The Spring 2016 Newsletter (1.4 MB) of the Ottawa-Carleton Wildlife Centre has extensive information about London, Ontario’s Beaver protocol, one of its Best Wildlife Management Practices. This is in sharp contrast to the City of Ottawa which remains firmly wedded to trap-and-kill. The Centre sent a copy to all members of Council, along with a sharply worded letter, suggesting that a starting point for better ways would be to make Wildlife and Biodiversity a responsibility of Environment Committee rather than Agricultural and Rural Affairs.
An enduring reference (1.2 MB) to how beavers beneficially affect the landscape remains:
Glynnis A. Hood and Suzanne E. Bayley, “Beaver (Castor canadensis) mitigate the effects
of climate on the area of open water in boreal wetlands in western Canada,” Biological Conservation, 2008.
Abstract:
Shallow open water wetlands provide critical habitat for numerous species, yet they have
become increasingly vulnerable to drought and warming temperatures and are often reduced
in size and depth or disappear during drought.We examined how temperature, precipitation
and beaver (Castor canadensis) activity influenced the area of open water in wetlands over a 54-
year period in the mixed-wood boreal region of east-central Alberta, Canada. This entire glacial
landscape with intermittently connected drainage patterns and shallow wetland lakes
with few streams lost all beaver in the 19th century, with beaver returning to the study area
in 1954.We assessed the area of open water in wetlands using 12 aerial photo mosaics from
1948 to 2002, which covered wet and dry periods, when beaver were absent on the landscape
to a time when they had become well established. The number of active beaver lodges
explained over 80% of the variability in the area of open water during that period. Temperature,
precipitation and climatic variables were much less important than beaver in maintaining
open water areas. In addition, during wet and dry years, the presence of beaver was
associated with a 9-fold increase in open water area when compared to a period when beaver
were absent from those same sites. Thus, beaver have a dramatic influence on the creation
and maintenance of wetlands even during extreme drought. Given the important role of beaver
in wetland preservation and in light of a drying climate in this region, their removal
should be considered a wetland disturbance that should be avoided.