Bird Guilds Research Articles

Bird guild loss and its determinants on subtropical land-bridge islands, China

BackgroundThe guild concept is useful for understanding the community structure in a land-bridge island system, but most fragmentation studies have focused only on the importance of island area and isolation, other island attributes such as perimeter-area ratio (PAR) were overlooked or understudied.MethodsWe have adopted a guild approach to investigate the impacts of island attributes on bird guild richness on a set of 41 recently isolated land-bridge islands in the Thousand Island Lake (TIL), China.ResultsWe found insectivores had the largest number of species (34 species), followed by understory foraging guilds (28 species), omnivores (27 species) and canopy guilds (25 species). Furthermore, our data showed that migrants and residents responded equally to island area, insectivores and understory guilds were sensitive to island area but omnivores and canopy guilds were not very sensitive. Most guild richness was determined by island area, except for omnivores and canopy guilds.ConclusionsAlthough PAR or habitat diversity found to be important for bird species richness, our results highlight the importance of island area in maintaining bird diversity in fragmented island systems.

Bats are Not Birds – Different Responses to Human Land‐use on a Tropical Mountain

AbstractLand‐use intensification has consequences for biodiversity and ecosystem functioning, with various taxonomic groups differing widely in their sensitivity. As land‐use intensification alters habitat structure and resource availability, both factors may contribute to explaining differences in animal species diversity. Within the local animal assemblages the flying vertebrates, bats and birds, provide important and partly complementary ecosystem functions. We tested how bats and birds respond to land‐use intensification and compared abundance, species richness, and community composition across a land‐use gradient including forest, traditional agroforests (home garden), coffee plantations and grasslands on Mount Kilimanjaro, Tanzania. Furthermore, we asked how sensitive different habitat and feeding guilds of bats and birds react to land‐use intensification and the associated alterations in vegetation structure and food resource availability. In contrast to our expectations, land‐use intensification had no negative effect on species richness and abundance of all birds and bats. However, some habitat and feeding guilds, in particular forest specialist and frugivorous birds, were highly sensitive to land‐use intensification. Although the habitat guilds of both, birds and bats, depended on a certain degree of vegetation structure, total bat and bird abundance was mediated primarily by the availability of the respective food resources. Even though the highly structured southern slopes of Mount Kilimanjaro are able to maintain diverse bat and bird assemblages, the sensitivity of avian forest specialists against land‐use intensification and the dependence of the bat and bird habitat guilds on a certain vegetation structure demonstrate that conservation plans should place special emphasis on these guilds.

First Nesting Records in Southwestern Louisiana for American Oystercatchers (Haematopus palliatus) and Reddish Egrets (Egretta rufescens), with Implications for Dredge Spoil Island Restoration

American Oystercatchers (Haematopus palliatus) and Reddish Egrets (Egretta rufescens) are coastal species of conservation concern known to nest along most of the Gulf of Mexico’s coastline. However, there is a distributional gap in breeding records for both species between southeastern Louisiana and eastern Texas. Herein, we report on the first breeding records for each species from southwestern Louisiana at Rabbit Island (Cameron Parish, Louisiana), a small, marsh island in Calcasieu Lake. Suitable nesting habitat for American Oystercatchers (1 nesting pair) was present on the island via shell rake and for Reddish Egrets (6–12 pairs, min) in clumps of Juncus roemerianus; this is the first report of Reddish Egrets utilizing this plant species for nesting. A large scale island restoration project is slated for Rabbit Island and therefore, we provide restoration recommendations for conservation planners to improve habitat suitability for multiple bird guilds at this and other potential dredge spoil island projects.

Ecological opportunity leads to the emergence of an alternative behavioural phenotype in a tropical bird.

Loss of a dominant competitor can open ecological opportunities. Ecological opportunities are considered prerequisites for adaptive radiations. Nonetheless, initiation of diversification in response to ecological opportunity is seldom observed, so we know little about the stages by which behavioural variation either increases or coalesces into distinct phenotypes. Here, a natural experiment showed that in a tropical island's guild of army ant-following birds, a new behavioural phenotype emerged in subordinate spotted antbirds (Hylophylax naevioides) after the socially dominant ocellated antbird (Phaenostictus mcleannani) died out. Individuals with this behavioural phenotype are less territorial; instead, they roam in search of ant swarms where they feed in locations from which dominant competitors formerly excluded them. Roaming individuals fledge more young than territorial individuals. We conclude that ecological opportunity arising from species loss may enhance the success of alternative behavioural phenotypes and can favour further intraspecific diversification in life-history traits in surviving species.

Nectar and pollen of the invasive century plant Agave americana as a food resource for endemic birds

Capsule Flowers of an invasive plant species are more visited by native birds than flowers of ornithophilous endemic plants.Aims To describe the bird guild and its behaviour visiting the century plant Agave americana in an insular environment and to determine which factors are affecting visitation rates.Methods We noted number and species of birds visiting inflorescences on Tenerife, Canary Islands. We used multimodel inference of generalized linear models to analyse the factors affecting the number of visits and the visitor species richness.Results Eighty-one per cent of inflorescences were visited by eight native bird species. All species fed on nectar and only the Atlantic Canary fed also on pollen. Foraging behaviour varied among species. Visitation rate increased with density and diversity of birds and flower characteristics and decreased through the day. The number of species visiting the inflorescences increased with diversity and density of birds in the surroundings and decreased through the day.Conclusion The native bird community uses the invasive century plant as a feeding resource at a higher rate than it uses endemic ornithophilous plants. This could have negative effects for the pollination of endemic plants, but positive effects for birds.

Determination of foraging thresholds and effects of application on energetic carrying capacity for waterfowl.

Energetic carrying capacity of habitats for wildlife is a fundamental concept used to better understand population ecology and prioritize conservation efforts. However, carrying capacity can be difficult to estimate accurately and simplified models often depend on many assumptions and few estimated parameters. We demonstrate the complex nature of parameterizing energetic carrying capacity models and use an experimental approach to describe a necessary parameter, a foraging threshold (i.e., density of food at which animals no longer can efficiently forage and acquire energy), for a guild of migratory birds. We created foraging patches with different fixed prey densities and monitored the numerical and behavioral responses of waterfowl (Anatidae) and depletion of foods during winter. Dabbling ducks (Anatini) fed extensively in plots and all initial densities of supplemented seed were rapidly reduced to 10 kg/ha and other natural seeds and tubers combined to 170 kg/ha, despite different starting densities. However, ducks did not abandon or stop foraging in wetlands when seed reduction ceased approximately two weeks into the winter-long experiment nor did they consistently distribute according to ideal-free predictions during this period. Dabbling duck use of experimental plots was not related to initial seed density, and residual seed and tuber densities varied among plant taxa and wetlands but not plots. Herein, we reached several conclusions: 1) foraging effort and numerical responses of dabbling ducks in winter were likely influenced by factors other than total food densities (e.g., predation risk, opportunity costs, forager condition), 2) foraging thresholds may vary among foraging locations, and 3) the numerical response of dabbling ducks may be an inconsistent predictor of habitat quality relative to seed and tuber density. We describe implications on habitat conservation objectives of using different foraging thresholds in energetic carrying capacity models and suggest scientists reevaluate assumptions of these models used to guide habitat conservation.

The North American approach to waterfowl management: synergy of hunting and habitat conservation

Hunters have been central to waterfowl management in North America over the past century. Numerous partnerships among government agencies, non-government organizations and private individuals form the core of conservation endeavours for migratory ducks, geese and swans and their diverse habitats. As a consequence of these efforts and the resilience of waterfowl populations, these species have fared better than most guilds of migratory birds. Threats to remaining habitats and the waning connections of people to wild things and wild places comprise the most serious challenges to sustaining this system.

Frugivorous Bird Guild Seasonal Patterns in Semiarid Chaco Forests are Linked to Habitat Seasonality but Reveal Phylogenetic Signature

Fil: Marco, Diana Elizabeth. Universidad Catolica de Cordoba. Facultad de Ciencias Agropecuarias; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina

千岛湖陆桥岛屿鸟类集团对栖息地片段化的敏感性及其季节变化

PDF HTML阅读 XML下载 导出引用 引用提醒 千岛湖陆桥岛屿鸟类集团对栖息地片段化的敏感性及其季节变化 DOI: 10.5846/stxb201406261319 作者: 作者单位: 浙江大学生命科学学院,广东省昆虫研究所 华南濒危动物研究所,浙江大学生命科学学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目(31170397,31210103908) Seasonal changes in sensitivity of bird guilds to habitat fragmentation on land- bridge islands in the Thousand Island Lake, China Author: Affiliation: College of Life Sciences, Zhejiang University,,College of Life Sciences, Zhejiang University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为探究千岛湖陆桥岛屿不同鸟类集团对栖息地片段化敏感性的差异和季节变化,于2009年4月-2012年1月鸟类繁殖季(4、5、6月)和冬季(11、12、1月)对千岛湖41个陆桥岛屿鸟类集团进行了研究。结果表明,冬季杂食鸟对片段化敏感性高于食虫鸟,繁殖季时二者无显著差异,繁殖季和冬季时下层鸟对片段化敏感性均高于林冠鸟,冬季留鸟对片段化敏感性高于候鸟,繁殖季则无显著差异。杂食鸟和留鸟对片段化敏感性存在季节差异,而食虫鸟、林冠鸟、下层鸟和候鸟对片段化敏感性均无季节差异。不同鸟类集团对栖息地片段化敏感性的差异和季节变化规律,有助于人们在栖息地管理和保护区设计时采取更有针对性的鸟类保护措施。 Abstract:Habitat loss and fragmentation seriously threaten global species diversity. Understanding the impact on species and communities is a core issue for ecology and conservation biology. A guild acts as a functional unit within a community. Bird guild research can help to analyze relationships among different species and evaluate their responses to habitat fragmentation. Much research has focused on bird guilds in terrestrial fragments, while other fragmented systems, such as land-bridge islands, draw relatively less attention. Because different systems tend to display different geological and ecological patterns, we needed to verify whether terrestrial fragments and land-bridge islands share common patterns of response to habitat fragmentation. The land-bridge islands in the Thousand Island Lake, which were created by dam construction, are an ideal platform for the study of habitat fragmentation. To test bird sensitivity to habitat fragmentation across seasons, we conducted bird guild studies on 41 land-bridge islands in the Thousand Island Lake during the breeding season (April-June) and winter season (November-January) of each year between April 2009, and January 2012. We classified birds into guilds according to dietary type, foraging strata, and migratory status. We used an equation with logarithmic transformation from island biogeography, S=CAz, to clarify the relationship between bird guild species richness and island fragment area. In this equation, S represents species richness of each bird guild, A represents island area, C is a constant, and z is the slope of the species-area curve. This variable can be considered a measurement of sensitivity to habitat fragmentation. The bigger the value of z, the greater the sensitivity of the bird guild. We extracted and compared the slope of each species-area relationship curve (z value) to determine whether there exists significant variation in sensitivity to habitat fragmentation among the different bird guilds. Our research indicated that omnivorous birds were more sensitive to habitat fragmentation than insectivores during the winter season, while no significant difference was found for the breeding season. Understory birds were more sensitive to habitat fragmentation than canopy birds, both in breeding and winter seasons. Resident birds were more sensitive than migrants in winter, while no significant difference between them were observed in the breeding season. Both omnivorous and resident birds showed seasonal changes in their sensitivity to fragmentation. Other guilds, including insectivorous birds, canopy birds, understory birds, and migratory birds, showed no significant seasonal changes. Previous studies conducted in terrestrial fragments support our findings that responses of bird guilds to habitat fragmentation differ and that seasonal changes in the responses to habitat fragmentation do exist. These results may aid in the effective management of bird habitats and in the design of nature reserves. Future studies may focus on other bird guild types and determine if differences in responses to habitat fragmentation occur at a larger temporal scale. 参考文献 相似文献 引证文献

城市公园植被特征对陆生鸟类集团的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 城市公园植被特征对陆生鸟类集团的影响 DOI: 10.5846/stxb201311042667 作者: 作者单位: 华东师范大学;上海市城市化过程与恢复重点实验室,华东师范大学;上海市城市化过程与恢复重点实验室,华东师范大学;上海市城市化过程与恢复重点实验室,华东师范大学;上海市城市化过程与恢复重点实验室,上海市野生动植物保护管理站,上海市野生动植物保护管理站,上海市野生动植物保护管理站,上海科技馆,华东师范大学;上海市城市化过程与恢复重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 上海市绿化和市容管理局专项基金; 浦东新区科技发展基金(PKJ2011-N020); 上海市城市化生态过程与生态恢复重点实验室开放课题基金 The influence of vegetation structure on bird guilds in an urban park Author: Affiliation: East China Normal University,,,,,,,,East China Normal University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:城市公共绿地是城市生态系统中重要的鸟类栖息地,其植被特征对鸟类集团存在显著影响。在通过分析植被特征对陆生鸟类集团的作用,从而为公园合理配置植被来提高其作为野生动物栖息地的生态服务功能提供理论基础。2009 年10 月至2011 年10 月,采用样线法对上海滨江森林公园进行鸟类调查,利用主成分分析划分鸟类集团,用高度定义植被层次,用卡方检验分析鸟类行为在植被层次上的差异。结果表明,滨江森林公园陆生鸟类群落在乔木层的栖息行为和运动行为频次显著多于其在灌木层和地被层的行为频次,在地被层的取食行为频次显著多于其在乔木层和灌木层的行为频次。陆生鸟类可划分为8 个鸟类集团,鸟类集团之间存在栖息、运动和取食空间生态位的重叠。食虫拾取集团、杂食拾取集团、食肉飞取集团和植食拾取集团在栖息、运动和取食空间生态位上均存在较高的重叠度,其通过食性分离各自空间生态位。食虫探取集团和食虫飞取集团互为栖息空间生态位重叠度最高集团,其通过取食方式的不同来实现生态位的分离。根据公园植被特征对鸟类集团的影响结果对上海市公园绿地植被配置提出了建议。 Abstract:The acceleration of urbanization has led to a loss of biodiversity, which is a global ecological problem of great concern. Meanwhile, birds are useful indicators in monitoring environmental changes in urban ecosystem. Urban green areas have always been paid great attention because of their functions as natural habitats for many wildlife species. Bird guilds are groups of species that use environmental resources in similar ways. Therefore, we analyze the function of vegetation structure to bird community and bird guilds so that we make suggestions related to the design of urban green spaces in Shanghai. From October 2009 to October 2011, we set the line transect to survey the bird community in Shanghai Binjing Forest Park. According to the height of plant, we divided the habitat vegetation into three vertical levels including tree layer, shrub layer and ground layer. Chi-square test showed that there were significant differences among behaviors in three vegetation layers. The frequency of perching and moving in tree layer was more significant than that in other two layers and the frequency of feeding in ground layer was more significant than that in other two layers. According to the variables based on the location, feeding habits and foraging behavior pattern of birds, we classified 8 bird guilds including herbivorous collecting, herbivorous pecking, insectivorous collecting, insectivorous flying catching, insectivorous pecking, omnivorous collecting, omnivorous pecking and raptorial flying catching. There were differences and overlaps among the frequency of three behaviors of 8 bird guilds in three layers, so we considered there was niche overlap among 8 bird guilds. According to Morisita-Horn Index, the results indicated that insectivorous collecting guild, omnivorous collecting guild, flying catching guild and herbivorous collecting guild had high niche overlap of perching, and moving and feeding so these guilds reached niche separation by their diets. Insectivorous pecking guild and insectivorous flying catching guild had the most perching niche overlap with each other, and they reached niche separation by their foraging behavior patterns. Based on the results above, we concluded that trees were one of the most important vegetation components that enhance the bird species richness and diversity in urban green spaces because they provide roosting, nesting, hiding, and foraging sites. The shield function of shrub cover was confirmed to be an important habitat component and the ground layer provided food resources to bird community. The suggestion and recommendation in construction of urban parks was presented based on this study. The density and coverage of shrub layer should improve and large area of artificial lawn should be divided into several small pieces. We also discuss the conflicts between habitat for biodiversity maintenance and recreational function in urban parks. 参考文献 相似文献 引证文献

Waterbird Use of Catfish Ponds and Migratory Bird Habitat Initiative Wetlands in Mississippi

Abstract. Aquaculture can provide important surrogate habitats for waterbirds. In response to the 2010 Deepwater Horizon oil spill, the National Resource Conservation Service enacted the Migratory Bird Habitat Initiative through which incentivized landowners provided wetland habitats for migrating waterbirds. Diversity and abundance of waterbirds in six production and four idled aquaculture facilities in the Mississippi Alluvial Valley were estimated during the winters of 2011–2013. Wintering waterbirds exhibited similar densities on production (i.e., ∼22 birds/ha) and idled (i.e., ∼20 birds/ha) sites. A total of 42 species were found using both types of aquaculture wetlands combined, but there was considerable departure in bird guilds occupying the two wetland types. The primary users of production ponds were diving and dabbling ducks and American coots. However, idled ponds, with varying water depths (e.g., mudflats to 20 cm) and diverse emergent vegetation-water interspersion, attracted over 30 species...

Effects of land abandonment on bird communities of smallholder farming landscapes in post-war Croatia: implications for conservation policies

Land abandonment is a widespread phenomenon in agricultural systems, especially in former communist countries of Eastern and South-eastern Europe. Moreover, Croatia was affected by acts of war which enhanced the depopulation of marginal areas impelling further land abandonment. Agricultural landscapes in Croatia are highly parcelled with various proportions of for- est habitats due to traditional smallholder farming systems. Secondary successions as a consequence of land abandonment affect farmland birds that are among the most endangered bird species in Europe. We examined bird communities along a habitat gradient in heterogeneous agricultural landscapes. We used the share of woody vegetation cover as a proxy measure for land abandonment that we classified in four classes. Our results showed no significant Shannon Wiener Index differences of bird communities along the land abandonment gradient. However, there were differences in abundances when we examined bird guilds such as farmland, forest and "other" birds separately. However, the conservation value of each of the four land abandonment classes did not show significant differences. We extracted single bird species such as the Yellowhammer ( Emberiza citrinella), Red-backed Shrike (Lanius collurio), Song Thrush (Turdus philomelos) and European Robin (Erithacus rubecula) as potential indicator species for the four examined land abandonment levels. With these four species we successfully modelled the distribution of the recorded bird assemblages at the plot level along the four vegetation succession stages. We emphasized the need to develop new and inte- grative land use management concepts for areas affected by land abandonment in order to formulate sound conservation policy. Abbreviations: AMSL-Above Mean Sea Level; CLC-Corine Land Cover; DEM-Digital Elevation Model; MRPP-Multiple Response Permutation Procedure.

Can birds play a role as High Nature Value indicators of montado system?

Montados form a heterogeneous landscape of wooded matrix dominated by cork and/or holm oak with open areas characterized by fuzzy boundaries. Montado supports a high biological diversity associated to low intensity management and a landscape diversity provided by a continuous gradient of land cover. Among other features this permits the classification of montados as a High Nature Value (HNV) system. We assessed the role of birds as HNV indicators for montado, and tested several bird groups—farmland, edge, forest generalists and forest specialists species; and some universal indicators such as species conservation status, Shannon’s diversity index and species richness. Our study areas covered the North–South distribution of cork oak in Portugal, and we surveyed the breeding bird communities across 117 sampling sites. In addition to variables related to management and sanitary status, we considered variables that characterize the landscape heterogeneity inside the montado—trees and shrub density and richness of woody vegetation. Our results suggest that specific bird guilds can be used as HNV indicators of particular typologies of montado, and highlight the need to develop an indicator that could be transversally applied to all types of montado.

Do Nearctic migrant birds compete with residents at army ant raids? A geographic and seasonal analysis

ABSTRACT Army ant swarm raids in Neotropical montane forest are attended by diverse flocks of foraging birds that can include residents year-round and overwintering Nearctic migrants. We asked whether migrants and residents affect each other's ability to forage at army ant raids. We quantified variation in raid attendance by three guilds of birds: wintering migrants, regular and obligate raid attending residents (ant-following residents), and facultative raid attending residents. To test whether wintering migrants and residents were negatively associated at raids, we collected data on raid attendance in four adjacent life zones in the Tilaran Mountains of Costa Rica and in different seasons (when migrants were present and absent). We first compared the guilds' raid attendance among life zones. There was little geographic overlap of migrants and ant-following residents at raids, and raid attendance frequencies were strongly correlated with the estimated local abundances of these bird guilds in each life zo...

The influence of vegetation height heterogeneity on forest and woodland bird species richness across the United States.

Avian diversity is under increasing pressures. It is thus critical to understand the ecological variables that contribute to large scale spatial distribution of avian species diversity. Traditionally, studies have relied primarily on two-dimensional habitat structure to model broad scale species richness. Vegetation vertical structure is increasingly used at local scales. However, the spatial arrangement of vegetation height has never been taken into consideration. Our goal was to examine the efficacies of three-dimensional forest structure, particularly the spatial heterogeneity of vegetation height in improving avian richness models across forested ecoregions in the U.S. We developed novel habitat metrics to characterize the spatial arrangement of vegetation height using the National Biomass and Carbon Dataset for the year 2000 (NBCD). The height-structured metrics were compared with other habitat metrics for statistical association with richness of three forest breeding bird guilds across Breeding Bird Survey (BBS) routes: a broadly grouped woodland guild, and two forest breeding guilds with preferences for forest edge and for interior forest. Parametric and non-parametric models were built to examine the improvement of predictability. Height-structured metrics had the strongest associations with species richness, yielding improved predictive ability for the woodland guild richness models (r2 = ∼0.53 for the parametric models, 0.63 the non-parametric models) and the forest edge guild models (r2 = ∼0.34 for the parametric models, 0.47 the non-parametric models). All but one of the linear models incorporating height-structured metrics showed significantly higher adjusted-r2 values than their counterparts without additional metrics. The interior forest guild richness showed a consistent low association with height-structured metrics. Our results suggest that height heterogeneity, beyond canopy height alone, supplements habitat characterization and richness models of forest bird species. The metrics and models derived in this study demonstrate practical examples of utilizing three-dimensional vegetation data for improved characterization of spatial patterns in species richness.

Exploring co‐occurrence of closely‐related guild members in a fragmented landscape subject to rapid transformation

Quantifying biotic responses to landscape transformation is a major research focus. Most past studies have explored co‐occurrence of entire communities of a given group (e.g. birds) within largely intact ecosystems or over a limited time‐frame. By contrast, here we use data from a 15 yr experimental study, to explore intra‐guild co‐occurrence of six closely‐related and functionally‐similar sets of birds within 55 woodland fragments. Areas surrounding these remnants are undergoing transformation from grazed paddocks to Pinus radiata plantations, leading to a novel assemblage of forest and woodland birds. We sought to determine if the occurrence of a given species in a guild influenced the occurrence of other closely‐related species in that guild, and through this relationship whether there was evidence of co‐occurrence between species.After controlling for environmental and habitat variables which can affect species occurrence like time since commencement of landscape transformation, patch size and vegetation type, we found the occurrence of a given species was influenced by the occurrence of a closely‐related species in the same guild. Co‐occurrence varied among bird guilds and included: 1) positive co‐occurrence in which occurrence of one species within fragments positively affected the occurrence of another closely‐related guild member (e.g. eastern and crimson rosellas); and 2) negative co‐occurrence in which the occurrence of one species was negatively associated with the occurrence of another within the same guild (e.g. willie wagtail and grey fantail).We also identified interactions between patch size and species recording frequency within members of two guilds. For example, modelling of conditional recording frequency revealed the eastern rosella increased with increasing recordings of the crimson rosella in large patches, but decreased with increasing recordings of the crimson rosella in small patches.Our results provide empirical evidence of co‐occurrence among guild members and underscore the complexity of biotic responses to landscape transformation.

Structural heterogeneity increases diversity of non‐breeding grassland birds

Grassland birds have experienced greater population declines than any other guild of birds in North America, and yet we know little about habitat use and the affects of management during their non‐breeding period on wintering grounds. The paucity of information on wintering grassland birds limits our ability to develop effective conservation strategies. We investigated habitat use by the winter bird community in grasslands with restored heterogeneity resulting from the interactive effects of fire and grazing. We used 500 m line transects distributed across patches (i.e., <13, 13–24, and >24 months post disturbance) resulting from spring burning with growing season grazing (April‐Sept) and quantified avian relative abundance, community structure, and probability of patch occupancy while accounting for imperfect detection. Grassland structure that resulted from the fire‐grazing interaction created heterogeneity among patches that influenced avian habitat use during winter. Generalist birds such as the Savannah Sparrow (Passerculus sandwichensis) and meadowlarks (Sturnellaspp.) were relatively common in all patch types while more specialized species such as the Smith's Longspur (Calcarius pictus) and Le Conte's Sparrow (Ammodramus leconteii) reached greatest abundance and probability of occupancy in the patches with the least and greatest time post disturbance, respectively. This research provides novel information on the response of wintering birds to restored ecological processes in grasslands and can improve efforts to create effective conservation strategies. Our findings add to a growing body of literature supporting the use of fire and grazing to create a shifting grassland mosaic that increases vegetation structural and compositional heterogeneity and maximizes native biodiversity within rangeland ecosystems through the conservation of natural patterns and processes.

The relative importance of climate and vegetation properties on patterns of North American breeding bird species richness

Recent advances in remote sensing and ecological modeling warrant a timely and robust investigation of the ecological variables that underlie large-scale patterns of breeding bird species richness, particularly in the context of intensifying land use and climate change. Our objective was to address this need using an array of bioclimatic and remotely sensed data sets representing vegetation properties and structure, and other aspects of the physical environment. We first build models of bird species richness across breeding bird survey (BBS) routes, and then spatially predict richness across the coterminous US at moderately high spatial resolution (1 km). Predictor variables were derived from various sources and maps of species richness were generated for four groups (guilds) of birds with different breeding habitat affiliation (forest, grassland, open woodland, scrub/shrub), as well as all guilds combined. Predictions of forest bird distributions were strong (R2 = 0.85), followed by grassland (0.76), scrub/shrub (0.63) and open woodland (0.60) species. Vegetation properties were generally the strongest determinants of species richness, whereas bioclimatic and lidar-derived vertical structure metrics were of variable importance and dependent upon the guild type. Environmental variables (climate and the physical environment) were also frequently selected predictors, but canopy structure variables were not as important as expected based on more local to regional scale studies. Relatively sparse sampling of canopy structure metrics from the satellite lidar sensor may have reduced their importance relative to other predictor variables across the study domain. We discuss these results in the context of the ecological drivers of species richness patterns, the spatial scale of bird diversity analyses, and the potential of next generation space-borne lidar systems relevant to vegetation and ecosystem studies. This study strengthens current understanding of bird species–climate–vegetation relationships, which could be further advanced with improved canopy structure information across spatial scales.

Normalized difference vegetation index dynamic and spatiotemporal distribution of migratory birds in the Poyang Lake wetland, China

Spatiotemporal distribution of migratory birds in relation to phenological changes in wetland vegetation is significant in studying various ecological issues. In this study, SPOT-VGT imagery was used to monitor vegetation cover change in the Poyang Lake wetland. The Normalized Difference Vegetation Index (NDVI) served as an indicator to reveal vegetation change of the wetland. Spatiotemporal trends of the NDVI time series and distribution of migratory birds in the wetland from 1999 to 2009 were investigated. Migratory birds were classified based on their feeding guilds. The correlation coefficients between a time series of NDVI and different types of migratory birds were obtained.Our results show: (1) The inter-annual NDVI shows an uneven yet increasing trend since 2000, with the average NDVI ranging between 0.17 and 0.64. Its seasonal change is roughly in line with the seasonal variability of natural vegetative growth in the area. (2) Both the number of species present and the population of migratory birds show an increasing trend, and avian biodiversity has greatly increased. In most years herbivorous birds dominated over other foraging guilds. (3) The correlation between NDVI variability and bird population, usually above 0.5 in typical reservation zones, differs in reservation zones and for foraging guilds of migratory birds. NDVI was significantly correlated with the population of herbivorous birds. (4) Land-use types can influence this correlation through its reflection of different NDVIs. Wetland is positively correlated with bird population of all species, while cropland is negatively correlated.

Consistency and reciprocity of indirect interactions between tree species mediated by frugivorous birds

Despite the recognized importance of indirect plant–plant interactions for community structure, we still need to improve our current knowledge on how their outcomes are consistent in space and time, as well as reciprocal between participating species. These caveats are especially relevant in the case of indirect interactions mediated by animals, whose behavior may show high variability. We studied consistency and reciprocity of frugivore‐mediated interactions between fleshy‐fruited trees. For three years we examined the influence of crop size and neighborhood characteristics (con‐ and heterospecific fruit abundance and forest cover) on frugivory rates onCrataegus monogynaandIlex aquifolium, two coexisting species in the secondary forests of the Cantabrian range that share a guild of frugivorous birds. Crop size and neighborhood characteristics influenced frugivory onC. monogynaandI. aquifolium. Both con‐ and heterospecific fruit abundance affected frugivory, evidencing the occurrence of indirect interactions between trees, although the strength and sign of these effects varied between tree species as well as across years within species. By showing complex temporal patterns in the consistency and reciprocity of indirect interactions, this study emphasizes the need for multispecific, long‐term studies to assess the actual contribution of animal‐mediated plant–plant indirect interactions to community dynamics.