Update on Butterfly Numbers

This is a summary of my 37 years of data on the butterflies of the Pikes Peak Region. The following graphs show trends in abundances as measured by butterflies observed per hour afield. Each data point is a record of the number of butterflies observed per hour of observation time. First, the whole data set for the Pikes Peak Region, with tons of scatter:Regional Trend.png

This shows an almost flat line, but slightly increasing (from 69/h to 78/h). But when I restrict the data to only Bear Creek, where I have spent most of my time, we find:BCC Trenda negative slope (from 87/h to 80/h). And when graphed according to the average number per hour for each year, we get:mean BCC Trend.pnga more negative slope (from 102/h down to 79/h). This is surprising to me, as 11 years at an Austin Bluffs site shows no such decline:AB Trendeven when plotted according to annual averages:mean AB Trend.pngI also created box and whisker plots for the numbers of butterflies per hour for each summer month in Bear Creek!box plot databox plots.png

In sum, butterfly numbers appear generally stable in this region, but further study is always needed as we enter a hotter earth with more fires.

Author: Samuel A. Johnson

This blog is about hiking, thinking, and writing.

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