IJCRR - 4(4), February, 2012
Pages: 32-41
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SPATIAL DISTRIBUTION AND SPECIES DIVERSITY OF MACROZOOBENTHOS IN HOKERA WETLAND, KASHMIR
Author: Idrees Yousuf Dar, G. A. Bhat
Category: General Sciences
Abstract:Analyses of the complex interrelationship among the benthic community of freshwaters have focused to a large extent on descriptions of species and their distributions in relation to environmental variables. The distribution of the diverse fauna within wetlands is extremely heterogeneous, in part a product of variable requirements for feeding, growth, and reproduction. These requirements are strongly influenced by change in the substratum and overlying water on a seasonal basis, e.g., changes in oxygen content, and in the inputs of living and dead organic matter for food. The benthic organisms either possesses adaptive mechanisms to cope with these changes enter relatively dormant stages until more physiologically amenable conditions return, move or die. The adaptive capabilities of the benthic animals to the dynamics of environmental parameters are basic to their distribution, growth and productivity and reproductive potential. The present study was carried out during May-October 2008 to make an ecological and spatial assessment of acrozoobenthic communities in a wetland of international importance. The study revealed marked difference in the ecological presence of some of the important pollution indicator Macrozoobenthos which are used to assess water quality also benthic communities are structured both by abiotic and biotic factors along the spatial and the temporal scales. Macrobenthic animals live in an environment that is influenced by eutrophication, pollution, fisheries, removal of substrate and dumping of substrate. Macro invertebrate community responses to environmental changes are useful in assessing the impact of municipal, industrial, oil and agricultural wastes from other land uses on surface waters. During present study a few species of Annelida were found to be dominant in terms of taxa and abundance across the four sites of collection, Mollusca however, were poorly represented. Insecta, although represented by one Texon namely Chironomous sp. was abundant throughout the study period at all sites.
Keywords: Biomonitoring, Benthic Community, Biological indicators, Freshwater, Nutrients, Sediments, Trophic Status, Wetland.
Full Text:
INTRODUCTION
Kashmir valley is gifted with numerous freshwater habitats. As a consequence of human interference in the catchment area as well as inside the water bodies, many of their peculiar habitats are shrinking fast. Ecology of the flatland lakes of the valley, have greatly changed due to increase in pollution load and encroachment on water surface (Chandha, 1990). The down link state of the fresh water bodies throughout the world asks for attention as they have a great importance in food supply, irrigation, cooling of environment, industrial process, drinking, washing, cooking, recreation and tourist attraction. Limnological studies in Kashmir were probably initiated by the Hutchinson (1932). After him, a number of investigation have been carried out (Das et al.,
1969; Zutshi et al., 1978; Qadri et al., 1981; Yousuf et al., 1983; Balkhi et al., 1987; Balkhi and Yousuf et al., 1990,1992,1996). A perusal of the available literature on the limnology of Kashmir waters reveals that the benthic communities, which represent an important component in aquatic food chain, have not received much attention (Pandit and Kaul, 1981; Jan, 1987 and Mir, 1995). Analysis of the complex interrelationship among the benthic community of freshwaters have focused to a large extent on descriptions of species and their distributions within lakes and streams in relation to environmental variables. Although such analysis are essential to initial evaluations of the communities, physiologically oriented experimental analyses of the regulating environmental parameters have been utilized among the benthic communities to nearly the extent that they have been in studies of planktonic communities. The population, productivity and the trophic interrelationships of the benthic fauna are poorly understood in lakes; they are somewhat better known in running water (Hynes, 1970). Macroinvertebrate community responses to environmental changes are useful in assessing the impact of municipal, industrial, oil, and agricultural wastes and impacts from other land uses on surface waters. Four types of environmental changes for which patterns of macro invertebrates community structure changes have been documented are increased inorganic micronutrients, increased organic loading, substrate alteration and toxic chemical pollution. Increased inorganic micronutrients and severe organic pollution usually result in a restriction in the variety of macro invertebrates to only the most tolerant ones and a corresponding increase in density of those tolerating the polluted conditions, usually associated with low dissolved oxygen concentration. In some cases severe organic pollution, siltation, or toxic chemical pollution may reduce or even eliminate the entire macro invertebrate community from an affected area (Needham, 1941) The types and distributions of benthic macroinvertebrates also have been widely used as indicators quality. The distribution of certain macroinvertebrates can be quite specific because many organisms often have narrow physiological tolerance ranges (Sladecek, 1973). Several characteristics of Macrobenthos make them favorable for use in monitoring ecosystem integrity (Adamus and Brandt, 1990). The present investigation is undertaken to study Macrobenthic biological community of Hokersar, a queen wetland of Kashmir.
MATERIAL AND METHODS
Samples of bottom macro fauna were collected in the months of May, July and October with the help of a 16 cm Ekman‘s Dredge (225 sq. cm. Sampling area), in triplicate at 4 sites as shown in figure 5 (I, II, III and IV). The upper 6 cm layer of the unwashed sediments was analyzed for the occurrence of benthic forms. The unrinsed samples were produced into a container and the Benthos sorted by floatation technique with sugar solution (Kajak et al., 1968). The bottom material collected by the dredge was washed through a standard sieve [0.4 mm opening mesh (256 mesh cm2 )] as recommended by Edmondson and Dinberg (1971). The contents were transferred to the labeled glass tubes and fixed in 4% formalin / 70% alcohol for detailed examination. The Macrozoobenthos were enumerated group wise and weighed in electronic balance after removing the extra moisture by means of a blotting paper. Total no. of Macrozoobenthos per meter square was calculated after Walch, 1968 using the following formula;
N = n/as x 10,000
Where
N = number of individuals / m2
n = number of organisms actually counted
a = area of transverse section of Ekman‘s Dredge (cm2 ).
s = Number of samples taken at each station The preserved material was then identified with the help of standard works (1889), Needham
(1941), Edmondson (1959), Pennak (1978), APHA (1998), and series on fauna of British India.
STUDY AREA
The present study deals with the wetland of International Importance- THE HOKERA WETLAND. Hokera Wetland is located at the Northwest Himalayan biographic province of Kashmir back of the snow dropped Pir Panchal. Hokera is a natural perennial wetland contagious to the Jhelum Basin. Hokersar is a permanent shallow wetland, situated 10 kms to the west of Srinagar on Srinagar – Baramullah highway at an altitude of 1, 584 m (a.m.s.l) and lies within the geographical coordinates of 34o 05`N 74o 42`E. It covers an area of 13.75 km2 and has a depth ranging from 0.66 – 1.22 mts. The famous wetland is fed by perennial Dudhganga stream that originates from Dudhganga watershed in Pir Panchal range of the Himalaya and Sukhnag stream from the west. Hokera is the only site with remaining reed beds of Kashmir and Pathway of 68 water fowl species like large Egret, Great crested Grebe, little cormorant, Common Shelduck, Tufted Duck and endangered white eyed Pochart, Coming from Siberia, China, Central Asia and Northern Europe. It is an important source of food, spawning ground and Nursery for fish, besides offering feeding and breeding ground to a variety of water birds. Typical marshy vegetation complexes inhabit like Typha, Phargmites, Eleocharis, Trapa and Nymphoids Species ranging from shallow water to open water aquatic flora. For studying the ecological distribution of Macrozoobenthos, 4 study sites are Chosen these are;
Site – I This is the only site at inlet where Dudhganga stream enters the Hokera wetland. It is situated near the village of Hajibagh at the entrance of the stream in the wetland.
Site – II The second site is chosen inside the wetland having open water and is only few meters away from bird watching site.
Site – III This site is also chosen inside the wetland; this site is far from bird watching site and is located in open water. Site – IV The site is located at the outlet near the village of Sozeith.
OBSERVATION AND RESULTS
Three main groups of Macrozoobenthos were mainly encountered during the investigation, viz;
A. Phylum: ANNELIDA
I. Class: Oligochaeta
1. Family; Tubificidae
i. Tubifex tubifex
ii. Limnodrilus spp.
II. Class: Hirudinidaea
1. Family: Erpobdellidae
Gammarus sp.
II. Class: Insecta 1. Family: Chironomidae i. Chironomus sp. C.
Phylum: MOLLUSCA I.
lass: Gastropoda 1. Family: Lymnaeidaea i. Lymnaea spp. II.
Class: Pelcypoda 1. Family: Sphaeridae i. Corbicula spp. Besides these a miscellaneous assemblage of water mites, turbelaria were also found during the investigation.
Spatial distribution of Macrozoobenthos Site I (Inlet)
The mean population density at this site was found to be 64.19 ind/m2 , which fluctuated from 88.88 ind/m2 in the month of May to 29.62 in the month of October. In the month of May where as lowest was recorded in the month of October. (Fig. 1).
Site II The mean population density at this site was 222.22 ind/m2 , which fluctuated from 162.96 ind/m2 in October to 266.66 ind/m2 in July. The maximum population was recorded during summer, while the minimum was recorded during autumn. Arthropoda was the most dominant group in the benthos and was followed by Annelida and Mollusca. (Fig. 2) Site III The mean population density at this site was 251.85 ind/m2 , fluctuated from 133.33 ind/m2 in October to 311.11 ind/m2 in May and July. The maximum population was recorded during summer and spring, while the minimum in autumn. Arthropods and annelids were the most dominating group in the benthos followed by Mollusca. (Fig. 3). SITE IV The mean population density at this site was 118.51 ind/m2 . The monthly population fluctuated from 103.70 ind/m2 in October to 133.33 ind/m2 in the month of July. The maximum population was recorded during summer, while the minimum in autumn. Arthropods and annelids were the most dominating groups followed by Mollusca. However, no organisms were observed during May. (Fig. 4). Qualitative and Quantative Analysis Qualitative analysis of Benthos revealed arthropoda as the dominant group contributing about 43.09% to the total macrozoobenthos followed by annelida with 22.76%, then by molluscs, 21.13% and then by others, 13.00%.
DISCUSSION
With the growth of human population the human interference in and around the water resources increase leading to the deterioration of the quality of water. Large quantities of nutrients are added through the human sewage, industrial wastes and agricultural runoff. When this occurs for a long time most of aquatic organisms perish/replaced by a few specialized organisms which are tolerant to such conditions. Since the water body is a complete ecosystem, any change in physical or chemical conditions also affects the occurrence and abundance of the organisms living there. The Hokera wetland was once regarded as the queen wetland of India and has a great importance of harbouring various types of migratory birds but due to anthropogenic process. It has greatly reduced in size and is infested with water plants; submerged emergents and free floating. It has also undergone significant changes over the years. The seasonal mean population density of Mollusca was found to be 128.38 ind./m2 that contributed to only 21.13%of the total benthos collected. Decline in the benthic fauna as a result of decreased pH have been reported in Scandinavians (Mossberg and Nyberg, 1979). Certain groups particularly Molluscs are reported to be sensitive to reduced pH (Sutcliffe and Carrick, 1973). Mossberg and Nyberg (1979) reported reduced no. of taxa in Lakes with pH<5. Collins et al. (1981) found a conspicuous difference in the composition or biomass of the infaunal invertebrates of three central Ontario Lakes in Canada that have recently become acidified. These authors then found that pH values increase in proximity to the sediments. Thus Lake Infauna are more insulated from the impact of low pH pulse than are the Littoral and stream organisms inhabiting large grained sediments. Oliver and Kelso (1983) reported that the fine grained sediments inhabited by lentic benthos have a larger capacity to buffer change in pH. Water rich in organic matter favor the pollution tolerant species like Tubifex and Limnodrilus (Kumar 1996) .the highest benthic population was recorded at site III suggesting that this site is characterized by higher organic matter than the rest of sites. The presence of Tubifex tubifex and Limnodrilus hoffmeesteri indicates a characteristic eutrophic stage. These are referred as the classical ?pollution indicators?. Both species are able to survive period of anoxia, such as occurs in wetlands during summer and winter months. Most tubificids have erythrocruorin a red blood pigment that effectively extracts oxygen dissolved in the water. According to Cooker (1954) in strongly oxygen poor waters there is often a large density of sludge worms (Tubifex and Limnodrilus) and blood worms (Chironomidae or Tendipidae ) whose blood is red with haemoglobin to make them highly proficient in getting oxygen where it is in less quantity. Grimas (1969) believed that an increase in number of filter feeders reflected an early phase of eutrophication. The decrease in grazers (snails) and the increase in filterers (mussels) from oligotrophy to meso-eutrophy conditions, which may reflect the amount of organic materials suspended in the water column. Nowadays, to assess the population level in a particular water body, not only chemical characteristics but also the biological indicators are used to monitor the pollution level in the water body. Lang (1991) and Remond et al. (1996) have categorized different benthic organisms as Oligotrophic, Mesotrophic and Eutrophic, on the basis of the trophic conditions of their habitats. This clearly indicates that the abiotic factors of a water body play a great role in determining its biocenose on this basic the benthic organisms recorded in the Hokera wetland from typical eutrophic taxa. The present investigation which revealed relatively less number of macroinvertebrates taxa as expected from such a habitat/wetland. In view of the above facts, it may be concluded that the Hokera wetland is getting eutrophicated and the physical and chemical characteristics of water at all the Sites in the water body have influenced the benthic community living there, as the organisms recorded mostly occur in eutrophic waters. The eutrophic character affects to distribution of the Macrozoobenthos. The data also reveals that site II and Site III are more polluted than the other Sites.
ACKNOWLEDGEMENT
The authors are highly thankful to Head, P. G. Department of Environmental Science, University of Kashmir, Srinagar for providing the laboratory facilities for the work undertaken.
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