In today’s post, the park’s former chief naturalist, Angela Gunn, reflects on the at-risk pitcher thistle.
It’s been almost 20 years since we took a close look at the pitcher thistle (cherry jug) and we added it to our provincial list of species at risk.
With a height of up to one meter, the pitcher thistle projects its slender silver profile against the background of dunes and coasts.
It humbly asks for its own space to grow in unstable, nutrient-poor sands.
What does this plant offer me?
What will the world lose if this species does not persist in the future?
Who would love such a scruffy, beastly plant?
The life of a thistle
Pitcher thistle spends 3 to 11 years as a small rosette, preparing for its final year, where it will send up a central stem, flower and produce seeds, and then die.
The seeds are carried by the wind and often create colonies near the mother plant, a reminder of its heritage. However, they can also be moved or transported great distances, ensuring their own space in the sun.
It blooms in June and July, occasionally into August, and the bloom is a cotton candy pink tuft escaping from a tight bud.
Its leaves are linear, fuzzy green and project at certain angles from the stem to maximize sun exposure.
The spikes on the tips of the leaves give the thistle an air of indifference.
Working in the field, I observe a mature thistle that has just set seed for the first and only time. I look around for a basal rosette or seedlings of other nearby thistles that will one day take their place.
A sensitive species
First classified as endangered in 2004, its status was reaffirmed in 2008 under the Ontario Act. Endangered Species Act. It was reclassified in 2011 as threatened in the province. NatureServe confirmed it was globally vulnerable in 2020.
Today, there are only four populations of caster thistle in national or provincial parks.
While we may be accustomed to thinking of parks only in terms of recreation, it is equally important to remember that Ontario’s parks provide refuge and continuity for many at-risk species that, for one reason or another, have lost their traditional habitats, often due to anthropogenic causes. human) reasons.
Although the pitcher thistle is endemic to the Great Lakes, the only known Canadian populations are found along the eastern shores of Lake Huron and Lake Superior.
Globally, only the United States and Canada consider themselves home.
It grows in dynamic beach environments, preferring dry, loose sand and open spaces. It is immediately apparent what threatens this beauty: the extremely limited range and specialized habitat it requires.
You see, once the open areas it prefers are closed off with vegetation, the pitcher thistle packs its bags.
Discovering your purpose
I continue to look at the thistle and watch the bees visit the flowers for short intervals.
Some flies join the party, too busy to stay for long.
As I watch the many insect friends fluttering around, it hits me. I remember something I had once read about the pitcher thistle: it becomes the highest number of insect visits of any other plant species that lives in the dunes. In an area of low species diversity, this plant has a significant relationship with not just one, but many insects.
The dunes are not an environment suitable for everyone; This is one of the reasons for the lower richness of species that live here.
Another is that native thistles prevent aggressive non-native thistles from establishing.
This means that plants like caster thistle help protect the dunes from the establishment and control of invasive species, leaving space in the sun for other native plant species.
Caster thistle colonies also protect sensitive dune formations in other ways. For example, humans are less likely to roam in areas where known irritants such as thistle, nettle, and poison ivy are present, reducing trampling and dune erosion.
I continue to stare deeply into the slender broth and velvety leaves until a songbird feeding on thistle seeds flies past me, interrupting my investigative reflection.
I realize that the lesson for us is that not every purpose is to serve humans.
Raising your profile
Lower Ontario Endangered Species ActIts status is “threatened,” meaning it is no longer classified as “endangered,” but may become so if steps are not taken to address factors that threaten to lead to its extinction or extirpation.
He Endangered Species Act protects both the plant and its habitat. In 2013, the province adopted the federal recovery strategy for Pitcher’s Thistle. This strategy was created using the expertise of academics and conservation professionals.
The species-specific policy for caster thistle, known as the Government Response Statement (GRS), was published in 2014 and includes the government’s recovery goal for the species and the actions and priorities it is leading or supporting to help achieve that goal. The GRS considers the scientific advice provided in the recovery strategy, when developing recovery actions for the species.
This strategy recommends public education campaigns that include the installation of signage to increase public understanding.
In 2015, Ontario developed a habitat regulation that defines areas that receive protection as caster thistle habitat.
Threats include both natural (dune succession, deer grazing) and human (dune modification, trampling, and all-terrain vehicle use) impacts. Currently, Ontario has seen an increase in thistle populations at select sites and a decline at others.
Monitoring activities in Inverhuron Provincial Park have provided useful data for tracking changes over time. Over the past four years, we have seen a stable population of between 1,026 and 1,372 individuals in five discrete locations. Compared to the previous year, our numbers increased by 139 people in 2022.
This is a remarkably positive trend, but there is still a cloud that lingers over the pitcher’s thistle.
Here comes the Sun
We can all make decisions that protect the spearing thistle and other at-risk species.
Indigenous teachings are very reflective in the sense that they not only look back, but also forward to ensure that the environment remains intact and sustainable for future generations.
They encourage us to help plants by starting new colonies in new areas of similar habitats.
Being aware of the cumulative impacts of human alterations is another.
One person walking the dune or picking a wildflower once may not be so bad, but the effects are compounded if everyone walks the dunes and picking wildflowers.
Damage gains momentum over time the less aware we are.
Parks alone are not enough to protect threatened species
Protecting species at risk and their habitats is a shared responsibility. There are many small but significant changes we can make in our daily lives that will have a positive impact.
To help Pitcher’s Thistle, stay on official trails and boardwalks, especially in dune ecosystems.
This protects the dunes from erosion and the plants from trampling. By doing this, you will partner with Pitcher’s Thistle to keep this special habitat intact.
Not near the dunes? Plant native plant species where you live and keep your camping gear clean so you don’t bring invasive species to the places you visit.
Help parks and community groups remove invasive species, like phragmites, that could take over places like pitcher thistle habitat.
There is no quick fix that can recover and manage all of Ontario’s threatened species. It will take all of our cooperation to save them.
If we lose the pitcher thistle, what will happen to all the pollinators that visit us?
Who else would protect the delicate dune habitat from damage? What will we lose if the casting thistle no longer takes its place in the sun?
Learn more about pitcher thistle and efforts to protect it:
This is the tenth edition of our 2023 Species at Risk series.
Read our previous edition: Charismatic or not charismatic…that is the question