Habitats near river systems are more important for some caribou than previously believed..........A. U. of Florida study shows these lands are critical to successful birthing of baby Caribou............Testing two different habitats, the tussock tundra and riparian terraces, researchers found the latter has higher concentrations of shed female antlers and numerous newborn skeletons.............. The data suggests these terrace habitats are used more during some portions of the calving period than other areas traditionally viewed as primary calving terrain...........This is important because they comprise less than 10 percent of the Arctic National Wildlife Refuge calving grounds,.........These insights will prove critical in directing where new oil and gas exploration can and cannot take place as it relates to enabling the Arctic Caribou herd to prosper into the future

New bone survey method could aid long-term

 survival of Arctic caribou

news.ufl.edu

GAINESVILLE, Fla. — A study co-authored by a
 University of Florida
scientist adds critical new data for understanding
 caribou calving
 grounds in an area under consideration for oil
 exploration in
 Alaska's Arctic National Wildlife Refuge.

The research may be used to create improved
conservation
 strategies for an ecologically important area that
 has been
 under evaluation for natural resource exploration
since
enactment of the Alaska National Interest Lands
 Conservation
 Act in 1980.

By studying bone accumulations on the Arctic
 landscape,
 lead author Joshua Miller discovered rare habitats
near river
 systems are more important for some caribou than
 previously
 believed. The study appearing online today in the
journal
Proceedings of the Royal Society B shows bone
surveys
conducted on foot provide highly detailed and
 extensive
 data on areas used by caribou as birthing grounds.

"The bone surveys are adding a new piece of the
 puzzle,
giving us a way of studying how caribou use the
 landscape
 during calving and providing a longer perspective
for
evaluating the importance of different regions and
habitats," said Miller, an assistant scientist at the
Florida Museum of Natural History on the UF campus
and a Fenneman assistant research professor at the
 University of Cincinnati.

Unlikeother species in the deer family, both male and
female caribou grow antlers. Males shed them after they
 mate, while pregnant females keep their antlers until they
 calve, losing them within a day or two of giving birth.
 Newborn
 caribou calves also suffer high mortality rates within the
 first
couple days of birth. The female antlers and newborn
 skeletal
remains offer a unique biological signal for understanding
 calving
 activity, Miller said.

"This new tool has a lot of potential, and the idea that
these bones are providing new information is really exciting
 — bone surveys allow us to go into the field today and
collect historical information about ecosystems and animal
communities that are sometimes only known from a few
 years
 of observation," Miller said.

Miller recorded evidence of shed caribou antlers and
newborn
 skeletons from the Porcupine Caribou Herd in area 1002
 on
the coastal plain of the Arctic Refuge, which comprises
about
 1.5 million acres on Alaska's northeast border. Because
these high-latitude habitats are frozen nearly three-
quarters
 of the year, bones may be preserved on the landscape
 for hundreds or thousands of years, researchers said.

Testing two different habitats, the tussock tundra and
riparian terraces, researchers found the latter has higher
 concentrations of shed female antlers and numerous
newborn
 skeletons. The data suggests these terrace habitats are
used more during some portions of the calving period
 than other areas traditionally viewed as primary calving
 terrain, which is important because they comprise less
than
10 percent of the Arctic National Wildlife Refuge calving
 grounds,
 Miller said.

"Bone surveys are suggesting that these riparian zones
should
 be under special consideration as we think about how
 to
manage the Arctic Refuge and ensure this herd prospers
 in
the decades and centuries to come," Miller said.

The Porcupine Caribou Herd includes as many as 170,000
 animals that are essential parts of the delicate Arctic
ecosystem.
 These large, herbivorous, hoofed mammals are an
 important
food source for many indigenous northern peoples and
natural predators, including wolves, bears and eagles.

Anna Behrensmeyer, vertebrate paleontology curator at
 the Smithsonian Institution's National Museum of Natural
History, said that using skeletal remains as a research
tool is important because it helps scientists understand
which habitats need protection with minimal disruption to
caribou calving. It also allows researchers to collect
historical
information that may be used to better understand how
 climate
 change and other human influences have affected how
these
 animals use the landscape over time.

"We tend to think that what we see now is normal, but
we're just seeing a little bit of time," said Behrensmeyer,
who was not involved with the study. "Josh's work can
 extend
 our time window back maybe hundreds of years, so there's
the chance of seeing long-term cycles in the calving areas
 and
 also correlating those cycles with climate – if you can look
 back
 into the past, you might see what this species did to
adapt
its reproductive strategies to warmer or colder climate
periods."

Study co-authors include Patrick Druckenmiller of the
University of Alaska Fairbanks Museum and Volker Bahn
of Wright State University.

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