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Full-Text Articles in Ecology and Evolutionary Biology

Age-Structured Population Model With Cannibalism, Mmohammed El-Doma Dec 2007

Age-Structured Population Model With Cannibalism, Mmohammed El-Doma

Applications and Applied Mathematics: An International Journal (AAM)

An age-structured population model with cannibalism is investigated. We determine the steady states and study the local asymptotic stability as well as the global stability. The results in this paper generalize previous results.


Stability Analysis For The Gurtin-Maccamy’S Age-Structured Population Dynamics Model, Mohammed El-Doma Dec 2007

Stability Analysis For The Gurtin-Maccamy’S Age-Structured Population Dynamics Model, Mohammed El-Doma

Applications and Applied Mathematics: An International Journal (AAM)

The stability of the Gurtin-MacCamy’s age-structured population dynamics model is investigated. We determine the steady states and study their stability. The results in this paper generalize previous results.


Correlation Of Eastern Wild Turkey Poult:Hen Ratios With Population Indices To Detect Reproductive Density Dependence, Jay D. Mcghee, Jim Berkson Oct 2007

Correlation Of Eastern Wild Turkey Poult:Hen Ratios With Population Indices To Detect Reproductive Density Dependence, Jay D. Mcghee, Jim Berkson

Virginia Journal of Science

Knowledge of how density affects population growth is important for the harvest management of wild turkey. Unfortunately, available time-series are often too short for statistical detection of density dependence. The correlation between wild turkey recruitment and population size was assessed using data from 7 state wildlife agencies, circumventing the problem of short time-series by using multiple datasets. Correlation coefficients were calculated between surveyed poult:hen ratios and harvest-based population indices for 31 geographic or harvest management regions. Estimated correlation coefficients were tested for homogeneity to determine if an average correlation could be calculated. Correlation coefficients for the 29 regions ranged from …


An Age-Structured Resource-Consumer Dynamical Model, Jean M. Tchuenche Jun 2007

An Age-Structured Resource-Consumer Dynamical Model, Jean M. Tchuenche

Applications and Applied Mathematics: An International Journal (AAM)

Many dynamical systems in population biology in which agents compete for resources may exhibit chaotic fluctuations. This short letter develops Gamarra and Solé's previous work. We briefly review a classical model of population with complex dynamics, and proceed to study the dynamics of an age-structured resource-consumer model, in which the fertility coefficients are density independent. Implicit or first integral solutions of the model are obtained, and conditions for which they are stable given. It is observed that resource availability at any time depends on the number of potential consumers present.


A Checklist Of The Amphibians And Reptiles Of México, Ernest A. Liner May 2007

A Checklist Of The Amphibians And Reptiles Of México, Ernest A. Liner

Occasional Papers of the Museum of Natural Science, Louisiana State University

No abstract provided.


Phytoplankton Productivity In The Tidal Regions Of Four Chesapeake Bay (U.S.A.) Tributaries, Kneeland K. Nesius, Harold G. Marshall, Todd A. Egerton Jan 2007

Phytoplankton Productivity In The Tidal Regions Of Four Chesapeake Bay (U.S.A.) Tributaries, Kneeland K. Nesius, Harold G. Marshall, Todd A. Egerton

Virginia Journal of Science

Monthly and annual phytoplankton productivity rates of four Virginia tidal rivers were determined based on a 12-year monitoring study that included sampling stations from tidal freshwater, oligohaline, and mesohaline regions in these rivers. The mean monthly rates and range at these locations were 5.52 (Dec.) to 175.12 (Aug.) mg C m-3 h-1 for tidal freshwater, 12.21 (Jan.) to 149.90 (May) mg C m-3 h-1 in oligohaline regions, and 16.20 (Jan.) to 151.33 (May) mg C m-3 h-1 for the mesohaline. The estimated mean annual 12 year productivity for the different Virginia river sites in …