Expanding forests in the Canadian Rocky Mountains are slowly isolating groups of alpine butterflies from each other, leading to a possible extinction of the colourful insects in some areas, according to a new study by entomologists from the University of Alberta.
Washington, Aug 14 : Expanding forests in the Canadian Rocky Mountains are slowly isolating groups of alpine butterflies from each other, leading to a possible extinction of the colourful insects in some areas, according to a new study by entomologists from the University of Alberta.
A rising tree line in the Rockies due to global warming, and a policy not to initiate "prescribed burns" in order to manage forest growth, has created the tenuous condition for the alpine butterflies, said Jens Roland, a University of Alberta biological scientist in his study in the Proceedings of the National Academy of Sciences (PNAS).
The alpine Apollo butterfly (Parnassius) inhabits open meadows because they, like other types of butterflies, need sunlight to generate enough body heat in order to fly, and forests being too shady, inhibit their ability to move.
However, expanding forests are pinching off the Parnassius from their neighbours in nearby meadows.
"The risk of local extinction and inbreeding depression will increase as meadows shrink, the population sizes decrease and the populations become more isolated," said Roland.
"The gene pool of this species is getting more and more fragmented, and gene flow is reduced, which means these populations are more vulnerable," he added.
He said one particularly cold winter or summer season could be enough to wipe out an entire meadow of Parnassius.
He said though the Parnassius is not currently a threatened species, but they and smaller species native to Rocky Mountain meadows, including some insects and rodents, which will suffer "consequences" if forests continue to expand unchecked.
"Often forest management practice is led by the needs of larger species, such as mountain sheep, elk and grizzly bears, while the interests of the smaller species, such as butterflies, are overlooked," said Roland.
"It's important to study movement among populations that are becoming more and isolated due to shrinking habitats; but, ultimately, we need to study the population dynamics to find out if the habitat allows the species to reproduce and persist," he added.
ANI