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Extinction (Real-World Observations - Animals: Other Animals) -- Summary
Most analyses of warming-induced animal-extinction probabilities have been directed towards birds and butterflies. There are, however, a few other types of animals that have been studied in this regard; and in this short summary we report some of the things that have been learned from this latter work.

Norment et al. (1999) summarized and compared the results of many surveys of mammal populations observed along the Thelon River and its tributaries in the Canadian Northwest Territories from the 1920s through much of the 1990s. Over this time period, red squirrel, moose, porcupine, river otter and beaver were found to have established themselves in the area, significantly increasing its biodiversity. The three researchers say that the primarily northward range expansions may be explained by "a recent warming trend at the northern treeline during the 1970s and 1980s." Alternatively, they note that the influx of new species may be due to "increasing populations in more southerly areas." In either case, we have a situation where mammals appear to be faring quite well in the face of increasing temperatures in this forest-tundra landscape.

Hickling et al. (2005) analyzed changes in the northern and southern range boundaries of 37 non-migratory British Odonata (dragonfly and damselfly) species -- 4 of which have northern ranges, 24 of which have southern ranges, and 9 of which are ubiquitous -- between the two 10-year periods 1960-70 and 1985-95. This work revealed that all but two of the 37 species increased the sizes of their ranges between the two 10-year periods; and with respect to this observation, they report that their "findings that species are shifting northwards faster at their northern range margin than at their southern range margin, are consistent with the results of Parmesan et al. (1999)," adding that "this could suggest that species at their southern range margins are less constrained by climate than by other factors," which does indeed appear to be the case, as evidenced by the preponderance of evidence discussed in our reviews of bird and butterfly studies. Thus, rather than leading to range reductions as a prelude to a massive extinction of species, as has been claimed by many of the world's climate alarmists to be lurking just around the corner, so to speak, global warming, if it continues for some time and its elevated warmth is maintained, will in all likelihood lead to most of earth's species expanding their ranges and gaining an even stronger foothold on the planet.

Chamaille-Jammes et al. (2006) studied four unconnected populations of the common lizard (Lacerta vivipara), a small live-bearing lacertid that lives in peat bogs and heath lands scattered across Europe and Asia, concentrating on a small region near the top of Mont Lozere in southeast France, at the southern limit of the species' range. More specifically, from 1984 to 2001 they monitored a number of life-history traits of the populations, including body size, reproduction characteristics and survival rates, during which time local air temperatures rose by approximately 2.2C. In doing so, they found that individual body size increased dramatically in all four lizard populations over the 18-year study period, with snout-vent length expanding by roughly 28%. This increase in body size occurred in all age classes and, as they describe it, "appeared related to a concomitant increase in temperature experienced during the first month of life (August)." As a result, they found that "adult female body size increased markedly, and, as fecundity is strongly dependent on female body size, clutch size and total reproductive output also increased." In addition, for a population where capture-recapture data were available, they learned that "adult survival was positively related to May temperature."

In summarizing their findings, the French researchers stated that since all fitness components investigated responded positively to the increase in temperature, "it might be concluded that the common lizard has been advantaged by the shift in temperature." This finding, in their words, stands in stark contrast to the "habitat-based prediction that these populations located close to mountain tops on the southern margin of the species range should be unable to cope with the alteration of their habitat." Hence, they concluded that "to achieve a better prediction of a species persistence, one will probably need to combine both habitat and individual-based approaches," noting, however, that individual responses, such as those documented in their study (which were all positive), represent "the ultimate driver of a species response to climate change."

Last of all (but happening some time ago), Pockley (2001) reported the results of a survey of the plants and animals on Australia's Heard Island, a little piece of real estate located 4,000 kilometers southwest of Perth. Over the prior fifty years this sub-Antarctic island had experienced a local warming of approximately 1C that had resulted in a modest (12%) retreat of its glaciers; and hence, for the first time in a decade, scientists were attempting to document what this warming and melting had done to the ecology of the island.

Pockley began by stating the scientists' work had unearthed "dramatic evidence of global warming's ecological impact," which obviously consisted of "rapid increases in flora and fauna." He quoteed Dana Bergstrom, an ecologist at the University of Queensland in Brisbane, as saying that areas that previously had been poorly vegetated had become "lush with large expanses of plants." And he added that populations of birds, fur seals and insects had also expanded rapidly. One of the real winners in this regard was the king penguin, which, according to Pockley, had "exploded from only three breeding pairs in 1947 to 25,000."

Eric Woehler of Australia's environment department was listed as a source of other equally remarkable information, such as the Heard Island cormorant's comeback from "vulnerable" status to a substantial 1,200 pairs, and fur seals emergence from "near extinction" to a population of 28,000 adults and 1,000 pups.

Yes, the regional warming experienced at Heard Island actually saved these threatened animal populations from the jaws of extinction. So it's time to celebrate! Responsibility clearly cuts both ways; and if emitters of CO2 are being excoriated, and in advance, for presumably promoting future hypothetical extinctions, they should surely be thanked, even in retrospect, for preventing imminent real-world extinctions.

Chamaille-Jammes, S., Massot, M., Aragon, P. and Clobert, J. 2006. Global warming and positive fitness response in mountain populations of common lizards Lacerta vivipara. Global Change Biology 12: 392-402.

Hickling, R., Roy, D.B., Hill, J.K. and Thomas, C.D. 2005. A northward shift of range margins in British Odonata. Global Change Biology 11: 502-506.

Norment, C.J., Hall, A. and Hendricks, P. 1999. Important bird and mammal records in the Thelon River Valley, Northwest Territories: Range expansions and possible causes. The Canadian Field-Naturalist 113: 375-385.

Parmesan, C., Ryrholm, N., Stefanescu, C., Hill, J.K., Thomas, C.D., Descimon, H., Huntley, B., Kaila, L., Kullberg, J., Tammaru, T., Tennent, W.J., Thomas, J.A. and Warren, M. 1999. Poleward shifts in geographical ranges of butterfly species associated with regional warming. Nature 399: 579-583.

Pockely, P. 2001. Climate change transforms island ecosystem. Nature 410: 616.

Last updated 23 December 2009