It’s time to highlight another of PEI’s important habitats! Today let’s look at our natural ponds.
I say “natural” because the Island has hundreds of human-made ponds but far fewer natural bodies of freshwater. While our constructed sites are often historically interesting - many hosted working mills in the 1800s and 1900s - the Island’s natural ponds are more biologically diverse and home to some provincially rare species.
We should also clear up some terminology. The Island’s settlers were fairly loose with the term “lake” as a place name. We have a dozen named lakes, but few of them truly are. Some, such as South Lake, are really barachois: an area of open water behind a sand dune or spit. Most are ponds. Although the two words are often used interchangeably, a lake is deep enough that sunlight doesn’t reach all the way to the bottom. Portage Lake is a good (and well-named) example, so deep that it’s rumoured to be bottomless.
Virtually every Island wildlife species will use a pond at some point in its life. Invertebrates, fish, amphibians, reptiles, birds and mammals can all be found in and around ponds, but I think it’s the plants that make them most interesting. Most ponds hove a gradation in water levels, from dry at the edges, to a seasonally flooded area, then on to shallow water, and deeper open water. That shallow water area - called the littoral zone - is tremendously productive and important to plants, animals and the overall health of the pond.
O’Keefe’s Lake (Photo 1) is one of our spring and rainwater-fed ponds with no stream leading into it. It would have formed at the end of the last ice age some 12,500 years ago, in a depression scoured out by glaciers.
Its well-developed littoral zone is home to vascular plants that live entirely under water (such as Quillwort, Isoetes lacustris, not shown), those that float on the surface (like Variegated Pond Lily, Nuphar variegata, Photo 2), and those that poke their heads above the water (including White Buttons, Eriocaulon aquaticum, Photo 3 and Water Lobelia, Lobelia dortmanna, Photo 4).
In addition to these few examples, our natural ponds are home to hundreds of native plants including grasses (Poaceae), sedges (Cyperaceae), and rushes (Juncaceae), as well as bur-reeds (Sparganium spp,), milfoils (Myriophyllum spp.), pondweeds (Potamogeton spp.) and many others.
The Island’s natural ponds aren’t numerous, but they are among our most diverse and important habitats. That makes them a cool PEI landscape!