Causes for decline in tiger numbers

White Tiger - 9; pix SShukla; Chandigarh; January 20111. Diseases

Various diseases also take their toll silently on the wildlife, including the predators. Many animals die and there is no way to ascertain the cause of their death. There are certain diseases that spread like epidemic and play havoc. Diseases like Feline Panleucopania (highly contagious and can be fatal), tuberculosis, sarcosystis, etc. have led to the decimation of many animals including tigers. Health management of wildlife, a relatively new area, is totally neglected. There is an urgent need to incorporate this field in the area of wildlife conservation.

New Threat : canine distemper virus (CDV)

A new threat to wild tiger populations has surfaced in the form of a deadly virus. According to a recent study (2014) from the Wildlife Conservation Society (WCS), canine distemper virus (CDV) has the potential to be a significant driver in pushing the tigers towards extinction. While CDV has recently been shown to lead to the deaths of individual tigers, its long-term impacts on tiger populations had never before been studied, researchers said.

The authors evaluated these impacts on the Amur tiger population in Russia’s Sikhote-Alin Biosphere Zapovednik (SABZ), where tiger numbers declined from 38 individuals to 9 in the years 2007 to 2012. In 2009 and 2010, six adult tigers died or disappeared from the reserve, and CDV was confirmed in two dead tigers leading scientists to believe that CDV likely played a role in the overall decline of the population.

Joint investigations of CDV have been an ongoing focus of scientists since its first appearance in tigers in 2003. The finding shows that smaller populations of tigers were more vulnerable to extinction by CDV. Populations consisting of 25 individuals were 1.65 times more likely to decline in the next 50 years when CDV was present.

The results are profoundly disturbing for global wild tigers given that in most sites where wild tigers persist they are limited to populations of less than 25 adult breeding individuals.

2. Habitat loss and prey depletion

The key findings from many years of study of tiger population have indicated that in many sites, tigers decline in numbers because of habitat loss and prey depletion rather than being killed directly. A tiger needs to eat about 50 deer-sized animals or 6,600 pounds of living prey every year. Wherever prey-base is adequate and good protection measures are in place tiger populations reach high numbers simply because the species breeds quickly.

Prey species itself depend on conditions of the habitat. 21 tiger reserves in India out of 28 had lost about 250 square km of forest from 1997 to 2002. In the outer surround (within 10km from periphery of a tiger reserve) forest cover declined over the same period by 124 sq km in the same reserves. Tigers typically survive in what scientists call meta-populations — a source population with breeding females living in dense patches of forests — surrounded by dispersing tigers making their way into not so well kept nearby forests. Now when both core and buffer zones are under pressure, the tiger is hardly likely to be unaffected.

The National Tiger Conservation Authority (NTCA) commissioned a study by Wildlife Institute of India (WII) to show how much of India’s forests in tiger habitats are really capable of supporting the cat. In Shivaliks, comprising Corbett National Park and other areas, only 20.34 per cent were found of capable of really holding the tigers. The rest is too degraded and under pressure from human activity. Similarly, in central India, only 38.5 per cent could support tigers.

According to RPS Katwal, additional director general, wildlife in the Union ministry of environment and forest, increasing human habitation in and around forest sanctuaries, immense shortage of manpower in forest department and lucrative smuggling trade in wildlife to China and South East Asian nations are proving to be major stumbling blocks in the protection of the big cat in India. To kill tigers rich smugglers employ poor gullible villagers and they do it for a few thousand rupees

Simlipal a case study

Simlipal Tiger Reserve in Odisha (India) may soon face grave problem in terms of tiger population as the National Tiger Conservation Authority (NTCA) has pointed out an “alarmingly low prey base” due to hunting by tribals living on the fringes.

The reserve, spanning over 2,750 sq km area in Mayurbhanj district, has been in news since 2009 with Maoists (terrorists) overrunning the park. The deepening rot in the reserve seems to be touching new lows with NTCA’s Deputy Inspector General S P Yadav in his report to the state government confirmed that Similipal has a dark future with the current level of prey base.

“The prey base appears to be alarmingly low in view of recurring problems of akhand shikar (mass hunting ritual conducted between mid-January and mid-April) by tribals and sustenance hunting of ungulates. In-situ build up of prey population at Jenabil and upper Barah Kamuda (core areas of the reserve) is strongly advised,” Yadav said in his report while advising Kanha Tiger Reserve model where the in-situ mode of prey base regeneration was adopted.

According to a news report, published in Indian Express (12 March 2012), Yadav, who toured the Similipal reserve in March the same year, said that he did not see any tiger. “I did not see too many wild boars and deer, the prey of tigers. Without the prey base, how can one sustain the tigers?” he asked.

bengal_tiger_2_edThe Dehradun-based Wildlife Institute of India (WII) in the 2008 census had put the tiger numbers there between 15 and 27, a huge come down from 93-101 touted by reserve officials.

In May 2007, the motion-sensitive cameras set up by the WII for tiger census inside the reserve showed several poachers armed with bows and arrows having a free run inside upper Barah Kamuda range, a part of the core area that is supposed to house the maximum number of tigers.

3. Poor genetic diversity threat to tigers

A recent study by the Wildlife Institute of India (WII) in Ranthambore Tiger Reserve (RTR), Rajasthan, India, says tiger population in the park has shown a loss of genetic diversity over the years. “RTR tiger population is showing loss of many alleles, which may be due to an isolated population without any genetic exchange,” said WII’s Dr S P Goyal, the investigator of the report — ‘Tiger Genome: Implications in Wildlife Forensics‘. Alleles are a group of genes that decide an animal’s hair colour and immunity, among other characteristics. Study was published in Times of India (3 October 2011)

The park’s tiger population had crashed to 12 in 1992 and 13 in 2003. It bounced back to 31 in 2010 but Dharmendra Khandal, a conservation biologist, feels lower genetic diversity would prove to be a new threat.

“Urbanisation and fragmentation in tiger corridors are the reasons. Ranthambore tigers used to take the Chambal river route to reach Madhya Pradesh’s (MP) Kuno reserve. But flattening of the river banks stopped tiger dispersal between Ranthambore and MP, resulting in no gene flow between the two tiger populations,” he said.

According to tiger expert Valmik Thapar, a growing human population is leading to encroachment of large landscapes making the survival of many species difficult.

Tigers in India face extinction ‘due to lack of genetic diversity’

India is home to around 60% of the world’s wild tigers. Despite this the big cat in the country is threatened with extinction because of the downfall in the variety of their mating partners, which has resulted in lack of genetic diversity, according to a first-of-its-kind research published (15 May 2013) in the Proceedings of The Royal Society B journal.

Even in India the genetic diversity is declining fast making tigers increasingly vulnerable to extinction. Scientists have come to this conclusion after comparing the genetic data from modern tigers with those shot during the British Raj (1858-1947: period of British rule in India) in order to gain a historical perspective of genetic diversity.

The astonishing part of the study was that researchers identified a very high number of DNA variants in tigers killed during the British Raj – 93% of which were not found in the Indian tigers of today.

We found that genetic diversity has been lost dramatically compared to the Raj tigers and what diversity remains has become much more subdivided into the small (20-120 individual) populations that exist today,” says one of the lead authors, Professor Mike Bruford from the Cardiff School of Biosciences.

This is due to loss of habitat and habitat fragmentation, meaning lower population sizes, and the prevention of tigers from dispersing as they once would have, which means their gene pool is no longer mixing across the subcontinent.

This is important because tigers, like all other species, need genetic diversity to survive – especially under climate change – so what diversity remains needs to be managed properly so that the Indian tiger does not become inbred, and retains its capacity to adapt,” said Bruford.

The study points out that the size of the tiger population in India were brought to near collapse during the British Raj, the main impetus for this was mechanised trophy hunting that reduced their numbers from 40,000 to less than 1,800 in a mere 100 years.

Both conservationists and the Indian Government must appreciate that the number of tigers alone is not enough to ensure the species’ survival,” added Bruford.

They need to protect the whole spread of forest reserves because many reserves now have their own unique gene combinations, which might be useful for future breeding programmes.

This study shows that genetic diversity can be lost and a new genetic structure can arise very quickly, if the effects of population collapse and habitat fragmentation are strong enough, so quick action is needed to stymie further demographic loss,” Bruford said.

The territory occupied by the tiger has declined more than 50 per cent during the last three generations and today mating only occurs in 7 per cent of its historical territory, researchers said.

4. Degradation of habitats

Big cats need secure and disturbance-free habitat to maintain a viable population. But haphazard development activities in the landscape of the protected areas (PAs) pose big threat to tigers. For instance, Buxa Tiger Reserve is one place, which is in the midst of a high density of human population and faces heavy pressure from people living in and around it.

This is very necessary and urgent that the people living in the villages situated in and around core of PAs should be resettled somewhere else. Government of India has declared it will resettle around 50,000 families from 762 villages in the core areas of 39 tiger reserves in the country, but the pace of the process is very slow.

Villagers living on periphery of national parks put huge biotic pressure on forest by grazing cattle, extracting minor forest produce, bamboo, fuel wood and timber degrading forests. They are also responsible for forest fires.

Kishor Rithe, member, National Board for Wildlife (NBW) says, “Relocation in some 28 reserves, including Kanha, Sariska and Panna has benefited tigers and their prey, and relocation of families from Corbett increased tiger numbers by 52 per cent during 1984-2002”.

5. Illegal wildlife trade

According to Interpol $32 billion was the value of illegal wildlife trade in the world in 2011. The agency also says that this is the fastest growing illegal activity in the world. Approximate figures, prevalent in 2006, show that tigers were killed for just Rs. 5,000 in India by gullible villagers, but were sold in international market for a hefty price of up to $50,000 by big traders, middlemen and smugglers. In 2011 alone till October 48 tiger deaths were reported in India.

Nitin Desai, director (central India), Wildlife Protection Society of India (WPSI) says, “Areas around parks are easy targets for poachers. For long-term protection of tigers, these areas need to be secured. The tribals may not be killing the tigers but they are destroying its prey base.”

A bizarre incident of tiger smuggling came to light at Bangkok’s International Airport on 22 August 2010 when a Thai woman was nabbed for tiger smuggling. Authorities on the airport found a tiger cub that had been drugged and hidden alongside a stuffed toy tiger in a suitcase of this woman flying from Thailand to Iran.

The woman had checked in for her flight and her overweight bag was sent for an X-ray which showed what appeared to be a live animal inside, according to TRAFFIC, a wildlife trade monitoring group. The woman was arrested at Suvarnabhumi Airport before boarding her flight. The cub estimated to be about 3 months old.

When the animal was taken out of the bag it was already exhausted, dehydrated and couldn’t walk properly. Officials said had it passed the oversize baggage check and gone through four to five hours of travel, its chances of survival would have been slim.

6. Man-animal conflict

Bengal or Royal Bengal Tiger - 5; pix SShukla; Chandigarh; January 2011Man-animal conflict is another major factor that affects the big cats. As humans move deeper into the territory of tigers, chances of conflict between both sides increase many fold. Men and livestock often become the victim of tiger attacks. This infuriates villagers who resort to revenge killing.

The main growth in tiger numbers between the last two census exercises (1411 tigers in 2006 and 1706 in 2010) has taken place around well-protected tiger reserves which are close to their holding limit for the large predators. This means striped cats are increasingly moving closer to human populations, increasing the chances of conflict and harm to all concerned—the tigers, humans and the livestock.

7. Lack of protection infrastructure

Forest and wildlife do not figure on the priority lists of states, consequently forest departments usually suffer from the paucity of funds. This leads to delayed disbursal of money to the protection staff. Under staffing, adequate numbers of arms are not available; same is the case with vehicles and communication equipments. Patrolling vehicles are sometimes grounded just because there is no money for fuel. In addition to this many posts are lying vacant in the forest departments of the state and no efforts are being made to fulfill them. Contrary to this poachers flaunt sophisticated arms and technology. There are also cases of corrupt forest officials who connive with poachers in their sinister designs. They are said to provide information on tigers’ location in exchange for bribes.

8. Conviction rate and quantum of punishment being very meager

Catching of bigger poachers and smugglers is neither easy nor on the priority agenda of enforcement agencies. The punishment stipulated in the law is also not adequate. For instance, a person arrested with living protected animal or its body parts within the sanctuary gets an imprisonment of just a year, extendable up to six years. For those nabbed outside the park, sanctuary or any other protected area, the maximum punishment is three years in jail or Rs. 25,000 fine. This penalty is insignificant compared to the huge profits involved.

9. Rush of tourists

Tourism is another factor for decline in tiger numbers. Tourists are ever ready to pay big money to see tigers in their natural environment. Every state government wants to earn money from tourism, resultantly they often bend over backwards to accommodate the ever-increasing demands of hoteliers, travel agencies and other players of the industry. As the flow of tourists increases demand for more accommodation, roads, highways, electricity and water supply also increases. This results in cutting down of trees, fragmenting the forest tracts and forest corridors, restricting the free movement of animals from one forest area to another. Corridors between tiger reserves are important for genetic exchange and long-term survival.

For instance the Satpuda landscape in central India is spread across 14 districts in Madhya Pradesh, Maharashtra and Chhattisgarh. Around 34 per cent of this forest cover and has 15 per cent of the world’s tigers. However, this landscape is being fragmented.

10. Absence of political will

Politicians driven by vote bank politics and ignorance regarding importance of forests and wildlife often take wild decisions and sometimes do not take any. This mentality harms the entire ecosystem in general and tiger, the apex predator, in particular. They do not want to understand the basic fact that health of predators determines the health of the ecosystem which also sustains human beings. They look for immediate personal gains rather than the nation as a whole. This is the reason that there are encroachments on forest land, poachers are being sheltered, smugglers are thriving and enforcement is ineffective.

11. Lure for money or conservation

Funds amounting to millions of dollars are being pumped in the field of Tiger conservation. This has caused mushrooming of NGOs and conservationists who claim to be the biggest fighters for conservation. These organizations often struggle among themselves to get a bigger piece of tiger conservation pie. They most often work at cross purposes. There are some heads of the NGOs who even have their business interests, like forest lodges and hotels near tiger reserves. In such a scenario how anyone can trust these NGOs. Continued disappearance of tigers seems to indicate that none of them have been very effective in doing what is expected of them.