西天目山低山地区人工与自然生境夏季鸟类群落比较

为了研究西天目山低山地区人类活动对鸟类群落的影响,于2007年7月对该地区两种自然生境(常绿乔木林和灌丛)与两种人工生境(苗圃和公园)中鸟类的种类、数量及鸟类群落的相似性进行比较.结果表明,常绿乔木林与灌丛中的鸟类物种数最多,常绿乔木林中的鸟类密度显著高于灌丛中的鸟类密度.苗圃和公园中鸟类物种数及密度都显著低于常绿乔木林和灌丛.两种人工生境中鸟类群落相似性最高,广性分布物种是这两种生境中鸟类群落的主要组成部分,而狭性分布物种仅在常绿乔木林和灌丛中分布.以上结果表明,人类活动所造成的生境改变对鸟类多样性有不利影响.     

鸟类调查的样线法和样点法比较:以崇明东滩春季盐沼鸟类调查为例

为了探讨样线法和样点法对盐沼湿地鸟类调查的有效性及适用性, 我们于2008年3–5月采用固定距离样线法和固定半径样点法对崇明东滩盐沼鸟类进行了调查。5次调查共记录到鸟类24种, 其中样线法记录到19种, 样点法记录到21种, 两种调查方法平均每次记录到的鸟类种数没有显著差异, 表明两种方法对盐沼鸟类种类的发现能力相似。两种方法得到的鸟类密度之间有显著的相关性,说明两种方法在反映鸟类群落中每种鸟类的相对数量方面具有可比性。但除了仅在一种调查方法中记录到的种类, 样点法调查得到的每种鸟类密度和鸟类总密度均高于样线法的调查结果。因此, 在对鸟类种群或群落的时空特征进行比较时, 需要考虑所采用的调查方法对调查结果的影响。     

30年泰山繁殖鸟类种类变化

泰山位于山东省中部,是华北中东部地区海拔最高的山脉,地形多样,生境复杂,是鸟类重要的繁殖地和迁徙停歇地。根据1984~1988年和2013~2015年两个时期野外调查及访谈调查结果,比较了近30年泰山繁殖鸟类种类的组成变化。相比20世纪80年代记录的繁殖鸟类13目35科72种,2013~2015年的调查记录到繁殖鸟类11目34科84种,与30年前相比净增长12种繁殖鸟类,其中新增繁殖鸟类记录32种,消失鸟类记录20种。新增种类主要是林地和灌丛鸟类,多为东洋种,消失的种类主要是湿地和农田草地鸟类,多为古北种和广布种。鸟类新增和消失的原因多样,但主要是栖息地面积和质量的改变,同时私自放生也是一个重要原因。本研究结果可丰富泰山地区随时间尺度变化的鸟类本底数据,并为泰山鸟类的保护提供科学依据。     

上海崇明东滩堤内次生人工湿地鸟类冬春季生境选择的因子分析

2004年12月—2005年5月,对上海崇明东滩98海堤内200hm2次生人工湿地进行鸟类调查,在冬季统计到鸟类8目15科56种,以游、涉禽为主;在春季统计到鸟类10目19科55种,以涉禽为主。运用多元回归对鸟类种类数、数量、物种多样性、均匀性指数和科属多样性等群落特征以及调查样点内水位、水面积、植被盖度、底栖动物密度、鱼类捕捞和人类干扰等环境因子进行鸟类生境选择分析。回归模型显示冬季鸟类种类数与植被盖度呈显著正相关,鸟类数量、物种多样性、科属多样性等群落特征与水位高低、水面积比例以及鱼类捕捞强度等有关,底栖动物密度影响鸟类均匀度和数量;春季鸟类数量与鱼塘的水面积呈正相关,而种类和数量与水位呈显著负相关,物种多样性和均匀性明显受水位、水面积和植被盖度影响,鸟类科属多样性与底栖动物密度呈显著相关,捕捞状况对春季鸟类群落影响不大。     

森林-草原交错带夏季鸟类群落多样性特征

2004～2006年夏季利用样线法研究了内蒙古高原东南缘森林-草原交错带鸟类群落多样性特征及变化规律.共记录鸟类73种,隶属于13目28科56属,鸟类区系具有明显的古北界特征.鸟类群落物种数和密度年间差异不显著,α多样性随森林-草原交错带环境梯度变化而发生显著变化:在不同植被地带之间,物种数、密度、Shannon-Wiener指数和Pielou指数差异极显著、但科-属多样性差异不显著,鸟类群落α多样性各项指数表现为森林带＜交错带森林草甸区＞交错带草甸草原区＞草原带的特征与变化趋势(DG-F为交错带草甸草原区＞森林带);其中,森林草甸区是鸟类物种多样性的显著增长区,具有最高的物种数和密度,明显体现了交错区的边缘效应,草甸草原区是鸟类向草原过渡的显著变化区域、物种多样性开始显著减少.β多样性随不同植被地带逐级发生显著变化,环境差异最大的森林带-森林草甸区和草甸草原区-草原带具有最高的β多样性,物种替代速率最大;鸟类物种替代速率与环境梯度"陡度"有密切关系.鸟类优势种在各植被地带之间存在较大变化.鸟类群落的物种数、密度和物种多样性(H')与森林斑块数呈显著的正相关性,在大尺度空间上森林斑块数是影响鸟类群落多样性的最主要因素.     

上海崇明东滩堤内次生人工湿地鸟类冬春季生境选择的因子分析

2004年12月—2005年5月,对上海崇明东滩98海堤内200 hm²次生人工湿地进行鸟类调查,在冬季统计到鸟类8目15科56种,以游、涉禽为主;在春季统计到鸟类10目19科55种,以涉禽为主。运用多元回归对鸟类种类数、数量、物种多样性、均匀性指数和科属多样性等群落特征以及调查样点内水位、水面积、植被盖度、底栖动物密度、鱼类捕捞和人类干扰等环境因子进行鸟类生境选择分析。回归模型显示冬季鸟类种类数与植被盖度呈显著正相关,鸟类数量、物种多样性、科属多样性等群落特征与水位高低、水面积比例以及鱼类捕捞强度等有关,底栖动物密度影响鸟类均匀度和数量;春季鸟类数量与鱼塘的水面积呈正相关,而种类和数量与水位呈显著负相关,物种多样性和均匀性明显受水位、水面积和植被盖度影响,鸟类科属多样性与底栖动物密度呈显著相关,捕捞状况对春季鸟类群落影响不大。     

福建南日岛南部水域鱼类群落结构及多样性

为探究南日岛南部水域鱼类群落结构及多样性特征,在2009年冬季,2010年春季与夏季于南日岛南部海域展开了3个航次的渔业资源综合调查.采用Bray-Curtis聚类方法,对南日岛南部海域鱼类群落进行划分,并在此基础上分析了不同群落鱼类种类数、数量密度、生态类群和多样性特征,讨论了水团变化对鱼类群落格局划分及多样性特征的影响。结果显示:春季调查海域的鱼类可划分为北部沿岸群落和南部近海群落,这两个种群种类数分别是27和32种,密度分别为7.47×103尾/km2和24.34×10~3尾/km~2,多样度H'值分别为2.71和1.97,南部近海群落中暖水种数量密度均高于北部沿岸群落,而暖温种相反。与春季不同,夏季由西至东划分为西部沿岸群落和东部近海群落,种类数分别为55和27种,密度分别为329.24×10~3尾/km~2和106.47×103尾/km2,H'值分别为1.97和1.62,西部沿岸群落中沿岸种和近海种数量密度均高于东部近海群落。冬季调查海域鱼类可划分为北部沿岸群落和南部近海群落,种类数分别为25和32种,密度分别为9.96×10~3尾/km~2和28.85×10~3尾/km~2,H'值分别为2.45和2.33,南部近海群落暖水种与暖温种数量密度均高于北部沿岸群落。冬、春季时,海峡暖水影响的海域鱼类种类数、数量密度、多样度以及暖水种的数量密度均高于浙闽沿岸水控制的海域;夏季,西部沿岸径流影响的海域鱼类种类数、数量密度、多样度以及暖水种的数量密度均高东部海峡暖水影响的海域。可见鱼类群落分布特征与季节性变化的水团有关。     

浙江古田山自然保护区鸟类群落生态研究

对古田山地区鸟类进行的调查表明:该地区鸟类群落的主要鸟类共计48种,其中优势种有14种,占29.17％。根据鸟类生境的分布系数分析。中性分布型有(25—100％)28种,占58.33％。不同生境内鸟类群落的种类数目和群体密度存在差异,结构复杂的生境,其鸟类群落由三个分布群组成,如农田村落、农田河滩、混交林和阔叶林;结构简单的生境,如竹林、针叶林和迹地灌丛,其鸟类群落由二个分布群所组成。各种鸟类分布群在鸟类群落内的比例随栖息地结构的变化而改变。由于栖息地结构的变化同样也导致鸟类群落其他参数的变化,如Shannon-Wiener多样性指数、Simpson优势度、种间相遇机率PIE等。     

四川白坡山自然保护区冬季鸟类群落调查

2003年12月对四川白坡山自然保护区的鸟类群落的种类和数量进行了调查,实际发现鸟类151种,结合历史文献23种,保护区鸟类共有174种,隶属于12目41科。保护区有国家级重点保护鸟类14种,四川省保护鸟类2种,我国特有鸟类5种。保护区鸟类区系以东洋界成分为主。利用多样性指数分析了不同群落的鸟类多样性,结果表明:地处1300~2600 m的中山云南松及其混交林群落鸟类多样性最高,原因是该群落中生境类型丰富多样。     

四川金佛山嘉利树林的初步研究

本文对我国一个特有的植物群落——嘉利树林的立地条件、群落组成及其地理分布以及群落结构等,作了初步分析。从群落区系成分的分析,表明了该群落在种类组成上的特点及古老性,从而证实嘉利树林的古老性质。从生活型谱的分析表明,嘉利树林具有以落叶中高位芽植物为主的特点。对该群落的动态也作了初步分析。     

Breakdown of the species-area relationship in exotic but not in native forest patches

We studied the pattern of bird species richness in native and exotic forest patches in Hungary. We hypothesized that species-area relationship will depend on forest naturalness, and on the habitat specialization of bird species. Therefore, we expected strong species-area relationship in native forest patches and forest bird species, and weaker relationship in exotic forest patches containing generalist species. We censused breeding passerine bird communities three times in 13 forest patches with only native tree species, and 14 with only exotic trees in Eastern Hungary in 2003. Although most bird species (92%) of the total of 41 species occurred in both exotic and native forests, the species-area relationship was significant for forest specialist, but not for generalist species in the native forests. No relationship between bird species and area was found for either species group in the forest with exotic tree species. The comparison of native versus exotic forest patches of similar sizes revealed that only large (>100 ha) native forests harbor higher bird species richness than exotic forests for the forest specialist bird species. There is no difference between small and medium forest patches and in richness of generalist species. Thus, the species-area relationship may diminish in archipelago of exotic habitat patches and/or for habitat generalist species; this result supports the warning that the extension of exotic habitats have been significantly contributing to the decline of natural community patterns.     

Alternative pathways of liana communities in the forests of northwestern Argentina

Liana dynamics in secondary and mature forests are well known in tropical areas dominated by native tree species. Outside the tropics and in secondary forests invaded by exotic species, knowledge is scarce. In this study, we compare liana communities between secondary and mature forests dominated by native species in a subtropical montane area of Sierra de San Javier, Tucuman, Argentina. Additionally, we evaluate changes of liana communities in secondary forests with increasing densities of Ligustrum lucidum and Morus alba, two of the most invasive exotic trees of the area. We surveyed liana species richness and density in three 30-year secondary patches, four 60-year secondary patches, and four mature patches dominated by native tree species, to analyze changes in liana communities with forest age. Within each patch, we sampled 10–25 20 × 20 m quadrats. Additionally, we surveyed liana density and species richness in secondary forest patches with different densities of L. lucidum and M. alba. In native-dominated forests, liana species richness increased and showed a tendency of increasing basal area from 30-year secondary forests to mature forests. Liana density was highly variable, and most of the species were shared between native-dominated secondary and mature forests. Liana density and species richness decreased with L. lucidum density, whereas in secondary forests highly dominated by M. alba, lianas increased in density. Overall, lianas followed different pathways influenced by native forest succession and exotic tree invasions.     

香港乡土树种幼苗在次生林下生长的研究

通过苗木移植试验,测定了２１种香港乡土树种在次生林下的成活率及生长状况。结果表明,大多数种类的幼苗具有一定的耐荫性,可在林下生长;只有极少数种类表现出极耐荫或极不耐荫,导致林下先锋树种幼苗死亡率高的主要原因是荫蔽或因荫蔽而生长不良受病虫害致死。在香港次生林演替中占优势的种类通常具有生长快、稍耐荫,或生长稍慢但耐胁迫等特点。这是对香港退化土地长期适应的结果。鸟播植物在香港次生林中占有重要地位,建议加     

Bird Community Changes in Response to Single and Repeated Fires in a Lowland Tropical Rainforest of Eastern Borneo

Our current understanding of bird community responses to tropical forest fires is limited and strongly geographically biased towards South America. Here we used the circular plot method to carry out complete bird inventories in undisturbed, once burned (1998) and twice burned forests (1983 and 1998) in East Kalimantan (Indonesia). Additionally, environmental variables were measured within a 25 m radius of each plot. Three years after fire the number of birds and bird species were similar for undisturbed and burned forests, but species diversity and turnover were significantly lower in the burned forests. The bird species composition also differed significantly between undisturbed and burned forests, with a strong decline of closed forest preferring bird species accompanied by a strong increase in degraded forest preferring species in burned forests. These differences were strongly related to differences in environmental conditions such as shifts in vegetation cover and layering and differences in ground and understorey vegetation structure. We also found significant shifts in body mass distribution, foraging height and feeding guilds between the bird communities in unburned and burned forests. Surprisingly, repeated burning did not lead to increasing impoverishment of the avifauna, and both once and twice burned forests still contained most of the bird species that were also present in undisturbed forest, even though their densities were considerably lowered.     

香港次生林下植物菌根的调查

本文报道了香港６４种野生植物根系天然感染菌根菌的状况：９８．４％的植物都不同程度地感染上了菌根菌,９８．１％的根样发现受内生菌根（ＶＡＭ）的感染,其中小叶青冈（Ｑｕｅｒｃｕｓｍｙｒｓｉｎａｅｆｏｌｉａ）同时受外生菌根（ＥＣＭ）和内生菌根的感染。该研究揭示了香港次生林植物在自然条件下受菌根菌感染的普遍性,为进一步探讨华南地区菌根与退化地区植物群落演替的关系提供了重要的本底资料。     

High Bird Species Diversity in Structurally Heterogeneous Farmland in Western Kenya

Tropical ecosystems are globally important for bird diversity. In many tropical regions, land‐use intensification has caused conversion of natural forests into human‐modified habitats, such as secondary forests and heterogeneous agricultural landscapes. Despite previous research, the distribution of bird communities in these forest‐farmland mosaics is not well understood. To achieve a comprehensive understanding of bird diversity and community turnover in a human‐modified Kenyan landscape, we recorded bird communities at 20 sites covering the complete habitat gradient from forest (near natural forest, secondary forest) to farmland (subsistence farmland, sugarcane plantation) using point counts and distance sampling. Bird density and species richness were on average higher in farmland than in forest habitats. Within forest and farmland, bird density and species richness increased with vegetation structural diversity, i.e., were higher in near natural than in secondary forest and in subsistence farmland than in sugarcane plantations. Bird communities in forest and farmland habitats were very distinct and very few forest specialists occurred in farmland habitats. Moreover, insectivorous bird species declined in farmland habitats whereas carnivores and herbivores increased. Our study confirms that tropical farmlands can hardly accommodate forest specialist species. Contrary to most previous studies, our findings show that structurally rich tropical farmlands hold a surprisingly rich and distinct bird community that is threatened by conversion of subsistence farmland into sugarcane plantations. We conclude that conservation strategies in the tropics must go beyond rain forest protection and should integrate structurally heterogeneous agroecosystems into conservation plans that aim at maintaining the diverse bird communities of tropical forest‐farmland mosaics.     

Birds,Cattle, and Bracken Ferns: Bird Community Responses to a Neotropical Landscape Shaped by Cattle Grazing Activities

Large areas of tropical moist forests have been converted to cattle pastures, generating complex landscapes where different habitats are represented by small patches with an uneven spatial distribution. Here, we describe how bird communities respond to the different elements present in a livestock landscape that was originally dominated by tropical moist forest. We surveyed six habitats: open pastures, pastures with shrubs, early‐ and middle‐secondary forests, mature forest, and pastures invaded by bracken ferns (Pteridium aquilinum). Bird diversity was high in secondary and mature forests, and low in fern‐invaded sites and open pastures. Fern‐dominated sites had the lowest bird species richness, and trophic guild diversity of all habitats. Habitat structure affected both bird species richness and densities in similar ways. Tree species richness was the habitat attribute that had a bigger positive effect on bird species richness. Bird community structure varied among sampled habitats, separating habitats in two major groups (forests and pastures). Our data indicate that bracken fern‐invaded pastures were the worst habitat condition for avian communities. To increase bird diversity, we recommend to eliminate or manage bracken fern and to increase shrub and tree cover in open pastures to provide food resources and shelter for birds. Finally, we encourage the maintenance of secondary and mature forest remnants as a strategy to conserve resident birds within a landscape dominated by livestock activities.     

Seasonality of a forest bird community in Hong Kong, South China

We studied the composition of a secondary forest bird community in Hong Kong (22^°N) between December 1992 and June 1995, using the variable point count method. The visual detectability of each bird species had a significant positive relationship with body length. A total of 71 bird species was recorded but three resident habitat-generalists, the Great Tit Parus major, Light-vented Bulbul Pycnonotus sinensis and Japanese White-eye Zosterops japonicus, accounted for 65% of the mean total bird density of 38 per ha. The number of species seen was highest between December and April and lowest from July to September, but the total bird density was highest between December and June and lowest from August to September. The main breeding season was from March to August. Insectivores and insectivore-frugivores accounted for 80% of the species and 98% of the total bird density. The percentages of migrant species and individuals are similar to those reported at equivalent latitudes in North America. Bird community diversity and composition differed considerably from that of larger, older forest areas in South China, presumably as a result of differences in forest age, area and isolation.     

Succession of bird communities in young temperate rainforests following thinning

We repeated bird and vegetation surveys in 1991–1992 and 2005–2006 among young managed stands and old-growth forests in southeast Alaska to evaluate whether pre-commercial thinning of managed stands influenced the bird community. We compared decadal changes in bird densities and forest vegetation among 3 stand types: managed stands originating from clearcuts 35 years ago that were left untreated (unthinned), managed stands thinned at uniform spacing (thinned), and old growth with no prior timber harvest. We did not detect differences in decadal trends in avian densities between thinned and unthinned stands for 15 of 16 common bird species using a repeated-measures design. Thinning did not result in greater recruitment of overstory-nesting species as predicted. This was likely because of 1) similar increases in tree heights ( = 9–10 m) and canopy cover ( = 29–43%) between unthinned and thinned stands across decades and 2) the relatively young successional stage of these stands, which had only begun to recruit medium and large size conifers (dbh ≥ 36 cm). Decadal trends in densities of most (88%) understory-nesting bird species did not differ between thinned and unthinned stands. Shrub cover decreased by 22% and 31% across decades in thinned and unthinned stands, respectively. Bird community composition in managed stands reflected the general decadal changes in forest vegetation with a shift in dominance from understory species in the early 1990s (80–85% of total bird density) to an equal abundance of understory (45–54%) and overstory species in the mid-2000s. The latter was more similar to old-growth stands, which were dominated by overstory species (67–71%). Overstory-nesting birds in old growth increased in density by 49% across decades. Densities of cavity-nesting species remained unchanged in managed stands and less than densities in old growth across decades, possibly because of a lack of large trees and snags for nest sites. Overall, thinning of clearcut stands, the primary silvicultural system in the region, had few measurable benefits to birds nearly 20 years after treatment. Monitoring over the 70–100-year harvest rotation may be necessary to fully test whether thinning accelerates succession of bird communities in clearcut stands. However, partial harvests that retain large trees and snags should also be explored as alternatives to better maintain late-succession avifauna throughout the harvest rotation in southeast Alaska. © 2012 The Wildlife Society.     

Rapid colonization of a Hawaiian restoration forest by a diverse avian community

Deforestation of tropical forests has led to widespread loss and extirpation of forest bird species around the world, including the Hawaiian Islands which have experienced a dramatic loss of forests over the last 200–800 years. Given the important role birds play in forest ecosystem functions via seed dispersal and pollination, a bird community's response to forest restoration is an important measure of the success of such conservation actions. We evaluated the bird response to reforestation at an important bird sanctuary, Hakalau Forest National Wildlife Refuge, Hawai′i Island, using 26 years of bird count data. We show that most species from within the diverse avian community increased significantly, but species colonized the restoration forest at different rates. Distance from intact forest and time since restoration were both important predictors of colonization rate, interacting such that for most species it took more time to colonize areas farther from the intact forest. In addition, both forest cover and understory diversity helped to explain bird densities, but the effect varied among species, suggesting that different habitat requirements may help drive variation in colonization rates. This article provides the first detailed evaluation of how a diverse community of birds has responded to one of the largest, ongoing reforestation projects in Hawai′i.