Located on the southern shores of Lake Huron in Grand Bend, Ontario, Pinery Provincial Park represents a unique and diverse landscape filled with rare ecosystems, such as oak savannas and freshwater coastal dunes. These ecosystems hold deep importance to Canada’s natural heritage, housing many at-risk flora and fauna. This fact cannot be truer for our bumble bees – Pinery is the last known location of the Endangered rusty-patched bumble bee (Bombus affinis) in Canada (last observed in 2009) and the Endangered Ashton’s cuckoo bumble bee (Bombus bohemicus) in Ontario (last observed in 2008).

So, when Wildlife Preservation Canada’s Native Pollinator Initiative began establishing bumble bee community science programs, hosting one at the Pinery seemed like a no-brainer! We can simultaneously engage local communities in bumble bee conservation, fill knowledge gaps with the aid of dedicated volunteers and continue searching for imperiled bumble bee species in this key area. We may even be lucky enough to find the rusty-patched and Ashton’s cuckoo once again!

Two of Canada’s Endangered bumble bees: the rusty patched bumble bee (left, photo: Susan Carpenter) and Ashton’s cuckoo bumble bee (right, photo: Sheila Colla). The Pinery represents the last known location for these species in Canada and Ontario, respectively.

If you’ve kept up with WPC’s buzzworthy work, you might be familiar with BumbleBeeWatch.org. Bumble Bee Watch is an interactive community science project that monitors bumble bees across North America and is what we use to record and verify bumble bee observations gathered by our community science volunteers. This growing database is used by experts in bumble bee conservation efforts across the continent, and currently has over 167,000 submissions to date. Using Bumble Bee Watch, we can examine the observations collected through the Pinery community science project across all years (2015-2023) and delve into some important questions.

What are we seeing?

Since the Pinery program’s inception in 2015, volunteers have recorded 3,761 bumble bees which have been expert verified on Bumble Bee Watch. This represents a sizable portion of all Ontario submissions to Bumble Bee Watch, with ~19% coming directly from the Pinery community science program.

In total, 10 bumble bee species have been observed through the program (see table below). A handful of species have been recorded each year: the two-spotted bumble bee, the brown-belted bumble bee, the common eastern bumble bee and the half-black bumble bee. Excitingly, the lemon cuckoo bumble bee, a naturally rare species, has been observed each year except 2020. Moreover, the yellow bumble bee, another rare species, has been found twice; once in 2019 and once in 2022. The American bumble bee has been recorded in four separate years: 2017, 2019, 2020 and 2021. This species is of greater significance as it is designated as Special Concern – it is always a pleasure when our volunteers photograph this beautiful bee!

Bumble bee species observed (denoted by X) by volunteers in each year of the Pinery bumble bee community science program.

An American bumble bee (Bombus pensylvanicus; Special Concern) found by one of our Pinery volunteers in 2021 and submitted to Bumble Bee Watch. Photo: Sarah Litterick

From these confirmed IDs, ~58% were the aptly named common eastern bumble bee; by far the most frequently observed species (see graph below). Other commonly encountered species were the brown-belted and two-spotted bumble bees, representing ~20% and ~18.5% of the total records, respectively. These three species alone (out of the 10 recorded) comprise a staggering ~96.5% of all observations over these eight years. Despite seeing the lemon cuckoo bumble bee almost every year, their records only constitute ~1.2% of the total. Similarly, the half-black bumble bee represents only ~1.5% of the total, despite being found in every year of the program. The Special Concern American bumble bee has been observed 15 times, and interestingly, 12 of these were recorded in 2020 at a single site. It is likely that one or more nests were established within that site area at that time, resulting in this higher concentration of American bumble bee observations.

Percent of total observations for each species recorded during the Pinery Provincial Park bumble bee community science program (2015-2023). The number of records for each species is noted above their respective percentage bars. Bumble bee species are ordered from most frequently observed to least. Record numbers in red denote a species that is locally rare/uncommon and those with * have been federally assessed as at-risk.

Where are we seeing them?

When it comes to monitoring bumble bee populations, knowing where they are being found is just as important as knowing what is being found. Locational data allows us to make meaningful ecological inferences. What habitats are being used by bumble bees throughout the park? To what extent are these habitats used or managed by people? These questions and perhaps dozens more could be investigated through locational data. Other important questions to consider here relate to the implementation of the community science methods itself. Are any of these sites more accessible to volunteers than others? Are any sites more appealing to volunteers? We can expect some sites to naturally produce more bumble bee observations than others – perhaps volunteers return to those sites more frequently so they can record more bees. Questions like these allude to the reality that survey effort is unequal across our sites. There is nothing wrong with this, however we must keep such considerations in mind to avoid making faulty conclusions.

In the Pinery community science program, our survey sites are organised into four groups, each with four sites (16 sites total). Sites have changed over the years; however, the map below provides a good visual representation of where bumble bees are being found.

Bumble bee observations (n = 3,761) recorded through the Pinery bumble bee community science program (2015-2023), aggregated by approximate site location. Map created through ArcGis Online and ESRI using data from Bumble Bee Watch.

When examining the map above, the first thing that I noticed is the enormous circle along the beachfront with 813 observations (~ 26.2% of all observations). This circle is actually a single site; some other circles (like the 397 in the middle of the map) are actually observations from more than one site, because some sites are closer together than others. So, what is it about this site area that resulted in so many observations?

The beaches at Pinery are composed primarily of freshwater coastal dunes, while the interior areas of the park are a mix of forests and oak savanna. The beaches provide an edge effect, and forest edges are associated with higher plant diversity and, by extension, pollinator activity. Forests are necessary for bumble bees as they provide nesting and overwintering habitat, however the flowers growing along the forest edges provide food resources. With this in mind, we would expect there to be more bumble bee observations along the beach sites since floral abundance is likely higher there. However, the other beach sites did not experience the same abundance of bumble bee observations.

This is likely due to a combination of natural ecological effects (this site might be of higher quality) and human bias. This site is in the day use area, is a short walk from nearby parking, and is next to two comfort stations. It is a very accessible and enticing choice for a survey – who wouldn’t want to stroll along a beautiful beachfront capturing bees? Some other beachfront sites are embedded within campgrounds, relatively far from parking and other visitor amenities.

To further this point, we can examine the other clusters with many observations. The circles with 269, 347, and 397 observations represent sites that are nestled conveniently in the heart of the park, near the store and visitor centre. Similarly, the circle with 370 observations is located at the park entrance, making this site easy to access and survey. Human bias aside, we also see a clustering of observations in the west of the park, with 449 observations. This site area is described as a Carolinian ecosystem, with forest, meadow, and transitional habitat. To me, this sounds like a great recipe for successful bumble bee surveys! It is no surprise that so many bees have been recorded there, despite being comparatively out of the way.

Successful monitoring is not just the continued surveillance of high-quality sites that produce lots of observations. Although some sites shown here produced few bumble bee observations, it is important to continue monitoring these sites as well to fully grasp the state of bumble bee populations within the Pinery.

I’d like to thank all our volunteers that helped contribute these valuable bumble bee observations over the past eight years. There is no program without you!

Stay tuned for announcements regarding our community science programs in 2024!

Learn more about Pinery’s habitats from The Friends of Pinery Park

We need your help

Donate to save endangered species