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Density-dependent mortality can be overcompensating, undercompensating or exactly compensating. [citation needed] There also exists density-independent inhibition, where other factors such as weather or environmental conditions and disturbances may affect a population's carrying capacity. [citation needed]
The causes of delayed density dependence vary in each situation. In lemmings, food supply and predation are the most important factors that lead to delayed density dependence. [3] Competition between life stages is another cause. In some species of moth the practice of egg cannibalism takes place where older moths eat eggs of their own species. [6]
The first variable is r (the intrinsic rate of natural increase in population size, density independent) and the second variable is K (the carrying capacity of a population, density dependent). [21] It is important to understand the difference between density-independent factors when selecting the intrinsic rate and density-dependent for the ...
Therefore, when the population density or size hits a number below this threshold, the population will be destined for extinction without any further aid. A strong Allee effect is often easier to demonstrate empirically using time series data, as one can pinpoint the population size or density at which per capita growth rate becomes negative. [1]
Populations of some species initially show a lack of response to density-dependent factors that limit population size as it nears the carrying capacity of the environment. The exhibition of irruptive growth is dependent on a number of elements including resource availability, degree of both interspecific and intraspecific competition, and ...
The rate at which a population increases in size if there are no density-dependent forces regulating the population is known as the intrinsic rate of increase.It is = where the derivative / is the rate of increase of the population, N is the population size, and r is the intrinsic rate of increase.
With that said, the Janzen-Connell effect plays a major role in the tree species’ relationship with gaps. The Janzen-Connell density dependent mortality model states that most trees die as seed or seedlings. In addition, host-specific predators or pathogens are predicted to be greatest where density is greatest, which is underneath parent tree.
Threshold host density (N T) only applies to density dependent diseases, where there is an "aggregation of risk" to the host in either high host density or low host density patches. When low host density causes an increase in incidence of parasitism or disease, this is known as inverse host density dependence, whereas when incidence of ...