There was an African Savanna chosen to provide a case study analysis. During the case, study 4-agents chain was illustrated, which was an example of a small ecosystem. The first agent is the virus that interacts with the top predator in the African savanna. The main role of rinderpest (the virus) is to expand when the population of Wildebeest and contract when their population decrease (Exploring trophic cascade., n.d). From this perspective, the rinderpest has a direct interaction with Wildebeest. When analyzing the next stage of the supply chain, the top predator influences the wildflowers, so Wildebeest is also the first consumer in the ecosystem.
Turning to the vegetation, this is the main producer in the system, which starts the supply chain in this ecosystem. Moreover, it is the main “food” for fire. As more vegetation expands, more fire can be produced. In this case, there is a direct influence on the fire widespread. However, there are also some indirect effects provided in this supply chain. For example, rinderpest indirectly influences the amount of fire in the whole ecosystem. When the vaccination from rinderpest increase, the amount of burned vegetation steeply decreases due to the fact that there are more Wildebeest who eat the vegetation.
From the top predator’s effect perspective, the main advantage of this effect is the ultimate consumer’s presence in the ecosystem, which regulates the other supply chain’s functioning. However, when the direct predators over-consume the other agents, they may expand without any control. The immediate effect of the top predator is that it can affect the closest supply chain agent. Turning to the indirect effect, the primary consumers may be influenced by the top predator’s actions. When the middle agent is under-consumed by the ultimate predator, then the primary producer may decrease in population. Last but not least, when the top predator is removed, the whole system may be destroyed by the negative effect of the middle agent’s overpopulation. In our case, when the Otters disappeared, the Urchins became overpopulated in their existing area. As a result, the Kelps forestation extremely decreased, which destroyed the overall ecosystem in the sea.
Reference
Exploring trophic cascade. (n.d.). BioInteractive. Web.