Black-tailed prairie dog threatened in Sask.

Even though some may see them as a nuisance, scientists are expressing concern about the fate of the black-tailed prairie dog.

The animal was initially as 'special concern' on Canada's endangered species list, but after a recent review it has been changed to 'threatened.'

Being confined to only 12 square kilometres of grassland in southern Saskatchewan is one of the factors that threatens this population, said Graham Forbes, a biologist from New Brunswick.

Their small geographical distribution makes them vulnerable to any big changes.

"They're vulnerable in the sense that there is not that many of them, maybe about ten thousand or so in the area," said Forbes.

Drought and disease are also to blame, he said. The animal reproduces best after a wet year, giving their offspring the highest chance of survival.

The reintroduction of the black-footed ferret into the habitat may also be playing a factor since the animal preys on the black-tail prairie dog.

But Forbes said there is no clear evidence the ferret is posing a threat to the population in Saskatchewan.

Black-footed ferrets introduced into other prairie dog populations in the United States have not posed a threat there, he said.