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Small populations are vulnerable to increased genetic load and drift that can lead to reductions in fitness and adaptive potential. By analyzing 66 individual whole genomes of Montezuma Quail (Cyrtonyx montezumae) from multiple populations, we illustrate how genetic load is dynamic over evolutionary time. We show that Montezuma Quail are evolving like a ring species, where the terminal extant populations from Arizona and Texas have been separated for ~16,500 years. The Texas populations have remained small but stable since the separation, whereas the Arizona population is much larger today but has been contracting for thousands of years. Most deleterious mutations across the genome are young and segregating privately in each population and a greater number of deleterious alleles are present in the larger population. Our data indicate that ancestral load is purged during strong bottlenecks, but the reduced efficiency of selection in small populations means that segregating deleterious mutations are more likely to rise in frequency over time. Forward-time simulations indicate that severe population declines in historically large populations is more detrimental to individual fitness, whereas long-term small populations are more at risk for reduced adaptive potential and population-level fitness. Our study highlights the intimate connections among evolutionary history, historical demography, genetic load, and evolutionary potential in wild populations. [ABSTRACT FROM AUTHOR]

Extreme heat is a recognized threat to human health. This study examines projected future trends of multiple measures of extreme heat across Texas throughout the next century, and evaluates the expected climate changes alongside Texas athletic staff (coach and athletic trainer) attitudes toward heat and climate change. Numerical climate simulations from the recently published Community Earth System Model version 2 and the Climate Model Intercomparison Project were used to predict changes in summer temperatures, heat indices, and wet bulb temperatures across Texas and also within specific metropolitan areas. A survey examining attitudes toward the effects of climate change on athletic programs and student athlete health was also distributed to high‐school and university athletic staff. Heat indices are projected to increase beyond what is considered healthy/safe limits for outdoor sports activity by the mid‐to‐late 21st century. Survey results reveal a general understanding and acceptance of climate change and a need for adjustments in accordance with more dangerous heat‐related events. However, a portion of athletic staff still do not acknowledge the changing climate and its implications for student athlete health and their athletic programs. Enhancing climate change and health communication across the state may initiate important changes to athletic programs (e.g., timing, duration, intensity, and location of practices), which should be made in accordance with increasingly dangerous temperatures and weather conditions. This work employs a novel interdisciplinary approach to evaluate future heat projections alongside attitudes from athletic communities toward climate change. Plain Language Summary: Heat extremes are dangerous for humans, and anthropogenic climate change is making extreme heat events more frequent over time. Future changes in extreme heat may prove particularly dangerous to athletes who participate in outdoor sports, as they are susceptible to exertional heat illness (EHI). This study was spearheaded by a team of undergraduate students at Rice University who were interested in how extreme heat events might impact athletics across the state of Texas. We surveyed hundreds of athletic staff at Texas colleges and high schools to assess their awareness of future heat risks to student athlete health. We compared survey results to climate model projections of summer temperatures and indices like heat index and wet bulb temperatures (variables which consider humidity as well as temperature) across Texas throughout the next century. Heat indices are projected to increase beyond what the National Weather Service considers safe for outdoor sports by the mid‐21st century. Despite the clear trend toward increasingly dangerous hot weather conditions, some athletic staff still do not acknowledge the changing climate and its implications for student athlete health. Climate change communication is needed to initiate changes to athletic programs and reduce the risk of EHIs for athletes in Texas. Key Points: This study examines projected trends in extreme heat across Texas throughout the next century from Community Earth System Model version 2 alongside a survey of athletic staffHeat indices are projected to increase beyond what is considered healthy/safe limits for outdoor sports activity by the mid‐to‐late 21st centuryWhile most athletic staff acknowledge the need for changes to prevent heat‐related illness in student athletes, a smaller portion still do not [ABSTRACT FROM AUTHOR]

Populations with higher genetic diversity and larger effective sizes have greater evolutionary capacity (i.e., adaptive potential) to respond to ecological stressors. We are interested in how the variation captured in protein‐coding genes fluctuates relative to overall genomic diversity and whether smaller populations suffer greater costs due to their genetic load of deleterious mutations compared with larger populations. We analyzed individual whole‐genome sequences (N = 74) from three different populations of Montezuma quail (Cyrtonyx montezumae), a small ground‐dwelling bird that is sustainably harvested in some portions of its range but is of conservation concern elsewhere. Our historical demographic results indicate that Montezuma quail populations in the United States exhibit low levels of genomic diversity due in large part to long‐term declines in effective population sizes over nearly a million years. The smaller and more isolated Texas population is significantly more inbred than the large Arizona and the intermediate‐sized New Mexico populations we surveyed. The Texas gene pool has a significantly smaller proportion of strongly deleterious variants segregating in the population compared with the larger Arizona gene pool. Our results demonstrate that even in small populations, highly deleterious mutations are effectively purged and/or lost due to drift. However, we find that in small populations the realized genetic load is elevated because of inbreeding coupled with a higher frequency of slightly deleterious mutations that are manifested in homozygotes. Overall, our study illustrates how population genomics can be used to proactively assess both neutral and functional aspects of contemporary genetic diversity in a conservation framework while simultaneously considering deeper demographic histories. [ABSTRACT FROM AUTHOR]

Population extirpations are often precursors to species extinctions. Anthropogenic activities often lead to smaller populations that are more prone to extirpations and advocates for active conservation management have recently called for the preservation and monitoring of genetic diversity, particularly with regard to the adaptive potential of vulnerable populations. We used genomics and curated arrays of molecular markers, including those expected to impact key fitness traits, to quantify evidence of genomic erosion in core and peripheral populations of a gallinaceous bird. The Montezuma quail (Cyrtonyx montezumae) is a game species considered vulnerable to extirpation in Texas, but core populations in Arizona and New Mexico are robust and have the potential to serve as genetic reservoirs. We sequenced the Montezuma quail genome then developed a single nucleotide polymorphism (SNP) assay to quantify genetic variation, effective population sizes, signatures of natural selection, and population structure. We genotyped SNPs from gene deserts and from genes associated with fitness traits and found the isolated Texas population exhibits an extremely small effective population size, is genetically distinct from our Arizona and New Mexico samples, and has reduced heterozygosity at the fitness-related markers. Thus, our samples from Texas exhibit symptoms of genetic erosion that could exacerbate future risk of local extirpation. Management agencies must decide if active conservation efforts such as assisted gene flow or genetic rescue are now warranted. This decision may not be straightforward because the current conservation status of the Texas population reflects its isolated geographic locale on the periphery of the species' range. [ABSTRACT FROM AUTHOR]