Status Survey of Lakes of Eastern Rajasthan (India)

Transcription

1 Sengupta, M. and Dalwani, R. (Editors) Proceedings of Taal2007: The 12 th World Lake Conference: Status Survey of Lakes of Eastern Rajasthan (India) Dhirendra Devarshi C-8, Manju-Nikunj, Prithvi Raj Road, Jaipur , Rajasthan, India ABSTRACT Rajasthan is the largest State of India constituting 10.4% of country's geographical area. The State is poor in water resources. However, 40 % of the country's Avifauna has been reported from this State out of which about two-fifth species are dependent on wetlands or opportunistically exploit wetlands. A survey of 45 lakes of six districts of Eastern Rajasthan, which receives moderate rainfall (between cm annually), was carried out during The study area falls in semi-arid bio-geographical zone (4A and 4B provinces) of India. This area has got one of two Ramsar sites of Rajasthan, two national parks and 7 Wildlife Sanctuaries and comprises about 9% geographical area of the State. The study was conducted to prepare an inventory of all major wetlands of the region; find out avian bio-diversity of lakes of the region and to record status of aquatic vegetation, weed-infestation, and use of lakes by local communities. Occurrence of some other indicator or important aquatic species, such as sponges, crabs, mollusks, crocodile, otters was also recorded. The study revealed that the lakes in the region were relatively free from weed-infestation and point source pollution but were overexploited for fishery operations and irrigation. Majority of the lakes are man-made or man-modified lakes. Nearly all lakes get fully dried up at least once in 4-5 years. The representation of characteristic and specialized wetland/aquatic species or species that prefer specific aquatic micro-habitat, such as otters, fishing cat, storks, curlew, avocet, bitterns, rails, snipes, bluethroat, was very poor. None of the lake was found occupied by otters. Only 3 had a species of sponge. The study also recommends certain landscaping measures to enhance species richness of these lakes. Keywords: Habitat Management, Lake management, Landscape ecology, Sustainable use, Wetlands, Socio-economic use, Lake bio-diversity, Semiarid zone. INTRODUCTION The inland open water occurs in form of rivers, lakes and ponds. This resource is mainly used and managed for irrigation, providing potable water and for capture fishery. The increasing demand for water, decreasing amount of usable surface water, problem of siltation and pollution have forced concerned agencies to concentrate on issues of efficient use of lakes. These lakes also support a diverse wildlife (molluscs, fishes, amphibians, reptiles and birds). However, safeguarding interest of wildlife does appear to be an issue of priority for managers of water bodies as consumption and conservation are traditionally taken as contradictory to each other. Conservationists on the other hand insist on taking more and more lakes under protection and banning use of these for human activities. The present study tries to hit a balance between these two approaches and suggests sustainable use of lakes. OBJECTIVES OF STUDY The study was carried out with the following objectives- (i) Preparing an inventory of major water bodies (lakes and wetlands) of Eastern Rajasthan. (ii) Finding out present status of major water bodies of the study area. (iii) Finding out biological significance of surveyed lakes. (iv) Finding out lake-use pattern (Socioeconomic importance). (v) Recommending some practical measures for proper management of these lakes from the viewpoint of Bio-diversity conservation. STUDY AREA The present study was conducted in 6 Eastern Districts of Rajasthan State (India) namely Alwar, Bharatpur, Dausa, Dhaulpur, Karauli and Sawai Madhopur (Table 1 and Fig 1). These districts constitute 9% geographical area of the State and are relatively wetter in comparison to Western Rajasthan hence included in Semi-Arid bio-geographical zones of India (Rodgers and Panwar, 1988). It receives moderate rainfall (between cm annually) most of which falls in the months of monsoon (between 15th June and 15th Sept).

2 This area of Rajasthan is thickly populated in comparison to the Western parts and is inhabited by communities that mainly depend on agriculture and animal husbandry. This area has varied geographical terrain s that includes woodlands, grasslands, rivers, ravines and wetlands. The main nature reserves of Rajasthan fall in these districts (Table 2). METHODS Figure 1. Location of six eastern districts and human Table 1: District-wise Area, Location and Human Population of the Study Area S. Area District Latitude Longitude No (in km 2 ) 1 Alwar Bharatpur Dhaulpur Karauli Sawai Madhopur Dausa Total An inventory of all major water bodies was prepared for the study area. Topo-sheets published by Survey of India (1: & 1:50000), State Gazetteers and other literature was used for making the inventory. Website of 'Google Earth' was also surfed to find out water bodies of this region. Total 102 large water bodies were identified and out of these 45 were surveyed (Table 3). Each major lake was surveyed at least once during for two to three hours to find out its ecological status. Coordinates of all wetlands were recorded with the help of handheld portable GPS receiver. Details were recorded on predesigned data-sheets. No live samples were collected from lakes. Sedentary species (sponges) and species that show little mobility (freshwater molluscs) were recorded by walking along shoreline and covering at least a quarter of it. Wetland avian species were observed with the help of 12x50 prismatic binoculars. Standard filed-guide books were used for identification (Freshwater Molluscs- Subba Rao, 1989; Amphibia- Chanda, 2002, Daniel, 2002; Reptiles- Daniel, 2002, Das, 1985; Aves - Grimmett et al., 1989, Krys et al., 2000; Mammals- Prater, 1965). All lakes were surveyed during migratory season to cover migratory species though not in the same time period of the day. Some of the species may not be recorded in the period for which survey was made but it was assumed that the survey will give a gross idea about the bio-diversity supported by a lake and to some extent a meaningful inter-site comparison will also be possible. Table 2 : Nature reserves in the six Eastern Districts of Rajasthan S.No Nature Reserve Category Area (in km 2 ) District 1 Keoladeo National Park NP, IBA, Ramsar Site, World Heritage 29 Bharatpur 2. Bandh Baretha WLS WLS Bharatpur 3. Sariska Wildlife Santuary WLS, IBA,PT 557 Alwar 4. Ranthambhore National Park NP, IBA, PT 392 Sawai Madhopur 5. Keladevi Wildlife Sanctuary WLS Karauli 6. National Chambal Sanctuary WLS - S.Madhopur and Dhaulpur 7. Van Vihar WLS WLS Dhaulpur 8. Ramsagar WLS WLS Dhaulpur 9. Kesar Bagh WLS WLS Dhaulpur WLS = Wildlife sanctuary, IBA= Important Bird Area, NP = National Park, PT =Project Tiger 1499

3 Table 3: Status of Lakes in Eastern Rajasthan Number Lakes Percent site S. No District of Water surveyed coverage bodies for the during identified study survey 1 Alwar Bharatpur Dhaulpur Karauli and Sawai Madhopur 5 Dausa Total Each lake was specifically examined for presence of any sponge species (Phylum Porifera), any crab species (Arthropoda), no. of freshwater mollusc species (Mollusca), number of amphibian species (Class Amphibia), presence of crocodiles (Reptilia), wetland birds (Aves), otters and fishing cat (Mammalia). The absence or presence and number of more specialized wetland birds such as pelicans, cranes, storks, bittern, curlew, snipes, godwits, rails, fishing owl, Osprey, Greater Spotted Eagle, Whitetailed lapwing, was carefully recorded. Presence and percent cover of submerged, floating and emergent aquatic vegetation was also recorded. Human interference (number of humans around lake, number of cattle grazing around lake, number of diesel pumps drawing water) was also recorded. Information regarding nesting of large resident birds, year of overflow and desiccation was gathered from various sources such as literature, local people, and concerned government departments. RESULTS Characteristic Wetland species: Invertebrates Fresh water sponges were recorded only from 3 lakes (7% of samples, n=45). Only one species, Eunapius carteri, was observed from all three sites (Devarshi, 2006). Crabs were observed only in 3 lakes (7%). Six species of freshwater molluscs were recorded from the study area. All lakes showed presence of at least one freshwater mollusc. Bellamya bengalensis was common in lakes with relatively persistent and deep water whereas Lymnaea was partial to lakes with shallow water and aquatic vegetation. Indian Apple Snail (Pila globosa) was found only at Keoladeo Lake (Keoladeo National Park, Bharatpur)! Vertebrates Five species of amphibians have been reported from Keoladeo National Park (Vijayan 1987). However, during the study period only Skipper Frog (Rana cyanophlyctis) was found to be common and widespread. Marsh Crocodiles (Crocodylus palustris) were observed only at Gilai Sagar, Sawai Madhopur and Pachna Lake, Karauli (4%). Bayana Lake, Bharatpur lost its crocodiles in recent past. Three lakes of this region have been used by Siberian Cranes (Grus leucogeranus) for wintering as per the literature. At present, these cranes visit none of these lakes. Last record of Siberian Cranes at Keoladeo is for year Sarus cranes (Grus antigone) were observed only around 3 Lakes (Mansarovar, Alwar; Talab-e-Shahi, Dhaulpur; Keoladeo, Bharatpur). Black-necked stork (Ephippiorhynchus asiaticus), a dominant and characteristic threatened species of wetlands, was observed only in two localities (Keoladeo National Park and Talab-e-Shahi, Dhaulpur). Northern Plover (Vanellus vanellus) was observed only at Parvati Dam, Dhaulpur and Great Crested Grebe (Podiceps cristatus) at Jagar Dam, Karauli only. Painted Storks (Mycteria leucocephala), a breeding local migrant to this region, were observed only at 6 sites (13.33%). Greater Spotted Eagle (Aquila clanga) is a characteristic endangered wetland raptor. It was observed only at Keoladeo National Park. All lakes were specifically examined for signs of breeding of heron species (heronry) but no heronry except Keoladeo was found. Earlier record suggests a wetland in Deeg, Bharatpur was used as heronry but herons no longer breed here (Subramanya, 1996). Black Stork (Ciconia nigra), a winter migrant species was noticed at 4 sites (9%) only. White stork (Ciconia ciconia) was not observed at any of the lakes surveyed though has been reported from Eastern Rajasthan in the past. An endemic and endangered species- Indian Skimmer (Rynchops albicollis) was observed only at two lakes. Smooth coated otter (Lutra perspicillata) have been reported from Keoladeo National Park (Vijayan, 1987). However, during the study period otters were not observed from any of the lakes including the lakes of Keoladeo National Park. Fishing cat (Felis viverrina) is a characteristic wetland species (Prater, 1965) which was not recorded from any of the lakes except Keoladeo National Park. Only 5 lakes (11%) showed an avian bio-diversity of wetland birds above 30 species. All lakes surveyed, except those inside protected areas, were being used for irrigation. It was found that initially water is drawn through canals and later using diesel pumps. Buffaloes, cows, goats and sheep were invariably seen around all lakes outside protected areas. Herdsmen or women were found engaged in wood cutting of carrying head-loads of wood near all unprotected lakes. Fishery operations were being conducted in 18 lakes (40%) at small scale and at 3 locations on large scale (in terms of boats, man power and vehicles engaged). 12 lakes 1500

4 were totally dry at the time of visit (and were not included in sample of 45 lakes). GENERAL CONCLUSIONS The following general conclusions could be drawn from the study (i) All lakes of this region are either man-made or man modified lakes. (ii) All the lakes of this region suffer from periodic desiccation. These lakes receive water during monsoon (July to September) each year. About 40% lakes dry completely in winters (November to February) as all water is used for irrigation and the lake-bed is also used for agriculture. (iii) The cycle of desiccation for a few cases was 4-5 years (Mansarovar and Gilai Sagar, Sawai Madhopur) and almost all lakes were found to suffer total desiccation at least once in 10 years. (iv) It was found that the desiccation cycle is becoming shorter and some lakes have suffered total desiccation only in recent past after a long wet period of several decades (e.g. Ramgarh Lake dried for the first time in 1987 after a period of about 100 years). (v) Periodic droughts and excessive rainfalls are characteristic features of this region. However, there are no indications to suggest that rainfall is decreasing. Construction of anicuts & check dams and increased use for water for irrigation in the catchment area of these lakes are major contributing factors for desiccation of lakes of this region. (vi) Relatively persistent lakes are not free from human interference as they are being exploited for fishery operations. Practice of introducing seeds of exotic fishes was observed in all lakes where capture fishery operation was carried out. (vii) Weed manifestation and eutrophication were not a major problem of lakes of this area. (viii) No lake was found suffering from exploitation of water for industrial use or industrial pollution. (ix) These lakes are loosing characteristic lake or wetland fauna due to above-mentioned reasons. RECOMMENDATIONS A majority of lakes of this region have potential and their significance for supporting bio-diversity can be enhanced by proper lake management. Certain Landscape Management interventions can improve utility of these lakes for wildlife without banning their use for human beings (Devarshi and Mathur, 2006). (i) Conservation and Development of Littoral Zone Littoral zone of lakes is crucial for aquatic life. Many wetlands that support high avian bio-diversity have a littoral zone or shoreline that is relatively stable throughout the year. The net gain or loss of water in these areas is minimal for a major part of the year. Such areas occur near sluice gates, flood gates or regulators of dams or large lakes. The surplus seepage from main water body either compensates the water lost due to evaporation or infiltration or it drains out slowly. Reeds and floating vegetation (such as Nymphea) grow in these areas. Resident ducks, dabchick, jacanas, purple heron, rails, crakes, bitterns and moorhens prefer such type of habitat and also use it for nesting. A small part of each lake can be developed or managed in this form. No attempt should be made to seal the seepage, clear such an area and strengthen it with cement or masonry work. Littoral zone is the first casualty of lake developmental activities. Regulation of lakefront property is highly desirable for the support of biodiversity. Masonry works or intense shoreline development often clears vegetation to the waterline, replaces natural vegetation with turf, and artificially stabilizes the shoreline (Schueler and Simpson, 2004). No attempt should be made to change littoral zone if it already supports diverse life. A plan to enhance quality of littoral zone should be made. Suitable aquatic plants should be used and an irregular shoreline should be created rather than a smooth regular shoreline. Some birds such as sandpipers and snipes prefer open sandy or clayey shoreline. A small portion may be left open with shallow littoral zone. In case a large lake does not have a shallow area, plan should be made to develop a small area as a marshland with reedbeds and floating vegetation. (ii) Nesting and roosting islands or mounds. Wetland species (such as herons, egrets, spoonbill, cormorants, shag, storks) prefer to nest near lakes. Trees (Acacia nilotica, Mitragyna parvifolia, Tamarindus indica) on mounds or undisturbed shores are preferred for nesting. However, there is a tendency to clear all emerging mounds or islands at the time of construction or renovation of lakes perhaps to increase water-holding capacity and to provide an uninterrupted view of the entire lake. Rocky islands also provide an ideal place for roosting and resting hence no attempt should be made to bulldoze or remove such islands. New mounds may be made at appropriate locations and suitable trees may be planted on these. Rocky islands may also be created in lakes. (iii) Restriction or control on Capture Fishery The wetlands are generally rich in fish forms and there is a tendency to exploit these resources fully (Chatrath, 1992). The excessive fishery operations adversely affect the lake system i.e. the life supported by the lake and its physico-chemical properties. Fishermen also alter the natural ecosystem of lakes by introducing fast growing 1501

5 exotic hardy fishes. These exotic fishes tend to replace indigenous fishes. Although no exhaustive fish survey was carried out but information gathered from local fisherman revealed that local fishes such as Notopterus chitala, Notopterus notopterus, Mastacembalus armatus etc. are no longer found in many lakes. Fisherman also chase or shoot fish eating birds such as pelicans, cormorants and storks. It is recommended that either the capture fishery operations should be done under strict control or should be spared with at least in certain lakes. The revenue loss can be made good by finding alternative means of revenue generation such as promoting camping, boating, water sports or angling. (iv) Vantage points Wood log, branches or bamboo poles emerging out of waterline in a lake are used as a vantage point by birds like kingfishers, darter, osprey etc. These structures provide opportunity to these birds to locate their prey (fish) or to dry their wings. No attempt should be made to unnecessarily remove such structures and if not naturally present these should be provided in appropriate numbers and at appropriate places. (v) Steep Slope of Bund wall Some reinforcement is required on the steep slopes of bund walls to prevent erosion. It was observed that steep bund wall reinforced with large boulders but no masonry work to seal the gaps, supported certain birds such as Great thick-knee (Esacus recurvirostris). Bushes like milkweed (Calotropis procera) grow naturally to plug the gaps between boulders. Milkweed is a food plant for Plain tiger butterfly (Danaus chrysippus) and many other insects. The bushes make the area suitable for birds on one hand and stabilize the soil on the other. Many animals such as skinks, lizards, insects occupy these slopes and attract insectivorous birds such as shrikes. Sealing the gaps with masonry and cement creates a continuous structure with no bushes. Such slopes are not useful to insects, reptiles and birds. (vi) Shoreline development No alteration in shoreline should be done without a prior careful study. Bulkheads, riprap, retaining walls or parapet walls should be avoided unless imminently needed for bank erosion protection. No tree clearing should be allowed. (vii) Walkways and view corridors in Shoreline buffer Walkways and view corridors should be planned very carefully. Walkways or winding trails should not run along with the shoreline. Walkways should be natural or paved but not made of reinforced cement or coal tar in any case. It should touch shoreline only at one or two places giving opportunity to view shore birds. In no case driveways should be planned as has been done in case of Jalmahal (Mansagar) Lake of Jaipur. Many lakes of this region (Nindar, Karauli; Mansarovar and Mallana, Alwar; Mansarovar, Sawai Madhopur) are situated near hills or protected or reserved forests where some wildlife exists. Construction of large driveways and boulder-masonry slopes along the driveway and shore not only destroys shoreline and littoral zone but also creates an obstacle for ungulates and other wild animals that make use of these water bodies. (viii) Lakeside forest or grassland: Taking advantage of Edge effect An ecotone is a transition between two or more diverse communities. This narrow zone contains many organisms of the overlapping communities and in addition, organisms, which are characteristics of and often restricted to the ecotone. Often both the number of species and the population density of some of the species are greater in the ecotone than in the community flanking it (Odum, 1971). The tendency for increased variety and density at community junctions is known as the edge effect. To take advantage of this fact small patch of lakeside forest or grassland (or both) may be planned. Only native trees and grasses should be grown. Snags (dead standing trees) and logs (dead fallen trees) should not be removed. Watch towers may be made at appropriate locations. Such forest and grassland help in checking erosion. Many birds nest in grassland (Stone curlew, larks) and forest close to lakes. (ix) Choice of trees for plantation The careful selection of tree species is very vital for support of bird life. The exotic trees like Delonix, Eucalyptus, Silver Oak, Copper pod that are usually planted on bunds, shoreline buffer or dykes are not preferred by birds. Babul (Acacia nilotica), trees of ficus family (Ficus glomerata, Ficus benghalensis etc.), kaim (Mitragyna parvifolia), Wild Date palm (Phoenix sylvestris), Neem (Azadiachta indica) and Tamarind (Tamarindus indicus) are some trees that are used by birds for roosting and nesting (Devarshi, 2004). Mixed plantation of native trees should be done. (x) Dead storage At present the practice of leaving a dead storage in lakes is not being practiced in this region and thus all water is drawn for irrigation leaving the lake dry in the summers. This practice kills stock animals 1502

6 especially reptiles and fishes. Other opportunistic wetland species either deserts the area or die. A practice of leaving a stipulated quantity of water as dead storage may be brought in vogue. (xi) Continuity for up and downstream migration of fishes In absence of dead storage and due to construction of large anicuts and check dams, linkages of lakes with perennial and persistent water sources have been severed. This has prevented possibility of upstream and downstream migration of fishes and other life forms for natural reintroduction. Such links are very crucial for arid and semi-arid areas that observe draughts periodically and where major life forms are lost due to these dry spells. (xii) Cooperation of various agencies in lake management Management of lakes is a complex issue that warrants expertise from various disciplines including biology. The lakes in this region are not managed keeping wildlife in view and it is a wide spread assumption that human use and support to wildlife can not go hand in hand as far as Lake Management is concerned. At present lakes, their shoreline buffer and watershed are managed by different agencies and activities of many other agencies have impact on these lakes. There is virtually no coordination between these agencies. An effective coordination between Irrigation, Fishery, Municipal, Public Health and Engineering, Forest, Wasteland Development, Pollution Control, Public Works Departments, educational and research institutes may prove useful. A body comprising representatives from these departments/institutes may be constituted to plan or advise development of lakes. Devarshi, D (2004) A Study of Avifauna of the Rajasthan State (India). Ph.D. Thesis, University of Rajasthan, Jaipur Devarshi, D. and Mathur, R. (2005) Enhancing Biosignificance of Urban Lakes In Urban Lakes in India Vol. 1. National Institute of Hydrology, Roorkee Devarshi, D. (2006) Record of freshwater sponge Eunapius carteri (Bowerbank, 1863) from Keladevi Wildlife Sanctuary (Rajasthan) Zoo's Print, 21(6): Grimmett, R., Inskipp, C. and Inskipp, T. (1999) Pocket Guide to the Birds of Indian Sub-Continent. Oxford University Press Krys, K. and Perlo, B. (2000) A field Guide to the Birds of India. Om Book Service Odum, E.P. (1971) Fundamentals of Ecology. W.B. Saunders Company USA Prater, S. H. (1965) The book of Indian Mammals. Bombay Natural History Society. Bombay Rodgers, W. A. and Panwar, H. S. (1988) Planning A Wildlife Area Network in India 2 Vols. Wildlife Institute of India, Dehradun : & Schueler, T and Simpson, J. (2004), Why Urban Lakes are Different. Subba Rao, (1989) Freshwater Molluscs of India. Zoological Survey of India. Calcutta Subramanya, S. (1996), Distribution, Status and Conservation of Indian Heronries..J. Bombay Nat. Hist. Soc. 93 (3): Vijayan, V.S. (1987) Vertebrate Fauna of Keoladeo National Park, Bharatpur. Bombay Natural History Society, Bombay ACKNOWLEDGEMNTS The University Grants Commission made available funds to carry out the present study under its Minor Research Project Schemes for which I am grateful to it. I am thankful to Dr. Reena Mathur, Professor, Department of Zoology, University of Rajasthan, Jaipur and staff of MSJ College, Bharatpur who have helped me in various ways. REFERENCES Chanda, S.K. (2002) Hand book-indian Amphibians, Zoological Survey of India, Calcutta, Chatrath, K.J.S. (1992) Wetlands of India. Ashish Publishing House, New Delhi Daniel, J.C. (2002) The Book of Indian Reptiles and Amphibians. Bombay Natural History Society- Oxford University Press Das, I. (1985) Indian Turtles - A Field Guide. World Wildlife Find-India