Alberta Parks Home

Natural Heritage


A natural region is a landscape that contains similar landforms, climates, soils, plants and wildlife.  Alberta has six Natural Regions - Boreal Forest, Canadian Shield, Foothills, Grassland, Parkland and Rocky Mountains. Writing-on-Stone / Áísínai'pi is located in the Grassland Natural Region.

Alberta's grasslands are part of the Great Plains stretching from Canada's prairie provinces to the Gulf of Mexico. The grasslands are flat to gently rolling with a few larger hills. Many unique plant and animal species inhabit the grasslands.

Invasive species are one of the greatest threats to natural biodiversity in Alberta's parks. They degrade habitats and endanger native species and plant communities.  Non-native or "alien" plants reduce recreational opportunities and are costly to manage. Preventing and controlling these unwanted plants is important to ensure Writing-on-Stone / Áísínai'pi remains healthy and protected.

Writing-on-Stone / Áísínai'pi protects some of the most diverse natural landscapes and habitats in the mixed grasslands region of North America.

The species here have adapted to a semi-arid climate where water is scarce and rain is unpredictable. Water flowing year-round in the river and creeks makes this an important refuge in the dry plains.

The varied terrain of the Milk River valley creates environmental conditions and microclimates that support four distinct habitats

Each habitat supports a unique animal and plant community.  Some species like mule deer, coyote, prairie rattlesnake and bullsnake are found in all the habitats.


During the Cretaceous Period, Writing-on-Stone / Áísínai'pi lay at the western edge of the Pakowki Sea. Mud, sand and clay were deposited as this inland sea slowly retreated.  Over millions of years, these sediments were buried, compressed and hardened into the sedimentary rocks of the Milk River Formation.

During the Wisconsin glaciation (approximately 70,000 to 10,000 years ago), Writing-on-Stone / Áísínai'pi lay deep beneath the Laurentide ice sheet. The ice sheet began to melt some 20,000 years ago, retreating to the northeast. Large lakes formed along the southern margins of the ice sheet.  These are known as proglacial or ice margin lakes.

The ice acted as a dam, forcing a huge volume of water to drain south from the proglacial lake.  This created deep meltwater channels - the prairie coulees we see today. The meltwater also eroded the ancestral Milk River valley.

Today, the Milk River is the only river in Alberta that flows south into the Mississippi basin.


The range of species found at Writing-on-Stone / Áísínai'pi is greater than most other places on the Alberta prairies. A unique combination of geographical factors contributes to the biodiversity here

A high concentration of Species at Risk in Alberta are protected at Writing-on-Stone / Áísínai'pi.  These include northern leopard frog, ferruginous hawk, loggerhead shrike, Sprague's pipit, long-billed curlew, St. Mary shorthead sculpin, brassy minnow, and western silvery minnow.

Prairie rattlesnakes are found in the park.  Read about the watchable wildlife here.

Please do not pick flowers, grasses or other vegetation.

Writing-on-Stone / Áísínai'pi is home to many beings that have always been important to the Blackfoot.

Other beings that once lived here like makóyi (wolf) and iinííski (bison) may yet return (Blackfoot glossary).


Your experience matters

Help us improve Alberta Parks for all Albertans

Start the Survey Now

Updated: Jul 4, 2017