This route is more parsimonious than the route of dispersal generated through interviews.
Since it was determined that there is no relationship between the dates estimated through surveys and dendrochronology, it is not possible to determine how much lag there is from the time when changes in the environment are produced by beavers and the time when people notice this change.
This invasion is causing great damage to the subantarctic forest ecosystems, and it is not known how fast the species is spreading.
There were two types of sampling sites: In areas where beaver dams and/or lodges were found, samples were taken from living trees and stumps within a radius of 20 m from the lodge.
When no beaver lodge or dam was found, we choose randomly a stump and sampled on an approximate 20-m radius from it.
For that purpose, we used the program DIVAGIS (Hijmans et al. To estimate the relationship between the activity of the inhabitants and their success in detecting the presence or absence of beavers, we analysed 62 surveys.
The surveyed people were categorized according to their main activity: owner of a small property (≤5 hectares), worker of a small property, owner of a large property (5 hectares), worker of a large property, and visitor to a large property.