The Nova Scotia Plants publication was just launched in October 2014. It had been 16 years since a comprehensive flora for the province was published. During those 16 years, at least 40 plants were added to the total. Are these newcomers? The answer is no, and yes! Botanists are steadily finding new relationships between and amongst genera. Sometimes this means a lumping of species or varieties and sometimes it means a splitting of species. These plants have always been present; their relationships have changed. Then there are the plant species who are upwardly mobile. These are the plants who are expanding their range, usually from south to north.
Sometimes they are hitchhikers, such as Garlic Mustard, which marched into the province. As it is invasive along roadsides in eastern North America, it was only a short while before it appeared in our province, possibly by tires of vehicles carrying the seeds. During the 1700-1900s most of the introduced plants arrived on our shores, literally, via ships’ ballast. The weight of soil and rocks gathered from European shores ensured that Nova Scotia, received seeds of European species, especially the fast-growing weedy ones. With the advent of rail, came species from the western prairies and the mountains, such as lupines and mustards. These are opportunists, spreading as far and wide as the trains that carried them.
The intentional introductions are plants that arrive here as crops, ornamentals or as reminders of far-flung travel. And sometimes, the plants are introduced by people, who just don’t consider the environmental impacts. During the Christmas holidays, I received a series of emails from concerned naturalists about a species of aquatic plant observed in a local pond in Halifax. Some of our most vulnerable habitats to plant invasion are streams, lakes and ponds. Aquatic species are very difficult to control. This plant, the Carolina Fanwort, Cabomba caroliniana is popularly used in aquaria. Native to the southeastern part of the US, it is now resident in Halifax County. It arrived at Frog Pond when someone emptied their unwanted aquarium plants into the pond, an unacceptable practice on several levels. Its effects on the native vegetation remains to be seen. We don’t know if it will survive the winter. It is now listed officially as invasive in ME, MA, VT and CT, although it is native and even extirpated in some of the more southerly states. What we do know is that its presence probably indicates a decline in water quality. It is difficult for non-native species to invade healthy ecosystems.
Posts
No comments:
Post a Comment