Protecting Canadian Ecosystems Against Invasive Foreign Species

Essay, Climate, COVID-19, Anil Anand

The five largest mass die-offs in which 50–95% of species were eliminated occurred during the Ordovician, Devonian, Permian, Triassic, and Cretaceous periods. Most recently, human actions, especially over the past two centuries, have precipitated a global extinction crisis or the ‘‘sixth great extinction wave’’ comparable to the previous five. Increasing human populations over the last 50,000 years or so have left measurable negative footprints on biodiversity.1

The current global health crisis will provide many lessons, and warnings about our interdependence on the natural world, with each other, and the frailty of our economic and existential well being. A reminder of how unexpected and unintentional human intervention can lead to cataclysmic consequences. 

Despite the frailty of our planet, its uniqueness and complexity, our arrogance has imbued us with the belief that we are above and apart from the web of life, that we can manipulate, design, and exploit the planet, and do so with impunity, and a belief that our intelligence will provide the solutions to overcome any eventuality.

With this self-assurance, humankind has undertaken a mass manipulation of global ecosystems leading to the mass extinction of entire species of plants and animals, destruction of entire ecosystems; the disappearance of the Aral Sea, the bleaching of the great barrier reef, and the deforestation of the Amazon basin just to name three.

Settlement patterns, extraction of natural resources, pollution, demand for animal products, agriculture fertilizers and pesticides, changes in land use (habitat loss degradation and fragmentation), over-exploitation, disease, introduction of genetically modified plants, hunting, climate change, and invasive species, have all contributed to the alteration of the natural course of global ecosystems and global biodiversity.  

It is almost inconceivable how much human intervention has disrupted the delicate ecological balance evolved over millions of years; we have only just begun to realize the consequences of our impact.

According to a joint international report, the average abundance of native species in most land-based habitats has fallen by at least 20%, mostly since 1900. More than 40% of amphibian species, almost 33% of reef-forming corals and more than a third of all marine mammals, and an estimated 10% of insect species are now threatened.2 

Amongst the many unintentional consequences of human intervention is the transmission of foreign (alien) species transported across ecosystems contributing to significant ecological, economic and environmental damage. A subtle consequence of human intervention, and in part a natural consequence of interspecies interaction, invasive species transmission today presents yet another existential threat to our survival.

The transmission of invasive species has alerted the evolutionary pathway of native species through competitive exclusion, niche displacement, hybridization, introgression, predation, and ultimately extinction. Invasive species compete for resources, degrade habitat, introducing diseases costing the global economy billions of dollars every year.3

Although invasive species are only responsible for about 1%  of transported species that become established, and become pests, their impact is dramatic and costly.4 The World Conservation Union rates invasive alien species as the second-worst threat to biodiversity after habitat loss.5

The Commission for Environmental Cooperation notes that marine invasive species have dramatically altered some water bodies, changing sedimentation rates, oxygen and light levels, and impeding boating, fishing, and other recreational activities resulting in over $100 billion dollars worth of damage in economic losses across North America annually.6

Research on marine-based invasive species suggests that more than 80% of species were introduced unintentionally. The most common pathway being commercial shipping.

Liner shipping, perhaps more than any other mode of transportation, has made possible our global economy. Maritime shipping has connected countries, markets, businesses and people, allowing them to buy and sell goods on a scale not previously possible. The interconnectedness of global economies has depended largely on the liner shipping, perhaps the first truly global industry, over the past hundred years.  

In fact, shipping has been the catalyst for two of the largest mega geo-structures – the Panama and Suez canals. But maritime shipping has also been a significant contributor to the unintended transmission of species.

Shipping has enabled raw materials, component parts, finished products, and waste products to be exchanged globally, crisscrossing ecosystems with little or no surveillance of its impact on the integrity of those systems. There is however, a statistically significant correlation between shipping indicators (shipping cargo volume) and the number of harmful species reported, and the magnitude of shipping activities can predict the risk for harmful invasions.7

Studies indicate that of the identified invasive species, 39% are known to have been or are likely to have been transported by ship fouling, 31% by ship ballast, and 31% by either ship fouling or ballast.8 

To be certain, the shipping industry is not the only mechanism for the transmission of invasive species. Transport by tourists, concealed pest transmission through agricultural and animal exports, and mega projects like the construction of the Suez and Panama Canals have also contributed to the transmission of species across ecosystems.

The introduction and spread of alien species is further aggravated by climate change, the introduction of genetically engineered modifications, and increased susceptibility of altered or degraded ecosystems. The aquaculture industry is the next most common pathway for the transmission of harmful species.

The impacts of invasive species in Australia provides some of the most dramatic and well-known impacts of invasive species – the seasonal plagues of rabbits and mice, European carp, feral camels, feral pigs, and the blanketing of southern Australian agricultural landscapes by Paterson’s curse (Echium plantagineum).9  

Australia has experienced some of the broadest range of invasive alien species, both, due to intentional and unintentional introductions. In the 2001–2002 financial year (June to July), the combined estimated cost (economic losses and control) of invasive species was $9.8 billion, rising to $13.6 billion in the 2011–2012 financial year.10 

The threat to native species is so severe that in 2017 the Australian government unleashed a strain of a hemorrhagic disease virus into the wild to curb the growth of the continent’s rabbit population, responsible for destroying about $1150 million in crops every year.11 

In New Zealand, there are now as many alien established plant species as there are native species. By some estimates, invasive species have come to dominate 3% of the Earth’s ice-free surface over the last 500 years. 

It is estimated that adverse effects of invasive species on food security result in over $137 billion of losses in crop and forest production annually to the United States alone.12 The Invasive Species Centre estimates the cost of invasive species to Canada to be between $16.6 billion and $34.5 billion per year.13 

Vast land or waterscapes, in certain regions, are completely dominated by alien species, such as the star thistle Centaurea solstitialis in the rangelands of California, cheatgrass (Bromus tectorum) in the intermountain regions of the western United States, and water hyacinth (Eichornia crassipes) in many tropical lakes and rivers.14

Not all alien invasive species have been transmitted through negligence or unintentionally. There have also been some bizarre contributions to the introduction of invasive species.

On March 6, 1890, Eugene Schieffelin, a pharmaceutical manufacturer and a Shakespeare enthusiast with the American Acclimatization Society released 60 imported European starlings in Central Park, New York as part of their scheme to introduce every bird ever mentioned in Shakespeare’s plays to the United States.  With few predators, the starling proliferated and quickly spread across the continent from Alaska to Mexico. By 1927, they were established across Canada and are now, number 200 million, among the most common birds in North America.15

In another innocent intervention, Captain Walter Colquhoun Grant planted the seeds Scotch broom, a perennial shrub with bright yellow flowers of European origin in his garden in Sooke, British Columbia, in the 1850s. The plant was traded as an ornamental gardeners’ flower, used as packing material for transporting whiskey between California and British Columbia, and planted along highways to prevent soil erosion. It was only later determined that Scotch broom is toxic to humans and livestock if ingested, crowds out native plants, reduces open habitat for animals and insects, and its flammable high oil content makes it a fire risk.16

Similarly, a naturalist attempting to cross-breed European gipsy moths with American silkworms, to establish a silk industry in North America accidentally released the moths through an open window. An accident that has resulted in the annual defoliation of millions of trees. Similarly, Asian gipsy moths, introduced to Vancouver by Soviet freighters in 1991, continue to threaten Canadian forests.17

The threat today is however much more than a quaint challenge. The introduction of the lamprey eel, zebra mussel, and emerald ash borer have had a dramatic impact on marine and forest ecosystems across Canada.

The hemlock woolly adelgid (HWA) an invasive insect threatens the destruction of sensitive tracts of eastern hemlock trees. Easily spread by wind, animals and human activities, HWA feeds on the fluids of hemlock trees, causing death as early as four years from first establishment. From an ecological standpoint, eastern hemlock trees are a key component of sensitive natural environments, such as riparian habitats along streams and lakeshores.18

The emerald ash borer (Agrilus planipennis), a species of metallic wood-boring beetle native to East Asia, including China and the Russian Far East has resulted in a 99 percent mortality rate of its host trees responsible for destroying millions of ash trees across the country.19 No North American natural predators, insects or parasites have been able to slow the spread of the emerald ash borer or keep trees from being killed by it.20

Our most recent invasive species is the Giant Asian Hornet (Vespa mandarinia). Giant Asian hornets are carnivores that kill other insects for food and can cause serious damage to honeybee hives, a serious concern at a time when bee populations are already stressed. A colony of giant Asian hornets can kill up to 30,000 bees in a few hours. The destruction of bee populations can, in turn, have large impacts on the environment and food production industry because of the bee’s important role as pollinators. 

It is speculated that a female “Princess or Queen”, first seen in British Columbia could have been imported via outdoor terracotta/landscaping pots.21 

According to the Invasive Species Centre the cost of fighting the invasion of the Asian hornet – which basically consists of the cost of nest destruction- is estimated to cost approximately $44.6 million Canadian yearly.

In the aquatic environment, the economic impact of zebra mussels on industries, businesses and communities near the Great Lakes region was estimated to place the combined economic losses and direct costs associated with the 16 aquatic invasive species for which published information is available at $5.5 billion.22 

Another recent invader, the European green crab, with an appetite for commercially valuable clams and crabs, threatens important fisheries along Canadian coastal waters. 

Given the extent of the issue of invasive species there is a clear need for better quantification of both economic loss and expenditure across international jurisdictions, and for better coordination of strategies to mitigate and rehabilitate damage. While Canada has undertaken steps to mitigate damage from invasive alien species it may be time to refocus attention to a potentially volatile risk that threatens to do as much damage to the Canadian economy as we have experienced from the unexpected and unintended consequences of COVID-19.

According to the Fisheries and Oceans Canada website: “As a result of insufficient awareness of the nature and size of the threat, there have been limited levels of compliance with practices and regulations designed to minimize the damage.”23 Damage that is increasingly likely to be compounded by a changing global climate. 

Clearly, the impacts of invasions are felt locally, but the drivers of biological invasion are, to an increasing degree, global. However, there remains a paucity of information on invasive species at the global level. The Convention on Biological Diversity (CBD) has identified the need for “compilation and dissemination of information on alien species that threaten ecosystems, habitats, or species, to be used in the context of any prevention, introduction and mitigation activities”.24 

Canadians need a national strategy for the protection of our natural resources from the unintentional consequences of global engagement, a strategy with the same vigour that is dedicated to the crafting and protection of multinational trade agreements.

Nature Conservancy of Canada (NCC) biologist Dan Kraus notes that a crucial component for dealing with invasive species is creating awareness; even more important as climate change affects long-standing natural barriers.25 

Prioritizing corporate and legislative responsibility, and citizen action requires knowing which species are likely to be most harmful to native ecosystems, their identification, and distributions in order that a cohesive and coordinated response can be undertaken nationally to prevent, mitigate, or eradicate harmful invasive species.

“I think climate change means we really have to double down on our vigilance,” Kraus said. “So having an informed public out there so when they see something they can hopefully help identify and report it, so we can manage it quickly.”26

Responding to the challenge of harmful invasive species depends on public awareness and education for increased recognition of the need for strengthening policy frameworks, political commitment, and funding for a coordinated response.

As with so many public policy issues, public awareness and engagement is a catalyst for action. Our most precious resource is the natural beauty of our forests, waters, plains and mountains – the biodiversity that is Canada.  

As Benjamin Franklin famously advised, “An ounce of prevention is worth a pound of cure.” Clearly, preventing invasive species from arriving is better than the myriad costs attached to their potential damage to the Canadian economy and resources.

Perhaps it is time to re-examine our strategic plans for the protection of our ecosystems,  with a renewed recognition of the potentially cataclysmic consequences from unexpected and unintentional human intervention. 


Anil Anand is a Research Associate with the Frontier Centre for Public Policy. Anil served as a police officer for 29 years; during his career some of his assignments included divisional officer, undercover narcotics officer, and intelligence officer. He has worked in Professional Standards, Business Intelligence, Corporate Communications, the Ipperwash Inquiry (judicial public inquiry), and Interpol.




  1. Sodhi, Navjot S., Barry W. Brook, and Corey JA Bradshaw. “Causes and consequences of species extinctions.” The Princeton guide to ecology 1 (2009): 514-520. Accessed: May 18, 2020,
  2. United Nations. “Nature’s Dangerous Decline ‘Unprecedented’; Species Extinction Rates ‘Accelerating’” May 2019 Accessed: May 18, 2020,
  3. Mooney, Harold A., and Elsa E. Cleland. “The evolutionary impact of invasive species.” Proceedings of the National Academy of Sciences 98, no. 10 (2001): 5446-5451.
  4. Ibid.
  5. North American Invasive Species Network. Commission for Environmental Cooperation, Accessed: May 13, 2020,  The Commission for Environmental Cooperation was formed in 1994 jointly by Canada, Mexico and the United States for protecting North America’s environment as part of the North American Agreement on Environmental Cooperation (NAAEC).
  1. North American Invasive Species Network. Commission for Environmental Cooperation, Accessed: May 13, 2020, The Commission for Environmental Cooperation was formed in 1994 jointly by Canada, Mexico and the United States for protecting North America’s environment as part of the North American Agreement on Environmental Cooperation (NAAEC). Molnar, Jennifer L., Rebecca L. Gamboa, Carmen Revenga, and Mark D. Spalding. “Assessing the global threat of invasive species to marine biodiversity.” Front Ecol Environ 6, no. 9 (2008): 485-492.  
  1. Ibid.
  2. Department of Agriculture, Water and the Environment. Australian Government Accessed: May 21, 2020,
  3. Hoffmann, B. D., and L. M. Broadhurst. “The economic cost of managing invasive species in Australia. NeoBiota 31: 1–18.” (2016). Accessed: May 18, 2020,
  4. Biba, Erin. “Inside Australia’s War on Invasive Species” Scientific American.  Accessed: May 18, 2020,
  1. Paini, Dean R., Andy W. Sheppard, David C. Cook, Paul J. De Barro, Susan P. Worner, and Matthew B. Thomas. “Global threat to agriculture from invasive species.” Proceedings of the National Academy of Sciences 113, no. 27 (2016): 7575-7579.
  2. Invasive Species Centre. “Economic Impacts to Ontario” How do invasive species affect the economy? Executive summary excerpts from the updated 2019 economic impact report,  Accessed: May 13, 2020.
  3. Mooney, Harold A., and Elsa E. Cleland. “The evolutionary impact of invasive species.” Proceedings of the National Academy of Sciences 98, no. 10 (2001): 5446-5451.
  4. Ho, Wendy. “Tracing the roots of invasive species” nature Conservancy Canada, February 24, 2020, Accessed: May 18, 2020
  5. Simpson, Sarah. “It’s pretty, but broom has got to go” Cowichan Valley Citizen, May 28, 2018,
  6. Ho, Wendy. “Tracing the roots of invasive species” nature Conservancy Canada, February 24, 2020, Accessed: May 18, 2020
  7. Root, Julia. “Wrestling a wild and woolly pest”, Natural Resources Canada, June 15, 2018. Accessed: May 13, 2020
  8. Pietrobon, Brendan. “3 invasive insects that could wreck your backyard” CBC News, Jun 01, 2019, Accessed: May 13, 2020 
  9. Natural Resources Canada. “Emerald Ash Bore”, Govt. of Canada Accessed: May 13, 2020,
  10. Invasive Species Centre. “Giant Asian Hornet (Vespa mandarinia)” Accessed: May 18, 2020,
  11. Government of Canada: Fisheries and Oceans Canada. “A Canadian Action Plan to Address the Threat of Aquatic Invasive Species” May 4, 2018.  Accessed: May 18, 2020,
  12. Ibid.
  13. Molnar, J.L., Gamboa, R.L., Revenga, C. and Spalding, M.D., 2008. Assessing the global threat of invasive species to marine biodiversity. Front Ecol Environ, 6(9), pp.485-492.  Accessed: May 18, 2020
  14. Fitzpatrick, Ashley. “Climate change aids invasive species in Newfoundland”, The Telegraph, October 06, 2017 Accessed: May 20, 2020
  15. Ibid.