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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]

Most forest managers view natural regeneration of Picea glauca (white spruce) after forest harvesting to be unreliable; in this paper the Authors dispute this idea by describing the factors influencing natural regeneration of spruce, i.e., seed production, dispersal, germination and seedling establishment and discussing the opportunities for encouragement of natural regeneration after logging. Seed supply is greatest from trees with large crowns, that are positioned in the upper canopy and seeding is greatest in mast years. Maintaining at least five mature white spruce trees per hectare within cut areas or dense stands of spruce on edges of cutovers ensures pollination success as well as even seed distribution. The most suitable seedbeds for white spruce germination are mineral soil, mineral soil with a thin organic layer, or large downed rotten logs. Mineral soil seedbeds are available for a short time after fire or other disturbances, while downed wood becomes available over time; this results in recruitment immediately after disturbance or several decades later. To increase the availability of suitable seedbeds the soil can be scarified during or after harvest and nurse logs should be left; on wet sites mounding should be considered. Partial canopy cover can protect seedlings from climate extremes while limiting competing vegetation. Using natural regeneration, a range of stocking outcomes can be expected--from no stocking to overstocking of spruce. Such variation in the amount of spruce versus broadleaf species, however, is consistent with the range of variation in forest composition found naturally in the boreal mixedwood region. [ABSTRACT FROM AUTHOR]