The state of Canada’s biosecurity efforts to protect biodiversity from species invasions

Zebra and quagga mussels are proficient filter feeders native to the Black Sea region (Son 2007). Both species are able to spread throughout lakes and river systems, encrusting hard surfaces and substrate (e.g., rocks, endemic mollusc shells, human infrastructure; Karatayev et al. 2011) with high resulting annual management costs (Meyerson and Reaser 2003). Zebra and quagga mussels were introduced to the Laurentian Great Lakes through ballast water released by ships originating from areas with native or introduced populations. Zebra mussels were first recorded in the American portion of Lake Erie in 1986 (Carlton 2008) and have since established in the Canadian portion of the lake through a combination of natural spread and unintentional human aid (e.g., hull fouling; Brown and Stepien 2010). In abundance, zebra mussels can induce changes in substrate via accumulations of copious shell fragments, rapidly increasing water clarity by filtering plankton and small debris, and subsequent cascading impacts on food webs, nutrient cycling, and community assemblages (Karatayev et al. 2002). Negative impacts on fish communities are likely as small reductions in fitness or reproductive success compound over time. For instance, zebra and quagga mussels may worsen the diet quality of species such as lake whitefish (Coregonus clupeaformis; McNickle et al. 2006) or the number of viable deposited eggs in at-risk fishes such as lake trout (Salvelinus namaycush; Marsden and Chotkowski 2001).

At the time of their introduction to Canada, there were no safeguards in place to anticipate and prevent the establishment of zebra and quagga mussels. In 1989, the federal government began implementing large-scale (i.e., nonlocal) ballast water management programs to manage various aquatic IAS; however, compulsory regulations were not introduced and enforced until 2006 (see Scriven et al. 2015 for a detailed timeline of Canadian ballast water regulation). Since these preventative measures were made compulsory, no IAS appear to have established in the Great Lakes via ballast water, although introductions have occurred in Canada’s less well-regulated marine systems (Scriven et al. 2015).

Asian long-horned beetles (ALB; Anoplophora glabripennis) are native to China and Korea but have been unintentionally transported outside their native range by international trade, primarily via their contamination of wood packing material (Hu et al. 2009). ALB larvae damage trees primarily through larval tunnelling, which compromises tree vascular tissues and structural integrity, eventually leading to tree mortality (Hu et al. 2009). ALB were first found in North America in 1996, when a population had become established in the US (Haack et al. 2010). They have since become established on two separate occasions in Canada (NRCan 2020). The ALB introduced to Canada near Toronto in 2003, and incomplete eradication efforts resulted in a small population that remained undetected in the area until 2013 (Turgeon et al. 2015), whereafter it was eradicated (NRCan 2020). A third introduction to Canada was reported in Edmonton in 2019, but a population is not thought to have established (CFIA 2019c). ALB prefer maples (Acer spp.) as host trees but will colonise other common hardwood trees (NRCan 2020). ALB invasions in Canada could lead to devastating biodiversity losses, which may affect the livelihoods of all peoples living in Canada, including Indigenous communities, and cause billions of dollars in damages to Canadian industries including forestry, maple syrup, and tourism (NRCan 2020). Under the Plant Protection Act introduced in 1990 (Table 1), the federal government has maintained the power to carry out inspections on shipping containers and other cargo in search of pest species (including potential IAS). However, the brief establishment of ALB in Canada (as well as the 2013 re-emergence) appears to have been noticed first by community members rather than caught through government efforts (CTV News 2019; Taylor 2021), although CFIA inspections did reportedly prevent another introduction in 2020 (Taylor 2021). Thus, while historical “success” in ALB prevention may be attributed more to sheer chance and astute citizens, the federal infrastructure that can coordinate successful prevention efforts has long been in place (even if enforcement could be more rigorous).

Spotted lanternflies (SLF; Lycorma delicatula)—a species of planthopper (Fulgoromorpha)—are native to parts of the east and southeast Asian mainland. SLF had established invasive populations in Korea and Japan, as well as the US, by no later than 2014 (Leach and Leach 2020). SLF’s preferred host is the invasive tree-of-heaven (Ailanthus altissima; Barringer et al. 2015). SLF are not known to have become established in Canada yet; however, tree-of-heaven can be found in eastern Canada (Dara et al. 2015). SLF larvae feed on numerous cultivated plants, including grape vines and fruit trees, and many common trees native to Canada (e.g., red maple (Acer rubrum), American beech (Fagus grandifolia); Avanesyan and Lamp 2020; Dara et al. 2015). The build-up of honeydew (liquid secretions) from SLF feeding on host trees promotes sooty mould (Ascomycota spp.) growth and other detrimental consequences beyond direct damage from feeding (Dara et al. 2015). Since tree-of-heaven has an extensive distribution in the US, SLF could establish in Canada via spread from areas bordering Canada containing tree-of-heaven populations (Rowe et al. 2020), particularly in the empirically derived high-suitability areas in southern Alberta and Saskatchewan, Ontario, Quebec, and the Maritime provinces (Wakie et al. 2020). Southern Ontario contains the most suitable habitat for SLF and is also closest to existing invasive populations in the US (Wakie et al. 2020). While SLF is likely to have negative consequences on biodiversity, agriculture (e.g., vineyards), and forestry, knowledge on the likely impacts in Canada remains largely theoretical (Urban 2020). Canada does not appear to be well-prepared for preventing SLF cross-border establishment or other outbreaks and may become particularly vulnerable, as climate change promotes the northward expansion of more suitable environmental conditions from the US. The invasion pathways of SLF have not been rigorously identified; however, both adults and deposited egg masses may be transported on wood or nonplant surfaces such as vehicles (Dara et al. 2015), making transport contamination pathways likely. The federal government is aware of this species as a likely looming threat (CFIA 2019c); however, no clear active monitoring plans are currently in place.

Asian carp is a blanket term referring to four cyprinid fishes: grass carp (Ctenopharyngodon idella), silver carp (Hypophthalmichthys molitrix), black carp (Mylopharyngodon piceus), and bighead carp (Hypophthalmichthys nobilis) (George et al. 2017). Asian carp were first introduced to North America in 1963, with numerous subsequent introductions of each species for aquaculture and biological control/habitat manipulation (Kelly et al. 2011). Escape or intentional release of these large fish can quickly lead to established populations in natural ecosystems. The Canadian government has long been aware of the threat of Asian carp, as certain species have propagated up the Mississippi River Basin towards the Laurentian Great Lakes (e.g., Mandrak and Cudmore-Vokey 2004). Asian carp can access Lake Michigan from the Chicago Area Waterway System, an artificial corridor between the Mississippi River and Laurentian Great Lakes watersheds (Wittmann et al. 2014). Grass carp currently pose the largest threat to Canada as spawning has been observed in the Sandusky River, a tributary of Lake Erie (Embke et al. 2016). Ivan et al. (2020) predicted that established Asian carp populations could lead to major changes in ecosystem structure and function in the Great Lakes. Empirical evidence indicates that Asian carp invasions can negatively impact the biomass of planktivorous fishes such as gizzard shad (Dorosoma cepedianum) (Phelps et al. 2017), aquatic vegetation, and species that rely on pre-existing cover (Cudmore et al. 2017). In addition, silver carp are known to jump as high as 3 m out of the water when disturbed by boat activity and other sounds (Vetter et al. 2017), leading to high-velocity fish–human collisions. Subsequent introductions or dispersal through connected waterbodies can lead to further exploitation of inland Canadian waters, many of which south of 60 °N (i.e., southern borders of the Territories) are conducive to the survival and establishment of Asian carp (Cudmore et al. 2017). Restrictions on fish movement, aquaculture, and sale are in place in both Canada (Ontario and Quebec) and the US (Cudmore et al. 2017). To date, none of the species are confirmed to be established (reproducing), but 28 grass carp have been captured in Canadian zones of the Great Lakes (primarily Lakes Erie and Huron; DFO 2019), and three bighead carp were captured in western Lake Erie in the early 2000s (DFO 2020). Community monitoring is also being employed, where sightings can be reported over email or telephone (dfo-mpo.gc.ca/contact/invasive-species-especes-envahissantes-eng.html). Further monitoring technologies (e.g., eDNA detection; Guan et al. 2019) are being developed for more stringent future monitoring. The effectiveness of future efforts relies on continued cooperation and partnerships with the US, who have been investing in domestic spread mitigation technologies (e.g., dispersal barriers) that can contribute to establishment prevention in Canada (Cudmore et al. 2017).

IAS in Canada have been leading causes in biodiversity loss. For example, the sea lamprey contributed greatly to population crashes in Great Lakes lake trout populations (Coble et al. 1990) and the extinctions of longjaw and deepwater ciscoes (C. alpenae and C. johannae, respectively; Miller et al. 1989). IAS must be addressed to meet aims of preserving biodiversity in line with both international (e.g., CBD) and domestic (e.g., the Species at Risk Act, which contains no mention of IAS) agreements and initiatives. The Canadian federal government appears to be most willing to respond to IAS that pose substantial economic risks towards major industries, rather than those that pose risks to biodiversity and other, less direct economic impacts. While agriculture, forestry, and fisheries represent a substantial portion of the economy, Canada also possesses unique and biodiverse landscapes that hold significant cultural value, ecosystem services, and benefits to other economic sectors (e.g., tourism). Much of the country’s natural ecosystems remain intact or nonindustrialised, so a tendency to give disproportionately more attention to lands and waters associated with direct industrial benefits is unsustainable and incompatible with Canada’s biodiversity targets under the CBD.

Canada’s Natural Sciences and Engineering Research Council (NSERC) recently committed to creating a centralised repository of biodiversity monitoring data (Canadian Biodiversity Observation Network). The centralisation and sharing of countrywide biodiversity data will help overcome the data limitations surrounding Canadian IAS surveillance and risk modelling compared with the US. We commend this initiative and believe that the collection of IAS-relevant data will be central to the success of this framework.

Effective biosecurity requires leadership and coordination. Having centralised government agencies (or a unit within an agency) that direct biosecurity-relevant guidelines and initiatives appears to be highly effective in Australia and New Zealand. Implementing a central authority to lead and oversee biosecurity efforts could benefit Canada greatly. This authority would ideally be tasked with identifying Canada’s biosecurity priorities, as well as coordinating the roles of agencies at multiple levels of government in IAS research and management. A consolidated federal authority could boost the efficacy of provincial or territorial efforts by laying the groundwork for consistent, standardised courses of action for different IAS management scenarios. Furthermore, this strategy could facilitate communications with other government agencies concerned with relevant interests and activities (e.g., climate change, economics, parks and land use, etc.). We are not necessarily advocating for an entirely new government department, but perhaps a unit not unlike the Canadian Wildlife Service that operates within Environment and Climate Change Canada. We note the easier implementation of centralised federal measures in the US due to the Supremacy clause of the US Constitution, but we believe the Canadian federal government could ensure provincial biosecurity policies are written into federal law and enforced (unlike the provincial provisions in the Species At Risk Act).

Canada’s biosecurity policies should be flexible and anticipate future changes (Table 4). Human population increase and climate change will likely create new biosecurity threats and exacerbate existing ones. It is imperative that Canada maintains flexible policies that are regularly reviewed and adapted to incorporate new information. Future research on IAS must compensate for taxonomic and geographic biases in the availability of current knowledge and social perceptions of IAS (Pyšek et al. 2008; Kapitza et al. 2019). More efficient data-sharing platforms and alert systems can be used to accelerate communication of novel biosecurity-related findings. New technologies and IAS treatment techniques should be proactively developed and embraced. Some recently developed technologies include instruments to detect wood-boring insects, recycled plastic pallets as an alternative to wooden pallets, hull fouling resistant paints, and eDNA use for early detection of aquatic IAS (Jerde et al. 2013; Guan et al. 2019). Efforts should also be made to ensure that anthropogenic migration corridors (e.g., from climate change related assisted mitigation initiatives) do not inadvertently contribute to the spread of IAS (St-Laurent et al. 2018). Return on investment models can be used to demonstrate the value of forward-thinking when preparing for future biosecurity threats (Leung et al. 2014).

As Canada updates its biosecurity policy to meet future conditions, it is important to recognize that some changes could cause tensions (Crowley et al. 2017). Conflict should be anticipated and mitigated to prevent disagreements from damaging relationships and IAS management outcomes. Implementation of new policies should be handled with transparency and coupled with public education campaigns such as signage, advertisements, and school community science programs. Neglecting to educate the public about the value of an initiative can ultimately result in its failure, regardless of its validity, as well as inhibit their engagement in community science. Additionally, policy makers should be aware of conflicting perspectives regarding eradication of some IAS among Indigenous Peoples (Bhattacharyya and Larson 2014) and should therefore prioritize bilateral communication to achieve positive outcomes for all parties. Scientists and policy makers must recognize that without the support of stakeholders, rightsholders, Indigenous Peoples, and the general public, implementation of biosecurity protocols is unlikely to be successful.