Interspecific Competition and Niche Differentiation in Ecology
1-Some experiments on interspecific competition have been monitoring the population densities of the species involved and their impacts on resources.
Why is it desirable to monitor both?
The monitoring of a single species can promote false results, so you should evaluate the species that compete in the middle, as is the case of diatoms that when separated into medium containing silicate survive, but when they worked together to survive Syneandra but reduces the level silicate, and Asterionella if present, can not survive because the level of silicate is very low.
2 – The interspecific competition may be a result of the exploitation of resources or direct interference. Give an example of each and compare their consequences for the species involved.
Exploitation can occur among individuals who do not have any physical contact and occurs when an individual consumes a feature making it unavailable for others, for example a frog and birds that eat grasshoppers. The interference competition requires direct interaction between competing individuals and one will be defeated, eg. Horse and a cow eating grass.
3 – Define fundamental niche and realized niche. How do these concepts help us understand the effects of competitors?
The fundamental niche of a species is a combination of conditions and resources that permit it to exist, grow and reproduce, when considered in isolation from any other species that could undermine its existence. Since the realized niche is the combination of conditions and resources that permit it to exist, grow and reproduce in the presence of other species, which may hinder its existence.
With this definition, we can understand the concept of competitors, since organisms compete for resources directly or indirectly, can affect other species with similar niches. Therefore it is necessary to make an analysis in the laboratory and another in nature, since they represent analysis of the fundamental niche and realized, respectively.
5 – Define the Principle of competitive exclusion.
When we see coexisting species with different niches, it is reasonable to conclude that this is the Principle in action?
The principle of competitive exclusion can be expressed as follows:
-If two competing species coexist in a stable environment, then they do as a result of niche differentiation, ie differentiation of their realized niches
– However, if there is no such differentiation or if it is blocked by habitat, then one of the contestants will eliminate or exclude the other
It is not reasonable to conclude that whenever observed, species coexisting with different niches, leads to the principle cited. Each species, when examined in detail, presents its own unique niche. The niche differentiation does not prove that there are competitors in coexistence.
There is need for evidence on the existence of interspecific competition, for example, through experimental manipulation.
6 – Explain how the heterogeneity of the environment could allow an apparently weak competitive coexist with a species that can delete it.
A species that is weak as a competitor in a constant environment can, for example, be efficient in the colonization of gaps in habitat caused by fire, storm … They can then coexist with a strong contender as soon as new gaps occur frequently enough. Thus, a realistic view of interspecific competition should recognize that this often does not occur in isolation, but under the influence and within the constraints of a fragmented world, volatile and unpredictable.
7 – What is the ghost of competition passed? Why is it impossible to prove the existence of an evolutionary effect of interspecific competition?
is that when species coexist in the same niche are not in competition, they simply coexist. They have evolved the ability to coexist and may look the same, at least superficially. Thus we can not prove the effect of interspecific competition. Taste means it can be applied to mathematical theorems or carefully controlled experiments in laboratories.
9 – Set of niche complementarity, and with the help of an example, explain how it can help explain the coexistence of many species in a community.
niche complementarity is when species that occupy a similar position in one dimension tend to differ in another dimension. EX: The calling site and the acoustic parameters of the advertisement for 18 species of frogs in six ponds in the northwest region of São Paulo (research described in Article Bioacoustics and calling sites in frog assemblages of open area in the northwest region) . The small species vocalize at a higher frequency and higher vocalize in a lower frequency. By analyzing the similarity in the use of calling site, habitat and the parameters of the advertisement, showing an overlay of the corner of only 11%. The structural homogeneity of the water bodies, the severe climate of the region and the high degree of conversion of the natural environment in areas restrict the abundance of populations and species richness. The low overlap in calling site is probably associated with the unsaturation of the sampled communities.