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Liz Hadly Tracks The Impact Of Climate Change In Yellowstone

8 minutes

(Describer) In an animation, a blue and green lizard with a head like an arrow walks on four legs around a white screen, then freezes. Title: HHMI – BioInteractive.

(Describer) A waterfall gushes at the end of a rocky valley dotted with trees.

(female narrator) Yellowstone National Park.

(Describer) More trees cover a range of hills.

Founded in 1872, it's considered to be the first national park in the world.

(Describer) Sean Carroll:

There's really important lessons from Yellowstone--great lessons. As the first national park, this the place that saved some of the great mammals.

(Describer) Bison graze in a field, and a lake reflects a cloudy sky.

But this vast, carefully managed ecosystem can't protect itself from forces on the outside: global forces of environmental change happening so quickly that their impact is being felt here by both plants and animals.

(Describer) Title: Liz Hadly Tracks the Impact of Climate Change in Yellowstone.

(Describer) Carroll walks with a woman who carries a large backpack.

(narrator) Sean Carroll is visiting Yellowstone with Liz Hadly, who has been studying the biodiversity of Yellowstone for 30 years. They're here to trace the threads that connect the plants and animals living in this park. Their first stop is a grove of whitebark pine trees. This is what a healthy tree looks like--this bark.

(Describer) Hadly:

You can see this is what's given whitebark its name. This is what a healthy tree should look like. The stand that we're in is really in good shape.

(Describer) Some bark curls around bare wood.

(narrator) This particular tree has had a hungry visitor.

(female) These are bear claw marks.

(Describer) Carroll fits his hand into the area.

What's it doing here? Why is it approaching this tree? It's because whitebark pine produce very high-nutrient seeds. The bears'll come here right before they go into hibernation. They really pack on a lot of fat in order to overwinter. The nutrients from those seeds is directly correlated with overwinter survival of bears.

(narrator) But grizzly bears cannot reach most of the pinecones because they're too high up on the trees.

(Describer) A squirrel eats in a tree.

So they rely on a smaller animal for their snack. Red squirrels easily get up to the pinecones to eat the seeds, storing the excess in ground burrows or middens.

(Describer) Carroll and Hadly hike a rocky trail.

(narrator) Down the path, they find evidence that a grizzly bear dug up one of the hiding places. All around us are middens from squirrels. This is what the bears go after.

(Describer) They look down.

Indeed, here is a pile of bear scat.

(Describer) She picks up a brown lump.

In the scat are seeds

(Describer) She pulls it apart.

from whitebark pine.

(Describer) Lighter brown pieces run through it.

So this is most all seed. One hundred percent seeds from whitebark pine. Found what he was looking for. He dug up the midden and there they are.

(Describer) She gives a piece to Carroll.

(narrator) These three organisms, the tree, the squirrel, the bear, represent a healthy food web.

(Describer) A black insect crawls on skin.

But a tiny creature is threatening the survival of all three organisms.

(Describer) At a large tree, Hadly:

(female) Okay, Sean, this tree-- it's been hit by the mountain pine beetle. What you see, the evidence, are these little holes.

(Describer) ...with brown material in them.

What happens when you see this kind of response on the tree, is that the beetles won. This tree is dead. How old is this tree? This tree, probably 700 years or so. How long does it take the beetles to kill a tree like that? Once they attack, it's a day or two. After 700 years? After 700 years.

(Describer) Another tree has bark missing.

(narrator) The beetle has always existed in Yellowstone. It's not a foreign species. What has changed is where and for how long it survives.

(female) The warming climate in this high-elevation region is allowing beetles to move into these, what were previously, high-elevation cold regions. It still gets cold, but not enough to kill the beetle. So they're surviving longer and killing whitebark pine. The warmer Yellowstone's created an opportunity for beetles to the detriment of the whitebark pine. Absolutely.

(Describer) A mountain ridge stands beyond land with small hills and brush.

(narrator) The changing climate is also affecting life lower down the mountain.

(female) There's a pond here. This sometimes holds water earlier in the year. You can see it's almost drying out.

(Describer) Hadly turns.

Look at the dust over where the bison are moving around. That pond no longer stores water. You can see that's dry. Ponds are less permanent. There are fewer ponds that retain water. More ponds never get water. Why is that? We've been getting less rainfall and temperatures have gotten warmer, even just over the last decades. What effects do the drying ponds have on wildlife? The big effect is on the amphibians. We've monitored amphibians for the last 20 years. There are fewer ponds that have amphibians. There are fewer populations of amphibians. There's been a decline in species diversity within ponds having amphibians to begin with, and there are fewer populations for each species in the area.

(Describer) A hand holds a frog. Hadly and Carroll walk on through a field.

(narrator) They visit a pond where aquatic life used to be teeming.

(Describer) They reach the pond.

(female) This is perfect amphibian habitat. See the cover around the margins of the pond. See cover for birds, for salamanders and frogs. I don't hear the frogs. You used to hear the frogs. I don't hear the frogs either. There's an incredible parallel between what's happening with the amphibians and with the whitebark pine.

(narrator) Like the whitebark pine forests high in the mountains, habitats for amphibians here in the valleys are being degraded by climate change.

(Describer) A bison wades across a stream. Carroll:

(male) Yellowstone shows us that it's possible to protect animals, even those pushed to the brink of extinction. We don't want lions and bears and tigers to go the way of the dinosaur. Be gone forever. Something to see in a museum. No idea what they looked or lived like.

(Describer) Light appears in a crack between clouds, and steam rises from a pool.

(female) Yellowstone is a special place.

(Describer) A few trees stand in a field of brush. Hadly:

It's a success story in many ways. But it's not immune to global threats. Climate change, invasive species, population growth-- all these can chip away at the diversity here. Our work is not done.

(Describer) Low sun shines over a ridge.

Funding to purchase and make this educational production

(Describer) Funding to purchase and make this educational program accessible was provided by the U.S. Department of Education. Contact the Department of Education by telephone at 1-800-USA-LEARN, or online at

accessible was provided by the U.S. Department of Education:

PH: 1-800-USA-LEARN (V) or WEB:

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Now Playing As: Captioned (English) (change)

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Elizabeth Hadly has been studying biodiversity in Yellowstone National Park for 30 years. Accompanied by biologist Sean Carroll, she demonstrates different ways in which climate change is impacting the park’s ecosystems. Bark beetles are surviving the winter at higher elevations and killing a large number of white-bark pine trees, disrupting the food web that includes squirrels and grizzly bears. Climate change is also causing ponds to dry up, reducing the pond habitat and decimating the local amphibian population. Although the park provides protected environments for animals, it is not immune from global threats like climate change.

Media Details

Runtime: 8 minutes

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