Freshwater Pond and Lake (FW) Ecosystems
In the Discovery Islands
• Freshwater (FW) pond and lake ecosystems are open water bodies with water depths greater than 2 metres and little to no floating vegetation. The difference between a pond and a lake is size: ponds are smaller than 50 hectares, and lakes are bigger than 50 hectares.
• Freshwater ponds and lakes are influenced by groundwater, precipitation, stream flow and evaporation.
• They often form complex inter-relationships with the linear riparian ecosystems along their shorelines, as well as with wetland ecosystems that are nearby.
Open freshwater ecosystems include both ponds and lakes. A pond or lake ecosystem consists of four distinct habitats: shore, surface film, open water, and bottom water. Each provides conditions that support different kinds of organisms with specific adaptations. There is considerable variability in the available habitats. For example, bottom water conditions are variable as they are greatly influenced by substrate and depth. Shallow sandy bottoms provide a nesting environment for earthworms, snails, and insects, while the more muddy conditions of deep bottom water supports flatworms, rat-tailed maggots, and dragonfly nymphs. All open freshwater ecosystems provide critical breeding habitat for invertebrates, amphibians, and fish. These water bodies are also valuable habitat for many resident birds and also a stopover for migrating species. They are a rich source of nutrients for many aquatic and terrestrial species—and a vital source of drinking water for all!
In the Discovery Islands, Beavers are often the cause of ponds. The iconic rodents are famous for building dams by felling trees with their strong teeth; and their lodges—partially submerged structures of branches and mud—can change fields and forests into the watery habitat in which they and many other species thrive.
Ponds and lakes are found throughout the Discovery Islands in various terrains and at all elevations. For humans, the island lakes are popular destinations that offer opportunities for healthy recreation.
WHEN YOU EXPLORE Ponds and Lakes, be careful not to disturb vegetation at the water’s edge – particularly between March and August, when birds are likely to be nesting there.
Look For Typical & Rare Species in Freshwater Pond and Lake Ecosystems
FAUNA Beaver, blue-eyed darner dragonfly, fish species (salmonids, stickleback, coastal cutthroat trout), common merganser, eight-spotted skimmer, northern red-legged frog, rough-skinned newt, river otter, western toad
FLORA Buckbean, cattail, clasping-leaved pondweed, common mare’s tail, floating-leaved pondweed, greater bladderwort, hard-stemmed bulrush (tule), narrow-leaved bur-reed, Sitka sedge, water lobelia, watershield, yellow pond-lily.
SPECIES AT RISK Two-edged water-starwort (Blue), water bur-weed (Blue), waterwort water-milfoil (Blue), painted turtle (Red, Endangered), western toad (Blue, Special Concern), northern red-legged frog (Blue, Special Concern)
No ecosystems at risk for freshwater
*For comprehensive species lists & rarity explanation, click here.
Some Local Pond and Lake Ecosystems
Lakes and ponds are found in various terrains and elevations throughout the Discovery Islands. Quadra, West Redonda and Sonora have several large Freshwater ecosystems, while some of the other large islands, except East Redonda have a few.
Familiar Locations: Sonora Island: Florence Lake, Cortes Island: Hague Lake, Quadra Island: Morte Lake, Read Island: Rosen Lake, Maurelle Island: Caroline Lake, West Redonda: Black Lake, Stuart Island: Eagle Lake