Animals can migrate farther than evernow that the Arctic ice is melting

A research paper argues that climate change has led to more marine mammals, such as the Pacific white-sided dolphin

pictured above, changing their migratory behavior. Photo: NOAA via Wikimedia Commons

In the spring of 2010, a lone gray whale was spotted off the Mediterranean coast of Israel.

Gray whales are native to the Pacific Ocean. This was the first North Atlantic sighting of a

gray whale in about 200 years.

In recent years, many creatures have been turning up in places they don't belong. Species

that live in the Pacific Ocean have been appearing in the Atlantic, and vice versa. Northern

gannets, a North Atlantic species, have been spotted off the coast of California several

times in recent years. Meanwhile, several Pacific species of auks, a type of diving bird,

have recently been observed in the Atlantic.

Warming Climate, Melting Ice

It is a perplexing trend. While animals do occasionally wander outside of their normal

environments, scientists are starting to believe that the recent flurry of movements between

the Atlantic and Pacific ocean basins is not accidental. Rather, it may be the result of

By Washington Post, adapted by Newsela staff on 12.21.15

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climate change. Scientists argue that as Arctic ice continues to melt, northern

passageways that used to be blocked are opening up, allowing certain animals to cross

into new territories.

Marine mammals, such as whales or seals, are often physically prevented from moving

through the Arctic by sea ice, which gets in the way of their swimming

or prohibits them from coming up to breathe. Birds are capable of flying over the frozen

ocean, but they frequently choose not to do so. The ice prevents them from diving for fish.

As the climate has grown warmer, however, sea ice has begun melting, and passageways

have started opening up in the Arctic. Animals are now more free to move about as they

please, which may account for the recent movements.

Scientists Study "Faunal Exchange"

A new paper, released Nov. 30 in the journal Global Change Biology, explores the Pacific-

Atlantic migrations, which scientists call "faunal exchange."

"Animals on occasion get lost and they show up in strange places," said the paper's lead

author, whose name, ironically, is Seabird McKeon. However, he said that an unusual

pattern of faunal exchange was starting to emerge.

The paper presents a list of marine mammals and birds that the authors expect will move

between the Atlantic and Pacific more and more in the future. The list includes bird species

such as Arctic terns, common eiders, Atlantic puffins and short-tailed shearwaters.

Mammals on the list include beluga whales, ringed seals and Atlantic white-sided

dolphins. Altogether, the list contains dozens of species.

Kristin Laidre, who was not involved in the study, is a scientist at the University of

Washington's Polar Science Center. She said that the ideas presented in the paper have

been floating around the scientific community for some time.

This Has Happened Before

Laidre was the lead author on a recent paper in Conservation Biology that discussed how

the increasing effects of climate change in the Arctic were affecting marine animals there.

The paper noted the possibility of increased movement of animals in the Arctic and many

of the species discussed in Laidre's paper also appear in McKeon's new paper.

While no one can say for sure what consequences these movements will have, McKeon

and his team discuss a number of possible outcomes in their paper. They examined past

examples of faunal exchange to get a sense of how the Arctic exchange may play out.

One example the authors considered is the Great American Biotic Interchange, which

occurred several million years ago when a thin strip of land called the isthmus of Panama

formed between North and South America. The new bridge allowed land animals to cross

between the two continents for the first time. As a result, mammals from North America

invaded South America and outcompeted many of the native species there for resources.

McKeon and his team argue that a similar outcome is a possible with species crossing

from the Pacific to the Atlantic, and vice versa.

Food Chains Get Rattled

Additionally, faunal exchange can greatly affect food webs, the complex network of

relationships between predators and prey. McKeon and his team discussed killer whales

as a recent example. They explained that killer whales recently moved into ice-free areas

of Hudson Bay, a large body of water in Canada. The whales were seen preying upon

Arctic marine mammals in Hudson Bay, altering the balance of the food web there.

Faunal exchange may lead to genetic changes as well. As animals move to new territories

and mix with new species, different species may begin to interbreed, changing their

genetic makeup.

McKeon said that scientists should watch closely as animals move about in the Arctic to

better understand faunal exchange and its effects. This can help inform conservation

tactics moving forward, including the need for updated international conservation

agreements.

Do Animals Need More Protection?

Kirsten Oleson is a professor of ecological economics at the University of Hawaii and is

one of the paper's co-authors. She said that there are currently few protections for Arctic

animals because the area is blocked off by ice. However, she noted that as access

increases and other animals start passing through the Arctic, "new environmental

protections may need to be put in place."

At this point, though, scientists can only wait and see. Most scientists seem to agree that

faunal exchange between the Pacific and Atlantic is already occurring, and will only

increase as more passages open up in the Arctic, but the exact effects of faunal exchange

remain to be seen.

Quiz

1 Which sentence from the article BEST supports the idea that scientists have long been

interested in the movement of animals?

(A) In the spring of 2010, a lone gray whale was spotted off the Mediterranean

coast of Israel.

(B) Gray whales are native to the Pacific Ocean.

(C) This was the first North Atlantic sighting of a gray whale in about 200 years.

(D) In recent years, many creatures have been turning up in places they don't

belong.

2 Which paragraph from the section "Scientists Study Faunal Exchange" provides the BEST

evidence that scientists have made forecasts about "faunal exchange"?

3 Read the sentence from the section "Scientists Study Faunal Exchange."

She said that ideas presented in the paper have been floating around

the scientific community for some time.

What does the phrase "floating around" mean?

(A) moving without any specific direction

(B) being considered but not completely accepted by

(C) moving from one position to another

(D) being considered but not having a purpose

4 Read the sentence from the section "This Has Happened Before."

As a result, mammals from North America invaded South America and

outcompeted many of the native species there for resources.

The word "invaded" connotes something that is:

(A) unusual

(B) unpredictable

(C) undesirable

(D) unbelievable

Answer Key

1 Which sentence from the article BEST supports the idea that scientists have long been

interested in the movement of animals?

(A) In the spring of 2010, a lone gray whale was spotted off the Mediterranean

coast of Israel.

(B) Gray whales are native to the Pacific Ocean.

(C) This was the first North Atlantic sighting of a gray whale in about 200

years.

(D) In recent years, many creatures have been turning up in places they don't

belong.

2 Which paragraph from the section "Scientists Study Faunal Exchange" provides the BEST

evidence that scientists have made forecasts about "faunal exchange"?

Paragraph 7:

The paper presents a list of marine mammals and birds that the authors expect

will move between the Atlantic and Pacific more and more in the future. The list

includes bird species such as Arctic terns, common eiders, Atlantic puffins and

short-tailed shearwaters. Mammals on the list include beluga whales, ringed

seals and Atlantic white-sided dolphins. Altogether, the list contains dozens of

species.

3 Read the sentence from the section "Scientists Study Faunal Exchange."

She said that ideas presented in the paper have been floating around

the scientific community for some time.

What does the phrase "floating around" mean?

(A) moving without any specific direction

(B) being considered but not completely accepted by

(C) moving from one position to another

(D) being considered but not having a purpose

4 Read the sentence from the section "This Has Happened Before."

As a result, mammals from North America invaded South America and

outcompeted many of the native species there for resources.

The word "invaded" connotes something that is:

(A) unusual

(B) unpredictable

(C) undesirable

(D) unbelievable