Sustainable yields that are at least 80% of the maximum sustainable yield are sometimes referred to as pretty good yield (PGY). The range of PGY harvesting strategies is generally broad and thus leaves room to account for additional objectives besides high yield. Here, we analyze stage-dependent harvesting strategies that realize PGY with conservation as a second objective. We show that (1) PGY...

This paper analyzes the stability of a coexistence equilibrium point of a model for competition between two stage-structured populations. In this model, for each population, competition for resources may affect any one of the following population parameters: reproduction, juvenile survival, maturation rate, or adult survival. The results show that the competitive strength of a population is aff...

We extend results of Gouzé and Hadeler (in Nonlinear World 1:23-34, 1994) concerning the dynamics generated by a map on an ordered metric space that can be decomposed into increasing and decreasing parts. Our main results provide sufficient conditions for the existence of a globally asymptotically stable fixed point for the map. Applications to discrete-time, stage-structured population models ...

Invasive species have disrupted ecosystems worldwide threatening native populations that are often ill equipped to out compete them. The interaction between invasive and native populations can be complicated by varying intensities of competition at different life stages. In this study, we analyzed competition of two stage-structured populations. The model takes the form of two Lefkovitch matrix...

This chapter, originally intended for inclusion in [4], focuses on modeling issues by way of an example of a predator-prey model where the predator has a juvenile stage. A careful derivation of the model is given starting from an age-structured model for the predator population. The method of characteristics is used to reduce the partial differential equations to a system of integro-differentia...

Patch occupancy models are extremely important and popular tools for understanding the dynamics, and predicting the persistence, of spatially structured populations. Typically this endeavor is facilitated either by models from classic metapopulation theory focused on spatially explicit, dispersal-driven colonization–extinction dynamics and generally assuming perfect detection, or by more recent...

In a recent work (Shao et al., 2009), a nonconsensus opinion (NCO) model was proposed, where two opinions can stably coexist by forming clusters of agents holding the same opinion. The NCO model on lattices and several complex networks displays a phase transition behavior, which is characterized by a large spanning cluster of nodes holding the same opinion appears when the initial fraction of n...