An ecosystem includes all the plants and animals in a specific region and the abiotic factors they interact with. An ecosystem of the savanna is the African savanna. A biome is an ecosystem class that is categorized by vegetation for terrestrial biomes and physical environments for aquatic biomes. Biomes are also categorized by specific adaptations of animals and plants in a certain environment. The biome included in this book is the savanna biome.

Climate is a long-term weather condition in a particular region. The climate in the savanna depends on whether it is a dry or wet season in the savanna. During the dry season, there is no rainfall. During the wet season the savanna gets all of its rain, which is around 10 to 30 inches. A climograph is the graph of the temperature and rainfall in a certain region. Disturbance is a natural or human oriented occurrence that alters a natural community and animals and plants could possibly be removed or drawn away from that community. Some examples of a disturbance to the savanna are fires and hunting and poaching.

The savanna is a grassland with scattered trees and shrubs. Savannas are located between tropical rain forests and deserts. Savannas can also be called tropical grasslands. Savannas are located on either side of the equator near the edges of tropical rain forests. The savanna has two different seasons the dry season and the wet season. During the dry season only an average of four inches of rainfall occurs. During the wet season an average of 10 to 30 inches of rainfall occurs. The major rainfall occurs in May. The average temperature of the savanna during the dry season is between 68 and 78 degrees Fahrenheit. During the wet season the average temperature of the savanna is between 78 and 86 degrees Fahrenheit.

The most familiar savannas are the East African Savannas and Serengeti Plains of Tanzania. There are also savannas in South America, but not as many species live there. Brazil, Colombia, and Venezuela together have a savanna biome that is as big as one-fourth the size of Canada. Savannas cover over two-fifths of Africa. They are also located in Australia and India. In all, savannas cover around 20 percent of earth.

An abiotic factor is any nonliving physical or chemical property of an environment. One abiotic factor that affects the savanna is rainfall. There are three types of savannas depending on the amount of rainfall: wet, dry, and thornbush savannas. The wet savannas have the shortest dry season. It lasts between three and five months. The dry savannas have a dry season for five to seven months. Thornbush savannas have a dry season for over seven months. Rainfall can affect the ecosystem because during the dry season water supplies go down and the animals have to find new sources for water. Animals can also compete for scarce water and food sources and possibly die because of dehydration.       

Another abiotic factor that affects savannas is soil. Typically soil in savannas is very low fertility. The most fertile soil is located in areas under the trees because of the fallen leaves. Climate change is also an abiotic factor that affects the savannas. According to the Biological Dictionary, data shows that savannas may increase or decrease in size because of the greenhouse effect. The animals and plants will be affected because the savannas might not be able to adapt and change in time to the rising carbon dioxide in the air. It is possible that certain savannas will no longer exist in the future because they will not adapt in time. 

Biotic factors are the living factors in an environment. One biotic factor that affects the savanna are termites. They affect savanna trees because they cause the soil to become more fertile. Termites create 30 percent of the decomposed organic matter in the savanna. This is because their mounds break down and fertilize the soil.      

Another biotic factor that affects the savanna are humans. The main thing that humans do to affect the savanna is start fires. The fires can be accidental or on purpose. Fires in the savanna can easily start and spread quickly, especially during the dry seasons. This affects the savanna because then the vegetation is destroyed and animals loose food and their habitat. Another concern that the humans cause for the savanna is hunting and poaching. Hunting and poaching has caused animals to appear on the endangered list. Such animals include: cheetahs, elephants, rhinos, hippopotamuses, and the African wild dogs. If nothing is done to stop the hunting and poaching of the animals, they will become extinct. 

A density-dependent factor in the savanna is migration. The animals in the savanna migrate because of the wet and dry seasons. Their food source is normally scarce during the dry season so the animals have to follow their food source to stay alive. Animals might also have to migrant to follow water sources since it does not rain during dry seasons. One example of this is the elephant. The elephant migrates to wherever their water source goes so they do not dehydrate and die. Elephants are also herbivores so wherever their water source is they will also have plenty of vegetation to graze on. Another example of an animal that migrates in the savanna is the hyena. Hyenas both hunt their own prey and act as scavengers. Meaning that they will kill and eat their own prey, and eat someone else’s prey even though they did not kill it. Hyenas have to migrate towards wherever their prey moves during the dry season. 

Density-independent factors that affect the savanna are climate and weather.  The climate in the savanna is always warm since savannas are located near the equator. The average temperature of the savanna during the dry season is between 68 and 78 degrees Fahrenheit. During the wet season the average temperature of the savanna is between 78 and 86 degrees Fahrenheit. The savanna only rains during the wet season, or summer time. The average rainfall during the wet season is between 10 and 30 inches. During the dry season, or winter, there is no rainfall. The dry season of the savanna causes species to migrate or die, since there is no rain. Without rain there is little water and a smaller amount food. An example of a species that is affected by the dry season of the savanna is the wildebeest. During the dry season the wildebeest has to find new water sources while still trying to protect themselves from being hunted by secondary and tertiary consumers. Another species that is affected by the dry season is the dry season is the giraffe. Giraffes also have to move during the dry season to find a proper water source so that they do not dehydrate and die. 

There are many different types of organisms that are found in the savanna. Some producers found in the savanna include: Rhodes grass, red oats grass, lemon grass, Jackalberry trees, and acacia trees. The producers make their own energy and nutrients. A couple primary consumers found in the savanna are cows, warthogs, impalas, and zebras. Primary consumers mainly just eat vegetation. Some secondary consumers found in the savanna are leopards, jackals, African wild dogs and hyenas. The secondary consumers are carnivores or omnivores. Tertiary consumers are lions and cheetahs. The tertiary consumers are organisms that they eat both secondary consumers and primary consumers. 

Cheetahs, elephants, rhinos, hippopotamuses, and African wild dogs are the endangered species of the savanna. They are endangered because of human hunting and poaching. They could also be possibly endangered because of the fact that humans release their cows and other farm animals onto the savanna to graze. This causes less food availability to the wildlife. Actions being done to help the endangered species is that each country has established game reserves and national parks to help protect the animals. In the reserves and parks hunting is not allowed. There are also areas where tourists can come in and see the animals, which raises funding to protect the animals. Hunters can still go hunting, but they go on regulated safaris to makes sure they are only hunting what can be hunted. 

Carnivores (tertiary consumers): Lions, leopards, and cheetahs     

Scavengers (secondary consumers): Hyenas and vultures

Insectivores (secondary consumers): Red-billed oxpecker  

Herbivores (primary consumers): impalas, warthogs, zebras, giraffe, and elephants

Decomposers (primary consumer): termites    

Producers: acacia tree, Jackalberry tree, Rhodes grass, red oats grass, and lemon grass 

    An example of a predator prey relationship in the savanna ecosystem is the relationship between the whistling-thorn Acacia tree and ants. The whistling-thorn Acacia tree produces large thorns called domatia, which allow plants to live in them. In return, the ants fight off the wood-boring beetles that injure the plant. This relationship is mutualistic because the whistling-thorn Acacia tree gives the ants a place to live, and the ant protect the tree from being injured by the wood-boring beetle.