Invasive Species

MTRI Guide to Invasive Species

I consider a guide produced by MTRI in 2012 as the most authoritative source of info on invasive species in Nova Scotia currently. (They use the term “alien” instead of “exotic”.)

The MTRI Guide  lists the following as invasive plant species:

  • Norway maple (Acer platanoides)
  • Oriental bittersweet (Celastrus orbiculatus)
  • Glossy buckthorn (Frangula alnus)
  • Common reed (Phragmites australis ssp. australis)
  • Scots pine (Pinus sylvestris)
  • Rugosa rose (Rosa rugosa)
  • Yellow floating heart (Nymphoides peltata)- an aquatic

and lists these as species to watch out for:

  • Purple loosestrife (Lythrum salicaria)
  • Knotweed Species (Polygonum cuspidatum & sachalinense)
  • Multiflora rose (Rosa multiflora)
  • Giant hogweed (Heracleum mantegazzianum)
  • Common valerian (Valeriana officinalis)
  • Common hawkweed (Hieracium lachenalii)
  • Woodland angelica (Angelica sylvestris)
  • Garlic mustard (Alliaria petiolata)
  • Reed canary grass (Phalaris arundinacea)

Of those, all are currently present in NS except Woodland Angelica (it is in NB)

The guide gives detailed descriptions of the species, their habitats etc. It also includes fish (chain pickerel and smallmouth bass), Dutch Elm Disease, Balsam Wooly Adelgid. Smallmouth bass occurs in Sandy Lake.

I suspect if they were revising the guide today, Rosa multiflora would be on the first list, not the second.


Nova Scotia Invasive Species Council
Attempts to integrate monitoring of and provide info about invasive species in NS under have come and gone, some groups paying the role for a period by default. The Nova Scotia Invasive Species Council was launched in 2020. Hopefully it will be around for a while. View the About Us page for more about the Council, it goals etc.


A perspective on iNvasive species, Daniel Simberloff
CBC podcast, ~16.00 on Canada’s wild pig populations are on the rise. How big of a problem is this? Good discussion wit Simberloff on invasives generally (He is authors of Invasive Species: What Everyone Needs to Know.

Invasive Species on Municipal Radar
HRM Document, 2010 but still useful, informative. 30 pages


Also: Species at Risk in Nova Scotia #6 – Fresh Water species
CBC Information Morning “Of all the creatures we’ve discussed in our species at risk series, none may be more vulnerable than the Atlantic Whitefish. Today we’re looking at that critically endangered species.” View also: Wild Atlantic whitefish struggle to survive in Nova Scotia CBC Post). The article talks about chain pickerel and Chinese mystery snail as serious aquatic invasive species in Nova Scotia.

On Chinese mystery snail:

Chinese mystery snail (from Wikipedia)

“[SMU Prof Linda] Campbell said Chinese mystery snails eat algae and can change the nutrient cycle of the lake. “They’re introduced through aquarium trades. A lot of people buy them as pets in the pet store. They don’t want these aquariums anymore so they release what’s left back into the lakes…The aquarium trade is one of the top sources of invasive species in our ecosystems across Canada…Campbell said Chinese mystery snails are reducing the amount of food for other fish. We’re finding them in more and more lakes than we realized. They might be more widespread than we really think”.

On Chain Pickerel:

‘Chain pickerel are non-native to our province. They are veracious predators, so they attack anything that moves from what our experience has been,” Brooke Noddin, the foundation’s executive director, told CBC Radio’s Information Morning on Tuesday. “They not only out-compete and directly predate on native fish species, they also predate on small mammals, amphibians, reptiles — anything that moves.” Noddin said chain pickerel have been known to clean out watersheds quickly.

She said the foundation, which has been conducting content analysis of both smallmouth bass and chain pickerel for four years, once found two baby snapping turtles inside the stomach of a chain pickerel.
“They were still alive and we were actually able to reintroduce them back into the water. A small success story on our part,” Noddin said.

Campbell said freshwater mussels are really important to lakes because they help filter the water, change nutrients in the lake and are also a source of food for many fish species.

“They are fundamental for many lakes across Eastern Canada, but unfortunately the numbers of many of those species are really going down,” she said.