Grassland plants don’t get enough attention from conservationists, writers, filmmakers, or policymakers. Most people know next to nothing about grasslands, other than the obvious fact that they are grassy. I’m here to show you that grasslands are dynamic places full of all sorts of wonder.
What Is a Grassland?
A grassland is an ecosystem dominated by plants in the grass family, Poaceae. This type of ecosystem began to take over about 6 million years ago, which is relatively recent in terms of geology. Around this epoch, the world’s climate began to dry out and got colder due to polar ice caps sucking up moisture. This climate made life more difficult for forests, which died off in places like the middle of North America and the steppe of Central Asia.
As grasslands expanded, so too did the charismatic megafauna we associate with them. Elephants, lions, gazelles, and hundreds of other species extended their range throughout Africa, Asia, and the Americas (yes, there were lions, giant beavers, and wooly mammoths that lived in the U.S. before humans got here).
But how did grasslands persist once the climate shifted again? Well, grasslands evolved to deal with frequent fires. These fires killed any woody shrubs and trees trying to grow in the grasslands but didn’t kill the grasses. Grazers also ate tasty woody plants trying to gain a toehold in the grasslands. Lastly, as we will explore later, grassland root systems are so tightly woven that it is difficult for other plants to establish in a mature grassland.
What Are the Different Kinds of Grasslands?
There are three main types of grasslands in the world: natural, semi-natural, and so-called ‘improved.’ ‘Improved’ grasslands are agricultural grasslands- think corn in the midwest. Farmers replaced native plants with non-native grasses to harvest frequently as a crop.
Semi-natural grasslands are managed for hay or other fodder. However, they don’t see the application of fertilizers and herbicides. Semi-natural grasslands can make for important wildlife habitats because they contain a number of species, rather than just a single crop.
Natural grasslands are those that haven’t been plowed. They are grazed by cattle, sheep, goats, or natural grazers. These grasslands are increasingly rare as they get converted to ‘improved’ grasslands. This article focuses on natural and semi-natural grasslands because their plants are more interesting than corn and wheat.
So, now that we know what grasslands are, let’s take a look at why we would care about grassland plants!
Grassland Roots Provide Invaluable Services
Perhaps the most intriguing aspect of grasslands lies in the roots of the grasses. While they may look simple on the surface, there is a ton going on underneath the soil. Unlike forests, which put most of their growth aboveground, grasslands focus 80% of their growth belowground.
This means that for every pound of grass that you can see, that plant has put five pounds of matter beneath the soil. Moreover, these roots build on top of the previous year’s growth, whereas the leaves die back every year. Some grasses have roots that extend 15 feet into the soil!
This awesome root network the main reason that grasslands make great agricultural soils. The vast roots add tons and tons (literally) of carbon into the soil over centuries. This carbon provides food for all sorts of fungi, bacteria, and animals in the soil. These organisms along with the rich carbon provide plants with abundant nutrients for growth. When farmers turn grasslands into crops, they start with rich topsoil that can be turned into impressive amounts of corn and wheat. This is why humans turned 80% of grasslands in North America into croplands.
Grassland Plants Sequester Monster Amounts of CO2
Grassland roots are useful for something else: taking CO2 out of the atmosphere. As plants grow, they breathe in CO2 and add it to their bodies. This is helpful for climate change because CO2 causes global warming. Plants store this carbon over their lifetime until they die and decompose or are burned in a fire.
Forests are hugely beneficial for carbon sequestration because they are productive ecosystems that have enormous biomass. However, as forest fires become more severe and common with climate change, forests can pose as a risk rather than an asset. If a forest burns to the ground, all of that carbon stored over centuries floats into the air as CO2, furthering global warming.
Researchers are UC Davis found that grasslands are more reliable carbon sinks than forests in modern-day California. This is because of those special roots. If a grassland burns, only about 20% of the carbon goes into the air because 80% of the carbon is underground, where the fire won’t burn. In a place with increasing wildfires, such as California, a grassland is a safer long-term bet for carbon storage.
That being said, forests remain the world’s best source of carbon sequestration, and we shouldn’t write them off. But just remember that grasslands contain about 12% of terrestrial carbon, which is no small amount.
Grasslands Are More Biodiverse Than Rainforests
Yeah, you read that right. And it’s true (sometimes). While rainforests are undoubtedly the most biodiverse places on the planet on a large scale, grasslands have them beat in small areas. In places under 100 square meters, grassland plants are usually more diverse than rainforests.
Researchers found 131 plant species in a 500 square foot area of grasslands in the Czech Republic! Even more impressive, scientists found 43 species of plants in just one square foot in Estonia, a world record. That’s equivalent to three species of plants growing on an area the size of your phone!
Grasslands can be so diverse because there isn’t huge competition for sunlight. In forested ecosystems, trees catch the majority of the light, preventing plants in the understory from getting as much sun. Since grasslands start anew each season, the playing field is more or less equal for all the competing species.
You can be sure that a dizzying diversity of insects accompanies all of these grassland plants as pollinators and herbivores. Similarly, an exciting variety of birds and mammals call grasslands home.
Aesthetic Value Of Grassland Plants
Alright, sometimes grassland plants are cool just because they look cool. Check out that purple coneflower, or echinacea, at the top of the article. Beautiful, right? Big bluestem, the picture just above, is a grass that can grow up to 12 feet in the right conditions. In the fall it turns a brilliant red and yellow.
Granted, grasslands take a little more effort to appreciate than rugged mountains or a lovely beach. You’ve got to get on your hands and knees and take time to really see what’s going on. Try it! One of the best places to catch exciting grassland plants is next to train tracks because those areas haven’t been disturbed by farming or grazing. If you want to check out more fun pictures of grassland plants, check this out.
Rarity of Grassland Ecosystems
A lot of people get excited about rare things. If that resonates with you, you should definitely be excited about grassland plants. The tallgrass prairie of North America is the rarest ecosystem in the world. Only 1-4% of it is left, and most of that is in the Flint Hills of Oklahoma and Kansas. The rest is now agriculture, urban, or unsustainably grazed.
Globally, grasslands are threatened ecosystems. About 15.5% of terrestrial land is conserved in some way or another, but only 4.5% of grasslands are protected. They aren’t immediately charismatic or breath-taking, but they still require conservation. They filter our water, take the carbon out of our air, prevent our soil from eroding, and provide food for animals and humans around the world!
I hope this article has inspired you to care a little bit more about grassland plants. Next time you find yourself driving next to a good looking grassland, try pulling over and exploring it for yourself. You may be surprised at what you find!