Page 28 - ARUBA TODAY

A28 SCIENCE
Thursday 1 december 2016
Alaska biologists research mystery of declining caribou herd

BECKY BOHRER harassing caribou so much
Associated Press that they can’t eat or must
JUNEAU, Alaska (AP) — The travel long distances to get
size of a large caribou herd away, that could have an
in Alaska’s Arctic region impact, said Layne Adams,
has dropped by more 50 a research wildlife biolo-
percent over the last three gist with the U.S. Geologi-
years, and researchers who cal Survey. Work last sum-
have tentatively ruled out mer evaluating caribou
hunting and predation as range quality compared
significant factors for the to the 1970s found no clear
decline are trying to deter- changes, Adams said.
mine why. Some Alaska hunters are
The state’s Central Arctic critical of current hunt-
herd, which roams an area ing rules that allow non-
of north-central Alaska residents to kill up to five
about the size of Ohio, hit a caribou during the hunting
peak of about 70,000 cari- season and allow the kill-
bou in 2010. ing of females that might
It fell to 50,000 in 2013. That have calves depending on
year, spring arrived late, This undated photo provided by the Alaska Department of Fish and Game shows Caribou in the them.
meaning caribou had to Western Arctic in Alaska. “Obviously hunting contrib-
trudge through snow later Associated Press utes to decline. Whether
than usual at a time when it’s a significant factor, we
their bodies are already doesn’t think predation by been changes that biolo- Arctic is seeing the effects don’t know,” said Mark
stressed and not getting wolves and bears plays gists hadn’t picked up on, of a warming climate, with Richards, executive direc-
the grasses they need for a large role in regulating like impacts to vegetation polar bears serving as a tor of the Resident Hunters
nutrition. Arctic caribou herds, and that could affect caribou poster child of sorts for the of Alaska group. “But you
Surveys by the Alaska De- biologists so far have not nutrition. “But other than change. can’t deny that hunting
partment of Fish and Game detected diseases affect- that, it’s pretty challeng- The International Union for has an effect. Otherwise,
suggest the herd dwindled ing the herd, Lenart said. ing” pinpointing a cause, Conservation of Nature they wouldn’t restrict hunt-
to about 22,000 caribou Pregnancy rates for female she said. The caribou’s estimates the worldwide ing.”
this year. There has been a caribou are down slightly diet includes mushrooms, polar bear population at The fish and game depart-
higher than normal rate of since 2013, but not alarm- lichen, willow leaves, small about 26,000 animals, but ment said it plans to recom-
death among adult female ingly so, she said. Fewer shrubs and grass-like plants there are no comparable mend an overall reduction
caribou tracked with radio adult males are tracked by called sedges. historical numbers. in the number of caribou
collars but the reason for tracking collars, making it Some of the Central Arc- Polar Bears International, that can be killed from the
that is unclear, said state more difficult to spot trends tic herd caribou may have an advocacy group, says Central Artic herd because
wildlife biologist Beth Len- in their numbers. Research- joined other herds, though the bears are traditionally it now has fewer than the
art. ers conclude that caribou the extent to which that difficult to count because 28,000 to 32,000 animals
The department does not have likely died when the may have happened is it’s expensive to survey the considered its optimal
believe hunting is a factor in sensors on their collars indi- unclear, Lenart said. The remote locations where management size.
the decline, saying caribou cate the animals have not herd’s territory covers they live. The U.S. govern- Adams said the Central
killed by hunters account moved for at least 12 hours. 44,400 square miles from ment has protected polar Arctic and other herds in
for a small portion of over- Lenart plans to review the Arctic coast to the bears and some seals, cit- the region that have expe-
all deaths. The department more closely weather data Prudhoe Bay oil fields to the ing long-term threats posed rienced recent declines all
to see if there might have southern side of the Brooks to them by declining sea reached historic highs prior
Range of mountains. ice. The U.S. Geological Sur- to their drops.
It’s not unusual for there vey is trying to understand Two other northern Alaska
to be rises and falls in the how future environmental herds, the Western Arctic
numbers of caribou in change might affect cari- and Teshekpuk, have seen
herds, but Lenart described bou habitat, food and re- declines in recent years,
the change for the Central production. though the Teshekpuk ap-
Arctic herd as “definitely a Longer periods of abun- pears to have stabilized,
steep decline.” dant food could help ani- said Lincoln Parrett, a re-
While there’s no evidence mals put on more weight search coordinator with
that climate change is af- for the winter but if summers the state Department of
fecting the herd yet, the are very buggy, with insects
Fish and Game.q