GIS mapping comparison illustrates how ponds with beavers had 9 times more open water, even during severe drought – beavers may be important natural partners in wetlands restoration.
Beavers and human beings have some things in common. They’re big on land disturbance. It’s a kind of obsession for both.
This presents challenges in the oil sands where beaver tend to want to disturb installations and infrastructures that humans already disturbed – and vice versa. So, in 2009 CEMA – Cumulative Effects Management Association funded an independent research project by Dr. Glynnis Hood, Associate Professor of Environmental Science & Studies at the University of Alberta’s Augustana Campus. The objective was to complete an extensive review of scientific and unpublished literature to determine the potential effects of varying river flows on habitat of semi-aquatic mammals.
CEMA is the oil sands regional environmental stakeholder group charged with gathering and identifying cumulative elements and assessing mitigating factors related to oil sands development on the environment. Dr. Hood’s report findings were recently presented at a public forum at the University of Alberta’s Calgary Centre, to an audience of alumni and interested members of the public.
Dr. Hood is the author of the recently released book entitled “The Beaver Manifesto” She shared some of the aspects of that human-animal conflict research data as well her CEMA report.
Her focus in the CEMA report is related to potential increased water withdrawals from the Athabasca River, used for industrial processing and separation of oil from the bituminous sandy soil. There are several water-users on the river, including municipalities, agriculture, a number of pulp and paper mills, as well as proliferating oil sands operations.
Over the past few years, oil sands operators have improved their processing capacities and technologies so that some 85% of water withdrawn from the river is re-used; Alberta provincial environmental laws also set caps on industrial water withdrawals during seasonal low flow periods. Oil sands operators have established on-site water reserves for such times. However, there is still much to learn about how water withdrawals affect semi-aquatic mammals (muskrats, beavers, mink and river otters), especially in winter.
Beavers have an amazing ability to create massive impoundments that can offer massive water recharging to wetlands and ground water, equivalent to that of a 200 year flood. As some 65% of the oil sands region is made up of wetlands, the role of the beaver in ultimate reclamation will be invaluable. However, that also requires that beaver populations be maintained and human-beaver conflicts reduced.
Likewise, based on research, it appears that a symbiotic relationship exists between other small aquatic mammals such as river otters, mink and muskrat – so Dr. Hood’s work touched on all four.
To gain historical perspective, Dr. Hood, met with dozens of local elders and trappers and reviewed hundreds of pages of diaries and documents dating back to the early fur trade in the 1700’s. CEMA’s interest in muskrats was related to the animal’s importance to First Nation communities.
According to the recent testimony of trappers, historically it was possible to trap 300 muskrat a day from various locations; some people told of having to rent two float planes to fly out their furs. Even with such an astonishing ratio of trapping, muskrat populations were vibrant.
Not so the beaver. It was surprising to learn that by the 1940s, the beaver had all been trapped out of the Wood Buffalo park region and had to be reintroduced in 1948. Once reintroduced, they thrived and repopulated quickly as lifestyles changed and trapping declined.
A major concern to oil sands operators and environmentalists are issues related to water volume and flows and seasonal variations in the Peace-Athabasca Delta. Dr. Hood presented visual evidence of the devastating impact of the Bennett Dam (that began operations in late 1960s on the Peace River) which drastically reduced water levels throughout the delta.
None-the-less, the Athabasca and Peace Rivers are an extraordinary powerhouse. The Athabasca’s mean annual discharge reach some 20,860,000 dam3 at Fort McMurray and 68,200,000 dam3 for the Peace at Peace Point. This is many times that of any other river in Alberta where urban, industrial and agricultural withdrawals are substantially more than that of the oil sands in the north. Fast growing cities like Calgary in south are situated on the edge of the desert-like Palliser Triangle, and subject to severe drought and oversubscription.
However, there are concerns related to the expanding oil sands developments that center around water withdrawals -specifically in winter.
Dr. Hood explained that small river mammals, particularly beaver, create winter reserve caches of food under the water in fall. Their lodges have at least two under water entrances, which allow them free access to swim out and access their food reserves, under the winter ice pack. However, if unrestricted industrial water withdrawals occur which greatly lower the below-ice winter water levels, the beaver’s food caches may be frozen in or their lodge entries may become blocked by ice. This can also be caused by seasonal events like sudden melts/freezes or dam flow restrictions.
If the beaver succeeds in escaping its iced-in lodges, it must surface to search for alternate food. Beavers become easy prey for predators once on the ice. These factors can dramatically reduce the populations of all small aquatic mammals.
Dr. Hood noted that winter water withdrawals from rivers in large urban centers have the same impact.
Consequently, appropriate management of winter water withdrawals, including considering natural weather changes, are key to managing oil sands environmental impact.
Likewise, in terms of ultimate reclamation, beaver populations will be important helpers. Dr. Hood did a GIS mapping comparison of over a decade of air photos in east-central Alberta. Ponds that had beaver populations exhibited 9 times more open water, and this was true even in severe drought periods of 1950 and 2002 (a record dry year). In 2002, beaver ponds had 60% more water, than those same ponds had in 1950 when there was more precipitation, but no beavers!
Dr. Hood’s work also focuses on reducing beaver-human conflicts. Dr. Hood is working with Alberta Parks to implement- a “pond leveller” – a caged, flexible drainage pipe that runs through the dam in a natural beaver impoundment area, allowing the beaver to maintain a home. Yet when flood water levels reach a height that imperils nearby human enterprises or facilities, the pipe is triggered to draw water and release sufficient water to safely reduce the water level.
Now in the test stages, if successful, this method will allow the beaver to continue living in its chosen region where it will fulfill a natural environmental purpose to replenish the wetlands and recharge the water table, while at the same time, the device will protect human facilities from flooding.
Dr. Hood points out the wisdom and cost-efficiency of such an invention. “It’s about a $600. per device, versus trying to bring a backhoe into a remote, muskeg area for about $200-300. per hour to drain a pond that ultimately you really want to maintain for the health of the regional environment and all eco-systems, not just the beaver.”
By assessing decades of observations of wildlife patterns and combining an intimate understanding of the life cycles and habits of these small aquatic mammals we appreciate their role in the larger ecosystem. Then by applying common hydrological principles with simple, easy-to-maintain inventions like the pond levelers, Dr. Hood’s team is finding that we can ‘leave it to beaver’ to help maintain wetland health and ground water recharge. And humans can work side by side with nature, whether in an oil sands or urban/industrial context.