Developmental timing of flash drought influences offspring survival in the field

Extreme climate events, including rapid-onset flash droughts, are
increasing with anthropogenic climate change. Flash droughts impact growth
and survival of plants, microbes, and invertebrates, yet less is known
about their ecological consequences in vertebrates. Although constant
water deprivation during vertebrate embryonic development influences a
range of offspring traits, the effects of acute, short-term hydric stress
are less well-studied, particularly in the context of subsequent survival
in the field. In this study, we combined experimental manipulation in the
laboratory with a large-scale field experiment to examine the effects of
the developmental timing of flash drought in an oviparous vertebrate
model. We exposed common snapping turtle (Chelydra serpentina) eggs to
simulated flash drought events at different stages of embryonic
development and measured the effects on growth and offspring phenotypes.
We then conducted an experimental release in the field to evaluate
offspring survival during migration from the nest. Flash drought during
mid-to-late development decreased egg mass, incubation time, and hatchling
body size, while flash drought during late development substantially
limited post-hatching survival in the field. This study is among the first
to examine juvenile survival effects of flash drought during embryonic
development in a vertebrate system. Our results suggest that early-life
mortality is likely to increase as flash droughts intensify with climate
change. This study contributes to a growing body of research on the
ecological consequences of extreme climate events and highlights the
importance of considering these events in a developmental context.