Image copyright PA Image caption Likely reasons for the declines were poaching and the erosion of wildlife protection enforcement

The socioeconomic shocks following the collapse of the Soviet Union also affected the region's wildlife, researchers have suggested.

A study of large mammal species in Russia found that most experienced a sharp decline in numbers from 1991.

The authors said likely reasons for the declines were poaching and the erosion of wildlife protection enforcement.

Writing in Conservation Biology, they suggested international support was needed during such times.

"What we did was to prove there was a simultaneous decline for wild boar, brown bear and moose in most regions of Russia at the beginning of the 1990s, which was right after the collapse [of the Soviet Union]," explained co-author Eugenia Bragina from the University of Wisconsin-Madison, US.

"All three species are very different and have different habitat requirements," she told BBC News, indicating that the declines were not the result of a disturbance to one particular habitat.

"For example, moose prefer successional forests where there are young trees that they can forage on. Wild boar really love agricultural crops, which people in the Soviet Union used to plant for this species."

Rise of the wolf

Dr Bragina observed that despite very different ecological histories, all three species recorded a decline and these declines coincided with the collapse of the Soviet Union.

She added that as a result of the socioeconomic shock that was felt throughout the region, each species probably felt it in different ways.

"For wild boar, it was probably the loss of crops as forage because hunting managers did not plant these crops any more.

The team noted that the study of populations of eight large mammal species in Russia between 1981-2000 did show that there was one exception.

Dr Bragina said: "What was interesting was that only one species recorded an increase: the grey wolf.

"In the Soviet Union, they controlled the population of the grey wolf. There were incentives to hunt the wolves - such as free licences for ungulate species - but, of course, during the turmoil of the collapse, people had other things to worry about.

She added that the team suspect that the increase in the wolf population, which grew by 150% during the decade following the collapse of the Soviet Union, probably contributed to the decline of the moose population.

Image copyright Science Photo Library Image caption Brown bears show a decline at the beginning of the 1990s

Based on their findings, the team hypothesised: "Likely reasons for the population declines in the 1990s include poaching and the erosion of wildlife protection enforcement."

However, the data indicated a change in fortune for some of the species' populations a decade later.

"The second part of the story is good news, which is quite nice as it is not all doom and gloom," said Dr Bragina.

"We now see that the wild boar population in Russia is now larger than it was in 1991. It had collapsed and we lost about half of the population in the 1990s.

"However, it is a very adaptive species. So after a few years, it found new sources of food, somehow managed to survive and now it is doing well.

Other species like roe deer and brown bear are also showing positive signs of recovery.

But there are other species are still in decline, such as the Eurasian lynx. However, the team noted that this was a long-term trend and could not be linked to the social and economic consequences of events in the country at the beginning of the 1990s.

Dr Bragina said that the study highlighted that a sudden shock to a nation's socioeconomic infrastructure was likely to have an impact on the country's wildlife as well.

"When something like that happens we do need to pay close attention to what is happening to the wildlife," she suggested.

"Of course, when poverty increases rapidly like it did in Russia in the 1990s, there are no resources for people to pay attention to the management of wildlife.

"I think that is the moment when international conservation groups should pay attention and consider ways to preserve the wildlife. Otherwise we may find that important or iconic species are put in jeopardy."