Detecting density dependence in recovering seal populations
Journal article, 2011

Time series of abundance estimates are commonly used for analyses of population trends and possible shifts in growth rate. We investigate if trends in age composition can be used as an alternative to abundance estimates for detection of decelerated population growth. Both methods were tested under two forms of density dependence and different levels of environmental variation in simulated time series of growth in Baltic gray seals. Under logistic growth, decelerating growth could be statistically confirmed after 16 years based on population counts and 14 years based on age composition. When density dependence sets in first at larger population sizes, the age composition method performed dramatically better than population counts, and a decline could be detected after 4 years (versus 10 years). Consequently, age composition analysis provides a complementary method to detect density dependence, particularly in populations where density dependence sets in late.

Detecting population trends

Environmental stochasticity

Age-structured populations

Density-dependent population growth

Population management

Author

Carl Johan Svensson

University of Gothenburg

Anders Eriksson

Chalmers, Energy and Environment, Physical Resource Theory

Tero Harkonen

Naturhistoriska riksmuseet

Karin C. Harding

University of Gothenburg

Ambio

0044-7447 (ISSN) 16547209 (eISSN)

Vol. 40 1 52-59

Subject Categories

Ecology

DOI

10.1007/s13280-010-0091-7

More information

Created

10/7/2017