grassland

Can you imagine standing in between tall grasses and wherever your eyes can see it is just 'grasses' swaying with the wind? Well, there are such places on Earth where grasses are spread out everywhere - such places are called Grassland. In this lesson, we will learn about this amazing area on our planet. 

What is a grassland? 

As the name says, grasslands are areas that are covered by various grass species. There are vast open areas of grasses.

There are three factors that maintain grasslands: 

1. Low rainfall - The grassland regions receive low precipitation which is just enough to allow the growth of grasses but not enough for larger plants like trees. Trees can be present, but they are infrequent.

2. Wildland fires - Fire is a natural part of the grassland ecosystem and helps maintain its health and vigor. It warms up the soil and reduces the leaf litter that accumulates each year, allowing sunlight to penetrate. After a fire, blackened fields quickly revive with new, green grasses and abundant, showy wildflowers.  Grassland animals are also prepared for fires, fleeing or burrowing underground to wait out the flames.

3. Grazing by animals - This also plays an important role in maintaining the ecosystem by stimulating plants to grow. This triggers biological activity and nutrient exchanges. Animals like deer, bison, and cattle compact the soil with their hooves and open new areas for seeds and the generation of plants to take roots. Large animals like African elephants also trample the ground and discourage the growth of trees. 

Do you know every continent has a grassland biome except one – Antarctica?

 

Types of grasslands

There are two main types of grasslands: tropical and temperate - with subcategories within each. 

Tropical grasslands

• Tropical Grasslands are also known as 'Savannas'.
• These are located near the equator, between the Tropic of Cancer and the Tropic of Capricorn.
• These are present in areas that have warm climate with a rainy season and a dry season. 
• Most of the precipitation falls during just a few months of the year. This results in a long dry season that inhibits the growth of trees. 
• Most notable of the tropical grasslands is the African savanna, which has an occasional tree and is home to many of the world's most spectacular species, such as elephants, giraffes, lions, and zebras. 
• Other than Africa, savannas are also found in South America, Asia, and Australia. 

Temperate grasslands

• Temperate Grasslands are located in the mid-latitudes, north of the Tropic of Cancer and south of the Tropic of Capricorn. 
• They are known for their rich soil that yields abundant growth of grasses. 
• Temperate grasslands are found in places such as North America and Eastern Europe. 
• Temperate Grasslands have a temperate continental climate, which is cooler than Savannahs.
• Temperate grasslands are known by different names in different locations - Prairies in North America, Steppes in Russia, Pampas in South America (Argentina, Uruguay, and Southeastern Brazil), Murray-Darling Basin in Australia, and Veld in South Africa

These two types of grasslands may look similar, but they differ in some significant ways. For example, elephants are found in African savannas but not in the temperate grasslands of the United States. In contrast, burrowing animals, such as prairie dogs, are commonly found in temperate grasslands.

Animals in grasslands

The animals that live in grasslands have adapted themselves to dry, windy conditions. The grasses in these areas support high densities of grazing animals like zebra, antelope, and bison. These herds in turn support predators like lions and cheetahs. The colour of many grassland animals blends in with the plants helping them to catch a prey or escape a predator. 

Most of the animals in Savvanah have long legs or wings to be able to go on long migrations. Many burrow underground to avoid the heat or raise their young. Animals don't sweat to lose body heat, so they lose it through panting or through large areas of exposed skin, or ears, like those of the elephant.

The following three factors make Savvanah the perfect place for birds of prey like hawks:

• the wide, open plain provides them with a clear view of the prey
• hot air updrafts keep them soaring
• occasional tree to rest on or nest in

With the interaction between grasslands and animals, the existence of grasslands is made possible because, without the grazing by Animals, they will be colonized by shrubs quickly and become woodland.

Plants in grasslands

As know, grasses are dominant plants in grasslands. Trees and large shrubs are rarely found in grassland areas. There are many species of grasses that live in this biome. Where they grow usually depends on the amount of rain that area gets. In wetter grasslands, there are tall grasses that can grow up to six feet high. In dryer areas, the grasses grow shorter, maybe only a foot or two tall. 

Common grasses in tropical grasslands include Bermuda grass, elephant grass, blue fescue, feather grass, Rhodes grass, red oats grass and lemongrass. These grasses generally go dormant during the dry period and then grow rapidly during the wet season. Because tropical grasslands do not go through cold periods like other regions, but instead growth and dormant periods, they tend to have more tree life than other grasslands.  Trees in tropical grasslands need to be specially adapted to this region that has porous, unfertile soil, many droughts and frequent fires. There are also more large and diverse animals in these regions, so trees need to protect themselves from grazers. As a result, many trees in these areas have deep roots, thick bark and toxic sap to prevent animals from stripping their sparse vegetation. Common trees in this biome include the candelabra tree, whistling thorn, jackalberry tree, umbrella thorn acacia, kangaroo paw tree, boabab, maketti tree, river bushwillow and black chokeberry.

Temperate grasslands have a high density of grasses and wildflowers. That's because grasses and wildflowers both tend to grow quickly from the bottom up, whereas trees and shrubs are easily killed by fires and usually require a lot of water to grow large. Common flowers in these regions include blazing stars, goldenrods, asters, milkweed, lupines, purple coneflower, clovers, sunflowers, and wild indigos. 

Impact of humans on the grassland biome

Due to their rich soil, temperate grasslands in the United States are prime targets for human development. Humans plow grasslands to plant wheat and other crops, replace wildlife with domestic livestock, and kill predators and prey alike. For example, the loss of grasslands in the United States due to agriculture nearly wiped out some of its iconic wildlife such as bison. Another example is that of decreasing population of monarch butterflies. During their long migration to Mexico, the monarch butterflies depend on the grasslands' wildflowers for food. As more and more grasslands in the United States have been converted into farmland, monarch butterfly populations have begun disappearing. In the African savannas, illegal hunting has resulted in the loss of many large animals, including elephants. The elephants crushes trees and shrubs, thus protecting the grasses. Without large animals around to stomp down the trees, they can more readily overtake the grasses, causing savannas to turn into forests. The resulting loss of the grasses would mean less food for grazing animals such as zebras and giraffes. 

Importance of grasslands

Grasslands are critical for the health of our natural world. 

• Protects soil from wind and water erosion.
• Provides high-quality, relatively inexpensive feed for livestock and wildlife.
• Provides valuable habitats for many plants, insects, birds, and other organisms
• Helps maintain soil fertility because it encourages higher levels of soil organic matter than row crops.
• Pollinators like bees and bumblebees thrive in grasslands where there are many kinds of flowers. 
• Grasslands' soil capture greenhouse gases and act as carbon sink. Much more than arable land and sometimes as much as forest soils.

There are conservation efforts going on to try and save the grasslands that are left as well as the endangered plants and animals.