Bird Community Composition, Migration, and Environmental Factors Jointly Influence the Global Distribution of Avian Haemosporidian Lineages.

Abstract. Chaleekarn W, Duengkae P, Pongcharoen C, Sutummawong N, Nakmuenwai P, Siripin S, Chirachitmichi C, Kummoo W, Paansri P, Suksavate W. 2022. Effect of environmental factors at multiple landscape scales on bird community in riparian ecosystem at Mun-Chi River confluence, Thailand. Biodiversitas 23: 5194-5204. Wetland and riparian ecosystem is an important migratory stopover for land and water birds in the East Asian - Australasian Flyway. Understanding relationship patterns between bird communities and environmental factors at multi-spatial scales within a landscape context could contribute to the conservation and management of bird biodiversity in wetland ecosystems. The landscape metrics index is critical in revealing the relationship between the composition of bird communities and habitats at both local and landscape scales. This study aims to determine the effect of the environmental factors at different designated spatial scales on the composition of local bird communities in terms of species and feeding guilds. Our study conducted a bird survey using 227-point transects along 40 tracks across different land cover types surrounding the Mun-Chi River confluence. Canonical correspondence analysis (CCA) was used to quantify the association between bird communities, represented by species and feeding guilds, and environmental factors with the integration of multilevel habitat metrics. From the results, the CCA showed patterns of the community-environmental association at multiple scales of patch, class, and landscape characteristics with the proportional explanation of 54% and 61.82% for the composition of species and feeding guilds, respectively. The results indicated the premise that the majority of bird species respond to the habitat at the local scale. Large forest patches can maintain migratory and resident bird species. Moreover, most avian groups were arranged primarily in a large forest core area, forest area, and Shrubland PA. The results confirmed existing information on feeding guilds. The prediction map of the principal component of avian species composition was created from the association with the drivers of land use, including crops, perennial farmland, and water body on the edge of forests. Therefore, wetland management must be done at both local and landscape scales to preserve suitable avian habitats.

ABSTRACTAim Global climate change is increasingly influencing ecosystems. Long‐term effects on the species richness and composition of ecological communities have been predicted using modelling approaches but, so far, hardly demonstrated in the field. Here, we test whether changes in the composition of bird communities have been influenced by recent climate change.Location Europe.Methods We focus on the proportion of migratory and resident bird species because these groups are expected to respond differently to climatic change. We used the spatial relationship between climatic factors and bird communities in Europe to predict changes in 21 European bird communities under recent climate change.Results Observed changes corresponded significantly to predicted changes and could not be explained by the effects of spatial autocorrelation. Alternative factors such as changes in land use were tested in a first approximation as well but no effects were found.Main conclusions This study demonstrates that global climate change has already influenced the species richness and composition of European bird communities.

Prevalence and genetic diversity of avian haemosporidian parasites at an intersection point of bird migration routes: Sultan Marshes National Park, Turkey

AimThe role of migratory birds in the spread of parasites is poorly known, in part because migratory strategies and behaviours potentially affecting transmission are not easy to study. We investigated the dynamics of infection by blood parasites through the annual cycle of a long‐distance Nearctic–Neotropical migratory songbird to examine the role of this species in dispersing parasites between continents.LocationThe Americas.TaxonGrey‐cheeked Thrush (Catharus minimus, Aves, Passeriformes, Turdidae), Birds.MethodsWe used molecular and microscopy screening of haemosporidian parasites (Plasmodium,Haemoproteus, andLeucocytozoon) to examine the prevalence, distribution, and diversity of lineages through the annual cycle (breeding, migration, and wintering) of the grey‐cheeked thrush in North and Central America, Santa Marta mountains, the Andes, and the Amazon. We aimed to identify transmission areas, to examine the degree of sharing of haemosporidian lineages with resident birds in various areas and to assess the potential role of immunologically naïve juvenile individuals in parasite transmission.ResultsPrevalence and lineage diversity of haemosporidians varied significantly over time, being higher during breeding and fall and spring migration, and declining during wintering. Grey‐cheeked thrush shared few parasite lineages with tropical resident birds and slightly more lineages with other migratory and resident boreal species. We detected gametocytes in blood during spring migration stopover, but these were of lineages not found in resident tropical birds, indicating relapses of parasites transmitted elsewhere. Transmission likely occurs mostly on the breeding grounds, where juveniles and adults carried lineages restricted to closely related species of thrushes and other species of boreal birds.Main conclusionsLong‐distance migratory songbirds are likely not important dispersers of blood parasites because there are ecological and evolutionary barriers to the interchange of parasites across vastly separated areas. Further work with thorough spatial and temporal sampling across other species, and considering the role of vectors, is necessary to understand the ecological and evolutionary factors explaining the distribution of parasites over broad scales.

One of the main management strategies of China’s nature reserve is “zonation”, dividing reserves into three zones (core, buffer, and experimental zones) to which different levels of restrictions on anthropogenic activities are applied. While zonation has a positive effect on the conservation of target species, it is unclear whether management zones can be effective in conserving biodiversity. Using bird data collected from five national nature reserves of Guangdong province in China during 2018–2019, we investigated how management zones and reserves are associated with bird diversity and community composition. We considered species richness, the community-weighted mean (CWM) values of 10 single traits, and beta diversity based on 2 dissimilarity indices (Jaccard and Bray–Curtis). The overall effects of zone management were weak or insignificant. Species richness and the CWMs of most traits were not associated with zone (p > 0.08). Reserve itself was a strong factor influencing bird traits. Dissimilarity indices also showed variations in bird community composition between reserves in the north region and those in the south region, which were largely contributed by the turnover component of beta diversity (p ≥ 0.06 for nestedness and p ≤ 0.03 for turnover in both dissimilarity indices). The dominance of turnover indicates that these reserves could be equally important to maintain regional bird diversity, requiring a multiple-site management plan. Our study also suggests that current zoning designations of the five reserves may not be as effective in conserving bird species diversity and traits; however, caution is needed due to the limitations of our study design, such as potential observer effect and insufficient sampling effort.

Windbreaks often form networks of forest habitats that improve connectivity and thus conserve biodiversity, but little is known of such effects in the tropics. We determined bird species richness and community composition in windbreaks composed of remnant native vegetation amongst tea plantations (natural windbreaks), and compared it with the surrounding primary forests. Fifty-one, ten-minute point counts were conducted in each habitat type over three days. Despite the limited sampling period, our bird inventories in both natural windbreaks and primary forests were nearly complete, as indicated by bootstrap true richness estimator. Bird species richness and abundance between primary forests and windbreaks were similar, however a difference in bird community composition was observed. Abundances of important functional groups such as frugivores and insectivores did not vary between habitat types but nectarivores were more abundant in windbreaks, potentially as a result of the use of windbreaks as traveling routes, foraging and nesting sites. This preliminary study suggests that natural windbreaks may be important habitats for the persistence of bird species in a production landscape. However, a better understanding of the required physical and compositional characteristics for windbreaks to sustain bird communities is needed for effective conservation management.

Avian haemosporidians are parasites with great capacity to spread to new environments and new hosts, being considered a good model to host-parasite interactions studies. Here, we examine avian haemosporidian parasites in a protected area covered by Restinga vegetation in northeastern Brazil, to test the hypothesis that haemosporidian prevalence is related to individual-level traits (age and breeding season), species-specific traits (diet, foraging strata, period of activity, species body weight, migratory status, and nest shape), and climate factors (temperature and rainfall). We screened DNA from 1,466 birds of 70 species captured monthly from April 2013 to March 2015. We detected an overall prevalence (Plasmodium/Haemoproteus infection) of 22% (44 host species) and parasite’s lineages were identified by mitochondrial cyt b gene. Our results showed that migration can be an important factor predicting the prevalence of Haemoproteus (Parahaemoproteus), but not Plasmodium, in hosts. Besides, the temperature, but not rainfall, seems to predict the prevalence of Plasmodium in this bird community. Neither individual-level traits analyzed nor the other species-specific traits tested were related to the probability of a bird becoming infected by haemosporidians. Our results point the importance of conducting local studies in particular environments to understand the degree of generality of factors impacting parasite prevalence in bird communities. Despite our attempts to find patterns of infection in this bird community, we should be aware that an avian haemosporidian community organization is highly complex and this complexity can be attributed to an intricate net of factors, some of which were not observed in this study and should be evaluated in future studies. We evidence the importance of looking to host-parasite relationships in a more close scale, to assure that some effects may not be obfuscated by differences in host life-history.

Forest management plans offer valuable data on forest species composition and structure, useful for large-scale bird conservation. We examined the relationship between bird community diversity and five vegetation characteristics from management plans in Krkonoše Mts. National Park. Bird communities were surveyed from 2012 to 2014 using the point method on 285 plots (radius 100 m). We analyzed songbirds, woodpeckers, and pigeons. The vegetation characteristics were divided into composition (tree species proportion, soil-based phytocoenosis, and target vegetation type) and structure (vertical tree layering and remotely sensed heights). Bird species richness was used as a diversity measure. Redundancy analysis (RDA) tested the impact of vegetation characteristics on bird community composition. Higher bird diversity was linked to deciduous forests, particularly beech, in multi-layered stands (20–40 m height) on rich soils. In contrast, lower diversity occurred in spruce-dominated stands with Scots pine, waterlogged soils, and low vegetation (<0.5 m). All vegetation characteristics correlated significantly with bird community diversity and composition. Our findings demonstrate that forest management data can help identify key variability sources in bird communities, aiding in large-scale monitoring and landscape planning. Beyond tree composition and structure, phytocoenological characteristics provide useful insights for conservation.

Fire ecology for the 21st century: Conserving biodiversity in the age of megafire

In Bolivia dry forests are distributed extensively in the southeastern lowlands and extend into the country's northern and southern Andes in rain-shadowed intermontane valleys, where they often form habitat islands. We examined the biogeography and composition of bird communities at 14 Andean and seven lowland dry forest localities in Bolivia. To minimise biases, analyses considered only core speciessensu Remsen (1994) of zonal vegetation types. Of a total of 608 recorded species, 454 were zonal forest core species and 99 (22 %) typical dry forest species. Core species richness varied from 65 to 156 at individual sites. One species occurred at all sites and 154 (34 %) at a single locality each; this tendency was most evident in the northern Bolivian Andes where 46 % of core species were recorded only once. Comparisons of species composition showed that sites in the northern valleys were the most heterogeneous and distinct. Localities in the southern valleys were the most homogeneous with affinities to lowland dry forests; the latter separated into Velasco forest and Chaco woodland sites, respectively. A continuous ordination of sites revealed a steep gradient from large habitat areas in the dry southeastern lowlands to small, relatively humid Andean habitat islands in the northwest. Typical dry forest species were most prevalent in large habitat areas in the dry south, whereas typical humid forest species predominated in the relatively humid northern Andean habitat islands. Frugi-granivores and nectarivores such as pigeons and doves, hummingbirds, and emberizid finches were most prevalent at Andean sites, whereas insectivores made relatively greater contributions to lowland bird communities. The biogeographical affinities of Bolivian dry forest birds are varied. Overall, lowland birds gradually decreased and Andean species gradually increased with elevation, which was most pronounced in the southern Bolivian Andes; we found no elevational threshold of increased avifaunal turnover. An examination of range limits of typical dry forest species revealed a pronounced northwestward reduction of the dry forest avifauna from Chaco lowlands to small, isolated valleys in the northern Bolivian Andes. With seven species restricted to the Andean dry forests of Bolivia, this area has a considerably higher level of endemism than the Chaco. Andean dry forests were colonised by lowland species in two different ways. In the southern valleys and upper northern valleys, dry forest species ascended directly from the adjacent Chaco. The lower northern valleys were probably colonised by dry forest species during drier and cooler periods of the Pleistocene that resulted in expansions of seasonally dry tropical forest in Amazonia.

The article supports the hypothesis that the balance between anthropogenic and climate change-induced impacts on bird communities in the Baltic States has recently shifted towards a more pronounced climate impact. The results suggest that a climate warming-induced change in the composition of bird communities is not a universal process: it is a spatial and species-specific process. The article demonstrates that the impact of climate change on moist habitat birds is more dramatic than that on wetland, water and terrestrial birds. Birds of moist habitats predominate among the species with decreasing Lithuanian populations on the southern periphery of the species range. A list of affected bird species is presented and a new conception for more effective bird protection is introduced.

Migratory animals likely play an important role in the geographic spread of parasites. In fact, a common assumption is that parasites are potentially transmitted by migratory animals at temporary stopover sites along migratory routes, yet very few studies have assessed whether transmission at stopover sites can or does occur. We investigated the potential for a group of vector-transmitted parasites, the avian haemosporidians, to be transmitted during migratory stopover periods at Rushton Woods Preserve in Pennsylvania, USA. Using an analysis of 1454 sampled avian hosts, we found that while a core group of abundant haemosporidians was shared between local breeding birds and passing migrants, the parasite community of migratory birds at Rushton was distinct from that of local breeding birds and showed similarity to a previously sampled boreal forest haemosporidian community. Haemosporidians that were unique to passing migratory birds were associated with sampling sites in North America with cooler summer temperatures than haemosporidians that are transmitted at Rushton, suggesting that the transmission of these parasites may be restricted to high-latitude regions outside of our temperate stopover site. We also found that the abundance of mosquitoes in our study region is offset from that of migratory bird abundance during avian migratory periods, with the peak period of bird migration occurring during periods of low mosquito activity. Collectively, these findings suggest that although abundant haemosporidians are possibly transmitted between local and passing migratory birds, a combination of biotic and abiotic factors may constrain haemosporidian transmission during avian stopover at our study site.

Studies on avian haemosporidia are on the rise, but we still lack a basic understanding of how ecological and evolutionary factors mold the distributions of haemosporidia among species in the same bird community. We studied the structure and organization of a local avian haemosporidian assemblage (genera Plasmodium and Haemoproteus) in the Cerrado biome of Central Brazil for 5 years. We obtained 790 blood samples from 54 bird species of which 166 (21%) were infected with haemosporidians based on molecular diagnostics. Partial sequences of the parasite cytochrome b gene revealed 18 differentiated avian haemosporidian lineages. We also analysed the relationship of life-history traits (i.e., nesting height, migration status, nest type, sociality, body mass, and embryo development period) of the 14 most abundant bird species with the prevalence of avian haemosporidia. It was found that host species that bred socially presented a higher prevalence of Haemoproteus (Parahaemoproteus) than bird species that bred in pairs. Thus, aspects of host behaviour could be responsible for differential exposure to vectors. The assemblage of avian haemosporidia studied here also confirms a pattern that is emerging in recent studies using molecular markers to identify avian haemosporidians, namely that many lineages are host generalists.

Moving riparian management guidelines towards a natural disturbance model: An example using boreal riparian and shoreline forest bird communities

To meet the growing demand for chocolate, cocoa (Theobroma cacao) agriculture is expanding and intensifying. Although this threatens tropical forests, cocoa sustainability initiatives largely overlook biodiversity conservation. To inform these initiatives, we analyzed how cocoa agriculture affects bird diversity at farm and landscape scales with a meta‐analysis of 23 studies. We extracted 214 Hedges' g* comparisons of bird diversity and 14 comparisons of community similarity between a forest baseline and 4 farming systems that cover an intensification gradient in landscapes with high and low forest cover, and we summarized 119 correlations between cocoa farm features and bird diversity. Bird diversity declined sharply in low shade cocoa. Cocoa with >30% canopy cover from diverse trees retained bird diversity similar to nearby primary or mature secondary forest but held a different community of birds. Diversity of endemic species, frugivores, and insectivores (agriculture avoiders) declined, whereas diversity of habitat generalists, migrants, nectarivores, and granivores (agriculture associates) increased. As forest decreased on the landscape, the difference in bird community composition between forest and cocoa also decreased, indicating agriculture associates replaced agriculture avoiders in forest patches. Our results emphasize the need to conserve forested landscapes (land sparing) and invest in mixed‐shade agroforestry (land sharing) because each strategy benefits a diverse and distinct biological community.