Seasonal Abundance and Species Richness of Birds in Common Reed Habitats in Lake Erie

Abstract: Common reed (Phragmites australis) forms dense stands with deep layers of residual organic matter that negatively affects plant diversity and possibly habitat use by wetland birds. We sought to determine whether seasonal relative abundance and species richness of birds varied among 3 habitat types in Great Lakes coastal wetland complexes recently invaded by common reed. We used fixed-distance point counts to determine species relative abundances and species richness in edge and interior locales within common reed, cattail (Typha spp.), and meadow marsh habitats of various sizes during 2 summers (2001 and 2002) and 1 autumn (2001) at Long Point, Lake Erie, Ontario, Canada. We found that total relative abundance and species richness of birds were greater in common reed habitat compared to cattail or meadow marsh habitats. However, we also found that relative abundance of marsh-nesting birds was greater in meadow marsh habitat than in cattail and common reed during summer. Lastly, we found that, irrespective of habitat type, habitat edges had higher total relative abundance and species richness of birds than did habitat interiors. Our results show that common reed provides suitable habitat for a diversity of landbirds during summer and autumn but only limited habitat for many marsh-nesting birds during summer. Based on these results, we recommend restoration of meadow marsh habitat through reduction of common reed in Great Lakes wetlands where providing habitat for breeding marsh-nesting birds is an objective. Managers also might consider reducing the size of nonnative common reed stands to increase edge effect and use by birds, possibly including wetland birds.     

Abundance and Movement of Understory Birds in a Maulino Forest Fragmented by Pine Plantations

Understory birds are especially vulnerable to habitat fragmentation because of the reduction in habitat quality and bird movement. We study the separate effects of understory, overstory and landscape on four understory birds (tapaculos), in Central Chile, comprising a landscape mosaic of pine (Pinus radiata D. Don) plantations and native Maulino forest fragments. We also determined whether habitats with poor understory could be barrier to tapaculos movements. Abundance was measured using stationary playbacks and habitat barrier through playbacks. Understory structure was the main factor that predicted tapaculos presence and abundance. Two species, the Andean Tapaculo (Scytalopus magellanicus fuscus Gmelin) and the Ochre-flanked Tapaculo (Eugralla paradoxa Kittlitz), were positively associated with dead pine branches and negatively to forest fragment size. Tapaculos were less abundant in mature native forest, but appeared willing to cross between different habitat types. However, the Chestnut-throated Huet-huet (Pteroptochos castaneus Philippi and Landbeck), did not move from forest fragments to pine with poor understory. Overall, tapaculos species varied in their response to fragmentation depending on their habitat selection and movement capacities.     

Seed Dispersal by Bats and Birds in Forest and Disturbed Habitats of Chiapas,Mexico1

We examined seed dispersal by bats and birds in four habitats of the Selva Lacandona tropical rain forest region, Chiapas, Mexico. The four habitats represented a disturbance gradient: active cornfield, ten-year-old abandoned cornfield, cacao plantation, and forest. Using seed traps examined before sunrise (0400 h) and before sunset (1800 h), we compared volant vertebrate seed dispersal, assuming that seeds found at the end of the night were dispersed by bats and those found at the end of the day were dispersed by birds. We did not find seeds from other frugivores such as monkeys or opossums. In all habitats bats dispersed more seeds than birds. In most months bats also dispersed more seeds than birds, except in December when no seeds were found in the traps. Bats also consistently dispersed more species of seeds than birds, although a x2 comparison showed differences not to be significant. Fifty percent of the species represented in the dispersed seeds in all habitats were pioneer species. Cecropia seeds represented a high percentage (up to 87% of those dispersed by bats and up to 83% by birds) of dispersed seeds that fell in our traps. The influence of bats and birds on secondary successional processes is likely to be fundamental for the establishment of vegetation. Since bats dispersed more seeds than birds (primarily to disturbed areas and consisting primarily of pioneer species), they are likely to play an important role in successional and restoration processes among habitats as structurally and vegetationally different as cornfields, old fields, cacao plantations, and forest.     

北京市平原区受胁鸟类栖息地识别和评价

在北京分布的受胁鸟类主要分布在平原区,而平原区为城市发展的主要区域,因此,在城市管理中融入受胁鸟类保护的内容十分必要。以北京市平原区分布的24种受胁鸟类为研究对象,以鸟类对栖息地的需求为分类依据,结合国家土地利用分类标准,采用人工目视解译法,在北京市平原区的高清卫星影像图上识别出5类一级鸟类栖息地和17类二级鸟类栖息地,得到北京市平原区鸟类栖息地分布图。使用24种受胁鸟类的空间分布模型掩膜鸟类栖息地分布,得到24种受胁鸟类的预测空间分布,叠加之后获得受胁鸟类丰富度分布格局,结果显示,水域是受胁鸟类丰富度最高的栖息地。将受胁鸟类丰富度分布格局与北京市国家级和市级自然保护区分布叠加进行空缺分析,结果显示：1）北京市的自然保护区多分布在山区,不能有效保护受胁鸟类;2）受胁鸟类的保护与平原区的城市建设、绿地管理关系密切。采用分区统计方法,计算各类栖息地中分布的平均鸟类种类数,作为栖息地保护行动优先级指标,得出湖泊、水库、坑塘、滩地、沼泽地等湿地区域是具有最高保护优先级的栖息地类型,在保护实践资源充足的情况下,应对各类栖息地开展综合保护。该研究首次为北京城市区域受胁鸟类保护提出空间参考和管理建议。     

Effect of Leaf Type and Pesticide Exposure on Abundance of Bacterial Taxa in Mosquito Larval Habitats

Lentic freshwater systems including those inhabited by aquatic stages of mosquitoes derive most of their carbon inputs from terrestrial organic matter mainly leaf litter. The leaf litter is colonized by microbial communities that provide the resource base for mosquito larvae. While the microbial biomass associated with different leaf species in container aquatic habitats is well documented, the taxonomic composition of these microbes and their response to common environmental stressors is poorly understood. We used indoor aquatic microcosms to determine the abundances of major taxonomic groups of bacteria in leaf litters from seven plant species and their responses to low concentrations of four pesticides with different modes of action on the target organisms; permethrin, malathion, atrazine and glyphosate. We tested the hypotheses that leaf species support different quantities of major taxonomic groups of bacteria and that exposure to pesticides at environmentally relevant concentrations alters bacterial abundance and community structure in mosquito larval habitats. We found support for both hypotheses suggesting that leaf litter identity and chemical contamination may alter the quality and quantity of mosquito food base (microbial communities) in larval habitats. The effect of pesticides on microbial communities varied significantly among leaf types, suggesting that the impact of pesticides on natural microbial communities may be highly complex and difficult to predict. Collectively, these findings demonstrate the potential for detritus composition within mosquito larval habitats and exposure to pesticides to influence the quality of mosquito larval habitats.     

The Relationship between Local Abundance and Distribution of Rain Forest Trees across Environmental Gradients in India

We tested whether local abundance of rain forest trees in the medium elevation wet forests of the southern Western Ghats (WG) was related to environmental tolerance, life form, and geographical range. We selected trees in medium elevation wet forests (750–1700 m asl) of the southern WG, using two data bases: a small plot (30 × 30 m) data base of 288 species of trees (≥ 3 cm dbh) in 33 plots totaling 2.97 ha, and a data base of 135 species of tree (≥ 10 cm dbh) in larger plots of 1 ha each, totaling 4.84 ha. The species density per hectare and number of records in the plot network was used in a factor analysis to give a measure of the local abundance of each species. The altitude and seasonality ranges of these species in the WG was assessed from independent data bases and used to generate an environmental tolerance score. Results indicated that as a species became locally more abundant, it occurred across a wider range of environmental gradients, but regional distribution was not related to geographical distribution. Understory species tended to be rarer with smaller range sizes and lower environmental tolerances than overstory species. Climate change is predicted to have drastic effects on restricted range species with limited environmental tolerances.     

Effects of Habitat Structure and Adjacent Habitats on Birds in Tropical Rainforest Fragments and Shaded Plantations in the Western Ghats, India

As large nature reserves occupy only a fraction of the earth’s land surface, conservation biologists are critically examining the role of private lands, habitat fragments, and plantations for conservation. This study in a biodiversity hotspot and endemic bird area, the Western Ghats mountains of India, examined the effects of habitat structure, floristics, and adjacent habitats on bird communities in shade-coffee and cardamom plantations and tropical rainforest fragments. Habitat and birds were sampled in 13 sites: six fragments (three relatively isolated and three with canopy connectivity with adjoining shade-coffee plantations and forests), six plantations differing in canopy tree species composition (five coffee and one cardamom), and one undisturbed primary rainforest control site in the Anamalai hills. Around 3300 detections of 6000 individual birds belonging to 106 species were obtained. The coffee plantations were poorer than rainforest in rainforest bird species, particularly endemic species, but the rustic cardamom plantation with diverse, native rainforest shade trees, had bird species richness and abundance comparable to primary rainforest. Plantations and fragments that adjoined habitats providing greater tree canopy connectivity supported more rainforest and fewer open-forest bird species and individuals than sites that lacked such connectivity. These effects were mediated by strong positive effects of vegetation structure, particularly woody plant variables, cane, and bamboo, on bird community structure. Bird community composition was however positively correlated only to floristic (tree species) composition of sites. The maintenance or restoration of habitat structure and (shade) tree species composition in shade-coffee and cardamom plantations and rainforest fragments can aid in rainforest bird conservation in the regional landscape.     

Presence and Abundance of Birds in an Atlantic Forest Reserve and Adjacent Plantation of Shade-Grown Yerba Mate,in Paraguay

In the Atlantic forest region, there is a need to develop economic activities that can be carried out in buffer zones around parks, with minimal impact on forest bird species. One such possibility is the farming of yerba mate, Ilex paraguariensis, under native trees. We compared bird speciesȁ9 presence and abundance between a forest reserve and an adjacent plantation of shade-grown yerba mate, to determine which species might use such plantations. Of the 145 species that were regularly recorded in the forest, 66%, including five globally threatened species, were also regularly recorded in the plantation. Most canopy species and tree trunk insectivores showed similar abundance in both habitats, but forest floor and understory species were absent from the plantation. Within the plantation, higher tree density did not lead to a greater abundance of forest birds. Yerba mate grown under native trees could be used to rehabilitate cleared land and allow recolonization by some Atlantic forest bird species.     

Differential Movement Patterns of Juvenile Tengmalms Owls (Aegolius funereus) during the Post-Fledging Dependence Period in Two Years with Contrasting Prey Abundance

Fledgling behaviour and movement patterns throughout the post-fledging dependence period (PFDP), especially in relation to changing environmental conditions, have been rarely studied, despite the fact that this period is recognized as of crucial significance in terms of high mortality of juveniles. The PFDP can extend over quite a protracted period, particularly in birds of prey, and a knowledge of the movement patterns of individuals is fundamental for understanding mechanisms underlying survival, habitat use and dispersion. We radiotracked 39 fledglings of the Tengmalm’s owl (Aegolius funereus) in two years with different availability of prey: 2010 (n = 29) and 2011 (n = 10) and obtained 1455 daily locations. Fledglings reached independence on average in 45 days after fledging in 2010 (n = 22) and 57 days in 2011 (n = 6). Within years, the most important measures influencing the distance moved from the nest box were age of fledglings and number of surviving siblings present. Individual home range size and duration of PFDP in particular were dependent on maximal number of siblings seen outside the nest box. In the season with low prey availability fledglings were observed at greater distances from the nest box than in the year with higher prey availability (mean distance: 350 m in 2010 and 650 m in 2011) and occupied larger home ranges (mean: 30.3 ha in 2010 and 57.7 ha in 2011). The main factor causing these differences between years was probably the different availability of prey in these two years, affecting breeding success and post-fledging survivorship of the Tengmalm’s owls.     

繁殖期贵阳本地鸟类贸易现状

动物贸易是生物多样性丧失的重要原因,在物种的繁殖期进行捕捉和贸易对种群更是不利。为分析和评价贵阳本地鸟类在繁殖期间的生存现状和保护需求,于2014年3—6月调查了贵阳市油榨街花鸟市场上被交易的鸟类。共记录到114种当地鸟类,种数超过贵阳当地鸟类总数的50%,其中7种为保护物种。用于"斗鸟"的灰喉鸦雀Paradoxornis alphonsianus被交易的数量最高,画眉Garrulax canornus、红嘴相思鸟Leiothrix lutea、暗绿绣眼鸟Zosterops japonicas、红尾水鸲Rhyacornis fuliginosus和黄喉鹀Emberiza elegans等数量次之。接近80%的陆栖或半陆栖的鸟类及其雏鸟在繁殖期间都面临着很高的被捕捉风险。除了开展人工繁育,还建议开展野生鸟类的性别识别和性比研究,以减少野生雌鸟的损失和评价鸟类物种保护的优先性,同时加大宣传,将笼养鸟类者发展为支持鸟类研究和保护的重要力量。     

Effect of Forest Fragmentation on Tick Infestations of Birds and Tick Infection Rates by Rickettsia in the Atlantic Forest of Brazil

Habitat loss and modifications affect biodiversity, potentially contributing to outbreaks of infectious diseases. We evaluated if the patch sizeinfragmented areas of Atlantic Forest in southeastern Brazil influences the diversity of forest birds and consequently the prevalence of ticks on birds and the rickettsial infection of these ticks. During 2 years, we collected ticks from birds in 12 sites: four small forest patches (80–140 ha), four large ones (480–1,850 ha), and four forest control areas within the much larger Morro do Diabo State Park (~36,000 ha). A total of 1,725 birds were captured (81 species, 24 families), from which 223 birds were infested by 2,339 ticks of the genus Amblyomma, mostly by the species A. nodosum. Bird diversity and richness were higher in larger than smaller forest fragments. The prevalence of ticks on birds was inversely correlated with bird diversity and richness. Among 174 A. nodosum tested for rickettsial infection by polymerase chain reaction, 51 were found to be infected by Rickettsia bellii or Rickettsia parkeri. However, tick infection rates by Rickettsia spp. were not statistically different between forest patch sizes. The higher prevalence of ticks on birds in degraded patches might be caused by a dominance of a few generalist bird species in small patches, allowing an easier transmission of parasites among individuals. It could also be related to more favorable microclimatic conditions for the free-living stages of A. nodosum in smaller forest fragments.The higher burden of ticks on birds in smaller forest fragments is an important secondary effect of habitat fragmentation, possibly increasing the likelihood of Rickettsia contagion.     

The Post-Fledging Mortality of the Blackbird in Great Britain

Some 3,000 pairs of Herring Gulls are now known to be nesting on buildings, mainly in coastal towns they are increasing most rapidly in eastern Britain, where recruitment is taking place from natural colonies. A smaller number of Lesser Black-backed Gulls has occupied rooftops in the Bristol Channel region.     

The Age Composition and Postmetamorphic Growth Characteristics of the Moor Frog (Rana arvalis) from Habitats with a Short Activity Season

Biology Bulletin - The between-population and sexual differences in demographic and postmetamorphic growth characteristics were studied in Rana arvalis from several habitats of Khanty-Mansiiskii...     

The Relative Impact of Harvest and Fire upon Landscape-Level Dynamics of Older Forests: Lessons from the Northwest Forest Plan

Interest in preserving older forests at the landscape level has increased in many regions, including the Pacific Northwest of the United States. The Northwest Forest Plan (NWFP) of 1994 initiated a significant reduction in the harvesting of older forests on federal land. We used historical satellite imagery to assess the effect of this reduction in relation to: past harvest rates, management of non-federal forests, and the growing role of fire. Harvest rates in non-federal large-diameter forests (LDF) either decreased or remained stable at relatively high rates following the NWFP, meaning that harvest reductions on federal forests, which cover half of the region, resulted in a significant regional drop in the loss of LDF to harvest. However, increased losses of LDF to fire outweighed reductions in LDF harvest across large areas of the region. Elevated fire levels in the western United States have been correlated to changing climatic conditions, and if recent fire patterns persist, preservation of older forests in dry ecosystems will depend upon practical and coordinated fire management across the landscape. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Author Contributions: The study was conceived and designed by S.P.H., W.B.C., T.A.S, and M. M. The paper was written primarily by S.P.H, with editorial help by T.A.S. and W.B.C. The research itself, including mapping and analysis, was performed by S.P.H., D.P., M.G.W., and M.L. M.M. contributed additional methodologies related to the creation and validations of maps of historical older forests.     

Male and Female Activity Patterns in Microcebus murinus During the Dry Season at Kirindy Forest, Western Madagascar

I investigated sexual differences in activity levels, and their adaptive significance in gray mouse lemurs, Microcebus murinus, during the dry season. I studied them between April and September, 1999, at Kirindy Forest, a dry deciduous forest in western Madagascar. Six males and 6 females were radiocollared and followed using focal individual sampling. The males remained active throughout the dry season, whereas the females hibernated for up to 3 mo. Males exhibited a gradual decrease in activity from May to June and some of them remained inactive for periods of a few days to 1 wk. Males were more active in July. Though there were changes in the duration of time spent sleeping, there was no significant change in male body mass throughout the period. Males appear to prefer to rest in nests that are close to or coincident with those preferred by females, and multiple males may simultaneously share nests with multiple hibernating females. Males occupying nests that are close to or coincident with nests preferred by females tend to switch nests less frequently than others do. Researchers have suggested that high levels of activity prepare males for the mating season, which occurs at the end of the dry season. Presumably, by maintaining an active lifestyle throughout the dry season, certain males may position themselves to monopolize the best tree holes during the mating season. The reproductive advantages gained by this behavior may overshadow the costs of remaining active during the dry season when resources are scarce, temperatures are low, and predator pressure is high. Measurements on captured males confirm a weak (nonsignificant) positive correlation between body mass and activity levels. There is no indication that the heavier, more active males were better able to monopolize the best tree holes.     

Effects of Management Intensity and Season on Arboreal Ant Diversity and Abundance in Coffee Agroecosystems

Agricultural intensification decreases arthropod predator diversity, abundance and population stability, and may affect interactions between top predators and their arthropod prey – ultimately affecting ecosystem services. Coffee management intensification (reduction or removal of shade trees) reduces diversity of arthropod predators (ground-foraging ants). Because ants provide ecosystem services by controlling pests, influences of intensification on arboreal, coffee-foraging ant diversity and abundance are important. We here address how coffee intensification affects: (1) coffee-foraging ant diversity and abundance and (2) seasonal fluctuations in ant abundance. In each of four coffee sites of varying management intensity in Chiapas, Mexico, we sampled vegetation and using two methods, sampled ant diversity and abundance over two years. Sites significantly differed in vegetation and management intensity. Coffee-foraging ant diversity generally decreased with increasing management intensity (16–26% fewer species observed in the most intensively-managed site). Ant abundance was higher in the wet season. Management intensity, however, did not influence ant abundance or seasonal fluctuations in abundance. Our results highlight the importance of diverse agricultural systems in maintaining arthropod predator diversity, and point to one model system in which we may effectively test how diversity per se affects ecosystem services.     

Birds in Anthropogenic Landscapes: The Responses of Ecological Groups to Forest Loss in the Brazilian Atlantic Forest

Habitat loss is the dominant threat to biodiversity and ecosystem functioning in terrestrial environments. In this study, we used an a priori classification of bird species based on their dependence on native forest habitats (forest-specialist and habitat generalists) and specific food resources (frugivores and insectivores) to evaluate their responses to forest cover reduction in landscapes in the Brazilian Atlantic Forest. From the patch-landscapes approach, we delimited 40 forest sites, and quantified the percentage of native forest within a 2 km radius around the center of each site (from 6 - 85%). At each site, we sampled birds using the point-count method. We used a null model, a generalized linear model and a four-parameter logistic model to evaluate the relationship between richness and abundance of the bird groups and the native forest amount. A piecewise model was then used to determine the threshold value for bird groups that showed nonlinear responses. The richness and abundance of the bird community as a whole were not affected by changes in forest cover in this region. However, a decrease in forest cover had a negative effect on diversity of forest-specialist, frugivorous and insectivorous birds, and a positive effect on generalist birds. The species richness and abundance of all ecological groups were nonlinearly related to forest reduction and showed similar threshold values, i.e., there were abrupt changes in individuals and species numbers when forest amount was less than approximately 50%. Forest sites within landscapes with forest cover that was less than 50% contained a different bird species composition than more extensively forested sites and had fewer forest-specialist species and higher beta-diversity. Our study demonstrated the pervasive effect of forest reduction on bird communities in one of the most important hotspots for bird conservation and shows that many vulnerable species require extensive forest cover to persist.     

The Assemblage of Birds Foraging in Native West Indian Pine (Pinus occidentalis) Forests of the Dominican Republic during the Nonbreeding Season1

We studied avian resource use in a native West Indian pine (Pinus occidentalis) forest in the Cordillera Central of the Dominican Republic during the nonbreeding season. The forest is characterized by a fairly open pine canopy and a dense mixed-broadleaf and pine understory. We used a principal components analysis of 23 foraging characters for 23 bird species, including foraging height, the proportional use of 5 different foraging methods, 3 horizontal positions and foliage densities, and 11 foraging substrates. Five principal components accounted for 74 percent of the total variance of the assemblage variables and resulted in the delineation of at least 5 foraging guilds. 78 percent of bird species had mean foraging heights of 5.0–10.0 m, corresponding to the region of overlap of pine and broadleaf vegetation. As a result, the diversity of foraging substrates and maneuvers used by birds, rather than foraging height, appears to be the primary means by which birds that exploit this habitat separate ecologically. Migrant wood warblers (Parulinae) are probably able to integrate into the community because of little diet overlap between residents and migrants, and the fairly specialized nature of their largely insectivorous foraging habits. Avian foraging in this habitat may reflect the effects of frequent disturbance such as hurricanes.     

The Influence of Habitat,Season, and Detectability on Abundance Estimates across an Amazonian Parrot Assemblage

The Amazon basin holds very high parrot species richness but almost nothing is known of parrot population densities in the region or how these vary between species, habitats, sites, and seasons. Such data are becoming important as humans impact on increasing areas of the region. Seventeen parrot species were surveyed using a line transect distance sampling method over 3 yr in floodplain and terra firme forests at two sites in the Tambopata region of southeast Peru. Density estimates for most species were in the range of 3.3–7.8/km², with Brotogeris cyanoptera and Amazona farinosa reaching densities of 22 and 23/km² in floodplain forest during the dry season. Parrot densities were higher in floodplain forest than in terra firme forest at both sites. The parrot communities of terra firme forests were similar across sites and seasons, but those in floodplain forests differed widely across sites and across seasons. Upper canopy birds are notoriously difficult to survey. We introduce a procedure to correct for the likely violation of the assumption that all birds on the transect line are detected (distance sampling assumption g(0) = 1). We correct g(0) based on calling rates of birds using a cue‐counting technique. Multipliers for g(0) differ across species and site, but not season. This method yielded density estimates on average 22 percent higher (6–40% higher in individual species) than those from the standard method.