ustainability of the Canadian renewable resource base is fundamental to the economic well-being of the country. The collapse of the East Coast fisheries is an example of what can happen to a profitable resource-based industry, and if global environmental change scenarios for the 21st century prove to be well founded, more economic shocks are in store for Canadians.

• increased understanding of ecosystem functioning, thus contributing to better management of natural resources;
• improved early warning of undesirable trends in ecosystem behaviour;
• early demonstration of the effectiveness of strategies for long-term management of natural resources.

Some of the priority elements in a Canadian LTERM program are as follows:

Program Continuity
A main recommendation is that the program be long-term (decades to a century). This is because ecological systems often have cycles of many decades. To overcome institutional difficulties with respect to continuity of financial support and security of facilities, it is recommended that long-term institutional and financial support be provided by the Government of Canada, in collaboration with the provinces and the community of Canadian ecologists. Because of the importance of Canada's renewable resource base, it might in fact be desirable to enshrine a Canadian LTERM program in an act of Parliament. A number of groups within Environment Canada are already moving in this direction, and their initiatives should be supported.

Collaboration With Relevant Continental and Global Programs
Canada contains a significant fraction of the earth's land and water surface. Thus Canadian participation in international terrestrial ecological programs, particularly the International Council of Scientific Unions' International Giosphere-Biosphere Program (IGBP)/Global Change and Terrestrial Ecosystems (GCTE) and the United States' Long Term Ecological Research (LTER) and Environmental Monitoring and Assessment Program (EMAP), should be given priority. These programs will be the better with Canadian participation, and they will lead to improved understanding of ecosystem functioning in general, and of the behaviour of Canadian ecological systems in particular.

The Need for a Network of Dedicated LTERM Stations
A network of LTERM stations should be established across Canada, building on existing facilities and programs. Because of the wide variety of ecological conditions across Canada, LTERM sites need to be selected carefully if networking is to be effective. Sites need to show sensitivity to global influences, high specificity to stress-producing factors, and should be representative of larger ecological areas. Each terrestrial LTERM site should contain within its bounds, a small calibrated catchment, providing basic information on hydrological and biogeochemical cycling.

LTERM sites should be established not only in wilderness areas such as national parks, but also in managed and degraded areas. LTERM studies of marine ecosystems should be carried out at least at the level of estuarine, open ocean, coastal and ice-dominated systems. Included also should be terrestrial and marine sites where suburban or industrial development is expected in coming decades, as well as areas already severely degraded.

Spacial Scales from Local to Global
Research programs span spacial scales from local to global. Special issues exist with respect to local patchiness, habitat destruction, and in the case of terrestrial systems, fragmentation and corridor degradation at the landscape level, and major climatic and other stresses at the continental and global scales. There are many interactions between scales, which can only be revealed through networks of stations, remote sensing, and field transects extending hundreds or thousands of kilometres.

Time Scales from Seasons to Centuries
It is recommended that the Canadian LTERM program maintain a time perspective of 50 years or longer. Because unprecedented change is possible in the 21st century, the Panel recommends that the Canadian LTERM give priority to the development of early warning indicators of change.

Key Research Topics

• to study the relationships amongst biodiversity, ecosystem functioning, integrity and sustainability;
• to provide early warning of long-term changes in ecosystems;
• to study ecotones, critical environmental zones and areas undergoing cumulative effects;
• to study habitat destruction and renewal, the effects of corridors and fragmentation, and ecosystem responses to perturbation;
• to undertake long-term controlled experiments, with respect to harvesting methods, manipulation of succession, etc.

Socioeconomic Components of LTERM Programs
To understand the causes of long-term ecological change, socioeconomic factors must be considered. For example, changes in land cover are caused by changes in land and water use (including crops grown, irrigation and fertilizers used, etc.) and changes in the driving socioeconomic forces that result in changes in land-use (e.g. changes in population density, number of timber concessions, market prices, etc.). To provide early warning of a possible loss in ecosystem integrity due to the pressure of land-use changes, the relevant socioeconomic factors must be included in LTERM models and monitoring programs.

An Integrated Approach to Ecosystem Monitoring
Each ecosystem should be studied from as many different perspectives as possible, including hydrologic cycling, biogeochemical cycling of carbon and other substances through the ecosystem, food webs, overall energetics, geomorphology and soils, population dynamics. These perspectives should be applied in an integrated fashion rather than applied separately as is frequently done. This would help in deciding monitoring priorities.

Implementation
The Panel recommends that Environment Canada be asked to be the lead agency for an LTERM Program in Canada. An LTERM standing Committee of the CGCP, composed of a non-governmental group of experts should be established to play an advisory role.