Types of Grasslands in North America
Learn the types of grasses that form the Great Plains and how these ecosystems relate to upland bird habitat in North America
Most of us become familiar with North America’s plains while reading accounts of Lewis and Clark’s voyage west or Laura Ingalls in Little House on the Prairie. For some, this is where their curiosity about the grasslands stopped. My journey, however, continued well beyond that initial exposure. Growing up in the plains, I was surrounded by true naturalists—folks in tune with the ebbs and flows that the seasons provide on this landscape. These naturalists, along with my own experience and education, taught me that the very nature of this vegetation dictates where upland bird species can be found within our Great Plains.
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North America’s sea of grass once covered an area from Illinois to Wyoming and Canada to Texas, touching or encompassing around seventeen states. This “Great Plains” grassland ecosystem is most simply divided into three ecotones: tallgrass, mixed grass, and shortgrass. Within these ecotones there are many ecosites, such as the Sandhills of Nebraska or the Flint Hills of Kansas. These ecosites occur on gradients of longitude, precipitation, and soil.
Most recently, the North American Grasslands Conservation Act has been introduced to congress to push towards better grasslands conservation in the United States.
Tallgrass overview and conservation
The tallgrass prairie’s eastern edge starts in Illinois and moves west and north until you reach the eastern border of the Dakotas and cross into Canada. This ecotone receives the most annual rainfall, over 30 inches, resulting in the tallest vegetation of the three zones. The grass here is typically waist- to head-height or taller. Dominant grass species within the prairie include little bluestem, big bluestem, Indiangrass, and switchgrass, all of which you’ve likely encountered while walking Conservation Reserve Program (CRP) land or reseeded state walk-in areas.
Tallgrass systems have been severely fragmented by consistent conversion to row crops and development. Most areas of tallgrass prairie are small, less than 1000 acres, resulting in an ecosystem that’s less than 1% of its historic area. Undesirable species such as smooth brome and Kentucky bluegrass moved in through plantings or poor management and converted many diverse stands of tallgrass to monocultures. This area once held high densities of native upland birds but now is most commonly associated with pheasants, although an encounter with a prairie chicken can still be had.
Mixed grass overview and conservation
The mixed grass ecotone is the largest and most diverse prairie type located throughout the central area of North America, stretching from eastern Montana to Oklahoma. Following an east-to-west rainfall gradient, this ecotone receives approximately 12-30 inches of annual precipitation with typical grass heights dependent on local conditions (generally knee- to waist-high). Grass type, meaning cool- or warm-season species, varies greatly depending on the longitude. The diversity of grass types within the system leads to high biodiversity of game and non-game species.
Habitat threats to mixed grass systems include fragmentation through row cropping and development as well as the encroachment of woody species. Due to the expanse and diversity of the mixed grass prairies, local habitat conditions vary greatly. Bird hatches and suitable hunting cover are unpredictable unless you have local knowledge or have spent time researching and scouting. Throughout the entire mixed grass prairie, you may encounter sharp-tailed grouse, prairie chickens, and pheasants; in the northern region you may trip on a Hungarian partridge, while in the south you’re more likely to flush a covey of bobwhite quail.
Shortgrass overview and conservation
Between the Rockies and mixed grass prairie sits the shortgrass prairie. This ecotone receives the lowest average annual precipitation (15 inches), with more falling in the southern states (20 inches) than in the northern states (12 inches). Common shortgrass species like buffalo grass or gramas don’t generally grow past the tops of your boots; as a result, holding cover for upland birds is minimal.
Primary threats to the shortgrass system include habitat fragmentation from energy development, urban development, and poor grazing practices. If upland bird hunters are to encounter game, it’s likely to be near water or row-cropped agriculture. Rainfall and the timing thereof are especially important in the shortgrass prairie because the system is more susceptible to drought than other grassland ecotones.
Scouting the grasslands
I look for three basic elements when scouting in any of the ecotones of the Great Plains.
- How much habitat is there? Try to find areas in which birds could reasonably complete their lifecycle. Although finding one quarter section of grass in a sea of corn looks appealing (where in the heck else would those birds go?!), the reality is that large tracts of habitat produce a greater number of birds.
- How is the quality of habitat? This will be species-specific, but generally speaking, lots of native plants and signs of past disturbances are good things. Pastures that were grazed earlier (signs of dried manure) or previously burned (scorch marks on fenceposts or standing trees) are enticing because the ground is being actively managed. Grasslands and the birds found within them evolved to coexist with disturbances such as grazing and fire. Thick thatch, or dried grass that is not from the current year’s growth, and encroaching trees or brush are typical signs of declining productivity.
- How diverse is the habitat and geography? Look for areas that are not uniform in height or species; this strategy will decrease the amount of time wasted by walking in introduced, unproductive cover. Look for habitat that has wetlands, uplands, subtle topography changes, agricultural practices, etc. to increase your opportunities for encountering birds.
Resources for hunting grasslands
Basic digital mapping programs (Garmin, OnX, and GoogleEarth) do wonders when planning trips to the plains, especially if you look back several years or decades to determine what the land use trend has been. If the land surrounding the parcel has a history of row crops, call the elevator to see how much corn is out and avoid those areas until after harvest. Coupling grass production forecasts like Grasscast and tracking drought conditions pays dividends when looking at areas that received little rainfall and likely won’t produce favorable holding cover.
I recently started tracking localized events such as hail, fire, and floods that occur from the middle of May until September 1st through a plethora of apps and locations on my smart phone. I avoid hunting areas that received nest- or chick-damaging events.
Lastly, a copy of Grassland Plants of South Dakota and the Northern Great Plains will help you identify the plant species where you encounter game, allowing you to look for similar habitat in other locations. I was fortunate enough to learn plant identification from the author, Dr. Gary Larson, whose knowledge of grassland plants was passed along to most public and private land managers throughout the northern plains.
A note on private lands
Most of the acreage located within the footprint of the Great Plains is private working land utilized for agriculture. Hunters should be respectful of these landscapes and the people that manage them. Knocking on doors can still be a productive endeavor, but be cognizant of sensitive times such as college football on Saturdays (I’m in Cornhusker country) or church on Sundays. Think twice about field dressing birds and always ask a landowner how they would like gates left (closed or as they were). Pay attention to where you park or drive to avoid starting wildfires, leaving ruts, or interrupting working operations. And finally, please support habitat organizations that are working diligently with these private land managers to improve grassland conditions throughout the plains.
