Consequences of asymmetric competition between resident and invasive defoliators: A novel empirically based modelling approach

Abstract

Invasive species can have profound effects on a resident community via indirect interactions among community members. While long periodic cycles in population dynamics can make the experimental observation of the indirect effects difficult, modelling the possible effects on an evolutionary tithe scale may provide the much needed information on the potential threats of the invasive species on the ecosystem. Using empirical data from a recent invasion in northernmost Fennoscandia, we applied adaptive dynamics theory and modelled the long term consequences of the invasion by the winter moth into the resident community. Specifically, we investigated the outcome of the observed short-term asymmetric preferences of generalist predators and specialist parasitoids on the long term population dynamics of the invasive winter moth and resident autumnal moth sharing these natural enemies. Our results indicate that coexistence after the invasion is possible. However, the outcome of the indirect interaction on the population dynamics of the moth species was variable and the dynamics might not be persistent on an evolutionary time scale. In addition, the indirect interactions between the two moth species via shared natural enemies were able to cause asynchrony in the population cycles corresponding to field observations from previous sympatric outbreak areas. Therefore, the invasion may cause drastic changes in the resident community, for example by prolonging outbreak periods of birch-feeding moths, increasing the average population densities of the moths or, alternatively, leading to extinction of the resident moth species or to equilibrium densities of the two, formerly cyclic, herbivores. (c) 2014 Elsevier Inc. All rights reserved.

Keywords

Adaptive dynamics; Branching-extinction cycle; Parasitism; Population cycles; Predation

Published in

Theoretical Population Biology
2014, volume: 92, pages: 107-117
Publisher: ACADEMIC PRESS INC ELSEVIER SCIENCE

SLU Authors

• Ammunét, Tea

  • Department of Ecology, Swedish University of Agricultural Sciences
    
  • University of Turku

UKÄ Subject classification

Ecology
Mathematical Analysis

Publication identifier

• DOI: https://doi.org/10.1016/j.tpb.2013.12.006

Permanent link to this page (URI)

https://res.slu.se/id/publ/64422