Blog & News

What is an invasive species?

Published on Saturday July 17, 2021
Authored by PEIISC

An invasive species is any species that is not native to an area, has a tendency to spread, and threatens the environmental, economic or social health of that area.  Native species have natural mechanisms that keep their populations within a sustainable range (i.e. predators, pathogen, competitors, etc.).  Invasive species are removed from their natural ecosystems and are no longer kept in check by their natural predators and pathogens.  This is one reason why invasive species often out-compete native species.

Just because a species is not native to an area, does not mean there is cause for concern.  Although the terms are often used interchangeably, only a small percentage of non-native species become invasive.

The invasive nature of introduced water lilies (Nymphaea odorata (exotic))

Why does it matter?

Invasive species can negatively affect our environment, our industries, our health and our ability to use natural areas for recreation.

The UN lists invasive species as the second greatest cause of biodiversity loss in the world.  Biodiversity refers to the number of different species of living things within a particular ecosystem or defined geographic area.  Loss of biodiversity affects everyone.

A loss of biodiversity can affect an ecosystem’s ability to function.  Everyday, ecosystems perform functions that are vital to all life, including: filtering air and water, cycling nutrients, photosynthesizing, etc.  Our health and well-being depend on these essential ecosystem functions.  If too many species are lost from an ecosystem, it may not be able to maintain these functions.

The diverse ecosystems we live in support our primary industries: agriculture, forestry and fishing.  The presence of invasive species can greatly affect these industries – for example, by increasing the need for herbicide in agriculture, increasing fire hazards in forestry, and increasing the effort required to harvest in fisheries.  If invasive species are not detected and eradicated early, their long-term effects can be devastating and irreversible.

One Island example of the devastating effect invasive species can have is the tunicate.  Tunicates pose a serious challenge for the mussel aquaculture industry in PEI.  They attach to mussel socks, spread quickly, and compete with mussels for food and space.  The fouling caused by the tunicates increases the cost of labour (for both the grower and the processor), and the cost of transportation and disposal.  Restrictions on the movement of shellfish from tunicate infested areas have been put in place.  For more information on aquatic invasive species on PEI visit Fisheries, Aquaculture and Rural Development.

In the short-term, invasive species can decrease your ability to enjoy hunting, fishing, bird watching, swimming and other recreational pursuits.  The longer we wait, the more expensive it will be to control invasive plants.

In 2000 (updated in 2004), the World Conservation Union collaboratively published a booklet identifying 100 of the World’s Worst Invasive Alien Species, of which about 13 currently exist in PEI.

Top: A diverse forest understory
Bottom: An understory dominated by periwinkle (Vinca minor)

What is happening on PEI?

Managing invasive species on PEI is challenging.  90% of the Island’s land mass is privately owned.  That means that most of the invasive species on PEI are found on private lands, and management of those species is entirely up to the landowner.

There are many groups, some represented on our Council, across PEI that are working to manage invasive species.  As a volunteer Council, we do not have the capacity to take on management projects.  However, we can offer management recommendations and guidance.  We have a collection of management fact sheets available, which you can find on our Resources page.

Prevention is our number one tool against invasive species and we have to be diligent.  To increase surveillance and awareness of invasive species on PEI, we started the PEI Invasive Species Spotters Network in 2015.  The Spotters Network is comprised of volunteers and professionals that are trained in identifying and reporting invasive species, particularly new or uncommon species.  One of the goals of the Spotters Network is to increase our ability to detect new invaders earlier, so that we may deal with them before they become widespread.

In a province such as ours where so many of us are dependent, directly or indirectly on primary resources such as fisheries and agriculture, it is important to be aware of and on the look out for new invasive species.

What can you do?

As a land owner there are many things you can do to prevent the spread of invasive species on your property:

  • Learn more about invasive alien species on PEI, including how to identify species of concern
  • Become a volunteer invasive species spotter by joining our Spotters Network!
  • Choose your plants with care.  If you don’t know what it is, reconsider
  • Choose native species whenever possible
  • Carefully inspect and clean clothing, gear, animals, and vehicles before visiting a new natural area
  • Do not transport plants, seeds or animals into or out of PEI
  • Never dump garden or pond waste in a natural area
  • When disposing of IAS, they should be placed in a clear plastic bag, clearly identified on the bag what it is, and taken to Island Waste Management Corporation’s Waste Watch Drop-Off Centers for incineration or deep burial.  Please refer to Island Waste Management’s sorting guide