Over the past two years, Butterflyway Rangers in Victoria, Richmond and North Vancouver focused mainly on building pollinator communities. Rangers learned about the importance of planting pesticide-free pollinator plants like native wildflowers for butterflies and wild bees. In the process, they also engaged their communities to build a network of pollinator freeways to help butterflies and wild pollinators find food and shelter wherever they land.
From the start, the national Butterflyway program has had a dual focus: While eastern Rangers focused on helping the dwindling population of monarch butterflies, western Rangers were keen to explore other popular butterfly species that frequent their region.
Early last summer, western Rangers spotted western tiger swallowtails, painted ladies, cabbage whites and the occasional mourning cloak, a small sample of the vast variety of butterflies found in B.C. Meanwhile, according to Crispin Cupin, author of The Butterflies of British Columbia, “There were 187 species and 77 subspecies of butterflies and skippers known from British Columbia by year 2000. … The total butterfly fauna of B.C. should eventually reach 192 and perhaps 196 species.”
Different butterfly species will show up in different geographical areas. But the limited variety of butterfly species seen in and around Butterflyway patches since 2017 caused Rangers to be concerned about the state of B.C.’s butterflies.
What butterfly species live in the Lower Mainland? Are coastal butterfly species different from inland species? What species are missing and why? What kind of environmental challenges do they face? What about western monarchs in B.C.? Where and when can they be spotted, if at all?
These important questions were of particular interest to our Butterflyway Rangers in light of the sharp drop in western monarch populations last year. According to an annual census by the U.S.-based Xerces Society for Invertebrate Conservation, the number of western monarchs dropped by 86 per cent between 2017 and 2018.
Washington State University Vancouver associate professor Cheryl Schultz was one of the researchers in the recent western monarch count in California. She said in the 1980s, an estimated 10 million monarchs wintered in coastal California. In 2017, the 97 sites along coastal California that traditionally host the western monarchs in winter saw about 148,000 monarchs; in 2018, that number dropped to 28,429, with large numbers counted at just three sites.
In a recent interview with the New York Times, biologist Emma Pelton paired the recent free-fall in western monarchs with a 97 per cent decline in the total population since the 1980s: “You’re talking about a ‘potentially catastrophic’ situation.” Monarchs rely on milkweed, Pelton explained, which has been in decline because of pesticide use, urbanization and droughts. Plus, rising temperatures and habitat destruction at the butterflies’ breeding sites in the U.S. and Canada are often cited as major drivers of monarch declines, according to University of Wisconsin – Madison conservation biologist Karen Oberhauser.
If nothing is done to preserve their habitat, western monarchs could face extinction.
What do these latest developments have to do with B.C. Butterflyway Rangers, especially if western monarchs rarely show up in the Lower Mainland?
According to UBC’s Geography Department: “While the western population of monarch butterfly utilizes the Pacific Northwest as part of its migratory flyway to overwintering sites in California, the species is more of an incidental occurrence on B.C.’s Coast Region. A small number of individuals are documented periodically on the South Coast of B.C. (Fraser Lowlands, north to Pemberton) and east to the Lillooet area (where adults and larvae occur in larger numbers). Individuals have also been documented from Vancouver Island. Occurrence and distribution can be tied to wind and weather patterns. Migrating Monarchs are often blown off-course as was likely the case for an occurrence in Tofino. Availability of larval food plants (native and ornamental species of milkweed), often planted as ornamentals in coastal gardens also contributes to the disjunct nature of occurrences on the Coast Region.”
In other words, for B.C. Butterflyway Rangers, there could be truth to the idea, “If you plant it, they will come!”
All this makes the citizen science component of the 2019 Butterflyway Project for B.C. Rangers more urgent and important. In 2019, B.C. Rangers will help identify butterflies through the iNaturalist Butterfly in my Backyard citizen science group.
As 2019 Butterflyway Rangers in Vancouver, Richmond and the District of North Vancouver join the Butterflyway Project, they will help shed more light on these fascinating pollinators and the shape they are in.