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The Likelihood of a Tropical Rainforest Lizard to Endure Climate Change

Paper Reviewed
Llewelyn, J., MacDonald, S.L., Moritz, C., Martins, F., Hatcher, A. and Phillips, B.L. 2018. Adjusting to climate: Acclimation, adaptation and developmental plasticity in physiological traits of a tropical rainforest lizard. Integrative Zoology 13: 411-427.

Introducing their paper, Llewelyn et al. (2018) write that, given model-based predictions of future climate change, it has become a pressing issue to "understand how, and to what extent, animals can adjust their physiology to climate" so as to "predict how species will respond to continuing climate change, as well as [to determine] the best conservation strategies to help them persist." And this this regard, they say set out to study "seven climate-relevant physiological traits in a low dispersal, tropical lizard, the rainforest sunskink (Lampropholis coggeri)." Climate alarmists postulate that ectotherm animals like the sunskink, which are unable to internally regulate their body temperature, are particularly vulnerable to climate change and so a study of this tropical lizard would provide valuable insight in this regard.

To accomplish their objective, the team of six researchers compared traits in two sunskink populations from north-east Australia inhabiting two different climate regimes. The seven traits studied included (1) critical thermal minimum, (2) thermal optimum for sprint performance, (3) maximum sprint performance, (4) performance breadth, (5) critical thermal maximum, (6) heat shock response and (7) desiccation rate. For each trait, the authors tested whether or not it (a) acclimates to lab conditions, (b) shows developmental plasticity driven by egg incubation temperature and (c) shows persistent fixed population differences after acclimation and through one generation in a laboratory setting.

In discussing their findings, Llewelyn et al. say that, "overall, our data demonstrate remarkable lability in the climate relevant traits of rainforest sunskinks," noting that "this lability occurs through multiple pathways (rapid reversible plasticity, acclimation, adaptation, and, to a much lesser extent, developmental plasticity) and it also likely mediated by other traits (such as behavior) that we did not measure here." Nevertheless, they continue, "although sunskinks are tropical ectotherms, and so should be relatively specialized to stable conditions, we see a clear capacity for these specialized trait values to shift." Consequently, they ultimately conclude that "topical extotherms may be capable of rapid shifts in climate-relevant traits," which will help to maintain their populations if future projections of climate change prove valid.

Posted 27 December 2019