Tropical Rainy: Tropical Wet & Dry: Savannas

Tropical Savannas or Grasslands are associated with the tropical wet and dry climate type, but are not generally considered to be a climax community. Instead, savannas develop in regions where the climax community should be some form of seasonal forest or woodland, but continuous disturbances, such as drought or flooding, prevent the establishment of those species of trees. Tropical Savannas

Drought A long period of dry weather that can cause crop failure. 3 Photo credit: Dwigt Sieggreen

Heavy Rains & Floods When it rains too much at one time, rivers can flood their banks and cause soil erosion and other damage. 4

Climate A tropical wet and dry climate predominates in areas covered by savanna growth. Mean monthly temperatures are at or above 64° F and annual precipitation averages between 30 and 50 inches. For at least five months of the year, during the dry season, less than 4 inches a month are received. The dry season is associated with the low sun period. At times, parts of the savannas have temperature increases and precipitation decreases causing drought, where as, other times there is the opposite and flooding occurs.

Why is it important to learn about climate change in East Africa? Climate change affects all parts of the globe. Our actions in the US affect other countries. –How? Climate change in other parts of the world affects the US. –Why? What we learn about climate change in East Africa can help us understand climate change elsewhere. 6

Vegetation Savannas are characterized by a continuous cover of perennial grasses, often 3 to 6 feet tall at maturity. They may or may not also have an open canopy of drought- resistant, fire-resistant, trees, or an open shrub layer.

Climate Change affects Savanna Vegetation Different plants grow together Food for livestock Farming options Growing season: length and timing Type of crops grown Productivity of crops 8

Grazing Large mammals such as the elephant open woodlands by debarking the trees and by knocking them over. This opens the woodland to grass invasion and attracts a variety of grazing animals, including zebras, wildebeest, and the diverse antelopes of the Ethiopian province. Grazers will both eat and trample tree seedlings, inhibiting the regrowth of the woodland. Only well- armed species of shrubs and trees can establish themselves in the clearings. Overgrazing: if a grass savanna is overgrazed, patches of bare ground will be created. The bare ground will suffer from increased evaporation and only drought-resistant species can become established.

Livelihood Systems 10 People who live in the savannas have different roles in their community, most effected by the characteristics of their geographic location. Raise Livestock Farming Non-farm income

Farming 11 Photo Credit: Jennifer M. Olson

12 Photo Credit: Jennifer M. Olson Farm in Forest

Climate can have and effect on Crops Grown The growing season will shorten Corn will not grow in drier climates How much food the crops will yield 13

Raise Livestock 14

Non-Farm Income 15

Land Management Decisions about how to manage the land are made at different levels: Household Community Regional Land in the savanna can be used for: Grazing livestock Farming Wildlife Firewood and other uses 16

Farming 17 Photo Credit: Jennifer M. Olson Farm in Savanna

Farms Expanding into Savanna 18 Photo Credit: Jennifer M. Olson