India is rich in biodiversity and despite increasing human population, it holds various biodiverse regions, Rajasthan is the largest state of the Republic of India by area but it experiences less human population pressure when compared to the other states. For a layman, the mention of Rajasthan evokes images of deserts and dry land, but it also consists of other topographic and climatic features besides the Thar Desert in the west. The Aravali mountain range acts as a barrier for the spreading of desert to the east and so the eastern parts of Rajasthan are comparatively greener than the western dry parts. In terms of biodiversity, Rajasthan is well known for its flora and fauna. There are four famous national parks in Rajasthan, namely Keoladeo National Park, Ranthambore National Park, Desert National Park and Sariska Tiger Reserve, and a number of wildlife sanctuaries. Sariska and Ranthambhore are well known for their tiger populations, while Desert National Park and Keoladeo National Park are considered havens for many species of birds.
Keoladeo National Park (KNP) is on the easternmost end of Rajasthan, in Bharatpur district, in close proximity to Agra and Mathura districts of Uttar Pradesh. It has got its name because of the presence of an old Shiva temple, Kevladev within the boundary of the national park. Historically the area had been a hunting site for the rulers of Bharatpur. After independence many steps were taken to preserve the area and to conserve the wildlife within. In 1976 the area was declared as a bird sanctuary, and recognized as a Ramsar site. In 1982 it was raised to the status of national park and in 1985 recognized as a world heritage site. Although a variety of animals, from non-chordate to chordate, carnivores to herbivores, mammals to reptiles etc are found here but the class of animals for which KNP is known is Aves. KNP encompasses an area of around 29 km2 and holds a variety of zones like grasslands, woodlands, wetlands, swamps etc. which provide habitats to various species of birds. Therefore, it holds a magnificent avian diversity. It is home to not just resident and local resident birds of India and Rajasthan but is also an important wintering ground for migratory birds of central Asia and Eurasia. Besides the large wetlands within the boundary of the Park, the close proximity of Yamuna River in the eastern side and Gambhir, Banganga and Chambal Rivers on other sides, as well as various seasonal wetlands, flooding areas and agricultural fields around the park, KNP providesg an excellent habitat for a variety of living beings. Keoladeo National Park has vast areas of wetlands which support a variety of avifauna. In general, wetlands of tropical and temperate zones are well known for the high diversity of flora and fauna and extensive food chains due to many life favoring conditions around. KNP has a well-defined boundary and a wall has been raised all around which clearly separates the forest from the villages and agricultural fields all around the park. Wetlands of the park go through an annual drought and wetness cycle. Wetlands experience dryness from March to June while the wetness starts with early monsoon from July. The wetlands remain filled with water till February. After February water starts to recede drastically and wetlands get dry and almost empty by end-May. During wet period the water levels are maintained by both by natural and artificial means. As an administrative strategy besides monsoon rainfall, water is received artificially from nearby water dams (Ajan bund) so that the wetlands are full by the end of monsoon season. Due to this dryness-wetness cycle and seasonal variations in temperature, there are great variations in avifauna in different seasons.
The Park has become famous among national and international tourists, wildlife lovers, scientists and birdwatchers for various reasons. In recent years an increase in amateur photography and bird-watching has been noticed among people, especially youths of developing and developed cities around the nation. The proximity of KNP from some of the major cities of north and northwest India like Delhi-NCR, Agra, Jaipur etc. makes it a must-visit place for wildlife enthusiasts, photographers and birdwatchers of respective cities. The status of Keoladeo as a Ramsar site and a world heritage site also attracts people of various walks of life besides wildlife and nature lovers. KNP has also been an important place for scientists and researchers to carry our behavioral, ecological and evolutionary studies to increase our understanding of natural processes. For example various studies were carried out on now extinct central populations of migratory Siberian Cranes which once used to settle down in KNP as wintering ground.
It is very important to understand the relation of storks with KNP All the members of family ciconiidae of order cicniiformes are called storks in general. Overall there are 19 species of storks worldwide, represented by 6 different genus. Storks are wading birds characterized by long legs, long necks and massive bills. Out of 19 species of storks in the world, 8 species (represented by 5 genus), can be seen in India, 6 of which (Painted Stork, Asian Openbill stork, Black-necked stork, Woolly-necked Stork, Greater Adjutant and Lesser Adjutant) can be treated as Indian birds while two, which include European White Stork and Black Stork can be seen in India as winter visitors. Many of the stork species are of conservational importance. Painted Stork and Black-necked stork have been placed in near threatened category while Wooly-necked Stork and both the Adjutants are in threatened category. In KNP four regional and two winter visitor storks can be seen. Painted Stork, Asian Openbill Stork, Wooly-necked Stork and Black-necked Stork can be seen in KNP during respective breeding seasons while European White Stork and Black Neck Stork can be sometimes spotted as winter visitors. Painted Stork and Openbill Stork are colonial breeders while the Wooly-Necked Stork and Black-Necked Stork are solitary birds. KNP provides a very large area and favorable conditions in surroundings which makes this national park of great importance for these species of storks. The large wetlands of KNP act not just as favorable breeding sites but also as foraging areas which ensures that it is not always necessary for birds to cover long distances in search of other foraging grounds. Moreover KNP is a very large park in north India and so can be treated as source whose preservation could play a very important role in preservation of species in north Indian range.
Painted Stork, Mycteria leucocephala is one of the four species of genus Mycteria and the only species which is found in India. It has a distribution in Indian subcontinent and in south-east Asia. In Indian subcontinent the birds breed in India and Sri Lanka. In India its major distribution is in North, South and Western parts of India. In southern part the known breeding colonies are in Karnataka, Andhra Pradesh, Telangana and Tamil Nadu while in western part the known breeding colonies are in the state of Gujarat and southern Rajasthan. In north India many small and intermediate sized colonies are known from Delhi, southern Haryana (Sultanpur National park), Western and central Uttar Pradesh and eastern and south-eastern Rajasthan. , The significance of KNP comes from the fact that it holds the largest known colony of Painted Storks in north India and so becomes important from a conservation point of view keeping in mind that Painted Storks is in near threatened category with a declining population trend. Painted Stork is a colonial waterbird and has a resident migratory behavior, i.e. breeds in colonies in breeding season but adults locally migrate to surrounding areas once the chicks are grown enough. The breeding site is occupied again in next breeding season. However where and how far the birds move in non-breeding seasons still needs to be investigated in detail. Based on observations, they are considered to have good breeding site fidelity i.e. they have the tendency to come back to same breeding site again and again. However there are no well consolidated scientific studies which have confirmed this behavior. The breeding success of Painted Stork seems to be strictly correlated with the success of monsoon, as abundance of water ensures the abundance of fishes, which provide plenty of food for the good health and growth of growing chicks. This correlation between monsoon and breeding success was consolidated by the observations of Breeden and Breeden (1982) in which a drought was observed at KNP in 1979-1980. In the same season the Painted Storks skipped their breeding, indicating that birds do not want to make energy investments when the probability of good growth of chicks is very low due to shortage of food. A few observations also indicate that birds may abandon the breeding colony if surrounding conditions get highly degraded and may attempt nesting in new favorable sites. Keeping all these points in mind KNP appears to become very important and being the largest known breeding colony in North India, it can be treated as a region of rich intraspecific variation for the species.. By focusing more on KNP, from conservation point of view, genetic diversity of the species in North Indian distribution range can be maintained to some extent. Moreover even if some declines in natural ranges are seen in north India, KNP can help cover those losses either by providing habitat or by providing source individuals in any reintroduction plan in future. Due to its large size KNP can be seen as a buffer region for Painted Storks of North India. The KNP administration and the Govt. of Rajasthan should ensure that the wetlands are full by the end of monsoon even if the monsoon is weak, which would make KNP a preferred breeding and foraging site for the Painted Storks in the breeding season.
Asian openbill Anastomus oscitans is one of the two species of genus Anastomus.Asian Openbills have a wider distribution range than Painted Storks and can be seen almost all over India (except in the Himalayas) and also in Sri Lanka, Myanmar and Thailand. KNPprovides the largest breeding and foraging grounds for Openbills of North India and thus holds largest known colony of Openbills in the region. Like Painted Stork, Asian Openbill Stork is also a colonial breeder but it breeds before the onset of monsoon season. They need a pre-monsoon dry season with drying shallow marshy wetlands to initiate the breeding. Openbills primarily feed on molluscs, especially Pila species, whose concentration increases in drying wetlands. The probability of hunting mollusks increases manifold in pre and early monsoon period which ensures the better growth of chicks. Although Openbills have a wider distribution as compared to Painted Stork and the species has a conservation status of least concern, KNP has a unique role to play in maintaining intraspecific variation due to large colonies it supports. Every year at the time of breeding, birds start aggregating around potential breeding sites, eventually nesting there if the conditions are well. Like Painted Storks, the Openbills also leave their colonies after the chicks grow enough and disperse in various directions. It is considered that the dispersal distance in Openbills is very high as compared to Painted Stork. For instance some of the ringed birds were recovered around 800 km away to the east of the park. Just like for Painted Stork, KNP provides suitable habitat and foraging grounds for the Openbills and many of the trees which are occupied by Openbill are occupied by Painted storks later after monsoon. Some late breeder Openbills can be seen nesting alongside Painted Storks in post-monsoon Painted Stork breeding timing.
Wooly-necked Stork Ciconia episcopus and Black-necked stork Ephippiorhynchus asiaticus are solitary breeders and their nests can be seen in and around the park. Due to abundance of resources, KNP is a good foraging ground for these species. Efforts are required to conserve these species as the Black-necked Stork is in near threatened status and Wooly-necked stork is in vulnerable status. There are only a few available scientific studies on these species and more studies need to be carried out in KNP, keeping in mind the history of scientific studies in KNP.
It can be concluded that the Keoladeo National Park is not just a place of high avian biodiversity but can also be considered a place of high intraspecific variations within species because it has the potential to hold large number of individuals of species due to abundance of resources in and around the park. Besides the natural balance, various artificial maintenance activities by the administration have been taken to conserve the Park and the biodiversity within. Such efforts are always needed to keep the biodiversity as high as possible, keeping in mind the increased population pressure and industrial growth in the nation.
References
Breeden, S., and B. Breeden. 1982. ‘The drought of 1979-1980 at the Keoladeo Ghana Sanctuary, Bharatpur, Rajasthan,’ Journal of the Bombay Natural History Society. Bombay 79(1): 1-37.
