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1.
Brian Young John Yarie David Verbyla Falk Huettmann Keiko Herrick F. Stuart ChapinIII 《Landscape Ecology》2017,32(2):397-413
Context
Patterns of forest diversity are less well known in the boreal forest of interior Alaska than in most ecosystems of North America. Proactive forest planning requires spatially accurate information about forest diversity. Modeling is a cost-efficient way of predicting key forest diversity measures as a function of human and environmental factors.Objectives
Investigate and predict the patterns and processes in tree species and tree size-class diversity within the boreal forest of Alaska for a first mapped quantitative baseline.Methods
For the boreal forest of Alaska, USA, we employed Random Forest Analysis (machine learning) and the Boruta algorithm in R to predict tree species and tree size-class diversity for the entire region using a combination of forest inventory data and a suite of 30 predictors from public open-access data archives that included climatic, distance, and topographic variables. We developed prediction maps in a GIS for the current levels (Year 2012) of tree size-class and species diversity.Results
The method employed here yielded good accuracy for the huge Alaskan landscape despite the exclusion of spectral reflectance data. It’s the first quantified GIS prediction baseline. The results indicate that the geographic pattern of tree species diversity differs from the pattern of tree size-class diversity across this forest type.Conclusions
The results suggest that human factors combined with topographical factors had a large impact on predicting the patterns of diversity in the boreal forest of interior Alaska.2.
Watershed analysis of forest fragmentation by clearcuts and roads in a Wyoming forest 总被引:14,自引:0,他引:14
Tinker Daniel B. Resor Catherine A.C. Beauvais Gary P. Kipfmueller Kurt F. Fernandes Charles I. Baker William L. 《Landscape Ecology》1998,13(3):149-165
Remotely sensed data and a Geographic Information System were used to compare the effects of clearcutting and road-building on the landscape pattern of the Bighorn National Forest, in north-central Wyoming. Landscape patterns were quantified for each of 12 watersheds on a series of four maps that differed only in the degree of clearcutting and road density. We analyzed several landscape pattern metrics for the landscape as a whole and for the lodgepole pine and spruce/fir cover classes across these maps, and determined the relative effects of clearcutting and road building on the pattern of each watershed. At both the landscape- and cover class-scales, clearcutting and road building resulted in increased fragmentation as represented by a distinct suite of landscape structural changes. Patch core area and mean patch size decreased, and edge density and patch density increased as a result of clearcuts and roads. Clearcuts and roads simplified patch shapes at the landscape scale, but increased the complexity of lodgepole pine patches. Roads appeared to be a more significant agent of change than clearcuts, and roads which were more evenly distributed across a watershed had a greater effect on landscape pattern than did those which were densely clustered. Examining individual watersheds allows for the comparison of fragmentation among watersheds, as well as across the landscape as a whole. Similar studies of landscape structure in other National Forests and on other public lands may help to identify and prevent further fragmentation of these areas. 相似文献
3.
Spatial association between forest heterogeneity and breeding territory boundaries of two forest songbirds 总被引:1,自引:1,他引:0
Human activities and natural disturbances create spatial heterogeneity within forested landscapes, leading to both sharp and gradual boundaries in vegetation and abiotic attributes, such as rocks. Those boundaries may affect the detailed delineation of avian territories (independently of their general location), but their role is largely unknown. We tested, using a spatial analysis approach, whether spatial heterogeneity of vegetation and abiotic attributes were associated with territory boundaries of ten black-throated blue warblers (Dendroica caerulescens) and 14 ovenbirds (Seiurus aurocapillus). The study was conducted during summer 1999 in a mature deciduous forest near Québec City, Canada. Singing males were mapped from repeated surveys at 756 points, 25 m apart, on a 49 ha grid. Spatial heterogeneity was obtained from 27 attributes measured at each point. Boundaries of bird territories, vegetation, and abiotic attributes were delineated using the lattice-wombling boundary detection algorithm. The spatial association between territory and microhabitat boundaries was computed using the spatial overlap statistics. There was significant spatial overlap between territory boundaries and those of 15 and 17 attributes for black-throated blue warbler and ovenbird, respectively. The attributes most strongly associated with territory boundaries were conifer seedling cover, grass and total vegetation cover between 0-2 m high for black-throated blue warbler and fern cover, vegetation-covered rocks and shrub diversity for ovenbird. Complementary to this, a redundancy analysis (RDA) was used to compare attributes associated with the general occurrence of males to those whose boundaries were associated specifically with territory boundaries. Most attributes whose boundaries were associated with territory boundaries did not correspond to resource attributes, i.e., those where birds were detected most frequently. We conclude that soft boundaries associated with spatial heterogeneity may help shape forest bird territories by providing landmarks not necessarily related to resources used within territories. 相似文献
4.
Yan Boulanger Anthony R. Taylor David T. Price Dominic Cyr Elizabeth McGarrigle Werner Rammer Guillaume Sainte-Marie André Beaudoin Luc Guindon Nicolas Mansuy 《Landscape Ecology》2017,32(7):1415-1431
Context
Forest landscapes at the southern boreal forest transition zone are likely to undergo great alterations due to projected changes in regional climate.Objectives
We projected changes in forest landscapes resulting from four climate scenarios (baseline, RCP 2.6, RCP 4.5 and RCP 8.5), by simulating changes in tree growth and disturbances at the southern edge of Canada’s boreal zone.Methods
Projections were performed for four regions located on an east–west gradient using a forest landscape model (LANDIS-II) parameterized using a forest patch model (PICUS).Results
Climate-induced changes in the competitiveness of dominant tree species due to changes in potential growth, and substantial intensification of the fire regime, appear likely to combine in driving major changes in boreal forest landscapes. Resulting cumulative impacts on forest ecosystems would be manifold but key changes would include (i) a strong decrease in the biomass of the dominant boreal species, especially mid- to late-successional conifers; (ii) increases in abundance of some temperate species able to colonize disturbed areas in a warmer climate; (iii) increases in the proportions of pioneer and fire-adapted species in these landscapes and (iv) an overall decrease in productivity and total biomass. The greatest changes would occur under the RCP 8.5 radiative forcing scenario, but some impacts can be expected even with RCP 2.6.Conclusions
Western boreal forests, i.e., those bordering the prairies, are the most vulnerable because of a lack of species adapted to warmer climates and major increases in areas burned. Conservation and forest management planning within the southern boreal transition zone should consider both disturbance- and climate-induced changes in forest communities.5.
Fabiola López-Barrera Robert H. Manson Mario González-Espinosa Adrian C. Newton 《Landscape Ecology》2007,22(2):189-203
Hard (high-contrast with pastures) and soft (low-contrast with old-fields) forest edges created by slash-and-burn agriculture
have become common landscape features in regions dominated by neotropical montane forest. However, little is know about the
impacts of such edge types on forest regeneration dynamics. The consequences of varying forest edge permeability for oak acorn
dispersal were investigated in a forest mosaic in the Highlands of Chiapas, Mexico. Rates of acorn production and removal,
as well as the abundance and composition of small mammal seed consumers, were monitored along these different edge types (hard
vs. soft) at specific distances from forest edges into forest patches and adjacent grasslands during two consecutive years.
Results show that acorn removal declined significantly only in grasslands of sites characterised by hard edges (Logistic regression,
P < 0.05). Movements of metal-tagged acorns support the hypothesis that soft edges are more permeable to small mammals, with
rodents moving acorns up to 15 m into grasslands of sites with soft edges. In sites with hard edges, higher rates of acorn
dispersal were recorded from the forest edge towards the forest interior. Peromyscus spp. were the main acorn predators and/or dispersers of acorns present in our study sites. Rates of acorn removal during
a non-masting year were greater than the subsequent mast-seeding year (85% removal within 138 days vs. 75% within 213 days),
demonstrating that mast seeding may allow some seeds to escape predation. The implications of these results for oak dispersal
and regeneration along edges in fragmented tropical forest landscapes are discussed. 相似文献
6.
7.
We assessed whether forest restoration was successful in Expo ’70 Commemorative Park in Osaka Prefecture, Japan, which was planted in the 1970s with native late-successional tree species. Detailed survey and analysis of species composition, stand vertical stratification, and forest dynamics, including comparison with a reference, natural late-successional forest, were conducted. The restoration plots had grown to larger basal area compared with the reference plots, however, this was a consequence of very high densities of the overstory trees due to low self-thinning rate. Stand vertical structure of the restoration plots was biased toward overstory layers, causing high mortality of understory trees and shrubs. Because there are no mature forests near the restoration site that could act as a seed source, abundance and diversity of understory trees are likely to continue decreasing in the restoration plots, resulting in single-layered forest structure similar to those of monocultures and even-aged forests. Many seedlings of exotic species emerged in the restoration plots and this could lead to a plagiosere where exotic species dominate the vegetation inhibiting regeneration and growth of native species. Ordination analysis using different measures, basal area and abundance, showed apparently contradicting results, suggesting that multiple criteria are needed to evaluate forest restoration success. Our results indicate restoration of mature, late-successional forest cannot be achieved by simultaneous planting of native species. To sustain urban forests into the future, we must conduct long-term monitoring and management referencing natural forest structure and dynamics. 相似文献
8.
Deciduous forest and resident birds: the problem of fragmentation within a coniferous forest landscape 总被引:1,自引:1,他引:0
Six species of resident birds were censused in patches of deciduous forest within a coniferous forest landscape in south central Sweden. Here, the forests have been subjected to active forestry for a long time, but with recently increased intensity. Although the forest cover is more or less continuous in this landscape, mature deciduous forest is now a rare element compared with the untouched forest.All censused patches were similar with regards to size, proportion and amount of deciduous trees, but were either isolated in the coniferous forest (isolated patches) or near to other deciduous patches (aggregated patches). We concentrated on six species of resident birds, with moderate area requirements, that are tied to deciduous forest and whose ecology is well-known. The Nuthatch and the Marsh tit, which both show strict year-round territoriality and have a restricted dispersal phase, were significantly more likely to be found in aggregated than in isolated patches. No effect was found for the Great tit and the Blue tit, which are less territorial outside the breeding season and have a longer dispersal phase. Moreover, the Great tit is less specialized on deciduous forest than the other species. Also, the Long-tailed tit was negatively affected by isolation, which may be due to restricted dispersal and to larger area requirements of this flock-territorial species. The Hazel grouse, finally, was not affected, but this larger bird probably uses the forest in a different way from the smaller species.Our study clearly shows that fragmentation of one type of forest (deciduous) within another can have serious detrimental effects on forest-living species and raises important issues for forest management practices and conservation within a forest landscape. 相似文献
9.
Simulating the cumulative effects of multiple forest management strategies on landscape measures of forest sustainability 总被引:1,自引:2,他引:1
While the cumulative effects of the actions of multiple owners have long been recognized as critically relevant to efforts
to maintain sustainable forests at the landscape scale, few studies have addressed these effects. We used the HARVEST timber
harvest simulator to predict the cumulative effects of four owner groups (two paper companies, a state forest and non-industrial
private owners) with different management objectives on landscape pattern in an upper Michigan landscape managed primarily
for timber production. We quantified trends in landscape pattern metrics that were linked to Montreal Process indicators of
forest sustainability, and used a simple wildlife habitat model to project habitat trends. Our results showed that most trends
were considered favorable for forest sustainability, but that some were not. The proportion of all age classes and some forest
types moved closer to presettlement conditions. The trend for the size of uneven-aged patches was essentially flat while the
average size of patches of the oldest and youngest age classes increased and the size of patches of the remaining age classes
decreased. Forest fragmentation generally declined, but edge density of age classes increased. Late seral forest habitat increased
while early successional habitat declined. The owners use different management systems that cumulatively produce a diversity
of habitats. Our approach provides a tool to evaluate such cumulative effects on other landscapes owned by multiple owners.
The approach holds promise for helping landowner groups develop and evaluate cooperative strategies to improve landscape patterns
for forest sustainability. 相似文献
10.
Effects of landscape structure and forest reserve location on old-growth forest bird species in Northern Finland 总被引:4,自引:0,他引:4
Brotons Lluís Mönkkönen Mikko Huhta Esa Nikula Ari Rajasärkkä Ari 《Landscape Ecology》2003,18(4):377-393
Old-growth forest birds in Fennoscandia have sharply declined in numbers during the last decades apparently due to commercial
forest harvesting and fragmentation of old-growth forests. Conservation measures have led to the establishment of a forest
reserve network to assure the persistence of forest birds at a regional scale. However, little is known about the effects
of landscape structure within and around the reserves on the distribution of old-growth forest birds. We used a hierarchical
approach to address the questions of how landscape structure and composition within forest reserves, landscape composition
of surrounding areas and reserve location affect the abundance of resident, old-growth forest birds in the Northern Finnish
forest reserve network. The positive role of particular landscape features on bird distribution indicates that both the proportion
of old-growth forests and the structure of boreal landscape mosaic has an important role in determining the distribution of
these birds. The landscape composition surrounding the reserves proved to be only a weak predictor in species distribution
models, which argues against the primary role of the surrounding matrix in determining species distribution within forest
reserves. Reserves located near the Russian border showed a higher abundance of old-growth birds than more western ones. Once
east-west gradients in overall landscape composition had been accounted for, however, reserves did not differ significantly
in the number of species present. These results suggest that landscape gradients, rather than ecological processes such as
the presence of source areas located along the border with Russia, are the main determinant of the distribution of old-growth
forest birds in the Finnish reserve network. We propose that to enhance regional persistence of old-growth forest birds, conservation
efforts should be primarily directed towards the protection and enhancement of forest habitat quality and natural heterogeneity
of landscapes within targeted areas.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
11.
凤岗县是重点的天然林深护区,森林覆盖率达57%,因此在保护利用森林方面取得了较好的社会效益和经济效益,随着经济林木的日益扩大和发展,特别是林木病虫害防治是抓好林业产业化发展的关键所在,所以,凤岗县林业发展及病虫害预防工作,主要围绕认真贯彻执行《植物检疫条例》和《森林病虫害防治条例》,严格执行苗木"两证一签"制度,全面开展检疫、监测和防治工作,并产生了良好的社会和经济效应,本人以从事林木防治工作多年的实践谈谈以下几点: 相似文献
12.
Effects of forest regeneration on songbird movements in a managed forest landscape of Alberta,Canada
Recent studies have shown that barrier effects exist even in relatively vagile species such as forest songbirds. The objectives
of this study were to determine whether a 560 × 100 m riparian buffer strip of mature forest was used as a movement corridor
by forest songbirds and, if so, to what extent corridor effects persisted as woody vegetation regenerated in the adjacent
clearcut. Over a 4-yr period, juvenile movement rates decreased in the riparian buffer strip and increased in the regenerating
clearcut. Adult movement rates increased in the riparian buffer strip in the first year after logging, then gradually decreased,
while still increasing in the regenerating clearcut. However, both juvenile and adult movement rates were higher in the buffer
strip than in an undisturbed control site. Results suggest that most adults we captured held territories in the vicinity of
the net lanes,and that most of the juveniles captured were dispersing away from their natal territory. Four years after harvest,
juvenile movement rates were higher in the regenerating clearcut than in the riparian buffer strip, but several species had
not yet been captured or detected in the regeneration. Our results suggest that the use of the riparian buffer strip as a
movement corridor decreased with forest regeneration for both adults and juveniles. However, the buffer strip still acted
as a movement corridor for the following species: Philadelphia and Red-eyed Vireos, Red-breasted Nuthatch, and Ovenbird.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
13.
Dead wood is a critical resource for biodiversity in boreal forests. We analysed the persistence of five model species inhabiting
dead wood. By parameterising a metapopulation model (the incidence function model), the model species were all assigned characteristics
that makes it likely that they have disappeared from some (20%) forest landscapes with a long history of forest management.
In the metapopulation model, a forest stand (5 ha) was regarded as a habitat patch. The amount of habitat in each patch was
obtained from models of dead wood dynamics of Norway spruce in central Sweden. Dead wood generated by altered management over
the entire landscape was found to be less efficient in reducing extinction risks in comparison to the same amount of dead
wood generated by protecting reserves. Because generation of dead wood by altered management is often less expensive than
setting aside reserves, it is difficult to determine which conservation measure is most cost-efficient. In a landscape subjected
to forestry for the first time, it was better to preserve a few large reserves than many small ones. However, in a managed,
highly fragmented forest landscape it was better to set aside many small reserves. The reason for this was that small plots
with high habitat quality could be selected, while large reserves originally contained habitats both of high and low quality,
and the rate of habitat quality increase was low. A strategy for biodiversity conservation in a managed forest landscape should
include information about the history of the landscape, the current amount and spatial distribution of forest habitats, and
the potential for rapid restoration of forest habitats, both on managed and unmanaged forest land. 相似文献
14.
15.
The fractal shape of riparian forest patches 总被引:1,自引:0,他引:1
Remnant patches of a forest corridor were examined along the Iowa and Cedar Rivers, Iowa. A fractal dimension was found for these patches which was incorporated with the perimeter:area ratio in an index of shape. This index was then regressed on 5 hydrogeomorphic variables hypothesized to represent processes which might control patch dimensions, plus a variable to represent human impact. The hydrogeomorphic variables were derived from topographic maps; the impact variable used was the proportion of perimeter that was occupied by a road, railroad, transmission line, urban or other built area, or a straight line judged to be agricultural. Three variables remained significant in a reduced model: human impact, valley width, and stream sinuosity, but together the three accounted for only 24% of the variance in patch shape. The fractal perimeter:area ratio increased with human impact, probably because of reduced area, and decreased with valley width, which allowed more extensive forest on wide floodplains, and with sinuosity, which resulted in small patches isolated on the interior of meanders. These results indicate that in this landscape the hydrogeomorphic structures play a role, but that human impact is more significant in its effect on the shape of remnant forest patches. Other structures, such as the regional topography, may account for the unexplained variance. The index of shape used here may be useful as an independent variable in studies of ecological processes affected by patch shape and form and as a guide to conservation. 相似文献
16.
Rebecca McLain Melissa Poe Patrick T. Hurley Joyce Lecompte-Mastenbrook Marla R. Emery 《Urban Forestry & Urban Greening》2012,11(2):187-194
Over the next decades, green infrastructure initiatives such as tree planting campaigns, and ecological restoration will dramatically change the species composition, species distribution and structure of urban forests across the United States. These impending changes are accompanied by a demand for urban public spaces where people can engage in practices such as gleaning, gardening, and livestock production. This article analyzes the institutional framework that undergirds efforts in Seattle, Washington to normalize the production and use of edible landscapes. We focus attention on the role of grassroots fruit gleaning groups and highlight their bridging function between Seattle's agriculture and forestry policy arenas, creating an entry point for re-conceptualizing urban forests as sites of production. We conclude that a vision of urban forests as providers of goods as well as services may provide a more solid foundation for achieving urban sustainability than the current “hands off” approach to urban forest management. Gleaning and gathering in urban wild and cultivated landscapes provides opportunities for inhabitants to steward public natural resources and interact deeply with nature. 相似文献
17.
18.
Stephen R. Shifley Hong S. He Heike Lischke Wen J. Wang Wenchi Jin Eric J. Gustafson Jonathan R. Thompson Frank R. ThompsonIII William D. Dijak Jian Yang 《Landscape Ecology》2017,32(7):1307-1325
Context
Quantitative models of forest dynamics have followed a progression toward methods with increased detail, complexity, and spatial extent.Objectives
We highlight milestones in the development of forest dynamics models and identify future research and application opportunities.Methods
We reviewed milestones in the evolution of forest dynamics models from the 1930s to the present with emphasis on forest growth and yield models and forest landscape models We combined past trends with emerging issues to identify future needs.Results
Historically, capacity to model forest dynamics at tree, stand, and landscape scales was constrained by available data for model calibration and validation; computing capacity; model applicability to real-world problems; and ability to integrate biological, social, and economic drivers of change. As computing and data resources improved, a new class of spatially explicit forest landscape models emerged.Conclusions
We are at a point of great opportunity in development and application of forest dynamics models. Past limitations in computing capacity and in data suitable for model calibration or evaluation are becoming less restrictive. Forest landscape models, in particular, are ready to transition to a central role supporting forest management, planning, and policy decisions.Recommendations
Transitioning forest landscape models to a central role in applied decision making will require greater attention to evaluating performance; building application support staffs; expanding the included drivers of change, and incorporating metrics for social and economic inputs and outputs.19.
Adams Alison B. Pontius Jennifer Galford Gillian Gudex-Cross David 《Landscape Ecology》2019,34(10):2401-2419
Landscape Ecology - Understanding how the Northern Forest landscape has changed and is likely to change, both in terms of forest extent and forest configuration, has important implications for... 相似文献
20.
Landscape Ecology - Tree canopy connectivity is important for supporting biodiversity. In urban landscapes, empirical examinations of habitat connectivity often overlook residential land, though... 相似文献