POPULATION ECOLOGICAL MODELS

Chaos and population disappearances in simple ecological models.

A class of truncated unimodal discrete-time single species models for which low or high densities result in extinction in the following generation are considered. A classification of the dynamics of these maps into five types is proven: (i) extinction in finite time for all initial densities, (ii) semistability in which all orbits tend toward the origin or a semistable fixed point, (iii) bistab...

Ecological and Socio-ecological Economic Models

Integrating Urban Ecological Models

Over the past 20 years, understanding of the functioning of urban ecosystems has increased to the point where fairly sophisticated models of various subsystems have been developed by scientists working for federal, state, and local agencies, often in cooperation with university researchers. Each is designed to collect data and explore a specific urban/environmental system for issues related to ...

Partially Specified Ecological Models

Models are useful when they are compared with data. Whether this comparison should be qualitative or quantitative depends on circumstances, but in many cases some statistical comparison of model and data is useful and enhances objectivity. Unfortunately, ecological dynamic models tend to contain assumptions and simplifications which enhance tractability, promote insight, but spoil model fit and...

Diffusion Approximations for Ecological Models

Diffusion models are widely used in ecology, and in more general population biology contexts, for predicting population-size distributions and extinction times. They are often used because they are particularly simple to analyse and give rise to explicit formulae for most of the quantities of interest. However, whilst diffusion models are ubiquitous in the literature on population models, their...