Arignar Anna Zoological Park - Environment

Environment

The zoo is located within the Vandalur Reserve Forest area. The zoo's ecosystem consists of dry deciduous and dry evergreen scrub forest vegetation of the Eastern Ghats, a degraded forest consisting of mostly thorny bushes, receiving an average annual rainfall of 1,400 millimetres (55 in) and an average annual temperature of 26 °C (79 °F). The terrain is a gentle undulating one ranging in altitude from 10 to 100 metres (33 to 330 ft) with an average elevation of 50 metres (160 ft) above sea level. The park was designed to keep the natural vegetation of the area intact except where enclosures, roads, and structures had to be constructed. Originally a sparse scrub forest invaded by weeds, consisting of species such as Carissa sp., Gmelina sp., Eugenia sp., Acacia sp., Instia sp. and a few other dry evergreen forest species, the park's vegetation was gradually enriched by planting dry evergreen species. The entire campus has been fortified by means of a compound wall, preventing any biotic interference in the park and allowing the natural growth of vegetation, which give the park the look of a natural forest. The park is built based on the 'open zoo' concept. The exhibits were originally based on taxonomic and geographical distribution of the species, but have now been replaced by ecological niches and habitats. The order of priority is local species, followed by regional, national, and international species. The use of moats has made it possible to house predator and prey in extended enclosures that provide a panorama of wildlife. There are over 75 moated enclosures in the park. Enrichments in the form of ladders, climbing materials, etc. are provided for the animals to move around the enclosure freely.

Most of the exhibits in the zoo lie along a circular road covering about 2.5 kilometres (1.6 mi). Smaller mammals and other exhibits are located along three inner roads. The park area is dotted with large open island-type enclosures and chain-link fence, with camouflaged wet and dry moats, hidden walls, and simulated natural environment for the residents of the park.

The remaining area makes up the free-range zone—an open area which makes up the bulk of the park and where animals such as deer and jackals are left to roam free. There are more than 500 deer of different varieties and an equal number of jackals in the free-range zone. In addition, there are four enclosures for deer—each housing about 30 animals. Deer and jackals are found in equal numbers and are known for their fast-breeding ability, especially in their natural environment. The deer–jackal ratio is maintained by the 'natural method of selection'—allowing the stronger ones to prey on the weaker ones—a natural way of balancing the ecological system.

Otteri lake situated on the north-western side within the park premises acts as a roosting ground for a wide array of aquatic migratory birds such as the open-bill stork, painted stork, white ibis, grey heron, night heron, cormorants, darters, egrets, dabchicks, pelicans, great pelicans, glossy ibis and moorhen, making it a bird watchers' paradise. The 7-hectare (17-acre) lake, surrounded by a variety of trees, receives the run-off water from nearly half the area of the park and attracts a large number of migratory birds in October, November, and December. Both terrestrial and aquatic birds of about 70 species congregate here during the season. On average, around 10,000 migratory birds visit the lake each year. About 230 saplings of Barringtonia, a species native to mangrove habitats, have been planted inside the lake to attract more birds.