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In this paper, a review of Indigenous engagement in renewable energy projects is conducted and the main elements of energy partnerships between stakeholders and Indigenous partners are discussed. In recent years, Canada has witnessed more significant Indigenous involvement in economic and energy development projects than ever before. For large-scale energy partnerships, the focus is on engagement, financial capital, community buy-in (readiness, and entrepreneurial and business skills), and benefits-sharing with community partners. Equity-ownership, reconciliation, and self-determination intersect with and impact the benefits and sustainability of energy projects, as they are interrelated in the framework of most energy partnerships. This paper illustrates policy disconnects in connection with partnership-making, social outcomes, and decision-making among Indigenous communities. Furthermore, findings from relevant literature explore the nuanced discourse on social implications and capacity challenges that interlink with climate adaptation and reconciliation when promoting large-scale renewable energy partnerships with Indigenous communities. Through a systematic review and a meta-analysis of the literature, we found 80 relevant studies during the screening process, of which 33 were selected for the synthesis. Findings demonstrate that the Crown, energy companies, and community partners need to coordinate and collaborate closely to achieve energy security and sustainable renewable energy. The review suggests that Indigenous engagement in energy partnerships supports positive outcomes for social development and environmental protection among Indigenous communities. The literature suggests that when government and industry mentor in the project implementation process, important positive impacts on energy transitions, and self-sufficiency can be realized. [ABSTRACT FROM AUTHOR]

Similar to many freshwater ecosystems, the Laurentian Great Lakes of North America have undergone numerous anthropogenic stressors resulting in considerable loss of biodiversity and habitat. Among Great Lakes fishes, the coregonine sub-family has endured the most extensive declines, including extinction of several species (Coregonus johannae, C. alpenae, and C. kiyi orientalis) and at least 10 instances of local extirpations of other species (C. nigripinnis, C. reighardi, C. zenithicus, C. hoyi, and C. artedi) across all 5 lakes, much of which occurred prior to the 1960s owing to overfishing, interactions with non-indigenous species, and habitat loss. Despite these declines, no federal-, provincial-, or state-mandated actions were ever implemented to conserve coregonine diversity, potentially because so much of the coregonine declines occurred prior to the enactment of federal conservation legislation. Possible explanations for inaction since enactment of that legislation include insufficient data on biological vulnerability or threats, unresolved taxonomy, and limited support from the fishery management agencies and their stakeholders prior to the 2000s. In recent decades, however, several fishery management agencies have undertaken efforts to re-introduce coregonine diversity. These efforts helped lead to development of a science-based framework to restore coregonines that was universally endorsed by fishery managers representing eight U.S. states, four U.S. tribal organizations, and the province of ON, Canada, in May 2018. The basin-wide framework is based on principles of conservation biology and adaptive management. We describe details of its key steps, including planning, restoring, and evaluating, while also describing recent implementation efforts to develop methods, improve available resources, and enhance coordination across the basin. Although our paper describes a regional effort to restore native coregonines, our adaptive-management approach could be used by other multi-agency stakeholders seeking to conserve or restore native fishes. [ABSTRACT FROM AUTHOR]

Much of Canada's industrial sector is driven by natural resources and relies heavily on provisioning services supplied by the boreal zone. However, the sometimes intensive processes used by resource-based industries and their associated infrastructure have significantly altered the region, creating concerns over the future socio-ecological health of the boreal zone. Addressing these concerns will require industries reliant on natural resources from the boreal zone to innovate their processes, management, and infrastructure to improve extraction efficiency while contributing to society's increasing expectations related to sustainability. Here, we explore past, current, and future trends in industrial innovation and infrastructure in the boreal zone for forestry, mining, pulp and paper, oil and gas, and renewable sources of power generation. We assess the role of innovation on the future socio-ecological state of the boreal zone by considering interactions between innovation in industry and infrastructure and other key drivers of change in the boreal, such as atmospheric changes, changing demands for nonprovisioning and provisioning ecosystem services, governance, and demographics and social values. We present future scenarios highlighting three divergent trajectories of change in boreal ecosystems based on past and current states of innovation in industry and infrastructure. We suggest that minimizing impacts of natural resource extraction activities in the boreal zone will only be possible through innovation directly focused on reducing the human footprint on the landscape. Innovation in the information technology sector related to process, management, and end products within these industries and placing greater emphasis on cross-sectoral collaboration will be key to achieving this goal. [ABSTRACT FROM AUTHOR]

Traditionally, forest management has focused on forestry-related practices whereas other industries have been managed separately. Forest management requires the integration of all natural resource development activities, along with other anthropogenic and natural forest disturbances (e.g., climate change, pollution, wildfire, pest disturbance) to understand how human activities can change forested ecosystems. The term cumulative effects has been used to describe these attempts to integrate all disturbances to develop an understanding of past, current, and future impacts on environmental, social, and economic components of the system. In this review, we focus on the science required to understand the past, current, and future impacts of the cumulative effects of anthropogenic and natural disturbances on forested ecosystems or their components. We have primarily focused on the terrestrial system with an emphasis on northern forests in Canada. Our paper is not intended to be a comprehensive review of all cumulative effects science but a synthesis of the challenges and approaches currently being used. Central repositories were identified as an approach to deal with issues of availability of remotely sensed data on anthropogenic and natural disturbances. Data integration projects, open data, and well-designed large-scale data collection efforts are needed to provide sufficient data on environmental responses to cumulative effects. As well, large-scale integrated, modularized ecosystem models are needed to bring stressor and environmental response data together to explore responses to, and interactions between, multiple stressors to project these effects into the future and to identify future data collection needs. [ABSTRACT FROM AUTHOR]

Industrial development within Canada's boreal zone has increased in recent decades. Forest management activities, pulp and paper operations, electric power generation, mining, conventional oil and gas extraction, nonconventional oil sand development, and peat mining occur throughout the boreal zone with varying impacts on water resources. We review impacts of these industries on surface water, groundwater, and wetlands recognizing that heterogeneity in the dominance of different hydrologic processes (i.e., precipitation, evapotranspiration, groundwater recharge, and runoff generation) across the boreal zone influences the degree of impacts on water resources. Through the application of best management practices, forest certification programs, and science-based guidelines, timber, pulp and paper, and peat industries have reduced their impacts on water resources, although uncertainties remain about long-term recovery following disturbance. Hydroelectric power developments have moved toward reducing reservoir size and creating more natural flow regimes, although impacts of aging infrastructure and dam decommissioning is largely unknown. Mineral and metal mining industries have improved regulation and practices, but the legacy of abandoned mines across the boreal zone still presents an ongoing risk to water resources. Oil and gas industries, including non-conventional resources such as oil sands, is one of the largest industrial users of water and, while significant progress has been made in reducing water use, more work is needed to ensure the protection of water resources. All industries contribute to atmospheric deposition of pollutants that may eventually be released to downstream waters. Although most industrial sectors strive to improve their environmental performance with regards to water resources, disruptions to natural flow regimes and risks of degraded water quality exist at local to regional scales in the boreal zone. Addressing the emerging challenge of managing the expanding, intensifying, and cumulative effects of industries in conjunction with other stressors, such as climate change and atmospheric pollution, across the landscape will aid in preserving Canada's rich endowment of water resources. [ABSTRACT FROM AUTHOR]

This paper identifies and characterizes current knowledge on climate change impacts, adaptation, and vulnerability for Canada's northern coastline, outlining key research gaps. Warming temperatures and increased precipitation have been documented across the northern coast, with the rate of sea ice decline ranging from 2.9% to 10.4% per decade. Storm intensity and frequency is increasing, and permafrost is warming across the region. Many of these changes are projected to accelerate in the future, with in excess of 8 °C warming in winter possible under a high-emission scenario by 2081-2100. Vulnerability to these changes differs by region and community, a function of geographic location, nature of climate change impacts, and human factors. Capacity to manage climate change is high in some sectors, such as subsistence harvesting, but is being undermined by long-term societal changes. In other sectors, such as infrastructure and transportation, limitations in climate risk management capacity result in continuing high vulnerabilities. There is evidence that adaptation is taking place in response to experienced and projected impacts, although readiness for adaptation is challenged by limited resources, institutional capacity, and a need for support for adaptation across levels of government. Priority areas for future research include ( i) expanding the sectoral and geographic focus of understanding on climate change impacts, adaptation, and vulnerability; ( ii) integrating climatic and socio-economic projections into vulnerability and adaptation assessments; ( iii) developing an evidence base on adaptation options; and ( iv) monitoring and evaluating the effectiveness of adaptation support. Cross-cutting themes for advancing climate change impacts, adaptation, and vulnerability research on the north coast more broadly include the need for greater emphasis on interdisciplinary approaches and cross-cultural collaborations, support for decision-orientated research, and focus on effective knowledge mobilization. [ABSTRACT FROM AUTHOR]

The boreal zone and its ecosystems provide numerous provisioning, regulating, cultural, and supporting services. Because of its resources and its hydroelectric potential, Canada's boreal zone is important to the country's resource-based economy. The region presently occupied by Canada's boreal zone has experienced dramatic changes during the past 3 million years as the climate cooled and repeated glaciations affected both the biota and the landscape. For about the past 7000 years, climate, fire, insects, diseases, and their interactions have been the most important natural drivers of boreal ecosystem dynamics, including rejuvenation, biogeochemical cycling, maintenance of productivity, and landscape variability. Layered upon natural drivers are changes increasingly caused by people and development and those related to human-caused climate change. Effects of these agents vary spatially and temporally, and, as global population increases, the demands and impacts on ecosystems will likely increase. Understanding how humans directly affect terrestrial and aquatic ecosystems in Canada's boreal zone and how these effects and actions interact with natural disturbance agents is a prerequisite for informed and adaptive decisions about management of natural resources, while maintaining the economy and environment upon which humans depend. This paper reports on the genesis and present condition of the boreal zone and its ecosystems and sets the context for a detailed scientific investigation in subsequent papers published in this journal on several key aspects: carbon in boreal forests; climate change consequences, adaptation, and mitigation; nutrient and elemental cycling; protected areas; status, impacts, and risks of non-native species; factors affecting sustainable timber harvest levels; terrestrial and aquatic biodiversity; and water and wetland resources. [ABSTRACT FROM AUTHOR]

Cumulative effects assessment (CEA) became an increasingly important component of environmental impact assessment (EIA; or simply environment assessment (EA)) shortly after formal processes for EIA were established in North America in the 1970s. Despite a growing body of literature addressing science requirements of exemplary EIA and CEA, practice remains contested. Our mission in preparing this review was to provide a critical update on progress in scientific developments associated with CEA and also to guide practitioners to a broad selection of the recent relevant peer-reviewed formal literature on CEA. In addition, we point to ways in which guidance for CEA practice could be improved. The study canvassed widely for refereed papers in journals and edited books as far back as 2000. On the matter of key concepts related to CEA, the paper addresses the definition of other activities to be assessed, establishment of time and space bounds, impact thresholds, methods for impact prediction, and stressor-based versus effect-based approaches. Definitions of cumulative effect are reviewed, with encouragement for continued work to elaborate the concept. Contributions from science to CEA practice are identified as follows: retrospective and prospective investigative protocols; basic ecological knowledge; effects knowledge; tools and methods; ecological grounds for threshold establishment; and analytically competent practitioners. We observe that the plethora of CEA frameworks populating the scientific literature offer practitioners helpful ways to think about the CEA process. CEA methods are then reviewed, with specific emphasis on geographic information systems, scenario-building, thresholds, indicators, simulation, and public engagement. Several case examples of CEA in practice are summarized, with the observation that none of the published case studies arises from work done to support CEA that is part of the regulated EIA process. The paper reflects on the role of CEA in project-specific EIA (or project EA) as well as class EA, strategic EA, and regional EA. CEA is needed in all forms of EA, but it seems to be particularly difficult to implement well in project-specific EIAs. Recommendations for improvements in guidance materials for practitioners address definitions, scenarios, analytical methods, collaborative methods, thresholds, knowledge accumulation, accidents and malfunctions, project scale, and knowledge integration. We conclude that competent CEA is a vital requirement for securing the sustainability of valued ecosystems and their components. [ABSTRACT FROM AUTHOR]

Canada's environmental effects monitoring (EEM) program is currently in its fifth cycle of monitoring for the pulp and paper industry and second cycle of monitoring for the metal mining industry. More than 60 different sentinel fish species have been used in the EEM fish population surveys and reproductive impacts have been identified as an issue of concern in the pulp and paper program. A review of the literature was conducted to obtain details of the reproductive biology of each fish species that has been used in EEM studies in Canada. Using available data on seasonal changes in gonadosomatic indices, the seasonal reproductive patterns of Canadian fish species were divided into categories based on reproductive strategy and the timing of initiation of gonadal recrudescence. Recommended sampling times were developed for each reproductive pattern based on periods of temporal stability, minimum variability, and maximum value in gonadosomatic indices within a reproductive cycle. The reproductive strategy, spawning time, spawning temperature, and recommended sampling time were provided for the each sentinel fish species as well as life history characteristics including longevity, age and size at maturity, and mobility. Examination of the fish surveys using small bodied forage species from the EEM pulp and paper program revealed that approximately 72% of these studies were not conducted at the developed recommended sampling times and the magnitude of impacts may be underestimated by failing to sample at the recommended time. [ABSTRACT FROM AUTHOR]

This paper reviews annual government spending on Canadian agriculture that attempts to stabilize and enhance farm incomes. Over the past 5 years, 2/3 of the $3 billion spent on agriculture went into stabilization programs to support farm incomes. However, this level of support raises questions about the environmental consequences of enhanced agricultural production. Environmental impacts from agriculture are well known and addressed in US and EU policies. In contrast, Canadian government expenditures on environmental initiatives in agriculture, as a share of farm income, are more than 10 times smaller than those in the US and the EU. Nonetheless the evidence is that Canadian programs have modest impacts on production, but that chemical and fertilizer input use may be higher than in the absence of the program. One possible course of action is to introduce cross-compliance between program payments and environmental objectives. However, there are no requirements that Canadian producers receiving support comply with environmental standards. While cross-compliance could be considered in the Canadian context, policies that directly target specific environmental issues in agriculture may have greater impact. [ABSTRACT FROM AUTHOR]

This paper aims to be a cursory relative comparison between applications of custom-designed constructed wetland systems for specific water resources protection in Canada and northern China. Comparing constructed wetlands can be difficult and at times misleading; they are custom built to deal with specific target wastewater at specific locations and differ not only in physical shape and dimension, but in vegetation cover, hydraulic retention time, and pollutant loading rates. Treatment efficiencies defined by the Canadian and northern Chinese experience vary considerably. Experience in both countries shows that the majority of effluent values are generally better than those required by discharge standards in Canada and China. Examples provided from both countries demonstrated that plants can play a role in constructed wetland systems and make a difference in treatment efficiency. A review of the available case studies on cold weather treatment in both countries indicates that this technology is feasible in Canada and northern China, although further monitoring data are needed to optimize wetland design and ensure that the effluent quality standards are consistently met. Constructed wetland systems in both countries have an apparent advantage in construction costs, and the costs for treatment and operation and maintenance of these systems are much lower than those of conventional wastewater treatment plants. Land requirements for constructed wetlands present one of the factors most limiting their broader use, especially in China, where land resources are scarce and population density is high. [ABSTRACT FROM AUTHOR]

Much of Canada's terrestrial biodiversity is supported by boreal forests. Natural resource development in boreal forests poses risks to this biodiversity. This paper reviews the scientific literature to assess the effects of natural resource development on terrestrial biodiversity in Canadian boreal forests. We address four questions: (1) To what extent have Canadian boreal forests changed due to natural resource development? (2) How has biodiversity responded to these changes? (3) Will the biodiversity of second-growth forests converge with that of primary boreal forests? (4) Are we losing species from boreal forests? We focus on trees, understory plants, insects, fungi, selected mammals, and songbirds because these groups have been most studied. We review more than 600 studies and found that changes in community composition are prevalent in response to large-scale conversion of forest types, changes in stand structures and age distributions, and altered landscape structure resulting from forest management and habitat loss associated with other developments such as oil and gas, hydroelectric, and mining. The southern boreal forest has been more highly impacted than the north due to more extensive forest management and the cumulative effects of multiple forms of development. There is abundant evidence that most species are not in danger of being extirpated from the boreal forest due to these anthropogenic changes. A few species, including woodland caribou ( Rangifer tarandus) and grizzly bear ( Ursus arctos), have, however, undergone long-term range contractions. Significant gaps in our ability to assess the effects of natural resource development on biodiversity in the boreal zone are the lack of long-term spatial and population data to monitor the impact of forest changes on ecosystems and species. [ABSTRACT FROM AUTHOR]

There are concerns about the effect of increasing resource extraction and other human activities on the soils and vegetation of the boreal zone. The review covers published papers between 1974 and 2012 to assess the effects of natural disturbances and human activities on soils and tree nutrition and growth of the Canadian boreal zone. Changes in soil and foliar nutrients following disturbance were also analyzed by meta-analysis. When sufficient replicated studies were not available for a given disturbance or nutrient, response assessments or narrative summaries are presented. The majority of fertilization studies in the boreal zone showed a positive tree growth response to nitrogen (N) and phosphorus (P) fertilization either individually or in combination. Large amounts of N may be lost through volatilization following fire depending on the severity and frequency of the fire. This may contribute to N limitation in the boreal zone. Available soil P and extractable calcium (Ca) and magnesium (Mg) increased in the surface horizons following fire. In contrast, extractable P decreased following harvest. Harvesting had no effect on total or inorganic N except in mixedwoods where total N decreased in the surface organic horizon following harvest. These are potential areas of concern given tree growth responses to N and P fertilization. Potassium (K) in the forest floor did not change following fire or harvesting; thus, K availability for tree nutrition should not be at risk, since its cycle is rapidly restored. Mercury (Hg) cycling may be altered in the boreal zone as a result of flooding and if fire return intervals and intensities increase. Interactions of multiple disturbances may increase the risk of nutrient depletions, but there is currently little information on these interactions in the boreal zone. Evidence to date suggests the soils of the Canadian boreal zone have not been adversely affected except in localized areas. However, there is the risk of nutrient loss if soils are not considered in our forest management strategies, particularly where multiple disturbances may interact. The potential for off-site movement of nutrients and contaminants into the atmospheric and aquatic ecosystems, in addition to on-site environmental issues, is also a concern. [ABSTRACT FROM AUTHOR]

Conservation efforts to sustain water resources and aquatic biodiversity in boreal watersheds will require reliable information on the recent status of various indicator species and an improved understanding of the risks to aquatic biodiversity posed by resource development activities. We reviewed the recent state of knowledge on the responses of aquatic biodiversity to forest management, pulp and paper mill effluents, hydroelectric impoundments, mining of minerals and metals, oil sands extractions, and peat mining and offer a prognosis for aquatic biodiversity under each of these environmental stressors. Despite the prevalence of natural resource development in Canada's largest forest ecosystem, there was a limited amount of published literature on the effects of many of the disturbance types on various indicators of aquatic biodiversity, making it difficult to produce a current and reliable status assessment. Across most of the boreal zone, there is a lack of coordinated, consistent data collection for many of the bioindicators and disturbance types discussed in this review. Forecasting the future state of aquatic biodiversity across the boreal zone is challenged by increasing natural resource development and its interactions with other stressors, especially climate change. The cumulative effects of multiple stressors coupled with resource development activities in boreal watersheds remain largely unknown. More importantly, the ecological thresholds for these cumulative effects (that is, the point at which aquatic ecosystems and their biodiversity cannot recover to a desired state within a reasonable time frame) are also unknown and remain gaps in our knowledge. The recent literature identifies a number of risks to aquatic biodiversity at local (tens of square kilometres) to regional (hundreds of square kilometres) scales associated with natural resource development. There are indications that many of these risks can be minimized by 'greener' technologies for resource development and reclamation, practical conservation planning and regulation, and increased stewardship in watershed management, although the effectiveness of many of these measures cannot yet be assessed from the published literature. [ABSTRACT FROM AUTHOR]

Source water protection (SWP) is the most important step in the implementation of a multi-barrier approach that ensures cost-effective delivery of safe drinking water. However, implementing SWP strategies can be a challenging task owing to technical and administrative issues. Decision support tools for effective implementation of SWP strategies can be very helpful that may lead to saving time and resources. This paper critically reviews different SWP strategies available for surface waters and also discusses various formulations for water quality assessment at the source. Source water quality regulations in Canada and other jurisdictions around the world are also discussed. Stormwater management ponds, vegetated filter strips, pollution control by effective agricultural practice (e.g., cover crop and crop rotation) and fencing are found to be frequently mentioned in those regulations. These strategies are discussed in details in terms of their key features to achieve the highest possible removal efficiencies for selected water quality parameters. Finally, a conceptual model is proposed to evaluate water quality changes at the source based on selected source water protection strategies. The model uses SWP strategies as a means to reduce possible pollutants in the source water. It also utilizes simple mass balance equations (dilution) to estimate the concentrations in the receiving water bodies and does not consider physico-chemical and other reactions. A surrogate measure, water quality index (WQI), based on selected water quality parameters, is used for the assessment of source water quality. [ABSTRACT FROM AUTHOR]

This paper synthesizes data extracted from the literature and data collected in various studies by the author on the quantity, characteristics, and functional importance of coarse woody debris (CWD) in the old-growth forests of British Columbia (B.C.). There is little agreement in the literature about the minimum diameter of CWD or the number of decay classes recognized. In western North America, five decay classes are commonly used, but recent studies suggest fewer decay classes are preferable. Comparisons among decay classes and biogeoclimatic zones and subzones in B.C. reveal that quantities and volumes are greatest (up to approximately 60 kg/m[sup 2] and approximately 1800 m[sup 3] /ha, respectively), and CWD persists the longest (sometimes in excess of 1000 years) in the Coastal Western Hemlock (CWH) biogeoclimatic zone. The quantity and ground cover of CWD increase with forest productivity. Persistence of CWD has varied from less than 100 to over 800 years in two coastal (CWH and Mountain Hemlock (MH)) and three interior (Interior Douglas-fir (IDF), Interior Cedar–Hemlock (ICH), and Engelmann Spruce – Subalpine Fir (ESSF)) biogeoclimatic zones. Trends in CWD quantity with forest age in managed coastal B.C. forests suggest a U-shaped curve, with greater quantities occurring in recent cutovers than in old-growth forests, and lowest quantities occurring in middle-aged forests. This may be the normal trend in CWD with forest age, with departures from this trend resulting from disturbance- or environment-specific factors. Relatively large amounts of data exist on the characteristics of CWD in the CWH, IDF, ICH, ESSF, and Boreal White and Black Spruce (BWBS) biogeoclimatic zones, but such data for the Coastal Douglas-fir, Sub-Boreal Pine–Spruce, Sub-Boreal Spruce (SBS), and Spruce–Willow–Birch biogeoclimatic zones appear relatively sparse. There have been few studies of the functional role of CWD in B.C. forests, but those studies that have been completed indicate that CWD is an important habitat component for some plant and animal species. A total of 169 plant species, including >95% of all lichens and liverworts, were found to grow on CWD in old-growth forests in the CWH, MH, IDF, ICH, and ESSF biogeoclimatic zones. One third of these species were restricted to CWD. Studies in several biogeoclimatic zones have found that CWD provided preferred habitat for and was associated with higher populations of some small animal species, such as shrews, some voles, and some salamanders, in old-growth forests, but the effects varied with species and biogeoclimatic zone. The nutrient cycling role of CWD is not yet well known, but it currently appears to be relatively insignificant in B.C. old-growth forests. Although it has been considered that CWD could increase mineral soil acidification and eluviation, no evidence for this was found in a study of the CWH, MH, IDF, ICH, ESSF, BWBS, and SBS biogeoclimatic zones. Future studies of the functional role of CWD should consider both scale (square metre vs. hectare) and temporal (changes in CWD with forest age) issues, as studies including these are sparse and both may be important. Key words: biogeoclimatic zones, British Columbia, coarse woody debris, old-growth forests.Cette communication résume les données tirées de la littérature et celles recueillies par l'auteur dans diverses études sur la quantité, les caractéristiques et l'importance fonctionnelle des débris ligneux grossiers (DLG) dans les forêts anciennes de la Colombie-Britannique (C.-B.). Dans la littérature, on ne s'entend pas sur le diamètre minimum des DLG, ou le nombre de classes de décomposition. Dans l'ouest de l'Amérique du Nord, on emploie le plus souvent cinq classes, mais des études récentes portent à croire qu'un nombre de classes inférieur serait préférable. Les comparaisons entre les classes de décomposition et les zones et sous-zones biogéoclimatiques de la C.-B. révèlent que les DLG sont plus abondants (pouvant atteindre environ 60 kg/m[sup 2] et 1800 m[sup 3] /ha) et persistent le plus longtemps (parfois pendant plus de 1000 ans) dans la zone biogéoclimatique cótière de la pruche de l'Ouest (CWH). L'abondance des DLG et la superficie de sol qu'ils couvrent augmentent avec la productivité de la forêt. La persistance des DLG varie de moins de 100 ans à plus de 800 ans dans cinq zones biogéoclimatiques : deux zones côtières (la CWH et la zone de la pruche subalpine (MH)) et trois zones intérieures (celle du douglas taxifolié de l'intérieur (IDF), celle des cèdres et des pruches de l'intérieur (ICH) et celle de l'épinette d'Engelmann et du sapin subalpin (ESSF)). Dans les forêts côtières aménagées de la C.-B., l'abondance des DLG en fonction de l'âge de la forêt suivrait une courbe en U, les débris étant plus abondants sur les parterres de coupe récents que dans les forêts anciennes, et moins abondants dans les forêts d'âge moyen. Cette relation entre les DLG et l'âge de la forêt est peut-être la tendance normale, et les écarts par rapport à celle-ci pourraient être le résultat de facteurs propres à chaque perturbation ou milieu. Il existe beaucoup de données sur les caractéristiques des DLG dans la CWH, la IDF, la ICH, la ESSF et la zone boréale des épinettes blanche et noire (BWBS), mais il en existe relativement peu pour la zone côtière du douglas taxifolié, la zone subboréale des pins et des épinettes, la zone subboréale de l'épinette (SBS) et la zone de l'épinette, du saule et du bouleau. Peu d'études ont été consacrées au rôle fonctionnel des DLG dans les forêts de la Colombie-Britannique, mais d'après celles qui ont été réalisées, les DLG constitueraient une composante importante de l'habitat de certaines espèces végétales et animales. On a recensé 169 espèces végétales poussant sur ces débris, dont plus de 95 % de tous les lichens et hépatiques, dans les forêts anciennes de la CWH, de la MH, de la IDF, de la ICH et de la ESSF. Le tiers de ces espèces ne poussent que sur les DLG. D'après des études effectuées dans plusieurs zones biogéoclimatiques, ces débris constituent l'habitat préféré de certains petits animaux présents dans les forêts anciennes, tels que les musaraignes, certains campagnols et certaines salamandres, et sont associés à de plus fortes populations de ces animaux, mais les effets varient selon l'espèce et la zone biogéoclimatique. Le rôle des DLG dans le recyclage des éléments nutritifs n'est pas bien connu, mais il semble qu'il soit relativement négligeable dans les forêts anciennes de la C.-B. Il a été avancé que les débris ligneux grossiers pourraient accroître l'acidification et le lessivage des sols minéraux, mais de tels effets n'ont pas été mis en évidence dans une étude de la zone CWH, de la MH, de la IDF, de la ICH, de la ESSF, de la BWBS et de la SBS. À l'avenir, les études sur le rôle fonctionnel des DLG devraient tenir compte des aspects liés à l'échelle (m[sup 2] ou ha) et temporels (modifications des DLG avec le vieillissement de la forêt) puisque les études impliquent ces paramètres potentiellement importants sont rares. Mots clés : zones biogéoclimatiques, Colombie-Britannique, débris ligneux grossiers, forêts anciennes. [Traduit par la rédaction] [ABSTRACT FROM AUTHOR]