Structure Of Bird Assemblages Research Articles

Bird assemblage structure in the Desert Puna in areas with different disturbance activity of a subterranean herbivorous rodent

Bird assemblage structure in the Desert Puna in areas with different disturbance activity of a subterranean herbivorous rodent

Disentangling the drivers of urban bird diversity in the non-breeding season: A general synthesis.

Current knowledge about the impacts of urbanisation on bird assemblages is based on evidence from studies partly or wholly undertaken in the breeding season. In comparison, the non-breeding season remains little studied, despite the fact that winter conditions at higher latitudes are changing more rapidly than other seasons. During the non-breeding season, cities may attract or retain bird species because they offer milder conditions or better feeding opportunities than surrounding habitats. However, the range of climatic, ecological and anthropogenic mechanisms shaping different facets of urban bird diversity in the non-breeding season are poorly understood. We explored these mechanisms using structural equation modelling to assess how urbanisation affects the taxonomic, phylogenetic and functional diversity of avian assemblages sampled worldwide in the non-breeding season. We found that minimum temperature, elevation, urban area and city age played a critical role in determining taxonomic diversity while a range of factors-including productivity, precipitation, elevation, distance to coasts and rivers, socio-economic (as a proxy of human facilitation) and road density-each contributed to patterns of phylogenetic and functional diversity. The structure and function of urban bird assemblages appear to be predominantly shaped by temperature, productivity and city age, with effects of these factors differing across seasons. Our results underline the importance of considering multiple hypotheses, including seasonal effects, when evaluating the impacts of urbanisation on biodiversity.

Ecological structure of the avifauna composition as a basis for assessment of its heterogeneity and dynamics

The article describes the methodological approach and the results of classification of breeding bird species in Belarus by their preference for habitat type during the breeding season based on this approach. During the classification process, we took into account the preferences developed in the course of evolution, i. e. those that had been the most characteristic of the species before the domination of altered territories and the escalation of an urbanization rate, as well as before many species started living in urban environments on a large scale.In total, we defined six ornithofaunistic complexes (forest, arboreal-shrub, water-coastal, marsh, dry open spaces and synanthropic) that include all 223 bird species that have been observed breeding in Belarus since 2000. In most cases, the ornithofaunistic complexes were further divided into clusters that reflect a prominent ecological differentiation of species, although less drastic than a difference between the complexes themselves. In controversial or debatable cases, to justify attributing a species to a certain ornithofaunistic complex, we compared and analyzed all available data on the occurrence and breeding density of the species. Most breeding bird species belong to forest and water-coastal ornithofaunistic complexes (80 and 64 species, respectively), while only 12 species belong to the ornithofaunistic complex of dry open spaces. This classification proves to be a convenient tool to estimate the size and nature of the changes in the ecological structure of bird assemblages that have undergone some interference or transformations in time as well as to get comparable ecological characteristics of bird populations in different territories.

Contrasting impacts of non-native and threatened species on morphological, life history, and phylogenetic diversity in bird assemblages.

Human activities have altered the species composition of assemblages through introductions and extinctions, but it remains unclear how those changes can affect the different facets of biodiversity. Here we assessed the impact of changes in species composition on taxonomic, functional, and phylogenetic diversity across 281 bird assemblages worldwide. To provide a more nuanced understanding of functional diversity, we distinguished morphological from life-history traits. We showed that shifts in species composition could trigger a global decline in avian biodiversity due to the high number of potential extinctions. Moreover, these extinctions were not random but unique in terms of function and phylogeny at the regional level. Our findings demonstrated that non-native species cannot compensate for these losses, as they are both morphologically and phylogenetically close to the native fauna. In the context of the ongoing biodiversity crisis, such alterations in the functional and phylogenetic structure of bird assemblages could heighten ecosystem vulnerability.

Seasonal changes in the structure of bird assemblages in tide-dominated marine coastal wetlands of Chiloe Archipelago (Chilean Northern Patagonia, South America)

Seasonal changes in the structure of bird assemblages in tide-dominated marine coastal wetlands of Chiloe Archipelago (Chilean Northern Patagonia, South America)

Changes in bird assemblages following an outdoor music festival: A BACI (before-after-control-impact) monitoring from central Italy

An assessment of the short-term effects of an outdoor music festival (Jova Beach Party event; July 2019; central Italy) on bird assemblages has been carried out, adopting a BACI (Before-After-Control-Impact) survey design, and using the point counts method both in the impact site (Impact, I; where the concert was held) and in comparable Control site (C). In the I site, data have been stratified both for urban (U) and agro-mosaic (M) habitats. When comparing before and after the music event, in IU site, the species richness and the Hill diversity index decreased, differently from CU where species richness a species abundance increased. Diversity profiles highlighted the impoverishment of bird assemblages after the event, but only in the Impact urban habitats. After the musical event, individual rarefaction curves for richness were lower in IU after the concert, while, differently in CU curves are higher. These data suggest an impact in bird assemblages limited to the urban site, due to the stress mainly induced by high intensity noise pollution. Musical events may disrupt the structure of synanthropic bird assemblages, inducing a dispersal of individuals towards the surrounding landscape. Starling (Sturnus vulgaris) appeared a particularly sensitive bird. However, further efforts are necessary to study the effects of these events at species level.

The Importance of Wetlands for the Conservation of Birds in Tigray National Regional State (Northern Ethiopia)

Many birds use wetland habitats for all or part of their lives. This study was conducted to investigate the significance of wetlands and associated habitats for bird conservation in the central zone of Tigray, northern Ethiopia, from June 2022 to May 2023. The point count method was used to study the bird assemblage structure and diversity. The Shannon–Wiener diversity index and ANOVA were used to analyze the wetland bird community structure. A total of 4337 individual birds belonging to 120 species, 15 orders, and 41 families were recorded. Among the identified bird species, the Abyssinian catbird, white‐winged cliff chat, Abyssinian longclaw, wattled ibis, and black‐winged lovebird are endemic and near‐endemic species, which are found only in Ethiopia and Eritrea. The Passeriformes order had the greatest number of species (n = 68), followed by the Columbiformes order (n = 9). The​ Mai‐Shigurti Wetland had the greatest abundance of birds (N = 2472), while the Hatsebo Wetland had the least (N = 936). A high abundance of birds was recorded during the wet season (N = 2805), and a low abundance was recorded during the dry season (N = 1532). A significant difference in the abundance of bird species was observed among wetlands and seasons (p < 0.05). The highest species diversity (H′ = 4.13) was recorded in Mai‐Shigurti during the wet season, whereas the lowest was recorded in Hatsebo during the dry season (H′ = 3.2). The highest species evenness was recorded in Hatsebo (E = 0.82) during the dry season, and the lowest was recorded in Mai‐Shigurti (E = 0.72) during the wet season. The results show that wetlands support a high diversity of birds; however, they are highly threatened by anthropogenic threats, including solid waste disposal, erosion, agricultural expansion, human settlement, livestock overgrazing, military camping, and eucalyptus cultivation. Therefore, community‐based conservation initiatives should be implemented to mitigate these threats. Moreover, wetland management policies should be established to safeguard wetlands and their biological resources.

Taxonomic and functional structure of understorey bird assemblages on Amazonian seasonally flooded river islands

Abstract The seasonal inundation of the floodplains of the Amazonian rivers is a natural and strong environmental filter for biota. Its effects on the taxonomic and functional attributes of assemblages, however, remain poorly understood. We investigated the taxonomic and trait diversity of understorey bird assemblages on fluvial islands subject to dramatic seasonal flooding in the Amazon. Birds were captured using mist-nets on ten fluvial islands and at 17 sites in unflooded terra firme forests. We captured 1552 individuals of 116 bird species in 4144 net-hours. Average capture rates were similar between the forest types, but species diversity was higher in terra firme forests. The bird assemblages of the islands showed higher species dominance, with only three species accounting for 47% of the individuals captured. Functional space was occupied similarly in both bird assemblages, as indicated by functional dispersion indices (Fdis). In contrast, functional evenness (Feve) was lower in the river island assemblages indicating that the dominant species share similar traits. Functional divergence indices (Fdiv) showed substantial niche differentiation between the bird assemblages of the two forest types. Low inter-annual variability in avian taxonomic and trait diversity was observed in river islands, probably associated with the predictability of the flooding regime.

Trait‐environment associations diverge between native and alien breeding bird assemblages on the world's oceanic islands

AbstractAimTo investigate spatial variations in the ecological trait structure of breeding bird assemblages on oceanic islands. To test the hypothesis that native and naturalized alien bird species are filtered by different processes, leading to diverging associations between traits and insular environmental gradients.LocationOceanic islands worldwide.Time PeriodCurrent.Major Taxa StudiedTerrestrial breeding birds.MethodsWe assessed the composition of breeding terrestrial bird assemblages from the extent‐of‐occurrence maps of 3170 native and 169 naturalized alien species on 4660 oceanic islands. We quantified their ecological trait structures with respect to diet, mobility and body mass as the standardized distance between a mean pairwise trait distance index and its expectation from a null model. We used spatial generalized additive models to relate trait structures to proxies of environmental conditions and human impact on land, accounting for all species, native species only and alien species only.ResultsDiet and mobility traits tended to be more diverse than expected by a null model, while body mass tended towards clustering. Trait‐environment associations were idiosyncratic, but environmental variables tended to explain trait structures better than human impacts on habitats. Islands invaded by alien species had similar trait structures as noninvaded ones, although they hosted assemblages with more clustered body masses. However, trait‐environment relationships diverged when considering all islands and all species, invaded islands only or alien species only.Main ConclusionsDespite their ecosystem‐level influences, alien species have a limited effect on the global patterns of trait structures in the breeding bird assemblages of the world's islands, either because they account for a low proportion of species or because successful invaders and native species have similar trait suites. Trait‐environment associations suggest that filters related to the conditions of alien species' introductions explain their distributions in island assemblages better than the constraints associated with isolated environments.

Stochastic processes shape the functional and phylogenetic structure of bird assemblages at the mine area in southwest China.

Understanding the mechanisms of community assembly is a key question in ecology. Metal pollution may result in significant changes in bird community structure and diversity, with implications for ecosystem processes and function. However, the relative importance of these processes in shaping the bird community at the polluted area is still not clear. Here, we explored bird species richness, functional, and phylogenetic diversity, and the assembly processes of community at the mine region of southwest China. Our results showed that the 3 dimensions of diversity at the mine area were lower than that at the reference sites. In the community assembly, the result was 0 < NRI/ NFRI < 1.96, which indicated deterministic processes (environmental filtering) might drive community clustering. The results of the neutral community model, and normalized stochasticity ratio, showed the dominant role of stochastic processes in shaping the bird community assembly. We further quantified the community-level habitat niche breadth (Bcom), and we found that there was no difference in Bcom-value between the mine area and reference sites. This indicates that the bird communities at the mine area and 3 reference sites were not subjected to extreme environmental selection (same or different resource allocation) to form a highly specialized niche. These findings provide insights into the distribution patterns and dominant ecological processes of bird communities under metal exposure, and extend the knowledge in community assembly mechanisms of bird communities living in the mine area.

Structure of breeding bird assemblages in the city of Windhoek, Namibia

The line transect method was employed to count birds in four urbanized habitats in the city of Windhoek, Namibia. Most counts were conducted during July-October, in 2012-2014. Twelve transects with a total length of c. 86 km were located in places representing major urban habitats: residential areas (city centre, suburbs in lowland, suburbs in highland, and city periphery), sport fields, and a modern industry area. In total, 80 bird species (excluding Palearctic visitors) were recorded. For all species, we calculated linear population densities and dominance. Six species were classified as dominant: house sparrow, red-eyed bulbul, Southern masked weaver, laughing dove, wattled starling and white-backed mousebird. Their cumulative numerical abundance comprised 54.2 % of all the breeding species. The group of dominant species varied markedly among transects. Granivores were the most important feeding guild, comprising more than half of all birds in Windhoek. Frugivores (26 %) were more numerous than insectivores (19 %). Birds nesting in trees and/or in shrubs comprised two thirds of all birds. Surprisingly, few differences in the structure of feeding and nesting guilds were recorded among the four urban habitats. Windhoek avifauna is similar in dominance structure to avifauna in other southern African cities and towns, where sparrows, doves/pigeons, bulbuls and mousebirds dominate, and with granivores being the main feeding guild. Species richness declines and bird abundance increases along urban gradient (towards the city centre).

Understory bird assemblage in a riparian environment dominated by Cecropia membranacea (Urticaceae) in southwestern Amazonia

Studies on bird assemblage structure in pioneer environments allow us to understand the use of space, distribution patterns, ecosystem services, and population dynamics of these ephemeral habitats. However, studies on the bird community related to these types of habitats in the southwest of the Brazilian Amazon are rare. We compared the bird assemblage structure of an area dominated by embaúba-da-várzea (<em>Cecropia membranacea</em> Trécul) with the adjacent alluvial rainforest along the Chandless River, a right-margin tributary of the Purus River, in the southwest Brazilian Amazon. Birds were captured with mist nets and banded (with a metal ring) along trails in both habitats. The following environmental variables were measured: temperature, humidity, and canopy openness. Understory bird assemblage was similar in the two habitats, with no influence from the environmental variables sampled. Average similarity of understory species composition between the two habitats was 77.6%, <em>Pipra fasciicauda</em> being the species that most contributed to this similarity (10.76%). Despite their almost homogeneous canopy and inconspicuous understory composed of short life cycle plants, due to the impact of river dynamics, areas dominated by <em>C. membranacea</em> have an understory bird assemblage composition similar to that of the adjacent alluvial rainforest. Understory species move horizontally and easily between these two habitats. Habitats dominated by <em>C. membranacea</em> on the lower Chandless River, contrary to expected, harbor a rich bird fauna. Given its importance to biodiversity maintenance, the protection of this habitat is recommended, as well as the undertaking of further biological studies on this unique Amazonian ecosystem.

Bird Fauna Composition in a Protected Area in Southern Brazil.

The integrity of natural landscapes is affected by human actions, mainly by the intensification and expansion of agriculture. Factors such as fragment size and the structure of the environment can determine changes in the structure and composition of bird assemblages. In this study we evaluated the bird species composition in three structurally different forest environments, defined as the Core areas, Edge areas, and Buffer areas. The surveys were performed in the Natural Park of Sertão (NPS) and its surroundings in the southern limit of the Atlantic Forest, southern Brazil. To record species composition of birds, the point count method was used. The bird species were categorized according to feeding habits, habitat use, and sensitivity to forest fragmentation. A total of 131 species of birds distributed in 18 orders and 38 families were recorded. The species composition varied between the three areas and there was a significant difference in diversity between the Core and Edge areas and the Core and Buffer areas. Omnivorous species were found more in the Buffer areas than in the Core areas. Species that use the Broad habitat were more frequent in the Buffer and Edge areas than in the Core areas. Species that use the Forest habitat were found more in the Core areas than in the Buffer areas. Most recorded species (66%) have low sensitivity to forest fragmentation. The assemblage patterns found in this study, notably the differences among the three areas in diversity and species composition, can be explained by the ecological traits and the sensitivity levels of birds to forest fragmentation, which in turn seem to reflect different forest structures in the NPS and its surroundings. Although the Edge and Buffer areas have greater diversity, the Core areas showed great importance in maintaining species that are more sensitive to forest fragmentation. Even the largest fragments (such as the NPS), considering the regional context, may have bird species that are widely distributed and less sensitive to forest fragmentation. Forested habitat species may no longer occur or be restricted to the core area of the fragments. For conservation of bird fauna in the NPS, the maintenance of the core areas is essential, especially for those species that require a structurally preserved environment.

The Spatial and Typological Structure and Organization of Summer Bird Assemblages in Kyrgyzstan

The Spatial and Typological Structure and Organization of Summer Bird Assemblages in Kyrgyzstan

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

&#x0D; &#x0D; &#x0D; 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.&#x0D; &#x0D; &#x0D;

Bird species co‐occurrence patterns in an alpine environment supports the stress‐gradient hypothesis

Understanding the relative contribution of different biotic interactions in shaping species assemblages constitutes a major goal in community ecology, and consequently, multiple methods aimed at inferring the nature of these associations have emerged during the last decade. In this framework, the stress‐gradient hypothesis (SGH) predicts that prevalent biotic interactions shift from competition to facilitation as abiotic stress increases (and productivity decreases). This hypothesis originally raised by plant ecologists has been barely applied to faunal communities. Here, we take advantage of 20 years of abundance data to investigate pairwise patterns in species co‐occurrence in alpine bird communities inhabiting two contrasting habitat types: forests (high productivity) and mountain grasslands (low productivity). We also integrate functional data with presence–absence and quantitative matrices in order to detect the signature of processes driving community assembly and test for limiting similarity. We employ a null model approach, probabilistic pairwise association tests and joint species distribution models; all methods revealed a higher frequency of positive interactions in mountain grasslands in agreement with SGH predictions. Both the frequency of positive and negative interactions remained moderately stable over the study period in both habitat types. There was no significant relationship between the degree of co‐occurrence of species pairs and their functional distance in either habitat. However, when we only considered those combinations of species whose co‐occurrence patterns deviated from that expected at random, we found that co‐existing species are functionally more similar than those pairs that show segregated patterns in the forest assemblages. Such a relationship may arise via selective social information use and other processes, including microhabitat preferences. Overall, our findings suggest that interspecific competition does not constitute a major force driving the structure of bird assemblages in this mountain region. This work also shows that association analyses should not be underestimated as they can provide clues to the mechanisms responsible for community structure.

Synergistic effects of habitat configuration and land-use intensity shape the structure of bird assemblages in human-modified landscapes across three major neotropical biomes

Maximizing biodiversity persistence in heterogeneous human-modified landscapes is hindered by the complex interactions between habitat quality and configuration of native and non-native habitats. Here we examined these complex interactions considering avian diversity across 26 sampling sites, each of which comprised of three sampling points located across a gradient of disturbance: core native habitat fragment, fragment edge, and non-native adjacent matrix. The 78 sampling points were further nested within three neotropical biomes—Amazonia, Cerrado and Pantanal—in central-western Brazil. Matrix type consisted of cattle pastures in the Amazon and teak plantations in the Pantanal and Cerrado. We considered the interactive effects of (1) disturbance-context: fragment core, edge and adjacent matrix, (2) matrix type: tree plantation or cattle pastures, both subject to varying land-use intensity, and (3) native habitat configuration (fragment size, shape and isolation) on bird species richness, abundance and composition. Based on point-count surveys, we recorded 210 bird species. Bird species richness and abundance declined across the disturbance gradient, while genus composition only differed within the adjacent matrix, particularly cattle-pastures. The effect of native habitat area was positive but only detected at fragment edges. Overall bird diversity increased at sites characterized by higher availability of either relict trees within pasture landscapes or old-growth trees within teak plantation landscapes. The core of native fragments played a primary role in ensuring the persistence of bird diversity, regardless of fragment size. In contrast to pastures, tree plantations likely harbour a higher proportion of forest-dependent species while bird diversity can be further enhanced by reduced management intensity in both matrix types. Strategies to maximize avian persistence should not only include retaining native habitats, but also maximizing the size of core native habitats. Likewise, more structurally complex matrix types should be encouraged while maintaining low levels of land-use intensity.

Effects of low-impact logging on understory birds in the Brazilian Amazon

Tropical forests have a great potential for the exploitation of natural resources. Among the economic activities that depend on forest resources, timber production is the most important one. Nevertheless, these activities may negatively affect wildlife, the availability of natural resources, and ecosystem process. Here we analysed the effects of low-impact logging on understory bird species richness, number of individuals captured, species composition, and assemblage structure in central Brazilian Amazon. We compared logged and unlogged areas over a period of three years (from August 2014 to May 2017). We captured a total of 180 birds and 42 species (20 families) in the logged area and 226 birds and 49 species (20 families) in the unlogged area. Bird assemblage structure in the logged area changed more intensely over the three years of study and became more similar to the assemblage found in the unlogged area. The degree of similarity (Jaccard’s index) in species composition between logged and unlogged areas increased from 18% in the third year to 39% in the fifth year after logging. The results suggest that the minor effects of low-impact logging were reduced a few years after the disturbance, probably due to ecological succession. The proximity of logged and unlogged areas and the reduced impact in the study site may facilitate the recovery of the bird assemblage after the disturbance.

Life in the extreme environment: Structure and species richness of bird assemblages on Yuzhny Island of Novaya Zemlya, Russia

Birds play a vital role in arctic environments, being multi-functional ecosystem engineers, but these animals are heavily impacted by recent climate warming. Bird assemblages on the Arctic Ocean archipelagoes are poorly known, because many such areas are hardly accessible to scientists. Novaya Zemlya, one of the most enigmatic places in the World, was a closed military area from the late 1940s. This gigantic mountainous archipelago can be considered a terra incognita by means of modern faunal, taxonomic, and ecological research. In the present study, we provide the first qualitative data on bird assemblages of the Yuzhny Island of Novaya Zemlya, estimate the diversity of bird species through a range of habitats, and underscore environmental factors determining the spatial distribution of avifauna in the arctic tundra biome. In terrestrial habitats, Tundra Bean Goose (Anser fabalis rossicus), Barnacle Goose (Branta leucopsis) and Snow Bunting (Plectrophenax nivalis) were the most abundant species. In freshwater and coastal marine habitats, both these Arctic-breeding goose taxa, and Black-legged Kittiwake (Rissa tridactyla), Common Eider (Somateria mollissima) and Thick-billed Murre (Uria lomvia) were the dominant species. The most species-rich bird assemblages (11-15 species) were associated with willow tundra, freshwater lakes, and coastal sea habitats, while only a few species were recorded in dry rocky habitats, open sea environments, and littoral areas of lakes and the sea. Mountain rocky heathlands covering most of the area of Yuzhny Island were scarcely populated by birds, with only a few species recorded frequently there, such as the Rough-legged Buzzard (Buteo lagopus) and Snow Bunting. Our findings highlight that the bird assemblages on Novaya Zemlya share low species richness and that these assemblages contain a large proportion of sea and shore bird species even in terrestrial habitats. Among the terrestrial birds, only four cold-tolerant, common species successfully colonize these extreme environments during the short summer season.

Species Abundance and Body Size Relationship of Bird Assemblages at Selected Sites in Western Sarawak

The Energy Equivalence Rule (EER) is an unresolved issue in ecology. This rule states that the amount of energy used for each species in a population is independent of its body size. A study on the relationship between abundance and body size of bird assemblages was conducted in Western Sarawak. Abundance data of bird assemblages from seven selected sites in Western Sarawak were used to produce a regression line of log absolute species abundance versus log average body mass. Data from all selected sites were combined to represent bird assemblages in Western Sarawak and the slope produced was -0.216. The slopes obtained for each site were 0.808, -0.080, -0.258, -0.067, -0.161, -0.072 and -0.237, respectively. Statistical analysis shows that the slope of combined data did not differ significantly from -0.75, as expected under the EER. Thus, this study shows that the EER can be applied as a general rule of community structure of bird assemblages in Western Sarawak.