The Berks-Mont News (

Bioeradication: Controling non-native invasive species 1/7

By Richard Gardner, Columnist

Thursday, July 18, 2013

This is an extension of a pair of presentations I gave at the NENHC 2013 in April of this year on the control of non-native invasive species. The first paper was on Bioeradication, with examples. The second was a presentation of Ailanthus altissima chemical control and bioeradication.
As in all things biological and especially ecological, it is not complete due to the complexity of biological systems and even greater complexity of ecological systems. The ideas and examples are still a work in progress. However, as is self-evident, what is presented here describes and explains the much safer use of Native Bioeradicants as an alternative to the dangerous practice of Classical Biocontrol.
Classical biocontrol – the introduction of non-native organisms in the attempt to reduce the effects of other introduced non-native organisms on ecosystems. This is a losing proposition as the goal is not to remove the problems, just reduce their effects. At the same time there are unforeseen negative effects which cannot be predicted in the local and extra-local ecosystems in which they are introduced through genetic or behavioral changes in native organisms in the ecosystem and in the non-native biocontrol such as the non-native biocontrol changing food sources to native organisms, acting as a food subsidy for native organisms which unbalances the native food web with multiple possible consequences, competition for nesting sites, breeding resources or any other resource with which it is in competition with native organisms, introduction of disease(s) to native organisms which may cause their extinction, … . Introducing the non-native invasive induced genetic and behavioral changes in native organisms. Therefore introducing another non-native to try to correct the prior problem will also induce genetic and behavioral changes in the native organisms.
Bioeradication – The extinction of a non-native (invasive) species from an ecosystem using native organisms. This is a winning proposition as the goal is the regeneration of the ecosystem by eliminating the non-native problem from the ecosystem using native organisms which minimizes the potential problems associated with the addition of non-native organisms as potential controls.
Enemy Release Hypothesis (ERH) – Immediately when removed from its home ecosystem an organism takes only a small fraction of its biocontrols (and competitors) with it. During transport and when introduced into a new ecosystem other biocontrols (and competitors) drop out, further reducing the number of control organisms. It is the disease/pest/competitor version of the Founder Effect in which a small segment of a population immigrates to a new location, taking only a small subset of the original population’s genes with it. As in the Founder Effect, individuals (control organisms and competitors) may continue to drop out due to random chance or environmental unsuitability, while others adapt to the new conditions with unpredictable consequences. The final effect is the elimination of many of the restraints which prevented the non-native organism from taking over its home ecosystem.
This frees the non-native from many of its health and competition issues and allows it to focus on growth and reproduction in the new ecosystem. This is one of the major reasons that an invader can out-compete natives. Natives are kept in balance with the rest of the ecosystem due to direct and indirect native competitors and native organisms that use the native as an energy source.
Richard Gardner lives in Upper Bern Township. His passions are ecology and history because with these we are able to understand our world, our place in it and our future.