Introduction  

Tropical forests, which harbour most of the world's plant diversity, continue to be destroyed at unprecedented rates (Myers et al., 2000; Pittman & Jorgenson 2002). The faunal species associated with these forests are also affected by one or another reason. The wet evergreen forests of the Western Ghats of India are one of the global biodiversity hotspots, being rich in biodiversity and endemic species (Myers et al ., 2000), it is also under the threat of deforestation. It harbours some of the relic elements in the remnant forests, which are in patchy distribution. Myristica swamps are one such threatened ecosystems occuring in these remnant forests of Western Ghats . They are undoubtedly priceless assets for the evolutionary biologist, since many features of Myristicaceae are primitive in origin and hence regarded as ‘living fossils'.

What are Myristica swamps?

Swamps are wetlands dominated by woody plants. They have fairly deep water and minimal growth of emergent plants. A marsh, though sometimes used synonymously with swamp is more applicable to a large area of wetland where the dominant vegetation consists of low-lying grasses, rushes and sedges. Swamps have a high water table and occur near rivers, streams, and lakes. The soils are saturated (or soaked) with water. The soil is thick, black, and nutrient-rich providing an environment for water tolerant trees and other organisms. Freshwater swamps occur in many parts of the world,

Valleys of Mississippi and its tributaries, in Sweden , Odzala National Park, Congo , in the Malaysian region, Papua New Guinea , Swamp forests fringe the Amazon and its tributaries, etc. In India , freshwater swamps are reported from the Siwalik and Doon Valley and the Brahmaputra Valley (Rao, 1994).

Myristica swamp is any freshwater swamp where any one or both of the exclusive swamp growing trees of the family Myristicaceae namely Gymnacranthera canaria or Myristica fatua var. magnifica are present. These swamp species may occur in association with some other, usually evergreen trees having varied degrees of flood tolerance.

  Distribution of Myristica swamps

Davis et al. (1934), in their working plan for North Mangalore Forest Division Madras reported about “swampy evergreens” with Myristica spp. confined to low lying poorly drained areas, without specifying the exact locations. However, KrIishnamoorthy (1960) reported Myristica swamps, for the first time, as a special type of habitat from Travancore. These swamps were found in the valleys of Shendurney, Kulathupuzha and Anchal forest ranges in the southern Western Ghats . Champion and Seth (1968) classified such swamps under a newly introduced category ‘ Myristica Swamp Forests' under the Sub Group 4C. Talbot (1911), in The Forest Flora of the Bombay Presidency and Sind vol. II, reported just one locality, near Malemane, in Siddapur of Uttara Kannda for Myristica magnifica . The northernmost swamp known is associated with a sacred grove in the Satari taluk of Goa (Santhakumaran et al. 1995). However, they have not reported M. fatua or G. canarica from the Goa locality. The photographs in their paper, however, are indicative of the presence of G. canarica , thereby meriting the classification of the habitat as a Myristica swamp .

Varghese and Kumar (1997) differentiate between two types of swamps having Myristicaceae, in the Travancore region: 1. Myristica swamp forest, restricted to below 300 m, fringing sluggish streams. 2. Tropical sub-montane hill valley swamp forest- found as narrow strips of water-logged areas. Whereas the former has M. fatua as well as G. canarica , in the latter, G. canarica is found along with Mastixia arborea and several others. Such bifurcation of these swamps does not have enough justification. The Atlas of Endemics of the Western Ghats ( India ) by Ramesh and Pascal (1997) shows that G. canarica and M. fatua occur from sea level to 700 m and 1000 m altitudes respectively.

More detailed studies on the Myristica swamps of Uttara Kannada in Central Western Ghats have been made recently. These swamps are isolated and situated in localities from near sea level to about 450 m altitude (Chandran et al . , 1999; Chandran and Mesta, 2001).

 Figure 1. Myristica swamps distribution in Western Ghats  

Study area  

The Uttara Kannada district, formerly North Kanara (13°52" to 15°30"N and 74°05" to 75°5"E), is located towards the centre of the Western Ghats. The district with 10,250 km² of area is one of the most forested in South India with about 70% of the land under forest cover, including forest plantations. Here the Western Ghats seldom exceeds 700 m in altitude. The district is a maze of steep hills with narrow valleys. Tropical evergreen to semi-evergreen forests form the natural climax vegetation in most parts of the district, which receive 200 to 500cm of rainfall. The survey has been carried out in five localities of Honnavar and Siddapur taluk (Figure 2).

Figure 2. Surveyed localities

Materials and Methods

The sampling has been carried out in five Myristica swamp localities namely, Kathalekan, Malemane, Torme, Halsolli and Mundigethagu. The survey was a random opportunistic survey visiting all the swamps and listing all the information regarding flora and fauna. For amphibians, time constrained samplings were carried out (2x2 man hours) from 17:30 to 19:30 hrs in five localities. During the survey, amphibians were searched using torchlight and also their vocal calls. Microhabitats like litter, wood logs, waterbodies, rocks, bushes, etc., were thoroughly searched. Keys of Daniel (1963a and b , 1975 ); Daniel and Sekhar (1989) and Daniels (1997a , b and c ) were used for species identification.

Photographs and geographical co-ordinates of occurrence using Global positioning system (GPS) were noted. Specimens were identified with the help of regional and other floras for plants and faunal elements are identified with the help of literature and experts.

Results and Discussion

Flora

The survey resulted in 64 trees, 24 species of shrubs and herbs (which include 8 species pteridophytes) (see Annexure I&II). As per the Myristica swamp definition it should have one or both exclusive swamp species viz., Gymnacranthera canaria or Myristica fatua var. magnifica, all five swamps have these trees as prominent tree species. Apart from these species Myristica swamps also associated with some of the flood tolerant evergreens like, Mastixia arborea , Calophyllum apetalum, Dipterocarpus indicus, Elaeocarpus tuberculatus, and Lophopetalum wightianum . Recently one new species was described from the Myristica swamps of Uttara Kannada viz., Semecarpus kathalekanensis (Swaminath, 2000). Three surveyed swamps have this species in an isolated patch of few trees. The swamp has high level of Western Ghats endemism among trees; 34 species are endemics.

Notable of the ground layer are rare shrubs and herbs like Apama siliquosa , Ochlandra scriptoria , Calamus spp., Arenga wightii , Pandanus spp., Nothopodytes foetida , Alpinia malaccensis , Jerdonia indica , Neurocalyx calycinus Begonia maabarica and Schumanniatus virgatus . An aroid Lagenandra ovata and Elatostemma lineolatum and Pellionia heyneana , both members of Urticaceae, are found abundantly in all the surveyed swamps. Pinanga dicksonii , a slender endemic palm of the Western Ghats , grows gregariously in all the swamps. In case of ground layer 7 species are endemic to Western Ghats . The notable of the Pteridophytes are Angiopteris evecta , Bolbitis appendiculata , Cyathea nilgiriensis , Osmunda regalis , Pronephrium triphyllum , Selaginella , Pteris , Staenochlaena palustris and Tectaria wigthii .

Fauna

These swamps also harbour many endemic and endangered fauna of the Western Ghats . The survey resulted in 15 species of mammals, 59 species of birds, 22 species of reptiles (including snakes), 29 species of amphibians, 16 species of fishes, 109 species of butterflies and six species of damselflies.

About six species of damselflies of are found in these swamps (see Annexure III) including Phylloneura westermanni , which is a range extension from Coorg and Wayanad. Other species are, Clear-winged Forest glory ( Vestalis gracilis ), Malabar torrent dart ( Euphea fraseri ), Stream ruby ( Rhinocypha bisignata), Black-tipped forest glory ( Vestalis apicalis ) and Pied reed tail ( Protosticta gravelyi ). Most of the species are found along the perennial stream inside the swamp. Clear-winged Forest glory ( Vestalis gracilis ), is found in the undergrowth of interior forest areas.

About 109 species of butterflies representing five families (see Annexure IV) are found in the Myristica swamps. Family Nymphalidae is dominated by 43 species followed by Papilionidae 16 species, Pieridae 13, Lycaenidae 18 and Hesperiidae 19 species. Many species are found basking in the open canopy areas. Malabar tree nymph ( Idea malabarica ), an endemic species found in moist, shady areas and in two swamps they form congregations. Evening browns and Bush browns of family nymphalidea are found in the thick litter covered areas and in the vicinity of Ochlandra scriptoria , Calamus spp. The members of the family Hesperiidae are found in the swamp edges, grasslands and open canopy areas.

16 species of fishes are found in the perennial streams of these swamps (see Annexure V). Most of them are generalists species found in the Western Ghats . Garra gotyla stenorhynchus , Rasbora daniconius , Danio aequipinnatus are prominent species.

About 29 species of amphibians are listed from the five Myristica swamps (see Annexure VI). Order Anura comprises eight families and Gymnophiona the family Ichtyophiidae. The family Dicroglossidae and Rhacophoridae comprises seven species each. Whereas the family Nyctibatrachidae and Ranidae comprises three species each. Some of the notable species are Micrixalus saxicola Nyctibatrachus major , N . petraeus Philautus ponmudi, P . neelanethrus , Polypedatus pseudocruciger and Rhacophorus malabaricus .

21 species of reptiles include 13 species of snakes found in the surveyed swamps (see Annexure VII). The notable snakes are Python ( Python molurus ), King cobra ( Ophiophagus hannah ), Humpnosed pit viper ( Hypnale hypnale ), Malabar pit viper ( Trimersurus malabaricus ), Trinket snake ( Elaphe helena helena ), etc.

About 59 species of birds found in these swamps (see Annexure VIII). Some of the endemic species like, Wynaad laughing thrush ( Garrulax delesserti ), Great pied hornbill ( Buceros bicornis ), Bluewinged parakeet ( Psittacula columboides ) are found in all the five surveyed swamps. Indian great horned owl ( Bubo bubo L.,), is a common species found in the riparian vegetation of Kathalekan, Halsolli and Torme swamps. Other species like, Fairy bluebird ( Irena puella ), Malabar whistling Thrush ( Myiophonus horsfieldii ) and Wagtails are found along the perennial streams.

About 15 species of mammals found in these swamps (see Annexure IX), which include an endemic and endangered primate Lion tailed macaque ( Macaca silenus ). This species is associated with the relics of the primary forests in Siddapur having the Myristica swamps and Dipterocapus.

Conclusion

In Myristica swamp the perennial streams and its associated flora harbours many of the endemic and endangered fauna of the Western Ghats . The swamp and its immediate surrounding forests have a number of wild fruit bearing trees which include Garcinia, Myristica, Syzygium, Holigarna, members of Lauraceae, Meliaceae, Myrtaceae, etc. which provide food for many wild mammals and birds. Due to high watershed value and ecological value, it is necessary to conserve and document the biodiversity of these swamps in a proper way.

In the study area most swamps are presumably extinct due to human impacts of various kinds. The swamps are encroached for agricultural lands and areca plantations. The two of the studied swamps are at risk of disappearance due to areca plantations. The pressure is mounting on the last traces of the remaining swamps, due to mainly ignorance about the value and evolutionary significance of these ancient patches of forests. Rich biodiversity of swamps along with the evolutionarily significance demands the immediate policy measures to conserve these Myristica swamps— fragile ecosystems in remnant forest patches of Uttara Kannada. Special efforts should be made to locate more of these swamps lying hidden in the recesses of the Western Ghats .

Acknowledgements

We thank Mr. Divakar K. Mesta, Dr. K.V. Gururaja, Mr. Karthick B., Mr. Vishnu D Mukri, and Mr. Shrikanth Naik for their assistance in field work, identification and data collection.

Reference  

1. Pittman NC, Jorgenson PM (2002) Estimating the size of the world's threatened flora. Science , 298 , 989.
2. Champion, H.G. and Seth, S.K. (1968) A Revised Survey of the Forest Types of India ( New Delhi : Manager of Publications).
3. Varghese, A.V. and Kumar, B.M. (1997) Ecological observations in the fresh water swamp forests of southern Kerala , India . J. of Tropical Forest Science 9(3), 299-314.
4. Myers, N et al. (2000) Biodiversity hotspots for conservation Priorities. Nature 403, 853-858.
5. Chandran, M.D.S., & Mesta, D.K. On the conservation of the Myristica swamps of the Western Ghats . In Forest Genetic Resources: Status, Threats, and Conservation Strategies (eds Uma Shaanker, R., Ganeshaiah, K.N., & Bawa, K.S.) 1-19 (Oxford & IBH, New Delhi , 2001).
6. Chandran, M.D.S., Mesta, D.K. & Naik, M.B. Inventorying and Conservation of the Myristica Swamps of Uttara Kannada. Report (Forest Research and Training Institute, Bangalore, 1999).
7. Rao, R.R. Biodiversity in India (Floristic Aspects) (Bishen Singh Mahendra Pal Singh, Delhi, 1994).
8. Davis , P.W., Krishnaswami, M.H. and Wilson , C.C. (1934). Working Plan for the North Mangalore Forest Divison, Madras ( Madras : Supdt. Of Government Press)
9. Krishnamoorthy, K. Myristica Swamps in the evergreen forests of Travancore . In Tropcal Moist Evergreen Forest Symposium (Forest Research Institute, Dehradun, 1960).
10. Talbot, W.A. (1911). Forest Flora of the Bombay Presidency and Sind . Vol. 2 ( Poona : Government Photozicographic Press).
11. Ramesh, B.R. and Pascal, J.P. (1997). Atlas of endemics of the Western Ghats ( India ), Pondicherry : French Institute).
12. Santhakumaran, L.N., Singh, A. and Thomas, V.T. (1995). Description of a sacred grove in Goa ( India ), with notes on the unusual aerial roots produced by its vegetation. Wood. Oct – Dec., 24-28.
13. Daniel, J. C. 1963a. Field guide to the amphibians of Western India . Part I. Journal of the Bombay Natural History Society , 60(2): 415-438.
14. Daniel, J. C. 1963b. Field guide to the amphibians of Western India . Part II. Journal of the Bombay Natural History Society , 60(3): 690-702.
15. Daniel, J. C. 1975. Field guide to the amphibians of Western India . Part III. Journal of the Bombay Natural History Society , 72(2): 506-522.
16. Daniel, J. C., and Sekhar, A. G. 1989. Field guide to the amphibians of Western India . Part IV. Journal of the Bombay Natural History Society , 72(2): 194-202.
17. Daniels, R. J. R. 1997a. A field guide to the frogs & toads of the Western Ghats , India . Part I. Cobra , 27: 1-25.
18. Daniels, R. J. R.1997b. A field guide to the frogs & toads of the Western Ghats , India . Part II. Cobra , 28: 1-24.
19. Daniels, R. J. R. 1997c. A field guide to the frogs & toads of the Western Ghats , India . Part III. Cobra , 29: 1-13.

Annexure I. Checklist of Tree species found in the five Myristica swamps.  

  Annexure II. Checklist of Shrubs and Herbs (including pteridophytes) species found in the Five Myristica swamps.

Annexure III. Checklist of Damcelflies found in the Five Myristica swamps.

  Annexure IV. Checklist of Butterflies found in the Five Myristica swamps.

Annexure V. Checklist of Fishes found in the Five Myristica swamps.  

  Annexure VI. Checklist of amphibians found in the Five Myristica swamps.

Annexure VI. Checklist of amphibians found in the Five Myristica swamps.

Note: CR: Critically Endangered, EN: Endangered, VU: Vulnerable, DD: Data deficient, NT: Near Threatened, LC: Least concern

Annexure VII. Checklist of reptiles found in the Five Myristica swamps.  

  Annexure VIII. Checklist of birds found in the Five Myristica swamps.

  Annexure IX. Checklist of mammals found in the Five Myristica swamps.

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