Tropical Savanna

1. Tropical Savanna Billy Godin Houlton Bonel

2. Location Some of the savannas are located in South America and South East Asia

3. Climate In the savanna climate there is a distinct dry season, which is in the winter. Savannas get all their rain in the summer months. During the distinct dry season of a savanna, most of the plants shrivel up and die. Some rivers and streams dry up. Most of the animals migrate to find food. In the wet season all of the plants are lush and the rivers flow freely. The animals migrate back to graze. In West Africa the rainy season begins in May. It is usually cooler during the dry season by a few degrees. Because it is in the tropical latitudes that is still hot enough. The savanna climate has a temperature range of 68° to 86° F (20° - 30° C). In the winter, it is usually about 68° to 78° F (20° - 25° C). In the summer the temperature ranges from 78° to 86° F (25° - 30° C). In a Savanna the temperature does not change a lot. When it does, its very gradual and not drastic. There is an annual precipitation of 10 to 30 inches (100 to 150 cm) of rain. From December to February hardly any rain falls at all.

4. Defining Features • a rolling grassland scattered with shrubs and isolated trees • can be found between a tropical rainforest and desert biome • Not enough rain falls on a savanna to support forests. • known as tropical grasslands. • found in a wide band on either side of the equator on the edges of tropical rainforest • Savannas have warm temperature year round. • 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. • it is actually a little cooler during this dry season; 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.

5. PlantAdaptations. 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. South America also has savannas, but there are very few species that exist only on this savanna. In Brazil, Colombia, and Venezuela, savannas occupy some 2.5 million square kilometers, an area about one-quarter the size of Canada. Animals from the neighboring biomes kind of spill into this savanna. Plants have adapted to growing for long periods in standing water.. There is also a savanna in northern Australia. Eucalyptus trees take the place of acacias in the Australian savanna. There are many species of kangaroos in this savanna but not too much diversity of different animals

6. Animal Adaptations… During the rainy season, birds, insects, and both large and small mammals thrive in the savannah, but the rainy season only lasts 6 to 8 months. During the dry season, surface water from the rain is quickly absorbed into the ground because the soil is extremely porous. Competition for water during the dry season is intense. Consequently, most birds and many of the large mammals migrate during the dry season in search of water. Because drought conditions are sometimes localized, the migration may be just to another area within the savannah. When drought conditions exist for a long time and over a wide area, the animals may migrate to another biome until the rainy season begins again.

7. Climate change There exists the possibility that human induced climate change in the form of the greenhouse effect may result in an alteration of the structure and function of savannas. Some authors have suggested that savannas and grasslands may become even more susceptible to woody plant encroachment as a result of greenhouse induced climate change. However, a recent case described involved a savanna increasing its range at the expense of forest in response to climate variation, and potential exists for similar rapid, dramatic shifts in vegetation distribution as a result of global climate change, particularly at acetones such as savannas so often represent. Somethreats… Tree clearing Large areas of savanna have been cleared of trees, and this clearing is continuing today. For example until recently 480,000 hectometers 100 meters squared) in Australia alone primarily to improve pasture production. Substantial savanna areas have been cleared of woody vegetation and much of the area that remains today is vegetation that has been disturbed by either clearing or thinning at some point in the past.

9. videos http://www.youtube.com/watch?v=SZOGNpkAag8 http://www.youtube.com/watch?v=Tuk-JW-wng0