Pattern and process in forest bird communities on boreal landscapes originating from wildfire and timber harvest

2009 ◽  
Vol 85 (2) ◽  
pp. 218-226 ◽  
Author(s):  
Sarah A Wyshynski ◽  
Thomas D Nudds
Keyword(s):  
Species Richness ◽  
Boreal Forest ◽  
Boreal Forests ◽  
Natural Disturbance ◽  
Timber Harvest ◽  
Forest Stand ◽  
Null Models ◽  
Bird Communities ◽  
Forest Practices ◽  
Boreal Landscapes

Policy direction to emulate natural disturbance in managed boreal forests has spurred a need to contrast the dynamics of biota on landscapes originating from timber harvest and from wildfire (hereafter, “managed” and “natural”). Typically, emphasis is on pattern emulation, and less on processes, such as competition, predation or habitat selection. Knowing how communities in the boreal forest assemble can provide further insight to the effects of anthropogenic disturbance on the processes responsible, permitting assessments about whether forestry practices emulate processes as well as patterns. We contrasted variation in species richness among forest types, with stand area, and between local (forest stand) and regional (landscape) scales on managed and natural boreal landscapes in NW Ontario. Species richness varied more among forest stand types than between landscapes, or with stand area, on either landscape. On both landscapes, mean local species richness was 1/3 of regional richness, consistent with the hypothesis that competition structured stand-level assemblages regardless of stand origin. We further compared the structure of stand-level assemblages from randomized null models using presence/absence and abundance data with observed assemblages on each landscape, while controlling for variation in habitat structure among stands. Local bird assemblages were over-dispersed in niche space relative to random assemblages, also consistent with the competition hypothesis, regardless of stand origin. We found no evidence that patterns of variation in diversity of songbirds and woodpeckers, nor the processes that govern them, differed between managed and natural boreal forest landscapes. Our results suggest that past forest practices in this region, if by default, nevertheless emulated natural patterns of variation in diversity and species assembly of bird communities. Key words: boreal forest, songbirds, woodpeckers, community assembly, null models, natural disturbance emulation, forestry, Ontario

scholarly journals Partial harvesting in the Canadian boreal: Success will depend on stand dynamic responses

2007 ◽  
Vol 83 (3) ◽  
pp. 319-325 ◽  
Author(s):  
H C Thorpe ◽  
S C Thomas
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Biological Diversity ◽  
Empirical Studies ◽  
Natural Disturbance ◽  
Dynamic Responses ◽  
Post Harvest ◽  
Partial Harvest ◽  
Partial Harvesting ◽  
Structural Retention

In the past 10 to 15 years, alternative silvicultural treatments involving partial harvesting have been developed for boreal forests, with the goal of achieving a balance between biodiversity maintenance and continued timber production. Most prior research has focussed on the impacts of partial harvesting on biological diversity, while stand dynamic responses remain little studied. In this paper we explore partial stand harvesting in the Canadian boreal—its rationale, current extent, and impact on stand dynamic patterns. Empirical studies from the boreal and elsewhere indicate that residual trees of many species respond to partial harvesting with enhanced growth, commonly showing a lagged response after which peak growth occurs five to 25 years following harvest. Post-harvest mortality is also prevalent but much more variable, with losses of residual trees ranging from nearly zero to more than 50% above background mortality rates in the initial years following harvest. With the exception of strip cutting in parts of northern Ontario and Quebec (HARP/CPPTM), operational partial harvesting in the Canadian boreal currently involves very low levels of retention. Available data suggest that such low retention levels, particularly when spatially dispersed, generally result in unacceptably high rates of post-harvest mortality, which are unlikely to be offset by increases in residual tree growth. There is an urgent need for development of spatially explicit stand simulation models that will allow accurate yield predictions for partial harvest systems to assess their feasibility in boreal forest management. Key words: ecosystem management, natural disturbance emulation, boreal forest, partial cut, structural retention, growth response, windthrow, post-harvest mortality

Bird communities associated with live residual tree patches within cut blocks and burned habitat in mixedwood boreal forests

2000 ◽  
Vol 30 (8) ◽  
pp. 1281-1295 ◽  
Author(s):  
Jim Schieck ◽  
Keith A Hobson
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Bird Communities ◽  
Forest Birds ◽  
Forest Bird ◽  
Post Harvest ◽  
Riparian Habitats ◽  
Residual Tree ◽  
Mixedwood Boreal Forest ◽  
Trees And Shrubs

By retaining patches of trees in cut blocks, managers expect to retain some forest birds and create bird communities more similar to those found after fires. We surveyed birds from a range of patch sizes (1 to >3000 live residual trees), at four ages (2, 15, 30, 60 years), following two disturbance types (harvest, fire) in mixedwood boreal forest. Bird communities varied among patch sizes, forest ages, and disturbance types. Immediately post-disturbance, bird communities from large patches (>100 residual trees) were more similar to those from old forest than were communities from small patches ([Formula: see text]10 residual trees). Birds that nest or forage in open or riparian habitats had highest densities in small patches 2 years post-harvest, whereas birds that nest in large snags had highest densities in small patches 2 years post-fire. Throughout the chronosequence following both disturbance types, birds from small patches became more similar to those from old forest. Birds that nest and forage in small trees and shrubs were common 15 and 30 years post-disturbance, and generalist forest birds were common 60 years post-disturbance. Birds associated with old forest were present in all patch sizes 15, 30, and 60 years post-disturbance, although larger patches had higher densities of these species.

scholarly journals Environment and biogeography of the western boreal forest

1996 ◽  
Vol 72 (1) ◽  
pp. 51-58 ◽  
Author(s):  
Jim Pojar
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Canadian Shield ◽  
Distinctive Character ◽  
Aspen Parkland ◽  
Western Boreal Forest ◽  
Boreal Landscapes ◽  
Boreal Climate ◽  
Eastern Species ◽  
Broad Scale

The western boreal forest of North America (Manitoba through Alaska) has a typical boreal climate, but the largely sedimentary Interior Plains and the northern Cordillera (part of which was ice-free in the Pleistocene) are physiographically and geologically very different from the Canadian Shield that underlies most of the eastern boreal forest. The mountainous nature of much of the region, with pronounced topography, local climates, aspect differences, sharp drainage, and elevational clines, gives some of its boreal landscapes a different character from those of the Shield. The region's forests are structurally consistent with boreal forests everywhere, but floristic differences are apparent, with the loss of eastern species and the addition of Cordilleran and Beringian elements. The southern margins of the western boreal forest also have a distinctive character, as they merge with either the Cordilleran subalpine forests or with aspen parkland and grassland—not with Great Lakes-St. Lawrence conifer-hardwood forests.Several different biogeographic or ecological land classifications have been applied to the western boreal forest. Although there are a variety of classifications, several common themes are apparent. Broad-scale zonation reflects 1) latitudinal change (boreal forest to subarctic woodland to forest-tundra ecotone, from south to north), 2) physiography and biogeography (Plains/Shield to northern Cordillera to Alaska-Beringia, from east to west), and 3) the physiographic vs. vegetation bias of the classification. Regardless of higher-level, broad-scale differences, the various classifications tend to be consistent at the site level, and therefore all have some value and utility for foresters.

Boreal Biome

Ecology ◽  
2013 ◽  
Author(s):  
Lee E. Frelich
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Large Scale ◽  
Trophic Structure ◽  
Natural Disturbance ◽  
Conservation Strategies ◽  
Boreal Ecosystems ◽  
High Severity ◽  
Ecological Theories ◽  
Effective Conservation

The boreal biome, with vast forests across northern North America, Europe, and Asia, has been of interest since the science of ecology got its start in the late 1800s. Many also refer to the boreal forest as “taiga,” and the two terms are considered interchangeable here. Scientists, conservationists, and forest managers have long realized that the difficulty of traveling in the remote territory of the boreal forest offers the chance to characterize the natural ecological function and design effective conservation strategies prior to large-scale exploitation by humans. There are key insights to be gained into ecological theories related to community structure, trophic structure, disturbance ecology, and landscape ecology. Large-scale intact boreal ecosystems allow studies of trophic interactions including top-level predators, landscape dynamics created by natural disturbance, and comparison of natural and human disturbance. Boreal forests reign supreme as places to study large-scale high-severity fires. Essentially, boreal forests have the room to make it possible to carry out studies that cannot be done in the temperate zones, where so much of the landscape has been converted to human usages. These forests also have a large impact on global ecology through interactions with the climate system, carbon storage, and timber resources. The global importance of the boreal forest in the context of global warming has propelled a rapidly growing investment in research during the last few decades.

scholarly journals Dynamics of Territorial Occupation by North American Beavers in Canadian Boreal Forests: A Novel Dendroecological Approach

Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 221 ◽  
Author(s):  
Julie-Pascale Labrecque-Foy ◽  
Hubert Morin ◽  
Miguel Montoro Girona
Keyword(s):  
Boreal Forest ◽  
North American ◽  
Water Body ◽  
Boreal Forests ◽  
Castor Canadensis ◽  
Natural Disturbance ◽  
Water Levels ◽  
The North ◽  
Patterns Of Use ◽  
Over Time

Research Highlights: Our study highlights a new, simple, and effective method for studying the habitat use by beavers in Canadian boreal forests. Information regarding the presence of beaver colonies and their habitat occupation is essential for proper forest management and damage prevention in the boreal forest. Background and Objectives: The North American beaver (Castor canadensis) is a major element of natural disturbance, altering the dynamics and structure of boreal forest landscapes. Beaver-related activities also affect human infrastructure, cause floods, and lead to important monetary losses for forestry industries. Our study aimed to determine the spatiotemporal patterns of beaver occupation of lodges over time. Materials and Methods: Using a dendroecological approach to date browsing activity, we studied the occupation of two lodges per water body for eight water bodies located in the boreal forest of Québec, Canada. Results: Three sites showed alternating patterns of lodge use (occupation) over time, three sites (37.5%) demonstrated no alternating patterns of use, and two sites (25%) presented unclear patterns of lodge use. Conclusions: Alternating patterns of lodge use can be linked to food depletion and the need to regenerate vegetation around lodges, while non-alternating patterns may be related to fluctuations in water levels, the specific shrub and tree species surrounding the lodges, the size of the beaver territory, and the number of lodges present on a water body.

scholarly journals Snag abundance 20, 30, and 40 years following fire and harvesting in boreal forests

2003 ◽  
Vol 79 (3) ◽  
pp. 541-549 ◽  
Author(s):  
Steven H Ferguson ◽  
Philip C Elkie
Keyword(s):  
Forest Management ◽  
Boreal Forests ◽  
Woody Debris ◽  
Ecological Factors ◽  
Basal Area ◽  
Natural Disturbance ◽  
Timber Harvest ◽  
Stem Density ◽  
Dead Trees ◽  
Diameter Classes

The retention of standing dead trees (snags) has become an important conservation concern, especially when forest management efforts attempt to emulate natural disturbance. We investigate the abundance of snags within Ontario's boreal forest following 10–20, 21–30, and 31–40 years of both fire and forest harvest disturbance over a 24 000-km2 area. Fire frequency varied considerably, with 90% of the fires in the study area occurring in the 1970s. We did not detect differences in basal area of snags (m2/km2) between burned and harvested stands. However, differences occurred in dead-stem density (number/km2); the burned stands produced more snags in the 21- to 30-year post-disturbance class and the harvested stands produced more snags in the 31- to 40-year post-disturbance class. Similarly, the distribution of diameter classes of snags differed between the burned and harvested stands. In size classes greater than 32 cm (diameter at breast height), we found more snags in the harvested forests 21–40 years following disturbance. We did not find differences in the basal area of snags between disturbance types, whether they were hardwood or softwood. However, hardwood snags occurred in greater abundance in the larger diameter classes. Our findings are limited by the changing timber harvest treatments (selective harvest, clearcut, and ecological cut), the small number of disturbance events, and the variety of stand compositions. More research is required on the ecological factors influencing snag abundance to improve development of local forest management plans and to design landscapes that conserve forest structure and biodiversity. Key words: biodiversity, clearcut, conservation, coarse woody debris, dead trees, forest management, landscape, snags, wildlife

Natural disturbance emulation in boreal forest ecosystem management — theories, strategies, and a comparison with conventional even-aged management1This article is one of a selection of papers from the 7th International Conference on Disturbance Dynamics in Boreal Forests.

2012 ◽  
Vol 42 (7) ◽  
pp. 1185-1203 ◽  
Author(s):  
Timo Kuuluvainen ◽  
Russell Grenfell
Keyword(s):  
Forest Management ◽  
Boreal Forest ◽  
Boreal Forests ◽  
Sustainable Forest Management ◽  
Natural Disturbance ◽  
Management Approach ◽  
Disturbance Factor ◽  
Management Schemes ◽  
Unmanaged Forest ◽  
Ecologically Sustainable

Natural disturbance emulation (NDE) has been proposed as a general approach to ecologically sustainable forest management. We reviewed the concepts, theories, and strategies related to NDE in boreal forest management. We also reviewed publications that discussed NDE in the boreal forest in general and those that specifically compared NDE-based management with conventional even-aged management. The papers generally focused on northern North America and landscape-scale wildfire as the main disturbance factor, whereas information from Eurasia was exclusively theoretical. Within this limited scope, NDE was generally found to have a positive effect on biodiversity in terms of forest structure and species diversity when compared with conventional even-aged management. Studies on timber supply and social implications of NDE were so few that they preclude generalizations. We conclude that the ecological and economic performance of NDE as a management approach still remains poorly examined. To advance the development of NDE, particular attention should be given to (1) augmenting the knowledge base on natural range of variability of unmanaged forest ecosystems and evaluating the validity of this information in a changing climate, (2) fostering multidisciplinary research with better integration of ecological theory to both integrative and analytical research on NDE, and (3) better integration of socioeconomic concerns, adaptive management schemes, and international collaboration into NDE initiatives.

An introduction to Canada’s boreal zone: ecosystem processes, health, sustainability, and environmental issues

2013 ◽  
Vol 21 (4) ◽  
pp. 207-226 ◽  
Author(s):  
J.P. Brandt ◽  
M.D. Flannigan ◽  
D.G. Maynard ◽  
I.D. Thompson ◽  
W.J.A. Volney
Keyword(s):  
Climate Change ◽  
Boreal Forests ◽  
Native Species ◽  
Natural Disturbance ◽  
Timber Harvest ◽  
Ecosystem Dynamics ◽  
Present Condition ◽  
Boreal Zone ◽  
Climate Change Effects ◽  
The Past

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.

Functional evenness of bird communities varies along the elevational gradient in Europe: Conservation implications

2019 ◽  
Author(s):  
Federico Morelli ◽  
Yanina
Keyword(s):  
Species Richness ◽  
Elevation Gradient ◽  
Bird Species ◽  
Elevational Gradient ◽  
Negative Association ◽  
Bird Communities ◽  
Breeding Bird ◽  
Bird Species Richness ◽  
Large Spatial Scale ◽  
Functional Evenness

ContextThe negative association between elevation and species richness is a well-recognized pattern in macro-ecology. ObjectivesThe aim of this study was to investigate changes in functional evenness of breeding bird communities along an elevation gradient in Europe. MethodsUsing the bird data from the EBCC Atlas of European Breeding Birds we estimated an index of functional evenness which can be assumed as a measure of the potential resilience of communities.ResultsOur findings confirm the existence of a negative association between elevation and bird species richness in all European eco regions. However, we also explored a novel aspect of this relationship, important for conservation: Our findings provide evidence at large spatial scale of a negative association between the functional evenness (potential community resilience) and elevation, independent of the eco region. We also found that the Natura2000 protected areas covers the territory most in need of protection, those characterized by bird communities with low potential resilience, in hilly and mountainous areas.ConclusionsThese results draw attention to European areas occupied by bird communities characterized by a potential lower capacity to respond to strong ecological changes, and, therefore, potentially more exposed to risks for conservation.

Lack of congruence between terrestrial and epiphytic lichen strata in boreal forests

2021 ◽  
Vol 53 (1) ◽  
pp. 149-158
Author(s):  
Robert J. Smith ◽  
Sarah Jovan ◽  
Susan Will-Wolf
Keyword(s):  
Species Richness ◽  
Boreal Forests ◽  
Environmental Gradients ◽  
Ground Layer ◽  
Global Changes ◽  
Layer Versus ◽  
Epiphytic Lichen ◽  
Incremental Change ◽  
Compositional Gradients ◽  
Environmental Responses

AbstractLichens occupy diverse substrates across tremendous ranges of environmental variation. In boreal forests, lichen communities co-occur in ‘strata’ defined by terrestrial or arboreal substrates, but these strata may or may not be interchangeable as bioindicators. Do co-occurring lichen strata have similar community structures and environmental responses? Could one stratum serve as a proxy for the other? We assessed variation in species richness and community compositions between ground-layer versus epiphyte-layer lichen strata in boreal forests and peatlands of interior Alaska. Species richness was lower and more spatially structured in the ground layer than the epiphyte layer. Richness of strata was not correlated. The most compositionally unique ground-layer communities were species-poor but contained regionally rare species not common in other plots. Variation in community compositions (ordination scores) were not congruent between strata (Procrustes congruence < 0.16 on 0–1 scale); the largest departures from congruence occurred where ground layers were species-poor. The best predictors of ground-layer community compositions were hydrological and topographic, whereas epiphytes were most associated with macroclimate and tree abundances. We conclude that lichens on different substrates ‘move in different circles’: compositional gradients did not agree and the environmental gradients most important to each lichen stratum were not the same. The conditions which strongly influence one vegetation stratum may have little bearing upon another. As global changes modify habitats, an incremental change in environment may lead community trajectories to diverge among lichen strata.

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