Bird Communities Research Articles

Using participatory scenario planning to explore the synergies and trade‐offs from upland treescape expansion

Abstract The future of land use in the UK uplands is highly debated, with growing interest in increasing tree cover and other land use changes, alongside a desire to maintain traditional land use patterns and practices. Treescape expansion is likely to result in synergies and trade‐offs between different outcomes, so integrating stakeholder preferences into future scenarios will be important for understanding social acceptance or conflicts and for promoting pathways towards sustainable land use in the future. We used Participatory Scenario Planning to create spatially explicit land use and tree cover scenarios to 2050 in two UK upland landscapes (the North Pennines & Dales in England and the Elenydd in Mid Wales). Stakeholders were asked to list their preferred land use interventions, along with spatial criteria determining their preferred location in the landscape. We then created future scenarios and modelled the impact on greenhouse gas emissions, livestock numbers, timber production, recreation, water run‐off and bird populations. Stakeholder‐led scenarios resulted in an increase in total tree cover from 2.5% to 3.3%–9.7% in the North Pennines & Dales, and from 9.7% to 10.1%–26.8% in the Elenydd. With increasing tree cover, we found positive impacts on greenhouse emissions and water run‐off (both of which declined), woodland birds and nature‐based recreation (both of which increased) and mixed outcomes on timber. On the contrary, increasing tree cover was associated with a reduction in livestock numbers and upland birds. The potential decline of upland bird communities was of particular concern to all stakeholder groups that saw a decline in their scenario. Our methodology provides unique insights into stakeholder‐preferred treescape expansion, which could be expanded to other landscapes and additional interests. Further work should disentangle how future land use scenarios could reduce trade‐offs while still delivering synergies to other ecosystem services. Read the free Plain Language Summary for this article on the Journal blog.

Keystone effects of prairie dogs (Cynomys spp.) on grassland birds: Current knowledge and future directions

AbstractKeystone species are critical to maintaining ecological relationships and ecosystem functioning around the world. Prairie dogs (Cynomys sp.) are a genus of colonial keystone species endemic to North American grasslands that modify bird community composition via ecological disturbance, but this topic has not been reviewed despite many studies on grassland bird associations with prairie dogs. We conducted a systematic literature review (n = 111 studies) where we assessed three hypotheses and found consistent support for each: (1) prairie dogs increase abundance of early‐successional grassland birds through grazing, (2) prairie dog towns modify bird community composition compared to nearby grassland because they increase heterogeneity within grasslands at large spatial scales, and (3) prairie dogs increase raptor abundance by serving as a prey base. Significant gaps in our understanding of the effects of prairie dogs on birds remain. Most research was conducted on black‐tailed prairie dogs during the bird breeding season and focused on how prairie dogs modify the occurrence and abundance of birds. Research is needed on the effects of other prairie dog species, effects on birds during the non‐breeding or migratory seasons, and effects on demography, particularly for songbirds. Continued work on this topic can increase our understanding of how keystone species affect bird communities and inform conservation of grassland birds globally. Due to rapid declines of grassland birds in North America, we suggest conserving prairie dog towns as vital sources of early successional grassland and habitat heterogeneity.

Intrinsic factors influence a physiological measure in a forest bird community: adults and females have higher H/L ratios than juveniles and males

Physiological parameters have the potential to serve as valuable early warning indicators for the conservation of animal populations. However, measuring physiological adaptations in wildlife is often challenging, due to intrinsic differences causing natural variations of physiological measures between individuals across species. This study is aimed at addressing this by investigating the influence of intrinsic factors, including sex, age, body condition, and the incubation of eggs on the H/L ratio of a forest bird community. As physiological measure, we used the heterophil to lymphocyte (H/L) ratio of individuals belonging to different species in the forest bird community, which was assessed using a novel deep learning approach based on convolutional neural networks (CNNs) applied to whole blood smear scans. Using phylogenetically controlled Bayesian analyses across the bird species, we found higher H/L ratios in adult birds than in juveniles and observed slightly higher H/L ratios in females than in males. While body condition had no effect on the H/L ratio, incubating birds tended to have higher H/L ratios than non‐reproductive birds, regardless of their sex. Furthermore, we found a robust phylogenetic signal of the H/L ratio in the studied bird community. Our results reveal significant general patterns of the effect of intrinsic factors on the H/L ratio across a bird community.

Disentangling the relative effects of semi-natural habitats within different landscape agricultural intensities on bird communities

Disentangling the relative effects of semi-natural habitats within different landscape agricultural intensities on bird communities

Increase in disturbance-induced canopy gaps leads to reorganization of Central European bird communities

Increase in disturbance-induced canopy gaps leads to reorganization of Central European bird communities

Composition of breeding bird communities under different intensities of human activity: A case study in Jiulingshan Nature Reserve in eastern China

Composition of breeding bird communities under different intensities of human activity: A case study in Jiulingshan Nature Reserve in eastern China

Landscape features outside the airport exerted direct and indirect impact on bird community characteristics inside the airport

Landscape features outside the airport exerted direct and indirect impact on bird community characteristics inside the airport

A tale of two worlds: spatial arrangement of avian communities in a Neotropical city

Urbanization is considered one of the most critical processes related to biodiversity loss worldwide. Birds are one of the most commonly studied groups in urban ecosystems due to their quick response to environmental changes. Despite the current knowledge related to urban bird communities, information associated with the specific factors shaping avian communities in cities is still scarce, especially in the Neotropics. In this study, we performed a citywide survey for birds in the city of Xalapa (Mexico), to compare the species composition of urban communities with those of two reference sites adjacent to the urban area. We hypothesized that the compositional similarity would either be defined by their spatial proximity to their respective reference site or that it would be shaped by resources intrinsic to the city. Considering the nature of our data, we performed a subgroup analysis using randomly selected groups for the urban and reference sites to compare similar samples. We used Sørensen (incidence-based) and Bray-Curtis (abundance-based) cluster analyses and found that the urban bird community composition is better explained by the vegetation cover than by the proximity to the reference sites. We confirmed this association with the results of the GLM, showing a statistically significant association with the vegetation cover. Our results are relevant in terms of urban design, considering that promoting the improvement of vegetation in cities could potentially help avian communities in these changing environments.

Effects of Vegetation on Bird Communities and Bird–Plant Interactions in Urban Green Areas of Riparian Forests in Brazil That Have Undergone Ecological Restoration

Urbanization replaces natural vegetation for city expansion, impacting environmental and climatic variables that affect the health of the human population and fauna. These changes affect important groups such as birds, given their greater sensitivity to anthropogenic alterations, especially when we understand these effects on a large scale, considering countries such as Brazil, which represents the third country with the greatest diversity of bird species in the world. Conversely, green spaces like urban parks, tree-lined avenues, and riparian forests seem to foster biodiversity conservation. Here, we analyze the effects of vegetation on bird communities and bird–plant interactions in urban riparian areas that have undergone ecological restoration. The study was carried out between January and October 2019 in two restored urban areas of Uberlândia, Brazil. Results showed that the richness of birds observed between the two areas was Praia Clube (n = 86) and Parque Linear Rio Uberabinha (n = 80). The most representative trophic guilds in the areas, with the highest proportion in their relative abundances during both seasons, were granivores, omnivores, insectivores, and frugivores. Composition varied significantly between areas as a function of the plant community, particularly when considering the interaction between season and area (ANOSIM: R = 0.19; Stress = 0.10; p = 0.008). In environments dominated by generalist and synanthropic species (Eared Dove, Picazuro Pigeon), effective planning and management of green areas are crucial. It is important to acknowledge that certain bird species depend on specific habitats, such as riparian forests, and that specific plant species within these areas are vital for specialized bird species, such as species endemic to the Brazilian Savanna or Cerrado and restricted to Brazil (White-striped Warbler) and species in vulnerable categories globally (Bare-faced Curassow). Therefore, restoration efforts in degraded areas should be carefully planned to restore interactions and conserve biodiversity effectively.

Lower Bird Evenness and Diversity Are Associated With Higher Usutu Prevalence in Culex pipiens Mosquitoes

ABSTRACTIntroductionThe mosquito‐transmitted Usutu virus has spread in the last few years, becoming endemic in several areas of Europe, such as in the southern French region of the Camargue. Our aim was to study the relationships between the presence of the viral agent in Culex mosquitoes and the structure of bird communities in the context of the dilution effect.MethodsWe carried out mosquito and bird censuses in several selected localities across a land‐use gradient and screened mosquito pools for flaviviruses. We focused on exploring how host bird diversity, richness, abundance and evenness were associated with Usutu detection in Cx. pipiens.ResultsUsutu virus was detected in seven pools of Cx. pipiens, and phylogenetic analysis identified Usutu lineage Africa 3, confirming its circulation. The probability of detection in mosquitoes is associated with areas with lower bird evenness and diversity but higher bird abundance and richness and higher Cx. pipiens abundances.ConclusionsBird evenness was the variable with the greatest explanatory power, being negatively related to the probability of detecting Usutu in Cx. pipiens, supporting a dilution effect. These results will help us better understand the relationships between bird community structure and the risk of Usutu mosquito‐borne disease.

Characterization of bird communities in four riparian habitats along the Sinaloa River, northwest Mexico

ABSTRACT This study characterizes the species diversity, richness, composition, and structure of avifauna in four riparian habitats (Bamoa, La Criba, Malecon, and Estero) along the Sinaloa River in northwest Mexico. The research was conducted from March to November 2024, employing the strip transect method and fixed-radius point count method for the bird survey. Data were analysed using the Shannon-Wiener, Simpson, and Margalef indices, relative abundance index, and Jaccard similarity coefficient. A total of 146 species were recorded across 19 orders and 47 families, with the order Passeriformes being the most represented. The Estero habitat exhibited the highest diversity and species richness, while Bamoa and La Criba showed the greatest similarity. The most abundant species were generalists adapted to human-altered environments (Zenaida asiatica, Tachycineta albilinea, Quiscalus mexicanus, and Passer domesticus). This study provides essential data for future conservation strategies in riparian ecosystems.

Poles apart: the structure and composition of the bird community in bamboo in the Eastern Himalaya

Poles apart: the structure and composition of the bird community in bamboo in the Eastern Himalaya

INFLUENCIA DE LAS ÁREAS GANADERAS SOBRE LAS COMUNIDADES DE AVES EN EL NORTE DE VERACRUZ, MÉXICO

<p><strong>Background.</strong> Livestock activities generate changes in ecosystems that impact bird communities, which fulfill diverse ecological functions such as pollination, fruit and seed dispersal, and biological control of insects and/or pests. <strong>Objective.</strong> To characterize the community of birds in a livestock landscape in northern Veracruz. <strong>Methodology.</strong> From 2020 to 2021, 144 visits were made to live fences (CV; n = 3) and cattle pastures (PA; n = 3), where the fixed-radius point count technique was used to identify and count the birds present. <strong>Results.</strong> A total of 6,450 individuals and 107 species were recorded. In general, the CVs were more diverse than the PAs, although the PAs were more dominant. The importance value index reflects that in the VCs the importance of the species is similar, while in the PAs certain species stand out, however, at the level of trophic guilds, insectivorous birds dominate. Through a canonical correspondence analysis, three community assemblages were distinguished: one station in the VCs, one station in the APs and the rest of the stations. <strong>Implications.</strong> The work suggests further studies that will allow us to know why birds are using these man-made livestock systems. <strong>Conclusion.</strong> The live fences obtained greater diversity, so it is necessary to integrate more trees within the pastures to increase the ecological functions, such as the control of insects through insectivorous birds.</p>

Monitoring Grassland Bird Communities with Acoustic Indices

Monitoring Grassland Bird Communities with Acoustic Indices

A 50-Year Perspective on Changes in a Pacific Northwest Breeding Forest Bird Community Reveals General Stability of Abundances

Abundances of breeding forest birds have apparently declined in North America during the last five decades, possibly influenced by anthropogenic effects. We re-surveyed breeding birds in coniferous woodland plots initially surveyed in the late 1960s in western Oregon, USA. We aligned methods with those originally used and incorporated modern methods to estimate densities. To relate local results to regional trends, we compared them with Breeding Bird Survey (BBS) data. We assessed potential drivers of change for species exhibiting strong differences by relating bird density to changes in habitat and landscape composition. Eighty percent of species had densities similar to 50 years ago. Five of sixty-four species declined statistically significantly. Declines were poorly explained by changes in vegetation structure or landscape cover composition. Thirty-one species were apparently stable on plots but declined in the region. For a few species, comparisons of estimates should be viewed with caution as density estimates based on the original method were unusually high or low. Our modern estimates typically had measurement errors encompassing the 1960s estimates of density. We conclude that this Pacific Northwest bird community has remained similar through time despite 50 years of intensive forest management, indicating resilience to this level of anthropogenic activity.

Urban gradient resolution matters! Avian diversity patterns in a boreal green city

Urbanization is a prominent driver of environmental change worldwide, profoundly impacting biodiversity dynamics. While much research has originated from large urban areas in temperate regions, medium-sized boreal cities remain relatively understudied. By following a citywide survey approach, we studied the impact of urbanization intensity gradient resolution on bird diversity in Lahti, Finland, a green boreal city. While one of the urbanization intensity gradients (four-category gradient) showed no significant differences in species richness, the more detailed resolution (ten-category gradient) revealed a decline in species richness within the most urbanized categories, albeit such decline was not pronounced, probably due to the extensive green cover of the city. Species identity analyses confirmed distinct bird community compositions at 50% built cover threshold for both gradient resolutions. Our analyses identified key variables related to bird species richness on the site level, highlighting the positive correlation with tree cover and negative correlations between built cover and noise level with recorded bird species richness. These findings expose the intricate interplay of habitat variables in shaping bird diversity in urban environments. Moreover, the results of this study emphasize the importance of detailed resolutions when assessing urbanization gradients, particularly in less biodiverse regions. Finally, we show the pivotal role of citywide surveys in providing a comprehensive understanding of urban biodiversity, allowing for precise categorization and comparison of conditions within the city. This approach provides valuable insights for urban planning and conservation efforts in boreal climatic regions.

Remotely Sensed Spectral Indices as Proxies of the Structure of Urban Bird Communities

Abundant and diverse urban bird communities promote ecosystem and human health in cities. However, the estimation of bird community structure requires large amounts of resources. On the other hand, calculating remotely sensed spectral indices is cheap and easy. Such indices are directly related to vegetation cover, built-up cover, and temperature, factors that also affect the presence and abundance of bird species in urban areas. Therefore, spectral indices can be used as proxies of the structure of urban bird communities. We estimated the abundance, taxonomic, functional, and phylogenetic diversity of the bird community at each of 18 50 m radius survey stations in the urban core area of Kavala, Greece. We also calculated eight spectral indices (means and standard deviations, SDs) around survey stations at 50 m, 200 m, and 500 m spatial scales. The land surface temperature SD (LST) was the most important proxy, positively related to bird abundance at the 50 m and 200 m spatial scales. At the same time, the mean green normalized difference vegetation index (GNDVI) was the most important proxy, negatively related to abundance at the 500 m spatial scale. Means and SDs of vegetation indices, such as the normalized difference vegetation index (NDVI), enhanced vegetation index (EVI2), soil-adjusted vegetation index (SAVI), and atmospherically resistant vegetation index (ARVI), were the most important proxies, positively related to taxonomic and functional diversity at all the spatial scales. The mean and SDs of LST, normalized difference moisture index (NDMI), and normalized difference built-up index (NDBI) variously affected taxonomic and functional diversity. The mean and SDs of LST were the best proxies of phylogenetic diversity at the 50 m and 500 m spatial scales, while the SDs of NDBI and NDMI were the best proxies at the 200 m spatial scale. The results suggest that several spectral indices can be used as reliable proxies of various facets of urban bird diversity. Using such proxies is an easy and efficient way of informing successful urban planning and management.

Integrating Functional and Phylogenetic Diversity to Assess Bird Community Assembly Along the Major Rivers of Hainan Island, South China.

Understanding the mechanisms associated with community assembly can contribute to explaining the formation and maintenance of biodiversity patterns. In this study, we used the line transect method to survey breeding birds along the three major rivers of the Nandu River, Changhua River and Wanquan River on Hainan Island, south China. The patterns of community assembly were subsequently assessed by integrating functional and phylogenetic diversity, whereas environmental factors and interspecific competition intensity were incorporated to determine whether community assembly in these rivers is driven by environmental filtering or interspecific competition. Our findings revealed that bird communities within rivers were characterized by an overall slight clustering (i.e., more similar species), with the upper reaches of the Changhua River and the lower reaches of the Nandu River showing over-dispersion, whereas the lower, middle, and upper reaches of the Wanquan River all showed clustering. Altitude and the human influence index were identified as the main factors driving bird community assembly within the three major rivers. Notably, for bird communities along different river reaches, the integration of functional and phylogenetic diversity prevented the mis-classification of over-dispersion or clustering in community structure caused by traits with weak phylogenetic signals, or the observation of traits unrelated to community assembly patterns. This empirical study demonstrates the importance of integrating functional and phylogenetic diversity, which not only contributes to gaining an understanding of the mechanisms underlying the development of community assemblies but also facilitates a determination of the extents to which function and phylogeny contribute to shaping the patterns of communities.

The relative influence of climate extremes and species richness on the temporal variability of bird communities.

Understanding the relationship between biodiversity and ecological stability is increasingly urgent as rapid species extinction continues. Though evidence of positive diversity-stability relationships is accumulating, empirical results are inconsistent, and effect sizes tend to be small, raising questions about relative contributions of intrinsic (i.e., species composition/interactions) and extrinsic (i.e., environmental) drivers of stability. Community stability may be more strongly influenced by environmental conditions than by community diversity in some contexts, yet little is known about the comparative importance of diversity and climate means, extremes, and variability in regulating stability. We used a half-century of continental-scale bird data to quantify avian community temporal variability (a metric often used to approximate ecological stability) at 1379 sites and compared relative effects of climatic variables and species richness. We found that extreme heat and extremely low precipitation at decadal scales are associated with high bird community variability and these climate variables outperformed species richness in terms of variance explained and magnitude of effect. This provides empirical support for the theoretical concept that, at a continental, decadal scale, environmental conditions can play a larger role than intrinsic factors in determining community stability. Our findings also increase understanding of how climate extremes cause diverse ecological responses.

Bird Diversity of the Dry Chaco: Impacts of Land Use Change on Communities and Soundscapes

ABSTRACTAgricultural expansion has had negative impacts on biodiversity worldwide. Regions with high human pressure, such as the Dry Chaco in South America, require rapid studies to understand the environmental impacts and potential biodiversity loss. Ecoacoustics has been proposed as an efficient method for promoting rapid assessment of threatened regions. Using a unique field‐based bird community dataset, we evaluated the performance of two commonly used acoustic indices (acoustic diversity index and acoustic complexity index) on representing avian richness in continuous forest and forest corridors of the Paraguayan Dry Chaco. Our results from manual identification of recordings showed a higher species richness in continuous forest sites (40–61 species) than in forest corridors (22–36 species). In contrast, we found no difference in acoustic indices between sites in continuous forest or corridors. Contrary to our initial expectation, there was not a significant association between acoustic indices and bird species richness when considered across all sites. However, we found a partial and weak correlation between species richness and index values for forest corridors. We argue that habitat fragmentation and edge effects might have altered the soundscape of forest corridors, favouring bird activity rather than richness, which affects the acoustic indices response. Our study suggests that acoustic indices must be considered cautiously because other variables, besides species richness, are involved in soundscape characterisation (e.g., species vocal activity).