Paradise lost?
Manipur's rare Sangai deer might soon lose its only habitat
IMAGINE BEING a large mammal confined to an area of just 10 sq km. Imagine surviving genetic experiments, floods, encroachments, diseases and poachers, and that too in a wetland slowly shrinking in size. Imagine being honoured as a state animal, with festivals, newspapers and even TV channels named after you. And suddenly you find there are barely 200 of your kind left, amidst plans to take away the only habitat that nourished and protected you.
This is the story of Sangai, a critically endangered brow-antlered deer found in Manipur in a tiny speck of land, mostly grasslands locally called phumdi that float on water. South of Loktak Lake (a Ramsar site) in Moirang district lies the only known sanctuary for this deer, the Keibul Lamjao National Park (klnp). While the world’s only floating national park is spread over 40 sq km, the Sangai territory is restricted to only about 10 sq km, and it shrinks even further during the monsoon as water levels rise. According to the principal chief conservator of forests, Bala Prasad, the 2013 census revealed that only 24 Sangais were added to the population since 2003,with the total adding up to 204.
Inflated numbers
However, wildlife experts contest these numbers, even as the International Union for Conservation of Nature (iucn) has put this deer under the red list of critically endangered species. During 1970s-80s, census was conducted using mostly aerial surveys, while later surveys were ground-based. Political turmoil in the region and unstable habitats (shrinking of the floating phumdis) made it impossible to count their numbers.Ace wildlife conservationist, M K Ranjitsinh, also the chairperson of the Wildlife Trust of India (wti), says, “It is better to assume a far lesser number as census is not conducted every year in a systematic way. “He was speaking at the Institute of Bioresources and Sustainable Development, Imphal.
Kh Shamungao, a retired professor of Zoology and member of Manipur’s State Board for Wildlife, Biodiversity Strategies and Action Plan, says many of the Sangais presumed to exist are likely to be multiple counts of a small number, or excess counts along with certain hog deer. “A complex interplay of several factors in the field can result in the failure of the census method, usually leading to an over estimation,” adds Shamungao.
With about 200 Sangais spread across zoos in Delhi, Alipore and Guwahati and breeding centres in Manipur, experts say that lack of genetic diversity is largely contributing to the slow growth of the population.The first pair of Sangai was “gifted” to Alipore Zoo in Kolkata in 1956,the same year when Keibul Lamjao was accorded a “national park” status. According to Ranjitsinh, four deer were captured in 1960s after the first survey in klnp. In 1987, a total of 12 births were recorded which roughly makes it about 1.2 births a year. Currently, the National Zoological Park, Delhi, and the Assam State Zoo, Guwahati, maintain the highest stock of captive Sangais, housing 58 and 30 respectively.
Genetic oversight
Shamungao shows a trend in which captive population of the Sangai in all Indian zoos appears to increase exponentially till the 1980s, and after that their numbers begin to fall. He ascribes two reasons for this. “First, overcrowding the animals with low sanitation in the enclosures and, secondly, a possible genetic disorder or deterioration due to long inbreeding with a small population,” says Shamungao. Ranjitsinh corroborates this finding and says that some species of Sangai may have got mixed with other deer species. Similarly ,vertebrae ecologist and scientist with the Wildlife Institute of India (wii), AJ T Johnsingh, points out that animals for reintroduction should come only from the wild populations in klnp, as the animals in captivity have reduced genetic diversity. The wild ill-effects of inbreeding can further cause the population of an animal to shrink. That’s why only 24 new Sangais were born during the last decade, according to the forest department’s census. “The slow rate of population growth, high rate of infant mortality and decreased survival are the manifestation of genetic disorders. The inbreeding is commonly associated with a lowering of viability, adaptability and birth weight—a phenomenon known as inbreeding depression,” says Shamungao.
Habitat degeneration
The habitat of the Sangai is already under stress. In 1983, the Manipur government built a barrage for a multipurpose power project on the confluence of the Imphal river, Khuga river and its tributary, the Ungamel channel, south of Loktak Lake.To maintain the water and the power supply,the authorities raised the water height at th e reservoir to 762.12 m. A study on Loktak lake by nonprofit Kalpavriksh found that klnp suffered extensively as a result of the raised water level—the park area was constantly inundated by frequent flash floods, especially during the monsoon.
The study adds that the backflow effect of the Khuga river through the Ungamel channel towards the south of klnp causes a sudden water rise in the river during monsoon which hits the national park with great force. As a result, the floating biomass or phumdi gets ripped apart and the loose vegetation drifts away. “This not only reduces the vegetation cover in klnp ,but also endangers