Climate change-induced extinctions are estimated to eliminate one in six known species by the end of the century. One major factor that will contribute to these extinctions is extreme climatic events. Here, we show the ecological impacts of recent record warm air temperatures and simultaneous peak drought conditions in California. From 2008–2016, the southern populations of a wide-ranging endemic amphibian (the California newt, Taricha torosa) showed a 20% reduction to mean body condition and significant losses to variation in body condition linked with extreme climate deviations. However, body condition in northern populations remained relatively unaffected during this period. Range-wide population estimates of change to body condition under future climate change scenarios within the next 50 years suggest that northern populations will mirror the loss of body condition recently observed in southern populations. This change is predicated on latter 21^st century climate deviations that resemble recent conditions in Southern California. Thus, the ecological consequences of climate change have already occurred across the warmer, drier regions of Southern California, and our results suggest that predicted climate vulnerable regions in the more mesic northern range likely will not provide climate refuge for numerous amphibian communities.

Extreme weather events are predicted to increase as a result of climate change, yet amphibian responses to extreme disturbance events remain understudied, especially in the Neotropics. Recently, an unprecedented windstorm within a protected Costa Rican rainforest opened large light gaps in sites where we have studied behavioral responses of diurnal strawberry poison frogs (Oophaga pumilio) to ultraviolet radiation for nearly two decades. Previous studies demonstrate that O. pumilio selects and defends perches where ultraviolet radiation (UV‐B) is relatively low, likely because of the lethal and sublethal effects of UV‐B. In this natural experiment, we quantified disturbance to O. pumilio habitat, surveyed for the presence of O. pumilio in both high‐disturbance and low‐disturbance areas of the forest, and assessed UV‐B levels and perch selection behavior in both disturbance levels. Fewer frogs were detected in high‐disturbance habitat than in low‐disturbance habitat. In general, frogs were found vocalizing at perches in both disturbance levels, and in both cases, in significantly lower UV‐B levels relative to ambient adjacent surroundings. However, frogs at perches in high‐disturbance areas were exposed to UV‐B levels nearly 10 times greater than males at perches in low‐disturbance areas. Thus, behavioral avoidance of UV‐B may not reduce the risks associated with elevated exposure under these novel conditions, and similarly, if future climate and human‐driven land‐use change lead to sustained analogous environments.

Color and pattern serve as a range of anti‐predator defense mechanisms across taxa, from crypsis to warning coloration, and these phenomena are well described across invertebrate and vertebrate systems. Coloration is often assumed to have a consistent anti‐predator function across life stages, but research conducted at a single life stage can yield valuable insight into the ecological and evolutionary significance of coloration across shifts in stage‐specific selection pressures. Painted turtles ( Chrysemys picta ) are so named for their striking coloration and patterning. In this study, we use simulated hatchling painted turtles to test the anti‐predator function of shell coloration on land. Using resin models, we demonstrate, for the first time, that plastral patterns have an anti‐predatory function in painted turtle hatchlings in conditions ecologically relevant to nest dispersal. Specifically, turtle models with simple patterns were predated significantly more than their complex‐patterned counterparts. This suggests that plastral pattern may serve as an anti‐predator strategy through background matching or disruptive coloration. These results provide evidence for the poorly understood functional importance of color and pattern variation in this species and demonstrate the need to test the roles of defensive coloration and patterning across life stages to better understand their ecological and evolutionary significance.

Nest predation is one of many factors that contribute to population declines in turtles, a globally imperiled taxon. Nest predation negatively affects juvenile recruitment; thus there is increasing interest in understanding predictors of turtle nest predation across species and contexts, which can be used to inform conservation efforts. In this study, we quantify predation trends on artificial turtle nests deployed within Painted Turtle (Chrysemys picta) nesting habitat, where raccoons (Procyon lotor) are the primary nest predator. We constructed artificial turtle nests without reward and measured nest predation across 4 wk to ask three questions: Do nest predators habituate to unrewarding nest cues over time? Which nest qualities determine nest predation rate in this system, and does the presence of artificial nests reduce predation of real C. picta nests in the same area? We find evidence that predation intensity of artificial nests decreased over time, that nests closer to water edges suffer higher predation, and real nests continue to be depredated at a high rate even when there are more artificial nests without egg reward present. These results contribute to the ongoing investigation of nest cues used by turtle predators, especially raccoons, and provide context for future studies that may employ misinformation cues to enhance turtle nest protection.

Cellular hallmarks of aging have been discovered and characterized in a number of model species for studying aging biology - such as humans, mice, fruit flies, and nematodes. Whether these canonical age-related changes to cellular physiology are present across diverse species that have variable rates of demographic aging remains less studied. Here, we tested whether several ubiquitous cellular hallmarks of aging - mitochondrial function, reactive oxygen species generation, and inducible DNA damage - change with age and in a sex-dependent manner in a species with indeterminate growth and reproduction (painted turtles, Chrysemys picta). A further feature of their biology that recommends them for an ecological model of vertebrate aging is their female-biased longevity, despite an absence of genotypic sex determination. Thus lifespan and aging may be reliable features of sex-specific life-histories. We measured aspects of mitochondrial health (cellular basal, maximal, and spare oxygen consumption rates), cellular levels of reactive oxygen species, and aspects of DNA damage and repair from exposure to UVB. We used these measures across several physiological axes as proxies for age-related physiological dysfunction. We further assessed our measures across several populations of painted turtles. We found that sex explained the largest proportion of variation, with males differing from females in mitochondrial function, reactive oxygen species production, and inducible DNA damage. In several cases, age significantly interacted with sex, but the effect size was small relative to sex alone. Thus, we found that sex, rather than age or size, was a consistent predictor of cellular aging physiological in this species with where females live longer and age slower.