Potential of Branching Processes as a Modeling Tool for Conservation Biology

Conclusion

The canonical structure of BPs and the theoretical results available allow us to handle, within the same conceptual framework, PVA models with a variety of demographic features. The reader interested in applying BPs structures and results to a specific PVA has the choice between developing his or her own model and using a generic extinction simulation tool (for a review of some of these models, see Lindenmayer et al. 1995). Among generic simulation tools, the latest version of the software ULM (Legendre and Clobert 1995) takes explicitly into account the theoretical results presented here.

Last, the tuning of a BP model to a specific population-environment system based on empirical data will meet problems of parameter estimation in small populations and of detection and assessment of a specific functional form of density dependence. These questions, which depend critically on the quality of the data available, are, however, not specific to BPs. Classically, the range of strategies thus spreads from a detailed PVA model, relying on extensive data (as in, e.g., Woolfenden and Fitzpatrick 1991), to a series of different scenarios corresponding to varying assumptions and parameter values, when data are not sufficient.

Deterministic theory in population ecology thus seems to be of little help in providing a framework for probability theory. We had better not adhere too much to our deterministic concepts and ideas, but start afresh. —J. Reddingius (1971)