- Intraspecific competition
Intraspecific competition occurs when individuals of the same species compete with one another for resources such as food, water, and breeding sites etc. The greater the availablitity the larger the population.
- Interspecific competition
Interspecific competition occurs when individuals of different species compete for resources such as food, light, water, etc. Where populations of two species initially occupy the same niche, one will normally have a competitive advantage over the other. The population of this species will gradually increase in size while the population of other will diminish. If conditions remain the aame this will lead to the complete removal of one species.
No two species can occupy the same niche indefinitely when resources are limiting. shags and seagulls live on the same cliff face, however shags eat sand eels and seagulls eat fish, therefore they occupy different niches.