ECOSYSTEM SERVICES FROM SACRED GROVES OF UTTAR KANNADA A CASE STUDY

Transcription

1 ECOSYSTEM SERVICES FROM SACRED GROVES OF UTTAR KANNADA A CASE STUDY Rajasri Ray, M.D.Subash Chandran and T.V.Ramachandra Centre for Ecological Sciences, Indian Institute of Science, Bangalore Correspondence : rajasri@ces.iisc.ernet.in, mds@ces.iisc.ernet.in, cestvr@ces.iisc.ernet.in 22 nd -24 th December 2010 Page 1

2 Abstract Sacred groves, the fragmented climax forest patches preserved in the name of gods, are spread throughout Uttar Kannada district in various ecosystems from coastal belt to hill top. They are representing evergreen, semi-evergreen, mangroves and swampy vegetation with rich assemblage of flora and fauna. Although groves are well explored by scholars for their biodiversity and socio-religious importance, their potential in ecosystem services are scantily studied. We have assessed here four sacred groves for their plant diversity, endemism, hydrology and carbon sequestration. Groves have higher plant diversity and endemism (Shannon diversity 3) in comparison to surrounding landscape. Carbon sequestration potential ranges from tc/ha, comparable to climax tropical evergreen forests. Although, all the studied groves are associated with water bodies their hydrological importance is dependent on location as well as management. Issues related to current disturbance and its impact over the ecosystem services have been discussed also. Introduction Sacred groves are traditionally protected forest fragments associated with livelihoods of rural communities. Although their importance in community life is usually felt through religious-cultural practices their utility in life-sustaining services cannot be overlooked as per the available literatures. Depending on its location and management status, sacred grove can provide all basic ecosystem services like, provisioning, regulating, supporting and cultural/amenities which have not been properly explored yet (Table 1). Studies on sacred grove system are mostly concentrated towards inventory and documentation, biodiversity assessment especially angiosperms, anthropological and socio-religious issues. However, current resurgence of interest in the system promotes a fair number of ecological studies which in a way help us to understand the ecological dynamics of the groves. Ecological studies on groves can be categorized into two parts, 1) where grove is treated as unit system irrespective of its surroundings and 2) grove as part of the landscape. In both type of studies few ecosystem services have also been explored as a part of ongoing ecosystem dynamics within the grove system. Examples can be drawn from the works based on NTFP and medicinal plants (Khumbongmayum et al. 2005; Ulman and Mokat 2008) (provisioning services), maintenance of angiosperm diversity (Jamir and Pandey 2003), preserving endemic members (Jamir and Pandey 2003), nutrient cycling (Khiewtam and Ramakrishnan 1993), soil microbial carbon (Arunachalam and Arunachalam 2000) (Supporting services) etc. However, diminishing size and lack of proper recognition affect expected ecosystem services from sacred groves especially regulatory and supporting ones. A smaller grove can support local biota, may provide goods like NTFP, medicinal plants, fuelwood, etc. but long lasting services eg. ground water recharge, 22 nd -24 th December 2010 Page 2

3 flood control, fire resistance require larger dimension and proper management of the grove system. Moreover, there is hardly any study in this direction to assess the potential of the sacred grove for ecosystem services and their importance in livelihood maintenance. Uttara Kannada is one of the forest dominated districts in the state of Karnataka. This district belongs to Central Western Ghats region thus, harbours diverse life forms i.e. plants, animals and microorganisms. Uttara Kannada ecosystems range from evergreen-semievergreen forests to moist deciduous, savanna and coastal mangroves. Although numerical evidence is not available, a good portion of the district biodiversity is conserved through sacred grove system from time immemorial (Chandran and Gadgil 1998). Sacred groves are scattered throughout different landscape representing varied ecosystems of the district under traditional resource conservation system. Despite being recognized by the traditional communities and cultures for its valuable contribution to livelihood, groves are often subjected to negligence (especially the smaller ones) in terms of ecosystem services which require urgent attention from conservationists as well as decision makers. Present study aims to assess the ecosystem service potential of sacred groves in Uttara Kannada district and their role in livelihood maintenance. Study area Uttara Kannada district is situated between N and E and is divided into 11 taluks. For present study four sacred groves (SG1, SG2, SG3 and SG4) have been selected from Honnavar and Siddapur taluk (Fig.1). All but one is present in agricultural landscape thus representing fragmented patches of vegetation with an area of 1-2 ha. The remaining grove is situated on the hill slope facing south-west direction with an area of ~56 ha. All these groves have high social and religious value to the local community therefore, their management is considerably better in comparison to other observed groves in the region. Methods We have selected one provisioning (Water conservation) and two supporting services (plant diversityendemism and Carbon sequestration) for assessment purpose. Water conservation- year long observation and ground water measurement have been done as per standard methods (Basu and Jaiswal 2001). Plant Diversity-endemism- Whole area survey and transect cum quadrat methods have been adopted for diversity assessment as per selected grove area. Diversity indices (Shannon-Weaver, Simpson s and Margalef s) and endemism were calculated according to standard methods (Simpson 1949; Margalef 1958; Shannon and Weaver 1963). 22 nd -24 th December 2010 Page 3

4 Carbon sequestration- Species level above ground biomass was calculated through basal area equations and an indirect estimation has been done for calculating below ground biomass (Murali et al. 2005; Ravindranath and Ostwald 2008). Above Ground Biomass (AGB) (t/ha) = (BA), r 2 = 0.53, BA = Basal area in m 2 /ha. Below Ground Biomass (t/ha) = 0.26 * AGB The resultant biomass was multiplied by 0.5 for estimating carbon storage. Result and Discussion Sacred groves of Uttara Kannada are diverse in their distribution, management and protection status. Most except few groves are currently under different threats which affect their ecological integrity also. We have selected four groves with respect to their geographical position and impact upon the local community. First three groves i.e. SG1, 2 and 3 are present in heterogenous landscape along with agricultural field, villages, plantation and barren land. The fourth grove (i.e. SG 4) which is present on hill slope is comparatively less disturbed and bigger in size. Water conservation study has shown grove s potential in many ways (Table2). While fragmented groves have water in their shallow depression areas the hill slope grove supports perennial streams. Although water logged areas in fragmented groves have no direct role in community livelihood it has importance in microclimate maintenance within the grove area which supports numerous life forms especially lower groups. One of these small groves (SG3) has pond associated with it which is a great support for local community during lean season. On the contrary hill slope grove has immense impact on downstream economy because of the perennial streams originated from there. A round the year ground water monitoring study shows availability of water throughout the year which facilitates cultivation of cash crops like areca nut, vanilla, piper and coconut in the downstream village hamlet. Plant diversity analysis shows that groves harbor good diversity as Shannon index is always 3 and Simpson s value is also 0.9. Similarly species richness, basal area, tree density all is comparable to tropical forest values. A good number of endemic members are also noted from these groves as the percent endemism ranges from 23-57%. Carbon sequestration study shows that groves have future potential in this regard if they were maintained/protected with utmost care. Carbon sequestration capacity ranges from tC/ha. All four groves have shown dominance of young members (64-71%) indicating their ongoing growth thus store good amount of carbon as primary photosynthetic product. However, there are few older trees distributed in all four groves indicating past carbon storage which can be kept as long as possible. This preliminary study has shown that groves have varied response to ecosystem services. Hill slope grove (SG4) has shown better potential in comparison to the ones present in agricultural landscape (SG 1, 2 and 22 nd -24 th December 2010 Page 4

5 3) of Siddapur taluk. Perhaps small size and distance from the forest are the major limiting factors for the three groves in Siddapur. It is their reduced size and isolation in the agricultural field which affects plant diversity as well as endemism. Although diversity indices of the groves are comparable with other areas, but, presence of exotic/invasive and heliophytic members affecting their quality. Similarly, dominance of younger members and generalist species indicates past disturbances in the grove area. On the contrary SG 4, the hill slope grove, has been found in comparatively better condition as the entire slope is considered as sacred by the local people thus, disturbances are minimum there. Considering water conservation potential, groves in Siddapur taluk have shown diverse options. They have water logged areas and associated ponds which support life forms in many ways. Water logged areas have no direct use for local community but it helps to keep the temperature down inside the grove, thus supports small organisms and microbial communities. Grove associated pond is a good support for domestic water usage by local people and aquatic life forms. Coming to the hill slope grove, perennial streams have originated from there which support livelihood in downstream area in many ways. The water, which is available throughout the year, has been used for domestic as well as agricultural purpose. The predominance of cash crops like areca nut, vanilla, piper and coconut in the downstream area reflects the round the year water availability in the area. Threats to the ecosystem services Groves are nowadays under various threats ranging from natural to anthropogenic. Some major threats which have been observed during the study are mentioned below. Encroahment over the grove area this is one of the most common problems observed in most of the groves. Both local as well as government machinery are involved in this matter. Extension of coconut, banana and areca nut cultivation by the local people or state funded Acacia plantation are common scenario in the grove area. The loss of native plant members may affect the microclimate in the grove area which put grove biota in great risk of extinction. Similarly, as the native members have definite role in water conservation, changing pattern of vegetation may have an impact over the water availability in the downstream area. Collection of leaf litter and twigs- There is restriction over biomass collection from grove area. However, it has been seen that, fallen twigs, leaves etc. are usually collected by local people for manuring purpose. This uncontrolled collection of floor materials could be lead to the soil erosion, nutrient and moisture loss which ultimately affect ecological integrity of the grove. Developmental activities- Activities like temple or well construction, land quarrying etc. have major impacts over the grove system. These usually lead to frequent visitors in the area which affect the grove 22 nd -24 th December 2010 Page 5

6 system through damaging vegetation (mostly peripheral), disturbing ecological functions, introduction of exotic/invasive species etc. To mitigate these problems community level awareness generation is necessary. Several other measures like maintenance of native vegetation, minimize disturbance in the grove area, controlled collection of fallen materials, scientifically sound developmental planning can be taken for consideration. Conclusion Groves are lifeline for the rural community in many ways either socio-religious, cultural or livelihood maintenance. Although studies have pointed out their role in biodiversity conservation and ecological functions, very few of them have shown the linkage between biodiversity/ecology and rural livelihood. This study tried to assess the ecosystem service potential of the groves with an aim to strengthen the ongoing conservation efforts taken by government, NGOs and rural communities. The assessment would be helpful for decision makers also to prioritise the groves for conservation purpose based on their ecosystem services. References Arunachalam A and Arunachalam K (2000) Influence of gap size and soil properties on microbial biomass in a subtropical humid forest of north-east India. Plant and soil 223: Basu K and Jaiswal D (2001) Participatory impact monitoring study in representative watershed Makara (Uttar Pradesh). Technical Paper No. IGBP/WSM/128/2001 Chandran MDS and Gadgil M (1998) Sacred groves and Sacred trees of Uttara Kannada. In: Saraswati B (ed) Lifestyle and Ecology, Indira Gandhi National Centre for Arts, New Delhi. Jamir SA and Pandey HN (2003) Vascular plant diversity in the sacred groves of Jaintia Hills in northeast India. Biodiv and Conserv 12: Khiewtam RS and Ramakrishnan PS. (1993) Litter and fine root dynamics of a relict sacred grove forest at Cherrapunji in north-eastern India. For Ecol and Manag 60: Khumbongmayum AD, Khan ML and Tripathi RS (2005) Ethnomedicinal plants in the sacred groves of Manipur. Indian J of Trad Knowl 4: Margalef, DR. (1958). Information theory in Ecology. Gen. Syst. 3: Murali, KS., Bhat DM and Ravindranath NH (2005). Biomass estimation equations for tropical deciduous and evergreen forests. Agricultural Resources Governance and Ecology 4: Ravindranath, NH. and Ostwald M. (2008). Estimation of carbon stocks and changes and data sources. In: Carbon Inventory Methods: Handbook for greenhouse gas inventory, carbon mitigation and roundwood production projects. pp Springer. 22 nd -24 th December 2010 Page 6

7 Shannon, CE. and Weaver W. (1963). The Mathematical Theory of Communication, University of Illinios Press, Urbana, USA. Simpson EH. (1949). Measurement of diversity. Nature, 163: 688. Ulman YN and Mokat DN (2008) Sacred groves as a potential minor forest products reserve. International J of For Usufract Manag 9: Table 1. Expected ecosystem services from sacred groves Provisioning services Water conservation Freshwater supply Soil fertility NTFP (Medicinal plants, fruits etc.) Fuel wood (occasional) Supporting services IN ADDITION TO SOIL FORMATION, NUTRIENT CYCLING AND PRIMARY PRODUCTION Favourable microclimate for flora and fauna Carbon sequestration Pollination and seed dispersal Regulating services Regulation of hydrological flows (runoff control, soil water infiltration, groundwater recharge) Mitigation of natural hazard (Flood prevention, landslide reduction, soil erosion control, fire resistance) Cultural and amenity services Religious and cultural tradition Ethnic identity Landscape aesthetics Research and education 22 nd -24 th December 2010 Page 7

8 Table 2. Water conservation potential of the studied sacred groves Devaravatti Karikod Jattibana Karikan (SG1) (SG2) (SG3) (SG4) Nature of the Small water Small water Associated pond Perennial stream water body logged area logged area Availability (mo) Water utility Microclimate Microclimate Microclimate Microclimate maintenance maintenance maintenance maintenance Domestic use Domestic use Irrigation Fig 1. Study area details (Uttara Kannada district and grove locations) 22 nd -24 th December 2010 Page 8