Summer Warming Impacts on Bees, Moths and Butterflies in Mountainous Northern Scandinavia
Franzen, M. and Ockinger, E. 2012. Climate-driven changes in pollinator assemblages during the last 60 years in an Arctic mountain region in Northern Scandinavia. Journal of Insect Conservation 16: 227-238.
Against this backdrop, Franzen and Ockinger studied temporal changes in the insect species richness and community composition of wild bees, butterflies and moths over a period of 64 years at five different sites in northern Sweden's Padjelanta National Park (one of the largest National Parks in Europe that is located just north of the Arctic Circle, between 66°45' and 67°35'N, and 15°06' and 18°36'E). The insect data were collected during surveys conducted over the period 2006-2008 and were compared with similar data that had been collected in 1998 and 1944, while corresponding climate data were obtained from a weather station located at 66.89°N, 18.02°E. So what did they learn?
With respect to climate, the two researchers determined there had been a significant increase in the daily mean temperature during the vegetation season (May-September) between 1944 and 2008, when the temperature rose at a rate of 0.015°C per year, yielding an increase of almost 1°C over the 64-year study period. With respect to insect responses, they found that the total number of bumble bee, butterfly and moth species increased from 52 in 1944 to 64 in 2008; but they say that for wild bees, which only increased from 15 to 16 species, the increase was not statistically significant. For butterflies and moths, on the other hand, the combined species number increase (from 37 to 48) was statistically significant.
Contrary to the "doom and gloom" prognostications of climate alarmists, Franzen and Ockinger found that "high alpine insect species are apparently still performing relatively well," noting that (1) "both southern species, such as Erebia ligea and Polyommatus icarus, and high alpine species, such as Boloria chariclea and Lasionycta staudingeri, seem to have colonized the area," and that (2) "ranges and species richness are even increasing in our study region, due to retreating glaciers and plant colonizations." And in light of these real-world observations, they say "it is possible that warming will simply improve the performance and abundance of species in cold areas, as their mobility increases and new habitats become available," additionally citing, in this regard, the studies of Ashton et al. (2009), Bale and Hayward (2010) and Kullman (2010).
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Kullman, L. 2010. Alpine flora dynamics: a critical review of responses to climate change in the Swedish Scandes since the early 1950s. Nordic Journal of Botany 28: 398-408.
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