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 “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


 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.



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.



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.


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.



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 |


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  [ ]


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. [ ]



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



Bill aimed at controlling invasive species on the ground advances

whitebark pine in Crater Lake National Park killed by white pine blister rust; photo by F.T. Campbell

In the first days of April, the Senate Environment and Public Works Committee  adopted the Wildlife Innovation and Longevity Driver Act (S. 826) (the WILD Act).

Title II of this legislation would amend the Fish and Wildlife Coordination Act by inserting language very similar to the Federal Land Invasive Species Control, Prevention, and Management Act (S. 509).  I blogged last year about that  bill and a hearing about it here.

Our concerns at the time focused on:

  • The provision allowing invasive control projects to proceed without first being evaluated by an environmental impact statement or environmental assessment. Lack of careful analysis could expose the environment to additional damage. For example, use of herbicides or grazing to control invasive plants can lead to suppression of native forbs. Suppressing invasion by one set of plants – whatever the strategy used – often facilitates a secondary invasion.
  • The mandatory funding allocations – which severely limit funds available to support research, outreach, and strategic planning and coordination – could undercut activities crucial to development and implementation of effective strategies and management tools.
  • The mandatory goal of reducing invasive species populations by 5% per year is unrealistic.
  • New requirements on reporting and coordination might divert already-thin resources and delay needed action.
  • Priority-setting. Managing invasive species on national lands should reflect national goals and perspectives, not be set by states’ governors.

Caroline Murphy of The Wildlife Society and I have reviewed Title II of the new WILD Act and find that it differs from last year’s invasive species control bill in several important ways:

  • The bill now applies to a wider range of agencies. The Secretary of the Army (who supervises the Corps of Engineers) is included explicitly; he joins the secretaries of Interior and Agriculture (as supervisor of the Forest Service). In addition, the bill also applies to the head of “any federal agency” having duties related to planning or treatment of invasive species “for the purpose of protecting water and wildlife on land and in water.”
  • Most important, projects are no longer granted a “Categorical Exclusion” from preparing environmental impact analyses. Instead, under an “Expedited Action” provision, the Secretaries are instructed to use all existing legal tools and flexibilities to expedite projects and activities.
  • The bill still requires that 75% of invasive species funds be allocated to “on-the-ground control and management of invasive species.” But such activity now may include “the use of appropriate methods to remove invasive species from a vehicle or vessel capable of conveyance.” I wish the language also included efforts to prevent invasive species from being present in or on the vehicle or vessel.
  • The bill has dropped the requirement that invasive species’ populations be reduced by 5% annually. The bill now requires the Secretaries to develop a strategic plan “to achieve, to the maximum extent practicable, a substantive annual net reduction of invasive species populations or infested acreage on land or water” that the Secretary manages. It is still not clear whether that reduction should apply to some or all of the invasive species there.

I am still concerned that

  • Projects are to use least-cost methods. This requirement is likely to favor reliance on chemical controls, which could have significant non-target impacts and might not provide lasting control. This incentive might be counter-balanced by the requirement that the methods be effective, based on sound scientific data. However, the bill’s focus on measuring annual results rather than long-term efficacy will add to pressures to rely on short-term approaches that could undermine long-term effectiveness.
  • Leadership of the projects – especially setting priorities – will be in hands of state governments, not the federal agencies which have the responsibility under federal law to manage the lands and waters that are to be protected. A partial counter-balance is the requirement that the appropriate federal agency Secretary determine which lands or waters need immediate action to address the invasive species risk.  Furthermore, the expedited actions are to be carried out in accordance with agency procedures, including any applicable land or resource management plan

I welcome the requirement that the Secretaries, in developing their strategic plans, must take into consideration the ecological as well as the economic costs of acting or not acting.

As before, the projects are to be carried out through collaboration with wide range of partners, including private individuals and entities – apparently including non-governmental organizations such as state or local invasive plant coalitions.

The rest of the WILD Act would reauthorize the Partners for Fish and Wildlife Program, some Multinational Species Conservation Fund Programs, and create several conservation-related competitive grant programs to be managed by the National Fish and Wildlife Foundation, one of which is for the management of invasive species.

Now that these provisions are incorporated into a wider bill, and Senator Barasso is chairman of the full committee, adoption of some version of this legislation now seems more likely than I thought last year.  Apparently there is still no action in House on the parallel bill.

While I am heartened by some of the changes in the bill since last year, I continue to think that America’s public lands would be better protected by a more comprehensive approach that includes prevention, mapping, early detection, research, prioritization, coordination and outreach aimed at engaging key stakeholders.  Such an approach was outlined in a document developed a couple of years ago by the National Environmental Coalition on Invasive Species (NECIS) – available here.

Posted by Faith Campbell

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.

New Secretary of Interior Pledges to Support Invasive Species Efforts — Let’s Ask USDA Secretary to do the Same!

Interior Secretary nominee Ryan Zinke

During his confirmation hearing Ryan Zinke, nominated to be the new Secretary of Interior, committed to several senators that he would explore ways to better manage invasive species on federal lands – especially in National parks – and to strengthen the National Invasive Species Council (NISC).

Mr. Zinke is currently a Congressional Representative from Montana. Senator Debbie Stabenow (MI) pressed him on invasive species issues during the hearing, focusing on the threat to the Great Lakes of carp and other aquatic species. Also, Senators Al Franken (MN), Joe Manchin (WV), and Mazie K. Hirono (HI) asked about invasive species in written questions submitted to the nominee.

Mr. Zinke answered most questions the same way:  He shares the Senator’s concern, especially since  Montana has significant invasive species problems. Also, he thinks it is critical that federal land managers be encouraged and empowered to be good neighbors in controlling invasive species in cooperation with adjacent private land owners. …  Specifically he wants to explore ways to implement the Early Detection Rapid Response Framework adopted by NISC in 2016.


* Sen. Franken included a single question on bioinvaders among a long list of questions on other topics. He mentioned the emerald ash borer as one example of a damaging invader in Minnesota. Senator Franken asked Mr. Zinke:

1) what steps he would take to enhance invasive species control on public lands

See paragraph above for Mr. Zinke’s answer.

2) whether he would enforce the Lacey Act and explore ways to strengthen it.

Mr. Zinke said he would enforce the law. He is aware that there is broad bipartisan frustration with the lack of an efficient process for listing injurious species under the Act. He would ask the Fish and Wildlife Service to recommend ways to improve its implementation. If legislative changes might be helpful, he would be pleased to have that conversation with the Congress.


* Sen. Manchin’s first question (!) asked how Mr. Zinke might strengthen NISC to help manage invaders across multiple types of land ownership. See Mr. Zinke’s frequent reference to his Montana experience above for his answer.


* Sen. Hirono asked five questions pertaining to invasive species! Her first question concerned steps to protect National parks (especially in Hawaii) from bioinvasion. Here, Mr. Zinke gave his usual response but added: “I am especially concerned that Hawaii’s unique flora and fauna are vulnerable to invasive species. I would not want to see invasive species push any of these unique plants and animals onto the Endangered Species list. Once confirmed, I will ask the National Park Service to present me with options for better protecting our national parks from invasive species.”


Ms. Hirono also asked about strengthening NISC. Mr. Zinke responded as follows: “…, I will explore ways to improve the operations of the National Invasive Species Council, and actively engage with the Secretaries of Commerce and Agriculture to get off to a strong start on this issue. … We also need to create a more effective linkage between the National Invasive Species Council policy operation in Washington, DC, and the on the ground federal land managers across the country who deal with invasive species on a daily basis…”


Also, Sen. Hirono asked for Mr. Zinke to help Hawai`i and other U.S. Pacific islands to counter the spread of invasive species through movement of military equipment. Mr. Zinke said he would work to enhance coordination with the Department of Defense and the Pacific island communities to reduce the risks posed by invasive species. … explore how we may implement the recent framework for early detection and rapid response …


Mr. Zinke also promised to work with Senator Hirono on several issues under Interior jurisdiction that are priorities for Hawai`i, among them invasive species.



What We Should Ask the new President & Congress to Do re: Invasive Species

While there are many opportunities for the Congress to strengthen U.S. invasive species programs (see my blog from December 31 here, the most important activity NOW is the confirmation of Sonny Perdue as Secretary of Agriculture. Contact your Senators and urge them to ask Governor Perdue how he will address invasive species challenges.

USDA Secretary nominee Sonny Perdue

Possible questions:

Q: How serious do you think is the threat to American natural resources from invasive (non-native) insects, pathogens, and plants? Can you suggest steps you would take to strengthen the efforts of the Animal and Plant Health Inspection Service (APHIS) aimed at controlling introduction and spread of such bioinvaders into the United States?

Q: The principal legal authority for preventing introductions of invasive plants and plant pests is the Plant Protection Act. The PPA provides strong authority but its implementation has been hampered by internal USDA decisions. How would you ensure that the Department corrects these problems and actively enforces its regulations aimed at ensuring the health and productivity of America’s plant resources?

  • In recent years, more than 20 previously undetected plant pests have been detected in the country each year. Hundreds of shipments of goods entering the country each year contain plant pests. What strategies would you promote to reduce the introduction, spread, and impacts of invasive species?

Q: Given the ever-tightening budget allocated to agencies responsible for addressing invasive species threats, what steps would you take to ensure that our country does not suffer waves of new invasions?

If you have a working relationship with your Senators and believe they understand the invasive species issue fairly well, you might want to suggest more detailed questions:

Q: As you know, the Animal and Plant Health Inspection Service (APHIS) is responsible for preventing introduction and spread of plant pests.

  • In some cases, APHIS has been hesitant to use its authority to penalize importers which routinely receive shipments that violate plant pest (phytosanitary) regulations. [You might cite my blog from last week  which illustrates examples pertaining to wood packaging.] Will you instruct APHIS to use its legal authority to impose civil penalties to deter continuing violations?


  • Trying to prevent pest introductions by increasing the percentage of shipments that are inspected visually will not be effective in many cases. This is true especially with regard to one of the most important pathways by which plant pests are introduced – imports of living plant material such as nursery stock. APHIS began updating its regulations governing plant imports nearly four years ago, but the proposed new regulations have been not been finalized. Will you look into the reasons for delay and take steps to update these regulations to focus on pathway cleanliness rather than continue to rely on ineffective visual inspections?

Q: Urban forests across the country are under threat from a growing number of non-native or introduced insect pests. Examples include the emerald ash borer – now found in 27 states; Asian longhorned beetle – which threatens a large proportion of urban trees across the country; and polyphagous and Kuroshio shot hole borers – killing many trees in southern California.

Urban forests are at particularly high risk of infestation by non-native pests because they are growing near ports and other transportation hubs where such pests are first introduced. Furthermore, each individual tree in an urban setting provides important benefits in the form of shade, moderation of storm water runoff, abatement of air pollutants, enhanced property values, and neighborhood amenities.

  • Will you fully utilize the authorities under the Plant Protection Act to help ensure the health and productivity of America’s urban forests?
  • [If you have not already suggested the questions outlined above re: wood packaging and other pathways, you might suggest them in this context.]


The Secretary of Agriculture also oversees the Forest Service. Pertinent questions:

Q: Invasives are as great a threat to eastern forests as wildfires are in the West. Despite the growing damage and ecological destruction we are witnessing the budgets for research on strategies to minimize these bioinvaders’ impacts are actually falling. How will you work to provide solutions to this quandary?

As I said in my blog at the end of December, what is missing is a political demand for action – and support for necessary staff and funding. Agencies under the secretaries of Agriculture and Interior bear most of the responsibility for managing invasive species. As long as these officials are not being pressed by key Congressional committees, the media, and key stakeholders to take more aggressive and effective action to curtail species introductions and suppress established populations of bioinvaders, they will continue to focus their attention on issues that do generate these kinds of political pressure.

Posted by Faith Campbell

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.


Firewood: Important Progress — and a Troubling Stalemate


After years of work, the combined efforts of many staff at federal agencies and non-profits have succeeded in placing a firewood alert message on the website for all of the 3,163 federal  campgrounds managed by the National Park Service, USDA Forest Service, and Corps of Engineers for which visitors can reserve a spot in advance. Only 43 federal reserveable campgrounds remain without messaging. These are managed by the Bureau of Land Management, Bureau of Reclamation, and the US Fish and Wildlife Service.

As of October 2016, visitors reserving campgrounds through the services of Reserve America or for any National parks, National forests, or Army Corps reservoirs will find new information in the “Know before you go” section – a message about not moving firewood.

The messages vary somewhat  by agency, but basically say:  “Don’t move firewood!”  They often add “buy firewood at or near your destination and burn it on-site.”  Some messages include a brief explanation about the aim — to prevent or limit spread of invasive tree-killing pests. Some include a message that some states regulate firewood movement. There is a link to either the national program — – or to the pertinent state program, e.g., the California Firewood Task Force for National Forest campgrounds in Region 5.

Some federal campgrounds do not use the system and therefore require separate efforts to improve firewood messaging. This includes several popular water-based recreation sites in the central southern states, such as the Arkansas River National Recreation Area and Oachita National Forest. Many states in this region also do not regulate firewood. [See my earlier blog contrasting management of firewood with management of boats and attached  mussels or aquatic plants here and the article by Frank Koch and colleagues, referenced below.]

Those who succeeded in achieving the widespread adoption of this outreach program deserve our thanks and praise! They worked long and hard for this.


On a Less Positive Note…

Unfortunately, efforts to put a firewood certification program into place appear to have stalled.

In March 2010, in response to increasing concern across the country, APHIS issued a first-ever firewood strategy, with a number of important elements.  It proposed the following:

Outreach Strategies:

  1. State and Federal agencies should convene a communications steering committee.
  2. Develop an online hub of firewood outreach materials.
  3. Prioritize the outreach activities.
  4. Use diverse methods to get consistent messages out about the risk of moving firewood.
  5. Support the voluntary and regulatory efforts.

Voluntary Strategies:

  1. Large-scale producers and retailers adopt best management practices.
  2. National producers and retailers adopt an industry-run national certification program with labeling and recordkeeping requirements based on best management practices.
  3. Public and private campgrounds make local or treated firewood available.
  4. Firewood consumers and small-scale local producers adopt best management practices.

Regulatory Strategies:

  1. APHIS should promulgate regulations for the interstate movement of firewood as soon as possible with requirements for labeling, recordkeeping and treatment based on best management practices.
  2. States should publish intrastate movement regulations with requirements similar to the Federal regulations for labeling, recordkeeping and treatment as needed. Moving firewood 50 miles or less would be exempt from intrastate regulations provided this does not violate any quarantine that may be in place.
  3. State, Federal, and private parks, forests and campgrounds should institute policies that encourage campers to use local firewood and to not move firewood out of the local area.

What has been done over the six and one-half years since the Strategy was released?

There has been tremendous progress on the outreach and voluntary strategies, with the Nature Conservancy’s Don’t Move Firewood program providing support and advice.  However, these voluntary programs are inadequate without regulatory backup.

There has been less progress on the more formal certification and regulatory strategies proposed in 2010.

Geoff Friedman – a firewood producer based in northern California – reports that he has developed the software for a certification program and worked with producers to get their acceptance. However, implementing the required wood treatments and – especially – staffing a third-party certification program – would raise the cost of firewood by 50%, according to Friedman. The major retailers which sell packaged firewood – the “big box stores” – are not willing to adopt the program because of this increased cost. In the absence or regulations requiring treatment of firewood, the program has stalled. (In the East, many states already regulate firewood. However, those states’ treatment requirements vary. Friedman seems to believe that this challenge can be worked out.)

APHIS has not adopted national regulations and does not appear to be on the verge of doing so. I believe APHIS wanted to tie its regulations to the certification program that has now stalled. Eleven of the 50 states currently have their own state-specific regulations limiting the movement of firewood from other states into their state. Only two more states are known to be potentially considering legislation in 2017. Many — but not all — federal agencies have now engaged on discouraging visitors from bringing their own firewood (see above). Some National parks actually restrict visitors bringing firewood to wood that is certified by USDA – including the park with the highest number of visitors, Great Smoky Mountains National Park. However, Yosemite and other National parks in California are not among them. And these are vulnerable to goldspotted oak borer and  the polyphagous or Kuroshio shot hole borers (see species write-ups here).

Worse, APHIS is actively moving toward dropping regulations trying to prevent spread of the emerald ash borer (see species write-up here). APHIS argues that with EAB now present in 30 states (although in many cases, in only one or a few counties), it is too late to try to prevent the insect’s further spread. The regulatory effort is using resources that would be better put to other strategies, such as expanding the biocontrol program. I concede that funding is tight, and likely to be cut further; and that other approaches – and other pests! – need attention.

However, the legal and logical foundation for nearly all state regulations governing firewood is the emerald ash borer. The promised federal regulation and certification program also rest primarily on the EAB risk. Many states – as well as APHIS – must base their regulation on one or more specific pests. Will these state regulations and promised federal programs survive the loss of the federal EAB regulatory program?

In any case, we are a long way from what is needed to get control of the firewood pathway. Each of the “lower 48” states should have an external quarantine. Hawai`i might need one too, if it imports firewood. (Hawai`i does import other types of risky wood products, including Christmas trees.)  Also, all 50 states need internal restrictions on the distance firewood is moved. So far, only a fraction have them.

The incoming Trump Administration strongly objects to regulations, so it is highly unlikely that we will see progress on these matters in the near future.



Koch, F.H., D. Yemshanov, R.D. Magarey, and W.D. Smith. 2012. Dispersal of Invasive Forest Insects via Recreational Firewood: A Quantitative Analysis J. Econ. Entomol. 105(2): 438-450 (2012);


Posted by Faith Campbell

Leigh Greenwood helped check the facts and dates mentioned in this blog


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

When will invasive species get the respect they deserve from conservationists?

i`iwi birdblogger i`iwi in Hawai`i

photo from; used with permission


Evidence is growing that invasive species are among THE major threats to conservation goals worldwide.

In 2015 the IUCN called invasive species the second most significant threat to those World Heritage sites around the world that have outstanding natural values. (Poaching is the greatest threat.) My October 21, 2015 blog showed that the IUCN report actually underestimated the impact of invasive species. I listed briefly the principal invaders in several U.S. National parks. Earlier blogs criticized the National Park Service for failing to regulate the movement of firewood (August 2015) and described the invasive threat to Hawai`i (earlier in October 2015).

Now a second study shows invasive species are a principal driver of species extinction. The authors assessed the prevalence of alien species as a driver of extinctions among plants, amphibians, reptiles, birds, and mammals (which are the best-studied taxa) post-1500 AD. Overall, 58% of extinct or extinct-in-the-wild species had been driven to extinction at least in part by invasive species. Invasive alien species are the second most common threat overall. Indeed, invasive species are the most common threat for vertebrate extinctions (62% of extinct or extinct-in-the-wild species faced threats from invasive species). Invasive species ranked fourth as a cause of extinction for plants: 27% of listed plant species were threatened by invasive species.

For those species with just a single driver of extinction, invasive species is the cause for 47% of mammals, 27% of birds, 25% of reptiles, and 17% of plants. In no case were invasive species identified as the sole threat to an amphibian species – although invasive species are their second highest threat.

Although the paper lists invasive species as second, their threat was virtually identical to that of “overexploitation”, the threat ranked first. That is, 124 out of 215 species studied were threatened at least in part by invasive species; 125 were threatened by overexploitation.

Other principal threats were overexploitation, agriculture, aquaculture, and – in the case of plants – residential and commercial development. Categories related to habitat loss ranked surprisingly low. Only 61 of the 215 cases listed agriculture and aquaculture as threats.

The authors reflect on whether invasive species are not themselves causal agents of extinction, but rather symptoms of the real causes, especially habitat destruction. They conclude that that is unlikely.

Instead, they suggest that invasive species impacts might often be underestimated, as many interactions – especially those between alien parasites and native hosts – are very hard to detect.

Not surprisingly, 86% of island endemic species had invasive species as one extinction driver. Nevertheless, continental organisms are also threatened — 14% of alien-related extinctions have been of species with mainland populations. These include eight amphibians, five birds, and six mammals. Most of these invader-threatened mainland organisms are from the Americas

Among the approximately 30 alien taxa named as extinction drivers are rats, cats, and trout as threats to other vertebrates such as birds and mammals. All three were also ranked highly as damaging invasives in the earlier IUCN report on World Heritage sites. Diseases – especially chytridiomycosis and avian malaria – were causal agents of extinction for amphibians and birds. Several herbivores – especially goats, sheep, and European rabbits – and alien plants were drivers of extinction for plant species.

Of course, outright extinction is not the only damage to biological diversity caused by invasive species. American chestnut, Fraser fir, and redbay are not extinct, but their ecological role has been virtually eliminated as the vast majority of these forest trees die off. Other tree taxa are on same road – ash and eastern hemlocks across wide expanses of their ranges; tanoaks; whitebark pines …

Invasive species pose major threats to biological diversity and other conservation goals. These damages are on top of the acknowledged threat of invasive species to agriculture, forestry, or economic groups. (See, for example, Lovett et al. 2016 discussed in my previous blog.) The role of invasive species in extinction described in this new paper suggest a long-standing bias among conservationists’ priorities. Too often, we have focused on species threatened by overexploitation – which is such easier to see and involves an obvious “villain”.

Nevertheless, a host of practical suggestions have been put forward to address the root causes of species introductions and spread. Often, these ask some or many of us to stop doing what we have been doing. But much meaningful conservation action requires someone to accept limits or to make sacrifices.

Will the conservation community – including grant-making foundations, federal and state agencies, and the many conservation non-governmental organizations ranging from the IUCN to local groups – now take up the challenge of implementing suggested actions and actively advocating for the funding needed for practical steps that will begin to bring this threat under control?



Bellard C, Cassey P, Blackburn TM. 2016 Alien species as a driver of recent extinctions. Biol. Lett. 12: 20150623. /


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

Available at


Posted by Faith Campbell

Feral Hogs: numbers climbing, threats to soils & ecosystems increasing, no control in sight

Introduced wild hogs (Sus scrofa) threaten ecosystems across the continent and on islands ranging from Hawai`i to the Caribbean.

large_hog_damage (MO)  feral hogs in Missouri

Pigs are the ultimate survivors – highly adaptable and prolific. Most of the damage is done by their rooting for plant parts and invertebrates in the soil, and by wallowing to cool themselves and fend of biting insects. Depending on soil type (density, moisture level, compaction), pigs may root to depths of three feet below the surface (USDA APHIS EIS).

Feral hogs consume primarily plant matter. They prefer hard mast – e.g., acorns, beechnuts, chestnuts, or hickory nuts. Pigs can be formidable competitors with native wildlife for this nutritious food. Feral hogs also eat algae, fungi, invertebrates such as insects, worms, crustaceans, and bird and reptile eggs. In addition, they feed on small animals, including reptiles, fish, amphibians, ground-nesting birds, and young of wild game and domestic livestock. They even feed on larger animals – although it is not clear whether they kill such animals or only scavenge their carcasses (USDA APHIS EIS).

Since pigs lack sweat glands, they wallow in water and mud to cool off. Some wallow sites are used for years. Adjacent areas are usually denuded of vegetation and the soils are compacted. Wallows are commonly located in or adjacent to riparian or bottomland habitats (USDA APHIS EIS).

Despite the apparent damage, only a few studies address the feral hogs’ impacts on soil structure, chemistry, bulk density and nutrient cycling. The conclusions of those studies are mixed (USDA APHIS EIS).

In Great Smoky Mountains National Park, feral pigs are reported to “plow up” areas in search of bulbs, tubers and wildflowers and to consume small mammals, snakes, mushrooms, bird eggs, and salamanders. (The Smokies are a center of endemism for salamanders.) Wallows are said to contribute significantly to stream sedimentation, thereby harming aquatic life.
Furthermore, feral hogs contribute to both human and animal disease. Their feces contaminate water and soil with coliform bacteria and Giardia which are both a threat to human health. Some of the wild pigs also carry Pseudorabies, a disease that is almost always fatal to mammals, including such important wildlife species as black bear, bobcat, elk, white tailed deer, red fox, grey fox, coyote, mink, and raccoon. Pseudorabies from wild boar can survive in humid air or water for up to seven hours and in plants, soil, and feces for up to 2 days.

Unfortunately, the United States’ population of introduced wild pigs has dramatically increased since 1990. People are to blame. map

States with feral hog populations; provided by John Mayer, US Department of Energy, Savannah River National Laboratory

According to John J. Mayer, the number of states with established wild boar populations has risen from 19 in the 1990s to 37. The total number of feral hogs has risen from an estimated 1 to 2 million animals to a range of 4.4 to 11.3 million (Mayer).

The overwhelming majority of the feral hogs is found in only 10 states –AL, AR, CA, FL, GA, LA, MS, OK, SC, TX. Texas has the largest numbers, 30 to 41% of the U.S. total, depending on whether one is counting the states’ animals by mean, maximum, or minimum estimates.

Why have people transported feral pigs to so many new places over the last 20 years? Largely because hunters wanted an exciting game animal to pursue (USDA APHIS EIS; Mayer). In Tennessee, populations of feral swine (probably released by farmers to forage for themselves) were relatively stable and confined to only a few counties from the 1950s through the 1980s. However, since a statewide, year-round, no bag-limits hunting program was instituted in 1999, pig populations have expanded rapidly. In 2011, nearly 70% of counties had pockets of feral swine (USDA APHIS EIS).

But hunting is not an effective means of controlling the animals’ populations and damage. Mayer reports that sport hunters remove about 23% of a wild pig population annually. Models demonstrate that 50 – 75% of a wild pig population must be removed annually, year after year, in order to reduce or eradicate that population (J.J. Mayer pers. comm]

Mayer says there are currently no effective management tools or options to reduce or control feral hog populations in most situations. I note that the Hawaii Volcanoes and Haleakala National parks have been able to eradicate feral pigs through determined efforts.

Missouri is one state that is tackling feral hogs aggressively. In January, the Missouri Conservation Commission approved changes to the Wildlife Code of Missouri  that would prohibit the hunting of feral hogs on lands owned, leased, or managed by the Missouri Department of Conservation. A public comment period on the proposed regulation change will run from April 2 through May 1. After considering the citizen input and staff recommendations, the Commission will reach a decision whether to finalize the new regulation – probably in September. (Missouri has quite extensive material on feral hogs posted here
Meanwhile, the Missouri Department of Conservation has reached out to several partners to strengthen its increase the number of feral hog traps it can place and enhance communication to the public. These partners include such agricultural organizations as the Missouri Farm Bureau and Missouri Pork Producers; and such conservation organizations as the National Wild Turkey Federation and two quail associations.

New York has gone farther; it has adopted a policy of eradicating Eurasian wild boar from the state. To achieve this goal, the state in October 2013prohibited importing, breeding, or releasing Eurasian boars. As of September 2015, it has been illegal to possess, sell, distribute, trade or transport Eurasian boars in New York. Hunting or trapping of Eurasian boars is illegal except for law enforcement officers, farmers, and landowners authorized by the Department of Environmental Conservation (DEC). The hunting ban was adopted in order to minimize breakup of sounders so as to facilitate eradication trapping by trained conservation officers. For more information, visit the DEC website.

Mayer, J.J. 2014. Estimation of the Number of Wild Pigs Found in the Unted States. August 2014 SRNL-STI-2014-00292, Revision 0.

U.S. Department of Agriculture Animal and Plant Health Inspection Service
Final Environmental Impact Statement. Feral Swine Damage Management: a National Approach May 27, 2015
Posted by Faith Campbell

New IUCN report notes invasive species threat to World Heritage Sites – Including U.S. National Parks

The World Conservation Union (IUCN) has just released a report, IUCN World Heritage Outlook 2014 (for press release, click here; for the full report, click here)
that names invasive species as the second most significant threat World Heritage sites with outstanding natural values. (Poaching is the greatest threat).

World Heritage sites have “outstanding universal values” – either natural or cultural. Natural sites are areas either of exceptional beauty or representative of major stages of Earth’s history, significant ongoing ecological processes, or significant habitats for biodiversity and threatened species.

The 2014 assessment examined 229 natural World Heritage sites and found that 104 are affected by invasive species. Unsurprisingly, island sites are especially heavily impacted. Two-thirds of the affected island sites (24 out of 36) are in the tropics.

The most widespread or common invaders are plants; they are named in 55 of the 104 affected sites. Invasive vertebrate animals affect at least 12 sites. These frequently include fish (mostly trout), cats, and rodents (especially rats).

The report calls for effective management strategies to protect the World Heritage sites. Such strategies include well-defined plans as well as strict bio-security measures, including limiting materials entering the site or the eradication of problem-causing species. Ideally, these actions involve local communities. Among the 104 natural World Heritage areas affected by invasive species, 87 have management projects addressing at least some invasive species or related issues.

According to the report, future invasive species management will be even more challenging, especially because of climate change. Climate change, itself, could become the biggest threat to natural sites in future.

30 dead swt bay 

dead sweetbay in Big Cypress National Preserve, Florida

The United States has 21 World Heritage sites. Nine were chosen for their outstanding natural values. These include the following National parks: Everglades, Grand Canyon, Great Smoky Mountains, Hawaii Volcanoes, Redwood, Yellowstone, and Yosemite National parks; and – jointly with Canada – Kluane / Wrangell-St. Elias / Glacier Bay / Tatshenshini-Alsek and Waterton-Glacier National parks.

Several of these natural wonders are well known to be threatened by invasive species – including some tree-killing insects and pathogens.

Everglades National Park. In Everglades, pythons have decimated populations of small to medium native mammals. Lionfish are killing vast numbers of fish in the shallow bay. Numerous invasive plants, especially Australian pine, Melaleuca, Brazilian pepper, and old world climbing ferns transform the natural sawgrass prairie and mangroves. Some, e.g., Melaleuca, are under control thanks to persistent effort over decades.

Laurel wilt has almost eliminated swamp bay trees from the hammocks. Bromeliad weevil has killed many bromeliads in 12 genera (of the 16 present in Florida).


Tillandsia utriculata bromeliad in Florida

Great Smoky Mountains National Park. The outstanding biological diversity of the forested Great Smoky Mountains National Park has been severely undermined by chestnut blight, hemlock woolly adelgid, balsam woolly adelgid; and is now under attack by more recent invaders, including beech bark disease, emerald ash borer, and thousand cankers disease of walnut. Descriptions of all these pests are available here. At ground level, feral hogs damage plants, soil-dwelling invertebrates and small vertebrates, even birds. Rainbow trout compete with native trout in the streams. More than 380 non-native plants compete with the native species. The Park’s website features another invader, the Asian jumping worm (Amynthas agrestis), which has been introduced through bait.

The Great Smoky Mountains are the center of biological diversity for salamanders which are likely soon to face danger from the “Bsal” pathogen – unless the Fish and Wildlife Service acts to restrict imports of salamanders by the pet trade. See how CISP tries to counter this threat.

Hawaii Volcanoes National Park. As I wrote in my blog of October 7, Hawaii Volcanoes National Park is fighting feral hogs, goats, and a plethora of invasive plants (the Park’s flora contains nearly twice as many exotic flowering plants as native species). The Park’s birds are threatened by two non-native diseases, avian pox and avian malaria. As noted in the earlier blog, Hawaii Volcanoes has also been invaded by koa wilt and `ohi`a rust; and is about to be invaded by `ohi`a wilt.

Web-based information from several parks in the western part of the continent focuses on the threat from invasive plants: Grand Canyon, Olympic, Yellowstone, and Yosemite. Redwoods National Park notes the damage caused by sudden oak death to its principal hardwood species, tanoak. Yellowstone National Park has a website describing its whitebark pine forests and mentioning that up to 30% of the taller whitebark pines have been attacked by white pine blister rust; I could find little information about the disease’s impact on the Park’s limber pines, which are also susceptible.

Yosemite National Park has a website with a table listing 16 non-native insects and pathogens that could threaten trees in the park. White pine blister rust is already present in the Park’s sugar pines. I am pleased to see that the website features goldspotted oak borer and the risk of pest introduction via firewood. I just wish Yosemite actually prohibited visitors from bringing firewood into the Park! And carefully restricted commercial suppliers! I addressed Yosemite’s failure to protect itself in my blog of 10 August.

The National Parks Conservation Association is the principal NGO that advocates for protection of the National parks. It issued a report in 2008 that found invasive species were a limited concern in 90% of the parks evaluated, a widespread or chronic concern in 38%. In Hawaii Volcanoes specifically, the natural resources were ranked in “poor” condition due primarily to non-native plants and animals.

Many individual parks have “Friends” groups ….

I ask these groups to help the National parks counter invasive species. To be effective, they need to go beyond the many volunteer “weed pulls” and outreach programs educating park visitors who might transport invasive species (for example, boaters and fishermen who can spread New Zealand mudsnails, rock snot, and invasive mussels; and campers who carry firewood that can transport pests). I ask them to also lobby for policies that would prevent invasions and for increase funding for the parks’ resource management programs (the programs that tackle invasive species). I suggest specifically that supporters of National parks advocate for improvements in programs run by the USDA’s Animal and Plant Health Inspection Service or the U.S. Fish and Wildlife Service.  These agencies, more than any other, determine whether prevention succeeds or fails.


Posted by Faith Campbell

Hawaii’s unique forests now threatened by insects and pathogens – APHIS & State should act

We have known since Darwin that oceanic islands can be cradles of speciation & endemism. Hawai`i exemplifies the phenomenon. Ninety-eight percent of native flowering plants are endemic (Cox). The density of native insect species in Hawai`i is higher than on mainland North America (Yamanaka).`ohi`a

We have known since Elton or earlier that oceanic islands are highly vulnerable to bioinvasion because their unique species did not evolve defenses against predation, herbivory, competition, or diseases; or the ability to adapt to changed soil chemistry or increased fire frequency.

Chapter 8 of the Office of Technology Assessment study of harmful invasive species states:

“Hawaii has a unique indigenous biota, the result of its remote location, topography, and climate. Many of its species, however, are already lost, and at least one-half of the wild species in Hawaii today are non-indigenous. New species have played a significant role in the extinction of indigenous species in the past and continue to do so. Hawaii, the Nation, and the world would lose something valuable as the indigenous fauna and flora decline.”

I apologize for not addressing the disasters wreaked on Hawai’i’s fauna and non-arboreal flora by invasive mammals and birds, plants, and such animal diseases as avian malaria and avian pox. For more on these topics, see the other sources listed below and the websites maintained by the Hawai`i Invasive Species Council and Coordinating Group on Alien Pest Species. Cox notes that alien species span all trophic groups and threaten the complete replacement of the native terrestrial biota.

Outside of land clearing for ranches and other uses, much of the damage to Hawaii’s native forest trees has been caused by introduced mammals – especially pigs and goats; and invasive plants. Few of the enormous number of non-native insects that have established in Hawai`i appear to have attacked native trees. More than 2,600 non-native insects have been introduced; their number equals three-quarters of the NIS insects established in North America, yet Hawai`i constitutes less than 0.01% of the area of North America. The ratio of non-native to native insect species is higher for Hawai`i than for the other geographic areas studied by Yamanaka and colleagues (mainland North America, “mainland” Japan, and two offshore Japanese islands) (Yamanaka).

More than 13% of the non-native insects (=~350) in Hawai`i were introduced intentionally for biological control of agricultural pests and non-native plants (Yamanaka). Cox, Elton, and the Office of Technology Assessment discuss briefly the sometimes damaging effects of these deliberate introductions.

I am aware of only one NIS insect that has seriously threatened a native tree species: the Erythrina gall wasp, which killed many native wiliwili trees as well as lots of introduced coral trees planted in towns and as windbreaks. Biocontrol agents have helped prevent continuing damage from the gall wasp.

Disease pathogens have so far proved greater threats to Hawaiian native trees than introduced insects. Koa wilt is killing koa, especially at lower elevations. It is not certain whether the pathogenic Fusarium fungus is introduced or native; it has been found on all four major islands. Koa is second only to `ohi`a (see below) in abundance in mid to upper elevation Hawaiian forests. It is extremely important ecologically and culturally (koa was the tree from which large, ocean-going canoes were made). Koa also has a wood valued for a range of uses.

`Ohi`a lehua is the most widespread tree on the Islands, dominating approximately 80% of Hawai`i’s remaining native forest (about 965,000 acres, 1500 square miles). These forests are home to Hawai`i’s one native mammal (Hawaiian hoary bat) and 30 species of forest birds (Loope and LaRosa). One threat to `ohi`a comes from `ohi`a or eucalyptus rust.  Detected in April 2005, it had spread to all the major islands by August. Fortunately, the strain of `ohi`a rust established in Hawai`i is not very virulent on `ohi`a, but it has killed many plants of an endangered native shrub, Eugenia koolauensis and in Australia it has killed many plants in the Myrtaceae family. Hawaiian conservationists worry that a different, more virulent, strain might be introduced on plants or cut foliage shipped to the Islands from either foreign sources or the U.S. mainland.

A new, apparently more damaging, pathogen was detected in 2010. This new disease is caused by a new strain of a fungus long present in Hawai`i but not previously known to attack trees — Ceratocystis fimbriata. Already, the disease has killed 50% of the `ohi`a trees in several scattered locations totaling 6,000 acres on the southeast lowlands of Hawai`i (the “Big Island”). Tree mortality is now nearing the boundary of Hawaii Volcanoes National Park. Hawaii Volcanoes pioneered methods for controlling invasive pigs and plants that threatened to destroy the Park’s forests. Through 40 years of sustained effort, Hawaii Volcanoes has brought those threats under control. Now the Park faces loss of its invaluable `ohi`a forest to this pathogen – which will be infinitely harder to keep out of the Park.

The Hawai`i Department of Agriculture has adopted an emergency regulation aimed at preventing transport of infected wood or tree parts from the Big Island to other islands.

Although tree-killing insects and pathogens have so far not been as damaging in Hawai`i as might be expected, the Islands are highly vulnerable due to the large volumes of cargo and people from around the globe which land on the Islands and the few tree species native there. The Erythrina gall wasp has island-hopped from the east coast of Africa to Hawai`i and many islands in between. `Ohi`a rust is native to tropical America and probably reached the islands on cut stems used in floral decorations. It is unknown where the Ceratocytis fimbriata strain evolved or how it reached Hawai`i.

USDA APHIS is responsible for preventing introduction of new plant pests to Hawai`i from non-U.S. jurisdictions (as well as from Guam). APHIS has traditionally paid little attention to plant pests that are thought likely to threaten “only” Hawai`i but not plant (agricultural) resources on the mainland.

Hawaiian authorities are responsible for preventing introductions from the Mainland – but they struggle with inadequate resources to address the huge volumes of incoming freight and they sometimes hesitate to act. (Hawai`i Department of Agriculture considered restricting shipments of foliage in the Myrtacea to minimize the risk of introduction of a new strain of `ohi`a rust, but in the end did not adopt such a measure.)

Hawai`i’s unique biota is an irreplaceable treasure. All Americans should act to prevent introduction additional introductions to the Islands.

Cox, George W. Alien Species in North America and Hawaii Impacts on Natural Ecosystems 1999
Elton, Charles S. The Ecology of Invasions by Animals and Plants 1958; see especially Chapter 4: The Fate of Remote Islands
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U.S. Congress Office of Technology Assessment. 1993. Harmful Non-Indigenous Species In the United States. OTA-F-565; available at

Yamanaka, T., N. Morimoto, G.M. Nishida, K. Kiritani, S. Moriya, A.M. Liebhold. 2015. Comparison of insect invasions in North America, Japan and their Islands. Biol Invasions DOI 10.1007/s10530-015-0935-y

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