Nova (1974–…): Season 43, Episode 11 - Wild Ways - full transcript
From Yellowstone to the Yukon, to Southern Africa's elephant highways stretching across five nations, explore how newly established wildlife corridors may offer a glimmer of hope to some of our planet's most cherished-but endangered-species.
[announcer] Help everyone explore
new worlds and ideas.
Support your PBS station.
-[growls] -[narrator] Lions...
-[trumpeting] -Elephants...
Bison...
-Wolves. -[all howl]
All over the world, their numbers are plunging.
But why aren't parks like Yellowstone
and wildlife preserves worldwide enough to save
these magnificent creatures?
As big as Yellowstone is,
it's not big enough on its own.
[narrator] These sanctuaries are fast becoming
islands of nature
in a sea of human development.
[Harvey Locke] And the first things to go
are the large mammals.
[narrator] With roads and highways
cutting them in half.
If you chop an ecosystem up, it's immediately in trouble.
[narrator] No longer can elephants migrate
as they have for thousands of years.
[elephants trumpet]
Gone are the vast expanses
lions need to roam and interbreed
to keep their prides healthy.
The females are mating with their cousins,
or their nephews,
even their fathers in some cases.
[narrator] Now, scientists are racing to save them.
[Mike Chase] We know with pinpoint precision
where the elephant is 24/7.
[narrator] Tracking their movements,
understanding their needs.
[Chase] It's a way of them communicating which areas
they need to move
across this vast landscape.
[narrator] Reconnecting parks
and preserves.
To allow our animals to move from one patch
of protected landscape into another.
[narrator] Making the most of
the wilderness that remains.
It's our last chance to protect the diversity
of life on Earth.
[narrator] "Wild Ways", right now on Nova.
[yelping]
[narrator] Tanzania, East Africa,
Serengeti National Park,
home of the greatest wildlife spectacle
left on Earth.
This is the great migration.
Two million wildebeest, zebra and gazelle
follow annual rains
along ancient pathways across Tanzania and Kenya.
Sheltered by national parks and game reserves
covering 12,000 square miles,
some species are still being lost.
[bellows]
Rhinoceros have been hunted out by poachers
for their horns.
Wildebeest and zebra are at risk
because their dry season water supply has been
diverted for human use.
A controversial road and rail project
threatens to sever the ancient
migration route...
And Serengeti is not alone.
All over the world, wild animals are at risk.
In the United States, Yellowstone is one of
our largest national parks.
With nearly 3,500 square miles,
it's bigger than some countries.
Millions come here each year to see its wildlife
and natural wonders.
But this park, like many around the world,
may not be doing its job.
[Stephen Woodley] We have set up
protected area systems
in all parts of the globe.
Most of them are too small
to protect the native biodiversity
that they're set up to protect.
[narrator] So what will it take
to save these animals,
especially when they leave protected areas
to forage for food and find mates?
This places them in danger
because even the best parks have become islands
of nature
surrounded by human development.
To find a solution, biologists are
following animals
along their ancient migration routes.
By understanding their patterns and needs,
scientists hope to come up with a new approach
to save wild species all over the world.
One key question is how much land
wild animals need to survive?
Back in the Serengeti, the African lion
stalks the great migration.
Lions survive by preying on the herds of wildebeest
and zebra.
Biologist Craig Packer has been studying
Serengeti lions for decades.
[Craig Packer] The Serengeti Lion Project
is one of the longest
continuous studies of any animal species on Earth.
We currently keep track of about 24 prides of lions.
That's about 300 individuals,
but since the study began in 1966,
after 50 years we have records of nearly
5,000 individuals.
So this is the female that walked off first.
-The old one. -Yeah. Yeah.
[Packer] She's got these three spots
on the right side.
But it's great having these pictures to go back.
[narrator] Packer knows every lion
in his study area,
-who they mate with, and how many cubs they raise.
-[camera clicks]
It's a unique natural history
going back many generations.
[Packer] Lions live in distinct groups
called prides,
which consist of a stable core of females
that live in the same general area
generation after generation.
[narrator] About a dozen lions live
communally in a pride,
females will even nurse each other's cubs.
Male lions come and go,
mating with females from different prides.
This promotes a healthy exchange of genes.
But if a park is too small and isolated,
this interbreeding can't take place
and the lions will be at risk.
Serengeti, about the size of Connecticut,
is large enough to support 70 lion prides.
Just to the southeast is Ngorongoro Crater,
which is a very different situation.
Ngorongoro features a protected area
in a volcanic crater.
The crater rim encloses a wildlife sanctuary,
but it's surrounded on all sides
by Maasai villages.
-[cows moo] -The Maasai survive
by herding cattle.
To defend their herds, or for prestige,
they will kill lions who would enter or leave
the volcano.
This means the Ngorongoro lions
are isolated
and that leads to inbreeding.
[Packer] So if you have a population
that's as small as the Ngorongoro Crater,
there's only about 30 adults,
and there the females are mating with males
who are their cousins, or their nephews,
or even their fathers in some cases,
and here's where you get a real risk
of inbreeding depression
and inbreeding depression can consist of
cubs that are smaller,
they might not live to their first birthday,
and in some cases they're much more
susceptible to disease.
[narrator] In addition, small populations are
more vulnerable to drought,
famine and over-hunting.
Studying lion populations all over Africa,
Packer has arrived at the minimum
number of lions
needed for a group to survive.
[Packer] Lions, like just about
any other mammalian species,
need to live in a fairly large population
in order to maintain its genetic health
and studies of these situations suggest
that they need to have
at least 1,000 breeding individuals
in the population
to maintain proper levels of genetic diversity.
[narrator] When an isolated population
is wiped out,
and there are no lions close by to resettle
the area,
that species is extirpated,
gone forever from that location.
Once over a million lions roamed and interbred,
from Great Britain to South Africa.
Today there are fewer than 25,000 left,
most living in a handful of
protected areas.
Only four preserves have the 1,000 lions necessary
for long-term survival.
Parks around the world face a similar problem
as human development encroaches.
If you chop an ecosystem up, it's immediately in trouble
and it will lose biodiversity guaranteed.
We know this as much as we know anything
in conservation biology.
[narrator] The loss of biodiversity
can be seen on every continent.
Large predators like lions
have declined by 99%.
Tigers have fewer than 3,000 survivors.
Grizzlies, mountain lions,
and wolves followed a similar drastic decline
in North America,
where bison plummeted from more than 30 million
to a few hundred.
These large mammals are the first to go
when a park is too small and isolated.
In North America, the grizzly bear
is a prime example.
Grizzlies used to inhabit most of Western
North America,
but as human populations grew,
bears were confined
to ever-shrinking pieces of land.
About 40 isolated bear populations
lasted into the 1920s.
Now, outside Alaska, there are only two viable
large groups in the US.
In and around Glacier and Yellowstone National Parks.
Yellowstone is the world's first national park,
founded in 1872.
At that time it was part of a wilderness
that stretched from Mexico to the Canadian Arctic.
But now it's surrounded by ranches, towns
and highways,
and that's a problem for species like
grizzly bears
that need room to roam.
Grizzly bears are true omnivores,
eating everything from berries to meat.
They dig for roots and tubers,
but will also consume fish, greens, or insects.
To make it through their winter hibernation,
they must put on a third of their body weight
in summer and fall.
In their search for food or mates,
it's inevitable that some bears will wander
out of Yellowstone.
This joint works good.
[narrator] Biologist Mike Proctor
wants to understand
the bears' habits
so they can be better protected.
[Proctor] We got a, uh... Canines are in
very good shape. The...
The incisors have medium wear.
They're still pretty good incisors,
so it's not an old bear
and then the third one, the molars are
medium worn,
so we're looking at a six to
eight-year-old male.
[narrator] Proctor darts and tranquilizes
grizzly bears
to monitor their health.
All right... All right I'm going to do
a physical exam,
just see how, any injuries or what shape he's in.
He's got a little wound there.
Why don't you write down, a wound,
it looks like a fight with another male.
Uh, right side of his cheek...
Puncture wound.
When we first get a bear immobilized,
we go in and make sure it's breathing correctly,
and do a round of vitals
we understand its heart rate,
oxygen concentration, its temperature.
We measure its, uh, weight, very important, its age.
We do quite a few other measurements of condition,
we look at parasites and ticks
and body condition in general.
We take blood. We take a DNA sample from their
hair, hand pulled.
Of course it's on a sleeping bear.
The heart rate's 60.
-Good thing I checked, it's fine.
-Oh, okay.
Perfect.
[narrator] Then he attaches a radio collar
that will track
the bear's movements using GPS.
[Proctor] After you put a radio collar
on a grizzly bear,
it collects GPS locations about every hour
for two years.
That collar follows the bear around the landscape
and goes everywhere it goes, every hour
and we find out every specific location
of that bear for a two-year period
and then you put that on 40, or 50, or 60 bears,
and you really start to understand the patterns
of how bears use landscapes, how they move
and how they use habitat and what is important
to them.
This is the, uh,
electronic drop-off time for
two years from now so this bear won't wear
the radio collar for the rest of his life.
They work pretty good. [grunts]
I'm gonna watch the head, pretty clear here.
His nose is twitching. Hey, we're done, we've got
an arm movement, let's go.
[grunts]
Pack up.
[narrator] The radio collar tells an amazingly
detailed life story
of grizzly bears...
Where they find food, make their dens
and choose mates.
After two years with his mother,
a male cub moves out of her territory.
But female cubs will settle nearby.
Males will travel widely, competing with other males
for mating rights to several females.
For example,
Proctor tracked one male,
as he moved several hundred miles
from Canada, across Idaho
and on into Washington
when his collar released.
The challenge is that only 25% of grizzlies
are breeding age females.
If a group becomes too small,
there won't be enough females
and that's the end of the line
for that population.
Proctor decided to use DNA evidence
to pinpoint where that's happening.
Bears have favorite trees they use for a good
back scratch.
Proctor realized he could use the fur
they leave behind
to test the bear's DNA.
Then he developed an even better method
to sample a lot more bears.
You know, I'm wrapping a
kitchen-sized barbwire corral,
which I'm going to fill
with very smelly bait to lure in a grizzly bear.
That grizzly bear is going to come in here
to smell that bait
and leave some hair on this wire.
And with that hair... He didn't even know
he's being sampled... We'll use it
for our, answer to conservationists' questions
using DNA fingerprints.
[narrator] DNA collected from the skin follicles
at the base of each hair, contains the genetic code
unique to each individual
and this can reveal whether different groups of bears
are related and whether they've been interbreeding.
[Proctor] We were looking for places
where grizzly bears were not interbreeding,
for some reason or other,
and we found many of those
places across the landscape.
They all correlated
with major highways and settled valleys.
[narrator] Where highways and human settlements
make it hard
for bears to move around and interbreed,
Proctor discovered that grizzlies
are becoming separated into genetically
different groups.
His DNA records identify 17 populations
from Yellowstone Park to the Arctic Circle.
In the Arctic, bears move freely
and interbreed.
Traveling south toward the US-Canada border,
isolation gets worse.
The 700 bears of Yellowstone are completely cut off,
almost as if they were living
on an island
and scientists now understand
why that is a threat to many species.
In fact, the first clues that parks may be in trouble
came from studying islands.
Starting with Charles Darwin's voyage
to the Galapagos
in the 1830s, a new field of biology developed,
known as island biogeography.
[David Quammen] Island biogeography,
it's a really important
field of study for conservation,
for the prevention of extinctions.
It's the study of where creatures live,
where they don't live and why.
Biogeography.
Island biogeography is that field of study
applied to islands, but, importantly,
also to island-like fragments
of habitat.
[narrator] Islands often are home
to unique species
like the Galapagos iguana
and the giant tortoise.
But islands have very limited resources.
The smaller the island, the fewer species
it can support.
To see how this principle applied to national parks,
which are like islands within the larger continent,
biologist Michael Soule and his students
launched a series of studies.
[keyboard clacking]
They wanted to know how well national parks
were doing
at protecting the species
that were there when the parks were created.
[Michael Soule] After doing this analysis
of what remained
in the national parks in the United States
was completely consistent with the principles
of island biogeography.
The bigger parks retain
almost all of their species,
but only the biggest parks still had grizzly bears,
and wolves and mountain lions.
The smaller the park, the fewer the predators
there were,
and the fewer the species there were overall.
[narrator] These studies became the foundation
for the new field
of conservation biology.
Soule discovered that a small park also has
another challenge for species survival...
The balance between males and females.
[Soule] Small size is bad for creatures genetically
and also demographically.
Because, for example, if there's only five
or six mountain lions
in a park and there's no...
They can't get in, they can't get out,
every few generations all those five or six
will be males
and that's the end of them because they can't
reproduce.
They're all males.
[narrator] No longer allowed in national parks,
hunting has had a huge impact
on animal populations.
[howling]
Considered pests, wolves were completely hunted
out of Yellowstone in the 1920s.
Today, Doug Smith directs the Yellowstone
Wolf Project,
created to bring wolves back into the park.
Smith and the Yellowstone Wolf Project
collar and track the newly returned
wolf packs.
Reintroduced in 1995,
wolves now occupy every part of the park.
They were brought back into Yellowstone
because biologists realized
that without them the entire ecosystem
-was starting to unravel. -[camera clicks]
In 75 years without wolves, Yellowstone's elk population
had surged and was destroying
the important river bottom ecosystems.
Willow plains like this were rare and eaten down.
When I first came to Yellowstone in 1994,
stands like this were down to my knee level,
and every stem was clipped off by an elk.
I mean every stem.
[narrator] Without the willows,
many birds disappeared.
Without willows shading the streams,
water temperatures rose and fish populations
declined.
Beavers declined as well and without
their constant maintenance
of wetlands, erosion grew worse.
But when wolves were reintroduced in 1995
and started hunting elk,
the river bottom willows recovered.
[Smith] This growth in structure
has produced bird habitat.
We're getting birds like willow flycatchers
and Wilson warblers
that we have not had before.
We've had an increase in beavers.
This very willow plain here, I survey it, has,
depending upon the year, four to six beaver colonies
right back through this.
They increased 12-fold after this
willow resurgence.
[wolves howling]
[narrator] Biologists believe the
ecosystem is recovering,
but the question is whether Yellowstone's wolves
can survive
if they can't reach other wolf groups.
[Smith] Wolves are going to have to be connected
to other wolves.
Through time that has been shown to be
the saving grace for a population of animals.
We need that connectivity, we can't just do it
with this island called the Greater
Yellowstone Ecosystem.
[narrator] If animals can't come and go,
the parks we are counting on
to save wildlife are in trouble.
But biologists have a solution.
[Soule] Conservation biologists
have known how to end
the extinction crisis,
to protect thousands of species
in the United States and other parts
of the world,
by simply,
uh, restoring the connections
between the wild places that still persist.
[narrator] It's known as connectivity
conservation.
Linking the last places where wild animals survive
makes the most out of the core habitats that remain.
But which places outside of parks
are the most important to protect?
To find out, scientists like Mike Proctor
follow the animals.
[Proctor] One of our first bears we caught
crossed the highway
about 12 times in one summer exactly in the same spot,
and that taught us there was something
very important happening at that particular site.
The next year when I came back to work,
there was a "for sale" sign right at the spot
where this bear crossed the highway 12 times
and I just went, okay, a light bulb
went off in my head.
Even though I don't have perfect data yet,
I need to sort of act.
This is, uh...
[narrator] Mike Proctor worked with
conservationist Harvey Locke
to find a way to protect the bears' crossing place.
[Locke] Research by Dr. Michael Proctor
with the Trans-border Grizzly Bear Project
showed that this rather sad little parcel of land
over my shoulder
turned out to be the key connector
for the mother lode of grizzly bears
located in the wild Purcell Mountains
in Southern Canada, across this highway,
south into the States
to the recovering population of grizzly bears
in the Cabinet-Yaak area of northern Montana.
[narrator] Protecting this landscape connection
has enabled bears
to move south from Canada's Purcell Mountains
and connect with grizzly populations
in Montana and Idaho,
which are too small to survive over time.
This linkage, called the
Kid Creek Corridor,
is one piece of a much larger vision.
[Locke] When it became clear through conservation biology
that these wonderful national parks
like Yellowstone and Banff, as great as they were,
weren't sufficient unto themselves,
that they needed to be connected
to each other,
we came up with this idea called
the Yellowstone to Yukon Conservation Initiative...
The idea of making a great corridor
up the Rocky Mountains from Yellowstone
all the way into Northern Canada
near the Arctic Circle.
[narrator] Yellowstone to Yukon
is an ambitious plan
to link national parks.
These core areas are safe havens
where animals can find food,
breed and live
without being threatened.
Connecting them would recreate
the large landscape that existed
before humans came.
[Locke] Now we know that
as big as Yellowstone is,
it's not big enough on its own.
Islands in a landscape become islands
of extinction,
and the first things to go are the large mammals.
The large mammals, the ones that are at
the greatest risk
-of disappearing in the 21st century,
-[trumpets]
the big things like elephants,
and bison and grizzly bears,
and lions require us to practice conservation
at an enormous scale.
[narrator] The plan is to create
a 2,000-mile corridor
linking Yellowstone to the wilderness areas
of Central Idaho.
This would connect to Glacier National Park
and to Waterton Park across the US-Canada border
and on to Banff, Canada's premier national park.
Farther north, protected areas
become bigger and wilder,
all the way to the Peel Watershed
in the Yukon Territory.
The point is not to take over private land
along this corridor, but to work with landowners
and managers of public lands like national forests,
so that wildlife can safely move through.
Proctor's bear DNA map has identified the private lands
most critical to landscape connections.
One of these, in British Columbia,
is known as the Duck Lake Corridor.
Typically in our part of the world,
the mountains are in public hands,
and the valley bottoms are in private hands.
This Duck Lake Corridor is a classic example.
[narrator] Grizzly bears live in the mountains,
but they need to cross private lands in the valley
to find mates and forage for food.
Conservationists have purchased some of this land,
but also work with landowners
to find ways to protect animals
passing through.
They encourage farmers to fence in orchards,
since bears will go after berries and other fruit.
They also recommend bear-proof containers
for securing garbage.
Specially designed bins
can help keep bears away
from human settlements and farms,
where they may wind up getting shot.
Clearing the way for bears
can help protect other species, too.
For example,
biologists learned that the Duck Lake area
is critical for the seasonal migration
of northern leopard frogs.
We know that this mosaic
of habitats from farmers field,
to wildlife sanctuary, to pieces of public land,
is the critical corridor
for grizzly bears.
And we also know that if we can protect
the movements of grizzly bears
in these Rocky Mountains
across the landscape,
that we're going to catch something
like the needs of 85% of the other species in the system.
[narrator] Grizzlies are an indicator species,
a way to gauge the health of not just one species,
but an entire ecosystem.
Another major barrier to wildlife
is the four-lane highway.
With several lanes of traffic
and speeding cars and trucks,
these roads can be death traps.
Many animals are not as lucky as this cub.
Millions are killed every year.
Two major highways cut across
Yellowstone to Yukon...
Interstate 90 in Montana and Idaho,
and the Trans-Canada Highway which runs right
through Banff National Park.
[Woodley] Banff is Canada's
iconic national park,
and it's split by major transportation corridors.
And as the traffic volume went up in the Trans-Canada,
it fractured the park into two sections.
And large numbers of elk, and grizzly bears,
and black bears, and coyotes
were getting killed every year,
and it was very dangerous for people.
[narrator] Woodley and other scientists
at Parks Canada helped design
a road that would protect both humans and animals.
Forty-four crossing structures
now allow wildlife to move safely
through Banff National Park.
[Woodley] There's two basic kinds
of crossing structures,
there's the underpasses which are dark tunnels,
and then there's the overpasses.
When you're on top of them,
even though you have a four-lane highway
running underneath you,
it seems like you're in the forest,
trees growing on them.
And it seems like
certain kinds of animals like grizzly bears
and wolves like to use
those kinds of crossing structures.
[narrator] Motion-activated cameras
have documented more than
200,000 wildlife crossings,
and the number of animal deaths
has been reduced.
South of the US-Canada border
is the flathead Indian reservation,
a key crossing point for animals moving between
Glacier National Park
and the Church Wilderness area in Idaho.
But Route 93 runs right through the reservation.
When it came time to repair the highway,
tribal elders insisted on a design
that would be safe for animals and people as well.
Today, 43 crossing structures complete
one of the most
wildlife friendly road projects in the world.
Whisper Camel Means is a wildlife biologist
for the Salish and Kootenai Tribes.
She maintains a network of motion-sensor cameras
to document animals using the crossing points.
[Camel Means] The crossing structures
are being used.
We're pretty impressed about the number of animals
that are using them.
There's this whole new concept of road ecology
where people are actually thinking about
how roads affect the ground
and affect natural resources,
and affect all of us.
[narrator] Unlike the Trans-Canada
Highway
in Banff National Park,
Route 93 runs through ranches and towns.
Local residents had to be convinced
that the crossing structures were worth the expense.
[Camel Means] The cost of building
these crossing structures,
and putting this type of mitigation into
a road project
is less than the cost of
a bunch of people hitting animals,
a bunch of people getting into wrecks,
people losing their lives.
They're not that expensive
when you look at the big picture.
[narrator] This project allows animals
to safely move to and from
the large wilderness areas of Central Idaho.
But between there and Yellowstone in Wyoming,
the area is filled with cattle and sheep ranches.
The Centennial Valley is a piece of the old west,
featuring large ranches
that stretch as far as the eye can see.
Jim Roscoe is a biologist who works with ranchers
to help wildlife safely pass through their land.
[Jim Roscoe] If there's any one thing
that might have
some pretty substantial
impact for animals being able to move,
yet isn't a huge change in somebody's management
or extremely costly, it might be dealing with
wildlife-unfriendly fences.
[narrator] Outdated fencing poses
real obstacles
to animal movement.
It's a woven wire that has all these little squares.
Uh, these things become buried in the ground
and are a significant barrier to anything that's
trying to move through here.
The worst of it is, is that
whether it's a young deer,
young antelope, young elk, young moose,
they have a really difficult time dealing with this.
[narrator] Even fully grown antelope
struggle with these
old sheep fences.
Built for speed, they can't jump very high.
They need a fence design they can duck under.
[Roscoe] These are the kind of fences
that we're looking at
across the landscape of trying to modify,
or replace, or remove where we can,
uh, because there's other
fence designs out there that can be as effective now
and removes this total barrier to wildlife.
The other thing you can do, certainly, is
it's plain and simple,
is that if you've got gates in the fence,
leave the gates open when the livestock
aren't in the pasture.
[narrator] But the most contentious
issue around Yellowstone
is what to do about wolves,
since they were reintroduced here
in the 1990s.
The problem occurs when
wolves wander beyond park boundaries.
[mooing]
Martin Davis is a rancher in Paradise Valley,
just north of Yellowstone Park.
[Martin Davis] I wish wolves weren't here
that I had to worry about.
It's just one more thing we have to worry about.
We have to go to the mountains
and check on those cows
uh, every other day now,
where back in the day before wolves,
we were able to check on them just once a week or so.
When the wolves are bothering the cows a lot,
then we've found our weaning weights are down,
pregnancy rates down,
so it's been quite an adjustment over the last
15 years or so.
[narrator] Some ranchers take
a harder line on wolves.
State laws permit them to shoot wolves on sight.
Hunters are also angry at the spread of wolves,
which they say impacts the elk hunt.
States surrounding Yellowstone have
opened wolf hunting seasons.
Many of the collared wolves scientists track
have been killed when they
leave the protection of the park.
Wild bison are also targeted,
as some ranchers worry
that they might spread disease to cattle.
It's these kinds of issues that have to be resolved
before national parks can be fully connected.
[Quammen] The vision of connecting
Yellowstone to the Yukon,
it's hugely ambitious, it's not impossible.
It'll take a lot of
really patient, pragmatic,
cooperative work on the ground
with all these different people
who live and make their livings
on that landscape between these wild places.
[narrator] In the far north where there
are fewer people and many animals,
some core wildlife areas are gaining ground.
In Canada's northwest territory,
an area the size of Switzerland
has been protected.
Virginia Falls on the Nahanni River
is higher than Niagara.
It is the centerpiece of the newly expanded
Nahanni National Park Reserve.
[Locke] The Nahanni National Park
was all about creating a big northern anchor for
the Yellowstone to Yukon corridor.
This park is three-and-a-half times
bigger than Yellowstone.
That's why we worked so hard to expand
Nahanni National Park Reserve by six times.
It operates at the scale
of an entire wilderness watershed.
It protects a population of about 500 grizzly bears,
ranges of two or three caribou herds,
a big population of Dall sheep.
It's one of the world's biggest national parks,
and one of its most beautiful places.
[narrator] Although far from complete,
Yellowstone to Yukon has become a model
for similar projects worldwide.
Eight countries in Central America
have made initial efforts to protect
the Mesoamerican Biological Corridor,
known as the Path of the Panther.
In Australia, conservationists are working
to connect protected areas
for 2,000 miles along the east coast.
The goal is to preserve the continent's iconic wildlife,
including koalas, cassowaries, and platypus.
In Asia, scientists hope to link parks across
northern India, Bhutan, and Nepal.
This area runs from the world's highest peak
to lowland jungles and will help protect species
like Bengal tigers and snow leopards.
[trumpeting]
Perhaps the most ambitious
project outside North America
is in southern Africa,
where five countries are cooperating
to create the largest network of protected areas
on the continent.
Angola, Botswana, Zambia, Zimbabwe, and Namibia
are working together to reassemble a landscape
of over 150,000 square miles.
It's known as the Kavango Zambezi Transfrontier
Conservation Area
or the KAZA TFCA.
The network will link
36 parks across five nations.
These lands hold a healthy number of great cats...
Lion, cheetah, and leopard, as well as hippo, giraffe,
and a host of antelope species.
At the heart of this region is Botswana,
where Chobe National Park
harbors the only large elephant population
left in the world, numbering about 200,000.
Here, biologist Mike Chase leads a group called
Elephants Without Borders.
[Mike Chase] One of the tools that
the decision makers have had
in delineating the boundaries of KAZA
is to use the ranges of elephants...
How far these elephants are moving
within each of the particular countries,
as well as identifying those critical linkages,
those corridors,
which areas connect the protected areas.
[narrator] To follow the elephants,
Chase has to use
jumbo-size satellite collars.
The process of darting always starts
by us identifying a focal area,
a region where we want to collar elephants in.
And so the particular area that we've identified
is a series of artificial water holes
that elephants tend to concentrate in large numbers
during the peak dry season.
We're looking to collar an elephant between the age
of 20 and 25.
It's these young bulls that have this propensity
to really move vast distances to explore
and reconnoiter new areas.
[narrator] Tranquilizing a three-ton elephant
requires a powerful drug.
The veterinarian handles these darts with care.
A single drop would kill a human.
The darts are shot from a rifle,
and although these bull elephants won't be harmed,
approaching them with a pointed gun can be risky.
It's a tense 15 minutes
before the elephant falls asleep.
The team hopes he won't run too far,
or enter a deep thicket.
Sometimes he just kneels down
and they have to give the sleeping animal a push.
[man] Okay, watch for that foot.
[narrator] Then it's time
to attach the collar.
The satellite unit is at
the middle of the base of the neck.
Okay.
Typically the collars are on an elephant
for a period of two years,
and we get a GPS location
every hour during that period.
We know with pinpoint precision
where the elephant is 24/7.
Okay, we're almost there, Larry,
just tightening these nuts.
[narrator] Since they can't carry
a scale big enough for an elephant,
they take body measurements to estimate weight.
Three meters and four centimeters.
[narrator] This big fellow checks in
at about 5,000 pounds.
Follow his leg in the center.
[narrator] Elephants' ears
are their cooling system.
It's the best place to find a blood vessel
to administer the antidote.
[woman] Antidote's in, guys.
[narrator] It takes about five minutes
for the elephant to wake up.
Meanwhile, the team retreats to a safe distance.
[Chase] Collaring elephants is
really critical to the work
that Elephants Without Borders is doing.
So the collars provide us with vital information
on not only the movements of elephants,
but that the habitats that
these elephants need to survive.
And with this information, we're better able
to conserve elephants.
It's a direct link that I have with these elephants.
It's a way of them communicating with me
which areas they need
to move across this vast landscape.
[narrator] Elephants cover enormous
territories in their search
for food and water.
An average elephant eats about
300 pounds of vegetation a day,
and drinks about 50 gallons of water.
Female, baby, and juvenile elephants
live in breeding herds,
30 to 60 individuals led by a matriarch.
Using her encyclopedic memory,
this grandmother guides her extended family
to seasonal food and water supplies
across hundreds of square miles.
Increasingly, she must also keep track of which areas
are safe from human conflict and poaching.
Bulls live alone or in bachelor groups
until they enter musk,
and start searching for a mate.
[Chase] The information from
collaring nearly
130 elephants throughout
the Kavango Zambezi TFCA,
has really provided new evidence
on the spatial ecology of elephants.
[narrator] Spatial ecology, as it's
called, maps the lands
animals need to live in
and move through to meet their needs.
Chase's collars have helped pinpoint where cattle fences
and human settlements are
cutting off elephants' migration routes.
Since some fences were taken down,
elephants have been tracked traveling from Botswana,
across Namibia to southeastern Angola.
To get the big picture of elephant numbers
and distribution, Chase has to get up into the air.
To make accurate counts, he installs a pair of rods
on each side of the plane to calculate how much ground
they are covering.
Observers record every large mammal they see
between the rods, and take photographs
to confirm their numbers.
[woman on radio] I've got a breeding herd,
eight adult elephants
and five juveniles.
[Chase] In addition to counting
elephants, we will count
sable, roan, eland, giraffe, kudu, hippo.
So when we say we're counting elephants,
we're really recording and observing
a host of other wildlife species.
[narrator] But here, too, human settlements are
an important factor.
[bells clanging]
While much of Africa is sparsely settled,
its human population has doubled in just 40 years.
As more people come to live around parks,
there's less room for animals,
so conflict is inevitable.
[mooing]
[speaking foreign language]
[Chase] He says there are very many elephants.
There are lots and lots of elephants.
[Thomas speaking foreign language]
During the rainy season,
when they've planted their crops,
elephants come in and crop raid,
and it's a bad time of year with conflict.
If the elephant's in their cropland,
they shoot it, and they report it to wildlife.
Wildlife will come, remove the tusks,
and the meat is shared between the villagers.
To avoid human-elephant conflict
and tragic incidences such as this,
you just need to provide elephants with safe access
to the traditional migratory routes which they've been
using for thousands of years.
[narrator] Maintaining these ancient
corridors is critical
for the survival of animals
and the safety of humans.
People and wildlife are often killed
in these conflicts.
[gunshots]
Wildlife patrols try to steer the elephants away
from farmers' crops by shooting firecrackers
called bear bangers.
To limit conflict, the KAZA conservation effort
is developing incentives
so communities can see a benefit
from wildlife.
[Simon Munthali] To ensure and facilitate
ease of movement of wildlife
across the KAZA landscape,
it is important
that we provide incentives
for local communities in particular,
who should now look at wildlife
as some form of an economic asset to themselves.
And once they start benefitting from wildlife,
they are going to accept
wildlife moving across their land,
as well as contribute to protecting it.
[narrator] To encourage local support,
Botswana has developed an ecotourism industry,
which provides jobs and a cash economy.
Other African countries would like to develop
similar programs.
But it depends on maintaining
healthy wildlife populations
and safe corridors to link protected areas.
But just as elephants have begun to use the corridors,
they have encountered a deadly threat.
The ivory trade has spread to southern Africa
and with it, an epidemic of poaching.
In one park in southern Zambia,
Mike Chase counted 281 elephant carcasses,
and only 133 live elephants.
[Munthali] If poaching exists,
wildlife will not move.
Communities can provide land.
Governments can provide men and resources,
but if we don't deal with poaching,
wildlife will not move.
That is the biggest challenge, is poaching.
[narrator] Angola has been
a tragic case.
It used to have the largest elephant
population in Africa,
200,000 individuals.
But more than half, at least 100,000 elephants,
were killed to feed troops and buy arms
during the long Civil War of the 1990s.
But after the war ended,
the elephants began to return.
[Chase] Those elephants
that weren't killed,
we suspect fled
to the safety and security of Botswana.
And when I first started this study in 2001,
we were able to document
the repopulation of elephants,
elephants moving back into
these woodlands of southeast Angola,
which coincided with the end of the Civil War.
[narrator] The return of elephants
to Angola provides
important evidence
that if international efforts to eliminate
the ivory trade succeed,
elephants will use safe corridors to repopulate
their historic lands.
[Chase] The KAZA TFCA is one of
the last great hopes
for elephant conservation in Africa.
You know, if we can't get it right
in this corner of Africa,
the prospect of elephant conservation elsewhere
in Africa seems bleak.
The repopulation of southeast Angola,
you know, from estimating 100 elephants
to 8,000 elephants,
is arguably one of the greatest conservation
success stories in the last 50 years.
And it's in that spirit and that optimism
that I think that KAZA has the ability to be a refuge
and provide a future for elephants in Africa.
[narrator] Elephants and other
wild species,
lions, grizzly bears, and wolves,
all require room to roam.
Our national parks are essential to their survival,
but conservation biology tells us
they are not enough.
The question is, are there ways to connect these parks
so that the wildlife that
makes them so special can be saved?
[Quammen] To recreate connectivity,
to allow our animals to move
from one patch of protected landscape into another,
we have to make some adjustments.
Some of those adjustments involve adjustments
to the landscape, like overpasses,
and some of those adjustments
are psychological,
cultural, social.
We need to find ways in which people can live
with wildlife and wildlife can live
with people.
[Packer] If we as a species, we as
people in Asia, Europe,
North America, agree that we want these species
to continue into the future along with us,
then we have to take that responsibility,
and we have to find real mechanisms
that will provide the resources
in order to assure
their conservation into the future.
[Soule] This era that we're in now
could be a wonderful opportunity
or a tremendous failure for humanity.
It's our last chance to protect the diversity
new worlds and ideas.
Support your PBS station.
-[growls] -[narrator] Lions...
-[trumpeting] -Elephants...
Bison...
-Wolves. -[all howl]
All over the world, their numbers are plunging.
But why aren't parks like Yellowstone
and wildlife preserves worldwide enough to save
these magnificent creatures?
As big as Yellowstone is,
it's not big enough on its own.
[narrator] These sanctuaries are fast becoming
islands of nature
in a sea of human development.
[Harvey Locke] And the first things to go
are the large mammals.
[narrator] With roads and highways
cutting them in half.
If you chop an ecosystem up, it's immediately in trouble.
[narrator] No longer can elephants migrate
as they have for thousands of years.
[elephants trumpet]
Gone are the vast expanses
lions need to roam and interbreed
to keep their prides healthy.
The females are mating with their cousins,
or their nephews,
even their fathers in some cases.
[narrator] Now, scientists are racing to save them.
[Mike Chase] We know with pinpoint precision
where the elephant is 24/7.
[narrator] Tracking their movements,
understanding their needs.
[Chase] It's a way of them communicating which areas
they need to move
across this vast landscape.
[narrator] Reconnecting parks
and preserves.
To allow our animals to move from one patch
of protected landscape into another.
[narrator] Making the most of
the wilderness that remains.
It's our last chance to protect the diversity
of life on Earth.
[narrator] "Wild Ways", right now on Nova.
[yelping]
[narrator] Tanzania, East Africa,
Serengeti National Park,
home of the greatest wildlife spectacle
left on Earth.
This is the great migration.
Two million wildebeest, zebra and gazelle
follow annual rains
along ancient pathways across Tanzania and Kenya.
Sheltered by national parks and game reserves
covering 12,000 square miles,
some species are still being lost.
[bellows]
Rhinoceros have been hunted out by poachers
for their horns.
Wildebeest and zebra are at risk
because their dry season water supply has been
diverted for human use.
A controversial road and rail project
threatens to sever the ancient
migration route...
And Serengeti is not alone.
All over the world, wild animals are at risk.
In the United States, Yellowstone is one of
our largest national parks.
With nearly 3,500 square miles,
it's bigger than some countries.
Millions come here each year to see its wildlife
and natural wonders.
But this park, like many around the world,
may not be doing its job.
[Stephen Woodley] We have set up
protected area systems
in all parts of the globe.
Most of them are too small
to protect the native biodiversity
that they're set up to protect.
[narrator] So what will it take
to save these animals,
especially when they leave protected areas
to forage for food and find mates?
This places them in danger
because even the best parks have become islands
of nature
surrounded by human development.
To find a solution, biologists are
following animals
along their ancient migration routes.
By understanding their patterns and needs,
scientists hope to come up with a new approach
to save wild species all over the world.
One key question is how much land
wild animals need to survive?
Back in the Serengeti, the African lion
stalks the great migration.
Lions survive by preying on the herds of wildebeest
and zebra.
Biologist Craig Packer has been studying
Serengeti lions for decades.
[Craig Packer] The Serengeti Lion Project
is one of the longest
continuous studies of any animal species on Earth.
We currently keep track of about 24 prides of lions.
That's about 300 individuals,
but since the study began in 1966,
after 50 years we have records of nearly
5,000 individuals.
So this is the female that walked off first.
-The old one. -Yeah. Yeah.
[Packer] She's got these three spots
on the right side.
But it's great having these pictures to go back.
[narrator] Packer knows every lion
in his study area,
-who they mate with, and how many cubs they raise.
-[camera clicks]
It's a unique natural history
going back many generations.
[Packer] Lions live in distinct groups
called prides,
which consist of a stable core of females
that live in the same general area
generation after generation.
[narrator] About a dozen lions live
communally in a pride,
females will even nurse each other's cubs.
Male lions come and go,
mating with females from different prides.
This promotes a healthy exchange of genes.
But if a park is too small and isolated,
this interbreeding can't take place
and the lions will be at risk.
Serengeti, about the size of Connecticut,
is large enough to support 70 lion prides.
Just to the southeast is Ngorongoro Crater,
which is a very different situation.
Ngorongoro features a protected area
in a volcanic crater.
The crater rim encloses a wildlife sanctuary,
but it's surrounded on all sides
by Maasai villages.
-[cows moo] -The Maasai survive
by herding cattle.
To defend their herds, or for prestige,
they will kill lions who would enter or leave
the volcano.
This means the Ngorongoro lions
are isolated
and that leads to inbreeding.
[Packer] So if you have a population
that's as small as the Ngorongoro Crater,
there's only about 30 adults,
and there the females are mating with males
who are their cousins, or their nephews,
or even their fathers in some cases,
and here's where you get a real risk
of inbreeding depression
and inbreeding depression can consist of
cubs that are smaller,
they might not live to their first birthday,
and in some cases they're much more
susceptible to disease.
[narrator] In addition, small populations are
more vulnerable to drought,
famine and over-hunting.
Studying lion populations all over Africa,
Packer has arrived at the minimum
number of lions
needed for a group to survive.
[Packer] Lions, like just about
any other mammalian species,
need to live in a fairly large population
in order to maintain its genetic health
and studies of these situations suggest
that they need to have
at least 1,000 breeding individuals
in the population
to maintain proper levels of genetic diversity.
[narrator] When an isolated population
is wiped out,
and there are no lions close by to resettle
the area,
that species is extirpated,
gone forever from that location.
Once over a million lions roamed and interbred,
from Great Britain to South Africa.
Today there are fewer than 25,000 left,
most living in a handful of
protected areas.
Only four preserves have the 1,000 lions necessary
for long-term survival.
Parks around the world face a similar problem
as human development encroaches.
If you chop an ecosystem up, it's immediately in trouble
and it will lose biodiversity guaranteed.
We know this as much as we know anything
in conservation biology.
[narrator] The loss of biodiversity
can be seen on every continent.
Large predators like lions
have declined by 99%.
Tigers have fewer than 3,000 survivors.
Grizzlies, mountain lions,
and wolves followed a similar drastic decline
in North America,
where bison plummeted from more than 30 million
to a few hundred.
These large mammals are the first to go
when a park is too small and isolated.
In North America, the grizzly bear
is a prime example.
Grizzlies used to inhabit most of Western
North America,
but as human populations grew,
bears were confined
to ever-shrinking pieces of land.
About 40 isolated bear populations
lasted into the 1920s.
Now, outside Alaska, there are only two viable
large groups in the US.
In and around Glacier and Yellowstone National Parks.
Yellowstone is the world's first national park,
founded in 1872.
At that time it was part of a wilderness
that stretched from Mexico to the Canadian Arctic.
But now it's surrounded by ranches, towns
and highways,
and that's a problem for species like
grizzly bears
that need room to roam.
Grizzly bears are true omnivores,
eating everything from berries to meat.
They dig for roots and tubers,
but will also consume fish, greens, or insects.
To make it through their winter hibernation,
they must put on a third of their body weight
in summer and fall.
In their search for food or mates,
it's inevitable that some bears will wander
out of Yellowstone.
This joint works good.
[narrator] Biologist Mike Proctor
wants to understand
the bears' habits
so they can be better protected.
[Proctor] We got a, uh... Canines are in
very good shape. The...
The incisors have medium wear.
They're still pretty good incisors,
so it's not an old bear
and then the third one, the molars are
medium worn,
so we're looking at a six to
eight-year-old male.
[narrator] Proctor darts and tranquilizes
grizzly bears
to monitor their health.
All right... All right I'm going to do
a physical exam,
just see how, any injuries or what shape he's in.
He's got a little wound there.
Why don't you write down, a wound,
it looks like a fight with another male.
Uh, right side of his cheek...
Puncture wound.
When we first get a bear immobilized,
we go in and make sure it's breathing correctly,
and do a round of vitals
we understand its heart rate,
oxygen concentration, its temperature.
We measure its, uh, weight, very important, its age.
We do quite a few other measurements of condition,
we look at parasites and ticks
and body condition in general.
We take blood. We take a DNA sample from their
hair, hand pulled.
Of course it's on a sleeping bear.
The heart rate's 60.
-Good thing I checked, it's fine.
-Oh, okay.
Perfect.
[narrator] Then he attaches a radio collar
that will track
the bear's movements using GPS.
[Proctor] After you put a radio collar
on a grizzly bear,
it collects GPS locations about every hour
for two years.
That collar follows the bear around the landscape
and goes everywhere it goes, every hour
and we find out every specific location
of that bear for a two-year period
and then you put that on 40, or 50, or 60 bears,
and you really start to understand the patterns
of how bears use landscapes, how they move
and how they use habitat and what is important
to them.
This is the, uh,
electronic drop-off time for
two years from now so this bear won't wear
the radio collar for the rest of his life.
They work pretty good. [grunts]
I'm gonna watch the head, pretty clear here.
His nose is twitching. Hey, we're done, we've got
an arm movement, let's go.
[grunts]
Pack up.
[narrator] The radio collar tells an amazingly
detailed life story
of grizzly bears...
Where they find food, make their dens
and choose mates.
After two years with his mother,
a male cub moves out of her territory.
But female cubs will settle nearby.
Males will travel widely, competing with other males
for mating rights to several females.
For example,
Proctor tracked one male,
as he moved several hundred miles
from Canada, across Idaho
and on into Washington
when his collar released.
The challenge is that only 25% of grizzlies
are breeding age females.
If a group becomes too small,
there won't be enough females
and that's the end of the line
for that population.
Proctor decided to use DNA evidence
to pinpoint where that's happening.
Bears have favorite trees they use for a good
back scratch.
Proctor realized he could use the fur
they leave behind
to test the bear's DNA.
Then he developed an even better method
to sample a lot more bears.
You know, I'm wrapping a
kitchen-sized barbwire corral,
which I'm going to fill
with very smelly bait to lure in a grizzly bear.
That grizzly bear is going to come in here
to smell that bait
and leave some hair on this wire.
And with that hair... He didn't even know
he's being sampled... We'll use it
for our, answer to conservationists' questions
using DNA fingerprints.
[narrator] DNA collected from the skin follicles
at the base of each hair, contains the genetic code
unique to each individual
and this can reveal whether different groups of bears
are related and whether they've been interbreeding.
[Proctor] We were looking for places
where grizzly bears were not interbreeding,
for some reason or other,
and we found many of those
places across the landscape.
They all correlated
with major highways and settled valleys.
[narrator] Where highways and human settlements
make it hard
for bears to move around and interbreed,
Proctor discovered that grizzlies
are becoming separated into genetically
different groups.
His DNA records identify 17 populations
from Yellowstone Park to the Arctic Circle.
In the Arctic, bears move freely
and interbreed.
Traveling south toward the US-Canada border,
isolation gets worse.
The 700 bears of Yellowstone are completely cut off,
almost as if they were living
on an island
and scientists now understand
why that is a threat to many species.
In fact, the first clues that parks may be in trouble
came from studying islands.
Starting with Charles Darwin's voyage
to the Galapagos
in the 1830s, a new field of biology developed,
known as island biogeography.
[David Quammen] Island biogeography,
it's a really important
field of study for conservation,
for the prevention of extinctions.
It's the study of where creatures live,
where they don't live and why.
Biogeography.
Island biogeography is that field of study
applied to islands, but, importantly,
also to island-like fragments
of habitat.
[narrator] Islands often are home
to unique species
like the Galapagos iguana
and the giant tortoise.
But islands have very limited resources.
The smaller the island, the fewer species
it can support.
To see how this principle applied to national parks,
which are like islands within the larger continent,
biologist Michael Soule and his students
launched a series of studies.
[keyboard clacking]
They wanted to know how well national parks
were doing
at protecting the species
that were there when the parks were created.
[Michael Soule] After doing this analysis
of what remained
in the national parks in the United States
was completely consistent with the principles
of island biogeography.
The bigger parks retain
almost all of their species,
but only the biggest parks still had grizzly bears,
and wolves and mountain lions.
The smaller the park, the fewer the predators
there were,
and the fewer the species there were overall.
[narrator] These studies became the foundation
for the new field
of conservation biology.
Soule discovered that a small park also has
another challenge for species survival...
The balance between males and females.
[Soule] Small size is bad for creatures genetically
and also demographically.
Because, for example, if there's only five
or six mountain lions
in a park and there's no...
They can't get in, they can't get out,
every few generations all those five or six
will be males
and that's the end of them because they can't
reproduce.
They're all males.
[narrator] No longer allowed in national parks,
hunting has had a huge impact
on animal populations.
[howling]
Considered pests, wolves were completely hunted
out of Yellowstone in the 1920s.
Today, Doug Smith directs the Yellowstone
Wolf Project,
created to bring wolves back into the park.
Smith and the Yellowstone Wolf Project
collar and track the newly returned
wolf packs.
Reintroduced in 1995,
wolves now occupy every part of the park.
They were brought back into Yellowstone
because biologists realized
that without them the entire ecosystem
-was starting to unravel. -[camera clicks]
In 75 years without wolves, Yellowstone's elk population
had surged and was destroying
the important river bottom ecosystems.
Willow plains like this were rare and eaten down.
When I first came to Yellowstone in 1994,
stands like this were down to my knee level,
and every stem was clipped off by an elk.
I mean every stem.
[narrator] Without the willows,
many birds disappeared.
Without willows shading the streams,
water temperatures rose and fish populations
declined.
Beavers declined as well and without
their constant maintenance
of wetlands, erosion grew worse.
But when wolves were reintroduced in 1995
and started hunting elk,
the river bottom willows recovered.
[Smith] This growth in structure
has produced bird habitat.
We're getting birds like willow flycatchers
and Wilson warblers
that we have not had before.
We've had an increase in beavers.
This very willow plain here, I survey it, has,
depending upon the year, four to six beaver colonies
right back through this.
They increased 12-fold after this
willow resurgence.
[wolves howling]
[narrator] Biologists believe the
ecosystem is recovering,
but the question is whether Yellowstone's wolves
can survive
if they can't reach other wolf groups.
[Smith] Wolves are going to have to be connected
to other wolves.
Through time that has been shown to be
the saving grace for a population of animals.
We need that connectivity, we can't just do it
with this island called the Greater
Yellowstone Ecosystem.
[narrator] If animals can't come and go,
the parks we are counting on
to save wildlife are in trouble.
But biologists have a solution.
[Soule] Conservation biologists
have known how to end
the extinction crisis,
to protect thousands of species
in the United States and other parts
of the world,
by simply,
uh, restoring the connections
between the wild places that still persist.
[narrator] It's known as connectivity
conservation.
Linking the last places where wild animals survive
makes the most out of the core habitats that remain.
But which places outside of parks
are the most important to protect?
To find out, scientists like Mike Proctor
follow the animals.
[Proctor] One of our first bears we caught
crossed the highway
about 12 times in one summer exactly in the same spot,
and that taught us there was something
very important happening at that particular site.
The next year when I came back to work,
there was a "for sale" sign right at the spot
where this bear crossed the highway 12 times
and I just went, okay, a light bulb
went off in my head.
Even though I don't have perfect data yet,
I need to sort of act.
This is, uh...
[narrator] Mike Proctor worked with
conservationist Harvey Locke
to find a way to protect the bears' crossing place.
[Locke] Research by Dr. Michael Proctor
with the Trans-border Grizzly Bear Project
showed that this rather sad little parcel of land
over my shoulder
turned out to be the key connector
for the mother lode of grizzly bears
located in the wild Purcell Mountains
in Southern Canada, across this highway,
south into the States
to the recovering population of grizzly bears
in the Cabinet-Yaak area of northern Montana.
[narrator] Protecting this landscape connection
has enabled bears
to move south from Canada's Purcell Mountains
and connect with grizzly populations
in Montana and Idaho,
which are too small to survive over time.
This linkage, called the
Kid Creek Corridor,
is one piece of a much larger vision.
[Locke] When it became clear through conservation biology
that these wonderful national parks
like Yellowstone and Banff, as great as they were,
weren't sufficient unto themselves,
that they needed to be connected
to each other,
we came up with this idea called
the Yellowstone to Yukon Conservation Initiative...
The idea of making a great corridor
up the Rocky Mountains from Yellowstone
all the way into Northern Canada
near the Arctic Circle.
[narrator] Yellowstone to Yukon
is an ambitious plan
to link national parks.
These core areas are safe havens
where animals can find food,
breed and live
without being threatened.
Connecting them would recreate
the large landscape that existed
before humans came.
[Locke] Now we know that
as big as Yellowstone is,
it's not big enough on its own.
Islands in a landscape become islands
of extinction,
and the first things to go are the large mammals.
The large mammals, the ones that are at
the greatest risk
-of disappearing in the 21st century,
-[trumpets]
the big things like elephants,
and bison and grizzly bears,
and lions require us to practice conservation
at an enormous scale.
[narrator] The plan is to create
a 2,000-mile corridor
linking Yellowstone to the wilderness areas
of Central Idaho.
This would connect to Glacier National Park
and to Waterton Park across the US-Canada border
and on to Banff, Canada's premier national park.
Farther north, protected areas
become bigger and wilder,
all the way to the Peel Watershed
in the Yukon Territory.
The point is not to take over private land
along this corridor, but to work with landowners
and managers of public lands like national forests,
so that wildlife can safely move through.
Proctor's bear DNA map has identified the private lands
most critical to landscape connections.
One of these, in British Columbia,
is known as the Duck Lake Corridor.
Typically in our part of the world,
the mountains are in public hands,
and the valley bottoms are in private hands.
This Duck Lake Corridor is a classic example.
[narrator] Grizzly bears live in the mountains,
but they need to cross private lands in the valley
to find mates and forage for food.
Conservationists have purchased some of this land,
but also work with landowners
to find ways to protect animals
passing through.
They encourage farmers to fence in orchards,
since bears will go after berries and other fruit.
They also recommend bear-proof containers
for securing garbage.
Specially designed bins
can help keep bears away
from human settlements and farms,
where they may wind up getting shot.
Clearing the way for bears
can help protect other species, too.
For example,
biologists learned that the Duck Lake area
is critical for the seasonal migration
of northern leopard frogs.
We know that this mosaic
of habitats from farmers field,
to wildlife sanctuary, to pieces of public land,
is the critical corridor
for grizzly bears.
And we also know that if we can protect
the movements of grizzly bears
in these Rocky Mountains
across the landscape,
that we're going to catch something
like the needs of 85% of the other species in the system.
[narrator] Grizzlies are an indicator species,
a way to gauge the health of not just one species,
but an entire ecosystem.
Another major barrier to wildlife
is the four-lane highway.
With several lanes of traffic
and speeding cars and trucks,
these roads can be death traps.
Many animals are not as lucky as this cub.
Millions are killed every year.
Two major highways cut across
Yellowstone to Yukon...
Interstate 90 in Montana and Idaho,
and the Trans-Canada Highway which runs right
through Banff National Park.
[Woodley] Banff is Canada's
iconic national park,
and it's split by major transportation corridors.
And as the traffic volume went up in the Trans-Canada,
it fractured the park into two sections.
And large numbers of elk, and grizzly bears,
and black bears, and coyotes
were getting killed every year,
and it was very dangerous for people.
[narrator] Woodley and other scientists
at Parks Canada helped design
a road that would protect both humans and animals.
Forty-four crossing structures
now allow wildlife to move safely
through Banff National Park.
[Woodley] There's two basic kinds
of crossing structures,
there's the underpasses which are dark tunnels,
and then there's the overpasses.
When you're on top of them,
even though you have a four-lane highway
running underneath you,
it seems like you're in the forest,
trees growing on them.
And it seems like
certain kinds of animals like grizzly bears
and wolves like to use
those kinds of crossing structures.
[narrator] Motion-activated cameras
have documented more than
200,000 wildlife crossings,
and the number of animal deaths
has been reduced.
South of the US-Canada border
is the flathead Indian reservation,
a key crossing point for animals moving between
Glacier National Park
and the Church Wilderness area in Idaho.
But Route 93 runs right through the reservation.
When it came time to repair the highway,
tribal elders insisted on a design
that would be safe for animals and people as well.
Today, 43 crossing structures complete
one of the most
wildlife friendly road projects in the world.
Whisper Camel Means is a wildlife biologist
for the Salish and Kootenai Tribes.
She maintains a network of motion-sensor cameras
to document animals using the crossing points.
[Camel Means] The crossing structures
are being used.
We're pretty impressed about the number of animals
that are using them.
There's this whole new concept of road ecology
where people are actually thinking about
how roads affect the ground
and affect natural resources,
and affect all of us.
[narrator] Unlike the Trans-Canada
Highway
in Banff National Park,
Route 93 runs through ranches and towns.
Local residents had to be convinced
that the crossing structures were worth the expense.
[Camel Means] The cost of building
these crossing structures,
and putting this type of mitigation into
a road project
is less than the cost of
a bunch of people hitting animals,
a bunch of people getting into wrecks,
people losing their lives.
They're not that expensive
when you look at the big picture.
[narrator] This project allows animals
to safely move to and from
the large wilderness areas of Central Idaho.
But between there and Yellowstone in Wyoming,
the area is filled with cattle and sheep ranches.
The Centennial Valley is a piece of the old west,
featuring large ranches
that stretch as far as the eye can see.
Jim Roscoe is a biologist who works with ranchers
to help wildlife safely pass through their land.
[Jim Roscoe] If there's any one thing
that might have
some pretty substantial
impact for animals being able to move,
yet isn't a huge change in somebody's management
or extremely costly, it might be dealing with
wildlife-unfriendly fences.
[narrator] Outdated fencing poses
real obstacles
to animal movement.
It's a woven wire that has all these little squares.
Uh, these things become buried in the ground
and are a significant barrier to anything that's
trying to move through here.
The worst of it is, is that
whether it's a young deer,
young antelope, young elk, young moose,
they have a really difficult time dealing with this.
[narrator] Even fully grown antelope
struggle with these
old sheep fences.
Built for speed, they can't jump very high.
They need a fence design they can duck under.
[Roscoe] These are the kind of fences
that we're looking at
across the landscape of trying to modify,
or replace, or remove where we can,
uh, because there's other
fence designs out there that can be as effective now
and removes this total barrier to wildlife.
The other thing you can do, certainly, is
it's plain and simple,
is that if you've got gates in the fence,
leave the gates open when the livestock
aren't in the pasture.
[narrator] But the most contentious
issue around Yellowstone
is what to do about wolves,
since they were reintroduced here
in the 1990s.
The problem occurs when
wolves wander beyond park boundaries.
[mooing]
Martin Davis is a rancher in Paradise Valley,
just north of Yellowstone Park.
[Martin Davis] I wish wolves weren't here
that I had to worry about.
It's just one more thing we have to worry about.
We have to go to the mountains
and check on those cows
uh, every other day now,
where back in the day before wolves,
we were able to check on them just once a week or so.
When the wolves are bothering the cows a lot,
then we've found our weaning weights are down,
pregnancy rates down,
so it's been quite an adjustment over the last
15 years or so.
[narrator] Some ranchers take
a harder line on wolves.
State laws permit them to shoot wolves on sight.
Hunters are also angry at the spread of wolves,
which they say impacts the elk hunt.
States surrounding Yellowstone have
opened wolf hunting seasons.
Many of the collared wolves scientists track
have been killed when they
leave the protection of the park.
Wild bison are also targeted,
as some ranchers worry
that they might spread disease to cattle.
It's these kinds of issues that have to be resolved
before national parks can be fully connected.
[Quammen] The vision of connecting
Yellowstone to the Yukon,
it's hugely ambitious, it's not impossible.
It'll take a lot of
really patient, pragmatic,
cooperative work on the ground
with all these different people
who live and make their livings
on that landscape between these wild places.
[narrator] In the far north where there
are fewer people and many animals,
some core wildlife areas are gaining ground.
In Canada's northwest territory,
an area the size of Switzerland
has been protected.
Virginia Falls on the Nahanni River
is higher than Niagara.
It is the centerpiece of the newly expanded
Nahanni National Park Reserve.
[Locke] The Nahanni National Park
was all about creating a big northern anchor for
the Yellowstone to Yukon corridor.
This park is three-and-a-half times
bigger than Yellowstone.
That's why we worked so hard to expand
Nahanni National Park Reserve by six times.
It operates at the scale
of an entire wilderness watershed.
It protects a population of about 500 grizzly bears,
ranges of two or three caribou herds,
a big population of Dall sheep.
It's one of the world's biggest national parks,
and one of its most beautiful places.
[narrator] Although far from complete,
Yellowstone to Yukon has become a model
for similar projects worldwide.
Eight countries in Central America
have made initial efforts to protect
the Mesoamerican Biological Corridor,
known as the Path of the Panther.
In Australia, conservationists are working
to connect protected areas
for 2,000 miles along the east coast.
The goal is to preserve the continent's iconic wildlife,
including koalas, cassowaries, and platypus.
In Asia, scientists hope to link parks across
northern India, Bhutan, and Nepal.
This area runs from the world's highest peak
to lowland jungles and will help protect species
like Bengal tigers and snow leopards.
[trumpeting]
Perhaps the most ambitious
project outside North America
is in southern Africa,
where five countries are cooperating
to create the largest network of protected areas
on the continent.
Angola, Botswana, Zambia, Zimbabwe, and Namibia
are working together to reassemble a landscape
of over 150,000 square miles.
It's known as the Kavango Zambezi Transfrontier
Conservation Area
or the KAZA TFCA.
The network will link
36 parks across five nations.
These lands hold a healthy number of great cats...
Lion, cheetah, and leopard, as well as hippo, giraffe,
and a host of antelope species.
At the heart of this region is Botswana,
where Chobe National Park
harbors the only large elephant population
left in the world, numbering about 200,000.
Here, biologist Mike Chase leads a group called
Elephants Without Borders.
[Mike Chase] One of the tools that
the decision makers have had
in delineating the boundaries of KAZA
is to use the ranges of elephants...
How far these elephants are moving
within each of the particular countries,
as well as identifying those critical linkages,
those corridors,
which areas connect the protected areas.
[narrator] To follow the elephants,
Chase has to use
jumbo-size satellite collars.
The process of darting always starts
by us identifying a focal area,
a region where we want to collar elephants in.
And so the particular area that we've identified
is a series of artificial water holes
that elephants tend to concentrate in large numbers
during the peak dry season.
We're looking to collar an elephant between the age
of 20 and 25.
It's these young bulls that have this propensity
to really move vast distances to explore
and reconnoiter new areas.
[narrator] Tranquilizing a three-ton elephant
requires a powerful drug.
The veterinarian handles these darts with care.
A single drop would kill a human.
The darts are shot from a rifle,
and although these bull elephants won't be harmed,
approaching them with a pointed gun can be risky.
It's a tense 15 minutes
before the elephant falls asleep.
The team hopes he won't run too far,
or enter a deep thicket.
Sometimes he just kneels down
and they have to give the sleeping animal a push.
[man] Okay, watch for that foot.
[narrator] Then it's time
to attach the collar.
The satellite unit is at
the middle of the base of the neck.
Okay.
Typically the collars are on an elephant
for a period of two years,
and we get a GPS location
every hour during that period.
We know with pinpoint precision
where the elephant is 24/7.
Okay, we're almost there, Larry,
just tightening these nuts.
[narrator] Since they can't carry
a scale big enough for an elephant,
they take body measurements to estimate weight.
Three meters and four centimeters.
[narrator] This big fellow checks in
at about 5,000 pounds.
Follow his leg in the center.
[narrator] Elephants' ears
are their cooling system.
It's the best place to find a blood vessel
to administer the antidote.
[woman] Antidote's in, guys.
[narrator] It takes about five minutes
for the elephant to wake up.
Meanwhile, the team retreats to a safe distance.
[Chase] Collaring elephants is
really critical to the work
that Elephants Without Borders is doing.
So the collars provide us with vital information
on not only the movements of elephants,
but that the habitats that
these elephants need to survive.
And with this information, we're better able
to conserve elephants.
It's a direct link that I have with these elephants.
It's a way of them communicating with me
which areas they need
to move across this vast landscape.
[narrator] Elephants cover enormous
territories in their search
for food and water.
An average elephant eats about
300 pounds of vegetation a day,
and drinks about 50 gallons of water.
Female, baby, and juvenile elephants
live in breeding herds,
30 to 60 individuals led by a matriarch.
Using her encyclopedic memory,
this grandmother guides her extended family
to seasonal food and water supplies
across hundreds of square miles.
Increasingly, she must also keep track of which areas
are safe from human conflict and poaching.
Bulls live alone or in bachelor groups
until they enter musk,
and start searching for a mate.
[Chase] The information from
collaring nearly
130 elephants throughout
the Kavango Zambezi TFCA,
has really provided new evidence
on the spatial ecology of elephants.
[narrator] Spatial ecology, as it's
called, maps the lands
animals need to live in
and move through to meet their needs.
Chase's collars have helped pinpoint where cattle fences
and human settlements are
cutting off elephants' migration routes.
Since some fences were taken down,
elephants have been tracked traveling from Botswana,
across Namibia to southeastern Angola.
To get the big picture of elephant numbers
and distribution, Chase has to get up into the air.
To make accurate counts, he installs a pair of rods
on each side of the plane to calculate how much ground
they are covering.
Observers record every large mammal they see
between the rods, and take photographs
to confirm their numbers.
[woman on radio] I've got a breeding herd,
eight adult elephants
and five juveniles.
[Chase] In addition to counting
elephants, we will count
sable, roan, eland, giraffe, kudu, hippo.
So when we say we're counting elephants,
we're really recording and observing
a host of other wildlife species.
[narrator] But here, too, human settlements are
an important factor.
[bells clanging]
While much of Africa is sparsely settled,
its human population has doubled in just 40 years.
As more people come to live around parks,
there's less room for animals,
so conflict is inevitable.
[mooing]
[speaking foreign language]
[Chase] He says there are very many elephants.
There are lots and lots of elephants.
[Thomas speaking foreign language]
During the rainy season,
when they've planted their crops,
elephants come in and crop raid,
and it's a bad time of year with conflict.
If the elephant's in their cropland,
they shoot it, and they report it to wildlife.
Wildlife will come, remove the tusks,
and the meat is shared between the villagers.
To avoid human-elephant conflict
and tragic incidences such as this,
you just need to provide elephants with safe access
to the traditional migratory routes which they've been
using for thousands of years.
[narrator] Maintaining these ancient
corridors is critical
for the survival of animals
and the safety of humans.
People and wildlife are often killed
in these conflicts.
[gunshots]
Wildlife patrols try to steer the elephants away
from farmers' crops by shooting firecrackers
called bear bangers.
To limit conflict, the KAZA conservation effort
is developing incentives
so communities can see a benefit
from wildlife.
[Simon Munthali] To ensure and facilitate
ease of movement of wildlife
across the KAZA landscape,
it is important
that we provide incentives
for local communities in particular,
who should now look at wildlife
as some form of an economic asset to themselves.
And once they start benefitting from wildlife,
they are going to accept
wildlife moving across their land,
as well as contribute to protecting it.
[narrator] To encourage local support,
Botswana has developed an ecotourism industry,
which provides jobs and a cash economy.
Other African countries would like to develop
similar programs.
But it depends on maintaining
healthy wildlife populations
and safe corridors to link protected areas.
But just as elephants have begun to use the corridors,
they have encountered a deadly threat.
The ivory trade has spread to southern Africa
and with it, an epidemic of poaching.
In one park in southern Zambia,
Mike Chase counted 281 elephant carcasses,
and only 133 live elephants.
[Munthali] If poaching exists,
wildlife will not move.
Communities can provide land.
Governments can provide men and resources,
but if we don't deal with poaching,
wildlife will not move.
That is the biggest challenge, is poaching.
[narrator] Angola has been
a tragic case.
It used to have the largest elephant
population in Africa,
200,000 individuals.
But more than half, at least 100,000 elephants,
were killed to feed troops and buy arms
during the long Civil War of the 1990s.
But after the war ended,
the elephants began to return.
[Chase] Those elephants
that weren't killed,
we suspect fled
to the safety and security of Botswana.
And when I first started this study in 2001,
we were able to document
the repopulation of elephants,
elephants moving back into
these woodlands of southeast Angola,
which coincided with the end of the Civil War.
[narrator] The return of elephants
to Angola provides
important evidence
that if international efforts to eliminate
the ivory trade succeed,
elephants will use safe corridors to repopulate
their historic lands.
[Chase] The KAZA TFCA is one of
the last great hopes
for elephant conservation in Africa.
You know, if we can't get it right
in this corner of Africa,
the prospect of elephant conservation elsewhere
in Africa seems bleak.
The repopulation of southeast Angola,
you know, from estimating 100 elephants
to 8,000 elephants,
is arguably one of the greatest conservation
success stories in the last 50 years.
And it's in that spirit and that optimism
that I think that KAZA has the ability to be a refuge
and provide a future for elephants in Africa.
[narrator] Elephants and other
wild species,
lions, grizzly bears, and wolves,
all require room to roam.
Our national parks are essential to their survival,
but conservation biology tells us
they are not enough.
The question is, are there ways to connect these parks
so that the wildlife that
makes them so special can be saved?
[Quammen] To recreate connectivity,
to allow our animals to move
from one patch of protected landscape into another,
we have to make some adjustments.
Some of those adjustments involve adjustments
to the landscape, like overpasses,
and some of those adjustments
are psychological,
cultural, social.
We need to find ways in which people can live
with wildlife and wildlife can live
with people.
[Packer] If we as a species, we as
people in Asia, Europe,
North America, agree that we want these species
to continue into the future along with us,
then we have to take that responsibility,
and we have to find real mechanisms
that will provide the resources
in order to assure
their conservation into the future.
[Soule] This era that we're in now
could be a wonderful opportunity
or a tremendous failure for humanity.
It's our last chance to protect the diversity