Grasslands are open areas where grasses or grass-like plants are the dominant vegetation and where there are few trees. Grasses came to dominate over other species, such as trees, because they are better able to thrive in hot, dry climates where spring and summer rain is sparse.
Grasses take advantage of moisture in the soil during spring and have many long, fine roots to search for water at, and just below, the surface of the soil. The blades of grass plants curve inward to capture rain drops and direct them into the centre of the plant, where they are absorbed by the roots. By mid-July in British Columbia, grasses have gone to seed and the plants are drying out. A layer of mulch and a crust of mosses, lichens, liverworts and other organisms on the ground between the grasses help to shade the ground from summer heat and from wind, thus preventing evaporation of precious water from the root zone below.
Grass pollen is distributed by the wind that blows constantly in these dry, open areas. Grass seeds themselves are tiny cylinders, often with a long thread-like "awn" on the end, allowing them to move into cracks in the ground towards moisture. The awns of some grasses, such as needle and thread grasses, are tiny spirals that enable the seed to actually bore into the ground – or your socks as you brush against the plant.
Grasses also reproduce vegetatively either by producing mini grass plants from the roots called "tillers" or by sending out underground shoots called "rhizomes". Both these methods ensure that grass plants can spread without the need for seeds, allowing them to become established in areas before other plants that need to set seed to reproduce.
Grasses are also able to withstand grazing and fire. The growing point of most plants is situated at the tip of a leaf or shoot, but in grasses it is at the base, close to the ground. When a grass plant has been grazed or burned it is able to grow again from this protected base.
Grasses are not the only plants in grasslands. Many flowering plants, also called forbs, have adapted to the hot, dry climate, completing their cycle of flowering, seed formation and drying out before the hottest part of the summer. Forbs become more abundant with elevation and can create spectacular displays when in bloom.
Shrubs are also an important component of grasslands, and in some areas they are the dominant plant. Big sagebrush, antelope-brush and rabbit brush are common in lower elevation grasslands in British Columbia; all have long, deep tap roots that search for water well below the surface.
The rolling landscape of grasslands includes hills, river valleys, canyons and cliffs. All these features alter the amount of sun and precipitation a specific part of the landscape receives. Elevation also influences temperature and precipitation: at higher elevations days are cooler and shorter, precipitation is higher and snow stays longer. Some areas of the grasslands are hot and dry while others may be relatively cool and moist.
Water runs over the landscape in the form of rivers, streams and small creeks, collecting in low areas to form lakes, ponds, wetlands and moist ground. The combination of landscape features, elevation and climatic differences create a mosaic of plant communities and habitats that includes: open grasslands; rocky talus slopes and rock outcrops; riparian areas; wetlands; ponds and lakes; gullies; aspen stands; open coniferous forests; and closed coniferous patches.
Distinct plant and animal species live in grasslands; they are adapted to living where drought is common, summers are long and hot, and winters are cold and relatively dry. Many animals that live in grasslands are grazers, like the California Bighorn Sheep, and many, like the marmot, burrow underground. Some animals, such as the Sharp-tailed Grouse, use both the grasslands and nearby forests during the year, while others such as the Western Harvest Mouse (vole) spend their whole lives in the grasslands.
Where in the world are grasslands?
Where are BC's grasslands?
Kristi Iverson (Grass Photo)
Anna Roberts (Grassland setting)
Roy Cranston (Wildlife Collage)