Ian D. Thompson

An operational framework for defining and monitoring forest degradation.

Forest degradation is broadly defined as a reduction in the capacity of a forest to produce ecosystem services such as carbon storage and wood products as a result of anthropogenic and environmental changes. The main causes of degradation include unsustainable logging, agriculture, invasive species, fire, fuelwood gathering, and livestock grazing. Forest degradation is widespread and has become an important consideration in global policy processes that deal with biodiversity, climate change, and forest management. There is, however, no generally recognized way to identify a degraded forest because perceptions of forest degradation vary depending on the cause, the particular goods or services of interest, and the temporal and spatial scales considered. Here, we suggest that there are types of forest degradation that produce a continuum of decline in provision of ecosystem services, from those in primary forests through various forms of managed forests to deforestation. Forest degradation must be measured against a desired baseline condition, and the types of degradation can be represented using five criteria that relate to the drivers of degradation, loss of ecosystem services and sustainable management, including: productivity, biodiversity, unusual disturbances, protective functions, and carbon storage. These criteria are not meant to be equivalent and some might be considered more important than others, depending on the local forest management objectives. We propose a minimum subset of seven indicators for the five criteria that should be assessed to determine forest degradation under a sustainable ecosystem management regime. The indicators can be remotely sensed (although improving calibration requires ground work) and aggregated from stand to management unit or landscape levels and ultimately to sub-national and national scales.

A review of the long-term effects of post-harvest silviculture on vertebrate wildlife, and predictive models, with an emphasis on boreal forests in Ontario, Canada

Greater fibre yields may be possible in commercial forests through an increased application of post-harvest silvicultural techniques. In Canadian boreal forests, while basic silvicultural regeneration techniques such as planting, seeding, scarifying, and tending, have been employed since the 1940’s, more intensive techniques (intensive forest management (IFM)) such as increased area planted, pre-commercial and commercial thinning, extra tending events, fertilizing, and short rotations may soon be used. There may be effects of basic and more intensive silviculture on biodiversity in the long-term, compared to natural regeneration following logging or especially stand development following natural disturbances. We reviewed approximately 50 papers that reported studies of the long-term effects of post-harvest silviculture on vertebrate wildlife. In particular, large impacts to biodiversity universally occur when native forest types are replaced by rapidly-growing exotic tree species. However, in boreal forests, native tree species are usually planted, and so any effects on associated wildlife communities may be considerably less than in non-native species plantations. Limited long-term information is available, but published studies of effects of basic silviculture and IFM suggested that loss of structures in forest stands was an important common impact that resulted in vertebrate species responses. Fewer structural features in managed forests compared to in natural forests likely results in reduced numbers of animal species dependent on those structures, such as cavity-using species and species for which large decaying woody debris is important. Simplifying stand structures and species composition may result in systems with low connectivity, making them vulnerable to insect and mammalian herbivory. Concentration of IFM in stands on highly productive sites could exacerbate effects (positive or negative), owing to the positive relationship between forest productivity and animal and plant diversity. Species such as black-backed woodpeckers (Picoides arcticus) may be reduced over large areas by stand conversion to mixedwoods, stand structural changes and especially age-class truncation. On the other hand, IFM may contribute increased habitats to species favoring young to mature coniferous-dominated forests, that normally decline across a landscape following clearcutting in boreal mixed and upland conifer stands. An aspatial model, based on published and local information and expert opinion, suggested that IFM and post-harvest silviculture in Ontario’s boreal forests would produce positive and negative species-specific effects on the vertebrates that we modeled. However, IFM appeared to result in little increased effect over basic post-harvest silviculture. We also expect that stand-level effects of IFM on species would accumulate through time over landscapes, as more stands come under intensive management and the level of effects will be cumulative.

Habitat selection by forest bats in relation to mixed-wood stand types and structure in Central Ontario

Recent studies have suggested that old-growth forests may be important habitat for some species of bats, but the proximate factors related to greater bat activity in older forests are not well understood. To assess relative habitat use by bats, we used ultrasonic detectors and mist nets to sample bat activities among old-growth white pine (Pinus strobus) mixed woods, mature white pine mixed woods, boreal-type mixed woods, and selectively logged white pine mixed woods in central Ontario. We Quantified 15 structural characteristics in the 21 stands sampled for bat activity. Detection rates of Myotis species, silver-haired bats (Lasionycteris nocitvagans), and hoary bats (Lasiurus cinereus) were 2.7-14.0 times greater in old-growth white pine mixed-wood stands than in other stand types (Ps < 0.05). Multivariate habitat models suggested that, between logged and uncut stands, the availability of potential roost sites may be an important determinant of bat activity for Myotis species and silver-haired bats. Among uncut stands, our habitat models suggested that snag availability was not an important variable affecting habitat selection by bats. Rather, bat detection rates in uncut forests were correlated with canopy and subcanopy structure. Little brown bats (Myotis lucifugus) and northern long-eared bats (M. septentrionalis) may spatially separate for feeding To maintain habitat for bats, forest managers should implement timber harvest strategies that retain remnant old-growth white pine stands in the landscape, preserve snags and large live trees in selectively logged forests, and promote regeneration of second-growth white pine stands to old age rather than truncating age classes at younger ages.

Marten Populations in Uncut and Logged Boreal Forests in Ontario

I hypothesized that logged boreal forests were suboptimal habitat for marten (Martes americana) and that marten using such areas may have higher mortality and poorer productivity than in uncut forests. I compared marten demography in uncut forest with that in logged forests 3-40 years old. Uncut forests were dominated by coniferous trees, with several vertical layers of vegetation, moss ground cover, and a dense overhead canopy in winter. All ages of logged forests were dominated by deciduous tree and shrub species, few vertical layers of vegetation, litter ground cover, and an open canopy in winter. Marten density indices were about 90 % greater in uncut forests (0.8-1.1 marten/km 2 ) than in logged forests (0.08-0.2 marten/km 2 ). Marten resident in uncut forest rarely used adjacent logged forests

Range Extent and Stand Selection for Roosting and Foraging in Forest-Dwelling Northern Long-Eared Bats and Little Brown Bats in the Greater Fundy Ecosystem, New Brunswick

Abstract To understand bat biology and appreciate their dependence on and role within forested ecosystems, the biological resolution at which studies are directed must elucidate species and gender patterns. We studied species- and gender-specific aspects of summer range extent and stand selection in northern long-eared bats (Myotis septentrionalis) and little brown bats (M. lucifugus) in the Greater Fundy Ecosystem, New Brunswick, Canada, using trapping, radiotelemetry, and ultrasonic monitoring. Our results suggested that this 2-species system is comprised of 4 ecologically distinct groups with respect to site selection and range extent for roosting and foraging. All bats exhibited an affinity to specific roosting areas. Myotis septentrionalis roosted and foraged in the forest interior. The roosting and foraging areas for females were 6.1 times and 3.4 times larger, respectively, than for males. Both genders foraged in site types in proportion to their availability. Myotis lucifugus females roosted in buildings outside the core study area, and those captured in the forested landscape were transients. Compared to male and female M. septentrionalis, male M. lucifugus had intermediate-sized roosting areas but the largest foraging areas. Water sites were selected during foraging more than expected. Bat foraging activity, measured acoustically at 8 site types, was greatest at lakes and least above the forest canopy. Male M. lucifugus activity levels were positively associated with temperature and the amount of mature coniferous forest and water within 1 km of the sampling site, and they were negatively associated with the amount of mature deciduous forest within 1 km of the site. Our results suggested that understanding gender effects is crucial for accurate characterization of forest bat habitats. Studies of bats that combine data for genders, species, or guilds may produce spurious results and may be of minimal value for, or actually hinder, bat conservation and management programs.

Forest Biodiversity and the Delivery of Ecosystem Goods and Services: Translating Science into Policy

Biodiversity is integral to almost all ecosystem processes, with some species playing key functional roles that are essential for maintaining the value of ecosystems to humans. However, many ecosystem services remain nonvalued, and decisionmakers rarely consider biodiversity in policy development, in part because the relationships between biodiversity and the provision of ecosystem services are not generally appreciated. To date, the majority of work in which the functional importance of biodiversity has been examined has been conducted in relatively species-poor systems. Focusing on forest and agroforest systems, we synthesize recent research on the role of biodiversity in the provision of ecosystem services and provide examples of biodiversity science that informs ecosystem management and policy. Finally, we highlight barriers to the transfer of knowledge from scientists to decisionmakers and suggest that scientists can be much more effective at informing policy and improving resource management by asking policy-relevant questions and providing timely and consistent information to decisionmakers and the public on the linkages among biodiversity, ecosystem services, and their value to people.

Marten activity in uncut and logged boreal forests in Ontario

Marten (Martes americana) experience greater survival and production rates in old growth forests than in postclear-cut forests. To determine whether total time active and foraging success contribute to these differences, we compared marten movements and hunting activities in their preferred old-forest habitats to those in logged forests. Marten in uncut forests captured up to 119 % (P = 0.003) more prey biomass than those in logged forests, depending on prey populations. We found few marten activity differences by forest type attributable to differences in density and prey species,or habitat structure. Distances between core areas in individual home ranges were greater (P < 0.001) in logged forests than in uncut forests

Avian communities of mature balsam fir forests in Newfoundland: Age-dependence and implications for timber harvesting

The amount of old growth balsam fir (Abies balsamea) forest (SO+ years) in Newfoundland, Canada has declined and management towards a 60.year rotation age will further reduce the availability of old forest as wildlife habitat. We distinguished among three mature age-classes of forests (40-59, 60-79, and 80+ years) based on tree density, canopy gaps, woody debris, and moss and litter cover on the ground. Canonical correspondence analysis revealed two groups of stands: one containing all of the 40-year-old stands and most 60-year-old stands, and a second that included old growth stands and 4 of 10 60-ycarold stands. Forest birds were separated into four groups: one preferring the youngest stands, another observed primarily in old stands, and two others that were intermediate. Bird species richness was greater in 40.year-old forests than in 60+ and 80+-year-old stands. Blackbacked Woodpecker (Picoides arcticus) and Gray-cheeked Thrush (Hylocichla minima) were most abundant in old forests. Six other species also were grouped together with the latter two as an old forest group. We observed more species and more total birds breeding on productive forest site types than on less-productive sites based on a forest ecosystem classification, and five species showed significant relationships between density and site quality. We observed few relationships between stand age and migratory strategy. The only guild for which there was a significant relationship of abundance with forest age was cone seedcaters, which were more common in second-growth forests than in old forest. To maintain avian diversity in these forest landscapes, some stands must be allowed to develop as old growth.

Woodpecker abundance and habitat use in mature balsam fir forests in Newfoundland.

Availability of the oldest age-class of balsam fir (Abies balsamea) forest, the major forest type of western Newfoundland, is declining through logging, insect effects, and management for a 60-year harvest rotation. Loss of old-growth balsam fir forests may limit the availability of woodpecker habitat if nesting trees and feeding substrates are most abundant in these later successional stages. We assessed abundance of black-backed woodpeckers (Picoides arcticus), downy woodpeckers (P. pubescens), and hairy woodpeckers (P. villosus) in 10 stands in each of 3 forest age classes (40-59, 60-79, and >80 yr) of balsam fir in western Newfoundland. For each stand, we quantified 10 habitat variables that may have influenced habitat use by woodpeckers. Black-backed woodpeckers were almost exclusively found in >80-year-old forests. Density of black-backed wood-peckers was significantly related to number of large snags, but negatively to the total number of dead stems. Downy woodpeckers were common and similarly distributed among the 3 forest age classes, and hairy wood-peckers were uncommon and only observed in the 40- and 60-year age classes. Downy and hairy woodpeckers were significantly associated with the number of white birch snags in the stands, a resource that declined with forest age. A reduction in the amount of forest in the oldest age class is probably reducing the population of black-backed woodpeckers in western Newfoundland. We recommend a series of fixed-width transects, coupled with point counts using call broadcasts, as an effective means of surveying woodpeckers. Forest managers must maintain large areas of old forests, temporally and spatially, to maintain black-backed woodpeckers in Newfoundland.

Mortality risk increases with natal dispersal distance in American martens.

The assumption that mortality risk increases with dispersal distance has rarely been tested. We compared patterns of natal dispersal in the American marten (Martes americana) between a large regenerating forest landscape and an uncut landscape that was dominated by more mature forest to test whether mortality risk increased with dispersal distance, and whether variation in mortality risk influenced dispersal distance. Mortality risk increased with dispersal distance in both landscape treatments, but the distance-dependent increase in mortality in the regenerating landscape was twice that in the uncut landscape. Differences in body condition, supported by other data on foraging efficiency, suggested that juveniles from the regenerating landscape were less able to cope with the energetic demands of dispersal compared with juveniles from older forests. Juveniles travelled shorter distances in the regenerating versus uncut landscape. These results implied that dispersal was costly in terms of juvenile survival and that mean dispersal distance was shaped, in part, by mortality risk.