Download Nevada`s Bioregions

Nevada’s Bioregions
Objectives
• Define was a bioregion is and compare it to an
ecosystem and a biome.
• Identify and describe the unique bioregions of
the state of Nevada.
• Give examples of the characteristic plants and
animals found in each Nevada bioregion.
What is a Bioregion?
• Bioregion: an area constituting a
natural ecological community with
characteristic flora, fauna, and
environmental conditions and
bounded by natural rather than
artificial borders.
– One bioregion is distinguishable
from another by its plants,
animals, water, climate, soils
and land-forms.
What is a Bioregion?
•
•
What it is:
– an area distinguished by its natural
biotic and abiotic features.
– boundaries are more closely related
to the unique communities of plants
and animals found there than they
are to the overall climate.
What it is not:
– Not a biome. Several bioregions
may exist within a simgle biome.
• Area is much smaller than a
biome
– Not an ecosystem. Several
ecosystems may exist within a single
bioregion.
• Area is larger than a single
ecosystem.
Nevada's Bioregions
• Geography:
– Basin and Range Province:
A land of Extremes
• Area is characterized by a
series of Northeast trending
mountain ranges with broad
valleys in between.
• Ranges force precipitation
out of the prevailing
Westerlies as air rises to
move over the crest.
• Microclimates on the ranges
are typically wetter and
cooler than the valleys.
Nevada’s Bioregions
Nevada’s Bioregions
Average January Temperatures
Average July Temperatures
Basin and Range Province
The Basin and Range province has
extremes of altitude change in a
short distance.
Climate conditions vary with
altitude and affect the plants and
animals that are found there.
Each 1000 ft of altitude gain
causes a 3.5 degree F decrease in
average temperature.
Lowest altitudes tend to be the
driest. Tallest peaks may have
snow year-round (alpine tundra
conditions).
Mojave Desert Bioregion
• Southern Nevada:
– Mojave Desert Bioregion:
– Hot, dry desert with high summer
temperatures and warm mild
winters.
– Dominate plant species are
adapted to survive extreme heat
and drought conditions;
• Joshua tree
– Largest member of the yucca
family
• Mojave Yucca
– AKA Spanish bayonet
– Native people used fibers and
seeds
– Home to the yucca night lizard,
a relative of geckos
Mojave Desert Bioregion
• Southern Nevada:
• Creosote bush
– Poisons soil in its root zone
– Will drop it’s leaves to conserve
water in extreme drought
– Spreads by seeds and clones
– Could be the oldest living
organism on earth (unconfirmed)
• Cholla
– AKA Jumping Cholla, Teddy Bear
Cholla
– Several different species are
present in this bioregion
– Grows in large “forests” that can
cover acres of land
– Spreads by seeds and sprouting
from broken pieces carried by
animals, wind, or water
Mojave Desert Bioregion
• Southern Nevada:
– Dominate animal species include:
– Reptiles:
• Collared Lizard
– Large carnivorous lizard
– Eats insects, small rodents, and other
lizards
• Chuckwalla
– Largest lizard of this bioregion (18 to 24
inches)
– Is a herbivore that eats fruit, flowers,
and vegetation
– Wedges itself in rock outcrops for
protection
• Desert iguana
– Another vegetarian that eats flowers
– Prefers sandy habitat because it lives in
burrows
Mojave Desert Bioregion
• Southern Nevada:
– Reptiles:
• Sidewinder
– AKA Horned Rattler
– One of three members of the
rattlesnake family in this bioregion
– Adapted to movement over loose, sandy
soil
• Whiptail
– Members of this species can change sex
in a single-sex population
• Zebra Tailed Lizard
– One of the few reptiles active mid-day
– Curls its tail up over its back when it
runs to confuse predators
– Could be Nevada's fastest lizard
• Desert Tortoise
– Nevada state reptile
– Another herbivore that eats flowers
– Can live 80 to 100 years
Mojave Desert Bioregion
• Southern Nevada:
– Rodents:
• Kangaroo Rat
– Can survive without ever drinking water
– Extracts water from the metabolism of
carbohydrates in the seeds it eats
• Pack Rat
– Builds a midden of collected items
which it may “pack” from place to place
– Attracted to light colored, shiny objects
– Climate change has brought about
adaptations to be able to eat toxic
Creosote Bush
• Jack Rabbit
– Not a rabbit, but a hare
– Named by prospectors after the
burrows they used as pack animals
• Common Field Mouse
– Most widely distributed rodent in North
America
Mojave Desert Bioregion
Southern Nevada:
– Birds:
• Raven
– Large intelligent bird that lives in
cooperative groups
– Will hunt or scavenge to survive
• Cactus Wren
– Common bird of Joshua forests
– Eats seeds and insects
• Burrowing Owl
– Night flying carnivore that eats
small rodents
– Spends daylight hours in a burrow
to escape the heat
• Roadrunner
– Hunts insects, snakes, and lizards
– Often builds nests in the tops of
cholla or other cactus
Mojave Desert Bioregion
• Southern Nevada:
– Larger mammals:
• Coyote
– Prefers meat but will eat just about
anything
– Escapes the heat in an underground
den
• Bobcat
– Hunts rabbits, mice, and pack rats
• Kit Fox
– Competes with coyote and bobcat for
food
– Smaller size gives it an advantage
• Desert Bighorn Sheep
– Nevada state mammal
– Sure footed climber
– Requires stable water sources
End Section I