Rajasri Ray Centre for Ecological Sciences Indian Institute of Science, Bangalore 560012 India team



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Developing strategies for conservation of threatened endemic biodiversity of the sacred groves of Central Western Ghats

Project report (2011)





Rajasri Ray

Centre for Ecological Sciences

Indian Institute of Science, Bangalore 560012

India


TEAM

Dr. Rajasri Ray (Principal investigator)


Mr. Vishnu Mukhri (Field assistant)

Mr. Mahabaleshwar Naik (Field assistant)


Dr. M.D. Subash Chandran (Advisor)

Dr. T.V. Ramachandra (Advisor)



CONTENTS


Acknowledgements

Summary

Introduction

Methods

Results

Discussion

Conclusion

References

Annexure

ACKNOWLEDGEMENT
We are grateful to Rufford Foundation, UK for the financial support to study on sacred groves of Central Western Ghats in Karnataka state, India. We thank Karnataka Forest Department for their support in this work. Thanks should go to Mr. Ananta Hegde Ashisar, Chairman, Western Ghats Task Force, Govt. of Karnataka for suggestions and active involvement in this program. We are also grateful to peoples of Siddapur for their help and co-operation during the field work. Finally, team members express their gratitude to all members of Energy and Wetland Research Group (EWRG) - Mr. G. R. Rao, Dr. Prakash Mesta, Mr. Vishnu Mukri and colleagues of Kumta field station for their help in project implementation and report preparation.

SUMMARY

Culturally protected forest patches or sacred groves have been the integral part of many traditional societies. This age old tradition which is on the decline today, indeed functioned as classical instances of community driven nature conservation sheltering native biodiversity, supplying NTFPs and supporting various ecosystem functions particularly hydrology.

The current work in Central Western Ghats of Karnataka, India, one of the richest regions for sacred groves, highlights that even small sacred groves here amidst humanised landscapes dominated by agriculture and plantations serve as tiny islands of biodiversity, especially of rare and endemic species. A study on population and regeneration status of four selected endemic tree species indicates that grove size and relative protection are key factors for survival of these endemics.

Among the various anthropogenic factors that contribute to the degradation of sacred grove system in the recent times, are weakening of traditional belief systems and associated laxity in grove protection. Revitalisation of traditional practices related to conservation of sacred groves can go a long way in strengthening natural ecological systems of fragile humid tropical highlands. The prevalence of some of the Critically Endangered tree species of the Western Ghats such as, Syzygium travancoricum and Vateria indica in some of the small groves studied, which are obviously the relics of the primary forests highlights that sacred groves can have a greater role especially in conservation of the threatened endemic biota if they are restored and managed well.



INTRODUCTION

Culturally protected forest fragments, popularly known as sacred groves are often relics of original forests that covered the region before forest cutting and burning with the spread of civilization. These preserved forest patches, which originally covered larger areas, are usually close to human settlement, especially in Indian highlands, were the abodes of gods, as their remains with often rare species and unique ecological functions still prove it. Shift in developmental paradigm and consequent changing socio-economic scenario, land use practices have transformed these patches leading into various stages of degradation. Groves’ supportive role in species maintenance, different ecological functions is well recognized.

Sacred groves present in humanized landscapes are especially important in this regard. They are often part of the heterogeneous landscape intermingled with agricultural field, plantation, barren land, water bodies as well as villages. Studies highlight that, groves support a good number of rare and endemic species, which are extra-sensitive compared to common species, and persist only in favourable niches, and the sacred groves are ideal places for them (Jamir and Pandey 2003; Jayarajan 2004; Sukumaran and Raj 2007). However, there are gaps in knowledge about these endemics, like their population status, reproductive biology, ecology, etc. necessitating the present study. In India, most studies on sacred groves have hovered around floral and faunal diversity and maintenance of rare threatened and endemic species with sketchy descriptions of the ecological profiles and disturbance regimes. Very few studies have adopted a landscape approach in this regard, considering grove as part of a landscape. Studies in Kodagu district of central Western Ghats, where the groves are relatively large sized and faith in their guardian gods still strong, groves harbour a good number of forest tree and bird species even outside the forest, in a landscape dominated by coffee, cardamom, black pepper and betel nut plantations on hill slopes and plains and rice fields in valleys, forming good connectivity of landscape elements. (Bhagwat et al. 2005; Page et al 2010). In Eastern Ghats highlands of southern peninsular India leaving forest areas aside, sacred groves continue to be the most species rich ecosystem in agricultural landscapes (Aiama 2007). However, no reports are available with focus on endemic species ecology and their survival in current disturbance regimes especially in the sacred groves in humanized landscapes.

Biodiversity conservation programs based on “Hotspot” declaration, protected area network etc. often harp on the presence of rare and endemic species, which act as indicators of conservation/threat status. This prioritization is mainly due to their limited distribution and spatio-temporal sensitivity which make them prone to population decline. The risk is greatly enhanced in humanized landscapes as these sensitive rare and endemic species are the earliest to vanish from drastically modified habitats, as compared to the commoner and more widespread species.

Forest patches/remnant forests/woodlands have often acted as shelter or refugia for rare endemic species in human modified landscapes. These patches although, vary in size, quality and distribution contribute significantly in maintenance of different life cycle phases of the species in an area. Studies have reported their role in pollination and seed dispersal by harbouring honey bees and small mammals, species diversity maintenance, avifauna survival and many others (Deb et al. 1997; Bodin et al. 2006; Page et al. 2010). Interestingly, in a good number of cases these patches are culturally protected forest segments associated with local communities. Sacred groves which are present in humanised landscapes have limitations in their spatial extent. In a highly productive landscape grove is represented either by cluster of trees or small, isolated patches of few acres of land facing various levels of disturbances. Despite their size limitations, these fragments conserve local biodiversity and offer important ecological services although studies are scanty to substantiate the latter (Ray and Ramachandra 2010). Except few ecological and floristic inventory studies, little is known about the ecological profile of these groves, adaptation of vegetation under adverse conditions and how do the diverse life forms survive in the system. Detailed study on these aspects would help us to formulate suitable conservation strategy along with the improvement in livelihood of local community.

Objectives of the study -

1) Inventorisation and spatial distribution of the sacred groves in the study area,

2) Mapping the distribution of endemic tree species in the sacred groves

3) To estimate population and regeneration status of few selected sensitive endemic species to understand sacred groves’ potential in sheltering such endemics.

4) To identify disturbance regime that caused the disappearance of sensitive endemic tree species from the landscape

STUDY AREA

Uttara Kannada is one of the well forested districts of central Western Ghats in the state of Karnataka, India. The Western Ghats along with Sri Lanka constitute one of the 34 global biodiversity hot spots (Myers et al. 2000). It harbours forests of varied kinds such as, tropical evergreen, semi-evergreen, moist and dry deciduous types. These forests in many places, because of human impacts through last few millennia have produced secondary kinds of vegetation such as savannah, scrub and grasslands (Pascal 1988). As is characteristic of most humid tropical mountainous regions of the world here too shifting cultivation, which involved slashing and burning of forest patches for raising crops for two-three seasons and shifting thereafter to newer patches with better soils, a practice through centuries, caused formation of secondary forests in vast tracts of low altitude Western Ghats. The slash and burn cultivators, who belonged to several indigenous communities, however, did not destroy all the forests. In almost every of their settlement they spared substantial patches of primary evergreen forests dedicated to the gods of villages. These forests in their original form ranged in size from few hectares to few hundred hectares in the central Western Ghats, as of Uttara Kannada and Shimoga districts, according to historical records. These are the sacred groves on the institution of which there has been a flourish of studies in the recent decades from many parts of India (Malhotra et al. 2001; Khan et al. 2008).

With Uttara Kannada district coming under British colonialism from the dawn of 19th century the local communities began losing their traditional hold over forest resources including the sacred groves. Throughout the 19th century the British brought various efforts at consolidation of their hold on forest resources. By the close of the century, bulk of the forests including sacred groves and shifting cultivation sites got merged with state reserved forests. What remained of sacred groves where local communities got still some hold are smaller ones that measure one to few hectares or merely fractions of a hectare that are dispersed amidst well populated undulating agricultural landscapes. Most of the larger groves of Uttara Kannada lost their special identities except for the fact that still there could be the deities in some parts of them where the local communities continue to worship (Chandran and Hughes 1997; Chandran et al. 2010).

Our study was concentrated upon 5 km X 5 km area (14.280 – 14.310 N latitude and 74.840 -74.900 E longitude) in eastern part of Siddapur taluk of Uttara Kannada district where landscape is undulating with cultivation in the low lands forming a mosaic with grassy plains, scrub, degraded secondary forests, monoculture tree plantations and small sacred groves elsewhere. Siddapur taluk itself represents a transition zone from the high rainfall (> 3000 mm/yr) rugged hills clad in evergreen forests towards the west to the relatively drier plains that merged with the Deccan Plateau to the east. Our study area is situated between the nearly unbroken forest belt of the Ghats proper to the west and the Deccan landscape towards the east. The tree plantations of the study area are mainly constituted of Acacia and Casurina. Rain fed rice is the major crop grown in the fields. During the dry season parts of the rice fields are used for growing vegetables, ginger, millets etc. Unlike in the more watered hilly terrain the betel nut gardens are less in number and area and are usually located some favourable spots with water sources, often situated in the vicinity of the sacred groves (Chandran and Gadgil 1998; Nagendra and Gadgil 1999; Nagendra 2001) (Fig 1).

Fig 1. Study area



Location of the sacred groves in study area



METHODS:

Area survey: Survey of India toposheet (48_J_15 , 1978), Google earth imagery, land use map prepared for the study area by Nagendra (1997) were used for gaining preliminary knowledge on the focal landscape.

Mapping and documentation of sacred groves: Sacred groves were identified based on earlier study done by Chandran and Gadgil (1998) and field survey with local community people. The geographic location and area of the sacred grove were demarcated using GPS (Garmin etrex vista) and the information was transferred to Map Info 7.5 version for preparing map and area estimation. Observations were made of the general geomorphological factors related to the groves and status of soil moisture conditions, litter cover, soil erosion etc. Details regarding the existing management regimes were recorded through interviews with the community elders.

Vegetation survey: As the groves were small (from ~17.8 sq. m to18, 000 sq.m) we recorded all the trees in all the groves in the study area.

Studies on endemic tree species: We inventoried the presence of endemic tree species of Western Ghats from all the sacred groves. In addition, we also noted down the presence of endemic tree species in other landscape elements such as secondary forests, human habitations etc. We chose four most sensitive endemic tree species viz. (Vateria indica, Syzygium travancoricum, Calophyllum apetalum and Diospyros assimillis) for assessing their population profile and regeneration status.

The GBH of these selected endemic tree species (≥ 30cm GBH) were measured wherever they occurred. The tree heights were also estimated and recorded in different height classes. For enumeration of saplings (> 1m in height but < 30 cm GBH) and seedlings (< 1 m in height) we laid 5m X 5m quadrants on the forest floor.



Study of Forest area outside the groves: A small forest patch was present in the south-west corner of the landscape. Using transect cum quadrant method we enumerated the trees and ground vegetation of this forest (transect length 180 m.; no. of tree quadrants 5 each measuring 10 m X 10 m with subplot for shrubs (5m X 5m) and herbs (1m X 1m))

Recording of disturbances: Details about weed infestation, invasion by species from nearby plantations, soil erosion, relative distance from roads, lack of protection, cattle grazing etc. have been collected.

Data analysis –



Sacred grove distribution – Distances between the groves and the only forest patch was calculated through Euclidean distance by using open source GIS software GRASS (http://ces.iisc.ernet.in/grass). The area-perimeter ratio of the groves was calculated through Map Info (Version 7.5).

Endemic species population and regeneration analysis – The population data collected on selected endemic species was categorised into GBH classes to understand the girth distribution of these species in different size classes from all the landscape elements.

The regeneration data (seedlings and saplings for each selected species) was collected from the groves and extrapolated for the entire groves.



Species richness and diversity - For forest tree species, richness (Margalef) and diversity (Shannon-Weiner, Simpson) indices were computed as per standard methodologies (Simpson 1949; Margalef 1958; Shannon and Weiner 1963).

Disturbance measurement- The severity of disturbance has been measured through scoring method with all disturbance parameters given equal weight. The value was expressed in terms of relative disturbance ((scored value/maximum disturbance value)* 100) (Devar 2008)

RESULT

S

Fig 2. Size class distribution of the sacred groves



Fig 3. Species-Area relationship in study area


acred grove area and endemism

A total of 53 groves have been recorded from the study area with area ranges from 17.98 sq. m to 18,220 sq. m. Size class arrangement of the groves has shown that ~60% of them have area <1000 sq.m. (Fig 2). Total area of the groves represents only 0.36% of the study area in comparison to 10.6% of the degraded natural forest. Rest of the area are occupied by agricultural field, areca nut gardens, Acacia plantation, small water bodies etc. The average distance of the groves from the forest patch within the study area is 2.83 km (± 1.17) and average area-perimeter ratio of the groves is 0.232 (Annexure I).

Sacred groves harbour 138 woody species among which 19 (13.7%) are endemic to Western Ghats region. Grove area and total species richness show typical species-area relationship in power form (Fig 3). 14 out of 19 endemics are exclusively confined to the sacred groves, the other five (Beilschmiedia bourdillonii, Holigarna arnottiana, Hydnocarpus pentandra, Terminalia paniculata and, Vateria indica) occur outside forest patch as well as in some other landscape elements (Table 1). Whereas, 18 of the endemics are evergreen trees Terminalia paniculata is deciduous in nature.

Forest Diversity and endemism

The non-grove forest patch (area 265 ha) in the study area shows moderate species diversity and richness (Shannon’s index 2.6, Simpson’s index (1-D) 0.89, Margalef’s index 5.52). Dominant species here are Aporusa lindlyana (IVI value 60.51), Terminalia tomentosa (IVI value 49.75) and Terminalia paniculata (IVI value 32.83). Beilschmiedia bourdillonii, Holigarna arnottiana and Terminalia paniculata are the only endemics present in the forest patch.

Table 1. Distribution of endemic tree species in different land use elements in study area

Genus (Family)

Sacred Grove

Forest area

Village garden / Common area

Actinodaphnae malabarica (Lauraceae)

Artocarpus hirsutus (Moraceae)

Beilschmiedia bourdillonii (Lauraceae)

Calophyllum apetalum (Clusiaceae)

Cinnamomum malabatrum (Lauraceae)

Diospyros assimilis (Ebenaceae)

Diospyros candolleana (Ebenaceae)

Drypetes confertiflora (Euphorbiaceae)

Flacourtia Montana (Flacourtiaceae)

Garcinia indica (Clusiaceae)

Holigarna arnottiana (Anacardiaceae)

Holigarna grahammi (Anacardiaceae)

Hydnocarpus pentandra (Lauraceae)

Ixora brachiata (Rubiaceae)

Knema attenuata (Myristicaceae)

Pittosporum dasycaulon (Pittosporaceae)

Syzygium travancoricum (Myrtaceae)

Terminalia paniculata (Combretaceae)

Vateria indica (Dipterocarpaceae)















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Population status and regeneration of the restricted endemics

We selected four endemic species for detailed study, because of their restricted distribution and association with shaded humid forests. These are Vateria indica, Syzygium travancoricum, Calophyllum apetalum and Diospyros assimillis, of which the first two are Critically Endangered (IUCN 2011). Vateria indica is found in eight (8) groves, of which Devaravatti bana of Mattigar and Gamadevaru bana of Kavachur accounted for major population of the species. Syzygium travancoricum is restricted in three (3) groves namely, Devaravatti bana (Mattigar), Kadkod Choudamma bana (Aralihonda) and Choudamma bana (Dugdimane). Similarly, Calophyllum apetalum has been found in two (2) groves Devaravatti bana (Mattigar) and Choudamma bana (Dugdimane) and Diospyros assimillis is restricted in three (3) groves Devaravatti bana (Mattigar), Kadkod Choudamma bana (Aralihonda) and Kereamma (Kalyanpur). GBH class distribution of the endemic members in the sacred grove shows typical “L” shaped curve indicating dominance of younger members. Height class also ranges from 10-25 mt. for these members (Fig 4).

Fig. 4. Population status of selected endemic tree species in sacred groves

Regeneration study on all four species has revealed marked differences among them. V. indica has highest seedling density on 10,458 ind/grove area followed by C. apetalum (9110



Table 2. Regeneration status of selected endemic trees in sacred groves of the study area

Species

Grove name

Village

Grove area (sq. m.)

Seedling density

Sapling density

Vateria indica

Bhutappana Bana

Dugdimane

46.5

5.58

2.75




Bhutappana Bana (3)

Aralihonda

774.2

61.9

10.29




Kattedevaru Bana

Arendur

824.2

65.936

16.484




Mastamma

Kavachur

845.5

8.52

33.82




Gamadeveru Bana

Kavachur

2274

79.59

579.87




Mariamman Bana

Hittalkoppa

4578

52.64

91.56




Kadkod Choudamma Bana

Aralihonda

10730

214.6

53.65




Devarabatti Bana

Mattigar

18220

10458.28

4227.04

Syzygium travancoricum



















Choudi Bana

Dugdimane

329.6

52.736

24.17




Kadkod Choudamma Bana

Aralihonda

10730

4549.52

1158.84




Devarabatti Bana

Mattigar

18220

8235.44

3498.24

Calophyllum apetalum



















Choudi Bana

Dugdimane

329.6

118.656

32.96




Devarabatti Bana

Mattigar

18220

9110

2405.04

Diospyros assimillis



















Kereamma

Kalyanpur

9264

222.336

370.56




Kadkod Choudamma Bana

Aralihonda

10730

107.3

321.9




Devarabatti Bana

Mattigar

18220

16.36

182.2

ind/grove area), S. travancoricum (8235 ind/ha) and D. assimillis (222 ind/grove area). On the other hand, sapling level is dominated by V. indica (4227 ind/grove area) with closely followed by S. travancoricum (3498 ind/grove area), C apetalum (2405 ind/grove area), and D. assimillis (370 ind/grove area) subsequently. Study of these members’ shows that Devaravatti Kanu in Mattigar village is the most important grove as it harbours all these four endemics with their growing stock. Choudamma Banas of Aralihonda and Dugdimane harbour three and two of these members respectively (Table 2).

Disturbances over the grove system –

We applied the impact of seven (7) disturbance factors on the groves. Based on the relative disturbance scores groves have been categorised into highly disturbed (76-100%), moderately disturbed (51-75%), less disturbed (26-50%) and least disturbed (0-25%).

Sixteen (16) of the groves belong to the highly disturbed category where relative disturbance score exceeds 76%. All the sixteen groves have very small area < 1000 sq. m; they are unprotected ones and are adjoining the roads. Lack of fencing makes them vulnerable to cattle grazing, trampling and human interferences.

Thirty five (35) groves are rank in moderately disturbed category (disturbance scores 51-75%). Notable disturbance factors are their smaller sizes and lack of fencing. Even, Devaravatti Bana of Mattigar which shelters all the four sensitive endemic tree species is moderately disturbed. This disturbance is due to the damages to the barbed wire fencing.

Two (2) groves that are less disturbed have their areas ranging from 2,000-10,000 sq. m. They have better degree of protection due to boundary demarcation and existing social norms. However, none of the groves comes under the least disturbed category.



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