It Takes a Village: Citizen Scientists Monitor Canada’s Favourite Butterfly

A monarch butterfly spotted in Île aux Chats, Quebec (image courtesy of eButterfly)

Have you noticed that you are seeing fewer monarch butterflies on your summertime walks? Over the last few decades, the population of monarchs has declined dramatically, leading conservation groups in both Canada and the US to call for the butterfly to be listed as a species at risk.

The monarch famously undertakes a long-distance migration each year between its breeding sites in Canada and overwintering grounds in Mexico. This epic trek would be hard on any animal, but monarchs are also threatened by disease, extreme weather and loss of habitat – making the outlook for this iconic species grim indeed.

According to Prof. Ryan Norris, Department of Integrative Biology, there is no shortage of public interest in saving the monarch butterfly, but you can’t protect a species when you don’t have a good understanding of where it is found.

"We don’t have very good models for the distribution of monarchs, and because they are in decline, this distribution information is important from a basic level,” says Norris. He and his research team recently embarked on a mission to fill this important knowledge gap.

Finding out exactly where monarchs are located across a country the size of Canada is no small task, however. So Norris and his team, including former PhD student and postdoctoral researcher Tyler Flockhart, tapped into a powerful resource: thousands of records of monarch sightings submitted by citizen scientists to two popular databases, eButterfly and Journey North.

The team looked at almost 23,000 citizen science observations of monarchs that were recorded over a 15 year period across the country. They then used the data to build a predictive model of the monarch’s distribution.

The resulting model offers much more than a simple report of where citizen scientists have spotted monarchs. Instead, the model “takes the data of where people have reported monarchs and then extrapolates that across Canada,” says Norris.

The model helps predict where monarchs will be found in a given year and whether they’ll be found there every year, or only occasionally.

As expected, the model showed that most monarchs are located in southern Ontario, even during years of low overall abundance.

“It makes sense that the majority of monarchs are in southern Ontario, because it is the warmest part of Canada,” explains Norris.  “Western parts of Canada are much harder for the monarchs to get to, which is why you only find them there when it’s a high abundance year.”.

The team’s model helps identify those locations that monarchs consistently inhabit – information that is incredibly valuable to organizations which are leading conservations efforts.

The study is an exciting example of how harnessing “people power” through citizen science can help the research community tackle some of its biggest ecological questions. 

“Citizen science is the only way we could have done this research,” says Norris, adding that new technology is helping citizen science become even more relevant. For example, one  public database, iNaturalist, now incorporates artificial intelligence into its program to allow citizen scientists to identify insects and plants, allowing records to be quickly validated.

“Citizen science is becoming really important for ecological studies.”

This study was funded by a Liber Ero Postdoctoral Fellowship and a University of Guelph Research Chair.

Read the full study in the journal Facets.

Read about other CBS Research Highlights.