Collecting new data on tigers in northern India

Indian tiger

The Indian tiger population is much lower than previously thought

New wildlife recording software, that works on mobile devices, could soon be used to collect tiger population data in the Ranthambore National Park (RNP) in northern India. The Park is world renowned for its tigers, and the data collected in the field will be used to understand the population dynamics of tigers and their prey items.

Traditional plaster cast method

Tigers are found in the forested areas of India, with their density varying in accordance with several key factors, most notably habitat quality and quantity, natural prey availability, levels of disturbance and poaching and the intensity of management to protect them.

The traditional method of estimating tiger populations has been to create a plaster cast of an individual’s paw print and to use it as an aid to mapping out individual territories. This is not a precise science, yet until recently has formed the basis of tiger population estimates for decades.

Survey reveals lower tiger population

Recent attempts to monitor the tiger population of India and their principal prey items made harrowing reading and sent shockwaves around the world of tiger conservation. The first nationwide survey was intensive in the extreme – more than 490,000 man days were expended to repeatedly walk over 180,000 kilometres of transect – all this in a 16-month period between 2005 and 2006.

The transects were located in a forest ‘beat’ – a recognised administrative unit of 20 square kilometres, with each beat initially scored as having high, medium, low or no tiger density. Each beat had at least five replicates to ensure no individuals were missed. Where tigers were detected remote camera traps were employed to identify individuals based upon stripe patterns and other distinguishing features. Both co-predator and prey species were identified along transects with population estimates made for all principal species.

The Indian tiger population was estimated to be around 3,500 adults – this survey showed it to be around 1,400

Prior to this survey the Indian tiger population was estimated to be around 3,500 adults – this survey showed it to be around 1,400. The difference between the two estimates is still the subject of considerable debate, but for most the ‘scientific’ one is the estimate which holds the most credence as it is based on an extensive survey supported by state of the art population prediction techniques. A revised estimate of 1,706 was broadcast at the International Tiger Conference in Delhi, March 2011. This large increase is almost certainly due in the main to the more systematic and sophisticated census techniques employed in this last survey, although some populations in reserves are benefiting from increased conservation effort.

Data collection in RNP

Ranthambore National Park (RNP), in northern India, is world renowned for its tigers.  RNP is 130km from Jaipur, in the state of Rajasthan and started life as the Sawai Madhopur Game Sanctuary and was subsequently designated as one of the Project Tiger reserves in 1973. In 1984 the Sanctuary had its boundary expanded to include two other forest reserves, increasing RNP to its current size of 392 square kilometres.

RNP is very diverse with over 300 bird species, numerous plant species (numbers vary but there are nearly 300 species of tree), rich reptile fauna and 22 species of mammal, including a relatively ‘healthy’ population of tigers.

Dr Stewart Thompson of Oxford Brookes University, along with a colleague at WildKnowledge, has developed a suite of wildlife recording software which specifically runs on mobile devices. Their aim is to use this software in the RNP to record the spatial position of tigers, their co-predators (leopard, jackal, hyena) and their principal prey items (sambar, chital). Additionally, any other attributes which may have an influence on tiger distribution (altitude, vegetation type, proximity to human habitation) will also be recorded.

Ultimately the data collected in the field will be uploaded through a web portal directly into a dedicated Geographic Information System and used to make more accurate population estimates for all species recorded. The aims of the project will be to further understand the population dynamics of tigers and their prey items and to undertake habitat mapping and accurate range size calculations for tigers and their co-predators. Ultimately the changing fortunes of tigers and their prey items in relation to elevated tourism, agriculture and climate change will be possible to calculate over time.

Written by

  • , Reader in Ecology – Spatial Ecology & Landuse Unit, Oxford Brookes University
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