Grasslands are vast, open areas dominated by grasses, with few trees or shrubs. Found on every continent except Antarctica, these biomes are defined by their unique climate. Temperature, in particular, governs the character of these landscapes, influencing the soil and the species that thrive within them. The interaction between temperature and precipitation shapes the foundation of grassland life.
Temperature by Grassland Type
The world’s grasslands are broadly divided into two categories with distinct temperature profiles. Temperate grasslands, including the prairies of North America and steppes of Eurasia, experience a wide range of temperatures. Summers can be hot, with temperatures exceeding 100°F (38°C), while winters are cold, sometimes dropping to -40°F (-40°C).
Tropical grasslands, or savannas, are located closer to the equator in Africa, Australia, and South America. Unlike temperate grasslands, savannas have consistently warm temperatures year-round. Their climate is distinguished by alternating wet and dry periods instead of hot and cold seasons.
Seasonal and Daily Temperature Swings
A defining characteristic of many grasslands is extreme temperature variation. This is especially true for temperate grasslands due to continentality—their location in the interior of continents, far from the moderating influence of oceans. This distance from large bodies of water results in much hotter summers and colder winters than coastal areas at similar latitudes.
The lack of a dense tree canopy also contributes to significant daily, or diurnal, temperature fluctuations. During the day, the open landscape rapidly absorbs solar radiation, leading to high temperatures. After sunset, this heat radiates back into the atmosphere just as quickly, causing a sharp drop in temperature overnight.
How Temperature Shapes Grassland Ecology
The temperature of a grassland directly influences the adaptations of the plants and animals living there. Grasses, the dominant vegetation, have developed strategies to survive these conditions. During periods of intense heat and low moisture, many grass species enter summer dormancy, temporarily stopping growth to conserve resources. Their deep root systems are protected from the cold of winter and dry conditions.
Animals have also evolved behaviors to cope with temperature extremes. To escape summer heat or winter cold, many smaller animals like prairie dogs and ground squirrels dig extensive burrows where the temperature is more stable. Other animals, such as certain birds and large herbivores, may migrate to avoid the harshest seasonal temperatures. Hibernation is another strategy used to survive long, cold winters when food is scarce.
Impact of a Warming Climate
Global climate change is intensifying the temperature extremes in many grassland ecosystems. Rising average temperatures are leading to more frequent and severe heatwaves, stressing both plants and animals. These warmer conditions also contribute to extended droughts by increasing evaporation from soil and plants, which elevates the risk of wildfires.
The increased frequency of fires and prolonged droughts can favor some plant species over others, changing the vegetation’s composition. As the plant community changes, so do the animal species that depend on it for food and habitat. These cascading effects can lead to a transformation of the biome over time.