Background
The author notes that "Atalopedes campestris, the sachem skipper butterfly, expanded its range from northern California into western Oregon in 1967, and into southwestern Washington in 1990," where she reports it has warmed 2-4°C over the past 50 years.

What was done
To assess the importance of climate change (in this case, regional warming) for population persistence of A. campestris in the recently colonized areas, Crozier "compared population dynamics at two locations (at the current range edge and just inside the range) that differ by 2-3°C."  Then, to determine the role of over-winter larval survivorship, she "transplanted larvae over winter to both sites."

What was learned
As Crozier describes her findings, "combined results from population and larval transplant analyses indicate that winter temperatures directly affect the persistence of A. campestris at its northern range edge, and that winter warming was a prerequisite for this butterfly's range expansion."

What it means
Noting that "populations are more likely to go extinct in colder climates," Crozier says "the good news about rapid climate change [of the warming type] is that new areas may be available for the introduction of endangered species."  Her work also demonstrates that the species she studied has responded to regional warming by extending its northern range boundary and thereby expanding its range, which should enable it to move further back from the "brink of extinction" that so many climate alarmists associate with rapid global warming.  See also, in this regard, our major report The Specter of Species Extinction: Will Global Warming Decimate Earth's Biosphere?