Grasslands: The Lands and the People That Call Them Home

Before Europeans arrived in North America, grassland prairie ecosystems stretched from Illinois in the east to the Rocky Mountains in the west and from central Canada south into Texas. The exact area is difficult to determine due to discrepancies in what constitutes a grassland and thus is relatively unknown. However, estimates range from 550 million to approximately 1 billion total acres historically, making grasslands the most extensive and continuous ecosystem in North America.

To start things off, it is important to note that not all grasslands are the same. In fact, of the global grassland types, North America has three distinct grassland prairies; shortgrass, mixed-grass, and tallgrass. Determined by their geographic locations and climates, each grassland has its own unique native species (animal and plant) composition. However, all three support large-scale biodiversity and provide crucial ecological and environmental benefits.

Before settlement, it is estimated that tallgrass prairies covered a land area of roughly 150-250 million acres. These vast grasslands spread from Illinois to the eastern edges of present-day North and South Dakota and from southern Manitoba and Saskatchewan into Central Texas. Due to the conversion of this land to suit other uses, it is estimated that somewhere between 1% and 18% of historic tallgrass prairies exist today. These ecosystems are rich with biodiversity, historically consisting of over 500 plant species, nearly all perennial. Tallgrass prairie canopies are typically no taller than 1m, though some species can grow roughly 2m tall, with approximately 85% of the biomass existing belowground. Animal biodiversity in these grasslands is also extensive, consisting of approximately 150 bird species, 30 reptile and amphibian species, and over 30 mammal species.

Mixed-grass prairies are found in the transition zone between tallgrass prairies in the east and shortgrass prairies in the west. These areas are composed of tall and shortgrass prairie species, thus the name "mixed-grass." Before settlement, these grasslands covered an area of approximately 140 million acres, of which 30% or so remain. Mixed-grass prairies stretch from southern Alberta, Saskatchewan, and Manitoba south into Oklahoma and along the Missouri River in what is known as the "Missouri Coteau" region. Plant populations consist of perennial warm- and cool-season grasses, with 3-4 times as many forb species as grass species. The animal species in these ecosystems will be similar to those of the tallgrass prairie, with a few new species introduced along the western and southern ranges (e.g., prairie chickens, burrowing owls, and Texas horned lizards).

Shortgrass prairies make up the western range of the North American grassland prairie. Historically ranging from central Alberta south to Texas and from the Missouri River in the east to central Montana and Wyoming in the west. Shortgrass prairies once accounted for approximately 265 million acres of North American grasslands. Comprised of shortgrass vegetation species, buffalo grass and blue grama account for roughly 70%-90% of shortgrass prairie vegetation weight. Due to the drier climate, roughly 80% of the vegetation found in shortgrass prairie ecosystems exist solely in riparian areas, which constitute 5% of the land area in shortgrass prairies.

Since time immemorial, Native American tribes have called the great plains home. It is estimated that at least thirty Native American tribes, all with distinct languages and cultures, lived throughout the region- it should be noted that this number is an estimate based on the tribes that were encountered by settlers in the 1700s and 1800s and that it is difficult to know all of the Native American tribes that have lived throughout the great plains over time. The lifestyle of many of these tribes was nomadic, which means that they moved campsites throughout the year following food source migrations, primarily that of the buffalo (bison). Despite the nomadic tendencies of the tribes in the area, there were tribes in the region that had agrarian cultures. Examples are the Mandan and Hidatsa tribes that lived along the Missouri River in present-day North Dakota (highlighted in the map to the right). These agricultural practices employed by Native American tribes in the northern plains were small-scale subsistence farms quite dissimilar to today's agricultural practices. They consisted of what would be considered "regenerative agriculture" in today's terms, meaning that the crops stayed in the community and that the organic matter was used to promote soil fertility in the future.

Despite not being agrarian societies, nomadic tribes managed their lands as well, primarily through the use of prescribed burnings. These strategic fires removed dead and/or unwanted vegetation species and promoted desirable growth, including high-value forage to attract grazing animals (bison). These grazing activities would then work to prevent grass species from outcompeting other vegetation, aerate the soil and help mix organic matter into the soil environment. After grazing these areas, the bison would move to new areas, giving the grazed area time to rest and re-grow. These activities occurred across the plains as active management and cooperation between the tribes and the grassland ecosystems. This relationship occurred for hundreds, if not thousands, of years and would have likely continued for longer had the western expansion of the United States happened differently.

The Louisiana Purchase in 1803 brought the lands west of the Mississippi River into the control of the United States of America. This purchase more than doubled the landmass of the US and gave the government the sole right to negotiate land deals with the Native American Tribes across the great plains. This meant that for settlers from the east to move west, the government of the United States would have to enter into treaty agreements with tribal nations for "ownership" of the land. People wanting to move west would then have to buy land from the government within areas ceded by the tribes involved in the treaty- these processes were not always followed by folks wanting to move west (e.g., "boomer sooners" of Oklahoma). The unlawful and "lawful" migration of people west led to decades of violent interactions and skirmishes between settlers and tribes. These mass migrations west not only removed tribal nations from their homelands but also led to the settling and converting of grasslands into towns and croplands. These grassland areas were determined to be prime cropland due to the soil quality of grassland ecosystems.

Between 1850 and 1950, roughly 260 million grassland acres were converted to agricultural fields, and an additional 25-50 million more were lost in the 40 years following (1950-1990), with less than 10% of those acres being converted for purposes other than agriculture. Less than 40% of North America's original grasslands exist today, mostly privately held (both by natives/tribes and non-natives) or as part of the national park system. Currently, the US Forest Service (USFS) manages 20 national grasslands west of the Mississippi (with one tallgrass prairie in Illinois), totaling nearly 4 million acres of natural grassland, 82% of which is found within the great plains region. The largest is the Little Missouri National Grassland in western North Dakota, with over 1 million acres, the smallest being McClean Creek in Texas, with just under 1500 acres.

The largescale decrease in North America's grasslands are due, in part, to the misconception that these grassland areas are devoid of value (resources)- once referred to as the "great American desert." However, it has recently been acknowledged that the loss of grasslands would mean a loss of some of the world's most biologically diverse and environmentally essential ecosystems. Grasslands support thousands of species of vegetation, insects (including pollinators), mammals, reptiles, soil microbes, and bird species- many threatened due to habitat loss. Grasslands also provide significant ecological and environmental benefits. Their soils can support large amounts of vegetation growth, enable water infiltration, and serve to slow water runoff. Additionally, grassland plant species have deep and extensive root systems that retain moisture in the soil (through evaporation reduction) and minimize (if not prevent) soil erosion.

Recent research has found that grasslands are effective carbon sinks, potentially even more so than forest ecosystems. Grasslands hold most of their sequestered atmospheric carbon below ground (60%-80% of all grassland biomass carbon). In contrast, forests store sequestered carbon in the woody material and leaves of trees. By storing carbon below ground, grasslands can hold more atmospheric carbon than forested areas of similar size. Carbon stored in grasslands is also not as available for release back into the atmosphere due to fire and other disturbances. Because of their moisture holding, erosion prevention, and carbon sequestration and storage capabilities, grasslands will be crucial in mitigating climate change in the coming decades.

Apart from the environmental benefits of grasslands, they also offer economic ones. Primary uses for grasslands today are for livestock grazing and, when done correctly with rotational grazing and proper stocking rates, both grasslands and livestock benefit. The disturbance caused by livestock incorporates organic matter into the soils, encourages new vegetation growth, and diminishes the spread and establishment of invasive species. In return, livestock receives high-quality forage from various grassland vegetation.

Over the past few decades, the restoration and protection of these once "barren" landscapes has risen to the forefront of conservation with the increase in recognition of all that grasslands contribute to the environment. Prairies are resilient ecosystems that have evolved to withstand extreme climates and disturbances over millions of years, so conserving these ecosystems does not have to be difficult, requiring as little as proper livestock grazing rotations amongst pastures to prevent overgrazing and soil compaction and implementing prescribed burns to remove dead and invasive species. In situations like this, the Audubon Society works with ranchers to establish grazing practices that support grassland conservation and biodiversity. Conservation efforts will be more involved if attempting to convert croplands, or highly disturbed areas, back to grasslands. For these situations, some programs and organizations have been established to aid in these endeavors. For example, the conservation reserve program (CRP) is a government-funded opportunity for landowners who want to reestablish and protect grasslands. In this program, the US Department of Agriculture will contribute to the grassland's reclamation and pay the land owner a monthly rate for maintaining the grasslands to supplement other potential income from that conserved land. Landowners need to find the best program or organization for them and their long-term goals. Not every organization or program will be right for every landowner, and both parties must be on the same page before entering into a partnership. Recent studies have shown that the presence of bison on the landscape more than doubles the biodiversity of grasslands compared to grasslands without bison. These findings support the movement in recent years to reestablish bison herds throughout the great plains region.

Grasslands are high in biodiversity and provide crucial ecological and environmental functions. Though not as flashy as other ecosystems, grasslands are teeming with life and activity and play a crucial role in the ecological system. Despite this, conversion in the name of agricultural production and societal progress constantly threatens grasslands. Recently, grasslands have started getting recognized for all they do for the environment and are finally being restored and protected. The  USDA's Conservation Reserve Program ,  Grassland Conservation Reserve Program , the  Audubon Society,   The Nature Conservancy , and various conservation easement organizations are some examples of organizations that work with landowners and aim to protect this vital ecosystem. Grasslands are beautiful places, anyone from the great plains area will tell you that, but take a walk in one of the 20 national grasslands, and you'll get a sense of just how unique these areas are.

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