(ECO) Biomes Chart: Grasslands Lesson

Biomes Chart: Grasslands Lesson

You will need your Biomes Chart for this. 

Complete the chart for each Biome in this module.  

These notes are useful for studying and can be a valuable resource for upcoming Biome assignments.

 

Grasslands Biome

 

Grassland biomes are large rolling terrains of grasses, flowers, and herbs. Latitude, soil, and local climates for the most part determine what kinds of plants grow in particular grasslands. A grassland is a region where the average annual precipitation is great enough to support grasses and in some areas a few trees. The precipitation is so erratic that drought and fire prevent large forests from growing. Grasses can survive fires because they grow from the bottom instead of the top. Their stems can grow again after being burned off. The soil of most grassland is also too thin and dry for trees to survive.

When the settlers of the United States moved westward, they found that the grasslands, or prairies as they called them, were more than just dry, flat areas. The prairies contained more than 80 species of animals and 300 species of birds. They also contained hundreds of species of plants.

There are two different types of grasslands; tall-grass and short grass. It is humid and very wet in a tall grass biome. A short-grass biome is very dry with hotter summers and colder winters than the tall-grass prairie. The settlers found both on their journey west. When they crossed the Mississippi River they came into some very tall grass, some as high as 11 feet. Here it rained quite often and it was very humid. As they traveled further west and approached the Rocky Mountains, the grass became shorter. There was less rain in the summer and the winters got colder. These were the short-grass prairies.

Grassland biomes can be found in the middle latitudes, in the interiors of continents. They can have either moist continental climates or dry subtropical climates. In Argentina, South America, the grasslands are known as pampas. The climate there is humid and moist. Grasslands in the southern hemisphere tend to get more precipitation than those in the northern hemisphere. Therefore the grass tends to be the tall-grass variety.

There is a large area of grassland that stretched from the Ukraine of Russia all the way to Siberia. This is a very cold and dry climate because there is no nearby ocean to get moisture from. Mountains do not block the winds from the Arctic. These are known as the Russian and Asian steppes.

In the winter, grassland temperatures can be as low as -40° F, and in the summer it can be as high 70° F. There are two real seasons: a growing season and a dormant season. The growing season is when there is no frost and plants can grow. It can last from 100 to 175 days. During the dormant season nothing can grow because it is too cold.

In tropical and subtropical grasslands the length of the growing season is determined by how long the rainy season lasts. But in the temperate grasslands the length of the growing season is determined by temperature. Plants usually start growing when the daily temperature reached about 50° F.

In temperate grasslands the average rainfall per year ranges from 10-30 inches. In tropical and sub-tropical grasslands the average rainfall per year ranges from 25-60 inches per year The amount of rainfall is very important in determining which areas are grasslands because it's hard for trees to compete with grasses in places where the upper layers of soil are moist during part of the year but where the deeper layers of soil are always dry.

As stated before, grasslands are found on every continent except Antarctica. Their location determines what they are called. There are three types of grasslands in North America: tall grasslands, mixed grasslands and short grasslands.

A savanna is a rolling grassland scattered with shrubs and isolated trees, which can be found between a tropical rainforest and desert biome. Not enough rain falls on a savanna to support forests. Savannas are also known as tropical grasslands. They are found in a wide band on either side of the equator on the edges of tropical rainforests.

Savannas have warm temperature year round. There are actually two very different seasons in a savanna; a very long dry season (winter), and a very wet season (summer). In the dry season only an average of about 4 inches of rain falls. Between December and February no rain will fall at all. Oddly enough, it is actually a little cooler during this dry season. But don't expect sweater weather; it is still around 70° F.

In the summer there is lots of rain. In Africa the monsoon rains begin in May. An average of 15 to 25 inches of rain falls during this time. It gets hot and very humid during the rainy season. Every day the hot, humid air rises off the ground and collides with cooler air above and turns into rain. In the afternoons on the summer savanna the rains pour down for hours. African savannas have large herds of grazing and browsing hoofed animals. Each animal has a specialized eating habit that reduces competition for food.

There are several different types of savannas around the world. The savannas we are most familiar with are the East African savannas covered with acacia trees. The Serengeti Plains of Tanzania are some of the most well known. Here animals like lions, zebras, elephants, giraffes, and many types of ungulates graze and hunt. Many large herbivores can survive here because they can move around and eat the plentiful grasses. There are also lots of carnivores too.

 

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