Grassland is a semiarid biome characterized by warm, humid summers with moderate rain and cold, dry winters. The central valley of California is an exception; it is a winter-rainfall grassland at a lower than typical elevation. Grass is the dominant life form; scores of species form a nearly continuous cover over large areas. Other well-represented life forms are annuals and geophytes herbaceous perennials such as bulbs that die to the ground each year.
Populations of trees, shrubs, and succulents are kept at low levels by periodic fires during the dry season. Most of the grasslands in the western states are intermediate between the true prairies of the American Midwest and deserts. They are called semi-desert or desert grasslands.
Compared with prairie grassland, the grasses in desert grassland are shorter, less dense, and are more frequently interspersed with desert shrubs and succulents. Desert grassland or chaparral borders the northern Sonoran Desert on the east. Nowhere else can you see this sight: black-tailed prairie dogs in an Arizona grassland. Once numerous over their small range in this state, now they're completely gone.
Grasslands, like the Little Missouri National Grassland in the United States, fill the ecological niche between forests and deserts, often bordering the two. This lists the logos of programs or partners of NG Education which have provided or contributed the content on this page. Leveled by. Monday, March 30, Grasslands go by many names.
In the United States Midwest, they're often called prairies. In South America, they're known as pampas. Central Eurasian grasslands are referred to as steppes, while African grasslands are savannas. What they all have in common are grasses, their naturally dominant vegetation. Grasslands are found where there is not enough regular rainfall to support the growth of a forest, but not so little that a desert forms. In fact, grasslands often lie between forests and deserts. They are generally open and fairly flat, and they exist on every continent except Antarctica, which makes them vulnerable to pressure from human populations.
Threats to natural grasslands, as well as the wildlife that live on them, include farming, overgrazing, invasive species, illegal hunting, and climate change. At the same time, grasslands could help mitigate climate change: One study found California's grasslands and rangelands could store more carbon than forests because they are less susceptible to wildfires and drought.
Still, only a small percentage—less than 10 percent—of the world's grassland is protected. Types of Grasslands There are two main kinds of grasslands: tropical and temperate. Examples of temperate grasslands include Eurasian steppes, North American prairies, and Argentine pampas. Tropical grasslands include the hot savannas of sub-Saharan Africa and northern Australia. Rainfall can vary across grasslands from season to season and year to year, ranging from Temperatures can go below freezing in temperate grasslands to above The height of vegetation on grasslands varies with the amount of rainfall.
Some grasses might be under 0. Their roots can extend 0. The combination of underground biomass with moderate rainfall—heavy rain can wash away nutrients—tends to make grassland soils very fertile and appealing for agricultural use. Deserts and grasslands are biomes known for their low precipitation and lack of trees.
They are found on nearly every continent and within close proximity of each other. The lack of water and other key resources makes life in these climates difficult and challenging, but not impossible. Nevertheless, both deserts and grasslands are thought of by residents of other climates as being unique and exotic, and both are home to rare wildlife. Deserts and grasslands have very high summer temperatures that are not found in other climate zones, except tropical rain forests.
The deserts of Libya as well as Death Valley, California have exceeded degrees and are the hottest places on earth. Grasslands in the central United States and sub-Saharan Africa exceed degrees in the summer.
The same is true for the steppes of Kazakhstan and Central Asia. Though cool and even cold temperatures visit grasslands and deserts during the winter, they are the most arid places on earth, especially during the summer.
0コメント