The use of surrogate species is an important tool in predicting the effects management decisions or establishment protective measures for endangered/threatened species. While relying on a handful model to predict fate scores distantly related target has been criticized, quantitative measure linking life history traits and population predictions sorely missing. We derive here closed-form expression aimed at determining conditions under which sublethal toxicant outcomes will reliably (listed)...

Long-term monitoring of endangered species abundance based on acoustic recordings has not yet been pursued. This paper reports the first attempt to use multi-year passive data study impact Deepwater Horizon oil spill population sperm whales. Prior Littoral Acoustic Demonstration Center (LADC) collected near site in 2007. These baseline now provide a unique opportunity better understand how affected marine mammals Gulf Mexico. In September 2010, LADC redeployed recording buoys at previously...

Wetland habitats are besieged by biotic and abiotic disturbances such as invasive species, hurricanes, habitat fragmentation, salinization. Predicting how these factors will alter local population dynamics community structure is a monumental challenge. By examining ecologically similar congeners, Iris hexagona I. pseudacorus (which reproduce clonally sexually tolerate wide range of environmental conditions), one can identify life-history traits that most influential to growth viability. We...

The use of the surrogate species concept is widespread in environmental risk assessment and efforts to protect that provide ecosystem services, yet there are no standard protocols for choice surrogates. Surrogates often chosen on basis convenience or vague resemblances physiology life history concern. Furthermore, our ability predict how concern will fare when subjected disturbances such as contaminants toxicants based woefully misleading comparisons static toxicity tests. Here we present an...

Prolonged exposure to disturbances, such as toxicants, has the potential result in evolutionary responses a population. These may impact not just that species but also other with which population interacts. In this paper, we develop discrete-time predator–prey model and establish conditions for existence stability of equilibria, well persistence prey predator populations. We then extend an couples dynamics evolving phenotypic trait provides measure level toxicant resistance developed by...

We study SIR and SIS epidemic models with multiple pathogen strains. In our we assume total cross immunity, standard incidence, density-dependent host mortality. derive conditions on the parameters which guarantee competitive exclusion between n An example is given to show that if these are not satisfied then coexistence strains possible. Furthermore, numerical results presented indicate sufficient but necessary for exclusion.

In this paper we address the basic mathematical properties of a general population model having distributed growth and mortality rates. The problem considered generalizes previous efforts [3] in three ways. First, our involves nonlinear terms. Second, parameter space is assumed to be any compact subset (0,∞) x (0, ∞), third, solutions rate distribution are constructed spaces measures. latter point particularly appropriate for asymptotic behavior, which survival fittest manifests itself as...

Abstract In this paper we consider the "fully nonlinear" size structured population model. We develop an implicit finite difference scheme to approximate solution of nonlinear partial differential equation. The convergence approximation a unique bounded variation model is obtained. Numerical results example problem are presented. Keywords: AMS subject classification.35A40AMS classification.65M06AMS classification.92D25.

A nonautonomous nonlinear continuous juvenile-adult model where juveniles and adults depend on different resources is developed. It assumed that are structured by age, while size. Existence-uniqueness results proved using the monotone method based a comparison principle established in this paper. Conditions parameters lead to extinction or persistence of population obtained via upper-lower solution technique.

Objective: The misuse and abuse of alcohol among college students remain persistent problems. Using a systems approach to understand the dynamics student drinking behavior thus forecasting impact campus policy address problem represents novel approach. Toward this end, successful development predictive mathematical model would represent significant advance for prevention efforts. Method: A deterministic, compartmental was developed, incorporating three processes: (1) individual factors, (2)...

We give a definition of net reproductive number R 0 for periodic matrix models the type used to describe dynamics structured population with parameters. The is based on familiar method studying map by means its (period-length) composite. This composite has an additive decomposition that permits generalization Cushing–Zhou in autonomous case. value determines whether goes extinct (R 0<1) or persists 0>1). discuss biological interpretation this and derive formulas two cases: scalar maps...

Hyla cinerea (Green Treefrog) is a common wetlands species in the southeastern US. To better understand its population dynamics, we followed relatively isolated of Green Treefrogs from June 2004 through October at federal office complex Lafayette, LA. Weekly, were caught, measured, marked with VIE tags, and released. The data used to estimate size. time frame was split into two periods: before after August 17, 2004. Before 2004, average estimated size 143, 24, 2005, this value jumped 446, an...