Frequently Asked Questions

An invasive species is a species that meets the following three criteria:

1. The species is growing outside of its natural range.
2. The species is spreading rapidly.
3. The spread of the species causes some kind of ecological, economic, or social harm.

Examples of harm include the loss of native biodiversity, impacts on industry profits, and the introduction of allergens, toxins, or physical barriers to an area. 

Not all introduced species are invasive, and in fact, most of them aren’t. A species that does not naturally occur here and does not spread rapidly or cause harm is referred to as a non-native, exotic, introduced, or alien species (often interchangeably). A great example of a non-invasive exotic species is the potato.

By definition, a native species cannot become invasive. Only introduced species, those that do not occur naturally in the area, can be considered invasive. These native but problematic species are instead referred to as weeds, pests, or diseases. For example, all invasive plants can be considered weeds, but not all weeds can be considered invasive plants. Work with native pests, weeds, and diseases falls outside of the scope of the PEIISC’s work.

An example of a native species that is often mistakenly called invasive is the striped bass — potentially problematic for fisherman, but native to the area, and thus not considered an invasive species. Other examples include spruce budworm, spruce bark beetle, many mosquito species, and poison ivy.

Some of the island’s most common species are invasive. Could you imagine a PEI landscape without lupines or dandelions? These widespread invasive species are considered beyond anyone’s capacity to control, and are now known as “naturalized”.

Some of the invasive species the PEIISC receives the most questions about from the public include Japanese knotweed,  Reynoutria japonica, Japanese beetle, Popillia japonica, and woodland angelica, Angelica sylvestris. Some invasive species the PEIISC is currently focused on eradicating include giant hogweed, Heracleum mantegazzianum, and Scotch broom, Cytisus scoparius. These plants are selected because their distribution is limited and their potential impacts are significant, making them prime targets.

Some invasive species not yet found on PEI have the greatest potential impact. These include the emerald ash borer,  Agrilus planipennis (buprestid beetle that has caused mortality in 99% of the ash trees it has infested and may cause future extinction of native true ash species),  hemlock woolly adelgid, Adelges tsugae (aphid-like insect that has caused mortality in over 90% of the Eastern hemlock trees it has infested), and oak wilt, Bretziella fagacearum (fungal disease of oak that causes rapid mortality in Northern red oak, our provincial arboreal emblem). By taking preventative measures, such as not moving firewood, we can help protect PEI from these potential future invaders.

Invasive species impact ecosystems in many ways. Where they displace native species, they most often do not offer the same nutritional value to wildlife as would the displaced native species. The same can be said regarding providing habitat to wildlife.

PEI today is essentially a manmade landscape thanks to intensive farming and resource collection since European colonization. Due to these practices, our landscape today unfortunately presents a perfect opportunity for many invasive species to move in. This is because disturbance generally favours the establishment of invasive species over native species.

Many invasive species are known as “ecosystem engineers”. This means that they have a propensity to drastically alter the environments in which they grow to favour their own growth. Impacts include changes in water movement (hydrology), changes in sedimentation rates, changes in the accessibility of a landscape, changes in water quality, and more.

Some invasive species kill native species by feeding on them directly or through overcompetition. This can cause drastic shifts in ecosystem composition including changes in temperature, moisture levels, food webs, and more.

Many invasive species increase costs for agriculturists by reducing yields and increasing pesticide usage.

Many invasive species impact fishermen, including European green crabs, tunicates, oyster thief, and more. Fishermen may experience harvesting complications, increased management costs, and reduced yields as a result of invasive species activity.

Many invasive species impact foresters by reducing the quality and salability of wood products. To comply with ordinances, foresters may also experience increased costs from treating wood products when regulatory measures to prevent pest spread are implemented.

Invasive species can impact tourism by impacting wildlife and ecosystems, as tourists often put high value on natural and scenic beauty.

Some of the most common sources of allergens are from invasive species. As many invasive species have extremely high reproductive rates, they can produce a large abundance of pollen. In particular, mugwort, Artemisia spp., and broadleaf plantain, Plantago major, are known to be major causes of hay fever.

Some invasive species reduce the accessibility of natural spaces. Species like multiflora rose, Rosa multiflora, can create impenetrable thickets, reducing the ability of locals and visitors to engage with nature.

Some invasive species make people scared to get outside. Species like giant hogweed, Heracleum mantegazzianum, have significant toxicity and can make people nervous about using the great outdoors.

Some invasive species, like the zebra mussel, Dreissina polymorpha, (not yet present on PEI), are known to clog infrastructure like hydroelectric power plants.

Many more effects can be seen as well, such as increasing erosion rates.

Invasive species identification is the first step towards managing invasive species impacts. Without proper ID, you may use the wrong tools and methods or mistakenly target native or non-problematic exotic species. Please note that many invasive species have native lookalikes. These native lookalikes may be mistakenly destroyed due to their association with invasive species. This is another reason why firm ID is needed before action is taken.

To identify a species, begin by either collecting a sample or taking some photos. Alternatively, you can work with the species directly in the field, although this requires either print resources or internet access to obtain information. When taking photos, be sure to take clear, detailed shots of the entire organism, as well as close/ups of distinctive features like flowers, seeds, etc. that may assist you in identification later on.

To identify an invasive species, you have a wide variety of great resources at your disposal.

For idenification of species using specimens, we recommend using a ruler and a loupe (or magnifying glass). Size is very important in identifying species, and key features may be too small to be seen with the naked eye. You can then use the resources listed above to assist you.

In short – yes! The PEIISC would be happy to assist with identification. First of all, we recommend attempting identification yourself. See the above question “How do I identify an invasive species?” for more information.

When contacting the PEIISC for identification, you should always include photographs of what you’ve seen. Without pictures, a solid ID confirmation is difficult. Take pictures of the organism, any damage it may have caused, its surrounding environment, and ideally some closeups of distinctive features that will assist our staff in identification. For mobile adult insects, you may want to capture the insect before attempting to photograph it.

Send your information (including the location, the date of your find, and any other relevant information) and photos to peiinvasives@gmail.com. We will reply (usually within a week) with our assessment.

If you cannot include photographs, staff may (circumstantially) be able to come for a site visit. In these cases, be as descriptive in your wording as possible when describing the creature in your report.

First, check to see if the organism is featured on our species profiles (https://peiinvasives.com/invasive-species/) or invasive species priority lists (plants: https://peiinvasives.com/pei-invasive-species-plant-list/, insects and diseases: https://peiinvasives.com/invasive-insect-and-disease-priority-list/).

If the species is not on PEIISC listings, next determine whether the species is native or introduced. We recommend using the ACCDC’s conservation ranks listings for the province, which can be found here: https://accdc.com/en/ranks.html. Please note the website’s security certificate is out of date, and your browser may warn you of an unsafe connection. Click past this notice to access the website. It is safe to use despite the outdated security certificate.

Once you have navigated to the website, scroll down to the Prince Edward Island listings and select the taxonomic group of concern to bring up the complete listing of known species occurrences for PEI. After selecting the relevant list, use the find feature (hold CTRL or CMD and press F) and search the page for the scientific (latin) name. To find the scientific name, I recommend using a google search. If the species appears in the ACCDC listings, scroll right along the row to the noteRank column. If the species is listed as Exotic in this field, it is not native to PEI, and thus may be invasive. If this is not noted, the species is likely native. If the species does not appear in the ACCDC listings, you may have observed a new species record for PEI, or your identification may be off.

Remember, not all exotic species are invasive. If the species is found to be exotic in the ACCDC listings, or if you are having difficulty navigating the ACCDC website, invasiveness can usually be easily determined by a simple online search. Find out the species’ scientific name, and then search the web for “(scientific name) invasive species”. Using the scientific name is important, as common names vary. If there is information found from reputable conservation organizations indicating its invasiveness, this is a good sign that the species is likely invasive on PEI too. Make sure the organism is not native to PEI before accepting its invasiveness — sometimes organisms that are native to PEI are considered invasive elsewhere, such as Canada goldenrond. This means you should try and source your information from local soures as much as possible.

Sometimes, a species’s impacts and invasiveness are as yet unstudied. In this case we don’t know how the organism will behave in the region. Some species that are invasive in one region may not behave as such in another region.

Finally, if you are still unsure, you can always confirm with the PEIISC at peiinvasives@gmail.com

The best way to dispose of invasive species can vary based on site conditions, the species managed, your personal goals, etc. For detailed disposal directions, visit our disposal webpage: https://peiinvasives.com/disposal/

For additional information not found on the above webpage, contact the PEIISC for directions at peiinvasives@gmail.com. Include in your inquiry the species you are managing, how much material there is, and any other relevant information.

No invasive species management effort is complete without properly completing disposal. Every invasive species has a recommended disposal procedure which may vary based on site conditions, time of year, and life stage. If you do not properly dispose of the invasive species, the problem may reappear, or worse: you may cause further spread both to your own property and elsewhere. This makes following best practices and properly disposing of invasive species essential to a successful control effort. For more information on disposal, see our invasive species profile pages (https://peiinvasives.com/invasive-species/) or our disposal information page (https://peiinvasives.com/disposal/).

Invasive species can be reported to the PEIISC in a variety of ways. The recommended procedure can vary based on the species priority and your goals. In any invasive species report, you should include the following:

• What you saw
• When you saw it
• Where you saw it
• Photos
• If available, any other relevant information

Consider this flow chart when deciding how to best report the observation:

For invasive plant reports:

For invasive insect or arachnid reports:

Reporting platforms:

• iNaturalist
  • www.inaturalist.ca or the iNaturalist app is a great tool for identifying and sharing observations. Simply make an account and visit the website or download the app on your smartphone. Include as much information as you can in your report.
  • You will benefit from an extensive community of naturalists and local experts who are active on the platform.
• EDDMapS
  • www.eddmaps.org or the EDDMapS app is a great too for reporting invasive species. This tool accepts only invasive species reports. Make an account and ownload the app on your smartphone or visit the website to make reports. PEIISC staff are local verifiers and will review your report directly.
• Directly to the PEIISC
  • The PEIISC can process reports directly through the following submission platforms:
    • By email, peiinvasives@gmail.com
    • By facebook or instagram messenger (www.facebook.com/PEIInvasives, @peiinvasives)

Yes! The PEIISC would rather receive 100 false reports than miss one report that turned out to be important. There is no such thing as a bad report, and never feel embarassed to ask us for help. It’s what we’re here for!

If we don’t know about it, we can’t act on it, and thus reporting is foundational to our success as an organization. We are also a very small staff, so the more eyes we have on the landscape looking for invasive species, the better! Tracking the distribution and spread of invasive species across the landscape helps us decide where, how, and when to act, and informs the actions of other conservation organizations as well. Reporting allows us to best direct our limited resources to have the broadest possible positive impact.

This starts by understanding the distribution of the species (where is it). Then we attempt to determine how the species is being moved around (by what pathway is it travelling). Next, we review any precedents set: Have there been any successful efforts to control this species elsewhere, and if so what were their methods?

Thankfully PEI is not often ground zero for new invasive species introductions, so there is usually some information available from other jurisdictions. PEIISC technicians keep up to date on the general news in the invasive species field to know what species are on the horizon. Each species has its own unique set of recommended best practices for management, but these can vary by region. For this reason, getting out into the field to determine the species’ behaviour on PEI specifically can also be helpful.

This will depend on the species and how long it has been established in other jurisdictions. The council is a group of interested stakeholders including organizations like the CFIA, Island Nature Trust, Department of Fisheries and Oceans, and more. This network allows us to quickly connect with experts on particular species to make the best, most effective response to an invasive species.

Although our resources are limited by time, money, and staff availability, we try to budget these valuable resources such that our impact on invasive species control in the province is broadened. Without our partners, none of our work would be possible!

First and foremost the efficacy of organic controls is examined. These usually involve physical removal by some means (varying by species). Some species need to be dug out to remove all roots, some species need to be regularly mowed down without disturbing the roots, or some management programs may use covering (covering the invasive species with a thick dark-coloured material to prevent upward growth and photosynthesis).

The PEIISC does not make recommendations for the use of chemical controls at this time, though we recognize that they are necessary for certain conditions and certain species. When using chemical controls it is imperative that the manufacturer’s label and local legislation be followed during preparation and application.

Cultural controls, such as planting native competitors, turning the soil, grazing with animals, improving the health of native plant communities near infestation sites, and more can provide direct and indirect control of invasive species.

The main thing to remember is that each species is different and must be approached armed with the best, most up-to-date control information.

A novel tool for the management of difficult plants is available in Europe. This technology is branded “Rootwave” and it kills plants by electrocution, boiling the roots in situ. This method has proven extremely effective in the management of Japanese knotweed, one of the most tenacious invasive plant species known.

Anaerobic soil disinfestation is a method that uses an artificial anaerobic environment to promote microbial growth leading to decay of underground plant structures like roots and rhizomes. This may prove effective against tough perennials like Japanese knotweed.

Tools like the WeedErase AC use high-powered ultraviolet and infrared lights to kill weeds.

For the PEIISC’s operations, outreach is everything! By engaging the public in invasive species issues and suggesting minor behavioural changes that can help reduce the spread of invasive species, new invasive species introductions can be reduced. It is also more likely that an informed individual will take action to manage invasive species, report them, or spread the word.

Operationally, the PEIISC currently is only composed of three staff members, a coordinator and two technicians. Because we are only three, we couldn’t possibly visit every invasive species population on PEI let alone manage them all. The PEIISC focuses primarily on giving others the necessary tools and expertise to take on invasive species management projects on their own. Our organization also encourages others to report invasive species to us as they observe them. Again, our staff simply can’t be everywhere, so the more people looking out for invasives the better!

Getting out to schools and educational events to talk with people and learn more about what they are most concerned about (and where they need support) is very important as well. Youth will carry these messages with them as they grow up, improving their likelihood of engaging with invasive species issues as adults.

Due to our limited capacity, the PEIISC does not have much funding or availability to work on private property. That being said, our availability can often depend on the species of concern. Our primary focus is on species that have limited distributions on PEI. This is because newly established species are the least widespread, and there is the highest potential to completely eradicate the species on PEI. For newly introduced invasive species which have a serious potential impact, the PEIISC may be able to offer removal support.

For more common invasive species like Japanese knotweed, the PEIISC will usually not be able to offer in-person assistance. In these cases, the PEIISC would be happy to offer advice remotely to ensure you are making the most efficient and effective control technique. Contact us with a description of your project and resources, along with some photos of the site and species of concern. You may have success in reaching out to your local watershed group (though their hands are often full already) for help or by organizing a neighbourhood or community effort.

Some species the PEIISC is more likely to be able to help address in person:

• Giant hogweed, Heracleum mantegazzianum
• Phragmites, Phragmites australis ssp. australis
• Garlic mustard, Alliaria petiolata
• Yellow nutsedge, Cyperus esculentus
• Scotch broom, Cytisus scoparius
• Emerald ash borer, Agrilus planipennis
• Hemlock woolly adelgid, Adelges tsugae
• Oak wilt, Bretziella fagacearum

The “invasion curve” describes the stages of an invasion coupled with the most reasonable control strategy over time. As time goes on, and proportionally, the amount of infested area increases control costs increase and the likelihood of eradication decreases. This means that focusing on prevention and newly introduced invasive species is most effective and cost-efficient.

At the time of writing, you cannot legally force your neighbour to control invasive species on their property. The PEI Weed Control Act (https://www.princeedwardisland.ca/sites/default/files/legislation/w-02-1-weed_control_act.pdf) has provisions which would allow appointed weed inspectors to force individuals to manage noxious weeds on their property, but no such inspectors are appointed and only one plant has been designated as a noxious weed (purple loosestrife). The CFIA also has a Weed Seeds Order which prevents trade of seeds of regulated species (https://laws-lois.justice.gc.ca/eng/regulations/SOR-2016-93/FullText.html) but is not related to control of established ones.

Because of this lack of policy and enforcement, invasive species infestations that cross properties or exist outside of your own private property must be managed with the cooperation of the property owner. Any action taken to control invasive species outside of your own property must be confirmed and approved of by the property owner. Time to build community and meet your neighbours!

Periodically, opportunities arise for volunteers to assist with invasive species removal efforts. If you are interested in staying up to date on these opportunities and the PEIISC in general, follow us on social media or fill out this form to join the PEIISC Spotter’s Network: https://forms.gle/qpDDFTdTHoVeFQQp9

The PEIISC greatly appreciates your interest!