Using scalar models for precautionary assessments of threatened species

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dc.contributor.authorBridges, Todd S
dc.contributor.authorAkcakaya, H. Resit
dc.contributor.authorDunham, Amy E.
dc.date.accessioned2008-09-16T21:50:55Z
dc.date.available2008-09-16T21:50:55Z
dc.date.issued2006-10
dc.description.abstractScalar population models, commonly referred to as count-based models, are based on time-series data of population sizes and may be useful for screening-level ecological risk assessments when data for more complex models are not available. Appropriate use of such models for management purposes, however, requires understanding inherent biases that may exist in these models. Through a series of simulations, which compared predictions of risk of decline of scalar and matrix-based models, we examined whether discrepancies may arise from different dynamics displayed due to age structure and generation time. We also examined scalar and matrix-based population models of 18 real populations for potential patterns of bias in population viability estimates. In the simulation study, precautionary bias (i.e., overestimating risks of decline) of scalar models increased as a function of generation time. Models of real populations showed poor fit between scalar and matrix-based models, with scalar models predicting significantly higher risks of decline on average. The strength of this bias was not correlated with generation time, suggesting that additional sources of bias may be masking this relationship. Scalar models can be useful for screening-level assessments, which should in general be precautionary, but the potential shortfalls of these models should be considered before using them as a basis for management decisions.
dc.description.sponsorshipHazard/Risk Focus Area of the Army’s Environmental Quality Technology research program NSF
dc.identifier.citationBridges, Todd S, Akcakaya, H. Resit and Dunham, Amy E.. "Using scalar models for precautionary assessments of threatened species." (2006) Blackwell Publishing: <a href="https://hdl.handle.net/1911/21695">https://hdl.handle.net/1911/21695</a>.
dc.identifier.urihttps://hdl.handle.net/1911/21695
dc.language.isoeng
dc.publisherBlackwell Publishing
dc.subjectpopulation viability analysis
dc.subjectthreatened species
dc.subjectmatrix models
dc.subjectextinction risk
dc.subjectcount-based PVA
dc.subjectage structure
dc.titleUsing scalar models for precautionary assessments of threatened species
dc.typeJournal article
dc.type.dcmiText
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