Which of the Following Could Qualify as a Top-Down Control

Question

Which of the following could qualify as a top-down control on a grassland community?
A)limitation of plant biomass as a result of nitrogen deficiency
B)effect of grazing intensity by pronghorn antelope on plant species in the prairies
C)influence of rainfall on competition among plants
D)influence of shade on the abundance of flowering plants and ferns

Accepted Answer

Grazing intensity by pronghorn antelope is an example of a top-down control because it is a predator-prey relationship where the predator (pronghorn antelope) impacts the abundance and diversity of the plant species (prey) in the community. Limitation of plant biomass due to nitrogen deficiency, influence of rainfall on competition among plants, and influence of shade on the abundance of flowering plants and ferns are examples of bottom-up controls where abiotic factors influence the growth and reproduction of organisms in the community.