Comparison of Five Similar Headwater Streams in Central Pennsylvania during the Summer of 2017

Elaine Langone Center, Terrace Room

We compared the benthic macroinvertebrate (BMI) communities between the five headwater streams that flow down the north slope of Penn’s Creek Mountain in Bald Eagle State Forest through the summers of 2015 to 2017. The five headwater streams, Little Weikert Run, Green Gap Run, Lick Run, Coral Run, and Henstep Run are similar in size and substrate (sand, cobble, and boulder) and maintained flow even through the drought conditions of 2016. Alkalinity averaged 72, 190, 178, 205 and 122 µeq/L during the three year study for each of the headwater streams, respectively. They were also similar in conductance averaging 18, 26, 23, 25, and 22 µs/cm, respectively. The %EPT (Ephemeroptera, Plecoptera, Trichoptera), for the five headwaters ranged from 52-75% during the summer of 2017, which given the sites is unexpectedly low. We collected the BMI during the first half of July using the 6-kick method, and processed them by the PA DEP and US EPA protocols. Another common metric is Proportional Bray-Curtis Similarity Index which shows the degree to which the BMI taxa overlap between the five headwater streams. During the summer of 2017 the two most similar streams were Little Weikert and Coral Run (62% overlap), but all stream community comparisons were moderate to high. Based on the collections from the summer of 2017 the five streams are moderate replicates of each other as far as the BMI communities are concerned.