POPULATION STATUS, HABITAT UTILIZATION AND DISTRIBUTION OF MARSH CROCODILE Crocodylus palustris IN THE MADHAV NATIONAL PARK, SHIVPURI, MADHYA PRADESH, INDIA Arya M.* 1, Rao R. J. 2 and Mishra A. K. 3 1. Department of Zoology, Government K.R.G. P.G. (Auto.) College, Gwalior, M.P. (INDIA) 2. Conservation Biology Unit, SOS in Zoology, Jiwaji University, Gwalior, M.P. (INDIA) 3. Department of Zoology, Government S.M.S.P.G. College, Shivpuri, M.P. (INDIA) Received June 10, 2015 Accepted November 18, 2015 ABSTRACT Present study was conducted in the Madhav National Park, Shivpuri, Madhya Pradesh, India. Sakhya Sagar Lake and Madhav Lake located inside the park was selected for the study of marsh crocodile. Both the lakes provide promising habitat for mugger. Direct visual count method (basking and swimming observation), night census method and indirect method (through different signs) were used for recording numbers and approximate size of the mugger. During 2006-07 a total of 36 muggers and during 2007-08 a total of 41 individuals were counted in Sakhya Sagar Lake. In Madhav Lake 03 muggers were observed during both the study years. Population status, habitat preferred by muggers and distribution of muggers in different locations were recorded. Nests and hatchlings of marsh crocodile were also recorded during the survey. Key Words : Sakhya Sagar Lake, Madhav Lake, Crocodylus palustris, Population status, Habitat, Distribution INTRODUCTION In the Indian sub-continent, three species of crocodilians occur in different states. The Gharial (Gavialis gangeticus) belongs to the family Gavialidae and Salt-water crocodile (Crocodylus porosus) and marsh crocodile or mugger (Crocodylus palustris) belonging to the family Crocodillidae. 1 The marsh crocodile has the widest distributional range compared to any of the Asian freshwater crocodilian species. 2 This species is categorized as nationally Vulnerable subsequent to an assessment following IUCN criteria for threatened species and has the highest legal protection in India as it is listed in Schedule I of the Indian Wildlife (Protection) Act 1972. Rao numbers of crocodiles were on a shrift decline and they were placed in IUCN s Red Data Book. 3 The Government of India has taken up a longterm conservation programme for all three species of Indian crocodiles. The Government of India in collaboration with *Author for correspondence 311 FAO/UNDP developed a National Conservation Management Plan for Crocodiles. 4 The Sakhya Sagar and Madhav Lakes, jewels in the dry deciduous landscape of Madhav National Park are the life-line of plants and animals of the park. 5,6 Both the water bodies are providing ideal habitat in a limited dimension providing virtually the best location for understanding the basicsof behavioral, population status, habitat utilization patterns and distributional range of Mugger. Study area The Madhav National Park is situated in the central highlands of India. It is situated in the Shivpuri district of Madhya Pradesh on Agra- Bombay National Highway (NH-3), 115 km. south of Gwalior. Geographically, it lies between 25º 20-25º 38 N Latitude and 77º 38-77 º 57 E Longitudes and the altitude of the park is 380 to 480 m (m.s.l). The park also forms a catchment of the Sindh River, which flows along the Eastern boundary of the park.
The Sakhya Sagar Lake was created on the Manier River in the year 1918. The Sakhya Sagar Lake is also known as Chandpatha Lake, because of its semi circular moon shape. It is a large perennial man-made water body located on the South-western border of the forest inside the Madhav National Park. The Sakhya Sagar Lake is located 4 km. from Shivpuri town. This lake lies between latitude 25 25 N and longitude 77 43 E. It spreads about 309.01 hectares and has a maximum depth of about 12 meters. The depth of this lake varies from place to place and its basin shows the presence of muram, clay, black soil and sandy loam. The lake is bounded with a huge masonry wall situated along its Eastern shore. The Madhav Lake in the Madhav National Park lies between latitude 25 26 N and longitude 77 44 E. The lake is spread about 49 hectares and it is located 9.6 km. from Shivpuri town near village Ghasari. The Eastern side of the lake is bounded with masonry wall and water from this lake is used for drinking purposes. The Madhav Lake is interconnected with Sakhya Sagar Lake through a channel. Maximum depth was recorded in the center area. The Madhav Lake has steep rocky bank and is surrounded by trees and bushes. MATERIAL AND METHODS Surveys were conducted from April, 2006 to March, 2008 in Sakhya Sagar and Madhav Lakes for the assessment of the population statusand distribution of marsh crocodile. The survey was conducted by boat and walking along lake banks during the day. Direct sightings of mugger were recorded. Field binocular was used for recording numbers and approximate size of the mugger. During the survey locations of all the sighted muggers were marked on a field map. The length of muggers sighted was estimated and recorded as: adult over 120 cm, sub-adults 90-120 cm, juveniles/ yearlings 30-90 cm and hatchlings less than 30 cm. 7 Habitats preferred by the muggers in the Lakes were recorded. To determine the existence of marsh crocodiles 312 in the Sakhya Sagar and Madhav Lakes night census method was also used. In this method a spotlight was used to focus on the surface and bank of the lakes, by this shining/reflection of marsh crocodile eyes can be observed. By counting the pairs of eyes, distance between eyes, the numbers of marsh crocodiles were recorded. Observations were made at both water bodies. Basking method of locating marsh crocodiles is the most suitable only during winter season when the temperature of water of the lakes drops. Due to cooler weather and cold water marsh crocodiles come outside the lakes to bask to keep themselves warm in sunlight. Thus, counting of crocodiles becomes very easy in a particular area during this season. In summer, however, this method cannot be used effectively because crocodiles seldom get outside water. In indirect method we have collected the data through the different signs of mugger such as feacalpeallets, den or tunnel, tracks, trails and egg shells. 8 Different research instruments used for the study are Binocular (Olympus, 7 50), Global Position System (GPS) (Garmin 60), Digital Camera (Nikon, 10x optical zoom and 12 mega pixel). The Survey of India Topo sheet no. 54-G/11 was used to prepare the locality map of the water bodies. In the present study, all the observed data of marsh crocodiles were categorized on the basis of their occurrence and distribution in different locations and habitats. In the Sakhya Sagar Lake, 12 different locations namely- Landing No. 1 (L-1), Landing No. 2 (L-2), Landing No. 3 (L-3), Landing No. 4 (L-4), Landing No. 5 (L-5), Landing No. 6 (L-6), Landing No.7 (L-7), Landing No. 8 (L-8), Landing No. 9 (L-9), Landing No. 10 (L-10), Near Sailing Club (SC), Near BhadaiyaKund (BK) and in the Madhav Lake 03 locations namely- Near pump house (PH), Mound area inside water (MAW) and near Northern bank of the Lake (NB) were selected for data collection (Fig. 1).
Fig. 1 : Map of Sakhya Sagar Lake and Madhav Lake showing different location sites RESULTS AND DISCUSSION A good population of mugger was found in the Sakhya Sagar Lake. During 2006-07 a total of 36 muggers were observed in which 14 were adults, 06 were sub-adults, 06 were juveniles and 10 were hatchlings. A total of 41 individuals, comprising 15 adults, 08 subadults, 06 juveniles and 12 hatchlings were counted during 2007-08. Saxena studied the behavioural observation of marsh crocodile in 313 Madhav National Park, Shivpuri and reported sighting of 8 muggers in January 1988 9 According to earlier reports a total of 25 grown up young muggers were released in the Sakhya Sagar Lake. 10 During the 2001 a total of 9 muggers were recorded by Sharma in the Sakhya Sagar Lake and these included 6 adults, 1 sub adult and 2 hatchlings. The results of present survey are comprised in Table 1. Table 1 : Population status of the mugger (Crocodylus palustris) in Sakhya Sagar Lake Survey year Adults Sub-adults Juveniles /Yearlings Hatchlings 2006-2007 14 06 06 10 36 2007-2008 15 08 06 12 41 Venugopal and Prasad 11 studied the basking behaviour of crocodiles and established the preferred basking areas. According to them basking behaviour was classified as : Surface bask, when the crocodile observed was on the surface of the water without any movement. Pre-bask, when half to two-thirds of the body Total was still in water and basking, when the crocodile was completely out on land, exposing the entire body. The seasonality prevailed in the study area due to monsoon climate and three clear cut seasons viz. summer, winter and rains had profound influence on the habitat conditions of the muggers. The weather conditions at the
study area are most suitable for muggers. Although the water level decreases considerably at Sakhya Sagar and Madhav Lakes in summer months still there is sufficient water for the existence of muggers. The water conditions during summer season indicated that a good mugger population can live in various locations in these water bodies. Various locations and habitats observed during the survey are shown in Fig. 2. Fig. 2 : Map showing different locations utilized by marsh crocodiles for basking purpose at Sakhya Sagar and Madhav Lakes, Shivpuri, M.P., India Sakhya Sagar Lake has rocky areas, muddy soil bank and large marshy shoreline at various landing sites. The muggers were found basking on these sites. Landing No. 2, 3, 4, 5 and 10 were the preferred locations for basking. Basking muggers were also found near Bhadaiya Kund and Sailing Club. 314 Maximum muggers were found to utilize the area of Landing No. 10. This site is suitable for muggers in terms of sufficient depth, fewer disturbances and big and small submerged rocks, on which basking muggers were frequently seen in winter. Rocks were the most preferred basking substrate for
ISSN 0973-6921 Journal of Environmental Research And Development muggers. Muggers prefer to bask on midstream rocks or muddy banks.12 It was also noted that no mugger was found in the area of Landing No. 06 and 08. Perhaps these sites are not suitable for muggers due to increasing disturbance in the form of illegal fishing activities, cattle grazing, low water depth and lacking of shoreline for basking. The area of Landing No., 03, 04 and 05 were suitable for muggers due to the presence of adequate muddy and marshy shoreline for basking purpose. At Landing No. 07 and 09 Vol.10 No., October-December 2015 sand banks and rocky substrates were not found for basking. Cattle movement and grazing activities were comparatively high at these sites. At location near Bhadaiya Kund, Landing No. 01 and near Sailing Club the lake is shallow and human activities are more. So the number of muggers basking is less at these sites. Some evidence of mugger nesting was found near these sites. Survey information gathered from all the selected sites of Sakhya Sagar Lake are presented in Table 2 and Fig. 3. Table 2 : Distribution of muggers in the Sakhya Sagar Lake at different locations S/N No. of crocodiles counted 2006-07 2007-08 03 04 03 06 07 04 04 05 06 00 00 01 01 00 00 01 09 10 03 36 41 Locations 1 2 3 4 5 6 7 8 9 10 11 12 Total Near Bhadaiya Kund Landing No. 1 Landing No. 2 Landing No. 3 Landing No. 4 Landing No. 5 Landing No. 6 Landing No. 7 Landing No. 8 Landing No. 9 Landing No. 10 Near Sailing Club 10 No. of Crocodiles Count 2006-07 9 No. of Crocodiles Count 2007-08 Population count 8 7 6 5 4 3 2 1 0 BK L-1 L-2 L-3 L-4 L-5 L-6 L-7 L-8 L-9 L-10 Landing sites Fig. 3 : Mugger population at different locations in Sakhya Sagar Lake 315 SC
Constant population over the years suggests that the mugger breeds successfully in Sakhya Sagar Lake. In the present study evidence of mugger nesting was also observed in different areas of Sakhya Sagar Lake. Only one nest was seen in April, 2006 between Bhadaiya Kund and Landing No. 1 and 10 hatchlings were observed. Unfortunately some eggs were destroyed by feral dogs. In the year 2007, one mugger nest was located on the Northeastern bank of the lake near Sailing Club and another nest was located on the Landing No. 5. Successful hatching has been observed as broken eggs shells were found on the bank on two occasions. Study of nesting habitat revealed that there were no sand banks in Landing No. 1 and 5 in the Sakhya Sagar Lake and the female mugger laid eggs in hard black soil. The evidence of mugger nest was also observed by Saxena 13 as one mugger nest was located on the Southeastern bank of the lake during hatching time on 15 th June 1991 and a total of 31 eggs were found in the nest. On 17 th and 29 th June 1991, a total of 7 and 8 eggs were hatched, respectively. The breeding of mugger was also observed in this lake during 1987 when a nest was hatched on the same bank (Office records of Madhav National Park, Shivpuri). In Madhav Lake 03 muggers, adults and 01 subadult were observed during 2006-07 and 2007-08 (Table 3). Table 3 : Population status of the mugger (Crocodylus palustris)in Madhav Lake Survey year Adults Sub-adults Juveniles/Yearlings Hatchlings Total 2006-2007 01 00 00 03 2007-2008 01 00 00 03 The habitat of muggers in the Madhav Lake was characterized by deep water pools with steep rocky banks. The lake is surrounded by a number of trees and at some places grasses were also present. 14 Almost half of the area of lake is filled with lotus and other floating and submerged plants. Some rocky islands were present in the middle of this lake. These islands were covered with thick growth of vegetation. 15-18 The muggers were found basking on the rocks, on the banks and on the island. The mound area inside the water body is more suitable for basking than other sites. S/N No mugger was sighted in the area of near Pump House because this site is very close to water pumping station. 19-21 Presence of human beings and sound of the motors disturb the muggers. Another reason is National Highway 25 which is very close to this site. During the present study, the evidence of mugger nesting was not observed in Madhav Lake during both the study years perhaps due to lacking of suitable nesting places and high disturbances. 22,23 The population status of muggers in different locations of Madhav Lake is shown in Table 4 and Fig. 4. Table 4 : Distribution of muggers in the Madhav Lake at different locations Locations No. of crocodiles counted 2006-07 2007-08 1 Near pump house 00 00 2 Mound area inside water 3 Northern bank of lake 01 01 Total 03 03 316
ISSN 0973-6921 Journal of Environmental Research And Development No. of Crocodiles Count 2006-07 Vol.10 No., October-December 2015 No. of Crocodiles Count 2007-08 2 Number 1.5 1 0.5 0 Near Pump House Mound Area Inside Water Northern Bank of Lake Sites Fig. 4 : Mugger population at different locations in Madhav Lake CONCLUSION In the Sakhya Sagar and Madhav Lakes, the muggers inhabit in different depths. The water depth is having a positive influence on the muggers. The deep water usually makes the habitat more suitable due to availability of temperature gradients, food present in different depths and the movement of the water in different water levels. The deep pools are suitable for adults who breed in these pools; the young muggers prefer to live in the shallow waters to enable themselves to get food easily and to come outside the water quickly for basking. The water temperature during winter is very low making the muggers to come outside the water for basking to elevate their body temperature. When the water temperature is high during summer these animals stay most of their time in the water. In addition to the water spread area the land area away from the water-line is most suitable for muggers for basking, nesting and burrowing purposes in both the water bodies. The still waters of the lakes offer muggers a good habitat that is rich in food organisms. The marshy edges of lakes are favorite haunts of mugger, since they depend on both water and land for their activities. The food is mainly fish, amphibians, terrestrial mammals and occasionally water birds. Both the lakes in the Madhav National Park provide suitable habitat for mugger. Successful nesting and hatchling recorded in Sakhya Sagar Lake sand the number of muggers has increased during the last 5-6 years. Field observations indicated that the distributional range of the mugger is increasing in Sakhya Sagar and Madhav Lakes. This led to the decrease in the carrying capacity of the lakes and muggers often leave these lakes in search of new water body. ACKNOWLEDGEMENT Authors are highly thankful to the Director of Madhav National Park, Shivpuri, M.P., India for providing us all necessary facilities. Thanks are also due to the all field staff and office staff of Madhav National Park, who cooperated with us during our study. REFERENCES 1. Singh L.A.K., A profile of Indian crocodlies. Envis. wildlife and protected areas, Ind. Croco. Bi-ann Bull., 2(1), 1-4, (1999). 2. Whitaker R. and Whitaker Z., Ecology of the mugger crocodile. In : Crocodiles : Their ecology, management and conservation, a special publication of the crocodile specialist group. IUCN, Gland, Switzerland, 276-297, (1989). 3. Rao R.J., Management of crocodiles and turtles in wetland sanctuaries of India, Tig. Pap., 12(4), 1-5, (1985). 4. Rao R.J. and Singh L.A.K., Status and conservation of the Gharial in India, PHVA 317
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