How competition and predation do affects species diversity and relationships between predator and prey in a community?
Hello Rk; Well, you’ve asked for a synopsis of a couple of upper division courses in ecology. The focus of your question is unclear but here is a thumbnail sketch of some possibilities.
1. Interspecific competition occurs when more than one species require access to a limited resource. The outcome is uncertain but typically results in the exclusion of one competitor from access to the resource OR it results in the limitation of the population of one or more of the participants. It may also preclude the immigration to the community by new species, thus placing a limit on diversity.
2. Predator/prey interactions increase the flow of energy through a community and, by limiting prey biomass, may contribute to increased diversity in the habitat occupied by the prey populations. I’m thinking of the interaction between Wolves and Elk in Yellowstone National Park in the USA. Without wolves in the system, the elk seriously overbrowsed the plant community around bodies of water. That reduced the abundance and diversity of birds, small mammals and beaver. With wolves in the system the elk avoid these mesic habitats and so now these other creatures are thriving.
3. The story goes on but maybe these two items suggest topics to think about.
Best regards, Jim Des Lauriers
Predator-prey relations refer to the interactions between two species where one species is the hunted food source for the other. The organism that feeds is called the predator and the organism that is fed upon is the prey. The predator prey relationship consists of the interactions between two species and their consequent effects on each other. In the predator prey relationship, one species is feeding on the other species. The prey species is the animal being fed on, and the predator is the animal being fed. Predators can affect the size of prey populations in a community and determine the places prey can live and feed. Herbivores can affect both the size and distribution of plant populations in a community and determine the places that certain plants can survive and grow. As the prey population increases, there is more food for predators. So, after a slight lag, the predator population increases as well. As the number of predators increases, more prey are captured. As a result, the prey population starts to decrease. Predators remove vulnerable prey, such as the old, injured, sick, or very young, leaving more food for the survival and success of healthy prey animals. Also, by controlling the size of prey populations, predators help slow down the spread of disease. Predators have profound effects throughout their ecosystems. Dispersing rich nutrients and seeds from foraging, they influence the structure of ecosystems. And, by controlling the distribution, abundance, and diversity of their prey, they regulate lower species in the food chain, an effect known as trophic cascades. Predation can have large effects on prey populations and on community structure. Predators can increase diversity in communities by preying on competitive dominant species or by reducing consumer pressure on foundation species. In the short run, competition should cause a reduction in the number of species living within an area, preventing very similar species from co-occurring. In the long run, however, competition is likely to increase species diversity, by acting as a force for specialization and divergence.As predator populations increase, they put greater strain on the prey populations and act as a top-down control, pushing them toward a state of decline. Thus both availability of resources and predation pressure affect the size of prey populations.