Topic 21 Flashcards
Interspecific competition
interaction between individuals of different species brought about by a shared requirement for a resource in limited supply
Interspecific has a negative effect on..
both species, each species contributed to the regulation of the other population as well as its own
Interspecific has a less obvious effects than ..
predation (reduction in growth reproduction and survival)
Fundamental niche
full range of conditions/resources used by a species to survive/reproduce . (competition restricts a species to a portion of its fundamental niche)
Realized niche
the portion of fundamental niche a species actually explains as a result of competition (species may occupy the portion of their fundamental niche that doesn’t allow highest growth and reproduction)
Niche overlap
when 2 or more species use a portion of the same resource simultaneously (amount of overlap degree of potential competition for that resource)
3 possible outcomes when one species is introduced to an area where another species exist
- coexistence without competition (not limited)
- coexistence with competition (moderately limited)
- one species is eliminated (resource extremely limited)n
Coexistence with competition
results in reduction in 1 or both populations
Asymmetrical competition
one species is strongly affected
Competitively dominant
species least affected by competition
One species is eliminated
competitive exclusion principle
Competitive exclusion principle
2 spices that have the same resource requirement cannot coexist when those resources are scarce
Plants compete with neighbouring plants of the same or different species results in
changes in growth rates, plant size, shape, reproduction
Plant interactions are complicated by
- roots occupy soil
- stems and leaves occupy atmosphere
Root competition
water and nutrients (roots occupy soil)
Shoot competition
light (stems and leaves)
In competition between plants ..
even the stronger species will have a decrease in growth
Evidence in animals comes from
- contraction of a fundamental niche in the presence of another competing species
- expansion of a realized riche in the absence of another competing species (competitive release)
Experimental plots
remove one species and see how the other spices responds
Interspecific competition functionally reduces..
the carrying capacity of the environment for all species involved
Competitive exclusion
leads to number of questions: how can similar species compete for same limited resources and co exist? etc
Environmental gradients
abiotic factors or resources exist along a gradient (continuum) some portions will be optimal for particular species but not for others, results in on species having competitive advantages under one set of conditions
Temporal variations
allow for competitive advantages that change over time. changes which species will be the more successful competitor. no species reaches sufficient density to displace its competitor and both coexist
Multiple resources
interspecific competition often involves more than one single resource. competition for on resources effects the other resources. usually occurs in related species (territorial birds)
Resource partitioning
often species can coexist by resource specialization. reduce the bread of each species niche so there is no longer as much overlap. reduce competition each species exploits a portion of the resources unavailable to others
