Biology subjects

Civitello, D. J.

Publications and source records attributed to Civitello, D. J..

3 recordsLinked to original sources

bioRxiv2017

Thermal mismatches explain how climate change and infectious disease drove widespread amphibian extinctions

Global temperatures and infectious disease outbreaks are simultaneously increasing, but linking climate change and infectious disease to modern extinctions remains difficult. The thermal mismatch hypothesis predicts that hosts should be vulnerable to disease at temperatures where the performance gap between themselves and parasites is greatest. This framework could be used to identify species at risk from a combination of climate change and disease because it suggests that extinctions should occur when climatic conditions shift from historical baselines. We conducted laboratory experiments and analyses of recent extinctions in the amphibian genus Atelopus to show that species from the coldest environments experienced the greatest disease susceptibility and extinction risk when temperatures rapidly warmed, confirming predictions of the thermal mismatch hypothesis. Our work provides evidence that a modern mass extinction was likely driven by an interaction between climate change and infectious disease.

ecology↗

bioRxiv2017

Agrochemical pollution increases risk of human exposure to schistosome parasites

Roughly 10% of the global population is at risk of schistosomiasis, a snail-borne parasitic disease that ranks among the most important water-based diseases of humans in developing countries1-3. Increased prevalence, infection intensity, and spread of human schistosomiasis to non-endemic areas has been consistently linked with water resource management related to agricultural expansion, such as dam construction, which has resulted in increased snail habitat1,4-6. However, the role of agrochemical pollution in human schistosome transmission remains unexplored, despite strong evidence of agrochemicals increasing snail-borne diseases of wildlife7-9 and a projected 2- to 5-fold increase in global agrochemical use by 205010 that will disproportionately occur in schistosome-endemic regions. Using a field mesocosm experiment, we show that environmentally relevant concentrations of fertilizer, the common herbicide atrazine, and the common insecticide chlorpyrifos, individually and as mixtures, increase densities of schistosome-infected snails by increasing the algae snails eat (fertilizer and atrazine) and decreasing densities of snail predators (chlorpyrifos). Epidemiological models indicate that these agrochemical effects can increase transmission of schistosomiasis. Hence, the rapid agricultural changes occurring in schistosome-endemic regions11,12 that are driving increased agrochemical use and pollution could potentially increase the burden of schistosomiasis in these areas. Identifying agricultural practices or agrochemicals that minimize disease risk will be critical to meeting growing food demands while improving human wellbeing13,14.

ecology↗

bioRxiv2017

Towards a Global Framework for Estimating Acclimation and Thermal Breadth that Predicts Risk from Climate Change

Thermal breadth, the range of body temperatures over which organisms perform well, and thermal acclimation, the ability to alter optimal performance temperature and critical thermal maximum or minimum with changing temperatures, reflect the capacity of organisms to respond to temperature variability and are thus crucial traits for coping with climate change. Although there are theoretical frameworks for predicting thermal breadths and acclimation, the predictions of these models have not been tested across taxa, latitudes, body sizes, traits, habitats, and methodological factors. Here, we address this knowledge gap using simulation modeling and empirical analyses of >2,000 acclimation strengths from >500 species using four datasets of ectotherms. After accounting for important statistical interactions, covariates, and experimental artifacts, we reveal that i) acclimation rate scales positively with body size contributing to a negative association between body size and thermal breadth across species and ii) acclimation capacity increases with body size, seasonality, and latitude (to mid-latitudinal regions) and is regularly underestimated for most organisms. Contrary to suggestions that plasticity theory and empirical work on thermal acclimation are incongruent, these findings are consistent with theory on phenotypic plasticity. We further validated our framework by demonstrating that it could predict global extinction risk to amphibian biodiversity from climate change.

ecology↗