Beyond Single-Metric Assessments: Uncovering Masked Butterfly Declines via Multi-Scalar Analysis in Central Alberta

A 21-year study of butterfly populations in Central Alberta has revealed hidden declines in biodiversity that traditional single-metric assessments fail to uncover. By combining long-term data with detailed 2021-2025 sampling, researchers discovered significant drops in Shannon Diversity, a diversity measure that standard metrics of species richness and evenness can miss.

This diversity loss was primarily caused by the collapse of the Common Ringlet butterfly over a prolonged period. While four other dominant species--the Cabbage White, Clouded Sulphur, European Skipper, and Common Wood Nymph--remained stable, their populations were limited by extreme winter temperatures and rapid spring warming.

Detailed analysis of the 2021-2025 data showed that community indices and individual species abundances were strongly affected by daily weather conditions, especially wind speed and temperature. These findings suggest that while traditional metrics like species richness and evenness are essential in ecology, they are inadequate when used alone; they work best as part of a broader, multi-scale framework.

The study emphasizes the importance of combining historical datasets with fine-scale, high-frequency monitoring to better understand community changes. It also stresses the value of citizen science in monitoring environmental impacts and setting conservation priorities for insects.