An endangered butterfly species in eastern Canada appears to be declining in numbers, but a better understanding of how environmental conditions affect its lifecycle may better inform conservation efforts, according to a new study in Environmental Entomology.
Coenonympha nipisiquit, also known as the maritime ringlet, lives in just 10 salt marshes in Quebec and New Brunswick, Canada, and was first listed as endangered in New Brunswick in 1996. Between 2011 and 2015, visual counts were conducted on a daily basis during the butterfly’s flight period in four of those marshes, and the resulting data revealed declining numbers overall.
“The maritime ringlet is still at risk of extirpation from its natural range, despite conservation efforts and past introductions of the species into unoccupied salt marshes. As such, the current conservation efforts should be reinforced or re-evaluated,” says Gaétan Moreau, Ph.D., associate professor in the department of biology at Université de Moncton in New Brunswick and co-author of the study.
The population monitoring of C. nipisiquit also recorded air temperatures (both during counts and daily high and low temps), wind speed, and rainfall, allowing Moreau and co-author Billie Chiasson to determine that the mid-July beginning of the butterfly’s flight period is largely linked to sustained average temperatures above 7 degrees Celsius (44.6 Farenheit) after snow and ice melt in mid-May. (Specifically, C. nipisiquit adults tended to emerge after 400 degree days accumulated over 7 degrees Celsius after Julian day 130.) They did find some variation, however, between the different marshes, which they suspect may be tied to other ecological factors in each area. Further studies of those factors may be difficult, though, Moreau says, because the endangered status of the species prohibits the kind of manipulations such research would require.
“The identification of some of the environmental factors affecting the demography and detection of this species could guide future monitoring and conservation efforts,” says Moreau. “Ultimately, the most important impact of the study is to bring back to the forefront the delicate situation we are facing with this butterfly.”
Moreau says he and Chiasson “are indebted” to the three organizations that have been conducting the daily counts of the maritime ringlet: Chaleur Bay Watershed, Daly Point Nature Reserve, and Gestion H2O. “We are currently examining the potential of the data for the development of prediction models for ringlet emergence and flight. Meanwhile, daily summer counts of the maritime ringlet are still ongoing and could lead to further analyses,” Moreau says.