerophytic conditions, multiple species composition, adequate spacing between belts and individual plants, fire belt, eco-social friendly approach and sustainable management practices. This study was planned to find out present scenario of existing coastal Casuarina belt in terms of ecological and social point of views.
1 Results
1.1 Area of study
Batticaloa district has 8 coastal DS divisions among the 14 DS divisions. Casuarina plantation had been found in 5 DS divisions among the eight coastal DS divisions (Table 1). Casuarina plantation was established in the name of “coastal casuarina plantation” and “coastal bio shield”.
1.2 Implementation of Casuarina plantation
The plantation was established in 372 ha by having 987,000 numbers of plants. Forest Department (FD) and “Mandru”, an NGO, were the two major implementing agencies involved. Twenty five percent (90 ha) of Casuarina plantation had been established by the FD and 75% (282 ha) by the “Mandru” (Table 1).
Table 1 Details of Casuarina plantation in the coastal areas of Batticaloa district(DSD-Divisional Secretariat Division, GND-Grama Niladhari Division, FD-Forest Department, MSEP-Manmunai South & Eruvil Pattu, MP- Manmunai Pattu, MN-Manmunai North, EP-Eravur Pattu, KP- Koralai Pattu)
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These projects focused on 5-6 months for implementation and 12-18 months for continuous management. About 40-50 km of Casuarina belt has been planted in the 65km of the coast-line between Periyakallar and Kalkudah/Pasikudah (Figure 1). This account 35- 40% of the coastline of Batticaloa district and 70% of the study area. Majority of the plantation had been established between the year 2000 and 2005. About 52% (210 ha) of the belt was established after the 2004-tsunami.
Figure 1 Illegal cutting (A), burning (B) of and garbage dumping (C) in the Casuarinaplantation
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1.3 Ecology of plantation
Casuarina equisetifolia used as a monoculture species. The Casuarina plantation starts at a distance of 50-75m from mean high tide mark and the width was 75-100 m. The belt is contiguous in some places and discrete in others. The gaps between the Casuarina belts existed unequally, ranges from 50-100 m in some places and 300-400 m in others.
The age of the Casuarina trees were between 4 and 8 years and the height ranges between 2and15 m. Casuarina belts that were established before tsunami reached up to a height of 12-15 m. A density of 1600 plants/ha has been maintained by FD and 3000 plants/ha by Mandru. Debris and fallen leaves of Casuarina accumulated on the ground, for about 7-12 cm thickness and covered the entire area of the belt, which was not removed.
1.4 Present situation
Many of the places, Casuarina belt was established at a satisfactory level. At the same time illegal cutting of trees was a common problem noted in all the sites, for the purpose of agriculture farming, fencing, fire-wood and home garden activities. In addition to that, Casuarina trees burned due to personal issues in certain places (Figure 1). Sand mining and garbage dumping also noted in some places in the vicinity and inside the plantation.
About 26% of Casuarina plantation had been lost (Table 2) and 50-60% of the plantation succeeded. The rest of the plantation showed poor growth. Casuarina which established in 2003 and 2005 showed higher percentage of loss.
Table 2 Loss of Casuarina, planted at different time period. Planting activities not continued after 2006
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2 Discussion
2.1Selection of species
Casuarina tolerates xerophytic conditions and shows reasonable establishment within a period of 6-7 years, in a height of 10-15m. But it was monoculture. Monoculture stands are more vulnerable and less resilient than multi-species for external shocks (Adger et al., 2005). It does not permit ground growth within the plantation area (Zoysa, 2008) due to thick litter layer, shadow effect and may be possible physiological effects on the other species. This leads low biodiversity. When considering species combination, the Casuarina belt is less successful. This plantation could be designed in a way to accommodate natural succession of other coastal plants such as Pandanas, Spenifex, Ipomea, Calotropis, etc. Careful planning and suitable selection of species should be focused when projects are designed. It is advisable to use multi-story-multi-species with adequate multi-disciplinary approaches when considering any restoration or establishment of ecosystems. The above would accommodate as many as functional groups and are necessary for the continued development and stability of the restored ecosystem (Clewell et al., 2004; Andel and Aronson, 2006). Therefore, selection of suitable species depends on identifying similar and suitable reference sites and the history of the area where the project is going to be implemented. This is the crucial and indispensable part in the designing phase.
2.2 Fire belt
Casuarina is a fire prone species. Spaces between belts and individual plants were 50-400 m and less than 2m respectively in most of the places. In addition to that, litter was found to be 7-12 cm thickness. No fire-belt established in any of the plantation site. Accidental fire leads severe damage for the planted Casuarina belt and it was happened in one of the sites. When considering these issues, Casuarina belt was not scientifically designed in Batticaloa district. The gaps between belts and individuals should be maintained effectively. But in the case of tsunami the gaps are less protective for the incoming waves. By establishing another vegetation layer in front of or behind the Casuarina belt, especially to cover the gaps between Casuarina belt, could be analternative approach to reduce the tsunami waves (Samarakoon et al., 2012).
2.3 Funding sources and alternate income support
Funding is the main limiting factor for the agencies for its continuity and managing the programme in a long-term. Technical capacities of government and non-government agencies for bio-shield implementation should be enhanced/increased. Fund raising programmes could be an alternative by the local people. Alternative livelihood activities should be focused when designing bio-shield programme, in the form of “bottom up approach”. This should make room for financial circulation or income generation among the local communities which lead sustainable management. This part was designed in the early phase of planning but it was not successfully met, due to financial restrictions.
2.4 Agriculture farming
Casuarina belt acts as a barrier for wind blow and salt spray. It facilitates agriculture and home garden practices from falling and burning of crops, especially in Kaluthavalai and Tettathivu. But at the same time, excessive shadow effect caused less performance of crops when the agriculture farm closes to the Casuarina belt.
2.5 Community access
Fishermen appreciated that adequate space left for fishing activities and shade was utilized by them for resting and repairing nets. There were no conflict of interest found between the fishermen and the implementing agencies. Public appreciated because it is believed to protect from natural hazards, provides scenic beauty and leisure. In this point of view the Casuarina belt is designed in an eco-social friendly manner.
3 Conclusion
Species selection is an important when planning restoration of ecosystems. Local knowledge, reference sites and history of the site are also indispensable. One of the key features of coastal green belt or bio-shield development is to allow the area without any disturbances for natural succession or activities that support the natural succession. In assessing the success of plantation, positive and negative impacts need to be considered as indicated above. This emphasis on a proper scientific planning (Feagin et al., 2010). The question remains “whether is it worthwhile to establish such a green belt focusing on a future, unpredictable natural catastrophes given the existing eco-social problems over a longer time frame?”
4 Materials and methods
4.1 Study area
The length of coastal region of Batticaloa district is approximately 102 km. All the coastal areas that having Casuarina plantations, in the Batticaloa district, were selected, which lies between Periyakallar and Kalkudah/Pasikudah (Figure 2). Coastal area in this study was defined within 300 m from mean high tide mark (CCD, 2004).
Figure 2 The location of Casuarina plantation (study sites) along the coast of the Batticaloa district
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4.2 Data collection
The following information was obtained by means of field survey as well as by using semi-structured questionnaire. (1) Administrative: name of DS and GN divisions, name of the project implemented, year of implementation and name of the implementing/partner organizations. (2) Ecological: name of variety used, extent, height, number of plants, present situation. (3) Opinions from various stakeholders.
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IUCN, 2007, Technical guidelines for the establishment of a coastal greenbelt
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Zoysa M.D., 2008, “Casuarina Coastal Forest Shelterbelts in Hambantota City, Sri Lanka: Assessment of Impacts”, Small-scale Forestry, Vol. 7, pp 17-27
http://dx.doi.org/10.1007/s11842-008-9038-2