Rhino breeding success in Assam

The age structure of the one-horned rhinoceros of Manas National Park in western Assam, bordering Bhutan, is pyramidal, indicating a high life expectancy and a significant increase in population.

On the other hand, the 500-square-kilometre park does not have the “widespread representation of calves and sub-adults” to maintain the population structure, unless it is supplemented through conservation relocations, 14 ^th The Assam rhinoceros estimate made in April has revealed.

Manas, a UNESCO World Heritage Site and a tiger reserve, had about 100 resident rhinos before 1990, but then a prolonged ethno-political conflict with extremist groups, who were used as herbs for weapons. was known to trade horns.

A rhino breeding program was started in 2006 under the Indian Rhino Vision 2020. This included the transfer of hand-reared rhinos from orphans to the Kaziranga National Park and Pobitora Wildlife Sanctuary, as well as the Wildlife Rehabilitation and Conservation Center in Kaziranga.

The current rhino population in the park was estimated to be 40 after the 1 and 2 April census.

A detailed census report by Manas field director Vaibhav C. Mathur states that the male-female sex ratio of the park’s rhinos is 1:1, which arrived without considering 10 calves and five sub-adults.

“The number of calves born in the wild reflects the availability of welfare factors to promote rhinos in the Manas National Park,” said the report, obtained through RTI, by environmental activist Rohit Choudhary.

“Taking into account the 1:1 adult as well as 1:1 sub-adult male to female ratio, we considered the construction of the population pyramid for rhinos in Manas for calves. This reveals the following structure: the graph is clearly indicative of a low birth rate, but also indicative of a low death rate, which means a higher life expectancy,” the report said.

But such populations could be harmed if not supplemented through translation, warns the report. “There is a need for an appropriate strategy to bring in more rhinos from other rhinoceros areas so that calves and sub-adults are more widely represented over time,” the statement said.

counting limits

The census report states that the “total count” or direct count method adopted for population estimation in Manas has some limitations.

Aggregate counts are typically used when aiming for a single species to be counted in a well-defined, specific area. This method assumes the probability of detection as one, meaning that each animal has a 100% chance of being observed during the count.

The total area is divided into smaller units or blocks, separated by natural barriers such as rivers or streams and forest tracts, which must be taken into account for population closure. This means that no animal can go in or out during the counting process, the report said.

The report noted that limitations of this method include low counting, as the assumption of a probability of identification of 1 is unrealistic, especially if the population closure cannot be established satisfactorily in a small area of ​​10–20 km. Is.

The total count requires high visibility to see the animals from afar, which is not possible in the case of “shy, secretive animals”. The level of accuracy cannot be measured even in the total count, the report said.

In Manas Park, rhinos were counted in all three categories – Bhuyanpara, Bansbari and Panbari – comprising 71 estimate blocks. Each anti-poaching camp and its surrounding area were considered a sample block, with some anti-poaching camps in close proximity merged to form a single block.

Speed ​​Limit

Meanwhile, Kaziranga National Park authorities have restricted the speed of vehicles to 40 kmph on the highway adjacent to the park. This is an annual step taken to prevent vehicles from killing the animals that exit the park during high floods.

Officials said six sensor-based cameras have been installed in the park’s nine designated animal corridors to measure the speed of vehicles and fine those violating the order.