Restoration stream data for amphibian populations at Big Spring Run, Lancaster County, PA

Background/Question/Methods

In order to improve the ecosystem services provided by a stream in an agricultural landscape, a consortium of scientists, state and federal officials, and environmental consultants are conducting an experimental stream restoration project in which legacy sediments are removed. The intent is to return Big Spring Run, PA to a condition similar to that of pre-European settlement. The restoration occurred in fall of 2011 in which 1500 m³ of legacy sediment were removed to restore 1000 m of stream. Our study focuses on the pre-restoration (spring/summer 2010, 2011) and post-restoration (spring/summer 2012) status of amphibian populations. We captured salamanders in each of the three branches being restored (Main, West, and East) using litterbags and kick nets in 2010 and additionally used dip nets and manual capture in 2011. In 2011, we also sampled Kennel branch, a segment that is not part of the restoration and thus serves as a control. To identify the presence of frog species at Big Spring Run, audio recordings were daily collected for 30 minute intervals at dusk during the spring and early summer and were analyzed using the program SongScope. We are using identical survey protocols in 2012 as were used in 2011. 

Results/Conclusions

The salamanders Eurycea bislineata, Pseudotriton ruber, and Desmognathus fuscus were detected, with E. bislineata comprising 97.5% of individuals caught over the two years. The dip net method yielded the most salamanders, but variation existed between the species caught and the capture method. For example, P. ruber was only caught using the litter bag technique. Salamander abundance was consistently lower in the East branch regardless of year or technique. The only adult salamanders were captured in Kennel branch. Our analysis of audio recordings did not reveal any positive identification of the seven species of frogs tested. Salamanders were fairly common in the pre-restored stream, but frogs were not. We are continuing to collect data to determine how frog and salamanders respond to the stream restoration.  Our study, along with the other ones being conducted at Big Spring Run, provides evidence as to the effectiveness of removing legacy sediment as a stream restoration technique. In particular, we determine if it improves habitat quality of amphibian populations in agricultural landscapes.