Response Of Bird Communities Research Articles

Drivers of the taxonomic and functional structuring of aquatic and terrestrial floodplain bird communities

ContextThere has been a limited amount of research which comparatively examines the local and landscape scale ecological determinants of the community structure of both riparian and aquatic bird communities in floodplain ecosystems.ObjectivesHere, we quantified the contribution of local habitat structure, land cover and spatial configuration of the sampling sites to the taxonomical and functional structuring of aquatic and terrestrial bird communities in a relatively intact floodplain of the river Danube, Hungary.MethodsWe used the relative abundance of species and foraging guilds as response variables in partial redundancy analyses to determine the relative importance of each variable group.ResultsLocal-scale characteristics of the water bodies proved to be less influential than land cover and spatial variables both for aquatic and terrestrial birds and both for taxonomic and foraging guild structures. Purely spatial variables were important determinants, besides purely environmental and the shared proportion of variation explained by environmental and spatial variables. The predictability of community structuring generally increased towards the lowest land cover measurement scales (i.e., 500, 250 or 125 m radius buffers). Different land cover types contributed at each scale, and their importance depended on aquatic vs terrestrial communities.ConclusionsThese results indicate the relatively strong response of floodplain bird communities to land cover and spatial configuration. They also suggest that dispersal dynamics and mass-effect mechanisms are critically important for understanding the structuring of floodplain bird communities, and should therefore be considered by conservation management strategies.

Response of an Avifaunal Community to the La Tuna Fire in the Verdugo Mountains of Southern California

In California’s coastal sage scrub and chaparral, fire reshapes the distribution of vegetation and the composition of bird communities, although the direction of the response in various habitats remains unclear. We investigated changes in the bird community at one site following the 2017 La Tuna Fire in the Verdugo Mountains of southern California. We found that the community’s diversity and evenness did not change, but the structure of foraging guilds did. Counts of omnivores and aerial and generalist foragers increased significantly, whereas counts of granivores and shrub foragers decreased. The number of insectivores decreased slightly, and ground foragers appeared unaffected. Principal components analysis suggests positive, neutral, and negative responses of birds associated with these guilds were driving differences in their abundances after the fire. We show how post-fire bird distributions may be related to fire severity, vegetation structure, and interspecific interactions. However, differences between our results and those of other studies suggest that patterns of bird community response to wildfire may be dictated by factors both related and unrelated to the fire over broader time scales.

Bird Community Responses to Restoration along Las Vegas Wash, Nevada

In a 12-year study of seasonal bird use along Las Vegas Wash (Clark County, Nevada), an area undergoing intensive channel stabilization and riparian and wetland restoration, we found that total bird abundance and species richness significantly increased. In the late phase of the project, total bird abundance was greatest during the nonbreeding season and winter transition, and species richness was greatest during the fall transition. Species associated with riparian shrubs decreased, likely as a response to large-scale removal of non-native shrubs and the lag in recovery of a native shrub understory. Species associated with trees and the mid-story had a mixed response, with detections of those species previously most closely associated with non-native trees showing a negative trend, while those associated with native overstory plants showing an increasing or mixed trend. Detections of wetland and aquatic species increased significantly throughout the project. This study shows differential restoration responses of species based on their natural history, seasons of primary use of the site, and the lag time in recovery of particular vegetation elements that are used by various species assemblages.

Bird community response to one decade of riparian restoration along the Colorado River delta in Mexico

We assessed the response of breeding birds to one decade of riparian restoration in the Colorado River delta including active vegetation management since 2010 and various environmental water deliveries since 2014. Bird surveys were conducted from 2002 to 2021 at 230 bird count stations distributed along five river reaches with different hydrogeomorphic characteristics, across 7 routes in actively revegetated (“restored”) sites, and 20 routes in non-actively revegetated (“control”) sites. Both restored and control sites could be affected by environmental flows/water deliveries. We examined the temporal trajectories of four community-aggregated metrics for 53 breeding species, and the number of detections (counts) for the 30 most frequently detected among the 53 species at the restored and control sites, using generalized linear mixed-effects models. Diversity and richness of the 53 breeding species were highest in the wettest river reach, but higher than in control sites in only one restored site within one of the driest river reaches. The avian community was recovering in control sites, ameliorating a long-term declining trend, perhaps indicating indirect positive effects of active restoration. The response to restoration of the 30 most common species was species-specific. Ten of the 16 riparian forest specialist species had more detections in restored sites of the wettest reach (vs. only two in the driest reach). Species with preference for agricultural fields and generalists had the highest counts along the entire delta. Generalists generally decreased following revegetation, which was another positive restoration effect. Our results will be used to help guide future restoration efforts.

Habitat-related bird community responses in northwest Panay, Philippines

Habitat-related bird community responses in northwest Panay, Philippines

Responses of bird communities to riparian park habitat factors: a case study in a highly urbanized area of Fuzhou city, China

Responses of bird communities to riparian park habitat factors: a case study in a highly urbanized area of Fuzhou city, China

Avian species functional diversity and habitat use: The role of forest structural attributes and tree diversity in the Midlands Mistbelt Forests of KwaZulu-Natal, South Africa.

Forest transformation has major impacts on biodiversity and ecosystem functioning. Identifying the influence of forest habitat structure and composition on avian functional communities is important for conserving and managing forest systems. This study investigated the effect of forest structure and composition characteristics on bird species community structure, habitat use and functional diversity in 14 Mistbelt Forest patches of the Midlands of KwaZulu-Natal in South Africa. We surveyed bird communities using point counts. We quantified bird functional diversity for each forest patch using three diversity indices: functional richness, functional evenness and functional divergence. We further assessed species-specific responses by focussing on three avian forest specialists, orange ground-thrush Geokichla gurneyi, forest canary Crithagra scotops and Cape parrot Poicephalus robustus. We found that bird community and forest-specialist species responses to forest structure and tree species diversity differed. Also, forest structural complexity, canopy cover and tree species richness were the main forest characteristics better at explaining microhabitat influence on bird functional diversity. Forest patches with relatively high structural complexity and tree species richness had higher functional richness. Different structural characteristics influenced habitat use by the three forest specialists. Tree species diversity influenced C. scotops and G. gurneyi positively, while P. robustus responded negatively to forest patches with high tree species richness. Our study showed that site-scale forest structure and composition characteristics are important for bird species richness and functional richness. Forest patches with high tree species diversity and structural complexity should be maintained to conserve forest specialists, bird species richness and functional richness.

Bird communities across different levels of human settlement: A comparative analysis from two northern Amazonian ecoregions

Urban ecosystems are increasingly dominating landscapes globally, so it is critical to understand the effects of human settlements on biodiversity. Bird communities are effective indicators because they are impacted by the size and expansion of human settlements, exemplified by changes in their habitat use, breeding and foraging behaviours, as well as patterns of richness and abundance. Existing studies on bird community responses to human settlements have mainly focused on single ecoregions and large cities, leaving a gap in comparative research on how differently sized human settlements affect bird communities across various ecoregions. To address this gap, we examine species richness, bird abundances and community composition in human settlements, which exhibit variable sizes, populations, landscape configurations, and overall intensity of settlement in two tropical ecoregions in Guyana, Amazonia: forest and savannah. In each ecoregion we explored how different groupings of urban tolerance in birds responded to human settlements of differing population size and building densities. Overall, we found significant differences in bird communities across the varying levels of human settlement intensity in both ecoregions, with greater differences in bird community composition in the forest ecoregion than the savannah region. In both ecoregions, species richness and abundance were highest at the medium level of settlement of human settlement. Our findings suggest that bird tolerance to human settlements varies based on ecoregion and site-level factors. In the savannah, built features may be benefitting birds from all urban tolerance levels, but they have a negative impact on less urban-tolerant species in the forest ecoregion. Our comparative analysis reveals for the first time that the impact of human settlements on avian communities in northern Amazonia varies among ecoregions, indicating that species evolved to live in a savannah may be more tolerant to human settlements than those more evolved to a forest system.

Responses of Bird Communities to Habitat Structure along an Aridity Gradient in the Steppes North of the Sahara

We explored the influence of habitat structure on bird density and species richness in the poorly known bird communities in the steppes of Eastern Morocco, along a 200 km long N–S gradient of increasing aridity. The birds were surveyed, and habitat structure was measured in 44 transects regularly distributed along the gradient and during the winter and spring seasons in two consecutive years. After applying a principal component analysis (PCA), five axes were identified, including one related to the latitude–altitude–soil-type gradient and another describing the development of herbaceous vegetation. Generalized linear models were used to explore the relations between bird density and species richness with PCA axes in each season, considering both the entire community and groups of granivorous, insectivorous, and mixed-diet species. More than 90% of the birds were year-round residents, with larks dominating the community in both seasons. We conclude that a distinct multifactorial response can be identified for each functional group of species. In the winter, the community is mainly affected by the structure of the habitat, while aridity (and its assumed relation to primary production) is less influential. In the spring, habitat structure continues to have the greatest explanatory power, but location along the aridity gradient becomes more relevant. These findings reveal the interaction of the negative effects of climatic and anthropogenic changes in the habitat available to these bird communities, with a greater impact expected on birds with diets that include seeds, as well as a general shift of optimal breeding conditions toward more northerly latitudes.

EVI and NDVI as proxies for multifaceted avian diversity in urban areas.

Most ecological studies use remote sensing to analyze broad-scale biodiversity patterns, focusing mainly on taxonomic diversity in natural landscapes. One of the most important effects of high levels of urbanization is species loss (i.e., biotic homogenization). Therefore, cost-effective and more efficient methods to monitor biological communities' distribution are essential. This study explores whether the Enhanced Vegetation Index (EVI) and the Normalized Difference Vegetation Index (NDVI) can predict multifaceted avian diversity, urban tolerance, and specialization in urban landscapes. We sampled bird communities among 15 European cities and extracted Landsat 30-meter resolution EVI and NDVI values of the pixels within a 50-m buffer of bird sample points using Google Earth Engine (32-day Landsat 8 Collection Tier 1). Mixed models were used to find the best associations of EVI and NDVI, predicting multiple avian diversity facets: Taxonomic diversity, functional diversity, phylogenetic diversity, specialization levels, and urban tolerance. A total of 113 bird species across 15 cities from 10 different European countries were detected. EVI mean was the best predictor for foraging substrate specialization. NDVI mean was the best predictor for most avian diversity facets: taxonomic diversity, functional richness and evenness, phylogenetic diversity, phylogenetic species variability, community evolutionary distinctiveness, urban tolerance, diet foraging behavior, and habitat richness specialists. Finally, EVI and NDVI standard deviation were not the best predictors for any avian diversity facets studied. Our findings expand previous knowledge about EVI and NDVI as surrogates of avian diversity at a continental scale. Considering the European Commission's proposal for a Nature Restoration Law calling for expanding green urban space areas by 2050, we propose NDVI as a proxy of multiple facets of avian diversity to efficiently monitor bird community responses to land use changes in the cities.

Bird community responses to urbanization in a medium-sized Argentine city: Santo Tomé (Santa Fe Province) as a case study


 
 
 Urbanization transforms the landscape and consequently affects biodiversity. Cities are heterogeneous landscapes due to a differential distribution of human activities, infrastructure, and vegetation composition. Bird assemblages vary according to such variations. In Argentina, assessments of the effect of urbanization on bird assemblages come from large capital cities, whereas in intermediate-size cities studies are scarce. Intermediate-size cities present higher growth rates than capital cities. Studies on the effect of Urban Land Uses (ULU) can contribute to the planning of urban growth. We evaluated the variation in taxonomic diversity of bird assemblages at different ULUs in Santo Tomé, an Argentine city of 66 133 inhabitants. We performed bird counts in seven ULUs (the centre, the suburban sector, the peri-urban sector, small urban parks, the military base, the riverside walkway, and the urban reserve). In each ULU, we located 10 transects of 100 m long x 50 m wide. In each transect we recorded bird species and their abundance and the number of pedestrians and vehicles. Taxonomic diversity varied among the different ULUs. The centre presented the lowest richness and diversity, in contrast to the highest values for these variables found in the riverside walkway and the urban reserve. The rest of the ULU presented intermediate levels of richness and diversity. The structure and composition of bird assemblages varied among ULUs. Our study reinforces the importance of ULU characterized by high vegetation cover, low levels of human activity, and with vegetation management for conservation purposes.
 
 

Coastal bird community response to dredge‐spoil tidal marsh restoration at New Round Island, Mississippi, U.S.A.

The northern Gulf of Mexico has been the focus of many coastal habitat restoration projects in the wake of new funding streams stemming from the settlement of the 2010 Deepwater Horizon oil spill litigation. One such project was the creation of New Round Island (RNDI) in Mississippi, a 86 ha island created using dredge material in 2017. The island design incorporated a novel U‐shaped sand berm with multiple interconnected containment sells. In this study we sought to document changes in relative abundance of various coastal bird species. We conducted surveys for breeding and nonbreeding birds from June 2017 to May 2021, and we conducted nonbreeding surveys at two reference sites for comparison. Breeding bird numbers were dominated by colonial nesting species in years 1 and 2, which subsequently declined as vegetation cover increased. Solitary nesting species increased over time, with Wilson's Plover (Charadrius wilsonia) nest count increasing from zero in year 1 to 29 in year 5. Nonbreeding shorebird counts peaked in years 1–2 and subsequently declined, although shorebird counts also decreased at the reference sites. Relative abundance of waders (Ardeidae), rallids (Rallidae), and passerines (Passeriformes and allies) increased in comparison to reference sites. This study demonstrates the short‐term benefits of this U‐shaped island design to early‐succession breeding species and nonbreeding shorebirds shortly after construction, with longer‐term benefits to breeding Wilson's Plover and to marsh birds as vegetation fills in.

Functional group‐dependent responses of forest bird communities to invasive predator control and habitat fragmentation

AbstractAimMounting global pressure on bird populations from invasive predators and habitat loss has driven a rapid growth in restoration and conservation action around the world, yet the efficacy of such actions is still not well understood. We investigated the relative and interactive effects of invasive predator control and habitat fragmentation on the abundance of native birds and invasive mammalian predators in native forest fragments.LocationWaikato region, New Zealand.MethodsWe sampled invasive mammalian predator and native bird abundances using camera traps and bird counts at 26 sites in 15 forest fragments across New Zealand's Waikato region. Fragment area, shape complexity and surrounding land cover of exotic and native forest were determined in ArcMap. We further created two composite gradients reflecting predator control intensity and temporal distribution of control based on seven quantitative variables recorded in each of the 5 years preceding data collection. Finally, we estimated the relative influence of these drivers on invasive mammals and functional groups of native birds using model averaging.ResultsBoth the intensity and temporal distribution of invasive predator control significantly affected invasive predator abundance. Landscape and fragment structure were often equally important drivers of invasive predator abundances, but responses varied among invasive mammal species. Both invasive predator control intensity and fragment structure were similarly important drivers of native bird abundance, though bird community responses varied markedly between functional groups.Main conclusionsOur findings suggest that spatial extent of invasive predator control and fragment area constrain invasive predator numbers and enhance bird abundance, especially for small insectivorous species, whilst other aspects of habitat fragmentation are less important for invasive mammals but at least as important for native bird communities. Consequently, both drivers should be given strong consideration when undertaking landscape‐scale conservation and restoration of bird communities in human‐altered landscapes threatened by invasive predators.

Rainforest bird communities threatened by extreme fire

Fire occurs naturally in many ecosystems and is predicted to increase in frequency and severity with climate change. The 2019–2020 Australian bushfire season was extreme, unprecedented in scale and severity, burning almost 19 million ha. This included half of the Gondwanan rainforests in eastern Australia, an ecosystem with no documented record of fire. We investigated the recovery of rainforest bird communities one-year post fire, using 80 bird and vegetation surveys within and adjacent to Gondwanan rainforests. We compared bird communities in burnt and unburnt non-fire prone rainforests and burnt and unburnt fire prone dry sclerophyll forests. Bird diversity was lower in burnt rainforests than unburnt rainforests, but the inverse was true for dry sclerophyll forests. 12 functional groups responded to differences in forest type and fire history, including frugivores, folivores, and insectivores which may be more vulnerable in burnt rainforest. We identified a further 10 functional groups where variation related to vegetation structure, reflecting forest types and fire histories. Finally, we estimated that four species were more common in unburnt rainforest than burnt rainforest, while three species were more common in burnt rainforests than unburnt rainforests. In dry sclerophyll forests, one species was more common in burnt and one more common in unburnt. The responses of bird communities to the extreme 2019–2020 fires highlighted the vulnerability of rainforests to fire compared with more fire-prone ecosystems. To protect species and functional diversity of rainforests from the growing risk of fire with climate change, local fire mitigation management may be needed.

Comparison of bird diversity between temperate floodplain forests and urban parks

Biodiversity in urban green areas has been widely explored in several bird studies because birds are known to be important bio-indicators. Many studies have investigated the different responses of bird communities to urbanization and land use changes in urban environments. However, there are still important knowledge gaps related to the impacts of the heterogeneity, spatial structure, and connectivity of green areas on avian diversity. Such information is needed for sustainable urban planning. In this study, we focused on the comparison of bird communities between urban parks in the heritage city of Olomouc and hardwood floodplain forests in the vicinity of the city. The results of the study indicate the high importance of urban parks for the maintenance of bird diversity even though urban parks are man-made habitats. The results highlight the importance of some native vegetation structures in urban parks (old trees, bush ecotones) for maintaining urban bird biodiversity. Some implications of the results can be widely used as a decision support tool for the management of urban green areas and for the planning of ecological networks in urban landscapes.

Response of bird community to gradual landscape transformation in Darmaga campus, IPB University, Bogor, Indonesia

When a landscape gradually transforms, the bird community that inhabits the landscape will also adapt and change accordingly. Long-term data on the bird-habitat relationship, however, is still lacking in the sub-urban tropical areas. The objective of this paper was to analyze the response of bird community along with the gradual transformation of the landscape. Darmaga Campus of IPB University (± 2.67 km2) was selected as the study area due to its landscape transformation for campus development/construction, and the availability of bird monitoring data. Data on landscape transformation were gathered from the IPB building construction book published in 2017, and bird community (1982-2020) were gathered from published reports and papers. During the observed period, Darmaga Campus that initially consisted mostly of old rubber plantation has been gradually transformed into various academic-related uses, such as some areas for buildings dan field laboratories. From 1982 to 2020, the cumulative bird species in the study area at least was 124 species. During the observed years, the bird community was highly dynamics (bird species number in 1982 = 41 species, 1985 = 39 species, 1986 = 68 species, 1991 = 68 species, 2001 = 39 species, 2003 = 72 species, 2013 = 52 species, 2020 = 99 species). New incoming species were Chestnut-winged Cuckoo, Asian Brown Flycatcher, Tiger Shrike, and babblers (e.g., Black-capped Babbler); Brown Shrike, White-rumped Shama, Oriental Magpie-Robin and Green Junglefowl have not been observed or have become increasingly rare in the last ten years. Meanwhile, Red-breasted Parakeet, Fulvous-breasted Woodpecker, Sunda Pygmy Woodpecker, Black Drongo, and Sooty-headed Bulbul are always present species. Bird species such as Orange-headed Thrush, White-rumped Shama, White-browed Shortwing, and Velvet-fronted Nuthatch are species that entered to rarely found species. Gradual landscape transformation, from an old rubber plantation into a mosaic of small patches of human-made ornamental plants, shrub, and tree plantation, turns out to be beneficial for some bird species, but could also disadvantageous for others, causing a dynamic bird community composition.

Ecological Correlates of Elevational Range Shifts in Tropical Birds

Globally, birds have been shown to respond to climate change by shifting their elevational distributions. This phenomenon is especially prevalent in the tropics, where elevational gradients are often hotspots of diversity and endemism. Empirical evidence has suggested that elevational range shifts are far from uniform across species, varying greatly in the direction (upslope vs. downslope) and rate of change (speed of elevational shift). However, little is known about the drivers of these variable responses to climate change, limiting our ability to accurately project changes in the future. Here, we compile empirical estimates of elevational shift rates (m/yr) for 421 bird species from eight study sites across the tropics. On average, species shifted their mean elevations upslope by 1.63 ± 0.30 m/yr, their upper limits by 1.62 m ± 0.38 m/yr, and their lower limits by 2.81 ± 0.42 m/yr. Upslope shift rates increased in smaller-bodied, less territorial species, whereas larger species were more likely to shift downslope. When considering absolute shift rates, rates were fastest for species with high dispersal ability, low foraging strata, and wide elevational ranges. Our results indicate that elevational shift rates are associated with species’ traits, particularly body size, dispersal ability, and territoriality. However, these effects vary substantially across sites, suggesting that responses of tropical montane bird communities to climate change are complex and best predicted within the local or regional context.

Fire and functional traits: Using functional groups of birds and plants to guide management in a fire‐prone, heathy woodland ecosystem

AbstractAimMany dry forests and woodlands worldwide are fire‐prone and support bird and plant communities shaped by fire. Changes in fire regimes, including the time between fires, have important implications for population trajectories. We studied the responses of bird and plant communities of heathy woodlands to time since the last fire, a key measure underpinning fire management, to evaluate whether current management strategies will enhance conservation of multiple taxa.LocationOtway Ranges, south‐eastern Australia.MethodsWe surveyed birds and plants at 38 sites, stratified by an 80‐year post‐fire chronosequence, and modelled the responses of individual species, functional groups and community composition to fire history. Model outputs were used to evaluate the impacts of fire management as guided by (a) domains of tolerable fire intervals, a concept based on plant life history traits, and (b) the spatial arrangement of post‐fire age classes, a surrogate for animal habitats.ResultsBird and plant communities both responded to time since fire. Notable relationships included the following: a high reporting rate of ground‐foraging birds and high cover and species richness of shrubs immediately after fire; and a gradual increase up to ~50 years and ~20 years post‐fire of birds that forage in the mid‐storey and facultative‐resprouting plants, respectively. Post‐fire age classes had distinct bird and plant assemblages. Tolerable fire intervals currently used by land managers (min 12–max 45 years between fires) encompassed the peak in richness of most plant functional groups but not the preferred habitat of lower‐mid‐storey foraging birds.Main conclusionsFire management based solely on birds or plants risks population declines in other biota. Use of functional groups can help guide strategic planning, such as spatial representation of post‐fire age classes across the landscape. Maintaining late‐successional vegetation will provide habitat for several groups of birds, while fire is needed at sufficient frequency to prevent loss of plants and ground‐foraging birds.

Exurbia East and West: Responses of Bird Communities to Low Density Residential Development in Two North American Regions

Exurban development is a prevalent cause of habitat loss and alteration throughout the globe and is a common land-use pattern in areas of high natural amenity value. We investigated the response of bird communities to exurban development in two contrasting North American regions, the Adirondack Park (New York) in the eastern US, and the Greater Yellowstone Ecosystem (Montana) in the Rocky Mountain West. We combined social and ecological data collection methods to compare the effects of exurban development on avian communities between the two landscapes, and, in exurban residential areas within them, to compare the relative roles of habitat structure, resource provisioning, and human disturbance in influencing avian habitat use. Contrasting with an earlier pilot study, we found differential effects of exurban development in the two regions, with birds generally more responsive in the Adirondack Park. Characteristics of habitat context and structure had larger influences on bird habitat use than human-associated resource provisioning or disturbance in both landscapes. The smaller magnitude and high variability in the responses of birds to landowner stewardship and/or disturbance suggest that broader geographical factors are highly important and that careful siting of developments on the landscape may be more successful at protecting wildlife communities than attempts to influence the behaviors of their inhabitants once built.

How do habitat amount and habitat fragmentation drive time-delayed responses of biodiversity to land-use change?

Land-use change is a root cause of the extinction crisis, but links between habitat change and biodiversity loss are not fully understood. While there is evidence that habitat loss is an important extinction driver, the relevance of habitat fragmentation remains debated. Moreover, while time delays of biodiversity responses to habitat transformation are well-documented, time-delayed effects have been ignored in the habitat loss versus fragmentation debate. Here, using a hierarchical Bayesian multi-species occupancy framework, we systematically tested for time-delayed responses of bird and mammal communities to habitat loss and to habitat fragmentation. We focused on the Argentine Chaco, where deforestation has been widespread recently. We used an extensive field dataset on birds and mammals, along with a time series of annual woodland maps from 1985 to 2016 covering recent and historical habitat transformations. Contemporary habitat amount explained bird and mammal occupancy better than past habitat amount. However, occupancy was affected more by the past rather than recent fragmentation, indicating a time-delayed response to fragmentation. Considering past landscape patterns is therefore crucial for understanding current biodiversity patterns. Not accounting for land-use history ignores the possibility of extinction debt and can thus obscure impacts of fragmentation, potentially explaining contrasting findings of habitat loss versus fragmentation studies.