Habitat heterogeneity affects the thermal ecology of the federally endangered blunt-nosed leopard lizard 2019 data

Global climate change is already contributing to the extirpation of
numerous species worldwide, and sensitive species will continue to face
challenges associated with rising temperatures throughout this century and
beyond. It is especially important to evaluate the thermal ecology of
endangered ectotherm species now so that mitigation measures can be taken
as early as possible. A recent study of the thermal ecology of the
federally endangered Blunt-Nosed Leopard Lizard (Gambelia sila) suggested
that they face major activity restrictions due to thermal constraints in
their desert habitat, but that large shade-providing shrubs act as thermal
buffers to allow them to maintain surface activity without overheating. We
replicated this study and also included a population of G. sila with no
access to large shrubs to facilitate comparison of the thermal ecology of
G. sila in shrubless and shrubbed populations. We found that G. sila
without access to shrubs spent more time sheltering inside rodent burrows
than lizards with access to shrubs, especially during the hot summer
months. Lizards from a shrubbed population had higher midday body
temperatures and therefore poorer thermoregulatory accuracy than G. sila
from a shrubless population, suggesting that greater surface activity may
represent a thermoregulatory tradeoff for G. sila. Lizards at both sites
are currently constrained from using open, sunny microhabitats for much of
the day during their short active seasons, and our projections suggest
that climate change will exacerbate these restrictions and force G. sila
to use rodent burrows for shelter even more than they do now, especially
at sites without access to shrubs. The continued management of shrubs and
of burrowing rodents at G. sila sites is therefore essential to the
survival of this endangered species.