Bird Assemblages Research Articles

Bird Communities in Coastal Areas. Effects of Anthropogenic Influences and Distance From the Coast

Urbanization effects have been studied all over the world, documenting impact in species richness, abundances and changes in species communities. Birds have been broadly used as study models. In general, urbanization affects birds, reducing species richness, especially in the urban core, and increasing species richness in areas with intermediate levels of disturbance, such as suburbs. Urbanization also changes species assemblages depending on urban characteristics and resources available, creating habitats for different species. Even when more than half of the cities in the world are on the coast, the effects of urbanization on habitat use of terrestrial and marine birds in coastal urban environments has received little attention. We hypothesized that coastal cities would present different bird diversity in modified marine areas and modified inland areas as terrestrial and marine ecosystems coexist. We predict that modified marine areas will have higher species richness than modified inland areas and natural marine areas. For bird assemblages, we expect to find similar species compositions between sites with similar habitat characteristics more than closeness. We compare habitat use of marine and terrestrial avifauna in the human-modified coastal city of Valparaiso, Chile, characterized by a range of urban developments within city boundaries. We specifically compare corrected bird abundance in six different possible habitats for birds, according to distance to the coast, and human influence. Bird counts (50 m fixed radius) were conducted in winter and spring of 2019. Bird species richness and abundances, corrected by the probability of detection, were estimated. Additionally, species composition and occupancy of bird species in those habitats were calculated. Results show that coastal urban cities can provide different habitats for bird species. Modified inland habitats differ from semi-natural inland habitats and from the modified beaches in species richness and species composition. Environmental heterogeneity in coastal cities seems to allow the coexistence of marine and terrestrial bird species, showing differences in species richness and bird assemblages for marine-inland environments and natural- modified habitats. Results highlight the need to consider these factors for urban planning in order to conserve bird diversity in coastal urban areas.

Frugivore distributions are associated with plant dispersal syndrome diversity in the Caribbean archipelagos

AbstractAimMany plants rely on interactions with frugivores for dispersal, suggesting that animal communities may affect plant occupancy and diversity. However, the contribution of these interaction‐led biotic variables on plant diversity is poorly understood, especially in archipelagic hotspots such as the Caribbean. In island ecosystems, biogeographic theories suggest that island configurations drive colonization‐extinction dynamics, while macroecology argues for the importance of climatic drivers of biodiversity. Within this context, we examine how frugivore‐driven biotic factors are associated with fruiting plant species richness in relation to abiotic (climatic and geologic) and island configuration characteristics.LocationCaribbean archipelagos.MethodsWe compiled a review of the diversity and distributions of 6039 plants and 326 vertebrate frugivores across 105 islands within the Caribbean. We then identified characteristics related to plant‐frugivore interactions and assigned each species as having either abiotic (wind, water, etc.) or zoochoric (frugivory‐dependent) dispersal syndromes. We related plant richness and dispersal syndromes to the regional diversity and characteristics of frugivorous animals, abiotic environments and island configuration characteristics through stepwise multivariate regression with generalized linear models and model selection.ResultsWe found that 44.6% of Caribbean plants are dispersed through frugivory (endozoochory). Frugivore‐related characteristics, namely accumulated body mass of island bird assemblages, were the best predictors of the diversity of seed dispersal syndromes. To a lesser degree, reptile richness and soil variety were also considered important predictors for zoochoric plant distribution, while island areas affected abiotically‐dispersed plants.Main conclusionWe found that biotic characteristics of frugivore communities are important predictors of plant diversity in the Caribbean archipelagos. However, this may also be influenced by climate and colonization history. Given the importance of biotic metrics in explaining plant diversity, we suggest that fruit‐frugivore interactions are important components of island biogeography and that frugivorous communities should be accounted for plant biodiversity predictions and forecast models.

The specter of empty countrysides and wetlands—Impact of hunting take on birds in Indo‐Burma

AbstractHunting for the wild meat trade, medicines and other human uses has decimated Indo‐Burma's vertebrate biota and has led to widespread defaunation. Yet, there is surprisingly little data on how hunting impacts wild bird assemblages in different landscapes here. Based on concurrent snapshot surveys of bird hunting, food markets and hunting attitudes across six Indo‐Burma countries, we found that hunting threatens species not only in forested landscapes but also wetlands and farmlands such as orchards and paddy fields—ecosystems overlooked by past studies, with at least 47 species associated with wetlands and agricultural lands identified from market surveys across the region. High rates of mortality are suffered when hunting tools such as nets are used to exclude perceived bird pests in both aquaculture and agricultural landscapes, with over 300 individual carcasses of at least 29 identifiable species detected in one aquaculture landscape sampled in Thailand. We warn that the potentially unsustainable trapping of species for consumption and trade in Indo‐Burma, coupled with high incidental mortalities, could decimate the populations of erstwhile common and/or legally unprotected species. There is an urgent need for stronger regulatory oversight on the hunting take of wild birds and the use of hunting tools such as nets. Alongside this, conservation practitioners need to better engage with rural communities to address unsustainable hunting practices, especially outside of protected areas.

Long-term dynamic of nestedness in bird assemblages inhabiting fragmented landscapes

ContextNestedness is a common pattern of species assemblages in fragmented landscapes. The spatial pattern and ecological drivers of nested communities have been widely explored, but few studies investigated their long-term variability.ObjectivesTo investigate the variability of nestedness and species-specific fragment occupancy of forest birds in a fragmented landscape affected by environmental changes over 16 years.MethodsData were obtained from the Monitoring Program of Breeding Birds in Lombardy (northern Italy). For two study periods (1997–2001, 2013–2017), we tested for overall nestedness and for sites and species nestedness independently using the NODF metric. We tested for nestedness drivers (variable selection on multiple linear regression models) and evaluated the effect of species ecological traits on fragment occupancy changes (variable selection on multiple linear regression model).ResultsThe community showed a significant nestedness driven by both selective extinction and selective colonization in both study periods. Sites nestedness was significant in the second study period only. Over 16 years the effect of distance from source areas was completely lost and only local isolation conditions drove selective colonization in the second study period. Between the two study periods, we discovered a general occupancy decrease of interior species and a significant occupancy increase of generalist species characterized by large size and large minimum area requirement.ConclusionsNestedness drivers of the investigated community significantly varied over time probably because of both environmental and demographic changes. Long-term studies are crucial to explore spatial pattern changes and to address management strategies for species conservation in fragmented landscapes.

Assessing taxonomic and functional change in British breeding bird assemblages over time

AbstractAimThe aim was to identify the primary drivers of compositional change in breeding bird assemblages over a 40‐year period.LocationBritain.Time periodFrom 1970 to 2010.Major taxa studiedBirds.MethodsUsing morphological trait measurements and a dataset of presence–absence data for British breeding birds surveyed in 10 km × 10 km hectads during two time periods, we calculated temporal taxonomic and functional beta diversity for each hectad alongside the change in species richness, mean nearest taxon distance (MNTD) and mean pairwise distance (MPD). We also estimated potential drivers of beta diversity, including climatic and land‐use and land‐cover (LULC) change variables, elevation and assemblage species richness in 1970 (1970rich). We used random forest regressions to test which variables best explained compositional change in the assemblages. We also assessed spatial taxonomic and functional change by analysing multiple‐site beta diversity and pairwise dissimilarities between time periods.ResultsInitial (1970) species richness was the most important predictor (highest importance score) across all models, with areas characterized by higher initial richness experiencing less assemblage change overall. The coordinates included to capture spatial autocorrelation in the data were also important predictors of change. Most climate and LULC variables had relatively low explanatory power; elevation and average temperature were the most influential. All metrics increased slightly with increasing elevation, except for species richness change and MPD, which decreased.Main conclusionsThe composition of British breeding bird assemblages changed substantially between 1970 and 2010. Spatial heterogeneity increased, both taxonomically and functionally. We show evidence that hectads with larger assemblages have been buffered from temporal diversity change and that those at higher elevations changed more in composition than those at lower elevations. Overall, coarse‐resolution climate and LULC explained only small to moderate amounts of variation, suggesting that stochastic assembly change or finer‐scale drivers might be drivers of temporal changes in assemblage composition.

Impact of Oyster (Crassostrea virginica) Reef Restoration on Benthic Invertebrates and Coastal Birds in a Subtropical Estuary

In order to mitigate the degradation of eastern oyster (Crassostrea virginica) reefs in Mosquito Lagoon (ML) along the east coast of central Florida, oyster reef restoration efforts have been in place for over 14 years. These restored reefs are successful in terms of universal oyster metrics (i.e., density, shell height, reef height) and are similar to natural reefs. However, little is known about the impact of this restoration on bird populations. ML provides a habitat for many bird species, including several listed as “threatened” by the Florida Fish and Wildlife Conservation Commission. Many of these birds rely on oyster reefs for foraging and loafing habitats. As benthic invertebrates serve as an important food source for coastal birds, we monitored the abundances and diversity of these organisms on live, restored, and dead reefs. We collected sediment samples from the reef sites pre-restoration, and one month, six months, one year, two years, and three years post-restoration. We counted benthic invertebrates present in the sediment samples, and sorted them by taxa (polychaetes, amphipods, isopods, gastropods, bivalves, decapods). Benthic invertebrate abundances on restored reefs became similar to live reefs over time (species composition, density), indicating that the prey base on restored reefs was similar to that of live reefs within 6 months. A second objective of this study was to determine if restored oyster reefs reach the same abundances, foraging behaviors, and diversity of bird species on natural, live reefs. We conducted monthly bird surveys to assess bird utilization of live, restored, and dead reefs. After three years, the abundances, behaviors, and assemblages of birds on restored reefs were similar to live reefs.

Post-monsoon bird assemblages in rural and riverine environments of Northern Howrah, West Bengal, India: A spatio-temporal approach

The primary goal of this study was to evaluate avian assemblages in four different land types (Wetland Associated Bamboo Forest, Agricultural Land, Wetland Associated Agricultural Land and Riverside Agricultural Land) located in a flood prone area of South Bengal during the post monsoon months of 2020. Surveys were conducted for 48 days in a land type and time dependent manner to explore the changes in abundance, dominance, evenness and species richness. A total of 18654 observations belonging to 16 orders, 44 families, 70 genera and 81 species were recorded. Despite having lowest total count and third species rich area, Bamboo Forest emerged as the most diverse area with the highest Shannon index (3.37), Evenness index (0.4616) and lowest dominance index (0.06108). Bamboo forests exhibited the maximum values of Simpson 1-D (0.9389), Brillouin index (3.312), Menhinick Index (1.261), Equitability (0.8134) and alpha diversity (Fisher’s alpha 11.74). Having maximum number of species occurrence (69), Riverside agricultural land was found to be the least diverse land type (Shannon index 2.847) showing highest value of dominance (0.1203). December attracted the most diverse (Shannon index 3.474) bird community and October showed the lowest value of Shannon index (2.919) with maximum value of dominance (0.123). We conclude that protection of natural habitats like bamboo forests, wetland and tree cover in small villages and proper management of agricultural lands is necessary for promoting species diversity and evenness in a rural environment.

Does spring bring colors? Seasonal bird plumage color variation along urban-rural gradients

Urbanization alters the landscape through the replacement of natural vegetation by impervious surfaces, probably inducing changes in interspecific bird color diversity and composition. However, the seasonal changes of bird color diversity and composition along urban-rural gradients have not been analyzed yet. The objective of this study was to analyze the seasonal variation of bird color diversity and composition of bird assemblages along urban-rural gradients of three cities in central Argentina. Bird surveys were made in urban, suburban and rural areas during the breeding and non-breeding seasons. Color description was obtained from the literature. Color diversity and the seasonal color dissimilarity were calculated using the mean pairwise distance functional index. Null models that control for species richness were used to estimate standardized effect sizes (SES). Color diversity increased during the breeding season. However, the SES of color diversity did not change between seasons. Color diversity and the SES of color diversity were higher in rural areas than in urban habitats. The color seasonal dissimilarity was the lowest in urban habitats. City size was negatively related to the color seasonal dissimilarity in urban and suburban habitats. Species with brown, black and dimorphic plumages showed seasonal changes in their abundances in rural habitats, whereas plumage colors in urban habitats remained stable between seasons. The results showed that bird color diversity increase during the breeding season, but this increase is related to the arrival of more species during the breeding season to rural areas. Urban areas showed a seasonal homogenization of bird colors.

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The cover image relates to the Research Article http://doi.org/10.1111/ddi.13458 “Glacier influence on bird assem blages in habitat islands of the high Bolivian Andes” by Cardenas et al. The uncommon and near-threatened diademed sandpiper-plover (Phegornis mitchellii) in the high Bolivan Andes. Photo credit: O. Dangles

Responses of birds and mammals to long-established wind farms in India

Wind turbines have been recognised as an alternative and clean-energy source with a low environmental impact. The selection of sites for wind-farm often creates serious conservation concerns on biodiversity. Wind turbines have become a serious threat to migratory birds as they collide with the turbine blades in some regions across the globe, while the impact on terrestrial mammals is relatively less explored. In this context, we assessed the responses of birds and mammals to the wind turbines in central Karnataka, India from January 2016 to May 2018 using carcass searches to quantify animal collisions (i.e., birds and bats), fixed radius point count for bird population parameters, and an occupancy framework for assessing the factor that determines the spatial occurrence of terrestrial mammals. The mean annual animal fatality rate per wind turbine was 0.26/year. Species richness, abundance, and unique species of birds were relatively higher in control sites over wind turbine sites. Species and functional compositions of birds in control sites were different from wind turbine sites, explaining the varied patterns of bird assemblages of different feeding guilds. Blackbuck, Chinkara, Golden Jackal, and Jungle Cat were less likely to occupy sites with a high number of wind turbines. The study indicates that certain bird and mammal species avoided wind turbine-dominated sites, affecting their distribution pattern. This is of concern to the management of the forested areas with wind turbines. We raised conservation issues and mitigating measures to overcome the negative effects of wind turbines on animals.

Projected changes in bird assemblages due to climate change in a Canadian system of protected areas.

National parks often serve as a cornerstone for a country’s species and ecosystem conservation efforts. However, despite the protection these sites afford, climate change is expected to drive a substantial change in their bird assemblages. We used species distribution models to predict the change in environmental suitability (i.e., how well environmental conditions explain the presence of a species) of 49 Canadian national parks during summer and winter for 434 bird species under a 2°C warming scenario, anticipated to occur in Canada around the mid-21st century. We compared these to existing species distributions in the 2010s, and classified suitability projections for each species at each park as potential extirpation, worsening, stable, improving, or potential colonisation. Across all parks, and both seasons, 70% of the projections indicate change, including a 25% turnover in summer assemblages and 30% turnover in winter assemblages. The majority of parks are projected to have increases in species richness and functional traits in winter, compared to a mix of increases and decreases in both in summer. However, some changes are expected to vary by region, such as Arctic region parks being likely to experience the most potential colonisation, while some of the Mixedwood Plains and Atlantic Maritime region parks may experience the greatest turnover and potential extirpation in summer if management actions are not taken to mitigate some of these losses. Although uncertainty exists around the precise rate and impacts of climate change, our results indicate that conservation practices that assume stationarity of environmental conditions will become untenable. We propose general guidance to help managers adapt their conservation actions to consider the potentially substantive changes in bird assemblages that are projected, including managing for persistence and change.

Functional Responses of Bird Assemblages to Land-Use Change in the Colombian Llanos Region

Land-use change in the Colombian Llanos due to agro-industrial expansion affects biodiversity. This change alters species occurrence probability, consequently impacting species’ composition. For some species, the occurence probability increases with land-use changes, while it stays unchanged or decreases for others. This interspecific variation in the response to land-use change may be mediated by functional traits, among other factors. We investigated response functional traits to land-use changes and their influence on the occurrence probability of bird species in the Colombian Orinoquia region. We compiled data for 13 morphological and life-history traits of 364 species recorded in forests, savannas, rice fields, palm oil crops, and livestock pastures in the piedmont and flooded savanna landscapes. We used a novel framework to identify response functional traits (i.e., traits with a significant effect on occurrence probability) through multiple statistical tests. We used random forest models to identify response functional traits to land-use change for pairwise comparisons of natural vs. agricultural land use types. For the functional traits, we estimated the influence of their states as trait attributes on species’ responses to land-use changes. We identified functional groups based on hierarchical clustering analysis. Functional groups corresponded to different levels of response, that is, different changes in probability occurrence. Land-use changes altered the multidimensional space of bird traits (i.e., functional diversity), implying modifications in species' composition, functional redundancy, and functional group turnover. Functional traits were similar for random forest classifications of the same natural cover but differed among landscapes. In the piedmont forests, social behavior—migratory status—was a functional trait combination common to all classifications, while foraging behavior-nest location trait combination was common to all forests scenarios in flooded savannas landscape classifications. Migratory status was a functional trait for all savanna classifications. Functional groups described the impacts of land-use changes on bird assemblages. Identification and characterization of these groups using trait attributes can help predict species' responses to land-use changes and guide conservation efforts toward groups with decreased occurrence probability, including recommendations for agricultural practices that can reduce impacts on the Orinoquia biodiversity.

Taxonomic, Phylogenetic and Functional Diversity of Bird Assemblages in Urban Green Spaces: Null Model Analyses, Temporal Variation and Ecological Drivers

Urban expansion is a pervasive driver of biodiversity loss. To understand the effects of urbanization on diversity, we investigated the response of bird taxonomic, phylogenetic, and functional diversity to urban green spaces’ characteristics in thirty-one green spaces of Mexico City. Selected sites encompassed variation of environmental factors along a transformation gradient, from natural protected areas to landscaped parks. Bird observations were conducted during winter (non-breeding season), spring (dry breeding season), and summer (wet breeding season). We used multi-model inference to assess the relationship of green space area, shape, isolation, tree richness, habitat diversity, and vegetation cover with species richness, Faith’s phylogenetic diversity, and functional richness. We calculated standardized effect sizes from null models to assess phylogenetic and functional structure. We registered 91 species belonging to 28 families across all sites and seasons. The number of detected species was largest in winter and decreased toward the dry breeding season, and then toward the wet breeding season. We found a moderate to strong positive relationship of species richness with phylogenetic diversity and functional richness. Overall, phylogenetic and functional structure of bird communities in green spaces was neither clustered nor over-dispersed. However, few cases of functional clustering, phylogenetic clustering, or both were observed, and they corresponded to natural protected areas. Results showed a predominant role of green space area in determining community diversity and phylogenetic structure while it did not influence functional structure. Contrary to our predictions, habitat diversity had a negative effect on species richness and phylogenetic diversity and this effect was detected only during the wet breeding season, whereas isolation showed a positive relationship with phylogenetic and functional structure, during the wet breeding season and winter, respectively. This study emphasizes the use of complementary measures of diversity together with the comparison between observed and expected values to get a better insight into the mechanisms by which green spaces’ characteristics affect bird diversity across the seasons.

Connecting Amazonian historical biogeography and local assemblages of understorey birds: Recurrent guild proportionality within areas of endemism

AbstractAimCurrent diversity patterns in local communities result from historical and contemporary events that operate at distinct spatial and temporal scales. However, the contribution of local and large‐scale processes in structuring species diversity remain a contentious topic in ecology. We investigated diversity patterns (species richness, composition and number of captures) of understorey bird assemblages in Amazonian unflooded (terra firme) forests. We sought to understand whether understorey bird assemblages in distinct areas of endemism show distinct patterns of diversity, and whether species replacements among areas of endemism occur while the proportion of species within guilds remains stable.LocationAmazonia.TaxonUnderstorey birds.MethodsTo investigate diversity patterns, we compiled studies that mist‐netted birds at 11 regions across seven Amazonian areas of endemism. We used coverage‐based rarefaction curves, non‐metric multidimensional scaling (NMDS) and created a heatmap based on the proportion of captures in each area of endemism to access patterns of richness, composition and captures of understorey birds, respectively. The relative variance (RVgp index) was calculated to investigate the existence of guild proportionality within each area of endemism.ResultsBird assemblages diverged across the seven areas of endemism, in terms of species richness, composition and captures. However, the proportion of species and individuals within guilds was similar among areas of endemism, indicating that species replacements across areas of endemism occur while maintaining the same ecological functions. Guild proportionality suggests that interspecific competition and resource availability are more important than environmental heterogeneity in structuring understorey bird assemblages.Main conclusionsThe similar proportion of species within guilds suggest that interspecific competition and resource availability are more important than environmental heterogeneity in structuring local assemblages, possibly via a process of limiting similarity in morphological and functional traits. The observed congruent structure in understorey bird assemblages across areas of endemism shows that coupled historical and ecological processes, operating at local to large scales, have led to current patterns of diversity and composition in Amazonian bird communities.

Unburnt patches maintain bird abundance and species richness following large wildfires in an Australian semiarid woodland ecosystem

Large wildfires can cause widespread disruption to ecosystems and animal populations, but patches left unburnt within fire scars may play a key role in the persistence and post-fire recovery of communities, which may depend on habitat characteristics, patch size, or spatial configuration. To test this, we made use of a natural experiment in which a semi-arid landscape was burnt twice in the space of eight years. We surveyed bird assemblages at 130 sites, and tested the relative importance of time since fire, habitat features and landscape configuration of unburnt patches for post-fire species abundance, species richness and phylogenetic diversity. In the first three years after fire, abundance of 4/18 bird species were higher in unburnt patches than the surrounding burnt matrix, and after 8–10 years abundance of three species was still higher in unburnt patches. Short-term post-fire variation in species richness was associated with habitat differences between burnt and unburnt areas, but not with habitat differences among unburnt areas, nor with patch size or spatial configuration. Our results suggest that even small or isolated unburnt patches are important in maintaining bird abundance and species richness, and facilitating recovery of animal populations across large fire scars, especially in the first three years after a major fire event.

Seasonal bird assemblages in Dehesas (substeppic prairies with Quercus suber) of North-Western Sardinia (Italy): A poorly studied landscape of high eco-biogeographic interest

Dehesas (i.e., substeppic prairies with Quercus suber) represent a poorly studied Mediterranean habitat type of high eco-biogeographic interest. Here, we applied a point-transect method along a yearly cycle (from spring to autumn), to focus on seasonal differences in bird assemblages inhabiting a Dehesas landscape in north-western Sardinia (Italy). We confirmed the presence of Mediterranean species with restricted ranges (e.g. Sturnus unicolor, Sylvia sarda). At the community level, seasonal patterns show significant differences among mean abundance, with a maximum in autumn and a minimum in summer. The highest values in autumn may be explained by the aggregations of wintering small passerines. Considering the univariate metrics of diversity, the number of species significantly differs among seasons, with the richest community in spring. Shannon-Wiener diversity and Margalef (normalized richness) were higher in spring and summer compared to autumn. Habitat heterogeneity of these landscape mosaics, driven by historical agro-pastoral practices (fires and pastures), together with the presence of patchy 'key structures', positively affects bird species richness and abundance, improving, respectively, the number of niches and resources. More resource effort should be devoted to study these habitat types recently interested in an increased anthropogenic pressure (urban sprawl and road infrastructures, location of wind power plants, etc.).&nbsp

Urban landscapes are richer in bird species when compared to farming lands: evidence from Morocco (Northwest Africa)

Urban expansion leads to modifications of habitat features, organization, and resources. Bird assemblages are known to respond by escaping destructive changes and adapting to sustainable ones. In this study, we investigated for the first time the avian diversity and its variation following the rural-urban gradient in Beni Mellal (Morocco) from 2018 to 2021. We used the line-transect method and multivariate analysis to demonstrate the selection of breeding habitats. Our result revealed a total of 84 species divided into resident breeders (64.28%), passage migrants (17.85%), breeding migrants (26.19%), winter visitors (32.18%) and accidental visitors (1.19%). Two globally vulnerable species counting the European Turtle Dove Streptopelia turtur and the European Goldfinch Carduelis carduelis were recorded. Breeding populations were concentrated in green spaces (9 species) located in the urban zone, compared with farmlands (7 species), peri-urban (3 species), and rural areas (3 species). Therefore, these results reverse the hypothesis that rural and farming lands are more species-rich because of a higher population size. This is due to the abundance of breeding and foraging resources in urban green spaces compared to arid lands surrounding cities in this North African area. Furthermore, our study provides a new opportunity for comparative studies of avian diversity in Morocco and Northwest Africa.

Avian community changes following drought-induced canopy collapse in a Mediterranean-type forest

Context Extreme drought can result in the widespread die-off of forests and dramatically altered ecosystem structure. Such changes are likly to influence fauna using resouces within these forests. Aims Following a record hot and dry year/summer in 2010/11, large-scale canopy collapse occurred within a Mediterranean-type mixed jarrah (Eucalyptus marginata)–marri (Corymbia calophylla) forest in south-west Western Australia. We investigated the effects of this collapse on bird assemblages in 2016, 5 years after the initial collapse. Methods We carried out bird surveys using a standardised search method for five paired drought-affected and adjacent healthy forest plots. Key results A total of 3042 records of 51 bird species were observed across all surveys. Overall, the pooled (mean ± s.d.) reporting rates for drought-affected plots (13.84 ± 0.60 individuals/survey) were significantly less than the reporting rates for healthy plots (34.44 ± 1.03 individuals/survey) (PERMANOVA: F1 = 54.94, R2 = 0.31, P = 0.001). Species diversity was also higher in healthy plots (t26 = 11.21, P < 0.001). Foliage-searching birds were the most abundant guild across all plots and were reported less often in drought-affected plots (t6 = 2.70, P < 0.04). Conclusions Drought-affected jarrah forest plots exhibited significant differences in bird assemblages compared to healthy plots. Overall, the drought-affected forest provides a less favourable habitat for birds compared to healthy forest. Implications With marked variability and extreme climate events predicted for the future, understanding the impacts of such changes will contribute to how we manage forest ecosystems.

Species diversity and nestedness of bird assemblages in the forest fragments of Haikou and Sanya cities

Species diversity and nestedness of bird assemblages in the forest fragments of Haikou and Sanya cities

Avian Assemblages in Forest Fragments do not Sum to the Expected Regional Community in the Brazilian Atlantic Forest.

While bird diversity in the Atlantic Forest can be considered well-known, how the communities have been affected by deforestation and habitat fragmentation is not. We studied birds in 10 forest fragments of distinct sizes (all originally within the Atlantic Forest) in southern Bahia. In 5,391 bird encounters, we found 251 species, with 46 endemics and eight considered globally vulnerable or endangered. We also compiled a list of the 380 species that should comprise the expected regional assemblage, and found that only 66% of these species were present in all the fragments combined. Only 9% of all observed species were found in all fragments. The largest fragment (700 ha) had the greatest number of endemic species (40), and seven threatened species. All fragments had some conservation-important species (some were found in one or a few fragments), but no fragment included them all. Fragments shared 10% of endemic species, but overall, the contingent of endemics was unique in each fragment. Finally, most functional traits of bird assemblages decreased with increasing fragment size. Neither species richness nor similarity correlated with fragment size or distance between fragments, and unknown, non-random factors probably influence the likelihood of species survival in each fragment. Thus, to ensure the persistence of threatened species, as well as maintain the most common species, conservation management decisions should include all fragments together because no single fragment is most representative of the local community.