PDF format (1353 kb)

• Acknowledgements
• Preface
• Highlights
• 1  Introduction
• 2  The Boreal Shield Ecozone
• 3  Environmental Stresses from Within
• 4  Environmental Stresses from Outside
• 5  Selected Indicators of Change
• 6  Prognosis for a Healthy Ecozone
• 7  Conclusion

Edited by:

Natty Urquizo
Rainmakers Environmental Group

Jamie Bastedo
Cygnus Environmental Consulting

Tom Brydges
formerly EMAN Coordinating Office
Environment Canada

Harvey Shear
Ontario Region
Environment Canada

Acknowledgements

Contributors
• Allan, Rod J., National Water Research Institute, Canada Centre for Inland Waters, Environment Canada, Burlington, Ontario
• Bastedo, Jamie, Cygnus Environmental Consulting, Yellowknife, N.W.T.
• Brydges, Tom, formerly EMAN Coordinating Office, Environment Canada, Burlington, Ontario
• Hall, Peter, Canadian Forest Service, Natural Resources Canada, Ottawa, Ontario
• Hendrickson, Ole, Canadian Forest Service, Natural Resources Canada, Ottawa, Ontario
• Hopkin, Anthony, Canadian Forest Service, Natural Resources Canada, Sault Ste. Marie, Ontario
• Rubec, Clayton, Canadian Wildlife Service, Environment Canada, Ottawa, Ontario
• Shearer, John, Experimental Lakes Area Operations, Fisheries and Oceans Canada, Winnipeg, Manitoba
• Stocks, Brian J., Canadian Forest Service, Natural Resources Canada, Sault Ste. Marie, Ontario
• Urquizo, Natty, Rainmakers Environmental Group, Niagara-on-the-Lake, Ontario
• Waite, Don, Prairie and Northern Region, Environment Canada, Regina, Saskatchewan
• Wood, John A., Ecological Research Division, Prairie and Northern Region, Environment Canada, Regina, Saskatchewan

Reviewers
• Bergeron, Yves, Boreal Shield (Quebec) Ecological Science Cooperative, Lac Duparquet, Quebec
• Cole, Bill, Government of Ontario, Boreal Shield (Ontario) Ecological Science Cooperative, Swan Lake, Ontario
• DeKimpe, Christian, Natural Resources, Agriculture and Agri-Food Canada, Ottawa, Ontario
• Dillon, Peter, Ontario Ministry of Environment and Energy, Dorset Environmental Science Centre, Dorset, Ontario
• Eros, Susan, Resource Conservation, Environmental Conservation Branch, Prairie and Northern Region, Environment Canada, Edmonton
• Evans, Doug, Environmental and Resources Studies, Trent University, Peterborough, Ontario
• Gagnon, Réjean, Université du Québec à Chicoutimi, Chicoutimi, Quebec
• Gunn, John, Co-operative Freshwater Ecology Unit, Ontario Ministry of Natural Resources, Department of Biology, Laurentian University, Sudbury, Ontario
• Hirvonen, Harry, Canadian Forest Service, Natural Resources Canada, Ottawa, Ontario
• Ironside, Gary, Indicators and Assessment Office, Environment Canada, Ottawa, Ontario
• Jeffries, Dean, Atmospheric Contaminant Impacts, Environment Canada, Burlington, Ontario
• Johnston, Vicky, Canadian Wildlife Service, Environment Canada, Yellowknife, N.W.T.
• Kronberg, Barbara, Lakehead University, Thunder Bay, Ontario
• Langford, Lynda, Ecosystem Management Special Project Manager, Saskatchewan Environment and Resource Management, Regina, Saskatchewan
• LeHénaff, Annick, Indicators and Assessment Office, Environment Canada, Ottawa, Ontario
• Maarouf, Abdel, Climate and Atmospheric Research Directorate, Environment Canada, Downsview, Ontario
• McAfee, Brenda, Canadian Forest Service, Natural Resources Canada, Ottawa, Ontario
• Piche, E., Environmental Monitoring and Reporting Branch, Ontario Ministry of the Environment, Toronto, Ontario
• Pinel-Alloul, Bernadette, University of Montreal, Montreal, Quebec
• Quaile, Geoffrey, Environmental Advisor, Grand Council of the Crees of Eeyou Istchee, Quebec
• Savard, Sylvain, Canadian Forest Service, Natural Resources Canada, Ottawa, Ontario
• Savidge, Rodney A., Faculty of Forestry and Environmental Management, University of New Brunswick, Fredericton, New Brunswick
• Schindler, David, University of Alberta, Edmonton, Alberta
• Snucins, Ed, Co-operative Freshwater Ecology Unit, Ontario Ministry of Natural Resources, Department of Biology, Laurentian University, Sudbury, Ontario
• Streich, Laurie, Manitoba Environment, Winnipeg, Manitoba
• Van dijk, Albert, La Mauricie National Park, Parks Canada Agency, Canadian Heritage, St-Mathieu du Parc, Quebec

Production
• Crocodile Communications Inc., Ottawa, Ontario: design services and electronic page layout
• Duggan, Doug, Indicators and Assessment Office, Environment Canada, Ottawa, Ontario: preparation of most figures
• Ironside, Gary, Indicators and Assessment Office, Environment Canada, Ottawa, Ontario: coordination of final editing and production
• Sheffer, Marla, Scientific Editing, Orleans, Ontario: copy editing

Preface

The Canadian environment, source of so much of the country’s natural wealth, is under stress. Some of these stresses come from within, caused by forestry, mining, agriculture, hydroelectric generation, road construction, and other activities. Others come from outside the ecozone, often arising far away — climate change, stratospheric ozone depletion, acid precipitation, and the longrange air transport of pollutants, for example.

While some of these stresses, such as forest harvesting, cause immediate and obvious changes, others, such as the changing atmosphere, can result in long-term subtle ecosystem responses. Consequently, multiyear, multidisciplinary studies, supported by research and experiments, are needed to define ecosystem responses to these stresses and to design satisfactory environmental protection programs and resource management policies.

An urgent challenge now facing the scientific community is the need to mobilize efforts to understand and report on environmental changes in ways that contribute to improved decisionmaking. This is one of the main purposes of the Ecological Monitoring and Assessment Network, known as EMAN. The activities of EMAN are administered by the EMAN Coordinating Office of Environment Canada, in Burlington, Ontario. The EMAN Coordinating Office promotes the linking of ecological studies across Canada through workshops and national meetings. Preparing a directory of sites, describing their scientific studies, providing an inventory of researchers, and compiling bibliographies and data sets are among the many ways the EMAN Coordinating Office makes links with the wider world where land and water use decisions are made.

But the rate and magnitude of environmental changes we are now observing dictate that we must do much more. These organizational aspects are not sufficient to make EMAN as useful and as responsive to reporting on ecological concerns as it should be. While these projects were quite successful, they have yet to be fully applied in finding solutions to the multiple stresses now affecting Canada’s rapidly changing environment.

In 1997, we initiated a pilot project to further develop the concepts and objectives of EMAN by contributing information from a number of EMAN sites to a multidisciplinary assessment report. We decided that the boundaries of this project should be defined by one of Canada’s 15 terrestrial ecozones. We chose the Boreal Shield ecozone for the pilot project, as it is of great economic importance to Canada and is subjected to all of the major stresses outlined above. There are 22 EMAN sites within this ecozone, some of which have the longest multidisciplinary monitoring data sets in Canada.

The Boreal Shield also represents an opportunity to study a number of stresses by comparing results at different sites. For example, acid rain affects the central part of this ecozone, with little effect in the extreme eastern and western areas, whereas increased ultraviolet-B radiation and atmospheric carbon dioxide concentrations may be more uniform across the ecozone. As well, average annual air temperature is increasing in the west and slightly decreasing in the east.

As a pilot project, this report may not be as complete and as detailed as possible, but, with the willing support of many scientists, we have assembled a substantial amount of information documenting the multiple stresses that now impinge upon the Boreal Shield ecozone.

Highlights

The Boreal Shield is Canada’s largest ecozone, covering almost 20% of its land mass, containing 43% of its commercial forestland, and accounting for 22% of the country’s freshwater surface area. The ecozone has a gross domestic product of almost $50 billion. Major contributors to the economy include hydroelectric generation ($16 billion), mining ($6 billion), and forestry ($5.85 billion from pulp and paper). The Boreal Shield is home to three million people and provides 15% of Canada’s resource-based employment.

This assessment reviews findings and highlights current trends relating to environmental stresses on the Boreal Shield ecozone, provides direction to strengthen national programs aimed at addressing environmental concerns and developing remedial and preventative strategies, and, finally, focuses on the links of science with policy.

Ecosystem changes — links to stresses from within

Forestry
• Most indicators point to a net increase in wood harvested in the Boreal Shield over the past few years. The 1990s have also witnessed a rapid northward expansion of forestry-related activities.

• Clearcutting accounts for 90% of the 400 000 ha harvested annually in the Boreal Shield. The potential environmental impacts of clearcutting are well documented and include:

• reduced biodiversity
• loss or alteration of wildlife habitat
• soil modification
• reduced water quality

Mining
• The Boreal Shield ecozone supplies 75% of Canada’s iron, nickel, copper, gold, and silver.
• Northern Saskatchewan is the largest producer of uranium in the world, accounting for 34% of world production. Three new uranium projects are currently under development, and a fourth is expected to begin early in the next century.
• The primary impact of mines in the Boreal Shield is on aquatic biodiversity, caused by the discharge of mine effluents into water. Environmental problems created by abandoned mines also represent a major long-term hazard for the general health of the ecozone.

Hydroelectricity
• Canada is the largest producer of hydroelectricity in the world, accounting for approximately 15% of the world’s total production. Thirty-nine per cent of Canada’s hydroelectric capacity is located on rivers arising in or flowing through the Boreal Shield.

• Hydroelectric development has altered 85% of the drainage basins contained in whole or in part in the Boreal Shield — 77% contain major dams, 25% have major reservoirs, and 33% have rivers whose flow has been either augmented or diminished by water transfers.

• Impacts from hydroelectric development include:

• loss of terrestrial habitats through dam construction and reservoir impoundment
• shoreline erosion
• wildlife and habitat disturbances associated with transmission corridors
• altered competitive and predatory aquatic regimes due to increased water volume
• increased turbidity
• mercury release from the flooding of organic matter by reservoirs
• release of carbon dioxide and methane from extensive flooding of land

Additional land uses
• Widespread cottage development on Boreal Shield lakes has led to significant public concern about the eutrophication of recreational lakes. Another issue of concern is the removal of shoreline vegetation by cottage owners, resulting in local macrophyte population declines and disruptions to aquatic food chains.
• Although the Boreal Shield is the largest of Canada’s 15 terrestrial ecozones, it has one of the lowest proportions of land — less than 3% — dedicated to protected areas in which all forms of industrial activity are prohibited.

Ecosystem changes — links to stresses from outside

Climate change
• Atmospheric models predict that Boreal Shield forests and wetlands are likely to be highly vulnerable to the effects of global warming. Small increases in temperature may give rise to large increases in biological activity, particularly in rates of plant growth and litter decomposition.

• Changes in lakes and rivers in the Boreal Shield have been recorded in response to changes in climate. At Ontario’s Experimental Lakes Area, a temperature increase of 1.6°C and a 40% drop in precipitation were observed from 1970 to 1990, with the following results:

• shorter ice cover periods for lakes
• a nearly 50% increase in evapotranspiration
• decreased dissolved organic carbon (DOC) and phosphorus in lakes
• increased transparency, resulting in deeper penetration of ultraviolet-B (UV-B) radiation
• decreased phytoplankton abundance in lakes with reduced phosphorus

Acid precipitation
• Many fish and invertebrate populations from the Boreal Shield region have been lost as a result of acid precipitation. The poorly buffered lakes of the eastern half of the ecozone are particularly sensitive to acidification.

• Increased acidity is linked to high concentrations of mercury, cadmium, and lead in fish and can cause a loss of DOC in surface waters.

• The role of acid deposition in contributing to Boreal Shield forest declines has been widely studied. Some well-documented effects include:

• decreased net photosynthesis and nutrient uptake
• impaired germination
• reduced frost hardiness
• damage to protective leaves and needle cuticles
• decreased ability to cope with other stressors, such as climate warming, drought, insect outbreaks, and disease

Ultraviolet-B (UV-B) radiation
• Very little is known about trends in UV-B radiation in the Boreal Shield ecozone, as the stressor is only beginning to be studied. Spectral measurements of UV-B radiation between 1989 and 1993 in Toronto, Ontario, just south of Boreal Shield latitudes, indicated that the intensity of light at wavelengths near 300 nm had increased by 35% per year in winter and 7% per year in summer. The trend at wavelengths between 320 and 325 nm, however, was essentially zero.
• Reduced tree vigour, reduced photosynthetic activity, sun scalding, and premature aging of needles are among the multiple impacts of rising UV-B radiation on coniferous trees.
• Stream invertebrates may be particularly sensitive to UV-B radiation, but even deepwater or bottom-dwelling organisms may experience adverse effects when they enter near-surface waters.

Long-range transport of pollutants
• Significant amounts of organochlorine pesticides are deposited into Boreal Shield lakes from long-range transport. While these quantities are not acutely toxic, their chronic effects are unknown. Studies suggest that persistent organic pollutants are accumulating in certain tissues of Boreal Shield invertebrates, fish, and higher vertebrates and may, over time, contribute to population declines and ecosystem malfunctions.

Indicators of ecosystem change

Disturbances
Forest fires
• Fire is a natural and dominant disturbance in the Boreal Shield ecozone. Fire is generally required for the adequate regeneration of most tree species.
• The annual area burned varies from 0.7 to 7 million hectares, averaging 2.9 million hectares annually. Fires are larger and occur with greater frequency in the Boreal Shield than in any other forested region of the country. Records reveal an upward trend in both fire occurrence and area burned in recent years.
• With present climate warming trends, larger fires are anticipated in northern parts of the ecozone. This could create undesired shifts in forest composition and age structure and negatively impact the global carbon budget.

Insects
• Insect outbreaks in forests have generally increased in area and duration over the past 25 years, possibly due to more intensive harvesting practices and fire suppression. The proportion of tree mortality due to insects is 1.5 times that due to wildfire and is equivalent to one-third of the annual harvest volume.
• The spruce budworm infestation that lasted from 1966 to 1996 resulted in 8.3 million hectares of balsam fir and white spruce mortality in Ontario, mostly in the Boreal Shield.
• The jack pine budworm range has been expanding eastward over the last 30 years, with outbreaks detected over large areas in central and eastern Ontario.The forest tent caterpillar, which is the most significant defoliator of hardwood trees in the Boreal Shield ecozone, recently defoliated 9.5 million hectares of birch and poplar forests in Ontario.

Contaminants
• Numerous fish species throughout Ontario and Manitoba contain dangerously high levels of mercury in their tissues, resulting in warnings regarding the amounts of fish that can be safely consumed by humans.
• Mercury contamination is a particular concern to Aboriginal people in this ecozone, many of whom give fish a central place in their diet.

Biodiversity
• The spread of exotic species that are harmful to native tree species is a growing concern for Boreal Shield forest managers.

• The balsam woolly adelgid, an insect pest, is causing serious damage to balsam fir stands in Newfoundland, where it was accidentally introduced in the 1920s or 1930s.
• The white pine blister rust, a tree disease caused by an introduced fungus, is also damaging trees in the Boreal Shield, particularly in southern parts of the ecozone.
• In Manitoba, Ontario, and Quebec, purple loosestrife, a flowering plant, is a serious concern as it clogs streams and competes with native cattails and other aquatic plants important for wildlife.

Where do we go from here?

Resource management
• The National Forest Strategy, unveiled in the spring of 1998, provides a framework that will guide the policies and actions of the forest community over the course of the next few years in order to make the goal of sustainable forestry a reality. There will be a need for on-theground monitoring to determine how effectively its objectives are being met.

• Mine management will be improved through the development and implementation of a cooperative national environmental protection framework. This would include a revised federal effluent regulation, site-specific requirements, and environmental effects monitoring to provide information on the effectiveness of environmental protection measures.

• All provincial hydroelectric utilities and governments must give greater priority to ecosystem monitoring, hindsight assessments, and baseline research in order to answer the many environmental questions surrounding large-scale hydroelectric projects in the Boreal Shield.

• There is a growing public call for more coordinated management of Boreal Shield wetlands. To help address such concerns, the Federal Cabinet formally adopted the Federal Policy on Wetland Conservation in December 1991. The Policy was enhanced in 1996 with Guidelines for Federal Land Managers and has been complemented by provincial wetland policies.

• Additional studies are needed to better understand the full environmental impacts of recreational development and tourism in the Boreal Shield. Recent planning and policy advances in Ontario provide for improved site assessments and pollution controls for cottage developments.

• While the need to complete protected area networks in the Boreal Shield ecozone is well recognized, mounting resource development pressures are slowing movement towards this goal. Integrating an expanded protected area network with environmentally progressive land management practices is key to conserving biodiversity on an ecozone-wide scale.

Environmental monitoring
• Environmental monitoring programs in the Boreal Shield have shed much light on the severity of impacts of acidification on both terrestrial and aquatic ecosystems, the complexity of their interactions, and the dynamics of ecosystem recovery. Continued monitoring will be essential to gauge the effectiveness of future regulatory controls and to address the many unknowns raised by ongoing research.

• UV-B exposure is one of the most complex and least understood stressors now influencing the Boreal Shield ecozone. Continued monitoring of stratospheric ozone and incident UV-B radiation, and associated impacts on Boreal Shield ecosystems, will enable scientists and decision-makers to better understand the full significance of this stressor and determine how best to respond.

• The many unknowns and growing international concern regarding the long-range transport of persistent organic pollutants and heavy metals make enhanced monitoring of airborne contaminants imperative.

• Monitoring of the many indicators of ecosystem health — the severity and extent of insect outbreaks, mercury levels, and leopard frog numbers, for example — is essential to keep a pulse on the environmental health of the Boreal Shield ecozone.