Dave's Research Website
Research Themes
Summary: My research investigates stress in wild animals, with the goal of understanding species resilience to environmental change. Stressors, from extreme weather to infectious disease, afflict wild animals as they do humans. Even when stressful events are not catastrophic, they cause costly physiological changes that can lead to progressive declines in health, survival, and fitness. For now, wild animal populations may be surviving with global change stressors, but are they thriving?
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Wildlife Infectious Disease
The majority of my research has investigated stress in the context of parasitism. Parasites threaten homeostasis and thus act as stressors. Amphibians and the fungal parasite Batrachochytrium dendrobatidis (Bd) were a powerful case study in how a stressor interacts with host ecology at the levels of organisms, populations, and communities. Bd is the causal agent of the disease chytridiomycosis, a main driver of global amphibian declines that has caused more species losses than any other known parasite. My studies of Bd contributed a body of literature on interactions between host movement and infection risk, the community ecology of parasitism, and conservation of rare species.
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Research Framework. My studies link organism-level stress responses to population- and community- level processes through interdisciplinary work that combines field studies, laboratory experiments, genomics and modelling.
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Spiny Common Toads (Bufo spinosus) in amplexus while being radio-tracked to monitor their disease status.
Sierra de Guadarrama, Central Spain, 2009.
The Ecology of Fear
Ecologists have long recognized that
predators, humans, and other biological
stressors elicit so-called ‘fear’ – avoidance
of perceived threats – in wild animals and
that fear alone can have non-lethal
behavioral and physiological effects, with
downstream consequences to fitness,
population demography, and community structure. My research investigates ecological impacts of fear in the context of parasitism, predation, and human disturbance. I am currently developing epigenetic assays to characterize the lifetime health and fitness consequences of living chronically in states of fear.
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​Ecological Epigenomics
Drawing on advances in human health and aging research, my current research takes an epigenomics approach to determining how sublethal stress affect species resilience. The epigenetic process of DNA methylation is involved in the physiological stress response, affects gene expression, and is a powerful biomarker of aging. Studying methylation is likely to transform our understanding stress recovery and adaptation, but integration into eco-evolutionary frameworks has been slow. I am leading this integration through projects that are determining the epigenomic basis of wildlife responses to urban stressors (novel predators, human disturbance) in Greater Los Angeles.
The basis of an epigenetic clock for western toads (Anaxyrus canorus), which estimates biological aging
