In university I took a class in grassland ecology. As part of the class, we had to learn how to identify grasses using an identification key. Grasses were a group of plants I had never spent much time with, so I looked forward to learning more about them. Every week in the lab our instructor brought in several dried grasses (all that was available in the middle of winter) for us to work with. I took a sample of each grass and carefully worked through my key with it, step by step, making sure that I observed all the features of the grass correctly. If I got each step right, I would know what the species was. But somewhere, somehow, I went wrong. Often. I was usually good at identifying plants and using keys, but somehow in grasses I had reached my limit. Even today I have a certain respect for grasses because of this. Although there are a few species I recognize, for the most part I let grasses remain unnamed, and simply appreciate them in all of their mystery.
Grasses cover more land than any other group of plants, and are one of the most important plant families to humanity. Wheat, barley, oats, corn, and rice are grasses. So are sugar cane and bamboo. We use grasses in brewing, weaving, and building. Grasses feed our livestock and carpet our lawns. But despite their importance, grasses – especially native, wild grasses – are often ignored. Perhaps because they are not as showy as other flowering plants (probably many people do not even recognize that grasses do have flowers). Or maybe, since grasses generally are so common, we take them for granted and don’t notice them.
I can’t ignore grasses, because they’re a key part of one of my favourite ecosystems: grasslands. Temperate grasslands (also known as prairies, plains, steppes, downs, veld, and pampas) occur where summers are hot and winters are cool, and where it is too dry for trees to survive. Grasslands often receive less than 300 mm of precipitation in a year, and in the summer, the heat of the sun evaporates more water from the soil than rain puts in. Grasses succeed in these conditions because they have large fibrous root systems, ideal for absorbing any moisture in the soil. These fibrous roots are continually shed and replaced, enriching the grassland soil with organic matter. Above the ground, grasses have simple leaves, stems, and flowers (their flowers are pollinated by the wind, so they don’t need to be showy to attract insects) that die off in the hot, dry months of summer. Around here, the most common grassland grasses are perennial bunchgrasses, such as bluebunch wheatgrass (one of the few grass species I can confidently identify!) and fescues. Bunchgrasses are ideal for dry areas, because the shape of the standing dead leaves and stems creates a funnel-like shape that directs any rain water to the roots. In spring, when the soil is still moist from melting snow, the grass sends up fresh green shoots from a growing point just below the surface of the soil.
This low growing point can also allow the grass to regrow after a disturbance such as grazing or fire. And that’s important, because fire is a shaping force in the grasslands. Fires once burned the grasslands here every several years. The fires killed any tree seedlings that were starting to invade the grasslands, while grasses (with their growing points below ground) grew back. Native peoples of this region often started fires in the grasslands to improve habitat for desirable plants and animals. But since the nineteenth century, humans have suppressed wildfires, and many grasslands have been lost as trees have invaded.
Forest encroachment is only one of many threats to the grasslands. Today, temperate grasslands are one of the most altered biomes in the world. In the United States, less than 5% of the native grasslands remain. In British Columbia, that number is higher, but even here many grasslands have been lost to overgrazing, agriculture, urban development, and invasive plants. Humans are drawn to grasslands because of their warm, dry climates, beautiful scenery, and rich soils, but often we have not treated our grasslands well.
I think that many people do not recognize grasslands for the rich and diverse ecosystems that they are. Just as we often do not notice grasses, when we gaze out at a grassland, we see a landscape that looks empty, even wasted, just waiting for us to put it to use. The big trees of the coastal rainforests inspire awe and wonder, but a grassland can look harsh and desolate, especially from late summer to winter, when the above-ground growth of the grasses has largely died off and appears to be little in the grassland that is even alive.
But the grasslands are full of life, we just may have to look a bit closer to see it. The rich grassland soils are filled with thousands of species of bacteria, fungi, mites, and insects which help to break down organic matter shed by grass roots and make nutrients available for future plant growth. The surface of the soil is covered by a rich community of lichens, mosses, fungi, algae, and cyanobacteria that is known as the microbiotic or cryptogamic crust (“crypto”, for short, in my grassland ecology class). This crust, especially in the driest grasslands, is essential to help prevent erosion, reduce evaporation from the soil, and fix nitrogen from the air into the soil, where plants can use it.
In spring, the grasslands are filled with a burst of colour as wildflowers such as sagebrush buttercups, balsamroot, and the beautiful mariposa lily quickly grow and bloom to take advantage of the soil moisture after snowmelt. In late summer and fall, the sagebrush and rabbit-brush bloom, bringing a softer shade of yellow to the hills and roadsides. Prickly-pear cacti cluster among the rocks. Rattlesnakes, badgers, bighorn sheep, burrowing owls, meadowlarks, bluebirds, and many other animals make their homes here. In British Columbia, grasslands cover less than 1% of the province, yet contain close to a third of our endangered and threatened species.
And of course there are the grasses, which make the grasslands what they are. Their thin stems and leaves sway and rustle in the slightest breeze. On windier days, the waving grasses look like waves of the sea, flowing over the hills. Eight thousand years ago, the climate here was warmer than it is today, and grasslands were much more extensive than they are now. When I stand in the middle of a grassland, I find it is easy to imagine what that must have been like. Rolling hills of grass surround me – unnamed, rich with mystery and life. It seems like the grasslands go on forever, even though I know how small and threatened they are. I feel like I am standing in the middle of a world of grass.
If you would like to learn more about British Columbia’s grasslands, I recommend the book Spirit in the Grass by Chris Harris, which explores in photography, prose, and poetry one of BC’s largest remaining wild grasslands.