On the Road to Extinction, Invasive Plants Do Have Significant Impacts

Lantana camarata

No studies have documented extinction of a native plant species caused by invasive ones. This has led to questions about whether invasive plants have truly significant impacts. (Of course, species extinction is not the only important impact).

These questions have been answered in a recent article by Paul Downey (of the Institute for Applied Ecology, University of Canberra) and David Richardson (of the Centre for Invasion Biology at Stellenbosch University, South Africa). A link to the article is provided at the end of this blog.

Downey and Richardson argue that studies have documented instances of invasive plant species putting native plants on the path – or trajectory – to extinction. Furthermore, plants go extinct more slowly than animals, often over centuries. As result, current approaches to analyzing impacts of invasive plants underestimate the damage that non-native species cause because they assume extinction will not result.

The authors name six “thresholds” along the trajectory to plant extinction. Each is affected by invasive plants:

  1. Plants die more quickly than they can be replaced by their offspring in some locations.
  2. Plants disappear from some locations entirely, but seeds or spores remain that could regenerate a new cohort of individuals.
  3. Some locations lose both individual plants and their propagules. This is a local extinction.
  4. The last locations hosting a species lose their individual plants, but in some places seeds or spores remain in the soil.
  5. The species is entirely lost in the wild with no individuals or propagules. The only survivors are held in botanic collections.
  6. Extinction. The remaining plants are lost, and the remaining seeds or spores are no longer capable of becoming new plants.

By focusing purely on full extinction — step six — plant conservationists lose sight of the threats to species as they occur and accumulate at each stage of the process. Without such attention we fail to act on opportunities to protect the species and counter the wider impacts of its disappearance.

Downey and Richardson note that plant invasions affect each component of a plant species’ population dynamics:  fecundity (seed production); death; immigration; and emigration (dispersal). Yet they could find no studies that have explored the effects of alien plants for all four components collectively.

A second explanation for scientists’ not documenting any extinctions caused by invasive plants is that it is extremely difficult to prove that every last individual or propagle of a plant species is dead . Many plant species have long-lived seed banks in the soil, or can regenerate from underground structures – so it is hard to know when that species is truly gone. This is especially true since seed banks are rarely monitored.

Furthermore, many of the conditions needed to demonstrate that alien plants have caused the extinction of native plant species have either not been measured, or have been examined for too short a time. The IUCN definition of extinction requires that data be collected over “a period that is appropriate for the life cycle of the species” (IUCN. 2014. Guidelines for using the IUCN Red List categories and criteria. Version 11. Prepared by the Standards and Petitions Subcommittee. Switzerland). Given the long persistence of plant species, the “appropriate period” exceeds the timeline almost all of even the few long-term studies in invasion ecology.


Downey and Richardson say that relying on changes in species richness to assess the impacts of alien plants will not adequately predict or describe the effects of invasion. Such analysis especially will not provide evidence for a species crossing from Threshold 1 to 2 or 3 . Indeed, they assert, collective species richness measures could mask losses of some species in instances where additional species are also recorded (i.e. the losses are off-set by additions).


The authors have found abundant evidence of invasive plants driving native plants along this extinction trajectory. They cite several examples of an invasive plant causing a “threshold effect” – that is, increases in alien plant cover or density result in decreased native plant species diversity or richness. They define this as the native species crossing from Threshold 1 to 2. Among the examples provided are several species in Australia and New Zealand and Lonicera maackii in the United States.


The authors also provide examples of species causing “extinction debts” – that is, a significant time lag between the introduction of an alien species initiating a native species’ movement along the trajectory and its actual extinction. One mechanism is by reducing native plants’ seed production. Again, Lonicera maackii is cited.

Downey and Richardson also note the potential downsides of invasive plant control measures.

In the end, the authors urge that scientists “… shift attention away from the end point of the extinction trajectory … to give due consideration of the full series of processes that drive declines of populations of native species.”

As Richardson has said in an interview with Oxford University Press, “… There is absolutely no doubt that alien plant invasions are eating away at native plant biodiversity. Many native plant species — probably HUNDREDS of species — are precariously close to being functionally extinct and survive as the ‘living dead’.’”


Source: Downey, P.O., D.M. Richardson. 2016. Alien plant invasions and native plant extinctions: a six-threshold framework. AoB Plants, 2016; 8: plw047 DOI: 10.1093/aobpla/plw047 ; open access, available at http://aobpla.oxfordjournals.org/


Posted by Faith Campbell

Campbell Wins Award from State Foresters



We are delighted to note that CISP Vice President Dr. Faith Campbell recently received the John Shannon Current Achievement Award for Partnerships from the National Association of State Foresters (NASF).

She was among nine individuals honored on September 21, 2016, at the group’s annual meeting in Savannah, Georgia. All recipients “have made outstanding contributions in wildland fire protection, urban and community forestry, forest management and overall leadership” according to NASF. Each was nominated by the organization’s members and partners for accomplishments in promoting, supporting and strengthening the forestry community nationwide. “Every year we are inspired by the achievements of so many leaders and partners in the forestry community, who are working to ensure the future sustainability of our nation’s trees and forests,” said Wisconsin State Forester Paul DeLong and NASA President.*

The Association noted that Faith has spent more than twenty years working on invasive species issues for several environmental or conservation organizations, including The Nature Conservancy, American Lands, and the Natural Resources Defense Council.

We at CISP couldn’t agree more that Faith is an inspiring and long-standing leader. She has extraordinary expertise regarding the non-native forest pests that threaten our Nation’s forests. Her voice is forthright and insistent — urging us ever onward to strengthen national and international policy to limit these burgeoning threats.


Please join us in congratulating her on this much-deserved honor.

Peter Jenkins

Phyllis Windle



* NASF press release at: http://www.stateforesters.org/2016-state-forestry-awards-recognize-excellence-forestry



Invaders Put Another Bird at Risk


i`iwi; photo by James Petruzzi; courtesy of American Bird Conservancy

As noted in an earlier blog (“When Will Invasive Species Get the Respect They Deserve?” May 2016),  invasive species can cause extinctions – especially on islands.  I have posted other blogs about the invasional meltdown in Hawai`i (“Hawaii’s unique forests now threatened by insects and pathogens” October 2015).

A further demonstration of the meltdown is the decision by the US Fish and Wildlife Service (USFWS) to propose listing  another Hawaiian honeycreeper (bird) – the i`iwi (Drepanis (Vestiaria) coccinea) as a threatened species.  Already, some 20 Hawaiian forest birds are protected under the Endangered Species Act.  Many, although not all, are threatened by the same factors as the i`iwi.

The proposal, which summarizes an extensive supporting report, is available here.  USFWS is accepting comments on the proposal that are submitted to the USFWS’  website before November 21.

The proposal documents the tragedy of Hawai`i. The i`iwi was once almost ubiquitous on the islands, from sea level to the tree line. Today the bird is missing from Lanai; and reduced to a few individuals on Oahu, Molokai, and west Maui. Remaining populations of i`iwi are largely restricted to forests above ~ 3,937 ft (1,200 m) on Hawaii Island (Big Island), east Maui, and Kauai.

In the past, hunting for the bird’s striking red feathers and agricultural conversion doubtless affected the i`iwi’s populations. Since the early 20th Century, though, the threats have all been invasive species.

The USFWS has concluded that the principal threat is disease: introduced avian malaria  — caused by the protozoan Plasmodium relictum and vectored by introduced mosquitoes (Culex quinquefasciatus). A second disease, Avian pox (Avipoxvirus sp.), is also present but scientists have not been able to separate its effects from those of malaria. Both vectored by the southern house mosquito.

I`iwi are very susceptible to avian malaria; in lab tests, 95% of birds died.


I’iwi on `ohi`a blossom at Hakalau NWR; photo by Daniel J. Lebbin; courtesy of American Bird Conservancy

I`iwi alive now have survived because they live in forests at sufficiently high elevations; there, cooler temperatures reduce the numbers of mosquitoes, and thus transmission of the disease.  However, the birds must fly to lower elevations in certain seasons to find flowering plants (the i`iwi feeds on nectar) – and then becomes exposed to mosquitoes.

Worse, climate change has already caused warming at higher elevations, and is projected to have a greater impact in the future.  The rising temperatures predicted to occur – even if countries meet their commitments from the December 2015 meeting of the UN Framework Convention on Climate Change – will result in upslope movement of mosquitoes. As a result, according to three studies reviewed by the USFWS, the i`iwi will lose 60 – 90% of its current (already limited) disease-free range by the end of this century, with significant effects occurring by 2050.

I`iwi occur primarily in closed canopy, montane wet or montane mesic forests composed of tall-stature `ohi`a (Metrosideros polymorpha) trees or in mixed forests of `ohi`a and koa (Acacia koa) trees. The i`iwi’s diet consists primarily of nectar from the flowers of `ohi`a  and several other plants, with occasional insects and spiders.



Hakalau National Wildlife Refuge; USFWS photo

The i`iwi’s dependence on `ohi`a creates another peril, because `ohi`a trees are vulnerable to alien diseases – both ohia rust and, especially, rapid ohia death or Ceratocystis ohia wilt. (Read descriptions of both diseases here.  As of September 2016, rapid ohia death has been found only on Hawai`i – the “Big Island”. However, 90% of all i`iwi currently reside on the Big Island! Worse, in future the relatively large area of high-elevation `ohi`a dominated forest on the Big Island was expected to be the principal refuge of the i`iwi from the anticipated climate-driven up-slope movement of malaria. However, as just noted, the Big Island’s trees are now being killed by disease. If rapid ohia death continues to spread across the native `ohi`a forests – on Hawai`i and potentially on the other islands – it  will directly threaten i`iwi by eliminating the limited, malaria-free native forest areas that remain for the species.

Rapid `ohi`a death (ROD) is caused by two distinct strains of the widely introduced pathogen Ceratocystis fimbriata.  It was first detected in the Puna District of Hawai`i in 2012. The disease has since been detected across a widening area of the Big Island, including on the dry side of island in Kona District (See map here.  The total area infested has increased rapidly, from ~6,000 acres in 2012 to 38,000 acres in June 2016.  Since symptoms do not emerge for more than a year after infection, the infested area is probably larger.  ROD kills `ohi`a in all size and age classes. There is no apparent limit based on soil types, climate, or elevation. O`hi`a growing throughout the islands appears to be vulnerable, from cracks in new volcanic areas to weathered soils; in dry as well as mesic and wet climates. The pathogen is probably spread by spores sticking to wood-boring insects and – over short distances – wind transport of insect frass.

Federal and state agencies are spending $850,000 on research on the disease, possible vectors, and potential containment measures.  Additional funds would be needed to implement any strategies, and to expand outreach  to try to limit human movement of infected plants or soil.

The Hawaii Department of Agriculture adopted an interim rule in August, 2015  which restricts the movement of `ohi`a plants, plant parts, wood, and frass and sawdust from Hawai`i Island to neighboring islands. Soil was included in the interim rule with an effective date of January 1, 2016. In March 2016, HDOA approved permit conditions for movement of soil to other islands. The interim rule is expected to be made permanent at a meeting of the Board of Agriculture on 18 October.

Other invasive species threatening the i`iwi are feral ungulates, including pigs (Sus scrofa), goats (Capra hircus), and axis deer (Axis axis).  All degrade `ohi`a forest habitat by spreading nonnative plant seeds and grazing on and trampling native vegetation. Their impact is exacerbated by the large number of invasive nonnative plants, which prevent or retard regeneration of `ohi`a forest. Drought combined with invasion by nonnative grasses have promoted increased fire frequency and the conversion of mesic `ohi`a woodland to exotic grassland in many areas of Hawaii.

The feral pigs pose a particular threat because by wallowing and overturning tree ferns (Cibotium spp.)  they create pools of standing water in which the mosquitoes breed.  The US FWS has concluded that management of feral pigs – across large landscapes – might be a strategic component of programs aimed at managing avian malaria and pox.

One possible source of hope: research into genetic manipulation of the mosquito disease vector by using tools from synthetic biology and genomics (see draft species status report . Considerable research is probably necessary before such a tool might be implemented.

Threat of Plant Pest Threat to Endangered Animals is Not Limited to Hawai`i

The USFWS is struggling to deal with the threat posed by plant pests to listed species. In San Diego, California, FWS personnel are trying to decide how to address the threat posed by the Kuroshio shot hole borer (read description here  to willows which constitute essential riparian habitat for the least Bell’s vireo.

Numerous cactus species that have been listed as endangered or threatened might be attacked by two insects from Argentina, the cactus moth and Harissia cactus mealybug (see my blog from October 2015; or read descriptions here .


Endangered Species Agencies Need to Coordinate with Phytosanitary Agencies

A growing number of species listed under the Endangered Species Act are being threatened by damage to plants from non-native plant insects and pathogens. This growing damage affects not just listed plants – such as the cacti mentioned in this and the October blogs; but also plants that are vitally important habitat components on which listed animals depend. The USFWS needs to engage with other federal and state agencies and academic institutions which are working to prevent introduction of additional plant pests, slow the spread of those already in the United States, and develop and implement strategies intended to restore plant species that have been seriously depleted by such pests. The USFWS should, therefore, work more closely with USDA Animal and Plant Health Inspection Service and Forest Service. USFWS must, of course, continue to work with experts in wildlife and wildlife disease.

Similarly, state wildlife agencies also need to coordinate their efforts with their counterparts in state departments of Agriculture and divisions of Forestry.

Many agencies in Hawai`i play crucial roles in protecting the Islands’ unique plant and animal communities:

  • U.S. Department of the Interior: Fish and Wildlife Service, National Park Service, United States Geological Service Biological Resources Division
  • US. Department of Agriculture: APHIS, Forest Service, Agriculture Research Service, National Institute of Food and Agriculture
  • US. Department of Homeland Security Bureau of Customs and Border Protection.
  • Hawai`i State Department of Agriculture and Department of Land and Natural Resources

Hawaiians of all types – federal and state employees and agencies, academics, and conservationists – deserve our thanks for promptly taking action of rapid ohia death.  All parties should make every effort to obtain the remainder of the funds needed to carry forward crucial research on ROD and avian malaria.  Those of us from the mainland need to support and help their efforts.


Posted by Faith Campbell

CISP files multi-species listing petition with US Fish & Wildlife Service – per Lacey Act




Alburnus alburnus photo by David Perez


Last Friday morning, I delivered a Petition to the Secretary of the Interior’s office the roots of which go back 15 years to 2001. The title: Petition: To Amend 50 CFR §16.13 to List 43 High Risk Fish, Crayfish, and Mollusk Species as Injurious Species under the Lacey Act. (For a copy of the petition, use the “contact us” button on the CISP webpage.) I was really excited to file this on CISP’s behalf because it is the logical expansion of a more proactive approach to preventing introductions of invasive, disease-carrying, or otherwise “injurious” non-native animals that we don’t want running around in the United States. We already have scores of invaders (starlings, red lionfish, Burmese pythons, feral hogs, Asian carps, zebra and quagga mussels, tegus and on and on). We need to start doing multi-species listing proposals in order to change what has been an extremely slow process into one that works at a pace that can actually protect our nation’s resources – and people – from the risks of this age of vast globalized trade in live fish and wildlife.


Back in 2001, the National Invasive Species Council adopted its first Management Plan. One element in it was to adopt a science-based screening method aimed at identifying the highest risk non-native animals that we should keep out of the country.  This was to have been completed by about 2006.  I was appointed long ago (so far back I can’t remember the year) to the committee tasked with this responsibility.  The Committee went through fits and starts and sometime in the mid-2000s just crashed into nothingness and stopped meeting.  But, a dedicated U.S. Fish and Wildlife Service (FWS) biologist in the Midwest Region — Mike Hoff — kept at it for years on a shoestring budget and around 2011 he got some real funding and was able to get his animal screening project staffed. Lo and behold, they started developing lists of high-risk species based on robust scientific predictions. I won’t go into the models he used and the peer-review he had to go through. Suffice it to say that process took about 3 more years before Mike Hoff and his colleagues could convince the FWS to actually start publicly posting the results of their screening work. But, starting in 2014 they posted several and in late 2015 they posted them in earnest. Now there are 150 Ecological Risk Screening Summaries (ERSSs) on the bureau’s website.


Out of the 150 species, 63 pose a “high” overall risk of invasiveness/injuriousness.  For funding and historical reasons most are aquatic species that could invade in the Great Lakes region, but even so it is a great beginning. The 63 species include 46 fishes, 8 crustaceans, and 9 mollusks. One fish on the website (mrigal, Cirrhinus cirrhosus) appears to be labeled “high risk” in error and one of the mollusks (zebra mussels, genus Dreissena) is already listed under the Lacey Act. Also, Interior already has formally proposed that 11 of the 63 species on the website should be listed as “injurious”. That is, almost exactly one year ago the agency proposed to add 10 of the non-native fish and one crustacean. Thus, those 11 are not included in this new Petition. The FWS needs to take action on them soon.


UPDATE: On Sept. 29th the FWS finalized its rule listing all 11 of those species. The regulation and the detailed FWS explanation for it published in the Federal Register set a strong precedent and a useful template for listing the 43 species in the Petition as well.


Now this Petition, which I co-wrote with my CISP colleague Phyllis Windle, PhD., should be the USFWS’ next multi-species listing. The 43 “high risk” species proposed in it are listed at the end of this blog. The Petition excludes 7 species with posted ERSSs that were “high: overall,” but were below a high rating for either their history of invasiveness or climate match. As a result, the 43 below represent the highest range of the FWS’s identified high risks. Species like the Devil firefish, virile crayfish and the bleak – just their names makes me not want them here – pose unacceptable risks.


While the voluntary program promoted by the FWS on its webpages along with the ERSSs is a commendable hope, a “please do not import” approach cannot be relied upon. Administrations and websites change and some industry outliers won’t follow voluntary measures anyway – some even see them as creating a business opportunity. As I have watched (and supported), Mike Hoff and the FWS invested a significant amount of funds and staff time over the last 10 years to develop this screening process and research and write the scores of posted ERSSs. Other experts were involved in designing the process and providing peer reviews at different stages. It would be a significant waste of taxpayer resources were the FWS not to follow through and take regulatory action for species posing a clearly high risk. None offers an essential benefit that outweighs its harm to the United States. Minimal to zero stakeholder opposition is expected to prohibiting them. So what are we waiting for? The listing Petition needs to get posted in the Federal Register for public comment and action started as soon as possible. This one is virtually a “no brainer”.


The proposed list additions are below. For a copy of the full Petition, use the “contact us” button the the CISP webpage.



(A) Bithynia tentaculata (faucet snail).

(B) Corbicula fluminea (Asian clam).

(C) Dreissena rostriformis bugensis (Quagga mussel).

(D) Limnoperna fortune (golden mussel).

(E) Potamopyrgus antipodarum (New Zealand mudsnail).

(F) Sinanodonta woodiana (Chinese pond mussel).



(A) Acanthogobius flavimanus (yellowfin goby).

(B) Alburnus alburnus (bleak).

(C) Alosa pseudoharengus (alewife).

(D) Cichlasoma bimaculatum (black acara).

(E) Coregonus lavaretus (powan).

(F) Ctenopharyngodon idella (grass carp).

(G) Cyprinella lutrensis (red shiner).

(H) Cyprinus carpio (common carp).

(I)  Gymnocephalus cernua (ruffe).

(J)  Hypomesus nipponensis (wakasagi).

(K) Ictalurus furcatus (blue catfish).

(L)  Misgurnus anguillicaudatus (Oriental weatherfish).

(M) Morone americana (white perch).

(N) Neogobius melanostomus (round goby).

(O) Odontesthes bonariensis (Argentinian silverside).

(P) Oreochromis aureus (blue tilapia).

(Q) Oreochromis mossambicus (Mozambique tilapia).

(R) Oreochromis niloticus (Nile tilapia).

(S) Parachromis managuensis (Jaguar guapote).

(T) Poecilia reticulate (guppy).

(U) Pterois miles (Devil firefish).

(V) Pterois volitans (red lionfish).

(W) Pterygoplichthys pardalis (Amazon sailfin catfish).

(X) Pterygoplichthys multiradiatus (Orinoco sailfin catfish).

(Y) Pterygoplichthys disjunctivus (vermiculated sailfin catfish).

(Z) Pylodictis olivaris (flathead catfish).

(AA) Rhodeus ocellatus (rose bitterling).

(BB) Sarotherodon melanotheron (blackchin tilapia).

(CC) Scardinius erythrophthalmus (rudd).

(DD) Tilapia mariae (spotted tilapia).

(EE) Tilapia zillii (redbelly tilapia).



(A) Oronectes limosus (spiny-cheek crayfish).

(B) Oronectes propinquus (northern clearwater crayfish).

(C) Oronectes rusticus (rusty crayfish).

(D) Oronectes virilis (virile crayfish).

(E) Pacifastacus leniusculus (signal crayfish).

(F) Procambarus clarkia (red swamp crayfish).


Posted by Peter Jenkins

Invasive Earthworms Need Action!

 worm_medAmynthes agrestis; National Park Service photo


Earthworms have been largely ignored as a class of invaders. But evidence is accumulating that their numbers and impacts are too significant to ignore.


Non-indigenous earthworms began arriving in the Americas with the first European colonists and they are now widespread. One study (see summary of Reynolds and Wetzel 2008 here) found 67 introduced species among the 253 earthworm species in North America (including Mexico, Puerto Rico, Hawaii, and Bermuda).  In Illinois, 20 of the 38 species are introduced. Nuzzo et al. 2009 recorded a total of 11 earthworm species – all nonnative – at 15 forest sites in central New York and northeastern Pennsylvania.


Earthworms are good invaders – they reproduce quickly and are easily transported to new places – both carelessly and deliberately for bait, composting, or other uses.


As ecosystem engineers, invasive earthworms cause significant impacts to the soil and leaf litter, as well as to plants and animals dependent on those strata.  However, they are little studied and few efforts been made to address their threat.  Wisconsin is the pioneer (see below).


Ecosystem Engineers: Impacts on Soil, Plants, and Animals


Invasive alien earthworms cause enormous damage in forest environments. (I have seen no information about the damage they might cause in other natural systems.)  Earthworms can change soil chemistry, soil structure, and the quantity and quality of the litter layer on the soil surface. Changes include rapid incorporation of leaf litter into the soil, alteration of soil chemistry, changes in soil pH, mixing among soil layers, and increased soil disturbance. Such changes have been shown to harm native plant species – both herbaceous ones on the forest floor as well as the regeneration of woody vegetation, including trees.  See the review just published by Craven et al. 2016 and Hale and Nuzzo references below).


Craven et al. (2016) conducted a meta-analysis of 645 observations in earlier publications. They sought to measure the effects of introduced earthworms on plant diversity, cover of plant functional groups, and cover of native and non-native plants. Sites with a higher the diversity of invading earthworms – with associated variety in behaviors (see below) – had greater declines in plant diversity.  Higher earthworm biomass or density did not reduce plant diversity but did change plant community composition:  cover of sedges and grasses and non-native plant species significantly increased, and cover of native plant species (of all functional groups) tended to decrease. The increase in non-native plant cover in areas with higher earthworm biomass is thus an example of ‘invasional meltdown’ as propounded by Simberloff and Von Holle in 1999.


Craven et al. 2016 propose several direct and indirect mechanisms by which introduced worms might affect plant species. These include ingestion of seeds or seedlings, burying seeds, and alteration of water or nutrient availability, mycorrhizal associations, and soil structure. European and Asian plant species that co-evolved in the presence of earthworms could better tolerate earthworms’ presence.


Important Questions


Craven et al. 2016 note that the interaction of the invader-related factors with other site-related conditions such as deer browsing, fire history, forest management, and land-use history require further study to disentangle. Many other questions need to be answered, too.

Although Craven et al. (2016) do not specify the geographic range of the studies analyzed, I believe most were conducted in the northern and northeastern regions of the United States and some parts of Canada. It would be interesting to see if these studies’ findings differed from those carried out in Great Smoky Mountains National Park on the Tennessee-North Carolina border. The latter is an area where – unlike the northern states – earthworms were not wiped out by the most recent glaciation.  (See references by Bruce Snyder and Jeremy Craft, below.)


The finding that worm species diversity is associated with decreased plant species diversity seems to indicate that worms’ impacts might vary depending on the behavior of the worm in question – especially whether the worms remain on or near the soil surface and — if not — how deeply they burrow.  Are studies under way to clarify these differences?


Furthermore, do the impacts of European worms – the subjects of most of the studies carried out in Minnesota, New York, and Pennsylvania – differ substantially from the impacts of Asian earthworms? Or are any differences explained better by the species’ activity in the soil (e.g., depth of burrows) than their origins?


Impacts of earthworms on wildlife are less studied and perhaps less clear.  Several studies have focused on salamanders because of their known dependence on leaf litter. In a study of 10 sites in central New York and northeastern Pennsylvania, Maertz et al. 2009 found that salamander abundance declined exponentially with decreasing volume of leaf litter. They suggested that the salamander declines were a response to declines in the abundance of small arthropods, a stable resource.

A study by Ziemba et al. (2016) in Ohio involved Asian worms (genera Amynthas and Metaphire) rather than the European worms most often included in studies carried out in Minnesota, New York, and Pennsylvania.  These authors found a complex picture: earthworm abundance was negatively associated with juvenile and male salamander abundance, but had no relationship with female abundance.

Craft (2009) found that reduced leaf litter mass in invaded areas of Great Smoky Mountains National Park diminished habitat for both salamanders and salamander prey.

Others have studied millipedes – a largely unappreciated example of biological diversity in the Southern Appalachian Mountains – in Great Smoky Mountains National Park. Snyder and colleagues (2013) found that earthworms in the genus Amynthas altered soils by decreasing the depth of partially decomposed organic horizons and increasing soil aggregation. The result was a significant decrease in millipede abundance and species richness – probably as a result of competition for food.

Results from a study of earthworms’ effects on the Park’s food web by Anita Juen and Daniela Straube, begun in 2010, have not yet been published (pers. comm. from GRSM staff).

Even birds might be affected by worm invasions. One study in Wisconsin found that hermit thrush and ovenbird populations are lower in areas infested by worms. Possible reasons for the decline are that nests (on the ground) are more vulnerable to predation when located in the grasses promoted by worms, and a reduction in invertebrates fed to nestlings.


Expanding Risks

Several non-native earthworm species have been collected (so far) only from greenhouses or other places of indoor cultivation.  But can we be sure that they are not being spread to yards, parks, and other places halfway to natural systems through movement of plants and mulch?


Earthworms are extremely difficult to manage once established.

Are these challenges the reasons why few official efforts to control earthworm spread have been adopted? Or is it the animals’ public image – they are widely regarded as “good” critters that enrich the soil and facilitate composting. Or is it that trying to control worms will require enhanced regulation of the nursery and green waste industries?

worms1Amynthes photo; from Wisconsin DNR website

Wisconsin Is the Policy Pioneer

Wisconsin stands out for trying to address the issue! The state’s conservation and phytosanitary officials became alarmed when they detected Amynthas species in the University of Wisconsin Arboretum in 2013.  This is the site of regular plant sales,a likely pathway for spread.  Wisconsin now knows this genus of worms to be present in 21 counties, mainly along urban corridors.  They have not yet been found in the state’s forests.

Wisconsin is acting to protect its forests despite Amynthas worms having been present in the United States for over a century: Snyder, Callaham and Hendrix 2010 say several species of Amynthas were documented in Illinois and Mississippi by the 1890’s.  Some 15 species are recorded as established and widespread across the eastern United States (Reynolds and Wetzel 2004).


Wisconsin has classified the Amynthas genus as “restricted” – so their movement is now regulated. The risk of spread appears to be greatest through mulch produced from leaves collected in residential communities. The state held a workshop during which the regulated industry developed best management practices to address that risk. The Wisconsin Department of Natural Resources has posted a web page with information about identifying the worms and the BMPs. (Wisconsin DNR has also been a leader in tackling the firewood pathway.) The Wisconsin Department of Agriculture put the worm issue on the agenda of the National Plant Board in August 2016 and urged other states to take action.

The Wisconsin DNR webpage has

  • ID cards and other information to aid identification, g., photos of worms and the “coffee ground” soil they create;
  • a brochure with the state’s new “best management practices”
  • educate yourself and others to recognize jumping worms;
  • watch for jumping worms and signs of their presence;
  • ARRIVE CLEAN, LEAVE CLEAN – Clean soil and debris from vehicles, equipment and personal gear before moving to and from a work or recreational area;
  • only use, sell, plant, purchase or trade landscape and gardening materials and plants that appear to be free of jumping worms; and
  • only sell, purchase or trade compost that was heated to appropriate temperatures and duration following protocols that reduce pathogens.

What’s Up Where You Are?

What is your state doing to slow the spread of invasive earthworms?

  • Do nursery inspectors look for earthworms when approving plant shipments? Craven et al. 2016 findings re: higher impacts on plants as number of worm species rises demonstrate the importance of slowing spread of new species even into areas that already have some non-native earthworms.
  • Are professional associations of nurserymen and green waste recyclers educating their members about the damage caused by invasive earthworms and steps they can take to minimize worms’ spread to new areas?
  • Are organizations of anglers and gardeners in your state educating their members about the damage caused by invasive earthworms and steps they can take to minimize worms’ spread to new areas?
  • Are ecologists studying earthworm invasion impacts in other parts of the country? In non-forested ecosystems?
  • Are conservation organizations initiating or joining outreach efforts?
  • Can worm-education efforts be joined with h more robust public and private outreach focused on aquatic invaders, invasive plants, or firewood?



Bohlen, P.J., S. Scheu, C.M. Hale, M.A. McLean, S. Migge, P.M. Groffman, and D. Parkinson. 2004.  Non-native invasive earthworms as agents of change in northern temperate forests. Front Ecol Environ 2004; 2(8): 427–435

Craft, J.J. 2009. Effects of an invasive earthworm on plethodontid salamanders in Great Smoky Mountans National Park. Thesis prepared at Western Carolina University.

Craven, D., M.P. Thakur, E.K. Cameron, L.E. Frelich, R.B. Ejour, R.B. Blair, B. Blossey, J. Burtis, A. Choi, A. Davalos, T.J. Fahey, N.A. Fisichelli, K. Gibson, I.T. Handa, K. Hopfensperger, S.R. Loss, V. Nuzzo, J.C. Maerz, T. Sackett, B.C. Scharenbroch, S.M. Smith, M. Vellend, L.G. Umek, and N. Eisenhauer. 2016.The unseen invaders: intro earthworms as drivers of change in plant communities in No Am forests (a meta-analysis). Global Change Biology (2016), doi: 10.1111/gcb.13446 available here.

Hendrix, P.F. 2010. Spatial variability of an invasive earthworm (Amynthas agrestis) population and potential impacts on soil characteristics and millipedes in the Great Smoky Mountains National Park, USA. Biological Invasions DOI 10.1007/s10530-010-9826-4

Maertz, J.C., V. Nuzzo, B. Blossey.  2009. Declines in Woodland Salamander Abundance Associated with Non-Native Earthworm and Plant Invasions. Conservation Biology Volume 23, Issue 4 August 2009  Pages 975–981

Nuzzo, V.A., J.C. Maerz, B. Blossey. 2009. Earthworm Invasion as the Driving Force Behind Plant Invasion and Community Change in Northeastern North American Forests. Conservation Biology Volume 23, Number 4, 966-974.

Simberloff, D.  and Von Holle, B. 1999. Positive interactions of nonindigenous species: invasional meltdown? Biological invasions 1, 21-32

Snyder, B.A., M.A. Callaham, C.N. Lowe, P.F. Hendrix. 2013. Earthworm invasion in North America: food resource competition affects native millipede survival and invasive earthworm reproduction. Soil Biology and Biochemistry 57, 212-216

Ziemba JL, Hickerson C-AM, Anthony CD. 2016. Invasive Asian Earthworms Negatively Impact Keystone Terrestrial Salamanders. PLoS ONE 11(5): e0151591. doi:10.1371/journal.pone.0151591


See also:

Global picture: https://www.newscientist.com/article/mg19325931-600-war-of-the-worms/

Great Lakes Wormwatch website: http://www.nrri.umn.edu/worms/research/publications.html  

Illinois Natural History Survey webpage: http://wwn.inhs.illinois.edu/~mjwetzel/IllinoisEarthworms.html

Wisconsin  DNR http://dnr.wi.gov/topic/invasives/fact/jumpingWorm/index.html

Information on western Canada:



Native Earthworms of British Columbia Forests: http://www.cfs.nrcan.gc.ca/pubwarehouse/pdfs/5102.pdf


Posted by Faith Campbell

Dr. Sarah Reichard 1957-2016

We  mourn the sudden and unexpected death of Sarah Reichard, Professor in the School of Forest Resources at the University of Washington and Director of the UW Botanical Garden. For more than 25 years, Sarah was a leading researcher on invasive plants. She studied their traits; sought to predict  their invasive ability; searched for ways to detect new invaders early; and examined the effects of plant invaders on native ecosystems. She also engaged the nursery industry, botanical gardens, and other horticultural groups in addressing invasive plant threats. She brought an open style, compassion, deep thoughtfulness — and yet a burning desire for righteous change — to all this work.

Sarah established her expertise early and was long a recognized expert.She published widely — in academic journals, gardening magazines, and policy papers.  Most recently, she authored the well-received book, The Conscientious Gardener: Cultivating a Garden Ethic. Also, Sarah was a key organizer and participant in meetings — both international and national — that addressed invasive species. Many of us in the conservation community relied upon her work and advice to guide invasive plant policy.

We join her husband, her colleagues at the University of Washington, and invasive plant experts around the world in mourning Sarah’s untimely death. Our world is a poorer place without her bright and generous spirit.


Faith Campbell

Phyllis Windle

Peter Jenkins



Let’s Work Together to Curtail Threat to Our Forests from Non-Native Pests

Dear Forest Pest Mavens,

I believe you agree with me that non-native insects, pathogens, earthworms … and other organisms! … pose significant threats to North America’s tree species and the complex ecosystems of which they are such important components.

I hope you also agree that our society’s efforts to counter this threat fall far short of what is needed.

  • Official phytosanitary policies are not as strong as needed to prevent introduction and spread of these tree-killing pests.
  • Worse, those policies are not always enforced assertively – as I documented in my blog about a shipment of auto parts posted on 9 August.
  • The Congress does not provide sufficient funds and other resources to support active detection and response programs – either early in an invasion or later.
  • Businesses that import or trade in goods or packaging that can transport pests are not held responsible for taking actions aimed at reducing the likelihood of such transport or supporting recovery efforts. Opposing free trade has become a hot button election issue but one of its worst impacts — wholesale movement of pests — is never mentioned.

As I noted in my earlier blog, a key reason we see these weaknesses is because those who want stronger programs have not had an effective voice in educating federal policy-makers – the USDA secretary, senators, and members of Congress – about the damage caused by introduced tree-killing pests and the governmental actions needed to counter those impacts.

The election provides both a deadline and an opportunity.

The deadline: we should try to finalize some APHIS-proposed actions before this Administration leaves office. Outgoing officials often feel freer to take bold actions at this time.

The opportunities:

  • New officials who take office in January might be open to addressing “new” issues. We must begin efforts now to get our “asks” on their agenda.  Specifically, we should approach the  senators who will question appointees to USDA Secretary and Under Secretary positions during their confirmation processes.  We should urge them to ask candidates  how they would address plant pests and to make firm, specific commitments to do so
  • Also, Congress is beginning to consider provisions to include in the next Farm Bill (due to be passed by 2019).

Several coalitions work to raise the political profile of non-native, tree-killing pests, i.e., the Coalition Against Forest Pests; Sustainable Urban Forestry Coalition; Reduce Risk from Invasive Species Coalition; Continental Dialogue on Non-Native Forest Insects and Diseases.   Many of the nation-wide forest-related organizations are members of one or more of these coalitions and I work hard for many of them. They are absolutely essential. . .

However, such “big tent” coalitions are unlikely to press for  truly bold solutions, especially if new policies  involve serious costs to economic interests or industries that are part of their membership. There is nothing nefarious in this; it is the way coalitions operate. In the case of forests pest issues, though, the absence of more forceful and nimble groups leaves a policy vacuum that no one currently  fills.

Furthermore, these coalitions don’t offer an opportunity to concerned individuals and smaller organizations to learn about phytosanitary threats or provide them with opportunities to influence policy.

In the past, I have tried to provide this information through my one-way emails and blog postings.  I would like now to upgrade these communications and to provide you with a way to interact with me and others, as well as to form joint positions.  The goal is to re-balance the politics of phytosanitary policy – so that our political leaders understand and support both adoption and enforcement of strong, effective phytosanitary measures.

I suggest that we form a new, loose “coalition of the willing” who are ready to speak up and seek ways to stay abreast of developments and opportunities and to coordinate their actions with those of like-minded people.  I suggest a loose structure –

  • I undertake to set up an email network that everyone could use. It would:
    • communicate information about pest threats and opportunities to engage;
    • communications could be initiated by anyone in the group (either through a “reply all” function or my promise to re-send any email sent to me — with the request that I do so);
    • encourage people to work together – with my assistance – to form joint positions;
    • provide lists of key contacts for specific issues — perhaps with specific talking points, letter templates, etc., to help in reaching out;
  • There would be no cost to participants;
  • Participants could take part anonymously if they wish – either generally or on specific issues;
  • If there is sufficient interest or need, we could form a steering committee to streamline and help guide the work;
  • Our goal would be communications that are straight-forward and clear — to each other and to policymakers — while avoiding gratuitous insults or insinuations.

Examples of issues on which I believe a new group could productively engage (and which the “big tent” coalitions likely will avoid) are:

  • Helping APHIS finalize its proposal to require that wood packaging coming from Canada conform to ISPM#15 standards (see blog posted on 9 August). We need to press the USDA leadership to approve the proposal; then press the Office of Management and Budget to approve it.
  • Press USDA to take two steps to improve enforcement of ISPM#15:
    • End the policy of not fining importers for non-compliant wood packaging until they have five (!) non-compliances within a single year.
    • Declare wood packaging to be a high-risk import and thus subject to mandatory inspection by Customs
  • Press Customs and Border Protection to include wood packaging compliance under its Customs-Trade Partnership Against Terrorism (C-TPAT) program.
  • Seek agreement on a strategy to encourage importers to shift to packaging made from materials other than solid wood boards. Proposals range from new regulatory requirements to C-TPAT to green certification-type voluntary programs.

I welcome suggestions for other topics we might explore!

Please let me know that you would like to join this coalition.  Please  feel free to forward this message and to invite others to join in.

[use the “contact” button on the www.cisp.us website]


A Red List for Trees!

16 dead sweet bay + grpF.T. Campbell  dead sweetbay, Florida Everglades

At the global level, the World Conservation Union (IUCN) is the recognized leader in conservation.  Information from the IUCN’s Red List has been widely used to inform conservation policies and legislation, as a tool for environmental monitoring and reporting, and to prioritize areas for conservation action.


The IUCN is holding its World Conservation Congress in Honolulu during the first half of September.  The several sessions focused on both invasive species and forests have been grouped into “Journeys”.  The invasive species Journey schedule is available here.  The schedule for the forest Journey is available here   I don’t think either puts much emphasis on the year-old Tree Specialist Group.


Over the decades, the Union has increasingly engaged on plant conservation issues. The plants under consideration now include trees! There are multiple ways that you can be part of this important effort. Details are below. One of the efforts’ leaders assures me that the IUCN process will address tree species not yet “endangered” but under severe pressure – currently or virtually certainly in the near future – from established non-native insects and pathogens.


The IUCN has noted that trees have high ecological, economic, and cultural value. Forests are being converted or degraded by many human-related activities, including overharvesting, fire and grazing – to say nothing of climate change and non-native pests. Yet – the impacts of forest conversion and degradation on tree species per se are largely unknown. How many tree species qualify for a “Red List” category: extinct, critically endangered, endangered, or vulnerable? (For a discussion of the criteria applied in assigning categories, go here.

(Of course, full-scale extinction or endangerment of a species is the extreme; ecological damage begins earlier and more locally, as the species declines as the result of a suite of pressures …)


The IUCN has formed a Global Tree Specialist Group to conduct a comprehensive conservation assessment of the world’s tree species, linked to IUCN’s Red List. The effort is being led by the Tree Specialist Group  and the Botanic Gardens Conservation International (BGCI). The group’s mission, underlying considerations and process are described in an article published in the Oryx article cited below.


IUCN has recently completed analyses of extinction risk in selected animal groups. They concluded that 14% of bird, 33% of amphibian, and 22% of mammal species are either threatened or extinct.


Preparing the same type of analysis for tree species will be more complicated. First there are many more plant species than ones in the selected groups of animals. Scientists don’t know the total number of extant tree species. One estimate is 60,000.  If that estimate is in the ballpark, the status of approximately 84% of tree species has not yet been assessed. Assessments of tree species begun in the 1990s have resulted in approximately 9,500 species being included in one of the Red List categories.  They represent slightly less than half of all plant species listed.


To achieve the goal of assessing the status of all tree species by 2020, organizers plan to adopt the approach used successfully in the recent assessments of vertebrate groups – mobilizing global data sets (which have become more numerous and easier to use) and hundreds of volunteer experts.


To start, the Group is focused on specific plant families with high numbers of trees, e.g., Aquifoliaceae, Fabaceae, Fagaceae, Lauraceae, Meliaceae and Myrtaceae. Combined, these families include more than 20,000 species. Assessments of Betulaceae and Ebenaceae have already started, led by BGCI and the Missouri Botanical Garden, respectively.


Project leaders hope to complete 5,000 more tree assessments – new or updates – during 2016.


What is Under Way


Other IUCN specialist groups are assisting in assessing the status of trees in various geographic regions or with particular human uses. The IUCN Plants for People initiative is already assessing timber, medicinal and crop wild relatives. The Crop Wild Relative Specialist Group has prepared draft assessments for over 90 woody species of Malus, Prunus, Pistacia and Mangifera. Specialist Groups and Red List authorities in South Africa, Brazil, and East Africa and several island groups are contributing.


A third focus will be tree species presumed to be most at risk from climate change, e.g., montane and island trees. IUCN Specialist Groups in Hawai`i, New Caledonia, Galapagos, Mascarene Islands, Fiji, and Madagascar are working.


The BGCI is making progress on assessing Europe’s non-coniferous trees. If you wish to help, contact Malin Rivers at malin.rivers@bgci.org.


In North America, the U.S. Forest Service hosted a meeting on “Gene Conservation of Tree Species” at the Morton Arboretum in Chicago in May 2016. Murphy Westwood facilitated a special session during which “listing” experts from IUCN, NatureServe, USFS CAPTURE Program, and the U.S. Fish and Wildlife Service compared their assessment processes and discussed how data might be shared more efficiently. A goal of completing the IUCN Red List of North American Trees was agreed on. The Morton Arboretum will help coordinate the effort. To contribute please contact Murphy Westwood at mwestwood@morton.org.  


One suggestion was to conduct an IUCN Red List assessment for the genus Fraxinus. Two ash species – one Asian, one Central American – are included in the IUCN Red List (although one needs to be updated). Jeanne Romero-Severson of Notre Dame University has offered to undertake assessments for green ash, Fraxinus pennsylvanica, and black ash, Fraxinus nigra. If you wish to help, contact Sara Oldfield at sara@saraoldfield.net.


(I think several other species also warrant IUCN assessment, including redbay Persea borbonia, tanoak Notholithocarpus densiflorus, and whitebark pine Pinus albicaulis)


This IUCN effort represents yet a fourth set of people examining tree-pest interactions – people integrated into traditional, internationally-focused conservation organizations. There are at least three other groups already involved: (1) forest pest experts in academia and government agencies, (2) people who focus on invasive species, and (3) phytosanitary officials. I think that these latter three groups already interact less smoothly than would be ideal. How can we all combine our efforts to enhance protection programs?


Might more of the scientists who work on insects and pathogens attacking tree species join the IUCN Tree Specialist group? Might organizers of meetings make a greater effort to engage people from all four silos in discussions of strategies? Might some virtual for a be established that could facilitate communication across the gaps – perhaps emphasizing the gap between invasive species experts and phytosanitary officials?


Finally, how can we use the new focus on tree species’ degree of endangerment to enhance efforts to prevent and respond to invasions by non-native insects and pathogens? How do we link these concerns to existing attention to the ecological and economic impacts – which begin to manifest long before a species qualifies as “endangered”.  How can the various approaches reinforce each other?





Newton, A., S. Oldfield, M. Rivers, J. Mark, G. Schatz, N. Tejedor Garavito, E. Cantarello, D. Golicher, L. Cayuela, and L. Miles. 2015. Towards a Global Tree Assessment. Oryx, Volume 49, Issue 3, July 2015, pp. 410-415.


Explanatory information available at




The GTSG Newsletter is apparently available only to those who are part of the IUCN network.


For more information, contact Sara Oldfield, Co-Chair GTSG, at sara@saraoldfield.net




Posted by Faith Campbell

Biocontrol As a Strategy to Control Damage by Invasive Plants – is the Logjam Broken?


garlic mustard; Chris Evans,River to River CWMA;  Bugwood

As we all know, the United States is overrun by non-native plants.  As I noted in blogs posted in January and March, Rod Randall’s database lists more than 9,700 non-native plant species as naturalized in the U.S.  Not all 9,700 cause environmental damage. But hundreds do – a fact attested to by the various regional Invasive Plant and Exotic Pest Plant councils:

  • The Southeast Exotic Pest Plant Council lists approximately 400 invasive species.
  • The Mid-Atlantic Invasive Plant Council lists 285 invasive plants.
  • The Midwest Invasive Plant Network says the state agencies or state-level invasive plant councils in its region list more than 270 plant species as invasive, noxious, or pest species in the Midwest.
  • The California Invasive Plant Council lists 208.
  • Texas Invasives reports that there are more than 800 non-indigenous plant species in the state, of which 20 are considered invasive.


The Pacific Northwest and Northern Rockies councils do not provide lists on their websites.


The analysis of forest inventory data by Christopher Oswalt and colleagues — discussed in my blog in March — found that almost 40% of forest plots in the United States are invaded by alien plant species. Other than in Hawai`i, the most invaded region is forests in the eastern United States – where 46% of forest plots in the East harbor one or more of the invasive plant species included in the inventory process.


The March and earlier blogs discuss reasons why the invasive plant situation is likely to worsen over time.


Given the geographic extent of plant invasions and the environmental complications, expense, and other difficulties associated with managing invasive plants using mechanical or chemical tools, many place their hope in biological control. Scientists in the U.S. Forest Service, Agriculture Research Service, U.S Geological Survey, academia, and other institutions have devoted years to identifying promising biocontrol agents targeting some of the most widespread and damaging invasive plants.


Possible biocontrol agents have been identified for numerous invasive plant species  …  but relatively few have been approved for release.


Part of the delay is attributable to the necessity for caution to ensure that biocontrol agents are effective and do not become damaging invasive themselves.  This concern underlies the legal requirement that non-native biocontrol agents must be approved by USDA APHIS. APHIS permits are required for

  • Importation of live biocontrol agents into the U.S. or its territories
  • Interstate movement of live biocontrol agents (USDA policy allows movement of certain commercial entomophagous biocontrol agents without a permit)
  • Retaining live biocontrol agents after expiration of a permit
  • Movement of any live biocontrol agent from confinements of containment facility or for release into the environment.

The approval process is lengthy and complex – and frustrating! Its many steps were outlined in a presentation by a staffer in APHIS’ permit branch, Robert Tichenor, available here


As noted in the presentation, the process can take a decade or more between scientists initiating the search for possible agents to final approval. The scientists hoping to find useful biocontrol agents face possibly years of work to identify and obtain organisms that seem promising as biocontrol agents. The petitioner must then screen the putative agent(s) for efficacy and then for host specificity. Once this work has been completed, the scientist prepares a petition to APHIS asking that it approve release of the biocontrol agent(s).

At this stage, government agencies take over. When it receives a petition for release of a biocontrol agent, APHIS sends the petition to the Technical Advisory Group (TAG).  (For details about the TAG, go here.

Under the TAG charter, APHIS invites the following agencies to provide a representative to serve on the TAG: Army Corps of Engineers, Environmental Protection Agency; Department of Agriculture: APHIS, Agricultural Research Service, Forest Service, National Institute of Food and Agriculture, Natural Resource Conservation Service; Department of the Interior: Bureau of Indian Affairs, Bureau of Land Management, Bureau of Reclamation, National Park Service, Fish and Wildlife Service, Geological Survey. APHIS may also invite participation by State or other Federal government employees (one each) to represent the National Plant Board, Weed Science Society of America, and other Federal Agencies expressing interest.  Canada and Mexico are also asked their views.


The TAG reviews both the proposed plant list for host specificity testing and the petition for first-time field release. The TAG may suggest inclusion of certain test plants, identify conflicts of interest, and assess potential risks associated with an environmental release. In making their evaluations, TAG members are expected to represent their agency’s or organization’s perspective. The chairman seeks to build consensus. Then s/he conveys the recommendations to APHIS.


APHIS decides whether to proceed with the review process and so informs the petitioner and APHIS’ Policy and Program Development (PPD) division.  Using information in the Petition, APHIS prepares a Biological Assessment analyzing whether releasing the biocontrol agent might affect a species listed as endangered or threatened under the Endangered Species Act. This Biological Assessment is sent to the US Fish and Wildlife Service (FWS)  to initiate an “informal” consultation per Section 7 of the Endangered Species Act (16 U.S.C. Section 1536). The FWS’ review can take more than a year and can involve requests for additional information. For the proposed biocontrol project to proceed, APHIS must receive a letter from US FWS stating that US FWS  “concurs” with APHIS’ determination that release of the biocontrol agent is “not likely to adversely affect” listed species or designated Critical Habitat.


Upon receipt of the FWS concurrence letter, APHIS begins preparing an environmental assessment (EA), and consults with any affected Native American tribes. The draft EA is released for public comment, usually for a period of 30 days. Once the comments are received, APHIS reviews and responds to the comments, and issues the final EA and accompanying Finding of No Significant Impact (FONSI). A month later, the permit is issued to remove the biocontrol agent form containment and release it into the environment.


While APHIS normally waits for FWS approval before beginning the NEPA review – because APHIS cannot complete the FONSI until it receives FWS concurrence – staff are now considering ways to speed up the process.


This already lengthy process has been further hampered by retirement of key staff in both APHIS and the FWS. New staff were also probably more cautious about approving agents because of the controversy over the potential impact of biocontrol agents’ success in reducing populations of tamarisk (Tamarix spp.) on nesting habitat for the endangered southwest willow flycatcher.


Finally, the process itself causes delays. Petitioners are required to re-submit their proposal to the Technical Advisory Group each time it is revised to address a question raised by a reviewer. These requirements can cause delay and probably frustrate the petitioners.

Current status of weed biocontrol programs

air potato

air potato; Rebekah D. Wallace, University of Georgia; bugwood.org

The current status of weed biocontrol is partially revealed at this site, which shows the status of TAG and APHIS actions.  Some 36 biocontrol agents proposed for field release have been reviewed by the TAG since 2010.  Of these, two have completed the review process and been approved by APHIS for release: agents targeting hawkweeds (Hieraculum spp.) and air potato (Dioscorea bulbifera). Both were approved in 2011. In his presentation, Dr. Tichenor said a third insect – a gall fly targeting Cape Ivy (Delairea odorata) – received a permit allowing release into the environment in May 2016.

The 33 other biocontrol agents that were approved by the TAG are still in other stages of the approval process. Dr. Tichenor reported that an environmental assessment is now being written for a leaf mining fly (Lasioptera donacis) intended to control Arundo (this agent was approved by the TAG only in April 2016 – remarkable speed in obtaining FWS clearance). Three agents are nearing the end of the Endangered Species Act §7 consultation process; these are agents targeting yellow toadflax (Linaria vulgaris), hoary cress (Lepidium draba), and the two swallow-worts (Cynanchum louiseae or Vincetoxicum nigrum; and Cynanchum rossicum or Vincetoxicum rossicum). APHIS has asked for additional information on two agents – targeting gorse and several knotweed species.

One agent intended for use against garlic mustard was rejected by the TAG in 2009.  A second agent is still under review by the TAG.

The other four species approved by the TAG in 2016 to date are presumably at the early stage of the biological assessment; these include two agents for Brazilian pepper, a beetle for Chinese tallowtree, and another insect targeting hawkweeds (genus now given as Pilosella).


Since 2010, the TAG has recommended against field release for eight proposed biocontrol agents.  These included species intended to control Chinese privet (Ligustrum sinense), Russian thistle (Salsola tragus), and Russian knapweed (Rhaponticum repens).  The TAG asked for additional information on four species.


Of course, garlic mustard and Chinese privet are among the top five most frequently detected invaders in the forest inventory study – garlic mustard in the Mid-Atlantic and Northeast, privet in the Southeast.

A fungus (Verticillium nonalfalfae ) is under study as a biocontrol agent for another widespread invasive plant, Ailanthus (tree of heaven). Research by USDA Forest Service scientists have found that a few native species of shrubs and trees are also mildly sensitive to the fungus.  Testing of additional native and agricultural species continues. The fungus occurs naturally in North America so it is not subject to the approval process described here.


An introduced insect, spotted lanternfly (Lycorma delicatula) also attacks Ailanthus. The lanternfly attacks a wide range of woody plants, including grapes and fruit trees. Consequently, Pennsylvania is attempting to eradicate it from the four counties in the eastern part of the state where it has been found.


Hundreds of invasive plant species are damaging ecosystems across the country. Biocontrol is one of the few tools available to counter the threat from invasive species – plants and others. I hope people concerned about invasive species will increase efforts to identify those bioinvaders for which biocontrol appears to offer promise, then to seek out potential biocontrol agents. And that regulatory bodies improve their ability to evaluate proposals promptly – while still being thorough. Doing nothing causes real harm.


Posed by Faith Campbell

What Happens When Decision-Makers (= politicians) Don’t Hear from Us

Decisions and delays that undermine vital phytosanitary programs …


champion green ashchampion dead

Michigan’s champion green ash – before and after emerald ash borer entered the state


Sometimes, when a shipment arriving at a U.S. port is found to be enclosed in wood packaging that is infested by pests, the importers complain to top-level officials. Sometimes, those officials respond to the pressure by allowing that shipment to enter the country – contrary to policy and common sense.

I learned recently of a particularly upsetting situation. A shipment of car parts arrived at a seaport. The wood packaging was found to be infested by a wood-boring insect that attacks pines and possibly other conifers. Because adults were present, the shipment could not be fumigated – because adult insects can escape during that process.

According to U.S. regulations, the shipment should have been refused entry to the U.S. and placed back on the ship to be transported elsewhere.

But what happened instead? The importer – a major auto manufacturer – complained to Michigan political leaders that delay in receiving the “just in time” shipment would result in halting production and unemployment.

Michigan governor Snyder and both Senator Debbie Stabenow and Senator Gary Peters put pressure on the U.S. Secretaries of Agriculture (who supervises APHIS) and Homeland Security (who supervises the Bureau of Customs and Border Protection). The two secretaries agreed to allow movement of the pest-infested shipment from the seaport across half the country to Michigan. They overruled their staffs and endangered our forests – most immediately along the shipment route. Those forests provide wildlife habitat, carbon sequestration, water supplies and other ecosystem serves; as well as numerous jobs and industries. It will be years before we know whether pests escaped the containers during transport and established in any of the wildland, rural, or urban forests along the route.

Had the shipment been refused entry — as the law requires — a new shipment in pest-free crates would have arrived within weeks.

It is particularly ironic that this pressure was exerted by Michigan officials. You would think that Michigan officials would remember the devastation to their state caused by the emerald ash borer and —  instead — press for vigorous enforcement of effective phytosanitary rules.

Of course, the Federal officials responsible for protecting our Nation from damaging plant pests should be strong in the face of political pressure. They should enforce regulations adopted through the appropriate regulatory processes. However, in this case, they chose the politically expedient action instead of carrying out their legal responsibilities.

A second example:

Since 2010, APHIS and its Canadian counterpart, Canadian Food Inspection Agency, have tried to amend the two countries’ regulations to require that wood packaging used to support or contain goods traded between the two countries conform to the international standard (ISPM#15). (When they initially adopted ISPM#15 in 2004, the U.S. and Canada exempted their bilateral trade.)

Why end this exemption? Both countries realize that each country harbors pests – native or introduced – that could pose a threat to forests in the other country. Also, the exemption complicates enforcement of the standard for shipments that originated elsewhere, e.g., in Europe or Asia.

For example, shipments of Italian decorative tiles that had been held in Canadian warehouses have been sent later to retailers in the U.S. Shippers have claimed that the pallets supporting the tiles are of Canadian origin, so they don’t need to have the stamp certifying treatment. Customs officials say that sometimes the evidence counters this claim – leading them to conclude that the pallet actually accompanied the load of tiles throughout its movement from Italy and thus is in violation of both U.S. and Canadian rules.  I expect that Canadians could cite examples of the same problem arising with shipments from U.S. warehouses to Canadian retailers.

Still, despite the need to end the exemption, APHIS’ proposed rule has been stuck at higher levels in the Department of Agriculture due to opposition by the Chamber of Commerce and some business associations.

Why are top-level politicians and other officials undermining phytosanitary programs? Do they not know the costs they’re risking?

I think it is at least partly because those of who know about the pest risk associated with wood packaging lack powerful and vocal allies who can educate the policy-makers about the damaged caused by introduced tree-killing pests.

For a reminder – woodborers have been estimated by Aukema et al. 2011 to cost local governments $1.7 billion per year; homeowners pay another $760 million to remove dead trees from their property. For more information, see also my blogs posted in July, August, September, and October 2016; fact sheets posted here and articles by Aukema et al. 2011 and Lovett et al. 2016. Remember that the costs discussed in these papers don’t reflect the vast majority of environmental and ecosystem losses, including disruption of such unique ecosystems as black ash swamps from New Brunswick to Minnesota and tree hammocks in the Everglades. Nor do they include the losses of cultural resources to Native Americans, such as basket weavers of the North and medicinal plants for Tribes in Florida …

You would think that federal and state officials who have lived through the disasters resulting from introduced wood-borers would want strict enforcement of customs and plant health regulations intended to prevent introduction of additional tree-killing pests. But these people respond to what they hear from the public and the media – perhaps the loudest voice they heard most recently. Unfortunately, people who care about invasive species – specifically tree-killing insects and pathogens – don’t have spokespeople.

Do you think the President or even Secretary of Agriculture is hearing about tree-killing pests every week? From whom? Not the Chief of the USDA Forest Service. Not the forest products industry. Not leaders of conservation organizations. Do governors, mayors, or heads of state agriculture or conservation agencies speak to Senators or Members of Congress — routinely and repeatedly — about the need to better protect our forests from non-native pests?

The evidence is that they do not. And what is the result?  These decision-makers respond to pressure from importers who want access to traded goods – and who are quite vocal about their complaints. Politics is how our country makes important decisions. And in politics, the squeaky wheel gets the grease.

When was the last time any of these officials – USDA Secretary Vilsack, DHS Secretary Jeh Johnson, Governor Rick Snyder, Senators Stabenow and Peters – heard from constituents or from leaders of the agencies under their jurisdiction about the importance of preventing introduction of new wood-boring insects?  When did a Michigan news media outlet last publish a report that discussed the pathways or vectors by which these insects enter the country and the importance of enforcing rules adopted to prevent additional introductions?

I recognize that it can be difficult for staff to get the attention of their supervisors on such issues. For example, I have been told by several people that California Governor Jerry Brown was surprised to learn that sudden oak death had killed millions of trees in his state. How did he “learn” this? From an article in the Washington Post that reported on a recent scientific study (Cuniffe et al. 2016).  Staff of CalFire were very frustrated that their efforts to educate the Governor had not resulted in his understanding the pathogen’s impact.

So – what can we do to re-balance the politics of phytosanitary policy – so that our political leaders understand why phytosanitary rules are adopted and support both adoption and enforcement of strong, effective measures?

We need to

  • Speak up at every opportunity about the damage to our trees caused by non-native insects and pathogens and describe the policies and programs that can reduce that damage and the risk of additional introductions.
    1. Tell this story to elected officials at all levels
    2. Write letters to the editors of media outlets
    3. Offer to show officials and reporters examples of the damage
  • Educate members of other stakeholder groups and ask them to integrate this message into their interactions with officials and the media.


  • Election seasons provide opportunities to raise issues.
  • People taking up positions in January (whether elected or appointed) will be more open to learning about “new” issues than have been people who have occupied an office for some time.

Finally – these messages need to be repeated periodically. Proctor and Gamble does not make its profits  by asking us to buy their toothpaste once a year. We cannot duplicate a major corporation’s advertising budget – but we can speak up!



Aukema, J.E., B. Leung, K. Kovacs, C. Chivers, K. O. Britton, J. Englin, S.J. Frankel, R. G. Haight, T. P. Holmes, A. Liebhold, D.G. McCullough, B. Von Holle.. 2011. Economic Impacts of Non-Native Forest Insects in the Continental United States PLoS One September 2011 (Volume 6 Issue 9)

Cunniffe, N.J., R.C. Cobb, R.K. Meentemeyer, D.M. Rizzo, and C.A. Gilligan. Modeling when, where, and how to manage a forest epidemic, motivated by SOD in California. PNAS, May 2016 DOI: 10.1073/pnas.1602153113

Lovett,G.M.,  M. Weiss, A.M. Liebhold, T.P. Holmes, B. Leung, K.F. Lambert, D.A. Orwig, F.T. Campbell, J. Rosenthal, D.G. McCullough, R. Wildova, M.P. Ayres, C.D. Canham, D.R. Foster, S.L. LaDeau, and T. Weldy. 2016. Nonnative forest insects and pathogens in the United States: Impacts and policy options. Ecological Applications, 0(0), 2016, pp. 1–19. DOI 10.1890/15-1176.1


Posted by Faith Campbell