Climate change mitigation through reforestation in Godavari mangroves in India Open Access

Sea‐level rising and increasing sea‐surface temperatures due to climate change are displacing coastal ecosystems like mangroves and tidal wetlands further landward (Christensen et al., 2007). But their landward migration is expected to be constrained by human infrastructure and human food production systems which will eventually lead to their disappearance. Mangrove forest is one of those coastal ecosystems that are threatened by this phenomenon and in Bangladesh already some 7,500 hectares of mangrove forest have been submerged over the past 30 years due to rising sea level (Huq et al., 1995, 1999). An United Nations Environment Programme (UNEP) study estimated that 13 per cent of mangrove forests in the Pacific islands could be lost and by the year 2100 half of these resources could be lost in the Pacific region due to sea‐level rise (Nguyen Dang Vu, 2006).

Coastal communities like fishers and subsistent farmers dependent on mangrove forests, are particularly vulnerable and their livelihoods will be seriously threatened. There is a need to protect and restore tidal wetlands that are threatened by sea‐level rise and increasing developmental activities along coastlines (Duke et al., 2007). For saving this ecosystem the UNEP has recommended planting new trees and increasing the mangrove habitat. This reforestation is mainly being done for improving local economy through increased environmental and social benefits. However, reforestation in mangroves has its shortcomings as seen in the Philippines where mortality of seedlings was high due to planting in biologically unsuitable areas (Malakoff, 2008). The mangrove plantations are slowly replacing the natural forests and local people are cutting them for economic benefits rather than conserving them for environmental protection (Walters, 2004).

The economic value of the goods and services provided by a hectare of mangroves is estimated to be between US$200,000 and 900,000 (Nguyen Dang Vu Long, 2006). For the Godavari Delta in India, this service was valued at US$2,700 per hectare, which extrapolates to approximately US$90,000 annually for the entire area (CORDIS, 2003). The mangroves in this delta have potential to support an estimated annual catch of around 50,000 tiger prawn (Penaeus monodon) spawners, valued at US$6 million (Rönnbäck et al., 2003). Similar worldwide observations were recorded by Roy “Robin” Lewis III from Florida, USA. He further added that involvement of landowners and political leaders might complicate the issue by ignoring the biology of mangrove trees. The changing global climate scenario leading to sea‐level rise is a potential threat to overpopulated coastal areas. It could endanger the livelihoods of mangrove‐dependent people in the developing countries. Mangroves are already in a threatened state due to several developmental activities in the Godavari Delta region in India and there is a need for restoration through reforestation and proper management. The Forest Department of the Government of Andhra Pradesh has started restoration of mangroves in 1991 by identifying degraded mangrove areas and digging canals in the Coringa area. The M.S. Swaminathan Foundation, a Chennai‐based NGO, had initiated a reforestation project from 1997 to 2004 with funding from India‐Canada Environment Facility. The project aimed at obtaining greater commitment by the forest department of the state in participation with the local communities for the Joint Mangrove Management (JMM) programme. The goal of the JMM is to enhance the capacity of the local communities to manage mangrove resources. The department is actively pursuing the restoration activities till date.

This study explores the extent of reforestation in the Godavari Delta area and its possible beneficial effects to mitigate climate change.

Godavari is the second largest river in India with a length of 1,530 kilometres, of which 770 kilometres flows in Andhra Pradesh and its river mouth is located on the east coast near Kakinada in the East Godavari district, south‐west of the port city of Visakhapatnam. The lower Godavari branches into Gautami‐Godavari and Vasishta‐Godavari. Over a period of a century, the Gautami‐Godavari branch, changed its main course further south and the earlier deltaic wetlands became mangrove mudflats. Gradually, due to silting activity and accretion, a sand bar was formed that separated the lagoon (called Kakinada Bay) from the sea (Figure 1).

The older tributaries of the Gautami remained as the Gaderu and the Coringa channels which are about 21 kilometres and 11 kilometres long, respectively. These are the most prominent canals through which fresh water is drained into the Kakinada Bay from the Gautami‐Godavari during the south‐west monsoon period (Figure 2). The deltaic wetlands of the Gautami‐Godavari Estuarine system have many channels and creeks criss‐crossing through the mudflats.

Over a period of many years, these mudflats had developed vegetation exhibiting an ability for salt‐water tolerance (Figure 3). As the Kakinada Bay started becoming shallower, it promoted further growth of mangroves. Mangroves also exist in the Godavari River mouth near Bhairavapalem and the Coringa area. Based on the functional classification they may be described as a mixture of Riverine (Gaderu, Coringa), Fringe (towards the Bay of Bengal and south‐western bay) and Basin (towards the land side) types. Probably, this is the only place in India where three species of Avicennia, i.e. Avicennia officinalis, Avicennia marina, and Avicennia alba are found together in mixed forests. It is a very dynamic system with diverse habitats ranging from fresh water to brackish and marine. Mangrove forests situated in these deltaic wetlands cover an area of 33,150 hectares. The species structure, landscape and hydrology keep with time and human activities. There is also significant loss in mangrove area (Malini and Rao, 2004) but reforestation efforts seem to be compensating this loss (Ramasubramanian et al., 2006). The main human impacts are from fishing, shrimp culture and oil exploration. The scenario might be different elsewhere with agricultural expansion (81 per cent), aquaculture (12 per cent) and urban development (2 per cent) being identified as the major causes of mangrove deforestation (Giri et al., 2007).

The area near Kakinada, especially the Gaderu, Matlapalem village and the Coringa, is rich in fisheries as evidenced by intensive fishing practiced by local villagers. Another main local economic activity is shellfish harvesting for lime production. This activity is closely associated with the presence of a huge biomass of bivalves and gastropods in the intertidal mudflats along the west and south‐west borders of the Kakinada Bay facing the mangroves. Mangroves act as breeding, spawning and nursery grounds for coastal and offshore fish and shellfish. The mangrove wood is used for construction purposes and mangrove habitat was cleared for agriculture, aquaculture and salt production. In the mangrove communities, penaeid shrimps were the most important commercial catch by value (53 per cent), followed by 32 per cent fish, 15 per cent crabs and 1 per cent shrimp seed (Dahdouh‐Guebas et al., 2006). The importance of mangroves to fisheries and shellfish can be explained as mangrove area is nursery grounds for juvenile prawns and fishes.

Mangrove leaves decay on the floor and form nutrient‐rich organic detritus that forms the food for many aquatic organisms thriving in this ecosystem. The detritus, as particulate matter, enters into the food chain and is exported offshore as seen by tracing stable carbon and nitrogen isotope studies (Dehairs et al., 2000). The mudflats are habitat for crabs such as mud crabs (Scylla spp., Figure 4). Because of their nutritive value and good export market, crab culture is becoming widely popular in this area. Initially, crabs were in demand after shrimp and lobster in the food market. But, due to growing popularity in the international market, these are currently in the second place after shrimps. The Gautami‐Godavari Estuary dominates all other estuarine mangrove areas on the east coast in the crab resources.

Mangrove leaves especially of A. spp. are eaten by feral water buffaloes which are prevalent in this area (Figure 5).

Bhairavapalem, near Gautami‐Godavari river mouth, is an exclusively fishers' village and a number of fishing boats (mechanised and manual) operate from here. Starting with the onset of the south‐west monsoon, full‐scale operation of collecting prawn seed (mostly Penaeus indicus and P. monodon) begins involving most of the fishermen in this region. Sometimes, whole family staying on a boat is a common sight (Figure 6).

Apart from ecological benefits as mentioned earlier, mangroves act as protective physical barriers to cyclonic storms, tidal water incursions and even tsunamis. However, the magnitude of protection depends on the structure and density of the vegetation. O'Hare (2001) demonstrated that “top down” institutional measures to reduce the effects of storm damage such as those introduced in the aftermath of tropical cyclone 07B in the Godavari Delta area, including early storm warning and evacuation procedures and rehabilitation programmes, remain largely ineffective. It is suggested that introduction of more “bottom up” community‐based programmes which seek to improve the risk awareness and risk‐avoiding abilities of affected individuals and groups would be much more beneficial. In recent years, due to intensive shrimp‐culturing practices, large‐scale destruction has been caused to the mangrove vegetation (Figures 7 and 8). Increasing pressure on the mangrove forests with intensive prawn culture initially highlighted the threat to this ecosystem as observed also in other tropical countries. But, intervention from the Indian Government by declaring ecologically sensitive coastal areas, between low and high tide levels, including mangroves, as Coastal Regulatory Zone (CRZ) in 1991 has imposed restrictions on the developmental activities.

Andhra Pradesh Coastal Zone Management Authority is the government body responsible for protecting and improving the environmental quality of the area through integrated coastal zone management plans. Once these plans are reviewed by the state authority, they are forwarded for approval to the National Coastal Zone Management Authority. But the CRZ has been amended several times and in 2008 the government superseding the earlier CRZ has come up with a Draft Coastal Management Zone (CMZ) notification. Although mangroves have been included in Zone 1 under CMZ, there has been widespread concern from coastal fishing communities about denying them access to the ocean and housing sites. It will be helpful to enact a legislation along the lines of the Scheduled Tribes and other Traditional Forest Dwellers (Recognition of Forest Rights) Act, 2006, to safeguard the interests and rights of the fishing communities (Swaminathan, 2008).

India had experienced a warming trend of 0.6°C per century with the southern Indian State of Andhra Pradesh recording a highest temperature of 49°C in May 2002 (National Oceanic and Atmospheric Administration, 2002). Andhra Pradesh is home to the magnificent Godavari (as described earlier) and Krishna mangroves. With an evident increase in average temperature and threat of global warming this ecosystem is vulnerable to climate change. The mangrove ecosystem of the east coast of India has been identified as one of the most vulnerable regional habitats to be exposed to sea‐level rise (Alongi, 2007). Increasing salinity and precipitation patterns also affect distribution of salt‐tolerant mangroves such as A. spp. and Rhizophora spp. The seedlings of all species require very low salinity for their growth; hence, a rise in salinity could affect their survival, growth and productivity (Jagtap and Nagle, 2007). Rising sea‐level brings in salts and sulphates; diminution of rainfall reduces mudflow and nutrient influxes. Increased frequency of tropical cyclones with inundation of low‐lying areas and salt‐water incursion is also not ruled out. Increasing temperature could also cause decreased tree height and leaf size in mangroves (Singh, 2002). These changes might ultimately result in changed biodiversity and species migration towards land. There are two major problems putting up pressure on mangroves. One is sea‐level rise due to climate change and the other is growing human population in the coastal areas. The former exerts pressure from the seaward side while the latter from the landward side. Forests are likely to be squeezed as an ecosystem between these two. The costal population will be increasingly restricted by economic pressures and public policies that respond to the issues of global change and population explosion. Ultimately, if the situation is allowed to be continued, both mangroves and their dependent human population will stand to lose. The local fishermen belong to one of the poorest communities in India with an average income of 3,500 Indian rupees (INR) per annum. With dwindling mangroves and associated fisheries, they feel that their livelihood is threatened and their survival endangered. Hence, resource management and land‐use planning are to be effectively anticipated and implemented with active participation of local communities.

Changes to the El Niño effect may lead to increased diseases such as malaria in, for example, India. Australia and New Zealand are at risk of increases in the existing arbovirus diseases (Dale and Knight, 2008). Mosquitoes of 12 species belonging to five subgenera and nine genera were recorded in the Coringa mangrove forest in the study area (Rajavel et al., 2006). It was further reported that the maximum number of species (ten) occurred in larval habitats during low‐salinity season (October) compared with only two species in high‐salinity season (March). This suggests that these vectors might migrate landwards with a rise in salinity. This could eventually lead to proliferation of mosquito‐related diseases in nearby habitations.

There are several environmental, social and economic benefits arising from restoration initiated by reforestation. The changing landscape due to restoration could stop erosion and salt water incursion up to some extent. It could also increase fish catches as more mangrove area would be available to fishes as they are attracted to mangroves for protection and food. As mentioned earlier, mangrove leaves are rich source of organic carbon for many organisms that live in this habitat. Feral buffaloes graze on mangrove leaves and are milked by local people. The other benefits of reforestation activity are generation of daily‐wage employment through contract labour and nursery maintenance. It is reported by various sources that the area of accreted and restored mangroves in India is almost equal to the area of degradation, land use conversion and erosion. Hence, it comes as no surprise when a recent remote sensing study reports a marginal increase in mangrove forest cover area in India (Giri et al., 2007).

The restoration of mangroves in the Godavari area was initiated by canal digging during the period from 1999 to 2004. There are mainly two agencies involved in this process. One of these is the Forest Department of the Government of Andhra Pradesh and the other is the M.S. Swaminathan Research Foundation, an NGO. These agencies are being assisted by local bodies consisting of villagers and fisherfolk. The starting phase was the participatory rural appraisal, consisting of transect walks, resource mapping and analysis of succession in mangrove communities. Information on hydrology and geomorphology was collected and micro‐plans for restoration were prepared for each village identified near the degraded area. A mangrove management unit was identified for each village which included both degraded mangrove habitat and existing vegetation. Two types of village level institutions (VLI) were constituted, namely, Eco‐Development Committee (EDC) and Vana Samrakshana Samiti (VSS) (literally, Forest Preservation Society). Members of these two VLIs were being trained in nursery maintenance and fieldwork. The soil salinity of the degraded area is normally about 140 parts per thousand (ppt) during summer, and for reducing this high‐salinity tidal flushing was facilitated by constructing canals. The restoration practice involved digging of main canals at an angle of 45° to the natural creeks and side canals at 30° to the main canals. A fish‐bone design of canals was introduced which seemed to be more efficient in tidal flushing than the rectangular pattern. The predominant endemic mangrove species of this area were chosen for plantation. These species are A. marina, A. officinalis and Excoecaria agallocha. A few other species such as Aegiceras corniculatum, Bruguiera spp., Rhizophora spp. and Xylocarpus spp. were also occasionally planted. The plantings were mostly carried out during October and November just after the retreat of the south‐west monsoon when the salinity of the creek water is in the range of 10‐15 ppt. The eight‐month‐old saplings from the nursery were used for planting along the slopes of the canals with a spacing of 2 metres. Nurseries were well established (Figure 9) and about 55,000 mangrove saplings were planted till October 2006. The members of VLIs were employed as daily‐wage labourers in this work. Detailed information and data about mangrove reforestation are provided in Table I.

The positive result of reforestation since the past few years is seen as an increase in mangrove area.

The key stakeholder in this activity is the fishermen community. The mangrove‐dependent fishermen were involved in raising mangrove saplings and in the selection of degraded mangrove areas, canal alignment, digging and planting (Ravishankar and Ramasubramanian, 2004). Since then, fish catches have been greater than before and biodiversity of the area has enhanced as indicated by an increase in crab, otter and avian populations. Looking at the economic aspects of the operation the average cost of restoring one hectare of degraded area is estimated to be in the range of 20,000‐30,000 INR. According to existing published information the net gain from restoring one hectare of fully established mangrove forest is estimated to be US$2,226 (see Appendix).

Climate change disrupts the livelihood of mangrove‐dependent communities. The effects may not be visible immediately but take a long time to manifest. The mangrove ecosystem is naturally adapted to cope with fluctuations in sea‐level as glacial and interglacial periods alternated over the last two million years. With a rising sea‐level survival of mangrove forest depends on its ability to accrete soil or to migrate inland. Currently, soil accretion rates in mangrove forests are keeping pace with mean sea‐level rise (Alongi, 2007). In the Godavari Delta, the survival of the mangrove forest is endangered by a lack of sufficient sedimentation due to the construction of dams (Malini and Rao, 2004).

The reforestation effort, at a local level, described in the study is an initial step towards adaptation aimed at coping with ongoing rapid sea‐level rise. Implemented successfully, this kind of participatory activities eventually leads to mitigation and disaster preparedness. If reforestation can take place with the added benefit of employment to the local villagers, it is the best option. But restoration activities that use local people as contract labour only and not involving them in the long‐run management of the restored ecosystem may not be successful (Rönnbäck et al., 2007).

Apart from being prepared for facing the consequences of sea‐level rise the long‐term benefits of establishing the original mangrove communities are enormous for the local people and the coming generations. The question whether changing the landscape by reforestation will address the issue of climate change or not will only be answered after a long‐term monitoring.

The increase in mangrove biomass is not only beneficial for mitigating sea‐level rise but also for enhancing carbon sequestration. It was also suggested by Chmura et al. (2003) that mangrove forests sequester carbon faster than terrestrial forests. Moreover, the role of mangroves as carbon sinks may be ecologically important since decomposition in mangrove soils occurs mainly through sulphate reduction, which would contribute less to greenhouse gases. This is an extra advantage of increasing mangrove biomass. Apart from mitigating the ill effects of climate change, there are several other benefits accruing from restoration activity. Environmental advantages of restoration are protection from storms, tsunamis and erosion and increase in green cover. The direct returns are increased fish catches, preservation of breeding grounds and nurseries and conservation of commercially important species. Restoration activity also brings in social paybacks such as employment to the local villagers and prevents mass migration towards already overpopulated urban agglomerations in the neighbourhood. In the context of the above discussion, it could be concluded that changing the landscape by planting more trees will definitely aid in restoring the original habitat with multiple long‐term returns to the local people. Restoration could eventually lead to the preservation of biodiversity of the area and sustainable development of the human communities that are dependent on these resources for their livelihood. As a follow‐up of this successful reforestation programme, it is recommended that:

• Other degraded areas in the Godavari Delta region may be identified for starting similar activity with the formation of more EDCs and involving more NGOs.

• Research on the biology of propagation and restoration of mangrove species to decrease the mortality rate of the planted young saplings may be initiated.

• Carbon sequestration process in restored mangroves may be studied in detail and potential carbon credit benefits to the stakeholders, if any, highlighted.

• Spreading of awareness for climate change to local children through school education may be initiated. Schools may also organise awareness camps in the restoration areas so that children can participate in field activities and understand the significance of the project.

• Results from this project may be disseminated to a wider audience and target groups in those areas where mangrove ecosystems and livelihoods of the local people are threatened.

• Information generated by ethnobiological research may also be used to strengthen the management of ecosystems.

The author thanks anonymous reviewers for their comments on the earlier version of this paper.

• Total area restored in hectares=375.

• Total cost of restoration in INR at three different restored sites (200, 10 and 165 hectares as reported in Table I): Equation 1 

• For fully established community of 375 hectares, the estimated value of goods and services: Equation 2 

• Estimated net gain (3‐2)=US$834,750=834,750/375=2,226/hectares.

Notes:^aData from Table I was used for estimating the cost of restoration; ^bFor 165 hectares, an average cost of restoration (based on reported high and low costs) was used for estimation; ^cRefer to Anon. (2002). For converting INR to US$, an exchange rate of US$1=50 INR was used (January 2009).

Raghavendra G. Rao received his MS and PhD from Vrije Universiteit Brussel, Belgium in Human Ecology. He was a recipient of the European Unions Doctoral fellowship and initiated research in international scientific cooperation project of European Union (EU) between Belgium and India. Prior to that, he has also worked in a science and technology for developing countries program of EU between Belgium and Kenya. His teaching and research interests are wide and multidisciplinary in nature mostly focusing on environmental management, environmental policy, sustainable development and business ethics. Currently, he is associated with the Centre for Environmental Management at Institute of Management Technology, Ghaziabad, India. Raghavendra G. Rao can be contacted at: rgrao@imt.edu