• Dave Daversa

Confronting the issue of climate

I moved to California to study threats of disease in wildlife, but the wildlife threat I confronted was climate. In other regions I have lived, climate change is talked about and largely accepted, but it is not directly felt. In California, one feels climate change. I felt the solemnity of hazy dawns created by wildfire smoke. I felt the crackling of desiccated vegetation in normally lush alpine meadows of Yosemite. While investigating how a disease-causing fungal parasite was affecting threatened toads, a more urgent question emerged as to what impact drought was having on the moisture-dependent animals.

A seemingly melancholic Yosemite toad (Anaxyrus canorus) found in a meadow near Dog Lake, Yosemite, 2022.

There are many ways in which drought could impact toad survival. The premature drying out of wetlands may cause toad tadpoles to desiccate and die. The lucky ones that make it to metamorphosis may likely be so small and frail as to impede their ability to forage, evade predators, disperse to new habitats, and complete other essential toad activities. A compromised body condition at metamorphosis may also compromise their immune system and make them more susceptible to the parasites that I was studying. One day, the idea occurred me that the variable impacts of drought and parasitism could be explained by energetics.

Energetics is attractive because it is economical. Just as some argue that body weight is a function of calories consumed versus calories burned, the health and behavior of organisms in an energetics model is a function of energy acquired and energy spent. Measuring energy acquisition and expenditure of animals may tell us about how individuals are likely to respond to adverse climate, as well as how their responses impact the chances of achieving the ultimate evolutionary goal: surviving long enough to successfully reproduce.

The hypothesis led me on a path of discourse with different UCLA faculty. Discussions encompassed a range of topics all dealing with climate change, disease risk, and energetics. I decided to try to bring the topics and people together. A group collaboration formed. So did my latest project on how energetics shapes the interactive effects of climate change and disease on species viability.

The hypothesis may or may not pan out. Either way, I feel a genuine sense of the importance in this work. It was never my intention pursue climate change research. I intentionally avoided climate the topic because of it's popularity, and there are many other projects that would better accentuate my research portfolio. Yet, as a research ecologist living in the present world, and in the American West in particular, this work feels necessary. I am convinced of its importance, and more so than any research I have undertaken thus far.

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