7 Questions with David Mazerolle

Gulf of St. Lawrence Aster (Symphyotrichumlaurentianum) — *_{Gulf of St. Lawrence Aster (Symphyotrichum laurentianum)}*

New Brunswick is home to many species at risk including several at risk coastal plants. One of these plants is the Gulf of St. Lawrence Aster (Symphyotrichumlaurentianum). This plant is only found in the southern part of the Gulf of St. Lawrence. At present, the species is currently listed as threatened by COSEWIC, due to significant declines in population size.

David Mazerolle is an Ecosystem Scientist with Parks Canada and also a member of the NB Botany Club. We asked him a few questions about the Gulf of St. Lawrence Aster and about his experience working with plants. Here is what David had to say:

1. What is the Gulf of St Lawrence Aster?

The Gulf of St. Lawrence Aster is a small annual plant species with thin fleshy leaves. It’s part of the Aster family, which includes lots of common and well known species including daisies, sunflowers, goldenrods, thistles and dandelions. Like other plants in this family, Gulf of St. Lawrence Aster produces flowers that are grouped in “heads” which appear to be a single flower but are in fact a densely grouped cluster of tiny flowers. In Gulf of St. Lawrence Aster, these heads look a bit like little leafy buttons and don’t bear anything that looks like a petal. In contrast with many other plants in the Aster family, the Gulf of St. Lawrence Aster isn’t very showy. It can reach sizes of over 20 cm, but the average height of all plants in a patch will often be under 5 cm. Overall, it’s a species that is easy to miss unless you know exactly what to look for.

2. What is unique about the Gulf of St Lawrence Aster?

This species is endemic to the southern Gulf of St. Lawrence (i.e. it’s only found in this region and nowhere else in the world). It is only known to occur at a handful of sites in the Magdalen Islands, on the north shore of PEI and along the eastern shore of NB. The Gulf of St. Lawrence Aster is one of very few plants to have evolved in this region about 10,000 years ago around the time the glaciers were receding and vegetation was gradually reclaiming a barren landscape. Throughout its range, it often shares its habitats with several other provincially rare and sensitive species.

3. Where does the Gulf of St Lawrence Aster grow?

It grows in coastal wetlands, most often along the shores of what are regionally called “barachois ponds”. These barachois ponds consist of lagoons that are partially or completely sheltered from the ocean by a dune. The Gulf of St. Lawrence Aster can tolerate some exposure to salt but can’t grow in conditions as salty as seawater. It is usually found in areas where salinity is lowered slightly by inflowing freshwater (e.g. brooks) or precipitation. It doesn’t compete very well with other vegetation and usually grows in sandy or muddy areas that have been cleared by various coastal processes such as flooding, erosion, wave disturbance and ice scouring. I often refer to it as a “Goldielocks” species – it needs coastal disturbances like storms and flooding to create and maintain its habitat, but when these disturbances are too severe its habitat is often lost completely. Essentially, the species is only found where a very specific set of conditions are met – tidal shores and marshes where conditions aren’t too salty, in areas moderately affected by coastal storms. In the end, this specialization makes the Gulf of St. Lawrence Aster very sensitive to changes in coastal ecosystems.

4. What role does the Gulf of St Lawrence Aster play in the environment? Why should people care about the Gulf of St Lawrence Aster?

These are tricky questions that commonly come up when we talk about species at risk, particularly when dealing with very rare ones. People often hope for a clear and easy answer to these questions, something including a key ecological role that maintains ecosystems and allows other species to thrive. Unfortunately, many of our most threatened species are poorly understood. It’s harder to study species that are extremely rare, and as a result their relations with other species and their environment aren’t well known. Saddest of all, we sometimes only come to understand the ecological role of a given species once that species is gone and we start noticing other changes brought on as a consequence of its disappearance. Ultimately, the importance of Gulf of St. Lawrence Aster comes down to a philosophical belief that is at the heart of biodiversity conservation: every species has an intrinsic importance and a right to survive. The Gulf of St. Lawrence Aster’s precarious status doesn’t necessarily make it more special than any other species, but it does underline the fact that it truly needs our care and attention in order to survive.

5. What is the conservation status of the species? Why has it been labelled as such?

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) designated the species as being of Special Concern in 1989. The committee then reassessed the species in 2004, designating it as Threatened. In 2005, the species was also added to the federal Species at Risk Act with a legal status of Threatened. The Gulf of St. Lawrence Aster is considered to be a species at risk because it only occupies a very small total area, its abundance can fluctuate widely from year to year, and several population sites have been lost due to severe coastal storms and development. Furthermore, climate change, sea-level rise and invasive plant species also represent existing and potentially increasing threats.

6. Is there anything currently being done to help the Gulf of St Lawrence Aster?

Several different groups and individuals have been active in surveying suitable habitat throughout the range of Gulf of St. Lawrence Aster in the hopes of gaining a better understanding of its distribution and in hopes of finding new populations. These include the Atlantic Canada Conservation Data Centre, Parks Canada, Nature NB and Attention FragÎles, to name a few. These groups, along with various researchers, have worked hard to monitor the state of known populations over time. Various researchers have also studied the species’ growth requirements and ecology. Kouchibouguac National Park and Prince Edward Island National Park are both presently working to actively reintroduce the species to historical sites and translocate it to new areas. These efforts are in collaboration with the University of Prince Edward Island, where the species is cultivated in greenhouses. Seeds produced through cultivation at UPEI are placed in the care of Parks Canada staff, who introduce them to suitable habitat sites. To date, these efforts have proved to be moderately successful at establishing occurrences of the species, although the creation of self-sustaining populations requires repeated introduction of seeds and depends on natural ecological processes that can’t be controlled. If habitat is no longer suitable, no amount of seeding will bring the species back to a site.

7. What motivated you to focus on plants?

When I was just beginning as a field biologist, I first started out working on songbirds, but quickly gravitated to plants. It struck me that plants are the foundation of life and the base of almost all food webs on earth, yet many of us don’t really give them much thought. I gradually picked up knowledge and experience through working various jobs as a field botanist and eventually made a career out of it. I’ve always been driven by curiosity and a love of learning, and working with plants is great for someone like me. Our flora is wonderfully diverse; there’s a lifetime of discovery waiting for anyone willing to take a closer look at the plants that surround us.