FUNDING FORTHE DESERT
SPEAKSHAS BEEN PROVIDED BY
ASARCO INC. AN INTEGRATED
PRODUCER OF NON-FERROUS METALS
AND OTHER INDUSTRIAL
MINERALS AND PRODUCTS.
ASARCO INC. ADDING VALUE
TO NATURE'S RESOURCES.
AND HEADQUARTERED
IN TUCSON, ARIZONA,
INTERGROUP HEALTHCARE
CORPORATION IS A MANAGED
HEALTHCARE COMPANY SERVING MORE
THAN A QUARTER MILLION MEMBERS.
AND BY, THE ARIZONA GAME
AND FISH HERITAGE FUND,
ARIZONA'S LOTTERY DOLLARS
WORKING FOR WILDLIFE.
[MUSIC AND NATURE SOUNDS]
NO ONE SEES THE WIND, NOT
REALLY; JUST WHAT IT IT TOUCHES.
A LEAF SHIVERS IN THE
CORNER OF YOUR EYE
AND YOU KNOW THE WIND HAS COME
CLOSE. BUT THE WIND'S INVISIBLE
EVEN WHEN IT'S NOT GENTLE AND
WHOLE BUILDINGS SHIVER
AND THINGS COME LOOSE FROM
THE EARTH AND FLY.
HARD TO BELIEVE THAT THIS
MOODY GHOST IS ALSO
A SYSTEMATIC AND
PATIENT BUILDER.
THE DESERT'S SAND DUNES
ARE MADE WITH A TOUCH
SO GRACEFUL THEY'RE NOT
PILES OF SAND AT ALL.
THEY'RE CREATURES.THEY CREEP,
THEY GROW, THEY'RE NOT THE SAME
TWO DAYS IN A ROW,
LIKE LIVING THINGS.
IT'S REALLY THE WIND OF
COURSE BUT WHAT AN ANIMATOR.
MAYBE IN WALT DISNEY'S
WILDEST VISIONS THE EARTH
CAN CREEP LIKE A VAPOR.
BUT THESE VISIONS
ARE REAL. AND THEY'RE MADE OF
STONE.
THIS IS MATURE DUNE SAND. SAND
IS CONSIDERED
MATURE WHEN IT'S GONE A LONG
WAYS.
WHEN IT'S TRAVELED DOWN A LOT OF
RIVERS AND BLOWN IN
A LOT OF WIND. AND THE WAY THAT
YOU CAN TELL IT'S REAL MATURE IS
BECAUSE IF YOU WERE TO LOOK
AT THIS UNDER A MICROSCOPE,
YOU WOULD SEE
THAT IT'S VERY FINE GRAIN,
VERY WELL ROUNDED, VERY--ON
THE AVERAGE, SMALL GRAINS.
AND ALSO, THAT IT HAD A VERY
HOMOGENEOUS COMPOSITION.
IT'S MOSTLY QUARTZ GRAINS,
OVER NINETY PERCENT QUARTZ.
SOMETIMES SAND GRAINS CAN
ROLL A MILLION MILES
JUST GOING BACK AND
FORTH ON A BEACH
OR UP AND DOWN IN THE WIND OF
A DESERT. AND THAT WILL REALLY
ROUND THE SAND GRAIN AND MAKE
IT OBVIOUSLY VERY MATURE.
THE WIND HAS THE POWER TO
MAKE A SAND GRAIN MATURE
BECAUSE IT CAN BLOW A SAND
GRAIN A HUNDRED MILES AN HOUR,
WHEREAS A STREAM IS NEVER
GOING TO GO THAT FAST.
A RIVER CAN FLOW SEVERAL
MILES AN HOUR, BUT THE WIND
CAN CARRY IT FAST ENOUGH TO
CHIP OFF ALL THOSE CORNERS.
THE SAND OF THIS DESERT
ESSENTIALLY CAME DOWN
THE COLORADO RIVER. AND ALL THE
TRIBUTARIES THAT COME INTO
THE COLORADO ARE
CARRYING SAND,
AND SO IF YOU
WERE TO GO OUT,
IF YOU LIVED SAY IN THE
SOUTHWEST JUST ABOUT
ANYWHERE OR IN UTAH OR IN
ARIZONA OR SOUTHEAST CALIFORNIA,
YOU COULD LOOK AT YOUR
LOCAL MOUNTAIN RANGE,
AND THREE HUNDRED
MILLION YEARS FROM NOW,
THAT'S ALL GOING TO
BE RIGHT DOWN HERE
IN THIS DESERT SOMEWHERE OR
ALONG THE SEA OF CORTEZ.
THE REASON THAT'S
HAPPENING IS BECAUSE
THE COLORADO RIVER IS TAKING
ALL THOSE DRAINAGES
AND ALL THAT SAND'S JUST
GOING DOWN TO THE BEACH.
AND ONCE IT GETS
TO THE BEACH,
THEN IT FORMS--THE
WAVES ROLL IT AROUND ON
THE BEACH FOR A WHILE UNTIL
THE WIND COMES ALONG,
WE GET MOST OF OUR
WEATHER FROM THE WEST,
AND THE WIND COMES IN AND
BLOWS THE SAND OFF THE BEACH
AND THEN ACROSS THE DESERT AND
CAN FORM DUNES LIKE THESE.
TWO OF THE SONORAN
DESERT'S DUNE SYSTEMS
LIE ALONG EITHER SIDE OF THE
LOWER END OF THE COLORADO RIVER:
THE ALGODONES DUNES
AND THE MOHAWK DUNES.
THE DUNES.THE WAY THE
SAND GRAINS MOVE IS IN
A LIGHT WIND, THEY JUST
CREEP ALONG UP THE
BACK SIDE OF A DUNE UNTIL
THEY GET TO THE TOP OF IT,
WHICH IS ON THE
DOWNWIND SIDE,
AND THEN THEY JUST SPILL
DOWN IN SHEETS
DOWN THE STEEP SLOPE
ON THE DOWNWIND SIDE.
THAT'S CALLED
THE SLIP FACE.
THE SAND GRAINS, WHEN
THEY'RE ACTUALLY MOVING
IN A LITTLE BIT STRONGER
WIND, WILL START TO BOUNCE UP
OFF THE GROUND AND BE
CARRIED FOR A SHORT DISTANCE
IN THE WIND BEFORE THEY LAND
BACK ON THE SAND DUNE AGAIN.
AND AFTER THEY'RE CARRIED
FOR A FEW FEET AND LAND AGAIN,
THEY'VE DEVELOPED QUITE A BIT
OF SPEED, AND WHEN THEY HIT,
THEY'LL KNOCK OTHER SAND
GRAINS UP IN THE AIR.
SO, THE SAND GRAINS IN A
LITTLE BIT STRONGER WIND
ARE ACTUALLY HOPPING
UP THE SLOPE,
A PROCESS THAT WE
CALL SALTATION,
OR JUST THE HOPPING
OF THE SAND GRAINS.
AND THEN WHEN THEY
GET TO THE TOP,
THEY CAN FALL DOWN THE OTHER
SIDE. NOW THIS WON'T HAPPEN
IN A VERY SMALL DUNE WHEN
IT'S JUST BEGINNING.
BUT, ONCE A DUNE GETS TO
BE ABOUT FIFTEEN FEET LONG,
IT HAS ENOUGH
LENGTH ON IT TO BE A,
KIND OF HAVE A SHADOW
EFFECT FOR THE WIND.
SO, THE WIND BLOWING ACROSS
IT IS PARTIALLY STOPPED,
AND IT CAUSES THE
SAND GRAINS TO FLOW
IN LITTLE EDDIES ON THE
DOWNWIND SIDE OF THE DUNE
AND STOP THERE AND IT'LL
MAKE THE DUNES START
TO GROW BIGGER AND BIGGER
AND BIGGER AND BIGGER.
BECAUSE THE BIGGER
THE DUNE GETS,
THE MORE IT BLOCKS THE WIND
AND THE MORE SAND IS ADDED.
SO, IT'S THE MORE YOU
GET, THE MORE YOU GET.
IT'S WHAT WE CALL A
POSITIVE FEEDBACK PROCESS,
WHICH IS SIMILAR TO THE IDEA
THAT THE RICH GET RICHER:
THE MORE YOU GET,
THE MORE YOU GET.
AFTER A DUNE GETS A
COUPLE HUNDRED FEET HIGH,
IT CAN'T GROW ANY
HIGHER BECAUSE THE SAND
IS BLOWING SO FAST THAT IT
BLOWS THE TOP OFF THE DUNE.
SO THAT'S CALLED A
NEGATIVE FEEDBACK PROCESS.
IT'S JUST THE OPPOSITE. ONCE
THE DUNE GETS A CERTAIN HEIGHT,
IT HAS A SELF-REGULATING
MECHANISM BY WHICH IT CAN'T
GROW ANY HIGHER BECAUSE OF THE
WIND SPEED THAT IT GENERATES.
SOME OF THESE SAND GRAINS,
IF YOU LOOK AT THEM CLOSELY,
CAN TAKE ON ALMOST A FROSTED
APPEARANCE, SORT OF LIKE
FROSTED GLASS THAT'S BEEN
SANDBLASTED OR SOMETHING.
AND THEY FOR A LONG TIME
THOUGHT THAT THIS WAS BECAUSE OF
JUST THE SAND GRAINS
RUNNING INTO EACH OTHER
AND BOUNCING OFF EACH OTHER
AND MAKING IT FROSTED,
BUT NOW IT'S REALIZED
THAT THAT'S NOT TRUE.
THAT THE FROSTING ON THESE
LITTLE SAND GRAINS IS
A RESULT OF THE DEW ACTUALLY
ETCHING THE GRAIN A LITTLE BIT.
AND WHEN IT DOES THAT, IT
SHOWS YOU THAT SILICA,
WHICH IS WHAT SAND IS
MADE OUT OF, EVEN THOUGH
IT'S A VERY HARD MATERIAL
CAN BE SLOWLY DISSOLVED.
NOW IF YOU DIG DOWN FAR
ENOUGH IN THIS DUNE,
YOU'RE GOING TO COME TO A
PLACE WHERE IT'S DAMP AND
WHERE THERE'S ENOUGH
MOISTURE TO REALLY START
DISSOLVING A LITTLE BIT OF
THE SAND, JUST A TINY BIT.
BUT THAT DISSOLVED SILICA
THEN IS IN THE GROUND WATER,
AND IT WILL MOVE
SLOWLY OUT TO SEA.
AND WHEN IT
GETS TO THE SEA,
A VERY INTERESTING SEQUENCE
OF EVENTS BEGINS TO OCCUR
BECAUSE LITTLE
SEA CREATURES,
THE PLANKTON OF THE SEA,
DIATOMS AND RADIOLARIANS
AND OTHER SEA CREATURES,
WILL BUILD THEIR
LITTLE SHELLS OUT OF
DISSOLVED SILICA.
AND ONCE THEY'VE BUILT
THEIR SHELLS OUT OF THIS
DISSOLVED SILICA, THEN THE
ANIMAL FLOATS ALONG IN THE SEA
AND IT USES VARIOUS COMPOUNDS
AND HAS A METABOLIC PROCESS,
JUST AS HUMANS DO OR
ANY OTHER ANIMAL,
AND ONE OF THE
BYPRODUCTS OF THE PROCESS
OF THIS PLANKTON IS WHAT
WE CALL DIMETHYL SULFIDES,
WHICH IS A COMPOUND
CONTAINING CARBON AND SULFUR.
AND WHEN THEY GIVE OFF
THE DIMETHYL SULFIDES,
THESE LITTLE SEA CREATURES
THAT ARE USING SILICA,
THE SAME STUFF THAT
SAND'S MADE OUT OF,
THEY GIVE OFF THIS MATERIAL
INTO THE ATMOSPHERE,
IT GOES UP INTO THE AIR AND
FORMS SEEDS FOR CLOUDS TO GROW.
SO THE MORE
PLANKTON THERE IS,
THE MORE CLOUDS WILL COVER
THAT IMMEDIATE REGION.
THE MORE CLOUDS THERE ARE, THE
MORE REFLECTIVITY THE EARTH HAS
IN THAT REGION, AND SO
THESUNLIGHT DOESN'T HIT
THE EARTH AS HARD, AND THE
SUNLIGHT BOUNCES OFF THE CLOUDS,
AND THE EARTH
COOLS DOWN THEN BECAUSE
NOT AS MUCH SUN IS
HITTING THE EARTH.
SO WE NOW REALIZE THAT THE
PLANKTON ARE COOLING
THE EARTH TO SOME EXTENT,
POSSIBLY SOME KIND OF
A NEGATIVE FEEDBACK
PROCESS FOR
THE HEATING THAT THE
EARTH CAN UNDERGO.
SO IT MIGHT BE A
SELF-REGULATING THERMOSTAT
FOR THE EARTH THAT
INVOLVES SAND,
OR INVOLVES SILICA
FROM SAND LIKE THIS,
AND ALSO INVOLVES A LIVING
CREATURE. WHEN YOU GET CLOSE
ENOUGH TO SEE ACTUAL GRAINS
OF SAND, YOU'RE ALSO AT A GOOD
DISTANCE FOR WATCHING SOME
TRULY LIVING CREATURES.
INSECTS MAKE HOMES
IN THE WINDY DUNES.
BUT THEN INSECTS DIDN'T GET TO
BE THE MOST NUMEROUS CREATURES
ON EARTH BY DECLINING TO
ADAPT IN THE TOUGHER PLACES.
THE INSECTS IN THE DUNES HAVE TO
ADAPT TO THE DESERT JUST LIKE
ANYTHING IN ANY DESERT AREA. AND
THEY HAVE TO WORRY ABOUT
THE HEAT AND WHAT TO
DO TO AVOID THE HEAT.
SO THEY'RE MOSTLY
ACTIVE DURING THE DAY,
IN THE MORNING AND
IN THE EVENING.
THE FRINGES ON THE TOES OF
THE SAND TREADER CRICKET
ALLOW THEM TO DIG THEIR
DEEP BURROWS INTO THE SAND.
AND THE WAY THAT THEY CAN
DO THIS IS THAT THEY WILL
ACTUALLY DIG WITH THEIR FRONT
LEGS AND THE BACK LEGS HAVE
THESE FRINGES WHICH MAKE THEIR
BACK LEGS LIKE LITTLE BASKETS.
AND THEY'LL THROW THE SAND
OUT OF THE HOLE AS IF THEY'RE
TAKING BASKETS FULL OF SAND
AND THROWING THEM OUT.
THE FRINGES PROBABLY ALSO
HELP THEM WALK ON THE SAND
BECAUSE IT'S LIKE
WEARING SNOW SHOES.
YOU'RE EVENING OUT
YOUR WEIGHT ON THE TOP
AND YOU'RE NOT FALLING
INTO THE SAND.
I'M SURE THEY CAN LOCOMOTE
A LOT BETTER THAT WAY.
THE SAND TREADER SPENDS MOST
OF ITS LIFE UNDERGROUND,
AND ESPECIALLY MAY AND JUNE
WOULD BE HOTTEST TIMES
OF THE YEAR, AND IT'S ALMOST
EXCLUSIVELY UNDERGROUND.
THE EGGS ARE LAID, AND
THEY'RE ROOTED IN THE CHAMBER,
WHICH MAY BE UP
TO TWO FEET IN THE GROUND,
AND THEN AFTER THE RAINS BEGIN
IN THE SUMMERS, THE YOUNG WILL
START COMING OUT AND THEY'LL
BUILD THEIR OWN BURROW.
THE GIANT HAIRY SCORPION, WHICH
IS ALSO FOUND IN THE DUNES,
IT MODIFIES ITS BEHAVIOR THE
SAME WAY OTHER INSECTS WOULD
TO AVOID THE HEAT AND
AVOID BEING DESICCATED.
IT ALSO IS ABLE
TO DIG FAIRLY DEEP
BURROWS IN THE SAND
LIKE THE SAND TREADER,
AND IT'S GOT A NICE ADAPTATION
IN THAT IT HAS EIGHT LEGS
RATHER THAN SIX AND IT
CAN DIG A LITTLE BIT MORE
EFFICIENTLY THAN SAY
A SIX-LEGGED ANIMAL.
BUT, IT DOESN'T HAVE ANY
SORT OF SPECIAL FRINGES
ON ITS TOES THE WAY THAT
THE SAND TREADER DOES.
BUT IT'S A PRETTY GOOD DIGGER
ITSELF AND IT WILL DIG IN,
TAKE A REST,
DIG SOME MORE,
UNTIL IT GETS ITSELF INTO THE
SOIL AND IT'S IN A RELATIVELY
MOIST AND WARMER, RATHER, COOLER
PLACE TO STAY.
ONE OF THE BEETLES THAT'S REALLY
COMMON IS THE PINACATE BEETLE,
AND THERE'S SEVERAL DIFFERENT
SPECIES OF IF THAT OCCUR THERE.
THEY WILL ALSO BE ACTIVE
PRIMARILY IN THE EARLY MORNING
HOURS, AND THEY WOULD EVEN
BE ACTIVE MORE IN THE EVENING.
TO AVOID THEIR PREDATORS,
THEY HAVE A CHEMICAL DEFENSE
WHICH THEY USE,
AND YOU CAN SEE,
SOMETIMES WHEN YOU SEE THEM
WALKING, THEY'LL BE WALKING
WITH THEIR HIND ENDS
STUCK UP IN THE AIR.
AND THIS IS IN PREPARATION
FOR DEALING WITH A PREDATOR.
IT WOULD EXUDE A CHEMICAL
FROM ITS HIND END THAT WOULD
DETER PREDATORS. SOMETIMES THESE
BEETLES MAY EVEN PLAY DEAD.
AND IF A PREDATOR HAS COME
ALONG AND GOTTEN
A GOOD DOSE OF ITS
CHEMICAL DEFENSE,
THE BEETLE MAY STILL PLAY
DEAD TO AVOID BEING ACTIVE
AND NOT MOVING, AND
MOVEMENT OFTEN CUES
PREDATORS TO GO
AFTER SOMETHING.
SO IF IT'S PLAYING DEAD
AND IT ALSO HAS THIS
TERRIBLE CHEMICAL
SCENT TO IT,
MOST PREDATORS ARE GOING
TO LEAVE IT ALONE.
THE ANTS THAT ARE IN
THE DUNES HAVE THE SAME
PROBLEMS THAT ANY
DESERT ANIMAL DOES.
ONE OF THEIR OTHER PROBLEMS
IN ADDITION TO THAT
IS GOING TO
BE THEIR FOOD.
THERE ISN'T A LOT OF VEGETATION
THAT GROWS IN THE DUNES,
AND THEY'RE VERY DEPENDENT
ON THE SEEDS OF THE GRASSES.
SO THEY HAVE TO TIME THEIR
ACTIVITY TO WHEN
THE GRASSES ARE
ACTUALLY IN SEED.
THE ANTS, WHEN THEY'RE
BUILDING THEIR TUNNELS
IN THE DESERT, IN THE DUNES
MIGHT HAVE SOME PROBLEMS
WITH THE SAND
BEING SO LOOSE.
THEIR TUNNELS MIGHT
COLLAPSE AND SUCH LIKE THAT.
I WOULD SUSPECT THAT UNDER THE
TOP LAYERS OF SAND, THE SAND IS
A BIT MORE MOIST AND IT
STICKS TOGETHER BETTER.
THE ROBBER FLY SEEMS TO BE
PRETTY COMMON IN THE DUNE AREA.
AND THESE FLIES
TYPICALLY ARE PREDATORS.
EVEN AS LARVAL FORMS,
THEY'RE PREDATORS.
THEY EAT OTHER
SMALL INSECTS.
THE ROBBER FLY, AS FAR
AS LIVING IN THE DUNES,
HAS NO SPECIAL
ADAPTATIONS, PHYSICALLY,
BUT THESE INSECTS SEEM
TO BE ABLE TO ADAPT
BEHAVIORALLY TO THIS
KIND OF CLIMATE.
FOR MOST INSECTS, LIFE ON THE
DUNES IS GOING TO BE A REAL HARD
TIME. IT'S VERY ARDUOUS BECAUSE
THERE'S VERY LITTLE WATER,
THERE'S VERY LITTLE FOOD,
AND THE FACT THAT THE
INSECTS OCCUR HERE MEANS
THAT THEY ARE INCREDIBLY
ADAPTIVE BEHAVIORALLY
TO BE ABLE TO DEAL WITH
DIFFERENT SORTS
OF ENVIRONMENTS.
FOR THINGS THAT WALK AND CRAWL
IT'S DEFINITELY A CHALLENGE
TO HAVE THE EARTH BENEATH YOUR
FEET SHIFTING ALL THE TIME.
BUT PLANTS CAN'T EVEN STEP
ALONG AND TRY ANOTHER SPOT.
THEY'VE GOT TO GET IT
RIGHT THE FIRST TIME.
ONE OF THE CHARACTERISTICS
THAT ALL OF THE
DUNE PLANTS SHARE IN COMMON
IS THE ABILITY TO SURVIVE
IN THE UNIQUE
ENVIRONMENT OF THE SAND.
THE WIND BLOWS IT
BACK AND FORTH,
BLOWS IT AWAY FROM
THE ROOTS OF PLANTS,
PILES IT UP ON PLANTS,
BURIES PLANTS.
AND THE OTHER
CHARACTERISTIC SAND HAS
IS THAT IT HAS SPACE
BETWEEN THE GRAINS.
AND THAT SPACE ALLOWS
WATER TO INFILTRATE
DEEPLY INTO THE SAND, ALLOWS THE
SAND TO HOLD WATER LIKE A SPONGE
SO THAT IT DOESN'T DRY OUT
AS FAST AS OTHER SOILS DO.
WHAT YOU FIND IS THAT
PLANTS THAT LIVE IN THE SAND
HAVE VERY FAST
GROWING ROOTS.
AS SEEDLINGS, THE
ROOTS GROW DEEP,
STRAIGHT DOWN
VERY RAPIDLY,
MUCH FASTER THAN THEY SEND
ENERGY TO ABOVE GROUND GROWTH.
AS WELL, WHEN THE PLANTS
ON THE DUNES GET
EXCAVATED BY THE WIND, AS SAND
BLOWS AWAY FROM THE ROOTS,
THEY'RE ABLE TO
SURVIVE THAT.
THE ROOTS DEVELOP A
HARDENED SURFACE AND
THEY GET VERY WOODY,
AND THEY'RE ABLE TO
ACTUALLY PERSIST WITH A DEEP
EXCAVATION OF THE ROOTS, WHEREAS
MANY OTHER PLANTS MIGHT NOT
SURVIVE THAT KIND OF EXCAVATION.
ANOTHER FEATURE YOU SEE
IN SOME DUNE PLANTS,
SOME OF THE DUNE ENDEMICS,
IS THAT THEY DEVELOP VERY ERECT
UPRIGHT GROWTH FORM, WHEREAS
THEIR CLOSE RELATIVES IN THE
NON-DUNE HABITAT MIGHT SPREAD
OUT AND BECOME VERY BUSHY.
THE DUNE SPECIES GROWS VERY
RAPIDLY, VERY ERECT, AS A
MECHANISM TO AVOID GETTING
BURIED BY THE MOVING SAND.
SO YOU FIND THAT COMBINATION
OF CHARACTERS IN SOME SPECIES,
THE ABILITY TO WITHSTAND
BEING EXCAVATED BY THE WIND,
AS WELL AS THE ABILITY TO
WITHSTAND BEING BURIED BY THE
BLOWING SAND. WELL, SEVERAL OF
THE PLANTS THAT WE FIND AROUND
HERE THAT ARE RESTRICTED
ALMOST ENTIRELY TO DUNES.
HERE IN THE MOHAWK
DUNES, WHERE WE ARE NOW,
THE COMMON GRASS
WE SEE HERE,
BIG GALLETA GRASS IS,
ALTHOUGH YOU CAN FIND
IT HERE AND THERE IN OTHER
PARTS OF THE DESERT, IT'S BY FAR
MORE DOMINANT HERE IN
THE SAND THAN IT IS ELSEWHERE.
ALSO WE SEE DICORIACANESCENS,
ALSO KNOWN AS BUGWEED,
STEPHANOMERIASCHOTTII, SCHOTT'S
WIRELETTUCE. THE PRIMARY
POPULATIONS ARE FOUND PRIMARILY
IN THE SAND DUNES.
AND AS WE MOVE DOWN INTO
THE HEART OF THE GRAN DESIERTO,
THERE'S A NUMBER OF OTHER
SPECIES THAT WE ADD
TO THE LIST
OF DUNE ENDEMICS,
INCLUDING THINGS LIKE
WIGGINS' CROTON,
A SAND FOOD, WHICH IS A
VERY UNUSUAL ROOT PARASITE.
IT GROWS FROM THE ROOTS OF
OTHER SPECIES OF SHRUBS
IN THE SAND--COMES TO THE
SURFACE FOR TWO OR THREE
WEEKS EVERY YEAR TO
PRODUCE FLOWERS AND THEN
DIES BACK UNDER
THE SAND AGAIN.
THINGS LIKE THE
FLATSEEDED EUPHORBIA,
THE DUNE SUNFLOWER,
HELIANTHUS NIVEUS,
VARIETYTEPHRODES; IT'S ONE OF
THOSE SPECIES THAT HAS
A VERY ERECT RAPID-GROWING
GROWTH FORM TO IT
TO ALLOW IT TO OUTGROW THE SAND
THAT MIGHT OTHERWISE BURY IT.
IN THE YUMA AREA, ON
THE ALGODONES DUNES,
WE ALSO FIND A DUNE
FORM OF CREOSOTEBUSH.
ALL OF THEIR STEMS
ARE VERY ERECT,
GROWING TO A HEIGHT OF TEN
OR TWELVE FEET
IN CONTRAST TO THE
FIVE OR SIX FOOT HIGH
CREOSOTEBUSH IN THE SURROUNDING
DESERT.
THE CLIMATE OUT HERE IN THE
DUNES IS VERY UNPREDICTABLE.
WE CAN HAVE ENTIRE YEARS
GO BY WITH NO RAIN,
OR AS WE HAD THIS YEAR, WE
CAN HAVE ALL OF THE RAIN,
THE ANNUAL ALLOTMENT FOR THE
YEAR, FALL WITHIN ONE MONTH.
SO THE DUNE PLANTS, MANY
OF THEM, HAVE THE ABILITY
TO TAKE ADVANTAGE OF
THE RAIN WHEN IT COMES
AND THE ABILITY TO WAIT MAYBE
FOR YEARS UNTIL THE RAINS COME
AGAIN TO BECOME PHYSIOLOGICALLY
ACTIVE TO REPRODUCE.
TYPICALLY, WE SEE WINTER
RAIN COMING TO THE DUNES
IN THIS PART
OF THE COUNTRY.
BUT THEY CAN ALSO EXPERIENCE
SUMMER RAINS AS WELL.
SO THERE'S SPECIES HERE
THAT CAN GREEN UP
AND FLOWER AT VIRTUALLY
ANY TIME OF YEAR.
A GOOD EXAMPLE OF THAT
IS THE SPANISH NEEDLE.
IT'S A PLANT WHICH THERE'S
AN ENDEMIC DUNE VARIETY.
AND WE CAN FIND THAT PLANT
BLOOMING AT VIRTUALLY
ANY TIME OF THE YEAR IF THERE'S
SUFFICIENT MOISTURE IN THE SAND.
WELL, HERE IN THE YUMA
AREA, THE AVERAGE
ANNUAL RAINFALL IS AROUND FOUR
INCHES EVERY YEAR. ALTHOUGH IT'S
NOT UNCOMMON FOR A WHOLE YEAR
OR MORE TO GO BY WITH NO RAIN.
IT'S ALSO NOT
TERRIBLY UNCOMMON,
MAYBE ONE YEAR OUT
OF TEN OR FIFTEEN,
TO HAVE TWICE THAT MUCH
RAIN FALL IN ANY GIVEN YEAR.
AND TYPICALLY THAT MUCH
RAIN WILL FALL IN A PERIOD
OF ONE OR TWO MONTHS
DURING THE RAINY SEASON.
SO THE EXTREMES ARE
TREMENDOUS FROM YEAR TO
YEAR AS TO HOW MUCH
RAIN MIGHT FALL.
SIMILARLY THE TEMPERATURES
OCCASIONALLY MAY FALL DOWN TO
FREEZING HERE, ALTHOUGH NOT
COMMONLY AND THEN IN THE SUMMER
MAY OFTEN HIT ONE HUNDRED AND
FIFTEEN, ONE HUNDRED AND TWENTY.
IN FACT, THE SAND'S
SURFACE MAY HIT
ONE HUNDRED AND
FIFTY VERY COMMONLY.
SO WE SEE EXTREMES OF MOISTURE,
EXTREMES OF TEMPERATURE.
THE PLANTS AND THE ANIMALS
BOTH HAVE TO BE ABLE
TO TOLERATE SOME PRETTY
DRAMATIC CHANGES
FROM DAY TO DAY AND
FROM YEAR TO YEAR.
THESE DUNES ARE SORT DUNES ARE
SORT OF AN EDGE OF THE DESERT.
THE COMBINATION OF SAND
AND WIND WITH DESERT HEAT
AND DRYNESS MAKE IT NEAR THE
LIMIT FOR LIVING THINGS.
MUCH MORE AND IT WOULDN'T BE
AN OUTPOST FOR EVEN THESE
TOUGH SPECIES. AT THAT POINT THE
DESERT BECOMES TRULY DESERTED.
THE LIMITS OF THE DUNES
COME DOWN TO QUANTITY.
THERE'S NOT ENOUGH GROWING
HERE FOR MAYBE BUFFALO.
BUT THERE'S ENOUGH FOR MORE
THAN THE INSECTS. IN FACT,
THE INSECTS THEMSELVES ARE
PART OF THE MENU FOR REPTILES.
THE DESERT'S HARDY REPTILES
SURVIVE IN THE DUNES, TOO.
MOST OF THE ANIMALS WE SEE
IN THE DUNES ARE ADAPTED BOTH IN
COLOR AND IN BEHAVIOR AND IN
MEANS OF LOCOMOTION.
MOST OF THESE SPECIES OCCUR
IN HABITATS OTHER THAN DUNES,
BUT ON THE DUNES TYPICALLY
HAVE A LIGHTER COLOR,
AND OF COURSE SEVERAL ARE
VIRTUALLY ENDEMIC TO THESE
HABITATS WHERE THEY'VE EVOLVED
UNIQUE METHODS OF LOCOMOTION.
THE SIDEWINDER OF COURSE
IS ABLE TO MOVE ON TWO
CONTACT POINTS OF THE
BODY AT ANY GIVEN TIME,
MOVING IN SORT OF AN
S-SHAPED FASHION,
ADVANCING ONE COIL, POSITIONING
IT ON THE SUBSTRATE,
AND THEN ROLLING
THE SECOND LOOP
AHEAD OF THE FIRST, AND THUS
MOVING VERY EFFICIENTLY
OVER THIS
DIFFICULT TERRAIN.
NOW WHEN THEY ELEVATE
THEIR BODIES OFF THE SAND,
THIS OF COURSE REDUCES THE
OVERHEATING FACTOR FROM CONTACT
WITH THE HOT SUBSTRATE
AND ALLOWS THEM TO BE
ACTIVE FOR GREATER
PERIODS OF TIME.
THE SHOVEL-NOSED SNAKE
HAS A WEDGE-SHAPED HEAD,
A COUNTERSUNK LOWER JAW,
NASAL VALVES WHICH ENABLE
THE NOSTRILS TO BE CLOSED WHEN
THE SNAKE IS MOVING THROUGH THE
SAND AND VERY, VERY SMOOTH
SCALES WHICH REDUCE FRICTION
WHEN THE SNAKE IS MOVING BENEATH
THE SURFACE OF THE SAND.
THAT, COMBINED WITH A VERY
ANGULAR UNDERBELLY WITH
ANGLES ALONG THE EDGES
OF THE VENTRAL SCALES,
ENABLES THE SHOVEL-NOSED
SNAKE TO NEGOTIATE
VERY EFFECTIVELY THROUGH
THIS LOOSE SHIFTING SAND.
AROUND THE WORLD, THERE
ARE A NUMBER OF LIZARDS
WHICH HAVE ADAPTED
TO LIFE IN THE DUNES.
THE FRINGE-TOED LIZARD IN
THE NORTH AMERICAN DESERTS
IS AN EXAMPLE
OF ONE OF THESE.
IT HAS EVOLVED FRINGE-LIKE
SCALES ON ITS TOES,
ITS HIND FEET, WHICH
ENABLE IT TO MOVE ABOUT ON
THE SURFACE OF THE SAND WITHOUT
GETTING MIRED DOWN, SOMETHING
ON THE ORDER OF SNOWSHOES,
ONLY ADAPTED FOR SAND.
THE LIZARD ALSO HAS
A WEDGE-SHAPED HEAD,
VERY MUCH LIKE THE
SHOVEL-NOSED SNAKE,
A COUNTERSUNK LOWER JAW,
WHICH REDUCES FRICTION
WHEN IT DIVES
INTO THE SAND,
AND IT TOO IS SOMETHING
OF A SAND SWIMMER.
THE FRINGE-TOED
LIZARD ALSO HAS
SPECIALIZED SCALES
OVER THE EAR OPENINGS,
WHICH PROTECT THE EARDRUM
FROM DAMAGE FROM SAND,
AND THEY TOO HAVE
CRESCENT-SHAPED NOSTRILS
WHICH HAVE MUSCLES WHICH
ALLOW THEM TO CLOSE
WHEN THE LIZARD GOES
BENEATH THE SURFACE,
THUS AVOIDING
INHALING THE SAND.
THERE ARE OTHER
LIZARDS IN THE DUNES,
MOST OF THEM NOT QUITE
AS WELL ADAPTED FOR THIS
SPECIALIZED HABITAT AS
THE FRINGE-TOED LIZARD.
BUT, AMONG THESE WE WOULD
SEE DESERT IGUANAS,
MOST OFTEN AROUND
THE DUNE'S EDGES
RATHER THAN ON THE
OPEN DUNES THEMSELVES.
OF COURSE THEY'RE ADAPTED TO
LIVING IN AND AROUND CREOSOTE,
UPON WHICH THEY
FEED,
AND THEY ALSO EAT A GOODLY
QUANTITY OF INSECTS
IN ADDITION TO
THAT PLANT FARE.
WE ALSO SEE
WHIPTAIL LIZARDS;
THE SAME SPECIES AS WE
FIND IN OTHER PARTS OF
THE SONORAN DESERT, BUT HERE
AGAIN THE POPULATIONS
ON AND NEAR THE DUNES GENERALLY
ARE MUCH LIGHTER GRAY IN COLOR,
AGAIN, A FACTOR
RENDERING THEM LESS
VISIBLE TO PREDATORS,
AND IN PARTICULAR BIRDS.
THE ADAPTABILITY OF THESE
LIVING THINGS IS AMAZING.
BUT THE HEART OF IT, FOR ME,
IS THE PERSISTENCE. LIFE WILL
TAKE HOLD ALMOST ANYWHERE
AND HANG IN THERE SOMEHOW.
PEOPLE ARE LIKE THAT, TOO, BUT
NOT INCLINED TO SUFFER IN THE
SAND LONG ENOUGH FOR FRINGE
TO GROW AROUND THEIR FEET.
THEY DO COME TO
THE DUNES, THOUGH.
WHAT BRINGS THEM IS THE
SAME THING THAT TAKES PEOPLE
DOWN TO THE DEEPEST WATERS AND
UP TO THE ICIEST MOUNTAINTOPS.
THE MOST UNCONFINED OF ALL THE
SPECIES ON EARTH SEEMS TO NEED
TO KEEP TESTING THIS FREEDOM.
MANAGING THE ALGODONES DUNES
WEST OF YUMA HAS RESULTED IN
TWO EXTREMES SIDE BY SIDE.
ON ONE SIDE OF THE ROAD,
OFF-HIGHWAY VEHICLES
ARE PERMITTED TO
PLAY IN THE SAND.
THE OTHER SIDE IS A
PROTECTED WILDERNESS.
EAST OF YUMA, THE MOHAWK
DUNES ARE HANDLED VERY
DIFFERENTLY BUT THAT'S BECAUSE
HERE THERE'S A MILITARY FACTOR.
THE MOHAWK DUNES ARE PART OF THE
LARGER BARIUM GOLDWATER RANGE ON
THE MARINE CORPS SIDE OF IT,
WHICH IS FROM THE MOHAWKS TO THE
WEST, IS AN INSTRUMENTED AIR TO
AIR TYPE TRAINING REFUGE.
THERE IS NO ORDINANCE
THAT'S DELIVERED TO THE
GROUND OR ANYTHING THAT
WOULD IMPACT ON THE GROUND.
WE HAVE SPECIFIC ROADS
THAT WE'RE NOT ALLOWED
TO LEAVE AS WE
TRANSIT THE AREA.
WE ALSO HAVE A
RESPONSIBILITY TO MANAGE
AND CONTROL VISITOR ACCESS
OUT THERE THROUGH
ISSUING PERMITS AND INSTRUCTIONS
TO THEM AS TO WHICH AREAS
AND WHICH ROADS THEY CAN GO
ON SO THAT THERE AREN'T ANY
ADDITIONAL ROADS BEING MADE
OUT IN THAT AREA THAT WOULD
ALLOW ACCESS TO IT. I THINK THAT
AREA, AS WELL AS ALL THE AREAS
IN THE GOLDWATER RANGE, ENJOY A
MUCH GREATER PROTECTION.
THEY ARE NOT MANAGED
FOR MULTIPLE USES.
THEY ARE STRICTLY FROM
MILITARY USE ONLY.
HOWEVER, THEY ARE- THE
ACCESS IS NOT RESTRICTED.
SO THERE'S NO
GRAZING, NO MINING,
NO OFF-ROAD ACTIVITIES
FROM THAT STANDPOINT,
SO THEY ENJOY A MUCH
HIGHER LEVEL OF PROTECTION.
NEXT TIME YOU
HEAR THE WIND WHISTLIN'
AND A DOOR BANGING SOMEWHERE
AND YOU GET A CHILL
AND THINK OF THINGS
BLOWIN' AWAY.
REMEMBER THE WIND BUILDING
SOMETHING PERFECT
IN THE DESERT, ADDING AND
SUBTRACTING, LIFTING AND
SHIFTING EACH GRAIN OF SAND.
YOU'LL FEEL A LOT BETTER.
[MUSIC]
FUNDING FORTHE DESERT SPEAKS
HAS BEEN PROVIDED
BY ASARCO INC. AN INTEGRATED
PRODUCER OF NON-FERROUS METALS
AND OTHER INDUSTRIAL
MINERALS AND PRODUCTS.
ASARCO INC. ADDING VALUE TO
NATURE'S RESOURCES.
AND HEADQUARTERED
IN TUCSON, ARIZONA,
INTERGROUP HEALTHCARE
CORPORATION IS A MANAGED
HEALTHCARE COMPANY SERVING MORE
THAN A QUARTER MILLION MEMBERS.
AND BY, THE ARIZONA GAME
AND FISH HERITAGE FUND,
ARIZONA'S LOTTERY DOLLARS
WORKING FOR WILDLIFE.