The demography and dynamics of heterogeneous populations


Predicting how the abundance of populations of plants and animals will change through time depends on recognizing differences among individuals, e.g., young vs. old, mature vs. immature, and on how those differences affect individual survival, growth, development, and reproduction, collectively known as the vital rates. Mathematical models based on these vital rates play an important role in both basic and applied population ecology. For example, they can measure the impact of environmental factors on population dynamics, evaluate strategies for the management of natural resources, and project the consequences of global change on species abundance.

However, in addition to obvious differences among individuals, all populations contain some level of heterogeneity among individuals that cannot be measured. This heterogeneity may result from physiological processes driven by food availability, genetic variation, individual history, or environmental effects. Hal Caswell and Mike Neubert will develop new mathematical models that include such types of heterogeneity. The population demographic models will be analyzed to quantify the effects of heterogeneity on population growth and sensitivity patterns, and  Stéphanie Jenouvrier will apply these latest development to understand if heterogeneity among snow petrel individuals will affect the population response to climate change.

This project is funded by NSF- Division of Environmental Biology and led by Hal Caswell.

Collaborators:  Hal Caswell, Mike Neubert and Henri Weimerskirch.

Pictures of snow petrels breeding in Terre Adélie, Antarctica