Data for: Canopy coverage, light, and moisture affect thermoregulatory trade-offs in an amphibian breeding habitat

When amphibians thermoregulate, they face a fundamental trade-off between
the ability to maintain activity and an increased rate of dehydration at
higher temperatures. Canopy coverage affects both the thermal and hydric
conditions of the environment and can therefore influence amphibian
thermoregulation. Frogs require proper conditions to thermoregulate to
successfully grow, survive, and reproduce. But while we know how canopy
and environmental variables typically affect operative temperature, less
is known about the effects on amphibian water loss rates. In this study,
we measure the effect of canopy coverage on the conditions available for
thermoregulation at a breeding pond of the California red-legged
frog, Rana draytonii. We use agar frog models to estimate the
thermal and hydric capacities frogs would experience in locations with
different canopy coverage and microhabitats. At each site, we deployed
models under four microhabitat treatments: wet/sun, wet/shade, dry/sun,
and dry/shade. We modeled how environmental variables affected operative
temperature and evaporative water loss from agar frogs. We found positive
effects of air temperature, the sun treatment, and reduced canopy cover on
operative temperature, and negative direct or indirect effects of these
variables on evaporative water loss, consistent with the hypothesized
trade-off between thermoregulatory behavior to increased temperature and
the increased desiccation risk due to higher water loss. Additionally, our
results indicate that the availability of wet microhabitats can allow
frogs to reduce water loss, potentially mitigating the risk of desiccation
when thermoregulating to achieve higher operative temperatures. Our
findings suggest, that with access to proper microhabitats, amphibians can
mitigate the fundamental trade-off and receive benefits of
thermoregulating at high temperatures.