Surveying Invasive Species at Island Lake Conservation Area
This past July, we conducted our first invasive species bioblitz at Island Lake Conservation Area to identify invasive species present in the park. The two-day pilot had staff searching the park’s forests, lake and shoreline looking for invasive forest insects, plants and diseases and invasive aquatic plants, fish and invertebrates.
Here’s what we discovered.
During our land surveys, we observed and counted over 2,100 individual invasive plants. The plants cover 435,920 square metres of land area. That’s equivalent to the area of 276 hockey rinks!
The top three most observed invasive plants were:
- European buckthorn (Rhamnus cathartica) – 772 observations
- Invasive honeysuckles (Lonicera spp.) – 415 observations
- Glossy buckthorn (Frangula alnus) – 353 observations
European buckthorn was the most pervasive invasive plant at the park. Crews counted an estimated 37,250 individual stems of buckthorn. We also found four invasive plants that are unfortunately available at many garden centers and nurseries in Ontario.
- Chinese silvergrass (Miscanthus sinensis)
- Japanese-spurge (Pachysandra terminalis)
- Yellow iris (Iris pseudacorus)
- Chinese wisteria (Wisteria sinensis)
There is currently no legislation against selling invasive species unless they are listed under the Invasive Species Act. You can help stop the spread of invasive species by choosing native plants for your gardens using our guide to invasive plant alternatives.
Japanese knotweed (Reynoutria japonica) is listed as restricted under the Invasive Species Act, which means it cannot be sold or moved. Crews found it in two areas covering a total of 32 square metres. We’ve been prioritizing Japanese knotweed removal at our conservation areas over the past decade. The patches found at Island Lake will be added to the list for future removal work.
Crews also looked for forest pests and were pleased to not find any new invasive insects or signs of dying hemlock trees, as a result of hemlock wooly adelgid (Adelges tsugae). It’s spreading in Ontario but we have not yet observed it in Credit River Watershed. This invasive insect slowly kills eastern hemlock trees by feeding on the tree’s sap. Thankfully it was not observed at Island Lake.
Invasive forest insects found at Island Lake include:
- Japanese beetle (Popillia japonica)
- European praying mantis (Mantis religiosa)
- Emerald ash borer (Agrilus planipennis)
- Beech bark disease (Cryptococcus fagisuga and Neonectria faginata)
In the Water
Crews used a number of techniques to look for invasive fish, minnows, mussels and snails in the over 121 hectares of water at Island Lake. This included seine nets at 19 sites, minnow traps at 17 sites and sediment collections at 37 sites. Only one aquatic invasive species was found in abundance: banded mystery snails (Viviparus georgianus).
Crews also looked for plants growing in the lake and along the shoreline. We found three invasive plants:
- Curly-leaved pondweed (Potamogeton crispus)
- Eurasian water-milfoil (Myriophyllum spicatum)
- Phragmites (Phragmites australis australis)
The first invasive species bioblitz at Island Lake was a success. Staff sharpened and shared their identification skills and tested new sampling methods. Over the course of two days, priority areas throughout the park were surveyed. As results continue to come in, we will be adding them to our dataset. Using what we learned during this pilot, we will adjust our data collection protocols and apply them at future invasive bioblitzes.