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SECTION-2 Biodiversity
PAPER-4
MACROPHYTIC DIVERSITY IN CERTAIN WETLANDS OF BARAK VALLEY REGION IN ASSAM
Devashish Kar and Monjurul Hoque Barbhuiya


ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS AND DISCUSSION
REFERENCES


ABSTRACT: up | previous | next | last

Aquatic macrophyte (AM) diversity and its role in understanding the wetland ecosystem dynamics have tremendous significance. Species composition of the AM, their succession, and phytosociological status in four wetlands of the Barak valley, viz., Barak Nadi Salchapra Anua Beel, Satkarakandi Anua Beel, Ram Nagar Anua Beel and the Chatla Haor were studied during 1998-99. Twenty seven different species of AM were recorded from the studied wetlands which included five free floating, six rooted floating, three submerged and thirteen emergent species. Significantly, six AM species have been found to occur throughout the year. While Jussiaea repens showed flowering during April, Nymphaea nouchali bloomed during June-August followed by Nymphoides cristatum and N. indicum, which exhibited profuse flowering during September-October. Ipomoea aquatica depicted growth in population during July-August. Hydrilla verticillata, Vallisneria spiralis, Noechamandra alternifolia, Eleocharis acutangula, Sagittaria trifolia and Scirpus eriophorum were found to be dominant during the dry season. The floating varieties, viz., Eichhornia crassipes, Salvinia cucullata and Azolla pinnata were recorded throughout the year and were found to be associated with each other. Further, H. verticillata, V. spiralis and T. bispinosa were found to be associated. Phytosocial association has also been observed among Nymphaea sp and Nymphoides sp., as well as E. acutangula, S. eriophorum and Echinochloa stagnina. Species composition, seasonal distribution and succession along with phytosociology have been discussed in the paper.

INTRODUCTION: up | previous | next | last

The Barak valley region of Assam is blessed with a good number of floodplain wetlands harbouring a great variety of aquatic macrophytes. Information on phytosociological data for AM in any waterbody is of immense importance to understand the wetland ecosystem. Several works have been done on the phytosociology of different macrophytic species in different freshwater bodies of India and abroad (Billore and Vyas, 1981; Biswas and Calder, 1984; Cottam and Curtis, 1956; Crowder et al., 1977; Dey, 1981; Dey and Kar, 1989; Hutchinson, 1975; Kar and Barbhuiya, 2000; Mishra, 1974; Purohit and Singh, 1981; Shah and Abbas, 1979; Unni, 1971; Zutshi et al., 1980). But very little literature is available in this context in Barak valley region of Assam. The present investigation was, therefore, undertaken to study the species composition, seasonal distribution, succession and phytosociology of different aquatic macrophytes in certain wetlands of the valley.

MATERIALS AND METHODS up | previous | next | last

Monthly survey was done by quadrat method for collecting submerged aquatic macrophytes (AM), from January 1998 to December 1999. Qualitative and quantitative analysis of AM was done by Biswas and Calder (1984); Cottam and Curtis, (1956); Hutchinson (1975) and Mishra (1974). Specimens were identified up to genus/species level.

Equity and diversity status of the AM was studied using Shannon-Weaver (1949) function and the phyto-sociology was studied through X2 (chi-square) test.

RESULTS AND DISCUSSION up | previous | next | last

AM exhibited a heterogeneous assemblage of 27 species in the studied wetlands (Table 1). Of these, Eichhornia crassipes, Salvinia cucullata, Azolla pinnata, Trapa bispinosa, Jussiaea repens and Cynodon dactylon, were found to occur throughout the year. During monsoon, floating varieties of AM, viz., E. crassipes, S. cucullata, A. pinnata, Nymphaea nouchali, Nymphoides cristatum, N. indicum, Nelumbo nucifera and Hygrorhiza aristata flourished and dominated the aqua-regime at a greater depth of the water. Vetiveria zizanoides was also a monsoon variety, which was found to occur in some of the studied wetlands. Conversely, the monsoon varieties of AM were succeeded by the winter emergent varieties, viz., Eleocharis acutangula, Scirpus eriophorum, Echinochloa stagnina, Sagittaria trifolia and Polygonum flaccidum.

Significant phytosocial association had been recorded among the different AM species. E.crassipes, S. cucullata and A. pinnata were found to be associated with each other among the floating varieties. Further, Hydrilla verticillata, Vallisneria spiralis and Trapa natans (L) var. biopinosa were found to be associated together showing heterogeneity. Phytosocial association was also observed among Nymphaea nouchali, Nymphoides indicum and N. cristatum; as well as Eleocharis acutangula, Echinochloa stagnia and Scirpus eriophorum. Further, significant (P< 0.05) phytosocial association between C.dactylon and E.crassipes (X2 12.44), C. dactylon and N. indicum (X2 10.21), H. aristata and E.crassipes (X2 13.87), and H. aristata and N. cristatum (X2 18.96) was recorded during the study period. However, none of the AM species were found to be associated with Euryale ferox, possibly because of its thorny body; and, thus it formed a monospecific unit.

Calculation of species diversity in the studied wetlands revealed the following values:
Biased estimate of H' = 2.015;
Expected value, E (H') = 2.014;
Variance of H' = 1.431 E_____3)

TABLE 1: SPECIES COMPOSITION AND SEASONAL DISTRIBUTION OF AQUATIC MACROPHYTES FOUND IN THE WETLANDS OF BARAK VALLEY REGION, ASSAM. ('+': present, '-': absent)

 

Species name

J

A

N

F

E

B

M

A

R

A

P

R

M

A

Y

J

U

N

J

U

L

A

U

G

S

E

P

O

C

T

N

O

V

D

E

C

Free floating

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1. Azolla pinnata

+

+

+

+

+

+

+

+

+

+

+

+

2. Eichhornia crassipes

+

+

+

+

+

+

+

+

+

+

+

+

3. Lemna minor

-

-

-

+

+

+

+

+

+

+

-

-

4. Pistia stratiotes

-

-

-

+

+

+

+

+

+

+

-

-

5. Salvinia cucullata

+

+

+

+

+

+

+

+

+

+

+

+

Rooted floating

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6. Euryale ferox

-

-

+

+

+

-

-

-

-

-

+

+

7. Nelumbo nucifera

-

-

-

-

-

+

+

+

+

+

-

-

8. Nymphaea nouchali

-

-

-

-

-

+

+

+

+

+

-

-

9. Nymphoides cristatum

-

-

-

-

-

+

+

+

+

+

-

-

10. Nymphoides indicum

-

-

-

-

-

+

+

+

+

+

-

-

11. Trapa bispinosa

+

+

+

+

+

+

+

+

+

+

+

+

Submerged

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

12. Hydrilla verticillata

+

+

+

+

+

-

-

-

-

-

+

+

13. Nechamandra alternifolia

+

+

+

+

+

-

-

-

-

-

+

+

14. Vallisneria spiralis

+

+

+

+

-

-

-

-

-

-

+

+

Emergent

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

15. Alternantha sessiles

+

+

+

+

-

-

-

-

-

-

+

+

16. Cyperus platystylis

+

+

+

+

-

-

-

-

-

-

+

+

17. Cynodon dactylon

+

+

+

+

+

+

+

+

+

+

+

+

18. Echinochloa stagnina

+

+

+

+

-

-

-

-

-

-

+

+

19. Eleocharis acutangula

+

+

+

+

-

-

-

-

-

-

+

+

20. Enhydra fluctuans

+

+

+

+

+

+

+

-

-

-

+

+

21. Hygrorhiza aristata

-

-

-

-

+

+

+

+

+

+

-

-

22. Ipomoea aquatica

-

-

-

-

-

+

+

+

+

+

-

-

23. Jussiaea repens

+

+

+

+

+

+

+

+

+

+

+

+

24. Polygonum flaccidum

+

+

+

+

-

-

-

-

-

-

+

+

25. Scirpus eriophorum

+

+

+

+

-

-

-

-

-

-

+

+

26. Sagittaria trifolia

+

+

+

+

-

-

-

-

-

-

+

+

27. Vetiveria zizanoides

-

-

-

-

+

+

+

+

+

+

-

-

REFERENCES up | previous | next | last

  • Billore, D.K. and Vyas, I.N., 1981. Distribution and production of macrophytes in Pichhola Lake, Udaipur. Int. J. Ecol. Env. Sci., 7: 45-54.
  • Biswas, K. and Calder, C.C., 1984. Handbook of common water and marsh plants of India and Burma, xvi + 216, Bishen Singh Mahendra Pal Singh (Dehra Dun).
  • Cottam, G. and Curtis, J.T., 1956. The use of distance measures in phytosociological sampling. Ecology. 37: 151-160.
  • Crowder, A.A., Bristow, J.M., King, M.R. and Vander, K.S., 1977. Distribution, seasonality and biomass of aquatic macrophytes in Lake Opinicon. Naturaliste Can., 104: 441-456.
  • Dey, S.C. and Kar, D., 1989. Aquatic macrophytes of Lake Sone in Assam. Env. Ecol., 7(1):253-254.
  • Dey, S.C., 1981. Studies on the hydrobiological conditions of some commercially important lakes (Beels) of Kamrup district of Assam and their bearing on fish production. Final Technical Report, North-Eastern Council, Govt. of India. 177.
  • Hutchinson, G.E., 1975. A Treatise on Limnology, Vol.III: Aquatic macrophytes and attached algae. John Wiley and Sons, Inc. New York.
  • Kar, D. and Barbhuiya, M.H., 2000. Studies on the aquatic macrophytes of Chatla Haor floodplain wetland in Cachar district in Assam. Proc. Indian Science Cong. New Delhi (in press).
  • Mishra, K.C., 1974. Manual of Plant Ecology, Oxford and IBH Publishing Co. New Delhi. 491.
  • Purohit, R. and Singh, S.P., 1981. Seasonal variations in physico-chemical limnology of shallow zones of Nainital Lake. Western Himalaya. Proc. Indian Nat. Sci. Acad. 47: 194-203.
  • Shah, J.D. and Abbas, S.G., 1979. Seasonal variation in frequency, density, biomass and rate of production of aquatic macrophytes of the River Ganga at Bhagalpur, Bihar. Trop. Ecol. 20: 127-134.
  • Shannon, C.E. and Weaver, W., 1949. A mathematical theory of communications, Univ. Illinois Press, Urbana, USA.
  • Unni, K.S., 1971. An ecological study of the macrophytic vegetation of the Doodhadhari Lake, Raipur, M.P., India: (i) Distribution and seasonal changes in aquatic plants. Hydrobiol. 37: 139-155.
  • Zutshi, D.P., Subla, B.A., Khan, M.A. and Wanganeo, A., 1980. Comparative limnology of nine lakes of Jammu and Kashmir, Himalayas. Hydrobiol. 72: 101-112.
  • Address: up | previous

    Devashish Kar
    1.) Department of Life Science,
    Assam University,
    Silchar - 11,
    Assam

    Monjurul Hoque Barbhuiya
    2.) Department of Biology,
    Sonai NGHS School,
    Sonaimukh,
    Cachar,
    Assam

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