人类干扰对甘肃麻家寺保护站鸟类群落的影响

2004年11月~2005年1月,在兴隆山麻家寺保护站的6种生境(灌木、阔叶林、混交林、针叶林、农田和人工林)中共记录鸟类25种。鸟类物种总数以灌丛和人工林最高,均为15种。阔叶林最低,为10种。鸟类多样性最高的是灌丛,最低的是阔叶林。各种生境中的鸟类组成和优势物种差异较大,建议每种生境均保持一定面积,以便保护鸟类物种多样性。     

兴隆山国家级自然保护区鸟类群落初报

通过对兴隆山自然保护区阔叶林、混交林和针叶林鸟类群落结构的调查，结果表明：混交林中鸟类物种数和鸟类物种多样性最高，阔叶林最低。其中，山雀科和鳾科在阔叶林中占优势，而柳莺亚科在混交林和针叶林中占优势。提出了保护区每种生境都应保持一定面积，以便保护该地区鸟类物种多样性的建议。     

Soil microbial biomass, abundance, and diversity in a Japanese red pine forest: first year after fire

This study was conducted to determine the microbial biomass carbon and abundance and diversity of soil microorganisms immediately after the occurrence of fire in a Japanese red pine forest, and to determine the pattern of microbial recovery within the first year after fire. The effects of fire at three slope positions were also determined. Three plots in each of the burnt and unburnt areas, measuring 10 × 10 m, were established. The first plot was located at the valley bottom, the second plot was located at the middle slope, and the third plot was located at the ridge. Analysis showed that for all parameters studied, the three plots in the unburnt area did not differ significantly and so they were treated as one control plot. The microbial biomass, abundance, and diversity structure in the unburnt and burnt plots showed significant differences. The unburnt area had the highest biomass carbon, abundance, and diversity, followed by the valley bottom, the middle slope, and then the ridge in the burnt area, and significant differences in the burnt plots were found between the valley bottom, the middle slope, and the ridge. The microbial diversity in the burnt area differed from that of the unburnt area, the microbial diversity being significantly lower in the burnt area, and the ridge was shown to have been the most affected by fire.     

Breeding bird community composition in different successional vegetation in the montane coniferous forests zone of Taiwan

To examine the relationship between forest succession following fire and the composition of bird communities, we investigated the vegetation structure, bird population density, foraging behavior and guild structure in bamboo grasslands (11 years since the last fire), pine savanna (41 years), pine woodland (58 years), old-growth hemlock forest (never burned), and old-growth spruce forest (never burned) in the Tatachia area of central Taiwan. Canopy height, total foliage cover, tree density, total basal area of tree, total basal area of snags, foliage height diversity, and tree species richness all increased with successional age. However, shrub cover peaked in intermediate successional stages. The vertical profile of foliage cover was more diverse in later successional forests, which had more breeding bird species and ecological guilds. All the breeding bird species recorded in early and intermediate stages were also found distributed in the late successional forests. Because Taiwan has high precipitation and humidity, and most forest fires in Taiwan are caused by human activities, forest fires and large areas of early successional vegetation were probably rare in the mountain areas of Taiwan prior to the arrival of humans. Therefore, bird species have not had enough time to adapt to areas with early or intermediate successional vegetation. Moreover, late successional forests host all the major plant species found in the early and intermediate stages and have higher foliage height diversity index, which was positively correlated with the bird species richness and bird species diversity index in this study. As a result, all breeding bird species and guilds in the area can be found in late successional forests. Efforts for conserving avian diversity in Taiwan should focus on protecting the remaining native old-growth forests.     

大围山国家级自然保护区自然因素对生物多样性影响的评估

大围山国家级自然保护区是云南省最重要的保护区之一,生物多样性的管理十分重要。研究对生物多样性和影响生物多样性的因子进行评估。研究所采用的第一手自然和生物多样性的第一手数据,如海拔、土壤类型、坡度、森林覆盖率、植物物种、鸟类物种等从大围山保护区的28个样点中获得。用CurveExpert统计软件对这些数据进行数理统计分析,分析的结果显示鸟类物种的多样性与植物物种的多样性呈明显的正相关,说明生境对动物区系多样性保护的关键作用。该研究还分析了关键景观特征与生物多样性的相关性,并对如何测度生物多样性和增强保护和管理该区域的生物多样性提出了建议。本研究的结果不仅对大围山自然保护区的生物多样性保护和管理策略的制定有重要的意义,而且对中国其他自然保护区的保护和管理也有积极地作用。     

Conservation value of forest plantations for bird communities in western Kenya

Tree plantations of native and exotic species are frequently used to compensate for forest loss in the tropics. However, these plantations may support lower species diversity and different communities than natural forest. We therefore investigated bird communities in stands of natural forest, different types of tree plantations and secondary forest in Kakamega Forest, western Kenya. We compared birds differing in habitat specialisation, i.e. forest specialists, generalists, and visitors. We recorded significant differences in mean species richness and number of individuals among the different forest types. Stands of natural forest and plantations of indigenous tree species comprised more species and individuals than plantations of exotic tree species and secondary forest. This was caused by a significant decline of forest specialists and generalists from natural forest and indigenous plantations to exotic plantations and secondary forest. Species composition of the bird communities did not differ between natural forest stands and plantations of a mixture of indigenous tree species, but clearly changed between natural forest and plantations of single tree species. These findings demonstrate that natural forest areas are needed for the conservation of forest bird diversity, but that plantations with a mixture of indigenous tree species can have similarly high conservation value.     

What can tree plantations do for forest birds in fragmented forest landscapes? A case study in southern Brazil

Despite the fact that tree plantations are not able to completely replace the ecological function of natural forests, the present study proposes to evaluate for which bird species or avian groups tree plantations act as habitat in fragmented landscape in southern Brazil. We compared the richness and abundance of bird species in a natural forest to adjacent plantations of Araucaria, a native tree species and of pine, an exotic plant in South America. Moreover, we evaluated the impact of tree plantations on richness of avian groups with different levels of dependence on forest habitat, feeding habits and foraging strata as well as on threatened species. The fixed 100 m radius point-counts method was used. A total of 114 bird species were recorded in all areas. Of those, 93 occurred in natural forest, 87 in Araucaria plantations and 81 in pine plantations. These results indicate that richness and abundance were lower in the pine plantations than in the natural forest and in the Araucaria plantations. Araucaria plantations can be used by a high number of bird species and their richness was not significantly lower than that observed in the adjacent natural forest. Our results suggest that Araucaria plantations could act as habitat for a large number of bird species, especially for forest-dependents species, insectivores, frugivores and species at different threat categories.     

Effect of stand age on bird communities in late-successional Macedonian pine forests in Bulgaria

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.     

Boreal bird community response to jack pine forest succession

The objective of this study was to examine bird communities in regenerating (5–25 years) and mature (40–100 years) jack pine (Pinus banksiana) forest in boreal Ontario. The study area was located near White River in north central Ontario with an area of 187,800 ha. We explored the response of bird community structure to stand age, and the influence of stand age on the distribution of individual species. We were interested in two principal questions. The first was how unique are the bird communities to specific age classes. If bird communities are highly specific to age classes then alterations to the age class distribution of the forest can have important impacts on the overall bird community composition and structure. The second question was how specific are individual species to age classes. Species that are highly specific to a single age class are expected to be highly sensitive to the amount and potentially the configuration of that age class on the landscape. We sampled birds for three breeding seasons. The number of bird species increased with stand age. Tree species composition did not change as stands aged, but there were distinctive changes in vegetation structure through succession. For example, the total amount of vertical vegetation structure increased significantly with age. More than half of the bird species examined were significant indicators of individual age classes. Blue-headed vireo, brown creeper, black-throated green warbler, golden-crowned kinglet, ovenbird and red-breasted nuthatch were all significant indicators of the mature age class. The bird assemblage of mature stands was significantly different from that of regenerating forest and within regenerating forest, 3–5-year-old stands contained a significantly different bird assemblage to that of 8–25-year-old regenerating forest. These results suggest that the distribution of forest age classes on the landscape is a critical element in determining habitat availability and therefore the viability of boreal bird populations in managed forests.     

Predicting breeding bird occurrence by stand- and microhabitat-scale features in even-aged stands in the Central Appalachians

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.     

Moving riparian management guidelines towards a natural disturbance model: An example using boreal riparian and shoreline forest bird communities

Forest harvesting strategies that approximate natural disturbances have been proposed as a means of maintaining natural species’ diversity and richness in the boreal forests of North America. Natural disturbances impact shoreline forests and upland areas at similar rates. However, shoreline forests are generally protected from harvest through the retention of treed buffer strips. We examined bird community responses to forest management guidelines intended to approximate shoreline forest fires by comparing bird community structure in early (1–4 years) post-burned and harvested boreal riparian habitats and the adjacent shoreline forest. We sampled riparian areas with adjacent: (1) burned merchantable shoreline forest (n = 21), (2) burned non-merchantable shoreline forest (n = 29), (3) 10 m treed buffer with 25% retention in the next 30 m (n = 18), and (4) 30 m treed buffer (n = 21). Only minor differences were detected in riparian species’ abundance and bird community composition between treatments with greater differences in these parameters occurring between post-fire and post-harvest upland bird communities. Indicators of all merchantable treatments were dominated by upland species with open-habitat species and habitat generalists being typical upland indicator species of burned merchantable habitats and forest specialists typical upland indicators of harvested treatments. Riparian species indicative of burned riparian habitats were Common Yellowthroat (Geothlypis trichas), Le Conte’s Sparrow (Ammodramus leconteii) and Eastern Kingbird (Tyrannus tyrannus) and indicators of 30 m buffers were Alder Flycatcher (Empidonax alnorum) and Wilson’s Warbler (Wilsonia pusilla). Multivariate Redundancy Analysis (RDA) of the overall (riparian and upland birds) community showed greater divergence than RDA with only riparian species suggesting less effect of fire and forestry on riparian birds than on upland birds. Higher natural range of variability (NRV) of overall post-fire bird communities compared to post-harvest communities emphasizes that harvesting guidelines currently do not achieve this level of variability. However, lack of a large negative effect on common riparian species in the first 4 years post-disturbance allows for the exploration of alternative shoreline forest management that better incorporates bird community composition of post-fire riparian areas and shoreline forests.     

Effects of fire disturbance on bird communities and species of mountain Serrano forest in central Argentina

In central Argentina, Serrano forest has a long history of fire disturbance; however, the impact of fire on avifauna remains unknown. We compared the avian–habitat relationships in forest patches with low, moderate, and high fire regimes using a community-level (species richness, abundance, ordination and guilds) and species-level (indicator species analysis) approach. In patches under each fire condition, we recorded bird community composition, richness and abundance, and different vegetation structure variables. The site under high-severity fire regime was structurally poor and had been converted from original forest to dense grassland. There, diversity of bird community was low, retaining approximately 30 % of the species present in the least impacted site. Avian assemblage was dominated by generalist and open area birds. Guilds were underrepresented, showing an important reduction of foliage granivorous, nectarivorous, omnivores, and foliage and bark insectivorous, and absence of fly-catchers. Moreover, low abundance of forest understory, midstory, and canopy species and of birds belonging to open and closed nesting guilds was detected. By contrast, under low and moderate-severity fire regimes highest bird diversity as well as highest representativeness of most guilds was observed. Forest bird species were strongly associated with low fire disturbance, whereas moderate fire disturbance was characterized by the presence of forest and generalist species. Given the critical conservation status of Serrano forest in Córdoba, Argentina, habitat restoration and protection of forest relicts could be suitable measures to promote avifauna preservation.     

Effect of forest shape on habitat selection of birds in a plantation-dominant landscape across seasons: comparison between continuous and strip forests

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.     

Hurricane Katrina impacts the breeding bird community in a bottomland hardwood forest of the Pearl River basin, Louisiana

We monitored breeding bird communities and vegetation both before and after Hurricane Katrina category 2 winds severely damaged extensive bottomland hardwood forest of the Pearl River basin, south Louisiana. Many trees were felled by wind, most others were stripped of leaves and branches, and the canopy opened considerably (57%). Blackberry thickets sprouted and expanded to cover almost all of what was previously a patchily open forest understory. The bird community changed distinctively following the hurricane, driven primarily by increased density of species that prefer dense understory (regenerating) habitat. Individual species that increased significantly in density included one year-round resident, Carolina wren, and five breeding migrants, white-eyed vireo, Swainson's warbler, Kentucky warbler, hooded warbler, and yellow-breasted chat. These patterns were predictable responses to the opened canopy and increased density of understory vegetation. However, over three years following the storm, most species, especially canopy breeders, showed no distinct numerical response to the hurricane, which suggests that the initial bird community was resistant to hurricane disturbance. Only one species, Acadian flycatcher, declined significantly after the hurricane, presumably because of loss of its preferred open understory breeding and feeding habitat. Our results thus document and reinforce the important role hurricanes play along the Gulf coast in structuring forest bird communities by altering understory habitat. We expect habitat changes will continue as invasive plant species further change forest community structure, and as large storms increase in frequency in relation to global climate change. Thus, we also expect continued changes to the bird community, which may include additional future declines.     

Change in avian abundance predicted from regional forest inventory data

An inability to predict population response to future habitat projections is a shortcoming in bird conservation planning. We sought to predict avian response to projections of future forest conditions that were developed from nationwide forest surveys within the Forest Inventory and Analysis (FIA) program. To accomplish this, we evaluated the historical relationship between silvicolous bird populations and FIA-derived forest conditions within 25 ecoregions that comprise the southeastern United States. We aggregated forest area by forest ownership, forest type, and tree size-class categories in county-based ecoregions for 5 time periods spanning 1963–2008. We assessed the relationship of forest data with contemporaneous indices of abundance for 24 silvicolous bird species that were obtained from Breeding Bird Surveys. Relationships between bird abundance and forest inventory data for 18 species were deemed sufficient as predictive models. We used these empirically derived relationships between regional forest conditions and bird populations to predict relative changes in abundance of these species within ecoregions that are anticipated to coincide with projected changes in forest variables through 2040. Predicted abundances of these 18 species are expected to remain relatively stable in over a quarter (27%) of the ecoregions. However, change in forest area and redistribution of forest types will likely result in changed abundance of some species within many ecosystems. For example, abundances of 11 species, including pine warbler (Dendroica pinus), brown-headed nuthatch (Sitta pusilla), and chuck-wills-widow (Caprimulgus carolinensis), are projected to increase within more ecoregions than ecoregions where they will decrease. For 6 other species, such as blue-winged warbler (Vermivora pinus), Carolina wren (Thryothorus ludovicianus), and indigo bunting (Passerina cyanea), we projected abundances will decrease within more ecoregions than ecoregions where they will increase.     

Avian population and community processes in forest ecosystems: Long-term research in the Hubbard Brook Experimental Forest

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.     

Effects of management regime on the abundance and nest survival of shrubland birds in wildlife openings in northern New England, USA

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.     

东莞常平旗岭森林公园植物景观规划和配置初探

以森林生态原则为基础,遵循现代林业理论,根据树种的生态特性,从森林美学的角度对广东东莞常平旗岭森林公园进行植物配置与植物景观规划。对坡度大、植物生长环境较差的区位进行封山育林,使其自然生长与更新;对裸露的废弃石场采取复绿措施;对面积较大和林相较单一的桉树林和相思林,选择生长快的乡土树种,并配置少量红叶树种进行改造,以改善林间生态环境,增添景观效果。根据植物花期不同选择开花树种进行改造,打造四季有花的森林公园。根据道路使用功能的不同配置树种,以追求森林公园生态和社会效益的最大化。     

Importance of forest structure versus floristics to composition of avian assemblages in tropical deciduous forests of Central Highlands,India

We investigated how much forest structure and floristics independently contributed to the composition of avian assemblages at multiple scales and for individual foraging guilds in tropical deciduous forests of Central Highlands, India. We derived dissimilarity matrices between all pairs of the 36 sampling sites with respect to forest structure, floristics, and bird species composition and ran Mantel's randomization tests to detect significant associations among the matrices after partialling out the effect of geographic distance between sites. Bird species composition was found to be significantly related to forest structure across habitats, and floristics within the moist-deciduous forests. This finding is consistent with earlier observations that birds respond, in their species composition, to vegetation structure across habitats and to vegetation composition within a habitat. As predicted, the composition of insectivorous birds was influenced by forest structure, but the phytophagous guild did not show any relation to vegetation composition in contrast to patterns observed elsewhere. We explain this anomaly as a result of availability of a wide choice of food plants for phytophagous birds in central Indian tropical forests and weak species–environment relationships on account of their nomadism. Extraction of non-timber forest products remains a key economic activity in central India and our results imply that it can potentially influence the composition of forest bird communities through alteration of forest structure and floristics.