Resilience to Droughts in Mammals: A Conceptual Framework for Estimating Vulnerability of a Single Species
Résumé
The frequency and severity of droughts in certain areas is increasing as a consequence of climate
change. The associated environmental challenges, including high temperatures, low food, and water
availability, have affected, and will affect, many populations. Our aims are to review the behavioral,
physiological, and morphological adaptations of mammals to arid environments, and to aid researchers
and nature conservationists about which traits they should study to assess whether or not their study
species will be able to cope with droughts. We provide a suite of traits that should be considered when
making predictions about species resilience to drought. We define and differentiate between general
adaptations, specialized adaptations, and exaptations, and argue that specialized adaptations are
of little interest in establishing how nondesert specialists will cope with droughts. Attention should be
placed on general adaptations of semidesert species and assess whether these exist as exaptations in
nondesert species. We conclude that phenotypic flexibility is the most important general adaptation
that may promote species resilience. Thus, to assess whether a species will be able to cope with increasing
aridity, it is important to establish the degree of flexibility of traits identified in semidesert species that
confer a fitness advantage under drying conditions.