MORPHOLOGICALLY AND TEMPORALLY DIVERSE SUITE OF RIVERBANK FEATURES RELATED TO BEAVER ACTIVITY, NESHAMINY CREEK, PENNSYLVANIA

The North American beaver (Castor canadensis) produced a diverse suite of traces, many with a substantial zoogeomorphic impact along a short (<100 m), highly developed reach of Neshaminy Creek, Langhorne (Bucks County, Pennsylvania). At least six bank burrow openings are located along a 2-3-m high left (north) bank of the stream, with bottom entrances near low-water level. Some burrows lead to small bank huts and mud-reinforced huts on a recently wind-felled trees. A nearby tributary of Core Creek exhibits older signs of beaver activity, with multiple waterlogged chew stumps along a steep slope (up to 42°) adjacent to a bridge abutment (stump height: 23-46 cm; diameter: 4-11 cm). During late 2019 - early 2020, new beaver sign appeared on the south bank between the new and abandoned bridges and included a large hut on top of a terrace (height: 1.5-m; slope: 10-14°) and adjacent fresh chew stumps (height: 29-41 cm; diameter: 6-11 cm). As indicated by partially attached trunks and asymmetric chew surfaces, the majority of the trees were felled toward the stream. Along this highly sensitive riparian system, beaver activity is complemented with temporally persistent sediment reworking by bottom-feeding fish (common carp, white sucker) and several species of large turtles, all of which contribute to complex biogeomorphic cascades, especially at sites of felled trees and logjams.