According to the Denver Museum of Natural History there are eight
different identifiable ecosystems in Colorado. "Explore Colorado"
is an incredible book put out by the museum that would be a great
resource and it is listed in the bibliography. This chapter will
provide a usable definition of an ecosystem and lifezone as well
as a brief overview of all eight ecosystems.
What is an ecosystem? – An ecosystem is a recognizable grouping
of plants, animals, environmental conditions, and the interactions
among them.
What is a lifezone? – A lifezone divides the terrain into different
sections based mainly on elevation. Colorado has seven distinct
lifezones.
How are they different? – A lifezone mainly groups according to
elevation, which was vague and did not always group similar environments
together while an ecosystem looks at the community as a whole and
how everything in that community interacts with everything else.
1. Grassland-
Elevation: below 5,500 ft. (sometimes higher in mountain
valleys)
Precipitation: average of 14 inches per year
Temperature range: It is dry all year however summers
are hot and sunny while winters are cold and windy. It is too
dry to support trees but gets too much precipitation to be a
desert.
Interesting information: Birds are often associated
with trees, however several birds make the grasslands their
home, building their nesting sites on the ground in the grass.
" The pronghorn, another swift grassland species, became
a fast runner to escape an old enemy, the now extinct North
American Cheetah." (Explore Colorado. pg.23)
Usual Flora and Fauna:
blue grama yucca bullsnakes larks
western wheatgrass cactus rattlesnakes eagles
buffalo grass snakeweed jackrabbits hawks
coneflower sage prairie dogs squirrels
2. Semidesert shrubland- cool desert
Elevation: 5,000 to10,000 ft.
Precipitation: approximately 10 inches per year (most
of which is snow)
Temperature range: Hot summers, cold winters
Interesting information: Often dusted with white patches
of alkaline. Many of the birds and animals have adapted to the
small supply of water and need little water to survive.
Usual Flora and Fauna:
sagebrush paintbrush lizards
galleta grass rabbit brush rattlesnakes
saltbush juniper sage grouse
pinon greasewood cottontail
cottontail jackrabbits coyote rodents/mice
3. Pinon-juniper woodland- pygmy forest
Elevation: 5,500 to 9,000 ft.
Precipitation: 10 to 20 inches per year
Temperature range: dry year round with hot summers and
mild winters
Interesting information: Pinons rarely grow over 30
feet and are more cold tolerant than their neighboring junipers.
Junipers are drought resistant and usually are on lower slopes.
Usual Flora and Fauna:
pinon pine bitterbrush kestrel
mountain lion juniper mountain mahogany
jays lizards junegrass
ricegrass bats cottontails
4. Riparian land- Includes edges of streams,
lakes, rivers, ponds, creeks, marshes,
and bogs. A riparian environment always includes an aquatic environment
and is the area dividing an aquatic environment from some other
type of ecosystem. A riparian ecosystem can be found within any
of the other ecosystems. Elevation, precipitation, and temperature
range varies depending on the ecosystem in which the riparian
land is found.
Interesting information: There is dense foliage due
to the water supply. The water and plants attract a large variety
of animals that either wander in and out or some specialty creatures
call this their home. There is a lot of layering of both flora
and fauna in this area.
Usual Flora and Fauna:
cottonwoods cattails frogs
bulrush sedges garter snakes
salamanders parsnips willows
muskrat deer toads
5. Montane shrubland-
Elevation: Usually below 6,000 ft.
Precipitation: approximately 14 inches per year
Temperature range: hot, dry summers; cold, dry winters
Interesting information: Shrubs produce an abundance
of seeds, nuts, and fruits, providing animals harvest opportunities
in the fall. Dense foliage supplies animals with well hidden
homes.
Usual Flora and Fauna:
scrub oak serviceberry warblers
squirrels mountain mahogany skunkbrush
turkeys spotted skunk needle-n-thread
smooth sumac buntings coyote
lupine scarlet gila jays
fox towhees mice deer
6. Montane forest-
Elevation: 5,500 to 9,000 ft.
Precipitation: 25 inches or less (most is snow that
usually melts in a few days)
Temperature range: The summers are usually hot and dry.
The winters usually have quick melting snow.
Interesting information: This ecosystem does not have
to be in a mountainous area. Birds especially enjoy this area.
Ponderosa bark smells like vanilla and sometimes even butterscotch.
The tree must be at least 25 years old to reproduce and they
only produce large quantities of seeds every three to five years.
The seeds only germinate if there is an unusually moist spring.
Usual Flora and Fauna:
ponderosa pine douglas fir chipmunks sparrows
juniper aspens marmots bluebirds
lodgepole pine current bats jays
7. Subalpine forest-
Elevation: 9,000 ft. to treeline
Precipitation: 30 or more inches per year
Temperature range: Dark, humid, and cool even in the
summer with lots of snowfall in the winter.
Interesting information: The cold long winters keep
this ecosystem from being very diverse. Animal adaptations here
include a color change in different seasons. Many animals have
large, spread out feet for snow walking, and several hibernate.
An aspen grove is one large organism connected at the roots
and they are all genetically identical.
Usual Flora and Fauna:
columbine engelman spruce grouse pine
wild rose subalpine fir grosbeaks vole
arnica wood nyph hare elk
martin
8. Treeline- is not really an ecosystem
but this shared boundary or transition between the subalpine and
alpine ecosystems is known as an ecotone. Treeline is obvious
from a distance, and the elevation depends on the amount of air
pressure in a particular area. Krummholz or twisted trees
are found here due to the harsh winds and temperature.
9. Alpine Tundra-
Elevation: treeline and above
Precipitation: it has a large amount of snowfall however
it is constantly being wind blown to the subalpine ecosystem
so it is a very dry harsh environment.
Temperature range: it is cold, windy, and rarely above
60 degrees F. and can reach lows of 40 to 50 degrees below zero.
Interesting information: In May or June you may see
watermelonsnow, formed by blooms of algae in deep persistent
snowfields. Sunshine is intense here with thin air. Be sure
to wear sunscreen.
Usual Flora and Fauna:
forget-me-nots moss capion ptarmigan
mountain dryad alpine avens rosy finch
alpine beauty sandwort weasel
martin pika bighorn sheep
