Approaches to Modeling Population Viability in Plants: An Overview

Population modeling, and especially the concept of population viability analysis (PVA), has played a fundamental role in the development of conservation biology as a discipline (Chap. 1, this Vol.). Early applications of PVA largely focused on the use of demographic models to identify minimum viable population sizes, but the term has since broadened to encompass a much wider range of approaches (Beissinger and Westphal 1998; Chaps. 6,9, this Vol.). Typically, PVA involves the development of models to address questions about the extinction risks facing one or more populations or to explore the factors influencing population persistence. What role PVA can or should play in conservation and management is a question that continues to stimulate a great deal of debate. Some authors argue that PVA is an effective and important conservation tool (Schemske et al. 1994; Brook et al. 2000), while others caution that PVA methods can be easily misused or may provide unreliable guidance to managers (Beissinger and Westphal 1998). In spite of this debate, there is no question that both the number of PVA approaches available to practitioners and their application to conservation problems is growing rapidly.