PLoS ONE (Jan 2016)

Potential Impact of Carry-Over Effects in the Dynamics and Management of Seasonal Populations.

  • Eduardo Liz,
  • Alfonso Ruiz-Herrera

DOI
https://doi.org/10.1371/journal.pone.0155579
Journal volume & issue
Vol. 11, no. 5
p. e0155579

Abstract

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For many species living in changing environments, processes during one season influence vital rates in a subsequent season in the same annual cycle. The interplay between these carry-over effects between seasons and other density-dependent events can have a strong influence on population size and variability. We carry out a theoretical study of a discrete semelparous population model with an annual cycle divided into a breeding and a non-breeding season; the model assumes carry-over effects coming from the non-breeding period and affecting breeding performance through a density-dependent adjustment of the growth rate parameter. We analyze the influence of carry-over effects on population size, focusing on two important aspects: compensatory mortality and population variability. To understand the potential consequences of carry-over effects for management, we have introduced constant effort harvesting in the model. Our results show that carry-over effects may induce dramatic changes in population stability as harvesting pressure is increased, but these changes strongly depend on whether harvesting occurs prior to reproduction or after it.