Environmental impact modelling
Barlow N.D. (1999).
Models in biological control: a field guide
Pp. 43-70 In: Theoretical approaches to biological control, B.A. Hawkins and H.V. Cornell (Ed.) Cambridge University Press UK.
This paper reviews a number of examples of models for biological control programmes, but notes that the same principles can be applied to non-target as wellas target species.
Barlow N.D., Barratt B.I.P., Ferguson C.M. and Barron M.C. (2004).
Using models to estimate parasitoid impacts on non-target host abundance.
Environmental Entomology 33: 941-948.
A method is described for estimating the impact of a parasitoid on the abundance of a nontarget host, using the intrinsic rate of host increase, the average abundance of the host in the presence of parasitism, and the estimated mortality caused by the parasitoid. The method is applied to the braconid Microctonus aethiopoides Loan, which is known to attack native weevils. The non-target host population was modelled using discrete Ricker or continuous logistic models, tuning the models to host population data in the presence of parasitism, then removing parasitism and determining the increase in predicted equilibrium host density. In an area where up to 30% parasitism of a nontarget host population has been recorded, the model estimated an 8% reduction of the nontarget host, but in another area, where the parasitoid has not established, the method was applied in reverse to predict the parasitoid's impact if it did establish. In this case, the model predicted a 30% suppression of population density, the host's intrinsic rate of increase, rm, accounting for this difference in predicted impact.
Carvalheiro L.G., Buckley Y.M., Ventim R. and Memmott J. (2008).
Assessing indirect impacts of biological control agents on native biodiversity: a community-level approach.
Pp. 83-86 In: Proceedings of the XII International Symposium on Biological Control of Weeds, (Ed.) La Grande Motte, France, 22-27 April, 2007.
Apparent competition (competition due to shared natural enemies) has been neglected when considering possible impacts of biological control agents because of the difficulty in assessing and predicting indirect effects. In this paper the authors outline a methodology to predict and measure non-target impacts of biological control agents due to apparent competition.
Chalak M., Hemerik L., van der Werf W., Ruijs A. and van Ierland E.C. (2010). On the risk of extinction of a wild plant species through spillover of a biological control agent: analysis of an ecosystem compartment model. Ecological Modelling 221: 1934-1943
Holt R.D. and Hochberg M.E. (2001). Indirect interactions, community modules and biological control: a theoretical perspective. Pp. 13-37 In: Evaluating indirect ecological effects of biological control, E. Wajnberg, J. K. Scott and P. C. Quimby (Ed.) CABI Publishing, Wallingford, Oxon., UK
Johnson M.T., Follett P.A., Taylor A.D. and Jones V.P. (2005).
Impacts of biological control and invasive species on a non-target native Hawaiian insect.
Oecologia 142: 529-540.
Adverse impacts on endemic Hawaiian koa bug, Coleotichus blackburniae White (Hemiptera: Scutelleridae), by parasitoids introduced for control of the southern green stink bug, Nezara viridula (L.) (Hemiptera: Pentatomidae) were examined using life tables. Self-introduced generalist egg predators, had the greatest impacts on C. blackburniae populations. Effects of intentionally introduced parasitoids were relatively minor, although the tachinid T. pilipes showed potential for large impacts at individual sites. In retrospect, non-target attacks by biological control agents on C. blackburniae were predictable, but not the environmental range and magnitude of impacts.
Lynch L.D. and Ives A.R. (1999).
The use of population models in informing non-target risk assessment in biocontrol.
Aspects of Applied Biology 53: 181-188.
The use of models to illustrate risks of biological control to nontarget organisms is shown using two examples. The first model for classical biological control illustrates how the minimum density observed in the nontarget species follows a simple approximation, which is based on the carrying capacity for the target and the searching efficiency of the agent for the nontarget host. The second model looks at how augmentation methods of biocontrol may have impacts on the density of non-target.
Murdoch W.W., Briggs C.J. and Nisbet R.M. (1996).
Competitive displacement and biological control in parasitoids: A model.
American Naturalist 148: 807-826.
California red scale is controlled in many areas by parasitoids of the genus Aphytis. In southern California, Aphytis lingnanensis provided inadequate control of red scale in inland valleys. Aphytis melinus was introduced, competitively displaced A. lingnanensis within a few red scale generations, and caused satisfactory biological control. Aphytis melinus is successful on smaller- sized scale than A. lingnanensis, and a stage-structured parasitoid-host model is presented in which the two parasitoid species are the same except for A. melinus's size-dependent advantage in sex allocation. This model can account for the competitive displacement of A. lingnanensis and the improvement in biological control. Aphytis melinus can also produce an additional female egg from larger red scale, and this increases its advantage in competition. The effects of other model parameters were discussed along with implications for a predictive theory of biological control.
Parker I.M., Simberloff D., Lonsdale W.M., Goodell K., Wonham M., Kareiva P.M., Williamson M.H., Von Holle B., Moyle P.B., Byers J.E. and Goldwasser L. (1999). Impact: toward a framework for understanding the ecological effects of invaders. Biological Invasions 1: 3-19.
Host range expansion/evolution