Population numbers count: Tools for near-term demographic analysis

Citation
Ga. Fox et J. Gurevitch, Population numbers count: Tools for near-term demographic analysis, AM NATURAL, 156(3), 2000, pp. 242-256
Citations number
31
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Environment/Ecology
Journal title
AMERICAN NATURALIST
ISSN journal
0003-0147 → ACNP
Volume
156
Issue
3
Year of publication
2000
Pages
242 - 256
Database
ISI
SICI code
0003-0147(200009)156:3<242:PNCTFN>2.0.ZU;2-#
Abstract
How do unit or proportional changes in vital rates affect populations in th e short term? We present a new extension to standard methods of matrix mode l analysis that allows us to answer this question for the first time. By us ing the sensitivities of all the eigenvalues/vectors, rather than just the leading eigenvalue/vector pair, we can predict the consequences of unit or proportional changes in vital rates to population size and structure at any arbitrary time, not just when populations have neared their stable distrib ution. These extensions are particularly important in studying populations subject to frequent disturbance, where stable growth rare and stable distri bution do not provide sufficient information about the effects of changes i n the vital rates; managed populations in which short-term goals are define d; and the adequacy of the underlying matrix model for either short- or lon g-term understanding. We use analysis of empirical data on the cactus Coryp hantha robbinsorum to demonstrate this approach and show that short-term pr edictions can differ substantially from those based on standard, asymptotic , analysis.