The Karner Blue Butterfly barely survives along the St Croix River yet made a major comeback in the Albany Pine Bush!
by Madeline Kennedy
Ontario scientist Laurence Packer described the disappearance of the Karner Blues from his Canadian province which happened after a long hot and dry spell. The butterflies went from having a “large and healthy” population to a nonexistent one in a mere four years!
Regarding the relatively new field of climate science, Packer made what may be a very significant statement, that “[E]ven moderate sized populations may not be safe, especially when weather conditions are unusual . . . this point about weather conditions may be particularly important, considering the climatic changes that many expect from global warming.” This makes the pressure to act now to prevent further destruction to the Karner Blue’s precious habitat even more pressing.
Today the Karner Blue butterflies can be found in a few areas across the northern states, from New York to Wisconsin. In spite of many efforts to restore these beautiful creatures, Karner blues (or Lycaeides melissa samuelis) have seen their population drop or in some cases be abruptly and completely wiped out due to pesticides, loss of habitat and other factors.
When we consider the larger picture of butterfly populations broadly, a peer-reviewed article in the journal Science indicated that butterflies across the United States have been in a major decline the last twenty years. This data came from scientists who analyzed several studies, including studies led and organized by citizen volunteers, and finding there was about 22% fewer butterflies from within the 554 species and 12 million butterflies recorded between 2000 and 2020. “Species-level declines were widespread, with 13 times as many species declining as increasing.”
Butterflies are sensitive to change, which on the one hand makes them vulnerable. However, the same factors that lead to fluctuations in their populations can also be a strength and help them bounce back rapidly. Dr. Eliza Grames wrote “Because they have such short generation times, even small conservation steps can make a big difference…” Citing the Karner Blue as a cause for some optimism, Grames wrote further “…one Karner Blue population in the Albany Pine Bush Preserve in New York rebounded from a few hundred individuals in the early 1990s to thousands of butterflies…”
In spite of this local success, it is certain that with continued threats to their habitat across the country, as with the wild lupine plant on which the Karner Blue’s caterpillars feed exclusively, the future of the Karner Blue’s is uncertain. Extreme weather, such as the harsh droughts followed by severe wet seasons reported in Wisconsin have a significant impact on the butterflies and the lupine. The wild lupine itself requires a very specific habitat in which to grow, along the northern edge of lupine’s range within essentially open sand barrens with limited oak and pine trees. Changes in weather patterns can and will continue to impact its abundance and availability for the blues.
Minnesota is as far west as the Karner Blues and lupine is found today. The Whitewater Wildlife Management Area in southeastern Minnesota is the one place the blues remain in the state. In the early 1980s, there was another population on the edge of the St. Croix River watershed when a road was built that wiped out the wild lupine causing the butterflies to disappear there.
The very particular type of landscape Karner Blues require has been all but eradicated the last couple hundred years. Land gets used for agriculture, trees grow over open land without fires or other disturbances to clear it, climate change leads to dramatic changes in temperature, precipitation and seasonal timing which can all quickly disrupt Karner Blues chances of survival.
In 2019 the U.S. Fish and Wildlife Service stated that the blue’s should remain on the endangered species list because their ‘recovery unit’ populations had disappeared in Minnesota and Indiana. And while some populations showed improvement, others stayed low or are on the decline. Some of the main threats to the blue butterflies’ chances of survival listed in the report included, “loss of habitat due to natural succession, lack of management, invasive species and commercial, industrial and residential development.”
That having been said, from St Croix River to right here in Albany New York , the story clearly isn’t over for the Karner Blue butterflies. With prescribed burns to keep sandy grasslands open, purchasing and protecting lands on which they inhabit, managing the land properly, encouraging lupine to grow along with other flower species that the adult blue’s feed on, efforts to preserve these mystical “blue snowflakes” of the natural world will surely continue and their populations can be restored and preserved for future generations.
Find the full article and references at: The Karner Blues: Endangered butterfly barely survives along St. Croix River as similar species also struggle at www. stcroix360.com.
