Genetically isolated brown bears in Pasvik Valley wake early
Brown bears are emerging from their dens in the Pasvik Valley earlier this year than ever before. The bears in Pasvik have been shown to be genetically isolated from their Norwegian neighbours to the west but not the Russian bears to the east. The disconnect, says biologist Alexander Kopatz, is likely due to human influence.
Brown bears living in the Pasvik Valley have broken all records as they leave their dens early this year, some with new cubs in tow.
The heightened activity in the Sør-Varanger region has scientists optimistic about the future of the bear population in an area that, for centuries, has remained a rare bastion of brown bear health.
“[Brown bears] were virtually extinct in most parts of Europe - except Pasvik,” says Alexander Kopatz, a biologist and wildlife researcher, whose focus is on how brown bear populations are connected. “Here [they] never died out and there always seemed to be larger populations.”
Last year studies estimated that only seven cubs were born in Norway; it’s estimated that 150 bears live in the country in total. The Sør-Varanger region is home to about 40 bears and also the largest brown bear research institute in Europe.
Bioforsk Svanhovd is the only lab in Europe certified to collect, record and study bear specimen samples and is where Kopatz conducts his research. His findings have recently revealed important genetic trends in the brown bears.
Hair and fecal matter are collected year round and catalogued in a database that provides scientists across Russia, Finland and Norway with a brown bear forensic laboratory.
“[It’s the] same as for criminals,” says Snorre Hagen, director of Bioforsk Svanhovd, referring to the tracking of individual bears’ DNA signatures across their ranges.
“Normally bear [population] estimations are based on observations,” explains Kopatz. “People see a bear and report it and you get an idea, but they are very biased and it’s very difficult to distinguish if it’s a different individual or the same individual.”
Recognizing these limitations, biologists like Kopatz today depend on genetic analysis. Collecting and analyzing 14,000 samples – from 2,000 bears – mailed in from volunteer collectors all over the north, the researchers at Bioforsk Svanhovd pieced together a detailed picture of where the bears were going throughout their lives, and who is related to whom.
Kopatz’s work soon revealed a mysterious genetic rift between the eastern and western regions of Europe’s northern fringe.
His team covered a large area from Karelia (Russia, Finland), to Västerbotten (Sweden), to Troms (Norway) – from northwestern Russia directly south, and also southwest along the Norwegian coast.
“Our studies show that the Scandinavian populations seem to be detached from the eastern bears,” Kopatz explains.
It turned out the bears weren’t interbreeding across an undefined line east of Tromsø. They were, however, migrating north and south between Russia, Finland, and eastern Norway – where there is “a relatively undisturbed area,” according to the study, the greenbelt along the Norway-Finland border.
There was no physical boundary between the eastern and western parts of the study area that would deter bears, but there was a division there anyway.
“Normally you would expect some kind of landscape barrier like bodies of water, mountains or something like that, which inhibits the movement of individuals,” says Kopatz. “But… there are no obvious geographical barriers [between the east and west]. So it brings in the other point, which is human influence, and that is most likely the case.”
He says there is no proof of human influence yet, besides the otherwise unexplained isolation of the populations.
Reindeer husbandry areas like those between bear populations have proven to cause serious population divisions in studies of wolves because of the illegal hunting associated with herders protecting their livelihoods. The authors of the bear study believe it may be the same for brown bears.
The isolation of populations that Kopatz and his co-authors found can have serious repercussions for bears’ long-term health. Inbreeding makes populations more susceptible to disease and genetic malfunctions; this is dangerous for a population that has long been one of the strongest in Europe.
One of the most relieving findings in the study for Kopatz was genetic data showing the Sør-Varanger brown bear population, so far, appears to be healthy and coping with the unexplained divide. Nonetheless, scientists are working to identify what or who is interrupting the bears from intermingling.
“It’s very important for populations that are isolated to improve connectivity,” he says.
Research shows that Pasvik has long been a cubbing hotspot for northern brown bears. This year’s record number of cubs will be subject to the same mysterious geographical disturbance that has prevented the existing generations from interbreeding across the north. With some help from researchers like Kopatz, that barrier may soon be explained and, eventually, removed.