Implications of different population model structures for management of threatened plants.
Population viability analysis (PVA) is a reliable tool for ranking management options for a range of species despite parameter uncertainty. No one has yet investigated whether this holds true for model uncertainty for species with complex life histories and for responses to multiple threats. We tested whether a range of model structures yielded similar rankings of management and threat scenarios for 2 plant species with complex postfire responses. We examined 2 contrasting species from different plant functional types: an obligate seeding shrub and a facultative resprouting shrub. We exposed each to altered fire regimes and an additional, species-specific threat. Long-term demographic data sets were used to construct an individual-based model (IBM), a complex stage-based model, and a simple matrix model that subsumes all life stages into 2 or 3 stages. Agreement across models was good under some scenarios and poor under others. Results from the simple and complex matrix models were more similar to each other than to the IBM. Results were robust across models when dominant threats are considered but were less so for smaller effects. Robustness also broke down as the scenarios deviated from baseline conditions, likely the result of a number of factors related to the complexity of the species' life history and how it was represented in a model. Although PVA can be an invaluable tool for integrating data and understanding species' responses to threats and management strategies, this is best achieved in the context of decision support for adaptive management alongside multiple lines of evidence and expert critique of model construction and output.
Biology Department, University of California Riverside, 900 University Avenue, Riverside, CA, 92521, U.S.A.
Helen M
HM
Regan
Biology Department, University of California Riverside, 900 University Avenue, Riverside, CA, 92521, U.S.A.|Biology Department, Universidad Nacional de Colombia, Carrera 45 #26-85, Edif. Uriel Gutiérrez, Bogotá D.C., Colombia.
Clara I
CI
Bohórquez
Centre for Ecosystem Science, School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia.|New South Wales Office of Environment & Heritage, P.O. Box A290, Sydney South, NSW, 1232, Australia.
David A
DA
Keith
Arthur Rylah Institute for Environmental Research, The Department of Environment, Land, Water and Planning, 123 Brown Street, Heidelberg, VIC, 3084, Australia.|School of Biosciences, University of Melbourne, Parkville Campus, VIC, 3010, Australia.
Tracey J
TJ
Regan
Biology Department, University of California Riverside, 900 University Avenue, Riverside, CA, 92521, U.S.A.
Kurt E
KE
Anderson
D003247:Conservation of Natural Resources; D056727:Endangered Species; D005390:Fires; D010944:Plants; D011157:Population Dynamics; D035501:Uncertainty
Grevillea caleyi; Xanthorrhoea resinosa; análisis de viabilidad poblacional; conservation management; incertidumbre de modelo; individual-based model; manejo de la conservación; matrix model; model uncertainty; modelo basado en el individuo; modelo matricial; population viability analysis