Bioeradication versus Biocontrol, definitions, theory and practice. This is a preliminary theoretical discussion of the use of native organisms to eradicate non-native invasive organisms from ecosystems as opposed to using non-natives to attempt control of other non-natives.

1. Bioeradication

2. Richard Gardner
rtgardner3@yahoo.com
June 19, 2013

3. 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.

4. 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.

5. 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.

6. 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.

7. Evolution of Increased Competitive Ability (EICA) – This starts on at the beginning of the
introduction to a new ecosystem. It is most strongly seen on the front end or beginning of
the Gaussian curve of an invasion. It is the genetic shakeout where genes and genotypes
that are unfit for the new ecosystem go extinct. At the same time, genes and genotypes
that increase the fitness/invasiveness of an invader increase or develop and proliferate.
This is parallel to the Founder Effect in populations. The beginning is at removal from the
original ecosystem and transport to the new ecosystem as even this requires special
adaptations. However, it most strongly develops from the moment of introduction to the
new ecosystem and through the early stages of logarithmic expansion. The process
continues throughout its residency in the new ecosystem until it becomes extinct by a
native (system) which evolves to drive it extinct through competition, herbivory, disease or
any of numerous other processes alone or more likely as part of or in cooperation with
other processes.

8. Bioeradicant – Any native organism in any time frame from seconds to centuries that partially or
fully inhibits a non-native organism and helps to drive it to extinction. Unfortunately this is not
the goal of using non-native biocontrols on non-native invasives. They are looking for control,
not extinction of both of the introduced species (control and invasive) and groups of species.
Bioeradicant system – A group of native organisms which through any biological relationship
and time frame partially or fully inhibits a non-native organism to the point it is driven to
extinction.

9. Direct bioeradication – This is the use of a native organism or native organism system as a
bioeradicant for a specific organism. In the case of Ailanthus altissima it may be introducing a
native wilt pathogen such as Fusarium oxysporum or Verticillium dahliae to work with Aculops
ailanthii and Atteva aurea.
Indirect bioeradication – Providing the native resources such as food, breeding sites or shelter
needed for a native bioeradicant or bioeradicant system to develop at a specific location for a
specific organism. This may be nectar sources, sheltering plants, mutualistic fungi, water source
or … .

10. Bioeradication garden – A form of Indirect Bioeradication which is a garden of local native
plants that provide a resource at any life stage that a native bioeradicant needs to be effective as
a bioeradicant such as food, egg laying sites, overwintering sites, protection from predators, …,
Bioremediation can be a direct result of using a bioeradication garden by providing native
organisms to replace the extinct non-native organisms.
Bioeradication resource – Any naturally occurring environmental resource a native bioeradicant
needs to be effective as a bioeradicant.

11. Resource use – This is the use by a native bioeradicant of a native or non-native resource. In the
case of a non-native resource it takes time to adapt to using it through either learning to use it
(behavioral changes) or genetic changes, often both.
Resource familiarity – This is the amount of use of a resource by a native bioeradicant. In the
case of non-native (invasive) resources it requires time for a native bioeradicant to adapt to it
through either behavioral or genetic changes and begin driving the non-native to extinction.
Resource heritage – This is the passing on of a behavioral and/or genetic adaptation to a
resource by a native bioeradicant. This can be through learning, by genetic change or more
probably a combination of both. It can spread through a species horizontally as one organism
learns from another or vertically as it is passed on to/through offspring through learning or
genes.

12. Mutualism – Two or more organisms which cooperate to the benefit of each other. Bioeradicant
systems reflect this at different levels of relationship by eliminating a non-native from the
ecosystem through (unintended) cooperation, different feeding strategies which enhance the
success of both species, behavioral adaptations or other strategies.
Competition – Relationships where certain organisms benefit through a variety of mechanisms
to the detriment of others without necessarily using them as an energy source. This is an
essential element in bioeradication.
Herbivory, predation and parasitism – Relationships in which one organism or groups of
organisms benefit by using other organisms as an energy source. This does not imply that all
the benefit accrues to the herbivore, predator or parasite as there are often unseen benefits to
both organisms.

13. Direct competition – When an organism competes directly with another organism for a
resource. Examples are two species of bees competing for a pollen source or a vulture and a
crow competing for an animal carcass. This is good if a native bioeradicant is successfully
competing with a non-native organism and driving it to extinction. It is bad when a non-native is
driving a native to extinction.
Indirect competition – Positive is when an organism provides a resource needed for another
organism to compete with a native or non-native organism. Knowing how to manipulate this is
better than introducing a non-native organism into an ecosystem to control another non-native
organism. An example is providing plants as egg laying sites for a native butterfly that competes
with a non-native species such as the cabbage moth. Indirect Bioeradication can be a result of
this.
Negative is using a native organism to destroy a biological resource that a non-native organism
needs which is in competition with a native organism. This may be planting native wildflowers
in a meadow to remove a grass needed by a non-native moth such as food, egg laying sites or
shelter.

14. Resource enhancement/depletion – This is enhancing a resource needed by a native
bioeradicant to help it eradicate a non-native species. By changing the conditions in an
ecosystem, the competitors’ dominance and status in the ecosystem changes. This may be a
change in the humidity which changes the fungi associated with a competitor, either increasing
or reducing its ability to compete and function in an ecosystem. Or changing the conditions
needed by a native competitor on that competitor. It is similar to a domino effect except that it
is about changes on one component of an ecosystem causing changes on another organism
which affects that organism’s ability to survive and/or compete in that ecosystem. This is a
strategy which should be used carefully and with much forethought due to the very strong
possibility that by changing the abiotic environment, more damage than good can be done. The
same is true with the biological components of an ecosystem. One change can cascade
uncontrollably in an unforeseen direction which causes more harm than the original problem
did.
This may be as simple as removing a dam to allow fish to migrate along a river corridor, adding
stepping stones in a creek to facilitate drinking by native animals or changing a meadow back to
a flooded meadow to remove burrow sites.

15. Bioremediation – the use of native organisms to displace or replace non-native organisms as
they are eliminated from an ecosystem. This is an expansion of the traditional definition of
bioremediation into an ecological usage beyond the microbial level. Whereas, traditional
bioremediation is the use of microorganisms to mitigate chemical or organic pollution, this is the
use of the term to mean use of native organisms to restore an ecosystem during and after the
removal of a non-native organism or non-native organism system.
The use of Indirect Bioeradication is one inherent way of doing this as it places native species
which already have a place in the ecosystem back into the natural succession process. This fills
the ecosystem’s temporal and spatial gaps left by the eradication of the non-native species. This
in turn prevents reinvasion by non-native species.

16. In Bioeradication we are trying to understand all the relationships within an ecosystem to find
native organisms to hinder and eradicate non-native organisms. We are looking more for
systems composed of many organisms than single organisms or “magic bullets” as systems are
more stable due to their complexity and composed of multiple strategies for destroying non-
native invasives. Therefore, bioeradication systems are more able to adapt to changing
environmental conditions, the changing gene structure and the changing strategies used by an
invasive non-native.

17. Adaptation of Novel Weapons or their development is a major component of EICA in the
ongoing and continual changes of adaptation to changing ecosystem conditions by non-native
species. Bioeradicants are able to neutralize the Novel Weapons by being immune to their
effects due to experience with natives using the same or similar “weapons”, adapting present
defenses or by developing new defenses. The more native congeners or confamiliars of the
invasive the native bioeradicant uses, the more apt it is to have the genetic and/or behavioral
tools to pace with and out pace the changes in the non-native. Therefore, also the larger the
number of congeners and confamiliars in an ecosystem, the greater the chance a
bioeradicant/bioeradicant system will develop. This is due to potential bioeradicants being
adapted to the defenses of native congeners or confamiliars and having been potentially
exposed to similar “weapons” or the genes responsible for them. Thus the defenses, the ability
to adapt already in place defenses or the ability to develop new defenses to Novel Weapons is
already in place in bioeradicants. The result is either the non-native is outcompeted by the
bioeradicant or the non-native is used as an energy source by the bioeradicant. Most probably
it is a combination of both that will be most effective.

18. ERH and EICA are continuing processes throughout the residency on non-natives in the new
ecosystem, including failed introductions. The evolution of bioeradicants begins at the moment
of introduction of the non-native. After the non-native is eradicated, the native bioeradicants
remain in the system with genes and physical/chemical structures already in place should the
non-native or a relative try to reenter the ecosystem. This allows the native bioeradicants to
swiftly deal with new attempts of invasion by the non-native or its close relatives.
Bioeradication starts being effective when native bioeradicants evolve beyond the effects of ERH
and faster than EICA can keep pace with the evolving new defenses and adaptations of native
organisms and the changing conditions which cause them to either use the non-native as an
energy source or out-compete it for an essential resource.
The EICA/Bioeradicant process is a continuing process until the non-native goes extinct in the
invaded ecosystem.

19. Combined, EICA and ERH explain the first parts of an invasion, up into the logarithmic growth.
What they do not explain is the evolution of native organisms into bioeradicants and
bioeradicant systems when population densities begin to level and crash at similar rate as their
increase in the ecosystem. When plotted, this will be similar to a bell curve or Gaussian
distribution as natives adapt to the non-natives and drive them to extinction by outcompeting
with them for resources or by the non-native becoming an energy source for the bioeradicant.
The highest probability is that a bioeradicant system develops which contains multiple
organisms using multiple strategies which outcompete the non-native for a critical resource(s)
and/or use it as an energy source. That this will be a system means that it will be slower to form
and become obvious due to the increased complexity as compared to a biocontrol or a
bioeradicant, even though individual components will develop at different rates and become
apparent at different times, seasonal and temporal.

20. There is a critical point in time or critical population density of the non-native needed for a
bioeradicant/a bioeradicant system to develop and target the non-native. Once this point is
reached there will be decreases in the population size and density of the non-native in line with
a Gaussian curve, i.e. a temporary continuation of the increase in population size of the non-
native followed by a plateau or peak and then a decrease as the effects of the bioeradicant
(system) begins to take effect. The more native congeners and confamiliars of the non-native
and its biocontrols, the potentially lower the critical point will be on the curve both in time and
the population density of the non-native. There is also a spatial component in that the closer
spaced members of the non-native are, the easier it is to spread genes, behavioral patterns and
members of the bioeradicant (system) to other individuals in the non-native population. In
other words, critical densities may be the overall population size of a non-native organism in an
ecosystem along with the population density of organisms in a set area and the density of the
potential bioeradicants. This is seen with Lonicera morrowii, Rosa multiflora and Ailanthus
altissima. All three invasives not only have a high density of individuals in an ecosystem, but
have dense stands of individuals. Thus the spread of the bioeradicants, their genes and
behaviors are doubly enhanced due to stand density and the overall density of the invasive in an
ecosystem.

21. The biggest question asked about bioeradication is why it has not been seen and recorded? The
answer is threefold. The first reason is that we are not looking for it. Second, bioeradication
may happen before we are aware of a problem it took to extinction. Third, is that this may take
many years to hundreds of years to happen. In essence, the process of bioeradication may
happen too fast to be noticed. Or, it may happen too slowly to be noticed by a researcher or
school of researchers.

22. The most important part of what is being presented is that it is not complicated. Humans have
the horrid ability to complicate the simple and obvious. They also have the destructive desire
and ability to tinker. After they are done tinkering, bad data is gathered and called good
because the numbers meet certain parameters. Whereas, if the tinkering was not done in the
first place, there is no need to tinker again and the data gathered is actually good. A prime
example of the tinkering mindset is seen in my health issues – diabetes and bipolar II. For
diabetes, instead of eating healthy, avoiding toxic chemical rich foods and exercising,
medications are prescribed, artificial sweeteners are suggested and a whole industry is
developed that would not be necessary if we did not tinker with the foods in the first place and
went out for a walk every day. The same is true with bipolar II. Instead of dealing holistically
with the condition, we are fed medications until we are insensate and celebrate because we
have “controlled” it. We do the same with ecological systems, tinker until it breaks and then
tinker again to try to fix it. Then celebrate our apparent successes.

23. Finally, biology and ecology are tremendously complex. Reducing phenomena down to one or
two rules or variables is unrealistic. As scientists, we search for absolute and straightforward
answers in the simplest terms. Unfortunately, for every apparent absolute rule in biology and
ecology, there are many shades and variations. What is written here is an outline in the
broadest sense of what happens in an ecosystem, not finitely detailed descriptions with all the
variables. For instance, with Ailanthus altissima, the herbivorous insects which feed on it and
the pathogenic fungi which infect it require different conditions to flourish. What is true in a
field is not necessarily true on the edge of a wetland where there is more available water. Low
moisture favors the herbivorous insects. Higher moisture favors the pathogenic fungi. Both sets
of organism are present in both situations. However, the effects of each organism differ in the
different conditions, even though the combination is often fatal in both situations to Ailanthus
altissima.

24. Constructive input is asked for so this concept can be strengthened and safer practices
developed than are presently used.

25. The Slideshare.net presentations are at:
http://www.slideshare.net/hacuthbert/gardner-biocontrol-nenhc-2013
http://www.slideshare.net/hacuthbert/gardner-ailanthus-nenhc-2013

26. Now it is time for me to take a walk in the woods.

27. Richard Gardner
rtgardner3@yahoo.com
June 19, 2013