Diet and lake size are the main drivers of the territorial occupation dynamics of North American beaver

Abstract

Beavers, as ecosystem engineers, create crucial wetlands and habitats for other species, altering the structure and function of the surrounding forests and affecting human infrastructure. However, despite these significant economic and ecological implications, the spatiotemporal patterns of beaver feeding strategies remain understudied. This study aimed to evaluate how forest stand type, lake size, and diet influence beaver territorial occupation in eastern Canada. We used a dendroecological approach to measure beaver occupation time and maximum browsing distance around 61 lakes. Around each beaver lodge, we established 1 m² plots along three transects in which we measured distance of browsing from shore and counted annual rings on coppices resulting from beaver presence. PERMANOVA revealed that both maximum browsing distance ( p = 0.003) and temporal occupation ( p = 0.006) differed significantly across lake size categories. The type of forest stand had no impact on beaver dynamics. Stable isotope analysis (δ13C and δ15N) of beaver carcasses collected from local trappers showed that the beavers’ diet included the consumption of conifer trees and a seasonal shift in food consumption. We found that lakes ranging from 4 to 20 ha were optimal for beavers, as this lake size mattered more than the availability of specific food sources. Beavers exhibited high adaptation skills by using different plant species depending on the season to maximize resource availability and energy cost trade-off. Understanding the factors involved in beaver territorial occupation dynamics is crucial for land managers and conservationists to effectively incorporate this species into forest management plans and mitigate beaver–human conflicts.