Here are the results from two sweep samples of insects taken ten years apart at exactly the same location on the Section 16 Trail west of Colorado Springs. In both cases, 100 sweeps were made. In this area, which is relatively undisturbed in terms of regular application of pesticides, herbicides, and insecticides, total numbers of insects seem very similar after ten years. T-Tests, both one-tailed and two-tailed, show p values that do not suggest significance. I chose a date one week later in 2019, as the season appears a bit behind average in terms of butterfly emergence dates.
As a follow up to my earlier report on the butterflies and diurnal moths of the Pikes Peak Region, I took the advice of Steve Taylor and prepared a graphic of all 255 dates on which I counted butterflies, and on which the time, temperature, and other conditions were favorable to flight. This shows the “noise” encountered in this sort of work, as well as the extraordinary summers of 2012-2014. If there is a trend, it might show up as a decline after 2015, when levels are about as they were early in the study. Note that most of the points from 2015 on fall below the mean score of 72.5/h. However, the overall slope is very slightly up (+0.032x). I can’t wait to continue observations this summer.
If I restrict the data to just the 145 dates that are from Bear Creek Canyon, there is a very slightly different trend, this time downward (–0.12x), from about 91 to 74 over the 35 years. Maybe this is the apocalypse! More later!
For those not tuned in to Southwest Geology, a sill is an igneous intrusive that has inserted itself parallel to the surrounding strata (a dike runs at angles to the strata). Palisade Sill is a huge intrusive in northern New Mexico between Raton and Taos on Highway 64. You won’t miss it when you head west into the canyon out of Cimarron. The sill is made of Monzonite, which is on the continuum between syenite (very light in color) and diorite (medium in color) and has plagioclase and orthoclase feldspars in approximately equal amounts. In short, it is a lighter than granite, but generally similar.
My favorite aspect of this imposing formation is that the joint systems are at nearly right angles, which leaves enormous faces and a ragged, blocky crest at the skyline. And, of course, lots of rubble along the stream below. Here are some images of the crestline.
After 33 years of collecting moths in the Pikes Peak Region, I finally have begun to let it go to the C. P. Gillette Museum in Fort Collins at Colorado State University. The first installment, 36 drawers of mostly Noctuidae (the owlet moths) were shrink-wrapped and dispatched on August 29. One drawer is shown here.
And here is the first load.
And in their new home.
Many more to go in the next few weeks. Sad to see them go, but I know that they’re in a better place. (!)