Altitudinal Variations in the Vegetation of Ranthambhore Tiger Reserve – A Tiger Heritage of India

The Ranthambhore Tiger Reserve falls at the junction of Aravalli and Vindhyan hills in the western India, is not only important from rich vegetation point of view, but also for the fauna, particularly the Tiger, which stands jointly with Crocodile at the apex of food chain in this forest ecosystem in terrestrial and aquatic habitats respectively. The Reserve consists of rolling hilly tracts, interspersing plateaus, deep valleys, seasonal streams, lakes, tanks, artificial bunds etc. Certain deep gorges are nature´s treasure houses due to high moisture retention and cool and shady habitat. In Aravallis ranges, they are most suitable habitat for wildlife and rich in a variety of medicinal plants on which, Indian indigenous and traditional medicine system depends upon1.

Topographical Features

Ranthambhore Tiger Reserve is spread over a highly undulating topography. Well clothed rolling hills extend from Sawai Man Singh Sanctuary in the south-west to Kela Devi Sanctuary in north-east direction. The Vindhyan hills are usually flat-topped. The highest peak in Ranthambhore is 505 m (MSL) in the north-eastern part of the Reserve and falls in Vindhyan system. Aravalli ranges consist conical hills with sharp ridges, with an altitude of 215 m and above (MSL). The average elevation is approx. 350 m in the Reserve. The lateral narrow outlier of hills intersect the area in all directions, including drainage courses, and result in the formation of wide and flat valleys to narrow rocky gorges.

Forest Types and Vegetation

As per revised classification of forest types2, the forest of the reserve falls under Tropical Dry Deciduous Forests. Rich forest vegetation is usually concentrated along the eastern slopes of the Aravalli ranges from south towards north. The forest cover varies greatly in composition and quality.

Anogeissus pendula Edgew. (Locally known as Dhok) is the predominant species3 distributed almost throughout the park except some parts, forms almost pure stands at certain places. There is usually thin shrubby undergrowth. A unique characteristic of the forests of Ranthambhore is the disparity between the hot season when it is bone dry and entirely leafless, and the rainy season when it takes on a lush green and luxuriant appearance.

Altitudinal Variations

Three distinct altitudinal zones of vegetation can be identified in Ranthambhore4 however, sometimes their appearance may not be very clear in monsoon season.

1. Hilltop vegetation

On plateau, growth of Anogeissus pendula is stunted due to shallow and poor residual soil, but hill slopes and valleys have organically rich deep soil where its height reaches up to 10 m. In Ranthambhore, Dhok forests represent the climatic climax. On the hill-slopes and occasionally on the flat hilltops where soil deepness is inadequate, stretches of grassland appear.

On flat hilltops, also known as plateaus, the depth of the soil is very shallow and due to continuous erosion of the soil, edges of the hills and hill slopes get exposed with rocky surface. The vegetation is very sparse and growth of the plants is stunted. The other common species in such habitats include Sterculia urens, Boswellia serrata and Lannea coromandelica. Stemmed and bushy forms of xerophytic and succulent plant species are commonly found here. The herbaceous flora which include chiefly prostate and hardy forms thrive in the crevices of rocks where soil and moisture have accumulated.

2. Steep and gentle slope vegetation

The vegetation on the steeps slopes of hills is very sparse and the plants like Sterculia urens, Euphorbia neriifolia etc. are found scattered here and there without having any significant undergrowth due to absence of any layer of soil. The gentle slopes, however, maintain comparatively good vegetation cover due to better soil formation and water holding capacity. Typical dry deciduous elements viz. Sterculia urens, Boswellia serrata, Acacia leucophloea, A. catechu, Butea monosperma and Cassia fistula grows well in such habitats. The shrubs, undershrubs and woody climbers further make these forests impenetrable and dense. Herbs and grasses form green carpet vegetation on the slopes, particularly during rainy and post monsoon season. The grasses attain considerable height and provide camouflage cover to the wildlife.

3. Foothill vegetation

The foothills and valleys are characterized with comparatively more fertile soil and higher humidity. These habitats support comparatively thick vegetation and even some evergreen elements also exist here. The trees commonly found here are Diospyros melanoxylon, Cordia dichotoma, Manilkara hexandra, Ficus benghalensis, F. racemosa, Syzygium cumini, Mangifera indica, Flacourtia indica, Bauhinia racemosa, Bridelia retusa, Butea monosperma, Helicteres isora, Mallotus philippensis, Mitragyna parvifolia, Cassia fistula, Bombax ceiba etc. Phoenix sylvestris and Dendrocalamus strictus form dense thickets along the valleys and water channels. The rich diversity of shrubs, undershrubs, herbs, grasses and climbers show better performance and form the habitat suitable for herbivores and carnivores life-forms both for food and shelter.

A variety of species of family Cyperaceae, Poaceae and Commelinaceae not only give the gorgeous appearance to the valleys but are the good source of food and fodder for herbivores inhabiting in the reserve.

Regerences

1. Acharya, D. and Shrivastava, A. 2008. Indigenous Herbal Medicines: Tribal Formulations and Traditional Herbal Practices. Aavishkar Publishers Distributors, Jaipur. ISBN 978-81-7910-252-7.

2. Champion, H.G. and Seth, S.K. 1968. A revised survey of the forest types of India. Manager of Publications, Delhi, India.

3. Shrivastava, A.K. 2006. Biodiversity of Ranthambhore Tiger Reserve National Park, Rajasthan. Ph. D. Thesis. Jai Narain Vyas University, Jodhpur.

4. Singh, V. and Shrivastava, A.K. 2007. Biodiversity of Ranthambhore Tiger Reserve, Rajasthan. Scientific Publishers, Jodhpur. ISBN 81-7233-492-3.