Salt Marshes Part 1: Ecology
PEI salt marshes are so environmentally and culturally important that I’ve divided my info into three posts. Today we have an introduction to salt marshes generally; in Part 2 we’ll explore the historical importance of ‘marsh hay’, and Part 3 will look at some well-adapted (and edible!) salt marsh plants .
To many people, a healthy habitat is one that has lots of different species. More species is better, right? Not always! Salt marshes are critically important habitats that are low in plant diversity but very high in productivity.
Salt marshes form where our freshwater streams and rivers meet saltwater at the coast. The most extensive areas - as much as 700 hectares (1,730 acres) in some places - can be found along the Island’s more-sheltered south shore and inside the protected bays and estuaries of our north shore. The beautiful salt marshes of the Percival River in Prince County (Photo 1) are excellent examples.
‘Productivity’ is a measure of how much living material plants make from sunlight. Salt marshes are among the most productive habitats on earth, far more so than forests. As a result, these areas are some of our most important carbon sinks. They also provide many other essential services such as water purification, protecting coastlines from storms and flooding, providing nursery areas for fin- and shell-fish, and serving as breeding and feeding areas for waterfowl and shorebirds.
PEI’s salt marshes would not exist without a trio of Cordgrasses (Photo 2). The driest, upper reaches of the marsh are usually dominated by Rough Cordgrass (Spartina pectinata, Photo 2 left). Saltmeadow Cordgrass (Spartina patens, Photo 2 centre) claims the next zone, an area above mean high tide but flooded during the full moon and storm tides. Smooth Cordgrass (Spartina alterniflora, Photo 2 right) thrives in the lowest zone, and is able to withstand being alternately flooded by salt water and exposed twice daily. These grasses - collectively known as ‘marsh hay’ - were highly valued by the Island’s early settlers. More on that in my next post.
While I could easily find hundreds of plant species in a PEI forest, a typical salt marsh would host just a few dozen. In addition to Seaside Plantain (aka Goose Tongue, Plantago maritima, July 28) and Sweetgrass (Anthoxanthum nitens, May 30), typical examples include Sea Lavendar (Limonium carolinianum, Photo 3) and various edible succulents (that I’ll highlight in Part 3).
Salt marshes also host aquatic mammals such as Mink and Muskrat, as well as terrestrial species including Eastern Coyote, Red Fox and Raccoon. Photo 4 is evidence () from a Raccoon hanging out in the salt marsh and feasting on Blue Mussels - shells and all!
It’s estimated that Atlantic Canada has lost two-thirds of its salt marshes over the past 200 years; conservation of our remaining areas is important. I encourage you to take some time to appreciate this cool and important PEI landscape .