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Unexpected Biological Resilience to Climate Change
Bell, R.C., Parra, J.L., Tonione, M., Hoskin, C.J., Mackenzie, J.B., Williams, S.E. and Moritz, C. 2010. Patterns of persistence and isolation indicate resilience to climate change in montane rainforest lizards. Molecular Ecology 19: 2531-2544.

The authors write that tropical species have long been considered to be "especially sensitive to climatic fluctuations because their narrow thermal tolerances and elevational ranges can restrict their ability to persist in, or disperse across, alternate habitats," a concept that NASA's James Hansen expressed much more bluntly by declaring on 21 November 2006 -- when accepting the World Wildlife Fund's Duke of Edinburgh Conservation Medal at St. James Palace in London -- that "species living on the biologically diverse slopes leading to mountains will be pushed off the planet" as the planet warms, opining that there will simply be no place else for them to go.

What was done
In an empirical probe into the substance of this concept, Bell et al. compared "responses to historical climate fluctuation in a montane specialist skink, Lampropholis robertsi, and its more broadly distributed congener, L. coggeri, both endemic to rainforests of northeast Australia," by combining "spatial modeling of potential distributions under representative palaeoclimates, multi-locus phylogeography and analyses of phenotypic variation."

What was learned
The seven scientists found that "both species exhibit pronounced phylogeographic structuring for mitochondrial and nuclear genes, attesting to low dispersal and high persistence across multiple isolated regions." And speaking more specifically about L. robertsi, they state that their evidence demonstrates "persistence and isolation" of most populations of the montane species "throughout the strong climate oscillations of the late Pleistocene, and likely extending back to the Pliocene."

What it means
Noting that many of the isolated refugia they studied "are particularly rich in narrowly endemic species," Bell et al. state that this characteristic has been attributed to "their relative stability during recent episodes of climate change (Williams and Pearson, 1997; Yeates et al., 2002; Graham et al., 2006; VanDerWal et al., 2009)." And they indicate that these observations "support the general hypothesis that isolated tropical montane regions harbor high levels of narrow-range taxa because of their resilience to past climate change," citing the work of Fjeldsa and Lovett (1997) and Jetz et al. (2004). Thus, they write that "at first sight, species such as L. robertsi would seem especially prone to local extinction and loss of considerable genetic diversity with any further warming; yet, these populations and those of other high-montane endemic species (Cophixalus frogs; Hoskin, 2004) have evidently persisted through past warming events." And so it is likely that they will do so again, if similarly stressed in the future, in spite of the overly-confident contentions of James Hansen and company to the contrary.

Fjeldsa, J. and Lovett, J.C. 1997. Biodiversity and environmental stability. Biodiversity and Conservation 6: 315-323.

Graham, C.H., Moritz, C. and Williams, S.E. 2006. Habitat history improves prediction of biodiversity in rainforest fauna. Proceedings of the National Academy of Sciences, USA 103: 632-636.

Hoskin, C.J. 2004. Australian microhylid frogs (Cophixalus and Austrochaperina): phylogeny, taxonomy, calls, distributions and breeding biology. Australian Journal of Zoology 52: 237-269.

Jetz, W., Rahbek, C. and Colwell, R.K. 2004. The coincidence of rarity and richness and the potential signature of history in centers of endemism. Ecology Letters 7: 1180-1191.

VanDerWal, J., Shoo, L.P. and Williams, S.E. 2009. New approaches to understanding late Quaternary climate fluctuations and refugial dynamics in Australian wet tropical rain forests. Journal of Biogeography 36: 291-301.

Williams, S.E. and Pearson, R.G. 1997. Historical rainforest contractions, localized extinctions and patterns of vertebrate endemism in the rainforests of Australia's wet tropics. Proceedings of the Royal Society of London Series B - Biological Sciences 264: 709-716.

Yeates, D.K., Bouchard, P. and Monteith, G.B. 2002. Patterns and levels of endemism in the Australian wet tropics rainforest: evidence from flightless insects. Invertebrate Systematics 16: 605-661.

Reviewed 27 October 2010