Park phone lines intermittently out of service
If you cannot reach the park by phone, please click the Contact Us link on the left side of this page to email a ranger. Staff will call or email back during business hours.
The semiarid climate of the Great Plains area has led to the evolution of the grasslands. Agate is a mixed grass prairie, meaning it is a mixture of tall and short grasses growing together. The mixed grass prairie extends from North Dakota through South Dakota, Nebraska, Kansas, central Oklahoma and the north-central part of Texas. Prairies have semiarid climates with high seasonal fluctuation and yearly fluctuations. Most precipitation is received during the growing season; at Agate this is from April to June. Agate averages 15 inches of precipitation a year but during droughts this can be as low as 9 inches or less. Another characteristic of prairies is their flat to rolling terrain and fertile soil rich in organic matter. The climate and soils promote the growth of grasses, not trees which require more water.
Agate displays the rich diversity of the prairie grassland that includes more than just grasses in three distinct areas of the park. The broad floodplain of the Niobrara River has created a riparian area for water-loving plants like cottonwoods, fox tail barley, cattails, reeds, sedges, yellow Siberian irises and blue flag irises. The buttes and hilltops are inhabited by plants that tolerate the drier, rocky conditions such as little blue stem grass, threadleaf sedge, sandhills muley and tufted milk vetch. In between the riparian area and the buttes is the area that most people think of as prairie. This area is inhabited by western, slender, and crested wheat grasses, Blue grama grass, threadleaf sedge and needle and thread grass.
Did You Know?
One of the more menacing beasts found in the quarries at Agate Fossil Beds was the Dinohyus. This big-toothed animal was a scavenger credited with tearing apart the rhino skeletons that ended up in the waterhole bonebed. Although not related to the pig family, his nickname was “Terrible Pig.” More...