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Thermal Behavioral Resilience of a Threatened Desert Lizard

Paper Reviewed
Moore, D., Stow, A. and Kearney, M.R. 2018. Under the weather? -- The direct effects of climate warming on a threatened desert lizard are mediated by their activity phase and burrow system. Journal of Animal Ecology 87: 660-671.

Citing the works of Deutsch et al. (2008), Huey et al. (2009) and Sinervo et al. (2010), Moore et al. (2018) introduce their work by stating that "increasing environmental temperatures through climate warming have ... been predicted to result in localized extinctions through exposure to stressful body temperatures." However, they note that "key factors such as thermoregulatory capacity, microclimate variability and the use of refuge sites are often overlooked [when such predictions are made]." Thus, it became their objective to investigate the ability of such factors to mitigate the projected negative impacts of rising temperature on the great desert skink (Liopholis kintorei). The authors' reason for choosing this lizard was that rising temperatures have been hypothesized to have caused recent population extinctions of this desert-dwelling species in recent years.

In pursuing their objective, Moore et al. studied the thermal surface environment of the L. Kintorei habitat at the Newhaven Wildlife Sanctuary in central Australia, Northern Territory. Additionally, they investigated the thermal and mesic conditions of their burrow systems (this species is an obligate burrower that occupies a complex belowground burrow system) and collected field body temperature measurements from adult skink specimens. Using such data, they were able to derive estimates of potential future thermal stress caused by an increase in air temperature.

Results of their analysis led to three main findings, with the authors' reporting that (1) "above-ground temperature does not appear to be limiting surface activity in this species," (2) "an increase in air temperature of 2.8°C by 2070 will actually increase rather than decrease the total potential surface activity times [of L. Kintorei] during dawn and dusk," and (3) "burrow systems provide an exceptional buffer to extremes of temperature and conditions of low humidity," adding that "the burrow system will continue to provide a buffer for this species, with burrow system temperatures remaining below the observed maximum burrow temperature at mid and deep depths."

In light of the above findings, Moore et al. state that "L. Kintorei and the wide range of other taxa that use their burrow systems or that construct their own, even if only at depths of 30 cm, are likely to be buffered from the direct effects of climate warming on body temperature." Given this likelihood, they conclude that "threatening processes other than the direct effect of climate warming must be sought to explain the observed loss of L. Kintorei at some localities." Our translation of this last sentence would be the more direct statement that climate alarmists should stop blaming rising temperatures as the cause of L. Kintorei deaths!

Deutsch, C.A., Tewksbury, J.J., Huey, R.B., Sheldon, K.S., Ghalambor, C.K., Haak, D.C. and Martin, P.R. 2008. Impacts of climate warming on terrestrial ectotherms across latitude. Proceedings of the National Academy of Sciences of the United States of America 105: 6668-6672.

Huey, R.B., Deutsch, C.A., Tewksbury, J.J., Vitt, L.J., Hertz, P.E., Pérez, H.J.Á. and Garland, T. 2009. Why tropical forest lizards are vulnerable to climate warming. Proceedings of the Royal Society of London B: Biological Sciences 276: 1939-1948.

Sinervo, B., Mendez-De-La-Cruz, F., Miles, D.B., Heulin, B., Bastiaans, E., Villagrán-Santa Cruz, M., Lara-Resendiz, R., Martínez-Méndez, N., Calderón-Espinosa, M.L., Meza-Lázaro, R.N., Gadsden, H., Avila, L.J., Morando, M., De la Riva, I.J., Sepulveda, P.V., Rocha, C.F.D., Ibargüengoytía, N., Puntriano, C.A., Massot, M., Lepetz, V., Oksanen, T.A., Chapple, D.G., Bauer, A.M., Branch, W.R., Clobert, J. and Sites, J.W., Jr. 2010. Erosion of lizard diversity by climate change and altered thermal niches. Science 328: 894-899.

Posted 17 June 2018