Linking Landscape and Metapopulation Models

SOFTWARE FOR EVALUATING THE IMPACT OF FOREST MANAGEMENT PLANS ON WILDLIFE

Funded by Department of Agriculture 

P.I: H. Resit Akçakaya

In this project, we integrated the landscape model LANDIS with the metapopulation model RAMAS, and created a software tool for evaluating the viability of an endangered species under alternative forest management and conservation options. LANDIS predicts changes in the forest stand structure, including species composition, dominant tree species, and age distribution. RAMAS simulates the dynamics of species that inhabit distinct habitat patches. Both models are flexible, i.e., they can be (and have been) easily customized by the users to apply to different landscapes and species. The software we developed combines the features of both, and is applicable to multiple systems. This effort has resulted in a prototype program that was sent to several investigators for testing, was used in the case studies, and was demonstrated at several professional meetings.

The software we developed in this project represents the first attempt at establishing a spatially explicit link between the landscape and the metapopulation approaches, allowing an analysis of population viability based on landscape dynamics brought about by natural and human mediated processes such as succession, disturbances, and silviculture. In addition, the integration of two generic, spatially explicit models will allow application of this approach to other cases of species living in fragmented and dynamic habitats. The most important challenge to the practical use of this approach in conservation and management of species in dynamic landscapes would come from obtaining sufficiently precise estimates of model parameters. Future developments focusing on statistical methods of data analysis and parameter estimation would greatly enhance the usefulness of this approach.

The software tool we are developing in this project will be used by forest managers to assess the affect of changes in the landscape on the threatened and endangered species. Such landscape changes include natural disturbances such as fire and windthrow, as well as human-mediated changes such as timber harvest. The software integrates two modeling approaches to achieve its goal of allowing planners and managers to explore the viability of an endangered species under alternative forest management and conservation options. The first model is a landscape model, which predicts changes in the forest structure (age and species composition) in 10-year time steps. The second is a metapopulation model that estimates the extinction risk of the species, by simulating their dynamics in the changing habitat predicted by the landscape model. The integration of these two well-developed and widely used approaches to modeling will enable more realistic evaluation of schedule and type of timber harvest from the point of view of threatened and endangered species in the landscape.

The software developed in this study has been implemented as RAMAS Landscape.

RAMAS Landscape has recently been applied to evaluating the effect of timber harvest regimes on the viability of the Sharp-tailed Grouse in Wisconsin and the effect of altered fire regimes on the viability of Bell's Sage Sparrow in California.

See also: Akçakaya, H.R. 2001. Linking population-level risk assessment with landscape and habitat models. Science of the Total Environment 274:283-291.