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Shortgrass Prairie surrounds nearby Pawnee Buttes

​​​​Shortgrass Prairie surrounds nearby Pawnee Buttes​​ (pictured above)

One hundred miles due east of the Rocky Mountains, North Sterling Reservoir State Park is nestled in the gently rolling prairie grasslands on the western edge of the Great Plains.  The view goes on for miles in every direction, broken only by the bluffs and canyons to the north, with nothing but blue skies above.  The whistling wind and unusual quiet can make the scene seem empty and bleak – until the coyotes begin their evening song, and you notice the chirrk! of alarmed prairie dogs as a red-tailed hawk swoops down for his dinner.

The open prairie may look unremarkable at first glance, but visitors who take the time to look a little closer at the wildlife, plants, and geology of North Sterling State Park will find a hardy ecosystem just as unique and fascinating as any mountain forest.

The Prairie Ecosystem

An ecosystem is a community of living and non-living things that work together to survive and thrive.  Living parts of the prairie ecosystem include familiar animals like coyotes, mule deer, and hawks, as well as plants like cottonwood trees, prickly-pear cactus, and grasses – but don’t forget about the algae and microbes in the water, or the bacteria and insects in the soil.  Non-living, or abiotic, parts of the ecosystem include water, wind, sun, landforms, rocks, pebbles, and the mineral components of the soil. To learn more, play the Prairie Ecosystem Find-A-Word

Every piece of the ecosystem affects the rest in some way.  Most people are familiar with food chains or food webs within an ecosystem – for example, little fish eat algae, plants, and microbes - big fish eat little fish - coyotes and eagles eat big fish.  Each part is just as important as the others.  If something happens to the big fish, then the coyotes and eagles will have to look somewhere else for dinner, and the little fish have a population explosion, because there is nothing to limit their numbers.  The constant interaction between predators and prey maintains a balance between the populations of each species.

But what about the non-living things?  How do they affect the living plants and animals?

The rocks and ground soil affect what kinds of plants can grow here.  Different soils have different mixtures of sand, clay, silt, rocks, and organic matter (from dead plants and animals), which affects how much water and how many nutrients it holds, and how dense or compact it is.  The open landscape – without significant landforms like mountains and foothills to get in the way – results in constant, strong winds that roll across the plains, robbing the air and soil of moisture and blowing bits of sand and soil to new locations.  More than 300 days of sunshine and an average of twelve inches of precipitation per year add their own influence to the mix, forcing plants and animals to adapt or perish.  Vegetation on the open prairie is short and highly water-conservative.  Grasses grow quickly from brief rain and snowmelt in the spring, while tall trees and thick brush only grow where water is abundant.  Animals burrow underground for shelter, and sport colors to match the earth and plants in the background, camouflaged with browns, tans, and yellows to protect themselves in a region with few places to hide.

Do plants and animals affect the rocks, soil, wind, and water?

You’d better believe it! The roots of plants and the underground activities of insects, rodents, and larger mammals like coyotes and prairie dogs help break up and shift around the soil, which redistributes nutrients and improves the soil’s ability to retain water.  Plants are even known to break larger rocks apart as their roots grow and exploit cracks in the stone.  Large plants – like trees – provide windbreaks that shelter smaller plants and animals.  And water?  On-going research following the reintroduction of wolves into Yellowstone National Park more than fifteen years ago includes studies of positive changes in the groundwater levels and the stream hydrology at that park.  Scientists are calling this the trophic cascade – the way that the presence or absence of a top predator like wolves of coyotes can affect every other thing in the ecosystem, including the water table.

In the Wildlife, Plants, and Geology sections, you’ll find out more information about the prairie park you’ll be visiting and the creatures that live here, as well as activities and games you can print out at home and bring with you for some enjoyable family fun!