Chapter 6 - Interspecific Competition Flashcards
What is interspecific competition?
It is when individuals of one species suffer reduction of fecundity, survivorship, or growth due to exploitation of resources or interference by individuals of another species. It influences pop dynamics and species distribution.
How do competing species coexist?
They often are found coexisting on one spatial scale, but are found to have more distinct distributions at a finer scale of resolution.
How does interspecific competition affect species exclusion?
Species are often excluded from locations at which they could exist well in in the absence of competition.
What is a fundamental niche?
It is the combination of conditions and resources that allows a species to exist, grow, and reproduce when considered in isolation from species that may be harmful to its existence.
What is a realized niche?
It is the combination of conditions and resources that allows a species to grow and reproduce in the presence of other species that may be harmful to its existence.
What is niche differentiation?
It is the differentiation of realized niches that allows competitors to coexist (its not always easy to identify).
What is differential resource utilization?
It is when species compete but coexist by utilizing slightly different resources in slightly different ways.
ex. 2 bird species feed on tree beetles. One species will only eat beetles off of the bark while the other will only eat the beetles from the canopy and grass.
What is the Competitive Exclusion Principle?
It states that if 2 competing species coexist in a stable environment, then they do so as a result of a niche differentiation. If there is no differentiation (species competing for same resource in stable environment), then one competing species will eliminate or exclude the other.
Cannot always assume that when 2 species are coexisting that it is the principle in action, because all species have unique niches.
What is the Ghost of Competition Past?
It refers to coexisting species with the potential to compete that currently exhibit differences in behaviour, physiology, or morphology that ensures they compete little or not at all.
Coexisting present day competitors can look the same as coexisting species that evolved an avoidance of competition - b/c we can’t really know what happened in the past, but likely some kind of evolutionary change occurred at some point.
What is character displacement?
It is a morphological response to competition from another species.
ex. the reduced size of mongoose teeth in areas where there is larger competition, so it catches smaller prey (doesn’t occur in isolation)
What is ecological release from competition?
It is a response to the absence of ecological effects of other species.
ex. the mongoose is free from the limiting factor of competition in the east, so it is larger in comparison with the smaller one in the west that has lots of competition
What is niche complementarity?
It is niche differentiation in a community if species involving several niche dimensions
ex. for fish species of anemone, zone and food size are different dimensions of the niche
What is a guild?
It is a group of species that exploits the same class of environmental resources in a similar way.
What is intraspecific competition?
It is competition that occurs within a singular species.
What is a trade-off for interspecific competition?
Environments are not usually stable, so what one species may lack at, it will make up for it in a different aspect.
ex. a good disperser may be bad at fighting off other species
