Red-legged frogs and Hydaspe fritillary butterflies

We collected demographic data on populations of frogs and butterflies that span a wide latitudinal and elevational range to encompass areas with differing environmental conditions. The goal was to see how stage-specific demographic rates (survivorship from one stage to the next – like egg to tadpole or caterpillar) vary across locations with different environmental conditions (e.g. temperature and precipitation).  We used this information in combination with climate projection models to predict how the population dynamics of these species will be affected by climate change. This can give land managers and conservationist an idea of which species will be most sensitive to climate change and where to focus conservation efforts.

We had sites that range from the Willamette Valley in Oregon, through coastal Northern California, to the Sierra Nevada foothills near Lake Tahoe, CA. To estimate the survivorship of different life stages of red-legged frogs and Hydaspe fritillaries we measured egg hatch rates, and conducted mark-recapture studies with tadpoles (for the frogs) and adults (for both species).  We marked individuals with a unique ID tag to estimate their survivorship based on how many times we caught them again and over what period. For the frogs, we marked individuals with visible implant elastomer (VIE) tags. This is a flourescent elastomer that comes in different colors and is injected just under the skin. It is non-toxic and does not injure the animals, and it allowed us to give individuals a unique tag by using different color combinations. We tagged tadpoles on the tail and metamorphs and adults between the toes.

For the butterflies we caught adults with nets and wrote on their wings using a fine-tip sharpie marker.