New study evaluates “candidate pool” from which invasive species might come

Campanula latifolia – one of the species detected as an “emerging” invasive species in the database relied upon by the authors of the study

The authors of a new study note that officials managing invasive species programs rely largely on knowledge of a species’ previous invasion history to predict its level of threat in the geographic area under their responsibility. This approach does not work with the many introduced species that have no history of a previous detected invasion. Hanno Seebens and 49 coauthors – including tree-pest experts Eckehard G. Brockerhoff, Marc Kenis, Andrew M. Liebhold, and Alain Roques — have sought to figure out how great a handicap that lack of data is. See “Global rise in emerging alien species results from increased accessibility of new source.” The study is available for $10 here. Figures, tables, and references are available without charge.

The study used a database of 45,984 first records of establishment of 16,019 species belonging to the following major taxonomic groups: vascular plants, mammals, birds, fishes, insects, crustaceans, mollusks, and other invertebrates.

Last year, many of the same scientists, relying on the same database, found that the rate of new introductions of alien species has risen rapidly since about 1800 – and shows no sign of slowing down. The adoption of national and international biosecurity measures during the 20th century have slowed introductions – but they are not sufficiently effective, especially regarding those plants and animals that are introduced primarily accidentally as stowaways on transport vectors or contaminants of commodities (e.g., algae, insects, crustaceans, mollusks and other invertebrates). The 2017 study found a strong correlation between these “accidental” alien species’ spread and the market value of goods imported into the region of interest. For that study, go here.  I blogged about the findings on 1 March 2017 – here.

In the new 2018 article, the scientists found that even after many centuries of invasions the rate of emerging alien species is still high. Across all taxonomic groups, one out of four detections during 2000 – 2005 was of a species that had not been previously recorded anywhere as alien. Detections of “new” or “emerging” aliens is occurring at an even higher rate for some taxonomic groups. But new detections of insects fit the average – every fourth detection during 2000 – 2005 was of a species not previously recorded outside its native range.

The authors conclude that the continuing high proportion of “emerging” alien species is best explained by the interplay of 1) the incorporation into the pool of potential alien species of species native to regions formerly not accessible to traders; 2) increases in introduction rates due to higher import volumes; and 3) probably rising establishment rates as a consequence of land degradation that facilitates establishment in recipient regions. This process compensates for the decrease of new invaders from historically important source regions – from which potentially invasive species have presumably already taken advantage of pathways and been recorded as introduced somewhere.

emerald ash borer Agrilus planipennis – one of the species in the database of “emerging” invasive species

 

The number of insect species in the database candidate species pool is 20,611 species – an admittedly small fraction of all insects (for example, there are more than 350,000 beetle species worldwide). Twenty-four percent of these insect species have already been established somewhere outside their native ranges. However, the authors note that data gaps – which are larger for some taxonomic groups and geographic regions – mean that the number of actual “first” introductions is probably larger than records indicate, and consequently the estimated size of the candidate species pools may also be higher. Indeed, the paper does not attempt to estimate the actual size of the invasive species “pool” for insects.

The authors analyzed the importance of eight factors – temperature, relative humidity, import values, three land-use categories, number of botanical gardens, and human population size – in explaining the continued high number of “emerging” invaders detected in recent years. While these factors were explanatory for some taxonomic groups, they had a very low predictive value for insects.

For vascular plants, every third record of an introduction in 2000 – 2005 was of an “emerging” alien  species. Interestingly, the number of botanical gardens in a country was a significant predictor for emerging alien vascular plants. However, as the authors of the article point out, reliance on this factor ignores the probable importance of other contributors such as the number of species planted in the receiving country; similarities between source and receiving environments; and introductions by acclimatization societies, European explorers or settlers, and plant hunters.

Acer ginnala –one of the species detected as an “emerging” invasive species in the database; photo by J. Weisenhorn, University of Minnesota extension

In any case, lots of previously undetected alien species are detected each year. In this database, 58% of the species had a single record; 86% of all species have no more than two first records in countries on the same continent. The large number of species with only one or two records led the authors to conclude that most species will not spread widely. I question that conclusion because species often require some time to spread to new locations – either local or distant. The authors do admit that they are unable to determine which species have a high potential for spread.

ash trees at the St. Louis arch – before arrival of emerald ash borer

 

The continued high rate of introduction of new species leads the authors to estimate that between 1% and 16% of all species on Earth – depending on the taxonomic group – qualify as potential invasive alien species. The authors did not attempt to estimate the true candidate pool or percentage of invasive species for insects. For vascular plants, the authors estimated the candidate pool at 47,000 species (out of a total of 368,000 species on Earth), or 13%.

Like its predecessor, this study’s importance arises from its broad perspective – covering the entire globe and a wide range of taxonomic groups. Its major conclusion that invasions will continue on a large scale serves as a warning to all stakeholders. These include officials charged with protecting agriculture and the broader economy, or the natural environment; conservationists; and those engaged in the economic activities that promote invasion.

However, the authors found that the data did not support more specific advice. First, as noted above, they were unable to determine which of the “emerging” invasive species in all taxonomic groups have a high potential to spread.

For those of us focused on invasive species that threaten native plants, data gaps limit the predictive value of the study the most. The database is too scant even to estimate the invasive species “pool” of potential insect pests. Plant pathogens are not included in the analysis.

 

 

Posted by Faith Campbell and Phyllis Windle

 

We welcome comments that supplement or correct factual information, suggest new approaches, or promote thoughtful consideration. We post comments that disagree with us — but not those we judge to be not civil or inflammatory.

 

 

You Might Be Surprised By Who is Authorized to Manage Wildlife on Federal Lands

mountain goats – introduced onto USFS-managed lands in the Columbia River Gorge at state initiative; in Utah, the state introduced mountain goats on lands adjacent to a USFS Research Natural Area

 

The journal Environmental Law has just published a 135-page article that debunks a common myth of wildlife management – a piece that the U.S. Forest Service tried to quash. The authors’ analysis could affect the introduction of potentially invasive non-native species – and the reintroduction of native ones – on federal lands.

Nie, M., C. Barns, J. Haber, J. Joly, K. Pitt & S. Zellmer. 2017. Fish and Wildlife Management on Federal Lands; debunking state supremacy. Environmental Law, Vol. 47, no. 4 (2017).

The article reviews the legal authority of federal and state governments to manage wildlife on federal lands.  The authors examined wildlife-related provisions within the National Park System, National Wildlife Refuge System, National Forest System, Bureau of Land Management, the special case of Alaska, the National Wilderness Preservation System, and the Endangered Species Act. They also reviewed cases where federal and state agencies came into conflict over wildlife management on federal lands.

Citing the U.S. Constitution, federal land laws, and relevant case law, the authors assert that federal agencies have an obligation, not just the discretion, to manage and conserve fish and wildlife on lands and waters under their management. They say that the often-cited statement that “the states manage wildlife and federal land agencies only manage wildlife habitat” is wrong from a legal standpoint. This is the myth that the article debunks.

Furthermore, the authors find that federal agencies frequently apply their powers in an inconsistent and sometimes even unlawful fashion. Due to political pressures, they may back down when confronted by states wanting to manage wildlife to achieve their own goals – even when the state’s goals conflict with the legally-mandated purposes of the federal land under question. Such goals might include ensuring maximum populations of “game” animals or introduction of species to new habitats – regardless of the potential impact on native plants and animals.

The authors note that federal land and wildlife laws provide ample opportunities for constructive intergovernmental cooperation in wildlife management. They call for truly mutual collaboration by federal, state, and tribal authorities in managing wildlife. However, such cooperation is blocked in part by states choosing to challenge the constitutional powers, federal land laws, and U.S. government supremacy. In addition, the authors contend, most states have not put together programs that address their own conservation obligations. These obligations are inherent in the widely recognized doctrine of wildlife being a public trust to be managed for the present and future benefit of the people, not the government or private individuals.

According to the website of the Forest Service Employees for Environmental Ethics,  posting of a draft of this article on the University of Montana website (where lead author Martin Nie teaches) led the U.S. Forest Service to pressure the university to withdraw the article. The university refused, and the Forest Service ended its contract with Nie and his research center.

The paper can be downloaded here. We welcome comments that supplement or correct factual information, suggest new approaches, or promote thoughtful consideration. We post comments that disagree with us — but not those we judge to be not civil or inflammatory.

Posted by Faith Campbell

“Invasive Species Denialism” Increases Exponentially

 

Anthony Ricciardi and Rachael Ryan have analyzed 77 articles published from 1994 to 2016 in scholarly journals and the mainstream media that express some level of “invasive species denialism”. Denialist articles appearing in these publications have increased exponentially over the past three decades, most notably in the mainstream popular press – and they have the graph, fitted to a curve, to prove it.

The authors cite Diethelm and McKee (2009) in defining “science denialism” as “the use of rhetorical arguments to give the appearance of legitimate debate where there is none, with the ultimate goal of casting doubt on scientific consensus.” Similar strategies have appeared in disputes over the dangers of tobacco smoking and climate change.

Ricciardi and Ryan say that “[u]nlike normal scientific debates, which are evidence based, this discourse typically uses rhetorical arguments to disregard, misrepresent or reject evidence in attempt to cast doubt on the scientific consensus that species introductions pose significant risks to biological diversity and ecosystems….” In their view, the “denialist” articles assert an absence of damage from bioinvasion “despite peer-reviewed research that shows otherwise ….”  One example of evidence ignored by the contrarians are several analyses of the causes of endangerment or extinction of vertebrate species listed on the Red List maintained by the IUCN [as reported in my blog from May 2016 link]

Furthermore, these claims are almost always made in the absence of peer review – either in popular media or as opinion articles in scholarly journals. Many of the writers are social scientists and philosophers, not natural scientists. Only five of the 77 articles, or 6%, were published in natural science journals.

Ricciardi and Ryan say that unlike genuine scientific debate, “denialists” reject scientific evidence while repeating claims that have already been refuted in the scientific arena. Often, “contrarians” link invasion biology to xenophobia and latent racism, or otherwise impugn the motives of those engaged in the invasion biology field.

Ricciardi and Ryan consider possible reasons for the rise in “denialist” articles. Possible reasons include anti-regulatory ideologies, distrust of scientific institutions, conflicting values and perceptions of nature, even individuals’ desire for attention. They note that despite the absence of a true scientific controversy, the “denialists’” assertions gain credibility because science reporters think they need to present “both sides” of the argument.

Unlike the situation in the contrived controversies over climate change and risks from tobacco, we at CISP have not found a powerful industry backing the contrarians.

Ricciardi and Ryan express concern that the growing number of articles rejecting decades of research on invasive species might undermine policy initiatives at a time when invasion biology’s relevance to biosecurity, conservation, and ecosystem management is increasing. Gaining public support is critical to the success of such policies.

This concern is especially well-founded given that the authors’ results underestimate the extent of invasive species denialism. That is, they omitted from their analysis articles from internet blogs – known to be major platforms for promoting “science denialisms” – and websites that specifically attack invasion biology.

While Ricciardi and Ryan published this as a “note,” it is packed with information, e.g., references on science denialism, in general; and, in supplementary information, a table citing the 77 denialist articles.

 

SOURCE

INVASION NOTE. Ricciardi, A. & R. Ryan The exponential growth of invasive species denialism. Biological Invasions. Published online 12 September 2017

 

New Disease that Attacks Beech is Spreading

beech leaf disease symptoms;  photo by John Pogacnik, Lake Metroparks

In 2012, Ohio authorities detected a new disease attacking American beech (Fagus grandifolia) in northeast Ohio. The disease has spread to several counties in northeast Ohio and neighboring areas of Pennsylvania, New York, and Ontario.

Counties currently reporting beech leaf disease; Cleveland Plain Dealer relying on data from Ohio Department of Natural Resources

Currently, no cause has been determined – despite efforts by the USDA Forest service, Ohio Division of Forestry, Ohio Department of Agriculture, Holden Arboretum, and Ohio State University.

Early symptoms are dark striping on the leaves – best seen by looking upward into the backlit canopy. The striping is formed by a darkening and thickening of leaf tissue between leaf veins. Later, lighter, chlorotic striping may also occur. Both fully mature and very young “emerging” leaves show symptoms. Eventually the affected foliage withers, dries, and yellows. Bud and leaf production is also affected. However, there is little premature leaf loss.

All ages and sizes of beech are affected. Sapling and pole-sized trees die within about three years after symptoms are observed. In areas where the disease is established, the proportion of American beech affected nears 100%.

Disease incidence does not appear to be influenced by slope, aspect, or soil conditions. Also, while a wide variety of insects and pathogens is associated with symptomatic trees, these appear to be separate from and unrelated to beech leaf disease.

The disease might also affect European and Asian beech.

Given the range and ecological importance of American beech – a species already under threat in from beech bark disease – scientists seek to form a collaborative group that would efficiently address research issues related to the cause of this malady and management implications for the species.

Beech trees in the Northeast, Appalachians, and even Michigan are already under threat from beech bark disease, described here .

Workshop to Coordinate Research and Management

A workshop will take place May 2-3, 2018 at Cleveland Metroparks Watershed Stewardship Center, 2277 West Ridgewood Drive, Parma, OH 44134

https://clevelandmetroparks.com/parks/visit/parks/west-creek-reservation/watershed-stewardship-center-at-west-creek

Presentations on the first day of the meeting would seek to

  1. Prioritize next steps and coordinate efforts.
  2. Increase communication and coordination among land managers and researchers.
  3. Inform resource allocation and leverage funding sources for maximum effectiveness.
  4. Set up 5-year plan – Research, Survey, Diagnostics, etc.

The second day would include a field trip to view the disease.

Contact one of the following if you are interested in giving a presentation on the ecological importance of beech; or the history, etiology, surveys, or epidemiology of beech leaf disease.

healthy beech in Virginia; F.T. Campbell

SOURCES

http://portal.treebuzz.com/beech-tree-leaf-disease-no-known-cause-1036

John Pogacnik, Biologist, Lake Metroparks & Tom Macy, Forest Health Program Administrator, Ohio Department of Natural Resources Division of Forestry. Forest Health Pest Alert Beech Leaf Disease July 2016

 

New Woodborer Detected – Importance of Surveillance By-Catch

 

Agrilus smaragdifrons – photo by Ryan Rieder, New Jersey Department of Agriculture

 

At least 11 non-native metallic wood-boring beetles in the genus Agrilus  have been introduced to either the United States or Canada – or both. The most recent detection is Agrilus smaragdifrons Ganglbauer, which feeds on the invasive plant tree of heaven (Ailanthus altissima). This information comes largely from an important new paper by noted entomologist E. Richard Hoebeke at the University of Georgia and others (see the reference Hoebeke et al. 2017 at the end of this blog).

 

Two more Agrilus species that are native to Mexico and – in one case, also Arizona – have been introduced to separate parts of the U.S. and are killing naïve hosts there. These are A. prionus (which attacks soapberry trees in Texas) and A. auroguttatus (the goldspotted oak borer, which attacks several oak trees in California). Both species are described here

 

The genus Agrilus is considered to be the largest genus of the entire Animal Kingdom; it has over 3,000 valid species (Hoebeke et al. 2017).

 

Most of the Agrilus introduced to North America do not attack trees. Several attack crops such as grapes, currants and gooseberries, and rasberries (Hoebeke et al. 2017; (Jendek and Grebennikov 2009; reference at the end of the blog). Others attack horticultural plants including roses, wisteria, and mimosa (Jendek and Grebennikov 2009).

 

Still others attack plants that are invasive, such as honeysuckles (Lonicera spp). One, A. hyperici Creutzer, was deliberately introduced as a biocontrol agent targeting St. John’s wort (Hypericum perforatum L.) (Jendek and Grebennikov 2009).

 

However, Agrilus sulcicollis attacks oaks, beech, chestnut and other trees in the Fagaceae family in its native Europe. The beetle was detected in Ontario in 2006 (Jendek and Grebennikov 2009).

 

The most recently detected East Asian “jewel” beetle, Agrilus smaragdifrons, was discovered by analysis of Agrilus species caught in surveillance programs targeting other species – usually emerald ash borer (EAB) (A. planipennis). The beetle was first identified in traps deployed by the New Jersey Department of Agriculture. Unlike in many trapping programs, New Jersey screened the trap catches for all beetles in the family Buprestidae (which includes EAB). In 2015, two samples from separate trapping sites in the state contained a distinct but unrecognized species. These were identified by Dr. Hoebeke as the East Asian A. smaragdifrons (Hoebeke et al. 2017).

 

Alerted to the new species, scientists conferred and found additional detections of the species. An EAB biosurveillance program in New England utilizing the native ground-nesting wasp Cerceris fumipennis also detected the A. smaragdifrons in at least one location in central Connecticut in 2015. (The wasps capture beetles in the Buprestid family to feed to their young. By observing which species of beetles are brought to their nests by the wasps, scientists can learn which species are present in an area.)

 

Pennsylvania has collected A. smaragdifrons in surveillance programs targeting either EAB or spotted lantern fly (Lycorma delicatula (White))(Hoebeke et al. 2017).

locations where A. smaragdifrons has been detected; map from Hoebeke et al. 2017

It turned out that A. smaragdifrons has been in the U.S. for several years. One scientist photographed the beetle – without knowing what it was – in 2011 in New Jersey and posted the image at BugGuide (http://bugguide.net/node/view/1139674/bgimage ; accessed by Hoebeke and colleagues on 1 May 2017).

 

Recent field observations in China and the U.S. have observed both adults and larvae feeding on tree of heaven. In Beijing, many Ailanthus trees in gardens or along roadsides have succumbed to attack by this wood-borer. Other tree species on the grounds of Beijing Forestry University have not been attacked by A. smaragdifrons (Hoebeke et al. 2017). Still, no proper host-specificity test has yet been conducted on the beetle.

 

Of course, Ailanthus is widespread across North America, from southern Canada to Florida, and even along river courses in the arid Southwest. According to the USDA Forest Service (see the third on-line reference at the end of the blog), Ailanthus is known to be present in 42 states. It is most abundant in the Mid-Atlantic and Northeastern states. For example, 18% of the forest plots inventoried by the USDA Forest Service Forest Inventory Analysis program in West Virginia had Ailanthus present. Efforts are under way to try to find biocontrol agents (Hoebeke et al. 2017).

 

 

Importance of analyzing by-catch in insect detection surveys.

 

While most managers of pest surveys ignore the non-target species caught in their traps (“by-catch”), this detection shows that examining the by-catch can sometimes result in discovering previously unknown species. (Other examples of such detections include the pine pest Sirex noctilio in New York in 2004 and the oak-feeding Agrilus sulcicollis in Ontario and later Michigan.

 

Hoebeke and his colleagues strongly recommend that scientists pay attention to non-target insects captured in their surveys, especially those insects that show up in any abundance for the first time.

 

SOURCES

 

Hoebeke, E.R., E. Jendek, J.E. Zablotny, R. Rieder, R. Yoo, V.V. Grebennikov and L. Ren. 2017. First North American Records of the East Asian Metallic Wood-Boring Beetle Agrilus smaragdifrons Ganglbauer (Coleoptera: Buprestidae: Agrilinae), a Specialist on Tree of Heaven (Ailanthus altissima, Simaroubaceae) Proceedings of the Entomological Society of Washington, 119(3):408-422.

 

This article demonstrates how to distinguish the Ailanthus beetle from other Agrilus species.

 

Jendek, E. and V.V. Grebennikov. 2009. Agrilus sulcicollis (Coleoptera: Buprestidae), a new alien species in North America. Canadian Entomologist 141: 236–245.

Maryland has declared A. smaragdifrons its “invasive species of the month” for December 2017. Visit http://mdinvasivesp.org/invader_of_the_month.html

Information about Ailanthus as an invasive plant is available at

https://www.invasivespeciesinfo.gov/plants/treeheaven.shtml ; https://www.nps.gov/plants/alien/pubs/midatlantic/midatlantic.pdf

https://www.nrs.fs.fed.us/pubs/43136

Biological Control Approved for Invasive Black and Pale Swallow-wort!

black swallow-wort; photo by Leslie J. Mehrhoff, University of Connecticut

Help is on the way!

With funding support through the Northeast IPM Partnership, University of Rhode Island entomologist Richard Casagrande has been leading a team to find biological control agents for two invasive plant species. The target species, black swallow-wort (Vincetoxicum nigrum) and pale swallow-wort (Vincetoxicum rossicum), are native to Europe and members of the milkweed family Apocynaceae (previously Asclepiadaceae). In the U.S., their vigorous growth overtakes and smothers small trees, shrubs and other native plants and threatens the survival of the monarch butterfly whose larvae rely on milkweed for their development. They are currently found in the northeastern and mid-Atlantic states but could spread much farther.

(See Faith’s earlier blog about USDA speeding up approvals of biocontrols for invasive plants here.

U.S. native swallow-wort species belong to the genus Cynanchum and include a dozen or so rare and endangered plant species. It was essential to consider these native species in the investigations. Feeding tests would need to show definitively that the potential biocontrol species would not attack native swallow-worts or other native members of the milkweed family. And, Jennifer Dacey, Casagrande’s graduate student, wanted to find out how well the exotic swallow-worts might provide for monarch butterflies. The results were alarming.  All of the monarch larvae died when hatching on black swallow-wort.  “They stopped eating after a single bite,” says Casagrande.

pale swallow-wort; photo by Leslie J. Mehrhoff, University of Connecticut

Why biological control?

Small infestations of invasive swallow-wort, seedlings and young plants can be pulled up by hand, mature plants can be dug up, and frequent mowing can suppress populations in fields. However, most infestations are too extensive to control by hand. Systemic herbicides – those that are carried through the plant to the roots — can be used to control large infestations, using foliar sprays. Several years of treatment will likely be needed due to the persistence of swallow-wort seeds. These efforts can be part of an overall Integrated Pest Management strategy but the best long-range solution is biological control. Biocontrol relies on finding herbivores that have coevolved to feed on specific invasive plants in their native range that will not have a significant impact on non-target species. Graduate student Aaron Weed worked with Swiss scientists to identify a handful of specialist plant herbivores, mainly beetles and moths that evolved with black swallow-wort and pale swallow-wort in their native ranges in Europe and were highly unlikely to feed on other plant species.

Approval process.

All biological control agents must be approved for release by the U.S. Department of Agriculture, Animal and Plant Health Inspection Service (APHIS). APHIS sets up a Technical Advisory Group, or “TAG”, to review the research on feeding tests conducted by the researchers, called “no-choice” tests.  Potential biocontrol agents are tested for feeding on an extensive selection of native plant species and their relatives to ensure the agents are specific to the target species and won’t pose a threat to agriculture or to rare, threatened or endangered species or to other native species. The TAG list includes, naturally, most native milkweed relatives and even species more distantly related.

“Luckily, none of our native plants is closely related to the [invasive]swallow-worts,” says Casagrande. “That makes [swallow-wort] a great candidate for classical biological control.  The Tag list also includes a suite of Eurasian plants you might expect these specialists to nibble at now and then, and even plants that could host these specialists’ relatives. The bar is high for these no-choice tests: biocontrols must prove they’ll die before they switch.”

Casagrande’s team examined five possible biocontrol specialists in their quarantine lab, including two European moth species (Hypena opulenta and Abrostola asclepiadis) that feed on swallow-wort leaves in their native range. The researchers wanted to be sure these insects wouldn’t jump to non-target plants on the TAG list, since the last thing anyone wants is a new pest dominating the landscape, threatening agriculture, native ecosystems, and rare plants.

Results?

Both leaf-eating moths “passed the acid test,” says Casagrande. However, scientists have only petitioned for and received approval for Hypena opulenta, which was approved by the USDA in September 2017. They may seek approval for Abrostela in the future but for now are focused on rearing, releasing, and studying the effectiveness of Hypena.  Releases in Canada started in 2013 when Hypena was approved there. Since then, it has established and spread but it is too soon to evaluate its effectiveness.

Releases in the U.S.

Hypena opulenta was released on Naushon Island, Massachusetts, in early September 2017 – the only release in the United States – where both black and pale swallow-wort occur. The field release was carried out by placing about 400 larvae in each of 4 large cages containing both swallow-wort species in sun and shade locations. The larvae will be allowed to grow and develop in the cages for a little while before the cages are opened to allow the larvae to escape and start establishing on the island.

Next steps?

Funding will be sought to support rearing of Hypena at University of Rhode Island and other locations in the U.S. Dr. Lisa Tewksbury, Manager of Biological Control at URI, is running the program. It will take a few years to get to the point of having sufficient moths to distribute widely.  Best practices for releasing and monitoring will be developed.

Thanks to the Northeast IPM Partnership and the interest and dedicated efforts of Casagrande and his research team, we now have the most effective tool to use against two highly invasive plant species that will also protect our native species and natural ecosystems.

 

Posted by Jil Swearingen

Jil recently retired from the federal government and works as an invasive species consultant. She has 28 years of experience working on invasive species at the county, regional and national level in areas of education, outreach and management. Jil initiated and co-founded the Mid Atlantic Invasive Plant Council and serves on the board. Jil serves as the Coordinator for the Mid Atlantic Early Detection Network, a project she initiated and co-developed, and she continues to serve as Chair for the Plant Conservation Alliance’s Alien Plant Working Group and manager of the Weeds Gone Wild website. Jil is lead author of the book, Plant Invaders of Mid-Atlantic Natural Areas. She was recently elected to serve on the Board of Directors of the Maryland Native Plant Society

 

We welcome comments that supplement or correct factual information, suggest new approaches, or promote thoughtful consideration. We post comments that disagree with us — but not those we judge to be not civil or inflammatory.

 

Worldwide Study Confirms ISPM#15 is not Protecting Forests – What Do We Do Now About Pests in Wood Packaging?

 

You know that the continuing pest risk associated with imports of wood packaging is among my biggest concerns. See, for example, fact sheets here and blogs here and here.

A new book about the family Cerambycidae (edited by Wang 2017; reference at end of blog) confirms that longhorned beetles continue to be introduced to many countries via this pathway, more than a decade after widespread implementation of the international standard governing wood packaging (ISPM#15). Furthermore, data from several countries confirm that China continues to fall short … but that problems are more widespread.

The Wang book finds that 16 outbreaks of the Asian longhorned beetle (ALB) were detected between 2012 and 2015.

Unless otherwise noted, the information provided here comes largely from the book’s chapter on biosecurity coauthored by Dominic Eyre and Robert A. Haack (see link below). Opinions stated are mine, unless specified otherwise.

In some cases – which I will note – further details are from my earlier posts.

While I think the risk of introduction of highly damaging pests via the wood packaging pathway is well documented in Wang (2017) and other publications, no one can truly quantify this risk because of shortcomings in countries’ data. Available data come primarily from countries’ records of pest “interceptions” – usually at points of entry.  However, interception data are inadequate to conclusively establish the lack of a threat for a particular trade or to provide a fair comparison of the relative threat of particular trades. Most interception databases have the following shortcomings (Eyre and Haack are summarizing points made by a third scientist – Lee Humble – in an earlier article):

(1) interception databases are not based on random sampling, which is necessary to measure the “approach” or “infestation” rate;

(2) inspections which find no pests are not recorded, so we cannot know what proportion of incoming shipments are infested;

(3) once inspectors have discovered a quarantine pest in a shipment, the consignments may be destroyed without further inspection, and thus other exotic organisms can be missed;

(4) only a small percentage of individual shipments are inspected; and

(5) organisms often are not identified to species due to difficulty of identifying larvae.

Furthermore,

(1) trade volumes and sources can change rapidly;

(2) the number of consignments inspected varies from year to year in response to national and regional plant health and wider government priorities;

(3) the method and intensity of quarantine inspections can vary within and among countries and as well as over time; and

(4) different proportions of consignments from different trades can be inspected, reflecting the perceived quarantine risks of each trade.

Still, scientists try to analyze the available data because propagule pressure may be the most important factor in determining whether an exotic pest becomes established.

What have they found?

Data from both the United States and Europe document that problems of non-compliance continue in recent years – more than a decade after adoption of ISPM#15.

United States:

  • Since APHIS interception records began being computerized in 1985, Cerambycidae have been among the most frequently intercepted insect families associated with wood products and packaging. The top five countries for infested shipments during the period 1984 – 2008 were China, Italy, Mexico, Turkey and Spain. A country’s rank is linked in part to import volumes – which are very high for China, Canada, and Mexico. Because the  U.S. inspects very limited quantities of wood packaging from Canada, its absence from the top five may be misleading [discussed in my blog from February, here.

Another factor explaining these countries’ rankings is the continued – in fact increasing! – presence of pests in wood packaging accompanying imports of tile and quarry products (e.g., marble, slate). Many of these imports are from Italy, Spain, and Mexico. Interceptions on these imports increased significantly from the mid-1990s to 2008. The increase in these interceptions is most alarming because it shows USDA leaders have not yet taken effective action to curtail this risk, despite its being evident since record-keeping began.

 

  • Over the period Fiscal Years 2010 through 2016, the U.S. Bureau of Customs and Border Protection has detected nearly 5,000 consignments in which cases the wood packaging harbored a pest in a regulated taxonomic group. APHIS experts identified 2,500 insects taken from wood packaging during this period; a quarter were Cerambycids. A second APHIS analysis of a subset of the wood packaging-associated insects found examples from 39 countries, including 212 shipments from Europe; 130 shipments from Asia; and 341 shipments from the Americas – almost exclusively Mexico. [These detections are discussed in my blog from February, here.

 

Europe has had a similar experience.

  • Interception records included in EUROPHYT show 306 Cerambycidae interceptions on wood packaging over the period 1998 – 2013. The number of interceptions recorded in 2012 and 2013 are double those of all previous years. Each year, the majority are on wood packaging from China.
  • Most interceptions of ALB (distinct from detections of establishments) have occurred after the shipment cleared border inspection procedures, e.g., in warehouses.
  • As with the U.S., while the majority of non-compliant shipments are from China, the problem is worldwide: Europe has also found various species of longhorned beetles in wood packaging from various European countries (inside and outside the European Union), other Asian countries, Africa, Australasia, and the Americas.
  • Austria inspected 451 consignments of stone imports received April 1, 2013 – April 14, 2014. Forty-four consignments (9.8%) were found to be out of compliance with ISPM#15. Live Cerambycidae were found in 38 consignments (8%), including ALB. This finding confirms the widespread awareness that stone imports rank high for non-compliant wood packaging.

 

Regulatory Authorities’ Response (or lack thereof)

Europe

  • Since March 31, 2013, the European Union has required inspection of 90% of consignments of slate, marble, and granite and 15% of consignments of two other categories of stone imports.

CBP agriculture specialists in Laredo, Texas, examine a wooden pallet for signs of insect infestation. [Note presence of an apparent ISPM stamp on the side of the pallet] Photo by Rick Pauza
United States

  • As noted by Haack et al. (2014) (reference below), as of 2009, approximately 13,000 containers harboring pests probably enter the U.S. each year. That is 35 potential pest arrivals each day. [This issue is also discussed in the fact sheet and blogs here and here.
  • The United States has not specified an obligatory inspection rate for such high-risk imports as stone and tile. Instead, it relies on Customs and Border Protection to target import shipments suspected of being out of compliance based on past performance of importers, suppliers, and types of imports.
  • Several relevant issues are discussed in the blog in February 2017 (second blog linked to above). First, I noted that the U.S. Department of Homeland Security Bureau of Customs and Border Protection – over the seven-year period Fiscal Years 2010 through 2016 – has detected nearly 5,000 cases of wood packaging harboring a pest in a regulated taxonomic group. Comparing the estimate by Haack et al. 2014 with the CBP data indicates that Customs is detecting about 6% of all pest-infested shipments.
  • Furthermore, about 26% of infested wood pieces detected by CBP were found in wood that was marked as having been treated according to ISPM#15 requirements. What does this mean? Fraud? Accidental misapplication of the treatments? Or are the treatments less effective than hoped? What are USDA and other responsible agencies doing to clarify the causes?
  • CBP staff reported that only about 30 import shipments (out of nearly 21,000 shipments found to be in violation of ISPM#15 requirements) have received a financial penalty. How can USDA and Customs officials justify this failure to enforce the regulations?

 

 

What Can Be Done to Close Down the Wood Packaging Pathway

 

I suggest that our goal should be to hold foreign suppliers responsible for complying with ISPM#15. One approach is to penalize violators. APHIS and Customs might

  • Prohibit imports in packaging made from solid wood (boards, 4 x 4s, etc.) from foreign suppliers which have a record of repeated violations over the 11 years ISPM#15 has been in effect (17 years for exporters from Hong Kong & mainland China). Officials should allow continued imports from those same suppliers as long as they are contained in other types of packaging materials, including plastic, metals, or fiberboards.
  • Fine an importer for each new shipment found to be out of compliance with ISPM#15 in cases when the foreign supplier of that shipment has a record of repeated violations.

 

There would need to be a severe penalty to deter foreign suppliers from simply changing their names or taking other steps to escape being associated with their violation record.

 

At the same time, the agencies should work with non-governmental organizations and importers to promote creation of an industry certification program that would recognize and reward importers who have voluntarily undertaken actions aimed at voluntarily exceeding ISPM#15 requirements so as to provide a higher level of protection against invasive species that would otherwise potentially be introduced into the United States.

 

What You Can Do

  • Tell your member of Congress and Senators that you are worried that our trees are still being put at risk by insects arriving in wood packaging. Ask them to urge the USDA Secretary Sonny Perdue to take the actions outlined above in order to curtail introductions of additional tree-killing pests.
  • Talk to your friends and neighbors about the threat to our trees. Ask them to join you in communicating these concerns to their Congressional representatives and Senators.
  • Write letters to the editors of your local newspaper or TV news station.

 

Use your knowledge about pests threatening trees in your state or locality in your communications!

 

Other Introduction Pathways for Cerambycids

tree removals in Tukwilla, WA to eradicate citrus longhorned beetle; photo by Washington State Department of Agriculture

Plants for planting

Other studies have confirmed that importation of living plants (called by regulators “plants for planting”) is a high-risk pathway for introducing tree-killing pests. See the Eyre and Haack chapter for a summary.

This is as true for highly damaging Cerambycids as for other types of plant pests. One of the most damaging is the citrus longhorned beetle (CLB) (Anoplophora chinensis). CLB [https://www.dontmovefirewood.org/invasive-species/] poses an even greater threat to North American forests than ALB – it has a wider host range and climate-matching models show that it could establish across most of the United States. CLB were detected in a nursery in Tukwilla, Washington, in 2001; the pest was eradicated. Nine CLB outbreaks have been detected in Europe; three are considered eradicated (Eyre & Haack 2017).

Eyre and Haack (2017) report that in Europe of the 455 Cerambycidae intercepted over the period 1998 – 2013, 54 were on imported in living plants. These included probably 49 citrus longhorned beetle (CLB). Most were detected primarily on maple nursery stock that originated China (32), with smaller numbers from other countries, including Netherlands (8), and Italy (where CLB has been established).

New Zealand has intercepted 74 CLB on plants for planting over the 28 year period 1980 – 2008.  One third of this total was intercepted in 2008.

 

Authorities’ Responses (or lack thereof)

Europe

  • Since 2012, the European Union has required that 10% of CLB host plants imported into the European Union should be destructively sampled (that is, dissected to see whether insects are present internally).
  • This requirement supplements a broader requirement that plants for planting be treated as a high risk commodity. Member states are required to inspect all incoming P4P consignments. This requirement is, however, undermined by much more lenient requirements regarding movement of plants among EU member states – some genera are not regulated … others are controlled by Plant Passports – an industry-led scheme.  [For more on this issue, see my blog from October 2016 here.

 

United States

  • APHIS issued a Federal order tightly restricting imports of CLB hosts from Europe in 2013 – four years after a CLB outbreak was detected in a part of the Netherlands which is a center for the production of hardy ornamental nursery stock for European and probably American markets.
  • APHIS proposed to revise its overall plant importation regulations (the “Q-37 regulations) to rely more on integrated management by the exporting nurseries in contrast to port inspections. This rulemaking has stalled. [See my blog about this here.]

 

Finished Wood Products

While no country is keeping comprehensive records, finished wood products have transported longhorned beetles.  Eyre and Haack (2017) concluded that upholstered furniture presents one of the highest risk among the finished wood products – partly because imports are rising rapidly, partly because insect-damaged wood can be hidden under the upholstery. New Zealand found that some Asian manufacturers place good quality wood on visible surfaces and poor quality timber (insect damaged and bark covered) in internal sections. Officials inspected 49 couches and found that 30 had wood with bark, 19 had insect contaminants, and 32 had visible insect damage. Fungal samples were isolated from 11 of the couches. They found 4 longhorned beetles.

 

References

Wang, Q. (Ed.). 2017. Cerambycidae of the world: biology and pest management.  Boca Raton, FL: CRC Press

The chapter on biosecurity is available here:  http://treesearch.fs.fed.us/pubs/54552

A chapter on Cerambycid impacts in urban and rural forests is available here: http://treesearch.fs.fed.us/pubs/54543

 

We welcome comments that supplement or correct factual information, suggest new approaches, or promote thoughtful consideration. We post comments that disagree with us — but not those we judge to be not civil or inflammatory.

 

Posted by Faith Campbell

California – volunteers make major efforts

polyphagous shot hole borer exit holes on box elder; photo source http://ucanr.edu/

I have posted many blogs criticizing California state authorities for not acting to counter several highly damaging tree-killing pests, such as the goldspotted oak borer and invasive shot hole borers.

I should have made it clear that many Californians – academics, employees of local, state, and federal agencies, concerned citizens – are working very hard to develop scientific knowledge, test strategies, educate stakeholders and those whose activities facilitate the insects’ spread. These people have carried forward a wide range of dedicated efforts that do much to make up for the lack of state or federal agencies’ engagement.

More than 60 stakeholder entities now participate in one or more of nine working groups focused on shot hole borers, promoting research, education and outreach. Some of these activities receive advice (but apparently no funding) from California Department of Food and Agriculture. Outreach to the media has resulted in some good coverage. Master Gardeners and other potential citizen scientist groups have been trained. See here.

A smaller but older group is carrying out similar activities targetting goldspotted oak borer; visit here.

 

Here I summarize some of the most recent activities.

1) Scientists have released a pocket-sized guide for identifying trees infested by polyphagous or Kuroshio shot hole borers (For summaries of the threat posed by these insects and their associated fungi, visit here). The guide can be downloaded here.

The Guide is useful for people outside as well as inside California, since some host species grow across the continent: box elder (Acer negundo), sweetgum (Liquidambar styraciflua), tree of heaven (Ailanthus altissima), mimosa or silk tree (Albizia julibrissin).

Other hosts are common in horticulture: camellia (Camellia semiserrata), Japanese maple (Acer palmatum), Japanese wisteria (Wisteria floribunda), London plane (Platanus x acerifolia), mimosa, and weeping willow (Salix babylonica).

The shot hole borers could be present outside the six California counties known to contain infestations because one or both of these beetles could have been spread via movement of wood, greenwaste, or nursery stock; or they could have entered other parts of the country on plants or wood from Asia.

 

2) Scientists are testing possible pesticide treatments to protect trees from polyphagous shot hole borer

The polyphagous shot hole borer (a still undescribed beetle in the Euwallacea genus), attacks more than 200 host tree species in southern California, including many important native and urban landscape trees. Forty-nine species from more than 20 families are known to be reproductive hosts. Trees are dying in parks, residential neighborhoods, other public landscapes, and riparian areas.  John Boland of Southwest Wetlands Interpretive Association has documented that 88% of the willows in the Tijuana River Valley have been infested by the Kuroshio shot hole borer – although many of the trees regrow into four-foot-tall shrubs. Dr. Boland estimates that more than two billion KSHB hatched in the valley during 2015-2016.

Confronted by such threats, home owners, park managers, and arborists are desperate for management tools.

As reported by Jones et al. 2017 (see reference below), scientists tested the effectiveness of insecticides, fungicides, and insecticide–fungicide combinations for controlling continued PSHB attacks on previously infested California sycamore trees. The combination of a systemic insecticide (emamectin benzoate), a contact insecticide (bifenthrin), and a fungicide (metconazole) provided the best control over the six months of the study period. The biological fungicide Bacillus subtilis provided short-term control.

Efficacy of the treatment combination is not yet settled. First, the polyphagous shot hole borer actively oviposits year-round, and both adults and larvae may be found in an infested tree at any time of year. Furthermore, the shot hole borers are active throughout the sapwood, not just in the phloem and cambium tissues. These differences in behavior may make timing and efficacy of systemic insecticides more difficult to predict. In addition, it is extremely difficult to detect infestations at an early stage, when treatment is most likely to be effective. Finally, the treated trees should be monitored over several years, rather than for six months, to evaluate true efficacy.

 

3) Efforts to gain official actions re: Invasive Shot Hole Borers

Some people are trying to promote state engagement. They are focused on getting adoption of a strategy under the auspices of the California Invasive Species Council to create a system to respond to bioinvaders that don’t fall within the California Department of Food and Agriculture’s definition of its responsibilities – e.g., the shot hole borers. The invasive shot hole borers are included in the interagency “Charting the Pest Prevention System in California” plan.

 

4)  On-the-Ground Efforts

Some entities are compiling and publicizing their costs for responding to the several wood borers. For example, the University of California Irvine reports spending close to $2 million to manage trees on campus that have been attacked. The Orange County parks agency has spent $1.7 million on shot hole borer surveys, tree inventory, public outreach materials, staff training, and some research. These costs are rising – in the first half of 2017, Orange County parks agency has already spent $348,000 on tree treatment and removal.

UC Cooperative Extension for San Diego County organized a Green Waste-Wood Biomass Symposium in February aimed at educating industry and public agency waste-management practitioner.

Goldspotted Oak Borer

Three National forests are treating high-value oaks in specific sites:

  1. Cleveland NF sprayed 248 oak trees with the contact insecticide, carbaryl. The Forest hopes to continue the treatments yearly dependent on funding and need.
  2. The Angeles NF removed 50 GSOB-infected oaks in Green Valley. They then tagged about 1,000 oak trees in the area so their changing conditions can be monitored.
  3. San Bernardino NF is felling and debarking GSOB-infested oaks on the periphery of the communities of Idyllwild and Pine Cove.

Orange County removed highly infested trees at Weir Canyon; now spraying another 1,672 oaks, including both lightly infested and neighboring trees, with carbaryl  … monitoring has not detected any other infested trees in Weir Canyon or neighboring Blind Canyon.

 

Summarized from the San Diego County update (reference below).

In the absence of legal mechanisms to stop the movement of infested firewood, collaborating organizations have focused on public education and outreach programs for the firewood industry, tree care professionals, and the public. Still, some infested wood continues to be moved – probably to uninfested areas.

The Update also reports the following impacts of the goldspotted oak borer in San Diego County:

  • Eight San Diego County Parks have suffered loss of habitat, diminished recreational value, and direct costs associated with tree removal and grinding and insecticidal treatments. More than 5,000 trees have been lost in just one park, William Heise Park.
  • One California State Park lost nearly $500,000 in campground and day-use fees when areas were closed for tree removal. GSOB has been discovered at two more State parks in recent years.
  • The Cleveland National Forest has suffered negative environmental, economic and aesthetic impacts; removed more than 200 trees and treated 248 high-value trees on developed sites.
  • Tribal lands have lost oaks of great cultural value as well as reduced habitat, shade, and recreational enjoyment.
  • Urban and rural residential homeowners are faced with removal and disposal costs averaging $1,500 per tree.
  • Fire, transportation, and public works agencies are dealing with higher fuel loads and hazard trees along rights of way.

 

GSOB activists are collaborating with those working on the invasive shot hole borers to seek state and federal support.

 

SOD-infected tanoak; photo by F.T. Campbell

UPDATE ON SUDDEN OAK DEATH

Eight California nurseries were found late this spring to be infected by the sudden oak death pathogen (Phytophthora ramorum).  (As of May, only two nurseries were known to be positive.) Seven of the positive nurseries are located in counties with disease in the natural environment. Given the wet winter and spring in California, this upswing is probably not surprising. Still, this sudden upsurge raises questions about the efficacy of nursery regulations. One of the nurseries was detected as a result of a trace-back investigation – not through the annual inspection.

SOURCES

California Oak Mortality Task Force newsletter, July 2017

Goldspotted Oak Borer and Oak Mortality Quarterly Situation Report April 1 through June 30, 2017

Status of Goldspotted Oak Borer – July 2017 Update Goldspotted Oak Borer Steering Committee www.GSOB.org Email: gsobinfo@ucdavis.edu

 Invasive Shot Hole Borer (Polyphagous and Kuroshio)/Fusarium Dieback Quarterly Situation Report January 1 through March 31, 2017

Jones, M.E., J. Kabashima, A. Eskalen, M. Dimson, J.S. Mayorquin, J.D. Carrillo, C.C. Hanlon, and T.D. Paine. 2017. Evaluations of Insecticides and Fungicides for Reducing Attack Rates of a new invasive ambrosia beetle (Euwallacea Sp., Coleoptera: Curculionidae: Scolytinae) in Infested Landscape Trees in Calif. Journal of Economic Entomology, 110(4), 2017, 1611–1618 doi: 10.1093/jee/tox163 Advance Access Publication Date: 5 July 2017

 

We welcome comments that supplement or correct factual information, suggest new approaches, or promote thoughtful consideration. We post comments that disagree with us — but not those we judge to be not civil or inflammatory.

Posted by Faith Campbell

Invasive “hot spot” study confirms vulnerable places, causes of introductions

removing Miconia from Hawaiian forest; courtesy of the Nature Conservancy of Hawai`i

A recent article by Wayne Dawson and 24 coauthors (see reference at the end of this blog) provides the first-ever global analysis of established alien species. They studied the diversity of established alien species belonging go eight taxonomic groups – amphibians, ants, birds, freshwater fish, mammals, reptiles, spiders and vascular plants – across 609 regions (186 islands or archipelagos, and 423 mainland regions).

The analysis found that the highest numbers of established alien species in these taxonomic groups were in the Hawaiian Islands, New Zealand’s North Island and the Lesser Sunda Islands of Indonesia. The Hawaiian Islands have high numbers of invasive species in all of the eight groups studied. In New Zealand, the highest numbers were invasive plants and introduced mammals that prey on the native birds.

Florida is the top hotspot among mainland regions. Florida is followed by the California coast and northern Australia.

Burmese python in the Florida Everglades; photo by U.S. Fish & Wildlife Service

Patterns

 Invasive species hotspots were found mainly on islands and in coastal regions of mainland areas. The lead author, Dr. Wayne Dawson, a researcher at Durham University’s Department of Biosciences, suggested that the greater invasive species richness in coastal regions probably results from higher rates of species introductions to port areas compared to interior regions.

Island regions have, on average, higher cross-taxon invasive species richness. This cross-taxon richness on islands tends to be higher for those islands further from continental landmasses. The authors suggest that such oceanic islands might be more likely to import large quantities of goods from foreign sources than islands close to continents, thus experiencing higher propagule pressure.

 

Associations

Regions with greater wealth (measured as per capita GNP), human population density, and area have higher established alien richness. These effects were strongest on islands. The authors suggest that wealth and human population density might correlate with higher numbers of species being brought to the region through trade and transport.

On mainlands, cooler regions have higher richness. I think this might reflect history – centuries of colonial powers importing plants and animals. However, colonial powers also introduced species to tropical regions.  In contrast, on islands warmer and wetter regions have higher richness of invasive species.

 

Drivers

The authors conclude that cumulative numbers of invasive species at a particular location are driven to a greater extent by differences in area and propagule pressure than by climate. The model that best explains cross-taxon invasive species richness combines per capita GDP, population density and sampling effort. Other important factors are area of the region, mean annual precipitation, and whether a region is on a mainland or island(s).

The study results show that, per unit increase in area, per capita GDP, and population density, invasive species richness increases at a faster rate on islands than on mainlands. This might be confirmation of the longstanding belief that islands are more readily invaded than mainlands, although the authors caution that a rigorous test of this explanation would require data on failed introductions.

The authors call for additional research to understand whether these effects arise because more species are introduced to hotspot regions, or because human disturbance in these regions makes it easier for the newcomers to find vacant spaces and opportunities to thrive.

 

I think it would be helpful to compare the findings on invasive species richness in specific regions to data on historic patterns of trade and colonization to strengthen our understanding of the importance of propagule pressure in determining invasion patterns.

 

Increasing Confirmation of Significance and Breadth of Invasive Species Threat

The Dawson et al. study is the latest in a series of analyses of global or regional patterns in invasive species. I have blogged previously about several of these:

  • Bradshaw et al. 2016 concluded that invasive insects alone cause at least $77 billion in damage every year, a figure they described as a “gross underestimate”.
  • A study by Hanno Seebens and 44 coauthors showed that the rate of new introductions of alien species has risen rapidly since about 1800 – and shows no sign of slowing down. Adoption of national and international biosecurity measures have been only partially effective, failing to slow deliberate introductions of vascular plant species, birds, and reptiles, and accidentally introduced invertebrates and pathogens. Like Dawson et al, Seebens et al. found a strong correlation between the spread of bioinvaders introduced primarily accidentally as stowaways on transport vectors or contaminants of commodities (e.g., algae, insects, crustaceans, molluscs and other invertebrates) and the market value of goods imported into the region of interest.
  • Liebhold et al. 2016(see reference below) studied insect assemblages in 20 regions around the world. They found that an insect taxon’s ability to take advantage of particular invasion pathways better explained the insect’s invasion history than the insects’ life-history traits. (The latter affect the insect’s ability to establish in a new ecosystem.)
  • Maartje J. Klapwijk and several colleagues note that growing trade in living plants and wood products has brought a rise in non-native tree pests becoming established in Europe. The number of alien invertebrate species has increased two-fold since 1950; the number of fungal species has increased four-fold since 1900.
  • Jung et al. (2015) studied the presence of Phytophthora pathogens in nurseries in Europe. They found 59 putatively alien Phytophthora taxa in the nurseries. Two-thirds were unknown to science before 1990. None had been intercepted at European ports of entry when they were introduced. Nor have strict quarantine regulations halted spread of the quarantine organism ramorum.
  • A report by The World Conservation Union (IUCN) on World Heritage sites globally found that invasive species were second to poaching as a threat to the sites’ natural values. Of 229 natural World Heritage sites examined, 104 were affected by invasive species. Island sites – especially in the tropics – were most heavily impacted.
  • Another report by IUCN found that invasive species were the second most common cause of species extinctions – especially for vertebrates.

Conclusions

These studies demonstrate that

  • Invasive species have become a significant threat to biological diversity and ecosystem services around the world – one that continues to grow.
  • The recent spate of studies originating in Europe probably reflects recent recognition of the continent’s vulnerability – as seen, inter alia, in the proliferation of tree-killing Phytophthoras.
  • Human movement of species – propagule pressure – whether deliberately or due to inadequate efforts to manage trade-related pathways – explain the bulk of “successful” introductions.
  • Economic activity drives introductions, so areas at highest immediate risk are urban areas and other centers receiving high volumes of imports and visitors. Among troubling trends in the future is rapid global urbanization – along with rising economic interdependency.
  • Efforts to curb these movements – at the national, regional, and international levels – have failed so far to counter the threat posed by invasive species of nearly all taxonomic groups.

In my view, the requirements that phytosanitary measures “balance” pest prevention against trade facilitation results in half measures being applied – and half measures achieve halfway results. For example, the U.S. does not require that packaging be made from materials that cannot transport tree-killing pests. The USDA has moved far too slowly to limit imports of plant taxa that pose a risk of either being invasive themselves or of transporting pests known to be damaging.

 

Conservationists should focus on building political pressure to strengthen regulations and other programs intended to curtail this movement. No other approach will succeed.

 

Sources

Bradshaw, C.J.A. et al. Massive yet grossly underestimated global costs of invasive insects. Nat. Commun. 7, 12986 doi: 10.1038/ncomms12986 (2016). (Open access)

Dawson, W., D. Moser, M. van Kleunen, H. Kreft, J. Perg, P. Pyšek, P. Weigelt, M. Winter, B. Lenzner, T.M. Blackburn, E.E. Dyer, P. Cassey, S.L. Scrivens, E.P. Economo, B. Guénard, C. Capinha, H. Seebens, P. García-Díaz, W. Nentwig, E. García-Berthou, C. Casal, N.E. Mandrak, P. Fuller, C. Meyer and F. Ess. 2017. Global hotspots and correlates of IAS richness across taxon groups. Nature Ecology and Evolution Vol. 1, Article 0186. DOI: 10.1038/s41559-017-0186 | www.nature.com/natecolevol

 

Jung,T., L. Orlikowski, B. Henricot, P. Abad-Campos, A.G. Aday, O. Aguin Casa, J. Bakonyi, S.O. Cacciola, T. Cech, D. Chavarriaga, T. Corcobado, A. Cravador, T. Decourcelle, G. Denton, S. Diamandis, H.T. Doggmus-Lehtijarvi, A. Franceschini, B. Ginetti, M. Glavendekic, J. Hantula, G. Hartmann, M. Herrero, D. Ivic, M. Horta Jung, A. Lilja, N. Keca, V. Kramarets, A. Lyubenova, H. Machado, G. Magnano di San Lio, P.J. Mansilla Vazquez, B. Marais, I. Matsiakh, I. Milenkovic, S. Moricca, Z.A. Nagy, J. Nechwatal, C. Olsson, T. Oszako, A. Pane, E.J. Paplomatas, C. Pintos Varela, S. Prospero, C. Rial Martinez, D. Rigling, C. Robin, A. Rytkonen, M.E. Sanchez, B. Scanu, A. Schlenzig, J. Schumacher, S. Slavov, A. Solla, E. Sousa, J. Stenlid, V. Talgø, Z. Tomic, P. Tsopelas, A. Vannini, A.M. Vettraino, M. Wenneker, S. Woodward and A. Perez-Sierra. 2015. Widespread Phytophthora infestations in European nurseries put forest, semi-natural and horticultural ecosystems at high risk of Phytophthora disease. Forest Pathology.

 

Klapwijk, M.J., A.J.M. Hopkins, L. Eriksson, M. Pettersson, M. Schroeder, A. Lindelo¨w, J. Ro¨nnberg, E.C.H. Keskitalo, M. Kenis. 2016. Reducing the risk of invasive forest pests and pathogens: Combining legislation, targeted management and public awareness. Ambio 2016, 45(Suppl. 2):S223–S234  DOI 10.1007/s13280-015-0748-3  [http://www.nature.com/articles/ncomms14435 ]

 

Liebhold, A.M., T. Yamanaka, A. Roques, S. Augustin, S.L. Chown, E.G. Brockerhoff, P. Pysek. 2016. Global compositional variation among native and nonindigenous regional insect assemblages emphasizes the importance of pathways. Biological Invasions (2016) 18:893–905

 

Seebens, H. et al., 2017. No saturation in the accumulation of alien species worldwide. Nature Communications. January 2017. [http://www.nature.com/articles/ncomms14435 ]

 

 

We welcome comments that supplement or correct factual information, suggest new approaches, or promote thoughtful consideration. We post comments that disagree with us — but not those we judge to be not civil or inflammatory.

 

Posted by Faith Campbell

 

 

How we can strengthen programs to protect trees from invasive pests

USDA; photo by F.T. Campbell

Every five years, Congress adopts a new Farm Bill. The House and Senate Agriculture committees are  holding hearings and considering proposals for the Farm Bill due to be adopted in 2019. Now is the time for people concerned about the continuing introductions of forest pests and weakness of our government’s response to pests that have become established to ask their Representative and Senators to adopt legislative language to strengthen relevant USDA programs. I suggest specific proposals below – which I hope you will urge your representatives to support.

The Farm Bill supports our Nation’s largest soil and water conservation programs. The Farm Bill can also be used to create new programs that address other issues – such as pest prevention and response.

The Farm Bill already has been used to strengthen APHIS’ phytosanitary programs. For example, Section 10007 of the 2014 Farm Bill provides more than $50 million annually for the Plant Pest and Disease Management and Disaster Prevention Program. These funds have supported numerous vitally important research and management programs targetting polyphagous shot hole borer, spotted lanternfly, velvet longhorned borer, thousand cankers disease, emerald ash borer, as well as more general goals such as improving traps for detecting wood-borers and outreach about emerald ash borer to Native American tribes. With APHIS’ annual appropriations falling far short of the resources needed to respond to invasions by numerous plant pests, Section 10007 has provided essential supplements to the agency’s programs.

The new Farm Bill to be adopted by the Congress offers opportunities to strengthen other components of USDA programs with the goal of protecting the tree species comprising our wildland, rural, and urban forests.

The Center for Invasive Species Prevention and Vermont Woodland Owners Association have developed several proposals that we hope will be incorporated into the 2019 Farm Bill. These proposals have been endorsed by the Reduce Risk from Invasive Species Coalition.  The amendments have also been endorsed by the Weed Science Society of America. CISP submitted testimony summarizing these proposals to the Senate Committee on Agriculture, Nutrition, and Forestry in early July, when the Committee held a hearing on the Farm Bill’s conservation and forestry programs. (For a copy of our testimony, contact us using the “contact us” button.)

You can help by contacting your Representative and Senators and asking them to support these proposed amendments to the 2019 Farm Bill.

These proposed amendments seek to address the following needs.

  • Do you wish to strengthen APHIS’ commitment to pest prevention in the face of a competing mandate to facilitate trade?

Then you might want to support a proposed amendment to Section 3 of the Plant Protection Act. The new language would read as follows:

“(3) It is the responsibility of the Secretary to facilitate exports, imports and interstate commerce in agricultural products and other commodities that pose a risk of harboring plant pests or noxious weeds in ways that will reduce prevent, to the greatest extent practicable feasible, as determined by the Secretary, the risk of dissemination of plant pests and noxious weeds.”

  • Do you wish to increase funding for APHIS’ programs responding to recently-detected plant pests?

Then you might want to support a proposed amendment that would expand APHIS’ access to emergency funds by enacting a broad definition of “emergency”. Under the new definition, “emergency” would mean “any outbreak of a plant pest or noxious weed which directly or indirectly threatens any segment of the agricultural production of the United States and for which the then available appropriated funds are determined by the Secretary to be insufficient to timely achieve the arrest, control, eradication, or prevention of the spread of such plant pest or noxious weed.”

This amendment would help APHIS evade the downward push of its declining annual appropriation and enable the agency to tackle more of the tree-killing pest that have entered the U.S.

Customs inspecting wood packaging

  • Do you wish to promote stronger measures aimed at minimizing the presence of pests in wood packaging material? (I have blogged repeatedly about the continuing pest risk associated with the wood packaging pathway.)

Then you might want to support a proposed amendment that would establish a non-governmental Center for Agriculture-Trade Partnership Against Invasive Species. That Center would promote industry best practices, encourage information-sharing, and create an industry certification program under which importers would voluntarily implement pest-prevention actions that are more stringent than current regulations (ISPM#15) Link require.

American Chestnut Foundation chestnut in experimental planting in Fairfax County, Virginia; photo F.T. Campbell

  • Do you wish to strengthen efforts to develop programs that would provide long-term funding to support 1) research and development of long-term pest-control strategies such as biological control and breeding of trees resistant to insects or pathogens and 2) testing, development, and implementation of strategies to restore to the forest native tree species that have been severely depleted by non-native pests?

Then you might want to support a pair of proposed amendments that would:

  1. Establish a fund, to be managed by the National Institute of Food and Agriculture, to provide grants under which eligible institutions would carry out research intended to test and develop strategies aimed at restoring such tree species. Such strategies might include finding, testing, and deploying biological control agents or breeding of trees resistant to pests.
  2. Amend the McIntyre-Stennis Act to establish a fund to provide grants to support programs to eligible institutions to conduct experimental plantings aimed at restoring such tree species to the forest.

You can obtain copies of the proposed amendments, in legislative language, by contacting us using the “contact us” button.

Your efforts will be valuable in any case … but if your Representative or Senator is on the agriculture committee, contacting that Member will be most important!

Members of the Senate Committee on Agriculture, Nutrition, and Forestry:

Republicans (majority):

  • Pat Roberts, KS, Chairman
  • Thad Cochran, MS
  • Mitch McConnell, KY
  • John Boozman, AR
  • John Hoeven, ND
  • Joni Ernst, IA.
  • Chuck Grassley, IA
  • John Thune, SD.
  • Steve Daines, MT
  • David Perdue, GA
  • Luther Strange, AL

Democrats (minority):

Members of the House Committee on Agriculture

Republicans (majority):

Democrats (minority):

 

We welcome comments that supplement or correct factual information, suggest new approaches, or promote thoughtful consideration. We post comments that disagree with us — but not those we judge to be not civil or inflammatory.

Posted by Faith Campbell