Communal nesting under climate change: fitness consequences of higher incubation temperatures for anocturnal lizard

Dayananda, Buddhi, Gray, Sarah, Pike, David, and Webb, Jonathan K. (2016) Communal nesting under climate change: fitness consequences of higher incubation temperatures for anocturnal lizard. Global Change Biology, 22 (7). pp. 2405-2414.

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Communal nesting lizards may be vulnerable to climate warming, particularly if air temperatures regulate nest temperatures. In southeastern Australia, velvet geckos Oedura lesueurii lay eggs communally inside rock crevices. We investigated whether increases in air temperatures could elevate nest temperatures, and if so, how this could influence hatching phenotypes, survival, and population dynamics. In natural nests, maximum daily air temperature influenced mean and maximum daily nest temperatures, implying that nest temperatures will increase under climate warming. To determine whether hotter nests influence hatchling phenotypes, we incubated eggs under two fluctuating temperature regimes to mimic current cold' nests (mean=23.2 degrees C, range 10-33 degrees C) and future hot' nests (27.0 degrees C, 14-37 degrees C). Hot' incubation temperatures produced smaller hatchlings than did cold temperature incubation. We released individually marked hatchlings into the wild in 2014 and 2015, and monitored their survival over 10months. In 2014 and 2015, hot-incubated hatchlings had higher annual mortality (99%, 97%) than cold-incubated (11%, 58%) or wild-born hatchlings (78%, 22%). To determine future trajectories of velvet gecko populations under climate warming, we ran population viability analyses in Vortex and varied annual rates of hatchling mortality within the range 78- 96%. Hatchling mortality strongly influenced the probability of extinction and the mean time to extinction. When hatchling mortality was >86%, populations had a higher probability of extinction (PE: range 0.52- 1.0) with mean times to extinction of 18-44years. Whether future changes in hatchling survival translate into reduced population viability will depend on the ability of females to modify their nest-site choices. Over the period 1992-2015, females used the same communal nests annually, suggesting that there may be little plasticity in maternal nest-site selection. The impacts of climate change may therefore be especially severe on communal nesting species, particularly if such species occupy thermally challenging environments.

Item ID: 45545
Item Type: Article (Research - C1)
ISSN: 1354-1013
Keywords: climate warming, conservation, Hoplocephalus bungaroides, long-term survival, Oedura leseuerii, population viability, predator, prey
Funders: University of Technology, Sydney
Date Deposited: 27 Jul 2016 07:42
FoR Codes: 31 BIOLOGICAL SCIENCES > 3104 Evolutionary biology > 310406 Evolutionary impacts of climate change @ 100%
SEO Codes: 96 ENVIRONMENT > 9603 Climate and Climate Change > 960399 Climate and Climate Change not elsewhere classified @ 100%
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