Locating and Using Native Biocontrols for Invasive

Non-native Plants, a New Paradigm.

ABSTRACT: The debate over using classical biocontrol to control invasive non-native organisms is redundant and stale. Instead of searching for new methods and

synergies, the debate is over the pros and cons of classical biocontrol. This presentation will offer

examples of native biocontrol systems. At the same time it will offer practical insights into finding native

biocontrols for non-native invasive plants. The goal of this presentation is to help end the continuing

unethical and scientifically flawed introduction and use of non-native organisms in hopes of controlling

other non-native organisms.

Richard Gardnerrtgardner3@yahoo.com

(410) 726-3045

Walk moreTinker less

Most issues in ecology can be understood by walking.

Therefore the most important trait of an ecologist – loving to walk.

Baseline philosophy

We are not the center of creation and its ultimate result.

Time is the most important character of biocontrol.

Human time is irrelevant.

Ecological/evolutionary time is the only relevant time.

What humans do wrong in human time takes ecological/evolutionary

time to fix.

The same human centered mistakes that caused the problems

cannot solve them.

Basic Concepts

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Native biocontrol

Non-native invasive

Native congeners of non-native invader

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The expected population curves for native biocontrol use. The baseline population for native organisms changes as the native biocontrols adapt to the non-native invasive and eat a few

more of the native while the system comes back into balance as the non-native is destroyed. There is some recoverable risk to the native ecosystem, but not the unrecoverable risk of

introducing non-native biocontrols.

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Non-native biocontrol

Non-native invasive

Native congeners of non-native invader

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Simplified expected curves for what happens when a non-native biocontrol is introduced after the establishment of a non-native invasive.

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Non-native biocontrols

Pioneer non-native invasive

Native congeners of non-native invasive

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Secondary non-native invasives

A more complex version of what happens when a (pioneer) non-native plant is introduced followed by its non-native biocontrol. The native system collapses allowing secondary non-

natives to enter.

Native organisms

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Non-native specialist biocontrol

Non-native invasive Chemical defenses of non-native invasive population

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This diagram demonstrates what happens when a non-native specialist biocontrol is reintroduced to its non-native host.

Basic terms:

Classical biocontrol – the use of non-native organisms in the attempt to minimize the effects of other non-

native organisms on ecosystems. This is a losing proposition as it does not attempt to remove the

problems, just minimize their effects.

Bioeradication – the extinction of a non-native invasive from an ecosystem using native biocontrols, the goal.

This is a winning proposition as it is the regeneration of the ecosystem by eliminating the problem from the

ecosystem using naturally available native organisms.

Biocontrol – any organism in any time frame from seconds to centuries that partially or fully inhibits a non-native organism. Usually the goal of using non-native biocontrols on non-native invasives. This is a

losing proposition.

Biocontrol system – a group of organisms which through any biological relationship partially or fully

inhibits a non-native organism.

Direct biocontrol – use of a native organism or system as a biocontrol for a specific organism.

Indirect biocontrol – providing the native resources such as food, breeding sites or shelter needed for a

native biocontrol or biocontrol system to develop for a specific organism.

Biocontrol garden – a garden of local native plants that provide a resource that a native biocontrol needs to be effective as a biocontrol such as food, egg laying sites, overwintering sites, protection from predators, …, in

any life stage.

Biocontrol resource – any local naturally occurring environmental resource a native biocontrol needs to be

effective as a biocontrol.

Resource familiarity – the amount of use of a resource by a native biocontrol. In the case of non-native resources

(invasive) it requires time for a native biocontrol to adapt to it through either behavioral or genetic changes.

Resource use – the use by a native biocontrol 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 heritage – the passing on of a social or genetic adaptation to a resource by a native biocontrol. 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.

Mutualism – two or more organisms which cooperate to the benefit of each other.

Commensalism – two or more organisms living together where at least one benefits and the effects on

other organisms are neutral.

Competition – relationships where certain organisms benefit through a variety of mechanisms to the

detriment of others without necessarily using them as an energy source.

Herbivory, predation and parasitism – relationships in which one organism or groups of organisms benefit by

using other organisms as an energy source.

In Biocontrol/Bioeradication we are trying to understand all these relationships within an ecosystem and use them to find native

organisms to hinder and eradicate non-native organisms.

Examples of apparent biocontrol systems and

potential biocontrol systems.

Ailanthus altissima, the system I know best.

bark herbivory by Atteva aurea larva

This photo shows herbivory, disease and the effects of A. ailanthii. A few meters away is a meadow of Solidago canadensis which was a

nectar source for A. aurea adults and probable mating site.

Rose rosette disease, the system I am getting to know.

Rosa multiflora, Multiflora Rose with rose rosette disease.

Other possible systems I see while walking.

fd

disease

herbivory

Loniera japonica, Japanese honeysuckle

Lonicera morrowii, Morrow’s honeysuckle

stressed leaves, the result of disease and/or herbivory

herbivory

Lonicera maacki, Amur honeysuckle

herbivory and disease?

Elaeagnus umbellata, Autumn Olive

• A family of plants with native congeners.• Birds move between stands carrying Aculops ailanthii mites with them.• Atteva aurea females pick up and move Aculops ailanthii between trees while laying eggs on various trees.• Atteva aurea carries disease ingested as a larva, incubated as a pupa and deposited as an adult on leaves while laying eggs.• Disease enters tree through the feeding wounds of Atteva aurea larvae on branches and leaves.• Disease is carried by the Aculops ailanthii.• Pollinators also carry Aculops ailanthii between trees.• Wind carries Aculops ailanthii between nearby trees.

Ailanthus altissima

• Large family of plants with native congeners from which diseases and herbivores can become biocontrols.

• Birds move between bushes carrying Phyllocoptes fructiphilus mites between them.• Rose rosette disease, an Emaravirus, is carried by Phyllocoptes fructiphilus.• Birds move mites between the bushes which they also nest in.• Pollinators carry mites between parts of the same bush and nearby bushes.• Pollinators also carry mites between bushes.• Wind carries the mites between nearby bushes.

Rosa multiflora:

• Large family of plants with native congeners. • Disease is carried by mites.• Deer carry mites in a way similar to ticks.• Deer browse on local vegetation as a source of food, use the shrubs for cover and move between stands of shrubs as they move between environmental resources.• Birds move mites between the shrubs in which they roost, nest and feed on the fruit.• Pollinators carry the mites between shrubs.• Wind carries the mites between nearby plants.

Lonicera morrowii: possible scenario

Most likely scenario for the movement of Aculops ailanthii and pathogens across landscapes

Birds – long distances searching for familiar shelter during migrations.- medium and short distances between nearby stands.

Atteva aurea – mostly medium and short distances between egg laying sites.Wind - short distances within stands and between close stands with high mite densities.

Probable scenario for the spread of rose rosette disease across the ecosystems.

Birds - long distances searching for food and shelter during migrations.- medium distances between nests and food sources.

- short distances as part of normal random movement. Pollinators - medium and short distances between food sources.Wind - short distances within stands and between close stands.

Deer - mostly within and between thickets in the short and medium distances.Birds - across long distances through migration, medium distances while searching for food and short distances while using the plants as shelter and nesting locations.

Pollinators - across medium and short distances while moving between flowers.Wind - across short distances primarily within thickets.

Possible scenario for the movement of biocontrol pathogens and insect herbivores between Lonicera morrowii plants.

The more native congeners the more apt the native biocontrol system is to

form and the more complexity possible.

As complexity increases so does the probability of a control system and the

more stable the system is.

Complexity may involve multiple food sources, multiple families of organisms which contribute to

control but do not directly control the target, multiple types of plant use (herbivory, pollination,

nesting and roosting sites, disease), multiple types of control organisms such as mammals, birds, insects, diseases and different feeding strategies (browsing,

grazing, nectarivory, frugivory, parasitism among others) .

Reintroducing a coevolved herbivore specialist to its

original host will fail.

By inference, this has been shown with wild parsnip,

Senecio jacobaea. (Zangerl, et al, 2005)

WhenTyria jacobaeae, one of its specialist biocontrols from

Europe was accidently reintroduced after at least 230

years,

the chemical defenses reasserted themselves.

In other words, the highest fitness level of the plant shifted

from its original chemical defenses to growth and

reproduction in the absence of a specialist herbivore as it

invaded a new ecosystem, i.e. enemy release.

When the herbivore was reintroduced, the highest fitness level shifted back towards using the original or similar chemical defenses at the cost of energy

expended for growth and reproduction.

Since the genes for the original chemical defenses were already

present, turning them on was easy.

It did not involve the much slower process of evolving defenses to a new threat.

The energy output shifted away from defense in the absence of

many of its specialist herbivores.

It then shifted back when the specific herbivore was

accidently introduced from Europe.

Since the chemical defense reversion was small because the threat was small, the plant

continues to thrive as an invasive.

Examples of catastrophic failures by introduced

biocontrols:

The moth Cactoblastis cactorum was introduced in the island of Nevis in Caribbean to control Opuntia monacantha (Willd.)

Haw. in 1957 (Pemberton, 1995).

Now it is spreading throughout the Caribbean eating native

congeners. It is only a matter of time before it reaches North American Opuntia species.

The weevil Rhinocyllus conicus was introduced to control Canada

thistle, Cirsium arvense. Instead it jumped to native thistles. This has

put several of them in danger of extinction.

Example of already present organisms controlling a non-

native:

Euhrychiopsis lecontei, a native North American weevilprefers the exotic aquatic plant

Eurasian watermilfoilMyriophyllum spicatum over

native watermilfoils.(Sallie P. Sheldon, Robert P. Creed, Jr, 2003)

This was expected as the non-native had no defenses to the

native generalist herbivore.

The key to finding a native biocontrol (system) is to find an

organism which a generalist (herbivore) that feeds broadly

on a family or genus and a specialist (herbivore) to that feeds only on that family or

genus.

This means that the biocontrol has a the genetic ability to

switch from one plant to another and yet will not cause the

extinction of coevolved food sources.

The necessary conditions for a biocontrol system:

• food sources for all organisms at all life stages• shelter for the various life stages• breeding sites and egg laying locations

1.) plant biocontrol garden of a wide variety of mostly Asteraceae seeds to determine which plants Atteva aurea uses as nectar sources.2.) culture and identify to family the diseases which affect Ailanthus.3.) walk a lot to continue finding and understanding native biocontrol systems.

Path forward/2013 research plan:

Ailanthus altissima biocontrol garden

2. Aster laevis 1. Asclepias tuberosa4. Erigeron speciosus 3. Aster novae-angliae6. Eupatorium perfoliatum 5. Eupatorium maculatum8. Monarda fistulosa 7. Heliopsis helianthoides10. Rudbeckia laciniata 9. Rudbeckia hirta12. Solidago canadensis 11. Rudbeckia triloba14. Solidago rigida 13. Solidago nemoralis16. Verbesina alternifolia 15. Solidago speciosa18. sunflowers 17. Asclepias syriaca19. Coreopsis 20. Shasta daisy21. sweet peppers 22. sweet peppers23. sweet peppers 24. Eu. mac./Cor. trip./Ech.

pur.

25. Collected plants

pasture uphill driveway

Non-native biocontrol has high rates of failure and low rates of

success, an average of 2.44 introduced organisms for every

species on which control is being attempted.

Using natives to control non-natives is a much lower risk and therefore safer than using non-

natives to try to control non-natives.

Non-natives, regardless of how much they are studied have a high risk associated with them

as is seen by the introduction of non-natives in the first place.

Collateral environmental effects are unknown with non-native biocontrols such as:

• breeding site competition with natives, • acting as food supplements for native predators which shifts population balance, • susceptibility to native diseases or magnifying them in the local ecosystems as a disease sink,• disease vectoring and … .

Whereas with native biocontrols, the collateral

environmental effects are known or predictable.

1.) is safe2.) is ethical3.) is necessary4.) that they understand the problems they are trying to solve5.) that they understand the total consequences of

their apparent solutions.6.) that they have spent time in the field to prove

that there are no possible alternatives already present.

I challenge the developers of non-native biocontrols to prove that what they are doing:

If bad theory and bad practice caused a problem, then bad

theory and bad practice are not going to solve it.

One small mistake with a non-native is the bioecosystem equivalent of a Chernobyl,

even though more subtle.

Are we willing to risk that when there are already good theory and good examples in place to

guide us?

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