Monday, September 22, 2008

Vindhyan and Deccan Trap

The eastern and southern extremities of the Aravalli ranges in Rajasthan mark the beginning of two different geological formations. The Vindhyan hill system and the Deccan trap begin here. The Vindhyan system lies above the older formations and constitutes an unmetamorphosed column of calcareous, arenaceous and argillaceous sediments which cover a vast area, its varying depth peaking at a maximum thickness of 4,300 m. The Vindhyas in the state are part of the Great Vindhyan Basin, extending from Rohtas in Bihar to Chittorgarh in Rajasthan. The contact between the pre-Aravalli and Vindhya is marked y a regional fault, the great boundary fault, which masses the Aravallis against the lower Bhander quartzites of the Vindhyan group. This great boundary fault passes through the Ranthambhore national park in Sawai Madhopur.
Vindhyan sandstone is, by far, the most common rock found in the state, with the exception of the lower Bhander stage which, for the greater part, is calcareous. The sandstone is of a uniform fine grain, preserving the uniformity of texture and composition unchanged over long stretches. The Kaimur as well as Bhander sandstone is a fine textured, soft, easily workable stone with a deep red tint. It passes occasionally into softer shades in Karauli. These stones have a great market for building and other architectural purposes.
The topography is varied. Hill slopes change from very gentle to steep, ending in escarpments forming impregnable barriers. Extensive plateaus, locally called dangs, have been formed y the flat-topped hills of the Vindhyas. With its rich grasses and sparse tree growth, the dangs are a good pasture-land for herbivorous wild animals and domestic cattle. The Vindhyan forests of dhok and other species associated with it provide in excellent habitat for the tiger and its prey species.
The Deccan trap formation occurs in the state’s southern extremities of the Vindhyan an Aravalli ranges. Towards the end of the Mesozoic era, there were extensive eruptions an flows of lava in the peninsula which occlusive lava flows were separated by sedimentary beds. The thickness of the column of lava flows and sedimentary beds varied from place to place. The lava flows gave rise to the flat-topped hills and plateaus with their step-like terraces. The formation as a whole is called the Deccan trap.
Deccan traps are hard, tough, compact rocks. Over time, they have weathered considerably and been reduced to spheroidal blocks. These have an unaltered core and are surrounded y weathered, concentric shells. The black cotton soil of southern Rajasthan owes its existence to the prolonged weathering of the Decan trap. Although extensive area have been put under cultivation, the region continues to have pockets well stocked with teak, bamboo and mixed miscellaneous forests, and a population of wild animals.
The meeting of two different hill systems- the ancient Aravallis and the young Vindhyas with their different geological formations and physical features—has not only resulted in producing the great geological fault, but has also produced a mixed topography that is ideal for the habitation of tigers and their prey species. The herbivores find the Vindhyan grasslands on the dangs ideal foraging ground, while the sharp-ridged valleys with their ense vegetation (locally known as kho) provide safe places for tigresses to breed.
Located in these hills, near the town of Sawai Madhopur, is the ancient fort of Ranthambhore. The massive fort has had a turbulent past. Built in the 10th century by a Chauhan ruler, its thousand-year-old history has witnessed a number of sieges, battles and assaults by invaders, including a number of Mughal emperors. Ranthambhore’s history is replete with tales of bravery and valour, and among them the tenacity with which Rana Hamir kept his word at the cost o his kingdom and even his life, is part of the popular folklore.
The fort and the forests surrounding it came under the control of the rulers of Jaipur in the early-19th century,. In time, the forest area was designated a hunting preserve of Jaipur’s royal family, its wildlife otherwise strictly protected by the rulers. Though a portion of these forests was notified as the Sawai Madhopur sanctuary in 1955, the rulers continued to exercise their privilege till the withdrawal of all such facilities in 1972. In 1973, when Project Tiger was launched by the Government of Indian in collaboration with WWF, the Sawai Madhopur sanctuary was included in the list of nine tiger reserves. In 1980, the forests of Sawai Madhopur were notified a national park and it came to be known as the Ranthambhore national park.
The landscape is dominated by dbok (Anogeissus pendula) trees. Almost pure stands of dbok can be seen in the valleys and on the lower slopes. The higher slopes have a fair mix of salar (Boswellia serrata) and gum trees (Sterculia urens) with their white smooth bark. The valley and the lower slopes also have a good growth of palas (Butea monosperma) also known as the flame-of-the-for-est. Ber (Zizypbus mauritiana) and kbair (Acacia catecbu) trees grow in open, dry areas. The park is dotted with banyan (Ficus bengalensis), peepul (Ficus religiosa) and mango (Mangifera indica) trees, indicating old human settlements. Jamun (Syzygium cumini) trees grow along nullabs to form evergreen belts that provide shade during the summer months. The forests are interspersed with large, open tracts of grasslands. Some of these clearings used to be small villages with cultivated fields that were re-located in the mid-70s. Three lakes in the park have luxuriant submerged and emergent vegetation. Kbus (Vetiveria zizanoides) grass grows abundantly on the periphery of the lakes.
The close canopy of dbok trees prevents the growth of a dense ground cover that could obstruct visibility. A four-wheel drive jeep or Gypsy is best for viewing wildlife in the park. Over the years, the wild animals, including the tigers, have become quite accustomed to the vehicles. When located, they do not shy, and allow visitors a reasonably close view of their routine activities. Yet, to be able to see a tiger is never a sure bet. Their tolerance can sometimes stretch for hours, yet on other occasions, they vanish into the forests for days altogether.
Rantambhore provides an excellent habitat for herbivores. Interestingly, sambar (Cervus unicolour), the largest Indian deer, considered a shy, nocturnal and solitary animal by naturalists in other parts of India, is seen here in large herds. Herds of sambar spend their day in and around the lakes in the park, freely entering the waters to feed on submerged aquatic plants. The spotted deer or cbital (Axisaxis) does not enter the waterbodies. In the company of the langur (Presbytis entellus), it feeds on ber leaves and forest fruits. Large herds of cbital also gather o feed on fresh grasses that sprout in dried lake beds. Among antelopes, the nilgai (Baselapbus tragocamelus) is found all over the park. Its preferred habitat is open country. It can be seen in large numbers in peripheral areas around the Guda and Gilai Sagar lakes. Cbinkara (Gazella azella) is frequently seen on the plateau and on gentle slopes. The wild boar (Sus scrofa) is distributed all over the park and a large number can be seen foraging for tubers in the lake areas. Indian hare, mongoose and monitor lizard are common all over the park while civets, ratel and porcupine are noctumal creatures.
Four species of cats utilize the habitat. The leopard avoids even chance encounters with the tiger, living either on the periphery of its territory, or through selective utilization of the habitat in its absence. The caracal and jungle cat do not come in conflict with the big cats because their prey base is different. Other carnivores include the hyena, the jackal and the ratel (or honey badger).
There is a sizable population of sloth bears (Melursus ursinus) that adapt their diet with change of food according to the season: the jamun, mango, tendu and banyan produce fruit durin the summer, while the winter has only a few species like the ber that bear fruit. Sloth bear often dig for insects and termites. Large holes on the forest roads in Ranthambhore are an indication that bears are around. Sloth bears are short sighted and have poor hearing abilities. Just how poor, I once had the opportunity to observe for myself.
On a morning in February 1990, I saw a large male sloth bear in the vicinity of Rajbagh lake, moving towards Milak talao. It was about to cross the forest road when it probably saw my Gypsy. Instead of crossing the road, it started shuffling slowly along it. I followed it down the road in my Gypsy, maintaining the same pace. When we had covered about 500 m or so, I saw a full grown tigress sitting some 30-40 m ahead. Seeing the bear coming towards it, the tigress growled slowly. The bear, I could make out, neither saw the tigress nor heard its growls. The tigress rose, coughed viciously, and then rushed towards the bear. For a moment it appeared that it was about to attack the bear. Taken by surprise, the bear stood up erect on its hind legs, opened its mouth and fore-paws wide, and charged at the tigress. A battle between the two appeared inevitable, but the tigress chose to retreat hastily, leaping sideways and covering a distance of 15-20 meters before looking back. As soon as the bear saw the tigress stop, it charged again. The tigress, this time, disappeared.
The lakes in Ranthambhore provide an altogether different eco-system. A large number of cbital, sambar and wild boar are attracted by the availability of plentiful food here. While cbital graze on the grass that sprouts along the receding water in the lake beds, sambar and wild attracted by the succulent water vegetation, enter the lakes. Large territories in these high prey density areas are occupied by the most dominant male tiger. Two or three tigresses occupy smaller and mutually exclusive sub-territories within this male territory. These lakes, therefore, serve as the main natal areas, with most breeding taking place here.
I have had numerous occasions to observe the natural staging of dramatic events near these lakes, but among them the spectacular display of tact, speed and strength provided by a resident tigress in the presence of Prime Minister Rajiv Gandhi stands out. It was a cold December morning in 1985, and I was at Jogi Mahal Forest Rest House where Rajiv Gandhi was on a short holiday. We were talking about the day programme when the sudden but continuous Kbawn! Kbawn/ alarm calls of langurs, joined by the abrupt metallic Pow calls of the sambar, announced the movement of a predator in our close vicinity. Shri Gandhi, I and some others got into an open jeep and moved towards Amarai to locate the predator. We had hardly covered 300 m before we saw Noon, a resident tigress at the park, walking gracefully along the forest road. The tigress had taken her name because of her peculiar habit of moving around the lakes at noon. We started to follow her, maintaining a respectable distance between the tigress and the jeep. Though aware of our jeep, the tigress was unconcerned and kept up her own, leisurely pace. On reaching a nullab that brings in the overflow of Rajbagh lake to Padam talao, she stopped for a moment, looked around, and then left the road to enter the dry nullab bed. The alarm calls stopped and peace returned to the forest. We kept waiting in our jeep. After a while, Noon again started moving towards Rajbagh lake. It was obvious that she was hungry and looking for food. Anticipating noon’s movements, we reached Rajbagh lake ahead of her and awaited her arrival. About a dozen sambar, half submerged in water, were busy feeding on the underwater vegetation. Soon enough, Noon was there too and took cover in the tall, yellow grass. We anticipated that she would stalk the sambar from this cover and make a kill in the water. She had learnt the art of hunting in water from a dominant male tiger named Gengish who had occupied the territory before the present male took over. Instead, Noon came out of the cover and presented a broadside view to the sambar. I thought she had probably given up the idea of making a kill. The sudden appearance of the tigress on the scene created pandemonium all around. The sambar panicked and gave high pitched alarm calls. We were so close to the tigress, we could see her facial expressions. Noon selected her prey and with her eyes firmly set on it, she charged the sambar at lightning speed. The sambar bolted in different directions. The splashing of water followed by a cloud of dust raised by the stampede blurred our vision temporarily. The sambar and the tigress, all disappeared from view. It appeared as though the attempted hunt was unsuccessful because of the ‘faulty strategy’ adopted by the tigress. On moving a little further, we were surprised to see the tigress holding one adult female sambar by its neck. She was actually sitting on the sambar. Meanwhile, other visitors had joined us in their jeeps. We were now a crowd of six jeeps full with people, watching the tigress and clicking camera shutters. The tigress decided to shift her kill to the safety of the tall kbus grass before commencing her meal. Catching the sambar by its neck, she dragged it between her legs, resting twice on the way because the sambar was heavy or she was exhausted. Later, I measured the distance and found that the straight line from where Noon had charged to the point where she caught the sambar was about 150 m. Normally, a tiger brings down its prey in just one or two leaps, and it fails it abandons the attack. A tiger is not built to chase its prey. Clearly, Noon was exhibiting predatory behaviour not usually associated with tigers.
The lakes support a variety of fish, turtles and a large population of mugger or fresh water crocodiles (crocodillis palustris). Scientists believe that these reptiles evolved some 250 million years ago and have survived major environmental changes that wiped out a number of species like the dinosaurs. The crocodile’s senses are highly developed to aid its survival. Its pupils are vertical and open out in the dark to allow in more light. Underwater vision is provided by an extra, transparent eyelid. Its nostrils and eyes are located on top of the snout to facilitate a good view and comfortable breathing while lying in water. It has flaps to close its nostrils and even its ears, an adaptation aimed at its underwater life. Its teeth continue to be replaced constantly throughout its life. Perhaps the most interesting thing is that their sex is determined during the early stages of development in the eggs, by temperature! in biological laboratories, the ratio of males and females can be decided by the turning of the thermostat knob.
Of the three species of crocodiles found in India, only the marsh crocodile is found in Ranthambhore. Shy of humans, it is an elusive creature that disappears quickly when disturbed. During the winter months. It can be seen basking on the lake’s shores. Its menu consists of any animal that it can catch. NaturalistA. Dunbar Brander found the remains of leopards, wild dogs, hyenas, cbttl, sambar, four-horned antelopes, monkeys, ducks, teals, and other birds from the stomachs of crocodiles. In Rambhambhore, I have observedeven the soft-backed turtle being eaten by a crocodile. Driven by hunger, a crocodile will also attack, kill and eat human beings. Till the early ‘60s, the crocodiles at Pushkar traumatized pilgrims taking a dip to the holy lake. They were later removed from Pushkar lake.
In Ranthambhore, crocodiles mostly eat fish. They do a lot of scavenging in the vicinity of the lakes. Crocodile tracks have been frequently observed near carcasses of animals which die a normal death near the lakes. The Ranthambhore crocodiles appear to be gradually becoming more aggressive in attacking larger prey. At times they prey on young sambar that re attracted by the succulent submerged vegetation of the lake, or else kick sharply to get rid of its grip. Interesting encounters between tigers and muggers for the possession of kills have been observed around these lakes.
With a number of lakes and streams, and an abundance of fruit trees, the park is rich in birdlife,. Resident birds include the crested serpent eagle, honey buzzard. Egyptian vulture, great horned owl, brown fish owl, painted stork, black stork, white-necked stork, parakeets, peafowl and kingfishers. The golden oriole is active in summer. Paradise fly-catchers and Indian pitta visit the area during the monsoon. During winter, a large variety of migrant ducks and other waterbirds come to the reserve. Over 270 species of birds have been recorded in the area.
The dbok forests of the Vindhyan hills in the Ramgarh Vishdhan area of Bundi provide a good habitat for wild animals. The Maj river, a tributary of the Chambal, and a perennial stream called Cbautbmata ka Kbal, flow through the area. Carnivorous animals present in the area include the tiger, leopard, striped hyena, jackal and wolf. The area, earlier notified as a wildlife reserve, has now been raised to the status of a sanctuary. It has a very crucial role to play in the preservation of a healthy tiger population in Ranthambhore. There is still a partly-fragmented corridor between Ranthambhore national park and Ramgarh Vishdhari sanctuary through Sawai Madhopur sanctuary and the Kwalji closed area. The regular movement of tigers in these area has been reported. The Ramgarh Vishdhari sanctuary serves as in important connecting link between the Ranthambhore tiger reserve on one side and Bhainsrorgarh, Jawahar Sagar and Darrah wildlife sanctuaries on the other. This link is necessary for the dispersal of young tigers leaving their natal homes in search of new territories.
A linear strip of forests in the Mukundara hills of the Vindhyan system, between Rawatbhata and Gagron fort, forms an excellent wildlife area. The length of the area is trees of kbejri and babul in the rocky wasteland adjoining the agricultural fields provide in ideal habitat for bustards. They share their habitat with blackbuck, cbinkara, jackal, hare, common fox and wild boar. A large number of migratory birds visit the area and its adjoining waterbodies. Till the recent past, this area also had caracal. It has now been declared a closed area where shooting of animals is prohibited.
A long narrow strip of forest adjoining the Chambal and Brahminy rivers is rich in wildlife. A peculiarity is that the forested plateau is about 500 m to 5 km wide and 35 km long. Trees found in the forest include dbok (Anogeissuss pendula), salar, (Boswellia serrata), gurjan (Lannea coromandelica), mango (Mangifera indica), aonla (Emblica officinalis), babera (Terminalia belerica), cburel (Holoptelia integrifolia), jbinja (Baubinia racemosa), kbirni (Writia tomentosa), bija (Pterocarpus marsupitum) and semal (Bombax ceiba). The fauna is typified by sambar, cbital, cbinkara, nilgai, four-horned antelope, wild boar and hyena. The rivers have a healthy population of gbarials and muggers along with large numbers of fish and turtles.
Teak (Tectona grandis) and bamboo (Dendrocalamus strictus) forests located in the districts of Chittorgarh and Udaipur from the north-western limit of distribution of natural teak in India. The 423 sq km area was notified as a wildlife sanctuary in 1979. The area is rich in vegetation. Hundreds of species of plants are found here, and trees include teak, dbawara (Anogeissus latifolia), tendu (Diospyrus melanaxylon), salar, godal, arjun (Terminalia orjuna), kbair (Acacia catecbu), kalam (Mitragyna parviflora), cburel (Holoptelia integrifolia), mabua (Madbuca indica), babera (Terminalia belerica), sadar (Terminalia tomentos) and roban (Soymida ferbrifuga). A large number of medicinal plants and nine rare species of ferns are also found in the area.
In the past, tigers were found in the area and it was reserved for hunting by the rulers of Pratapgarh and the jagirdars of Dhariawad and Bansi. The area now has 24 species of mammals, 19 species of reptiles and 114 species of birds. Important animal species include leopard, cbausingba, mugger, ratel, pangolin and the flying squirrel. The flying squired is nocturnal by nature. It emerges from its hole at dusk and enters it before dawn. It feeds on fruits and nuts as well as the bark of some trees.
The most distinctive part of the pangolin is its armour of overlapping, protective scales. The animal curls up into an armoured ball for defending itself, exhibiting enormous muscular power. It is not possible, thereafter, to uncurl it. It usually lives in burrows built by the animal itself, and feeds upon the eggs, the young and the adults of termites and ants. It burrows are 6 to 25 feet deep, depending upon the soil condition. On entering the burrow, the animal seals the opening of the hole, making its location difficult.

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