共查询到20条相似文献，搜索用时 15 毫秒
1.
Richard B. Chandler David I. King Carlin C. Chandler 《Forest Ecology and Management》2009,258(7):1669-1676
Many shrubland bird species are declining in eastern North America and as a result forest managers have used a variety of techniques to provide breeding habitat for these species. The maintenance of permanent “wildlife openings” using prescribed burns or mechanical treatments is a widely used approach for providing habitat for these species, but there have been no studies of the effects of treatment regime on bird abundance and nest survival in managed wildlife openings. We studied shrubland birds in wildlife openings on the White Mountain National Forest (WMNF) in New Hampshire and Maine, USA, during 2003 and 2004. We analyzed bird abundance and nest survival in relation to treatment type (burned versus mowed), treatment frequency, time since treatment, and patch area. We found that wildlife openings provided habitat for shrubland birds that are not present in mature forest. There was relatively modest support for models of focal bird species abundance as a function of treatment regime variables, despite pronounced effects of treatment on habitat conditions. This probably was attributable to the combined effects of complex site histories and bird site fidelity. Overall nest success (52%) was comparable to other types of early-successional habitats in the region, but there were few supported relationships between nest survival and treatment variables. We conclude that wildlife openings provide quality habitat for shrubland birds of high conservation interest as long as managers ensure treatment intervals are long enough to permit the development of woody vegetation characteristic of the later stages of this sere. Also, wildlife openings should be large enough to accommodate the territory sizes of all target species, which was ≥1.2 ha in this study. 相似文献
2.
David I. King Scott SchlossbergRobert T. Brooks Michael E. Akresh 《Forest Ecology and Management》2011,261(1):10-18
Fire-dependent ecosystems include some of the most threatened ecosystems in the world, and where fuels are allowed to accumulate, they can present significant threats to human life and property. Fuel reduction activities can be effective in reducing the risk of wildfire, but these practices need to be evaluated relative to their effect on biodiversity. We surveyed birds in an inland pitch pine-scrub oak barren, a fire-dependent plant community, in which fuel reduction had been carried out via thinning of canopy trees to reduce the risk of running crown fires. We hypothesized that thinning pitch pine forest would negatively affect the abundance of mature forest birds and positively affect the abundance of scrub-shrub birds. Our results confirmed these expectations: several mature forest bird species were less abundant in thinned pitch pine than unthinned pitch pine, although most of these species were also present in mixed deciduous forest, and therefore regionally well represented. In contrast, another group of bird species was scarce or absent from unthinned pitch pine and mixed deciduous forest, but present in thinned sites and scrub oak stands. These were scrub-shrub species that do not nest in mixed deciduous or pitch pine forest but depend on shrubland or savannah habitats that cover ∼3% of the region. We conclude that fuel reduction by thinning canopy trees at this site provides habitat for high-priority scrub-shrub bird species at the cost of modest reductions in numbers of forest birds whose regional aggregate population is large. 相似文献
3.
Early successional birds have declined in the northeastern United States due to the regeneration of forest on abandoned farm fields and the suppression of natural disturbances that once provided appropriate habitat. These species have become increasingly dependent on early successional habitats generated by such activities as timber harvesting. Recent approaches of timber harvesting, which range from single-tree harvesting to clearcutting, create forest openings of different sizes and configurations embedded in landscapes with different land use patterns. To assess the importance of forest openings created by timber harvesting for shrubland birds, we surveyed birds on 50 m radius plots in 34 harvest sites (0.5–21 ha). We collected data on multi-scaled habitat variables ranging from plot-level vegetation characteristics to land use patterns within 1 km of each study site. We also monitored mating and nesting success of Blue-winged Warblers (Vermivora pinus) in 10 forest openings.
The abundance of most shrubland species was influenced by plot-level habitat variables, such as tree density and vegetation height, rather than shrubland area or the composition of land uses in the surrounding landscape. Only Eastern Towhees (Pipilo erythrophthalmus) were more frequent in survey plots in larger forest openings. In contrast, neither abundance nor reproductive activity of Blue-winged Warblers was correlated with the size of the forest opening. Their abundance was negatively related to vegetation height, however. Only 54% of the territorial male Blue-winged Warblers in forest openings were mated. We documented relatively low nest success rates of 21.1% during the egg laying and incubation nest stages, but increased success rates during the later stages of nesting.
Our results indicate that even small forest openings with low vegetation provide habitat for Blue-winged Warblers and other shrubland birds. The overall reproductive rate of territorial male Blue-winged Warblers in forests openings was low during the 2 years of the study, however. Further studies are needed to assess the long-term value of this type of habitat for sustaining shrubland bird populations. 相似文献
4.
Avian use of even-aged timber harvests is likely affected by stand attributes such as size, amount of edge, and retained basal area, all characteristics that can easily be manipulated in timber harvesting plans. However, few studies have examined their effects during the post-breeding period. We studied the impacts of clearcut, low-leave two-age, and high-leave two-age harvesting on post-breeding birds using transect sampling and mist-netting in north-central West Virginia. In our approach, we studied the effects of these harvest types as well as stand size and edge on species characteristic of both early-successional and mature forest habitats. In 2005-2006, 13 stands ranging from 4 to 10 years post-harvest and 4-21 ha in size were sampled from late June through mid-August. Capture rates and relative abundance were similar among treatments for generalist birds. Early-successional birds had the lowest capture rates and fewer species (∼30% lower), and late-successional birds reached their highest abundance and species totals (double the other treatments) in high-leave two-age stands. Area sensitivity was evident for all breeding habitat groups. Both generalist and late-successional bird captures were negatively related to stand size, but these groups showed no clear edge effects. Mean relative abundance decreased to nearly zero for the latter group in the largest stands. In contrast, early-successional species tended to use stand interiors more often and responded positively to stand size. Capture rates for this group tripled as stand size increased from 4 to 21 ha. Few birds in the forest periphery responded to harvest edge types despite within-stand edge effects evident for several species. To create suitable habitat for early-successional birds, large, non-linear openings with a low retained basal area are ideal, while smaller harvests and increased residual tree retention would provide habitat for more late-successional birds post-breeding. Although our study has identified habitat use patterns for different species in timber harvests, understanding habitat-specific bird survival is needed to help determine the quality of silvicultural harvests for post-breeding birds. 相似文献
5.
Group-selection is a widely used silvicultural technique, and although recent studies have compared the ecology of birds inhabiting patches of regenerating forest created by group-selection with that of birds in clearcuts, little is known about the effect of opening size and shape on the ecology of early-successional shrubland birds within stands treated with group-selection. We studied chestnut-sided warblers (Dendroica pensylvanica), which are an early-successional shrubland bird, nesting in 29 patches of regenerating (4–5 years old) northern hardwoods forest 0.15–0.69 ha in area to determine whether the ecology of this species is affected by patch size or shape. Chestnut-sided warbler density decreased with patch size, however nests were initiated earlier in larger patches. There were no relationships between patch area and number of young fledged per territory or nest predation rates. Similarly, there were no relationships between patch shape (defined as the ratio of the patch perimeter to the perimeter of a circle of the same area) and territory density, date of initiation of first nests, number of young fledged per territory, or nest predation rates. These results contrast with the results of studies of area sensitivity of mature forest and grassland birds, in which bird density is negatively related to patch area. However, later nest initiation in smaller patches suggests that smaller patches are lower quality habitat, which is consistent with the negative relationships between patch area and habitat quality reported in studies of birds nesting in patches of mature forest. 相似文献
6.
Although intensively managed pine forests are common in the southeastern US, few studies describe how combinations of mechanical (MSP) and chemical site preparation (CSP) and herbaceous weed control (HWC) techniques affect bird communities that use early successional habitats within young pine forests. Therefore, we examined effects of six treatments of increasing management intensity via combinations of MSP (strip-shear and wide spacing or roller chop and narrow spacing) and CSP (application or no application) treatments with banded or broadcast HWC on bird communities in six loblolly pine (Pinus taeda) plantations in the Coastal Plain of North Carolina, USA, for 8 years following site preparation. Wide pine spacing and strip-shear MSP increased bird abundance and species richness over narrow spacing and chopped MSP for 6 years after planting. Chemical SP reduced bird abundance in year 2, increased bird abundance in year 6, had no effect on abundance after year 7, and did not affect species richness in any year. Total bird abundance and species richness were similar between banded and broadcast HWC. Site preparation and HWC had no effect on bird diversity and bird communities were most similar in treatments of similar intensity. Site preparation and HWC had few or no effects on birds based upon migratory status, habitat association, or conservation value. The addition of chemical site preparation or HWC had little effect on birds beyond pine spacing, and bird abundance was not proportional to management intensity. Although we observed treatment effects, all treatments provided habitat used by a variety of bird species, and pine plantations may play an increasingly important role in bird conservation as forests become fragmented and converted to other land uses and as natural processes that create early successional habitat, such as fire, are suppressed. 相似文献
7.
Spatial scale is an important consideration when managing forest wildlife habitat, and models can be used to improve our understanding of these habitats at relevant scales. Our objectives were to determine whether stand- or microhabitat-scale variables better predicted bird metrics (diversity, species presence, and abundance) and to examine breeding bird response to clearcut size and age in a highly forested landscape. In 2004-2007, vegetation data were collected from 62 even-aged stands that were 3.6-34.6 ha in size and harvested in 1963-1990 on the Monongahela National Forest, WV, USA. In 2005-2007, we also surveyed birds at vegetation plots. We used classification and regression trees to model breeding bird habitat use with a suite of stand and microhabitat variables. Among stand variables, elevation, stand age, and stand size were most commonly retained as important variables in guild and species models. Among microhabitat variables, medium-sized tree density and tree species diversity most commonly predicted bird presence or abundance. Early successional and generalist bird presence, abundance, and diversity were better predicted by microhabitat variables than stand variables. Thus, more intensive field sampling may be required to predict habitat use for these species, and management may be needed at a finer scale. Conversely, stand-level variables had greater utility in predicting late-successional species occurrence and abundance; thus management decisions and modeling at this scale may be suitable in areas with a uniform landscape, such as our study area. Our study suggests that late-successional breeding bird diversity can be maximized long-term by including harvests >10 ha in size into our study area and by increasing tree diversity. Some harvesting will need to be incorporated regularly, because after 15 years, the study stands did not provide habitat for most early successional breeding specialists. 相似文献
8.
《Forest Ecology and Management》2007,238(1-3):375-383
Increasingly, regional conservation plans are using information about how animals respond to changes in habitat characteristics to provide guidelines for management. However, the ability of these plans to effectively guide management remains largely untested. To test a regional bird conservation plan developed by Partners in Flight, we compared bird abundance in untreated stands to that of stands where shrub cover had been reduced to lower the risk of fire. We used these data to evaluate whether birds identified as focal species in the conservation plan increased or decreased in abundance as a result of the treatments. Over a two-year period, two of 12 Partners in Flight oak woodland and chaparral focal species were more abundant at treated units in both years; no species were consistently less abundant at treated units in both years. These results suggest small-scale (7–42 ha) treatments are consistent with the objectives identified in the Partners in Flight regional conservation plan because they benefited species associated with edges, but did not have negative effects on shrub-associated species. We suggest that this is a result of the small size of treatments and the retention of shrub patches in treated areas. An alternative explanation is that the bird/habitat relationships used to develop the conservation plans do not apply in this study area. We tested this hypothesis by comparing the correlations between habitat characteristics and bird abundance with the information in the conservation plans. In all but one case, the direction of the correlation agreed with information in the conservation plan. This project illustrates that even though the ability of conservation plans to predict the ecological effects of management activities may be limited, they can play an important role in interpreting the results of ecological monitoring. 相似文献
9.
Forest managers often seek to balance economic benefits from timber harvesting with maintenance of habitat for wildlife, ecosystem function, and human uses. Most research on the relationship between avian abundance and active timber management has been short-term, lasting one to two years, creating the need to investigate long-term avian responses and to identify harvest thresholds when a small change in habitat results in a disproportionate response in relative abundance and nest success. Our objectives were to identify trends in relative abundance and nest success and to identify landscape-scale disturbance thresholds for avian species and habitat guilds in response to a variety of harvest treatments (clear-cuts, heavy and light partial harvests) over 14 years. We conducted point counts and monitored nests at an industrial forest in the central Appalachians of West Virginia during 1996-1998, 2001-2003, and 2007-2009. Early successional species increased in relative abundance across all three time periods, whereas interior-edge and forest-interior guilds peaked in relative abundance mid-study after which the forest-interior guild declined. Of 41 species with >10 detections, four (10%) declined significantly, 13 (32%) increased significantly (only three species among all periods), and 9 (22%) peaked in abundance mid-study (over the entire study period, four species had no significant change in abundance, four declined, and one increased). Based on piecewise linear models, forest-interior and interior-edge guilds’ relative abundance harvest thresholds were 28% total harvests (all harvests combined), 10% clear-cut harvests, and 18% light partial harvests, after which abundances declined. Harvest thresholds for the early successional guild were 42% total harvests, 11% clear-cut harvest, and 10% light partial harvests, and relative abundances increased after surpassing thresholds albeit at a reduced rate of increase after the clear-cut threshold. Threshold confidence intervals for individual species overlapped their guild threshold intervals 91% of the time. Even though relative abundance of most species (80%) did not decline as the area affected by timber management increased, implementing management at or below our approximate forest-interior and interior-edge harvest thresholds would reduce the number of declining species by half, maintain higher relative abundances of four species with a net decline in abundance but that peaked in abundance mid-study, and maintain higher relative abundances of ten additional species. In contrast, this management strategy also would prevent the increase in relative abundance of seven species and limit the increase in abundance of three species that increased throughout the study. 相似文献
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12.
We investigated whether partial cutting used to mimic small-scale natural disturbances could maintain cavity and bark nesting breeding birds. We assessed changes in the relative abundance of cavity nesting birds in two intensities of partial cutting, compared to uncut and clearcut stands, 9 years post-treatment. We then examined the relationship between forest structure and nesting abundance (stand scale) and compared characteristics of used nest and forage trees to unused trees (tree scale). The relative abundance of most species was highest in either heavy removal or light removal treatments 9 years post-harvest. Brown creepers were most abundant in uncut, and red-breasted sapsuckers were most abundant in clearcut and heavy removal treatments. The proportion of deciduous trees and the density of dead trees were the best predictors of nest abundance. Individual nest tree use was predicted by the presence of large deciduous trees with broken tops and early to advanced stages of decay. Forage tree use was predicted by the presence of large conifer trees in advanced stages of decay. To maintain breeding habitat for cavity nesters, we suggest that forest managers retain the specific structural attributes required for nesting, but also the diverse forest conditions required for foraging. 相似文献
13.
Field margin vegetation is among the last vestiges of semi-natural habitat for birds in many agricultural landscapes of tropical regions. However, field margins differ in size, structure, and flora, and their value to birds depends on all these factors and on species-specific habitat preferences. Therefore, we analyzed data on resident and neotropical migratory birds found in 40 field margins of the agricultural landscape of El Bajío, Guanajuato, Mexico. The structural and botanical characteristics of the field margin, and those of the adjacent landscape, were related to bird species richness and abundance. We recorded 61 species of birds of which 36 were migratory. Locally, the size of the field margin (width, height, volume), its vegetative vertical complexity, and the abundance of trees and tree species had a positive effect on bird species richness and abundance. Native trees, especially mesquites, were especially important for many birds observed foraging, nesting, and perching. The most important landscape-scale variables were the density of hedgerows around field margins and the distance to natural vegetation remnants (scrub forest). Bird species richness and abundance were positively affected by the length of the hedgerows within 100 and 200-m-radius circles centered on each field margin. Field margins closer to natural vegetation also had more bird species and individuals. On the basis of our results, we suggest some general management recommendations for improving the habitat for birds in tropical agricultural landscapes. 相似文献
14.
《Forest Ecology and Management》2006,233(1):176-191
Unmanaged cedar (Thuja plicata)-hemlock (Tsuga heterophylla) forests of the northern Interior Wetbelt of British Columbia support standing and dead trees with a variety of structural features that provide habitat for wildlife. We describe the pre-harvest abundance and characteristics of wildlife trees (standing trees with special characteristics that provide habitat for wildlife) and coarse woody debris (CWD) at three silvicultural systems trials in cedar-dominated stands, and the short-term effects of forest harvesting on the abundance and attributes of CWD. The treatments were clearcut, group retention (70% volume removal), group selection (30% volume removal), and unlogged control. We measured standing trees in 75 0.125-ha plots and CWD along 225 24-m transects, using a functional classification system to characterize habitat attributes of trees and logs. CWD assessments were repeated on the same transects after the harvest. The relationship between tree size and occurrence of habitat features was strong for both standing trees and logs. Each of the four major tree species in the study area was associated with specific habitat features that occurred more often in that species than in any other. Large concealed spaces at the bases of trees, providing den sites and escape cover, were associated with hybrid white spruce (Picea engelmannii × glauca). We suggest that these trees had originated on nurse logs that subsequently rotted away; if that supposition is correct, there may be shortages of these structures in future stands that originate from plantations. Forest harvesting had little effect on the volume of CWD, but did affect the decay class distribution, reduce the proportion of pieces having structural habitat attributes, and reduce piece lengths; these effects were generally proportional to the level of harvest removal. Partial-cut silvicultural systems have the potential to mitigate anticipated deficits in large wildlife trees and logs in managed stands, if components of the stand are managed on longer rotations than those planned for timber production alone. 相似文献
15.
Tana M. EllisMatthew G. Betts 《Forest Ecology and Management》2011,261(8):1372-1381
The extensive removal of competing broadleaved shrubs in forest plantations typically results in structural and compositional simplification of early seral habitat. However, information on the tradeoffs between such intensive forestry practices and biodiversity is scant. Here we assess the magnitude and direction of potential impacts of intensive forest management on populations of early seral-associated breeding birds. Observed population declines of several Neotropical migrant bird species are hypothesized to be linked to the loss of early seral habitat on the breeding grounds. We investigated the association between broadleaved hardwood cover and avian abundance and diversity in intensively managed early seral Douglas-fir (Pseudotsuga menziesii) stands of the Pacific Northwest. Bird species richness decreased across an elevational gradient, but did not vary as a function of either local vegetation composition or structure. In contrast, bird abundance was strongly associated with hardwood cover at local and landscape scales, especially for foliage-gleaning species. We found strong support for the existence of a threshold in relative bird abundance as a function of hardwood at the stand scale; abundance doubled with an increase from 1% to ∼6% hardwood and then reached a plateau. Though abundance of leaf-gleaners increased even more strongly across a gradient in hardwood cover, evidence for a distinct threshold was less clear. We conclude that when early seral hardwood forest is scarce, even small increases in hardwood may provide substantial conservation benefits. However, for some species (i.e., foliage gleaners), there may be more direct trade-offs in abundance and juvenile recruitment with hardwood management intensity. 相似文献
16.
Richard T. Holmes 《Forest Ecology and Management》2011,262(1):20-32
Long-term studies in relatively undisturbed forest ecosystems, such as occur in many of the USFS’ Experimental Forests, provide valuable insight into bird population and community processes, information pertinent to forest management and bird conservation. Major findings from 40 years of research in the Hubbard Brook Experimental Forest in north-central New Hampshire reviewed here show that the distributions and abundances of bird species are dynamic, even within well-developed and mature forests, and that species respond differently to habitat (vegetation) structure, food availability, and other features of the forest environment. At the local scale, bird population demography is most affected by factors that influence fecundity and recruitment, mainly food availability, weather, nest predators, and density dependent processes. Fecundity is strongly correlated with subsequent recruitment and is critical for maintaining breeding population size. Events in the non-breeding season, however, also influence the abundance and demography of breeding populations, indicating the need to assess factors operating throughout the species’ annual cycle. At the landscape scale, populations in temperate forests are spatially structured by each species’ response to habitat and environmental patterns, but also by social interactions such as competition and conspecific attraction. Settlement patterns and ultimately reproductive performance depend on habitat quality, based on vegetation structure, food availability and nest predator effects that vary across the landscape. Results from these long-term studies centered at Hubbard Brook provide a mechanistic understanding of avian population dynamics and community responses. The results provide a framework for predicting how future changes in habitat quality, climate, and other environmental threats may influence bird populations and communities in north-temperate forests. 相似文献
17.
Sara A. Berges Lisa A. Schulte Moore Thomas M. Isenhart Richard C. Schultz 《Agroforestry Systems》2010,79(1):97-110
In response to concern about the loss of ecosystem services once provided by natural riparian systems, state and federal agencies
have established incentive programs for landowners to convert sensitive lands from agricultural to conservation uses. Enhancement
of wildlife habitat, while identified as a function of such systems, has often been of secondary importance to soil conservation
and water quality objectives. Though greatly important, little consideration has been given to how specific species will respond
to the design and management of riparian buffers or other conservation lands. This study compared avian communities within
a chronosequence of riparian buffers established on previously cropped or pastured land with those of the nearby matrix land
cover types (row crop fields and an intensively grazed pasture). The riparian buffers consisted of native grasses, forbs,
and woody vegetation established at three different times (2, 9, and 14+ years prior to survey). At each site, 10 min point
counts for breeding birds were conducted using 50 m fixed radius plots, which were visited eight times between May 15 and
July 10, 2008. A total of 54 bird species were observed over all of the study sites. The re-established riparian buffers in
this study had higher bird abundance, richness, and diversity than the crop and pasture sites. These results suggest that
re-establishing native riparian vegetation in areas of intensive agriculture will provide habitat for a broad suite of bird
species, but that specific species will reflect successional stage, horizontal and vertical vegetative structure, and compositional
diversity of the buffer vegetation. These results emphasize the importance of matching buffer design and management to species
requirements if the objectives are to attract specific target species or species groups. 相似文献
18.
Conversion of natural forests to other land use results not only in a decrease of forest area but also in the degradation
of remnant forests as a habitat for forest animals. Although such degradation due to an increase of forest edges has been
studied most intensively, other factors such as forest shape may also contribute to the degradation. In this study, we compared
bird abundance and species richness between irregular-shaped and relatively continuous forests in the breeding and migratory
seasons. Since the forests were surrounded by tree plantations rather than open lands, the edge effect may have been weak
at the study site. Our results suggested that the irregular forest shape negatively affected forest bird abundance and species
richness in the breeding season, but not in the migratory season. The response of birds varied with bird traits: migrants
avoided the irregular-shaped forest, but residents did not. Among the residents, small ones preferred or tolerate the irregular-shaped
forest whereas large ones avoided it. This study indicates that careful consideration of various factors such as seasonality
and bird traits is needed to understand the consequences of land use changes on forest birds. 相似文献
19.
Conservation organizations in the northeastern United States (US) recommend forest clearcutting to create shrubland habitat, which is required by many wildlife species with declining populations. The planning of habitat management programs is hampered by a lack of information on the current extent of shrubland habitat and the current rate of forest clearcutting that creates shrubland habitat. We addressed these information gaps by using a combination of automated and manual approaches to determine the extent and spatial configuration of shrubland habitat and recent forest clearcuts. We focused on the state of Rhode Island because (a) it is representative of the northeastern US in terms of the prevalence of private ownership of forests, and the ongoing decline in the populations of many shrubland wildlife species; (b) federal, state and private conservation groups are actively promoting clearcuts to create shrubland habitat; (c) many state-wide GIS databases are available; and (d) the spatial extent of the state made our results both generalizable and politically relevant. Our fine-scale mapping allowed a detailed analysis of shrubland distribution in conjunction with other available GIS layers that facilitates identification of priority areas for habitat management. We found that the extent of upland shrubland in non-coastal areas is decreasing by at least 1.5% annually. Considering the lack of consensus about conservation targets for the amount of shrubland, we propose that conservation organizations attempt to stabilize rather than expand the extent of shrubland habitat. This approach would provide an opportunity to assess whether the current extent of shrubland is sufficient to maintain reduced but stable wildlife populations that require this habitat. We propose a coordinated forest management program with targets for increased forest management on conservation lands. We found that the average patch size of shrubland created by recent clearcuts is large enough for most shrubland bird species, but too small for the New England cottontail (Sylvilagus transitionalis), which has been proposed for threatened and endangered status. 相似文献
20.
To gain insight into the question of which vegetation characteristics have the most influence on avian assemblages in late-successional forests, the habitat preferences of bird-guilds in old-growth endemic forests of Macedonian pine were studied over 3 years in the Pirin National Park, Bulgaria. Bird–habitat relationships were investigated by comparing vegetation characteristics, and bird species richness, diversity, abundance, and guild structure of birds (determined according to food type, foraging and nesting sites) between mature (60–100 years old) and over-mature (>120 years old) Macedonian pine forest stands. Studied forest age-classes differed mainly by the density, height and diameter of trees, and the amount of dead wood. The first one of these parameters decreased and the latter two parameters increased with the forest succession. The difference in the vegetation structure affected the abundance of bird-guilds and thus, the overall bird abundance and the structure of avian assemblages within Macedonian pine forests. There was no significant difference in bird diversity among studied forest age-classes, but the overall bird abundance increased with forest maturation. Analyzed by study plots, species richness was higher in over-mature forests, but at cluster level, there was no significant difference between mature and over-mature forest age-classes. Half of the studied (insectivorous, hole- and ground-nesters, bark- and canopy-foraging bird species) guilds were more abundant in over-mature forests, while there was no bird-guild exhibiting a preference for mature forest stands. The abundances of bird-guilds were correlated with tree height, diameter at breast height and the amount of dead wood between the studied forest age-classes and this might explain their preferences for over-mature pine forests. Therefore, for future sustainable management of these endemic forests and the conservation of their avifauna, efforts should focus on protecting the remaining native old-growth forest stands and the importance of the structure of Macedonian pine forests on their bird assemblages should be considered in forestry practices. 相似文献