The challenge of beaver dams in Blanding's turtle habitat
Blanding's Turtle (Photo by NCC)
While some people consider them adorable, beavers can cause serious headaches for landowners and municipalities that have to deal with dams on their property. The Nature Conservancy of Canada (NCC) has come to their rescue with a series of awareness workshops.
On November 9, 2018, in Clarendon, Outaouais, a few employees and members of municipal council gathered to attend an information session aimed at proposing alternative solutions to the dismantling of beaver dams. This workshop was the last in a series of six workshops organized by NCC during the year.
Beavers build dams to increase their food resource area and protect themselves from predators. In addition to regulating, filtering and purifying runoff water, these wetlands created by beavers are also useful for other species. They promote nesting and feeding of water birds, and also benefit several types of fish, amphibians, reptiles and even some mammals. A few years ago, a study on the movement of Blanding's turtle, a species designated threatened in Quebec since 2009, revealed that more than 90 per cent of their habitats were ponds that were created, maintained or regulated by beavers.
Beaver dam, Ottawa Valley (Photo by NCC)
Unfortunately, however useful they may be, these dams can give way suddenly, flooding land and infrastructure. This is why they are sometimes destroyed by local residents. As beavers return to build their dam if they find the environment favourable, destroying dams is only effective in the short term. And destroying them is a threat to the survival of Blanding's turtle.
This was explained during the presentation by NCC biologists Milaine Saumur and Caroline Gagné. Alternative development solutions to the dismantling of beaver dams were discussed, including preventive structures designed to protect culverts and the installation of a water level control system upstream of a dam. In the second part of the workshop, the small group went into the field, guided by Jean Fink, biologist at the Centre d'enseignement et de recherche en foresterie de Sainte-Foy inc. (CERFO), to observe a system implemented in the fall of 2018. The demonstration illustrated how this system works and how effective it is.
“We found the presentation to be informative and the preventative measures described to be very logical. We appreciated the approach that was taken, which in our opinion took into consideration both the welfare of many species, but also the rights and concerns of landowners. We will definitely be pursuing some of these techniques in the future,” said Patricia Hobbs, Clarendon's director general.
As this solution is quite expensive (between $3,000 and $6,000), NCC and CERFO can look into obtaining funding for non-urgent projects located in Blanding's turtle habitat area. If the situation is urgent, the guideline is to consult a local expert, such as Éco-odyssée, Solution nature, Gesnat, or wildlife management companies, that will be able to implement interventions adapted to the situation.
Although drawing in participants was not easy — a total of 12 citizens and 33 people from the municipal sector attended the workshops in 2018 — their response was positive, there was interest and questions were raised. “There is still a lot of work to be done to raise awareness, but we hope that the message will find its way,” says Milaine.
After the end of October, it is not advisable to modify water levels because the animals are preparing for hibernation, so we will have to wait a while before these installations can hopefully be set up. In the meantime, however, all participants will receive an information package summarizing the main concepts discussed during the sessions and will be invited to complete a questionnaire this winter, the same one they had completed before the workshop, to test their knowledge, and, as a result, measure the impact of this initiative.