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On expected lifetimes of small-bodied and large-bodied species of birds on islands

Article Abstract:

An analysis of the lifetime expectancy of small and large-bodied birds indicates the higher rate of extinction risk faced by small-bodied species due to the influence of changes in climate. The large-bodied species exhibit a greater increase in expected lifetime with size of population. The equation N(x) e enables a calculation of a population's expected lifetime, where x is a constant giving the rate of increase in lifetime with population, e is another constant and N, the expected population size on a long-term.

Birds, Extinction (Biology)

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On species-area relations

Article Abstract:

The logistic curve is the ideal model for estimating the richness of asymptotic species in a community or region. This was gleaned from the formulation of a general model that would consolidate the three species-area curves, namely, the exponential, the power and the logistic curve. The most appropriate model was selected using the probability associated with the usual F ratio (aggression mean square over the error mean square) of the analysis of variance table of the regression model as the best-fit criterion.

Models, Analysis, Biotic communities, Species, Species (Biology), Population biology

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Co-occurrence of morphologically similar species of stream fishes

Article Abstract:

A study of 219 minnow assemblages from the Red River basin, using a model of community assembly, shows that morphologically similar pairs of stream-fish species co-occurred less frequently compared to morphologically less similar pair indicating that only specific combinations of species can coexist. Those species that are morphologically different facilitate other species to utilize different resources.

Research, Behavior, Natural history, Fishes, Minnows, Red River (Southwestern United States)

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