Meeting Abstract
Beavers construct structurally complex and dynamic damming networks.In many cases, it is difficult to understand the building process of beavers because it happens over many years and satellite imagery does not provide sufficient spatial or temporal resolution to track beaver damming network growth. In mountainous regions snow melt annually washes out the previous year beaver builds. Here, beaver colonies thrive by recapitulating the entire dam building process over a period of three to five months. This provides a unique opportunity to study the building process from “scratch”. We hypothesize that beavers build locally and are driven to do so by hydraulic triggers at the dam scale. We present a study of beaver colony damming network construction in the foothills of the Rocky Mountains in northwestern Montana. Using hydraulic measurements and aerial imagery we observed the construction activities of beaver during their active building season. To observe dam building at high enough spatial and temporal resolution we used a DJI Phantom 4 Pro drone to conduct weekly scans of four sites from May 2018 to August 2018, covering approximately 103 hectares, 13 beaver colonies responsible for the construction of 76 dams over a three month period following snow melt. Using Agisoft Photoscan high resolution orthomosaics were built and then annotated with ArcMap to create shapes files in order to track dam network formation and growth. A beaver damming network contains a multitude of features; including dams, ponds, trails, canals, lodges, and scent mounds. Our results suggest that the initiation of building corresponds to the measured volumetric flow rates at each site. The final damming complex is many times larger than any one individual beaver and likely taking place in many locations simultaneously, suggesting beavers engage in distributed building activities.
