Caribou may be indirectly affected by sea-ice loss in the Arctic

Oct 01, 2013
This is a female caribou and her calf near Kangerlussuaq, Greenland. Research led by Eric Post, a professor of biology at Penn State University, has linked an increasingly earlier plant growing season to the melting of arctic sea ice, a relationship that has consequences for offspring production by caribou in the area. Credit: Jeff Kerby, Eric Post lab, Penn State University

Melting sea ice in the Arctic may be leading, indirectly, to fewer caribou calf births and higher calf mortality in Greenland, according to scientists at Penn State University. Eric Post, a Penn State University professor of biology, and Jeffrey Kerby, a Penn State graduate student, have linked the melting of Arctic sea ice with changes in the timing of plant growth on land, which in turn is associated with lower production of calves by caribou in the area. The results of the study will be published in the journal Nature Communications on 1 October 2013.

Post began his observations on the relationship between the timing of calving and the start of the plant-growing season in Greenland 20 years ago. "I initially was interested simply in determining how closely timed the calving season was to the onset of vegetation green-up," Post explained, "without a thought as to how this relationship might be affected by climate change." Post added that, as his observations have continued, the data have revealed an increasingly earlier start to the plant growing season, a change that has not been matched by correspondingly earlier calving by caribou in the area. "Until this study," Post said, "identifying the environmental driver of this change has been the biggest challenge, one that we're getting a better understanding of now that we have more years of data." The ongoing decline in now has been associated with increases in local temperatures inland in many parts of the Arctic. "We therefore hypothesized that sea-ice decline was involved in local warming and the associated advancement of the growing season for plants at the study site, and so we set out to test that hypothesis," Post said.

This is a yearling caribou near Kangerlussuaq, Greenland in May. Research led by Eric Post, a professor of biology at Penn State University, has linked an increasingly earlier plant growing season to the melting of arctic sea ice, a relationship that has consequences for offspring production by caribou in the area. Credit: Jeff Kerby, Eric Post lab, Penn State University

Kerby added that archeological evidence suggests that caribou have used this area as a calving site for over 3,000 years. In late May to early June, caribou typically arrive from their west-to-east migratory journey in search of young plants to eat around the time caribou give birth. "Since plants are emerging earlier in the year, they tend to be older and past their peak nutritional value by the time the hungry caribou arrive to eat them," Kerby said. "The animals show up expecting a food bonanza, but they find that the cafeteria already has closed." The team members explained that, while plants respond to warmer temperatures and other changes in climate simply by adjusting the timing of their growth, caribou—whose reproductive cycles are timed by seasonal changes in daylight length, rather than by temperature—continue to give birth at nearly the same time during the spring when they usually do. "This scenario is what we call a trophic mismatch—a disconnect between the timing of when plants are most nutritious and the timing of when animals are most dependent on them for nutrition," Kerby said.

This is a female caribou and her calf. Research led by Eric Post, a professor of biology at Penn State University, has linked an increasingly earlier plant growing season to the melting of arctic sea ice, a relationship that has consequences for offspring production by caribou in the area. Credit: Eric Post, Penn State University

In addition to analyzing their own data, Post and Kerby also used information from a 1970s study of caribou calving and calf survival at the same site by Danish biologists Henning Thing and Bjarne Clausen. "This comparison allowed us to look for signs of trophic mismatch in the same caribou population over 30 years ago," Post said. He explained that he and Kerby used the statistically robust relationship between sea ice and the timing of to "hindcast" trophic mismatch to 1979, which they then compared to their more-recent findings. "We found an interesting contrast to the current state of caribou calving in relation to spring green-up," Post said. "Rather than a trophic mismatch, the observations by Thing and Clausen suggest a high state of trophic match associated with later onset of the plant . As a result, the data from the late 1970s indicate very high calf production in this population at that time."

A caribou calf. Credit: Eric Post, Penn State University

Post added that he and his team intend to study other ecological communities living near sea ice in future research. "Sea ice is part of a broader climate system that clearly has important effects on both and animals. Exactly how sea-ice decline might affect species interactions in this and other types of food webs on land in the Arctic is a question that deserves greater attention," Post said.

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tadchem
2 / 5 (24) Oct 01, 2013
Please advise us when this becomes a *real* problem. Aside from the fact that the Arctic sea ice is a maximum in mid-March and a minimum in mid-September, this year the minimum Arctic Sea Ice extent exceeded last year's minimum by about 40%.
David Dohbro has analyzed temperature records using an unbiassed purely statistical tool (used by stock market analysts to get rich from it's random fluctuations) called the Moving Average Convergence-Divergence (MACD) indicator. It clearly shows that surface temperature trends alternate from warming to cooling with a fairly stable 30-32 year period. The temperature trend reversed from heating to cooling in 2007, and a cooling trend can be expected until about 2040. If this holds, the Arctic Sea Ice coverage in mid-September can safely be predicted to remain significant until at least then, with no "ice-free Arctic" development.
cantdrive85
1.7 / 5 (27) Oct 01, 2013
Of course Caribou will be "indirectly" affected by climate change, without Polar Bears (due to their imminent extinction) at the top of the food chain Caribou numbers should explode.
The sky is falling, the sky is falling! Aaaaaaahhhhhhhhhhh!
deatopmg
1.6 / 5 (25) Oct 01, 2013
"Caribou may be indirectly affected by sea-ice loss in the Arctic" They also may not.

Always a qualifier in AGW silliness.

djr
3.5 / 5 (16) Oct 01, 2013
"Please advise us when this becomes a *real* problem."

Translation - I am now going to insert my head back up my ass. I do not wish to know anything about the world I live in - I am ignorant - and of course proud of it....
gregor1
1.7 / 5 (24) Oct 01, 2013
Declining sea ice has already wiped out all the unicorns....
Sinister1811
2.3 / 5 (20) Oct 02, 2013
I've always thought the islands off Antarctica would be a good place for any threatened Arctic species, if they're vulnerable to climate change. Might only be a temporary solution though.
triplehelix
1.5 / 5 (22) Oct 02, 2013
Reminds me of the time they thought global warming was killing off all the frogs. Turned out to be a virus.

Look for something similar. I suggest one in the germ line causing birthing/fertility issues if populations are decreasing.

triplehelix
1.5 / 5 (22) Oct 02, 2013
"Please advise us when this becomes a *real* problem."

Translation - I am now going to insert my head back up my ass. I do not wish to know anything about the world I live in - I am ignorant - and of course proud of it....


Translation - I am now going to insert my ego into the entire planets mechanisms and happenings. I wish to be so self important that every scientific observation is due to humans. I am conceited in believing our species alone can cause every single thing, and am of course, not proud of it.

Humans are so self important.

Here's an idea.

Nature kills off animals, at a vastly faster rate than humans.
Jimee
4 / 5 (12) Oct 02, 2013
Deniers are more pathetic and dangerous every day.
triplehelix
1.2 / 5 (20) Oct 03, 2013
Deniers are more pathetic and dangerous every day.


Worriers are so self important and more dangerous every day.

Name me one incident where humans just left it alone and it went bad.

Because I can name you thousands of things humans didn't leave alone and messed up big time.

Leave nature alone! Stop thinking we're the cause of everything!
runrig
5 / 5 (7) Oct 03, 2013
Name me one incident where humans just left it alone and it went bad.


But that's just the point.... we're not leaving it alone - the Earth's atmosphere that is. We're polluting it. Stopping or at least reducing that, is "reversing doing something" as opposed to "doing something"
thermodynamics
4 / 5 (8) Oct 03, 2013
Deniers are more pathetic and dangerous every day.


Worriers are so self important and more dangerous every day.

Name me one incident where humans just left it alone and it went bad.

Because I can name you thousands of things humans didn't leave alone and messed up big time.

Leave nature alone! Stop thinking we're the cause of everything!


Just one? I would say that Passenger Pigeons would be one of the most remarkable. Humans hunted them and left it alone and they went from darkening the skies with their flocks to extinct. You and I never got to see them because the hunters invented Punt Boats to blast them out of the skies by the thousands. How about that one?
Neinsense99
2.4 / 5 (17) Oct 05, 2013
Of course Caribou will be "indirectly" affected by climate change, without Polar Bears (due to their imminent extinction) at the top of the food chain Caribou numbers should explode.
The sky is falling, the sky is falling! Aaaaaaahhhhhhhhhhh!

I concur with the conclusion that something has already fallen, and it is quite likely that you were underneath. Safety helmets were mandated for a reason.
jsdarkdestruction
1.9 / 5 (16) Oct 06, 2013
"our species alone can cause every single thing,"
no one said that or anything close.
"Nature kills off animals, at a vastly faster rate than humans."
1. humans are a part of nature, you say "Humans are so self important."...then you wish to exclude us as being a part of nature?.....foot meet mouth.
2. yes and no, most species do die out from a mix of habitat destruction and humans directly killing them, but since we are also doing the habitat destruction for the most part it is still indirectly us killing them.
"name me one incident where humans just left it alone and it went bad."
you mean incidents we didn't start in the first place?(pollution, overhunting/harvesting, habitat destruction)
"Because I can name you thousands of things humans didn't leave alone and messed up big time." you means things we didn't pollute or destroy or overhunt or mess up in the first place? we humans already started the current incident and are now trying to stop it from getting worse.
Sinister1811
2.7 / 5 (21) Oct 06, 2013
Nature kills off animals, at a vastly faster rate than humans.


I guess nature killed off all these animals in recent times too?
http://en.wikiped...nnium_CE
pandora4real
1.2 / 5 (17) Oct 06, 2013
Articles on climate change that have a comment section are doing a great service in the fight against environmental terrorists. They have no impulse control and are always the first to spew their brain damaged claptrap. A number of us have created bots that collect those comments and correlate them, eventually usually yielding identities and locations. It's amazing what you can then do with social media and like minds that don't have anything to do with the target. And these types aren't real good at connecting up the dots- unless it's a conspiracy fantasy. Real conspiracies? Not a clue. So, keep posting, let them keep spewing and you'll start to notice their numbers dropping over the next few years.
ubavontuba
1.4 / 5 (19) Oct 06, 2013
Articles on climate change that have a comment section are doing a great service in the fight against environmental terrorists. They have no impulse control and are always the first to spew their brain damaged claptrap. A number of us have created bots that collect those comments and correlate them, eventually usually yielding identities and locations. It's amazing what you can then do with social media and like minds that don't have anything to do with the target. And these types aren't real good at connecting up the dots- unless it's a conspiracy fantasy. Real conspiracies? Not a clue. So, keep posting, let them keep spewing and you'll start to notice their numbers dropping over the next few years.
A demand for censorship accompanied by threats of violence ...hasn't the world suffered enough tyranny?

Sinister1811
2.8 / 5 (18) Oct 06, 2013
Articles on climate change that have a comment section are doing a great service in the fight against environmental terrorists.


So you're calling the commenters here terrorists, and at the same time calling for assassination of those people? Sure, you don't have anyone's personal details. lol

A demand for censorship accompanied by threats of violence ...hasn't the world suffered enough tyranny?


Yeah, but I noticed you gave a 1/5 for my comment above, when I didn't even mention climate change.
ubavontuba
1 / 5 (18) Oct 06, 2013
I guess nature killed off all these animals in recent times too?
http://en.wikiped...nnium_CE
Many of these were on their way to extinction on their own.

ubavontuba
1.4 / 5 (16) Oct 06, 2013
Articles on climate change that have a comment section are doing a great service in the fight against environmental terrorists.


So you're calling the commenters here terrorists, and at the same time calling for assassination of those people? Sure, you don't have anyone's personal details. lol

A demand for censorship accompanied by threats of violence ...hasn't the world suffered enough tyranny?


Yeah, but I noticed you gave a 1/5 for my comment above, when I didn't even mention climate change.
I think it's a mistake to blame mankind for every extinction. Mostly we're responsible for the extinction of competing and dangerous apex predators.

However, lately we've taken an active roll in preserving many species, even dangerous apex predators.