Somatic senescence: Evidence from female Richardson's ground squirrels

Article Abstract:

A study was conducted to highlight reproductive and somantic investments in more than 700 female Richardson's ground squirrels or known age over 14-year period to evaluate three hypothesis, restraint, senescence, and residual reproductive value, proposed to explain age-specific life history patterns in iteroparous vertebrates. It was found that reproductive investment, measured as litter mass at first emergence from the natal nest, did not differ among age classes.

United States, Ground squirrels, Animal reproduction

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Owl winter irruptions as an indicator of small mammal population cycles in the boreal forest of eastern North America

Article Abstract:

Collecting the information along with the databases, the presence of cycles in small mammals and their main avian predators by using temporal autocorrelation analyses is examined. The results suggest that a 4-yr population cycle exists in the eastern boreal forest of North America for voles and owls, which is very similar to the one observed in Fennoscandia.

North America, Mammal populations, Voles

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Detecting the causes of population cycles by analysis of R-functions: The spruce needle-miner, Epinotia tedella, and its parasitoids in Danish spruce plantations

Article Abstract:

An analysis of R-functions, the functional relationship between the per capita rate of change of a species and components of its environment that can be used to detect the causes of population cycles is presented. Analysis of the R-functions enables one to separate cycles due to negative feedback between species from those forced by one-way effects.

Denmark, Growth, Animal populations, Company growth, Spruce budworm

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