population cycle

The most well known example of creatures which have a population cycle is the lemming.

A population cycle occurs where populations rise and fall over a predictable period of time.

Delayed density dependence has been used by ecologists to explain population cycles.

Lemming population cycles have long captured the human imagination.

In some cases these population cycles are spatially organised into a periodic travelling wave.

Population cycles of prey, particularly voles, have a considerable influence on breeding success.

In contrast to this, extrinsic factors like food supply and predation are held by other workers to control the population cycles.

Other causes of population cycles include cycling abiotic factors.

The number of litters per year varies with phase of population cycle (see below).

There is nothing new in the idea of population cycles, or in the suggestion that they may influence the business cycle (Losch 1937).

Ecologists have been unable to successfully explain regular population cycles for many decades delayed density dependence may hold the answer.

The insect has a natural population cycle of 8 to 10 years, but the speed of this year's resurgence has surprised experts.

But during peak population cycles?

'Only 3pc of the population cycle in built-up areas but there is a huge demand for safe off-road facilities.'

Consequently, the levels of the predator and prey populations cycle, and oscillate around this fixed point.

Litters average three to five leverets depending on latitude, elevation, and phase of population cycle, ranging from one to seven.

The weather, habit change, population cycles, contaminants, and productivity will be taken into consideration if the bald eagle population is declining.

The population cycle drives human history - from a eugenic phase into a dysgenic phase and eventual collapse.

A number of other species that are unrelated to either animal, as far as food chains are concerned, show population cycles of similar lengths.

There are some species where population numbers have reasonably predictable patterns of change although the full reasons for population cycles is one of the major unsolved ecological problems.

Normal population cycles do not occur when dispersal is prevented; under normal conditions, dispersers have been shown to be behaviorally, genetically, and demographically different from residents.

Short-term population cycles are well documented in populations that are not hunted but not in populations outside the park, which are hunted.

Ptarmigan has been considered as an indicator species for this process, although the natural population cycles of this bird do not seem to have been disrupted as yet.

Ecological and physiological aspects of the invertebrate fauna, studies on their adaptation to the Antarctic environment with special reference to population cycles, respiratory metabolism and cold tolerance etc.

The number of spawners necessary to maintain a healthy population might range from 1 million to 15 million, depending on whether the population cycle is at a peak or in a trough.