Ability of matrix models to explain the past and predict the future of plant populations.

Published

Journal Article

Uncertainty associated with ecological forecasts has long been recognized, but forecast accuracy is rarely quantified. We evaluated how well data on 82 populations of 20 species of plants spanning 3 continents explained and predicted plant population dynamics. We parameterized stage-based matrix models with demographic data from individually marked plants and determined how well these models forecast population sizes observed at least 5 years into the future. Simple demographic models forecasted population dynamics poorly; only 40% of observed population sizes fell within our forecasts' 95% confidence limits. However, these models explained population dynamics during the years in which data were collected; observed changes in population size during the data-collection period were strongly positively correlated with population growth rate. Thus, these models are at least a sound way to quantify population status. Poor forecasts were not associated with the number of individual plants or years of data. We tested whether vital rates were density dependent and found both positive and negative density dependence. However, density dependence was not associated with forecast error. Forecast error was significantly associated with environmental differences between the data collection and forecast periods. To forecast population fates, more detailed models, such as those that project how environments are likely to change and how these changes will affect population dynamics, may be needed. Such detailed models are not always feasible. Thus, it may be wiser to make risk-averse decisions than to expect precise forecasts from models.

Full Text

Duke Authors

Cited Authors

  • Crone, EE; Ellis, MM; Morris, WF; Stanley, A; Bell, T; Bierzychudek, P; Ehrlén, J; Kaye, TN; Knight, TM; Lesica, P; Oostermeijer, G; Quintana-Ascencio, PF; Ticktin, T; Valverde, T; Williams, JL; Doak, DF; Ganesan, R; McEachern, K; Thorpe, AS; Menges, ES

Published Date

  • October 2013

Published In

Volume / Issue

  • 27 / 5

Start / End Page

  • 968 - 978

PubMed ID

  • 23565966

Pubmed Central ID

  • 23565966

Electronic International Standard Serial Number (EISSN)

  • 1523-1739

International Standard Serial Number (ISSN)

  • 0888-8892

Digital Object Identifier (DOI)

  • 10.1111/cobi.12049

Language

  • eng