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Wetland is a suitable habitat for water birds, and it enhances cultural ecosystem services. But the rapid transformation of such habitat, especially in floodplain environments, is an emerging crisis. Wetland reclamation and fragmentation are two major issues leading to poor habitat and landscape. The present paper aimed to explore the spatio-temporal changes in the suitability of wetland bird habitat, wetland landscape pattern, and the connection between them. Two wetlands, including a wetland of national importance, were taken as cases for this study. Time series Landsat and Sentinel images were taken for developing modeling parameters and Land Use Land Cover (LULC) for the years 2016 and 2020. The first transformation of wetland was accounted from the LULC maps of both years. Machine learning algorithm-based spatial models were developed for mapping the poor landscape condition of the existing wetland parts. Finally, semi-subjective analytic hierarchy approach (AHP)-based models were developed for assessing waterbird habitat suitability. Results demarcated more than 48% area belonging primarily to edges and tiny patches of wetlands under a poor state in 2020. Although the total wetland area was reduced between 2016 and 2020, the wetland area found to be highly suitable habitat increased from 25.5 to 59.44% of the total area during that period. The suitability of edge-preferring bird habitat showed a 10% increase. The increasing poverty of the landscape was caused by declining edge-preferring bird habitat suitability. From 1990 to 2020, 27% of wetlands were converted to single-cropped lands, and 5% were converted to multi-cropped agricultural land. Since the study spatially identified the potential suitable area and trend of wetland habitat transformation, this could help policymakers define suitable planning for the restoration and conservation of such promising bird habitat. [ABSTRACT FROM AUTHOR]

Our research endeavors to evaluate the precise ramifications of climate change on Iran's protected regions, utilizing species distribution modeling to anticipate the effects of climate change on 394 bird species, 157 plant species, 72 reptiles, and 20 mammals across two climate change scenarios: SSP245 and SSP585 in 2070. Subsequently, we employed binary species distribution maps to determine the extent of overlap between 125 protected areas, 27 wildlife refuges, and 15 national parks and species distribution, quantifying the proportion of these areas encompassed by their distribution. We found that under the SSP585 scenario, 174 bird species could experience a 319% expansion in suitable habitats, while 220 species could decline by 57.1%. Among plants, 16 species are projected to grow by 40.3%, whereas 141 species may decrease by 68.8%. Reptiles could experience an increase of 279.1% in 24 species, with a 66.6% decrease in 48 species, while mammals may witness a significant increase of 147.3% in 5 species, but a 71.8% decrease in 15 species. Also, under the SSP585 scenario, in national parks, bird coverage declines from 32.2% (current) to 19.9%, plants from 24.2 to 13.2%, reptiles from 18.4 to 6.8%, and mammals from 17.7 to 10%. In wildlife refuges, birds decrease from 9.7 to 5.7%, plants from 10.9 to 4.6%, reptiles from 12.9 to 2.5%, and mammals from 7.4 to 4.3%. In protected areas, birds drop from 29.3 to 20.4%, plants from 27.7 to 12.5%, reptiles from 18.7 to 9.7%, and mammals from 24 to 12.1%. The low overlap of species with national parks, wildlife refuges, and protected areas underscores the importance of re-evaluating and potentially expanding protected areas to ensure they encompass a broader range of habitats, particularly those that are underrepresented, to enhance the conservation of Iran's biodiversity amidst the challenges posed by climate change. [ABSTRACT FROM AUTHOR]

Ground nesting birds have declined throughout Europe, with the reduction of habitat structure in agricultural areas being a key contributing factor. Habitat structure is vital not only for providing food and suitable microclimates for these species but also limits nest predation. Field assessments of habitat structure have, historically, been the most common way of identifying areas of low nest predation. However, they are limited in their applicability over wide areas due to time, money, and logistics. Remotely sensed measures (e.g., recorded by a satellite) can address these issues. Normalised difference vegetation index (NDVI) is a measure of the 'greenness' of an area and correlates with habitat structure. We conducted an artificial nest experiment over three years (2019, 2020, 2023) in Baden, Austria to test the relationship of NDVI to nest predation in an agricultural landscape. Critically, we compared whether NDVI could predict nest predation as well as locally recorded variables (ground cover, vegetation height, etc,). We report that NDVI performs equally well at predicting nest predation, with predation decreasing with higher values of NDVI, signifying greater habitat structure. This was supported by our finding that predation probability decreased with greater ground cover (a locally recorded variable). Additionally, we found that areas with greater partridge numbers had higher predation and circumstantial evidence that birds are the primary predator in our study area. Overall, our study shows that satellite-derived measures of habitat structure have untapped potential in identifying areas of high nest predation for European ground nesting birds in agricultural landscapes. [ABSTRACT FROM AUTHOR]

Migratory bird populations are declining globally at alarming rates. Non-breeding site conditions affect breeding populations, but generalising non-breeding habitat conditions over large spatial regions cannot address potential fine-scale differences across landscapes or local populations. Plumage characteristics can mediate the effects of environmental conditions on individual fitness. However, whether different phenotypes use distinctive non-breeding sites, and whether they respond to non-breeding site conditions differently remains largely unknown. Stable isotopes (δ13C, δ15N, δ2H) of inert tissues are useful to infer habitat characteristics and geographic origins where those tissues were grown. We collected winter-grown feathers from pied flycatchers (Ficedula hypoleuca) on their breeding grounds over several years from males whose dorsal plumage colouration ranged continuously from brown to black and assessed their stable isotope values as proxies of local habitat conditions. Based on feather δ2H profiles we found that browner males spent their non-breeding season in drier habitats than black males. Assignment to origin analysis shows potential regional non-breeding ground separation between differently coloured males. High within-individual repeatability of both δ13C and δ15N indicate the pied flycatcher males return yearly to similar areas. Blacker males were more likely to return to the breeding grounds after dry years compared with brown males. The opposite was found in wet years. Our study demonstrates that different phenotypes are exposed to different non-breeding site conditions which can differentially affect individual survivorship. This has important ramifications for population dynamics under predicted climate change scenarios where especially brown phenotype pied flycatcher males may be under a risk of decreasing. [ABSTRACT FROM AUTHOR]

Intensification and homogenization of agricultural landscapes have led to a strong decline in European farmland birds. Agroforestry systems, which were widespread in the past, are regaining attention as they could return structural heterogeneity to agricultural landscapes. However, few studies focus on the effects of such systems on biodiversity and especially bird diversity. We hypothesized that agroforestry systems host a higher alpha and beta diversity of birds compared to open agriculture as well as distinct bird communities. Moreover, we expected that bird communities in temperate Europe and the Mediterranean are differently affected by agroforestry systems. In this study, we assessed breeding bird diversity via audio recordings in nineteen mature agroforestry plots, comprising both silvoarable and silvopastoral systems distributed across seven countries in temperate and Mediterranean Europe. For comparison, bird diversity was also assessed in nearby open agricultural land, forests, and orchards. Bird species richness in agroforestry was more than doubled compared to open agricultural land and similar to the diversity found in forests and orchards. Community composition and within-habitat beta diversity differed between the habitat types and between European regions. While temperate agroforestry systems hosted generalist and woody habitat species, bird communities in Mediterranean agroforestry were composed of species from both open and woody habitats. Beta diversity was significantly higher in agroforestry than in open agriculture in temperate systems but not in the Mediterranean. Our study demonstrates that agroforestry systems represent a valuable habitat for breeding birds in European agricultural landscapes. A wider adoption of these systems could thus contribute to halting and reversing the decline in bird diversity, especially in temperate agricultural landscapes. [ABSTRACT FROM AUTHOR]

The red fox (Vulpes vulpes) is a widely distributed generalist meso-predator implicated in declines of wading bird populations. In the wet grassland habitats where waders breed, wildlife managers work to mitigate fox predation risk to waders during the nesting period through lethal and non-lethal control methods. However, limited knowledge on fox movement ecology in these habitats makes it difficult to design effective management strategies. We used GPS telemetry to understand fox home range size, daily activity and movement patterns, and how these metrics may vary among wet grassland sites with different management. We caught and GPS-tagged 35 foxes in the March–June wader nesting period on two wet grassland sites in central southern England; Britford during 2016/17 and Somerley during 2018/19. We estimated home range areas from location data using local convex hulls, and from these estimates we derived the minimum fox density at each site and year. Daily activity patterns and movement behaviour of each fox were obtained using both telemetry and trail camera data. Mean fox home range area at Britford (0.21 km2, SE = 0.025) was significantly smaller than at Somerley (0.68 km2, SE = 0.067), and estimated minimum densities were around four times higher (Britford = 10.6 foxes/km2, Somerley = 2.4 foxes/km2). Foxes were more active and moved faster during twilight and night hours, but both telemetry and camera data indicate they were also active for one-third of daylight hours. Distances moved per day were variable between foxes but generally smaller at Britford. We also found evidence for dispersal during spring, with movements of up to 19 km per day. Home ranges at both wet grassland sites were smaller than comparable sites elsewhere. These indicated foxes were living at exceptionally high densities at Britford, where there is no fox control, increased food availability and where waders no longer breed. Spatio-temporal movement patterns were closely related to home range metrics, with higher levels of fox activity at Somerley, where home ranges were larger. The movements of itinerant and dispersing foxes during the nesting period suggests that lethal control would need to be very intensive to be effective. The likely anthropogenic food subsidy of fox density at Britford suggests that controlling access to similar food resources would help reduce predation pressure on breeding waders. [ABSTRACT FROM AUTHOR]

The Lesser Grey Shrike is a typical Palaearctic songbird for which we have limited knowledge of its migration ecology. All that is known about its non-breeding movements is inferred from observational data of birds on passage. The few available ring recovery data do not link breeding and African non-breeding grounds. By deploying two types of loggers, light-level geolocators and multi-sensor loggers, on birds from a declining Slovak breeding population, we present the first direct evidence for non-breeding grounds, loop migration, stopover sites and the timing of annual cycle events. With barometric data, we provide details on flight altitudes during migration. The two tracked birds migrated in a clear anti-clockwise loop to S Africa. Autumn migration tracks went through the Balkan Peninsula, Mediterranean Sea towards Libya with unusually long stays around N Chad and Niger. The next stopovers were in Angola, and the main non-breeding sites were in Botswana. Spring migration commenced on March 29 and April 7 and the birds took routes along East African countries, with stopovers later in Somalia and Saudi Arabia, before crossing the eastern Mediterranean Sea. Nocturnal migration dominated, but for three days in August, while crossing the Sahara Desert, the bird extended flights into the day with a sudden increase in flight altitudes at dawn. Flight altitudes were higher during barrier crossing and during the last phase of spring migration compared to the remaining periods, with the most extreme event recorded at 4530 m asl. [ABSTRACT FROM AUTHOR]

According to general urban ecological understanding, bird species richness declines in highly urban areas due to the increasing extent of built-up areas, and decreasing proportions of green areas. However, this hypothesis is mainly based on studies conducted in cities located in the Global North and rarely in the Global South. We aimed to assess whether existing conceptual understandings of drivers of bird species richness patterns within cities are similar across different regions, specifically Southern Asia (in the Global South) vs. Western Europe (in the Global North). Using avian occurrence data drawn from GBIF (gbif.org), we estimated resident bird species richness in 943 selected grid cells (each cell corresponding to approximately 1 km2 area) distributed in 24 cities, 13 in Southern Asia and 11 in Western Europe. We applied generalised linear mixed models to relate resident bird richness with different explanatory variables of gradients of urbanisation, habitat and climatic factors using the selected grid cells as sampling units. Our results showed that bird richness declined with increasing human built-up and settlement extent (imperviousness) in both regions, but this relationship was stronger in Southern Asia compared to Western Europe. Bird richness also sharply declined in urban areas located far from inland waterbodies, but only in Southern Asia. Our findings suggest that high imperviousness drives bird richness decline, but this process appears to be more pronounced in regions where rapid urbanisation is ongoing. Urban planning integrating green spaces throughout cities is crucial in Southern Asia, as it is in Western Europe, to benefit both people and biodiversity. [ABSTRACT FROM AUTHOR]

Mercury (Hg) contamination remains a significant environmental concern. In aquatic ecosystems, Hg can undergo methylation, forming its organic form, methylmercury (MeHg), which bioaccumulates and biomagnifies in the food chain, ultimately reaching the top predators, including waterfowl. The objective of this study was to investigate the distribution and levels of Hg in wing feathers, with a specific focus on evaluating heterogeneity in the primary feathers of two kingfisher species (Megaceryle torquata and Chloroceryle amazona). The concentrations of total Hg (THg) in the primary feathers of C. amazona individuals from the Juruena, Teles Pires, and Paraguay rivers were 4.724 ± 1.600, 4.003 ± 1.532, and 2.800 ± 1.475 µg/kg, respectively. The THg concentrations in the secondary feathers were 4.624 ± 1.718, 3.531 ± 1.361, and 2.779 ± 1.699 µg/kg, respectively. For M. torquata, the THg concentrations in the primary feathers from the Juruena, Teles Pires, and Paraguay rivers were 7.937 ± 3.830, 6.081 ± 2.598, and 4.697 ± 2.585 µg/kg, respectively. The THg concentrations in the secondary feathers were 7.891 ± 3.869, 5.124 ± 2.420, and 4.201 ± 2.176 µg/kg, respectively. The percentage of MeHg in the samples increased during THg recovery, with an average of 95% in primary feathers and 80% in secondary feathers. It is crucial to comprehend the current Hg concentrations in Neotropical birds to mitigate potential toxic effects on these species. Exposure to Hg can lead to reduced reproductive rates and behavioral changes, such as motor incoordination and impaired flight ability, ultimately resulting in population decline among bird populations. [ABSTRACT FROM AUTHOR]

Urbanization requires enormous amounts of material inputs especially sand to fulfilling the demands of the increasing human population through sand mining. It has negative environmental impacts in terms of physical, chemical, and biological aspects like river-associated biodiversity, especially on river dolphins, fishes, crocodiles, turtles, otters, and birds. The temporary sand islands of Rivers with their abundant food supplies for birds are ideal nesting grounds for a variety of avian species, like Indian Skimmer, Black-bellied Tern, River Tern, Great Thick-knee, and River Lapwing. Extensive sand mining is degrading the breeding grounds of these sandbar nesting birds which can eventually lead to their population decline. Inadvertent erosion of river beds and banks also may occur as a result of extreme extraction practices. The use of heavy machinery is also affecting the collective environment. Conservation priority areas can be identified using select birds as environmental indicators and model organisms for biodiversity conservation. Long-term avifaunal survey data could also be useful for effective monitoring of the changes in the riverine habitat quality and biodiversity. Increasing natural riparian vegetation and conservation awareness among local people could make a positive impact on conserving these habitats along with some of the threatened avian species. [ABSTRACT FROM AUTHOR]

Context: Urbanization and its associated impacts on biodiversity are increasing globally. There is a need to enhance our understanding of species responses to inform strategies for sustainable urbanization. Objectives: Three extensive bird monitoring campaigns took place over the last three decades in the city of Naples, Italy, providing a comprehensive longitudinal dataset to analyse occurrence trends of urban birds. We aimed to assess both species-specific and assemblage-level changes in urban birds according to land cover dynamics. Methods: We extracted bird data for the periods 1990–95, 2000–05, and 2014–18, and explored the spatial and temporal relationships between bird presence/avian assemblage composition, and land cover variation. Results: The species richness of breeding birds remained stable over time, despite a notable species turnover, influenced by changes in the species' key land cover classes. Species associated with forest and urban land cover tended to colonise the area, while those dependent on abandoned and cultivated areas decreased or went locally extinct. Birds changed their degree of dependence upon their key habitat type over time, as species from marginal and open habitat types needed larger amounts of habitat to persist within the area, while forest species showed an opposite trend. Conclusions: Habitat-driven changes in avian assemblages within the urban landscape led to an increase in forest-associated species, and a decrease in birds associated with declining habitat types. Our findings may inform urban planning to promote more wildlife-friendly cities, which for our study area should prioritise open and marginal habitats. [ABSTRACT FROM AUTHOR]

Data on the distribution and abundance of the Great Snipe in northwestern Russia and in neighboring Finland over the past 150 years are summarized. There was a decrease in the number of birds, which went from west to east, in this part of the range in the 20th century. The Finnish population declined to a critical level by the middle of the 20th century; a noticeable decline in the number of birds occurred in the 1960s–1970s in the Leningrad region and in the 1980s in Karelia. At present, the Great Snipe retains the status of a breeding and migratory species in the region, but its distribution area continues to shrink and break up into fragments, and its northern border has receded to the south and southeast. The Great Snipe is sporadically distributed throughout the Leningrad and Vologda regions, but it now breeds in separate isolated groups to the north of these borders: in Karelia and the Arkhangelsk region. In Karelia, the range boundary receded from 63° to 62° N, and it is limited to lands located near the shores of lakes Ladoga and Onega. In the western part of the Arkhangelsk region, birds are occasionally found up to 62°–63° N during breeding time; along the floodplain of the Northern Dvina, they reach Arkhangelsk; near the eastern border of the region, they go up to 65°; and in the western part of the Nenets Autonomous Okrug, up to 67° N. A lack of data does not allow us to indicate the exact boundary of the range of the species, but the obtained results can serve as a starting point for further studies of its distribution. [ABSTRACT FROM AUTHOR]

Globally, habitat loss has been deemed a major threat to wetland bird populations. However, the underlying mechanism of population declines and variations in the birds' vulnerability throughout their annual cycle is challenging to determine, yet critical for development of targeted conservation strategies. Over seven years, landscape water availability explained occupancy of breeding territories best when breeding performance, migratory performance, and annual survival of the White-naped Crane (Grus vipio) population in eastern Mongolia were studied. Also, the hatching success of eggs was positively correlated with water availability in addition to plant productivity. High ambient temperatures and large numbers of herder families (and hence more livestock) negatively affected hatching success. High water availability at Luan, a major stopover site increased migration speed during the cranes' northbound migration to their breeding grounds. In contrast, when water conditions were favorable, the birds stayed longer at the stopover site during southbound migration. Increased human density reduced the use of the stopover site during northbound migration. Finally, cranes arrived early at the breeding grounds when ambient temperature was high in northeast Mongolia. Combining these findings with historical trends in key environmental factors on their breeding grounds explains the general decline observed in this population of cranes in recent decades. Extrapolating our findings with future climate predictions, the outlook seems poor unless urgent action is taken. Knowledge of the mechanisms underlying White-naped Crane population decline in eastern Mongolia identified in this paper should improve the effectiveness of these actions. [ABSTRACT FROM AUTHOR]

Farmland bird populations have declined globally raising concerns over habitat loss for a wide range of species. In this study, we explored the significance of agroecosystems for birds at different temporal and spatial scales along the Cauvery delta region, South India. Our results recorded a wide range of 102 species, with passerines and wetland birds dominating the landscapes. Among the guild types, omnivores and insectivores were the well-represented groups followed by carnivores, granivores, frugivores, and nectarivores. Species richness and diversity were recorded higher during winter which could be associated with the maturing phase of rice paddies in the agroecosystem. There were significant differences recorded in species diversity and richness between the cropping period and the non-cropping periods, thus recognizing the high potential of paddy ecosystems in biodiversity conservation. The results of the multivariate analysis revealed that the diversity of birds in the agroecosystem was more influenced by the woody vegetation cover, crop cover, and field size; however, bird abundance was related to farm activities, plantations, and herbaceous cover surrounding the agroecosystem. Fewer generalist species revealed an interesting pattern of taxonomic homogenization with monoculture cropping patterns that could influence the adaptability and functional traits of the other species. The results of the study highlight that both HNV and the non-HNV zones attract a rich diversity of birds and the conservation of this traditional agricultural belt would aid in the conservation of threatened species and biodiversity globally. [ABSTRACT FROM AUTHOR]

For decades, we have observed a major biodiversity crisis impacting all taxa. Avian species have been particularly well monitored over the long term, documenting their declines. In particular, farmland birds are decreasing worldwide, but the contribution of pesticides to their decline remains controversial. Most studies addressing the effects of agrochemicals are limited to their assessment under controlled laboratory conditions, the determination of lethal dose 50 (LD50) values and testing in a few species, most belonging to Galliformes. They often ignore the high interspecies variability in sensitivity, delayed sublethal effects on the physiology, behaviour and life-history traits of individuals and their consequences at the population and community levels. Most importantly, they have entirely neglected to test for the multiple exposure pathways to which individuals are subjected in the field (cocktail effects). The present review aims to provide a comprehensive overview for ecologists, evolutionary ecologists and conservationists. We aimed to compile the literature on the effects of pesticides on bird physiology, behaviour and life-history traits, collecting evidence from model and wild species and from field and lab experiments to highlight the gaps that remain to be filled. We show how subtle nonlethal exposure might be pernicious, with major consequences for bird populations and communities. We finally propose several prospective guidelines for future studies that may be considered to meet urgent needs. [ABSTRACT FROM AUTHOR]

Vultures constitute globally the most rapidly declining group of birds. Across their wide distribution range, they share common ecological functions and unfavourable conservation status while being associated with varying habitats, lifestyles, cultural standing, and threats. We reveal conceptualisations about the emblematic yet critically endangered Egyptian vulture along its migratory flyway from the Balkans through the Middle East to Africa. Information was gathered through interviews, focus group discussions, and market surveys, with 420 people in 11 participating countries contributing overall. Our results showed that all vultures are recognised primarily for the environmental cleaning services, but the level of awareness differs between countries. Τhe Egyptian vulture has some perceptual advantages based on its white color, migratory nature, and endangered conservation status. This underlines its suitability as a charismatic flagship species that can potentially benefit other vulture species and thus enforce broader vulture conservation initiatives. [ABSTRACT FROM AUTHOR]

The reed belt around Lake Neusiedl is one of the largest connected reed areas in Europe, and thus bears crucial importance for the conservation of species depending on this habitat. In the last decades, a decline of reed harvesting has led to the formation of very old reed areas. Here we investigate how age and structure of degraded reed affect breeding bird species. We related extensive bird counts of eight species at 111 points to habitat measurements and reed age. Species differed in their preferred age class; for example, Great Reed Warblers Acrocephalus arundinaceus are found mainly in up to 4-year-old reed stands, while Little Crakes Zapornia parva prefer to settle in more than 14-year-old vegetation. We expected some species to be more common in older age classes, but our results demonstrate that large parts of the reed stands become too degraded even for these "old reed" specialists. Several bird species showed an inverse u-shaped relationship to habitat characteristics associated with reed die-back, e.g. accumulation of broken reed stems, occurrence of matted reed, low vegetation height or open water areas. At present, harvested areas are small and burning of reed is prohibited, and in the future, we expect more reed die-back with declining bird numbers. Missing ice cover in wintertime because of climate warming prevents sustainable cutting of these very old reed stands. We thus recommend a cautious introduction of fire management as a measure to secure this unique bird habitat. [ABSTRACT FROM AUTHOR]

Agricultural intensification has led to dramatic declines in bird populations. In particular, the acknowledged role of synthetic pesticides on direct bird intoxication or food resource depletion urges us to seek alternative crop protection methods. Pest exclusion netting systems have recently gained popularity among fruit growers as an efficient means of reducing pest attacks, allowing their transition to organic farming. Single-row exclusion nets, which only cover fruit trees and leave uncovered both the inter-row grassy strips and the hedges, are increasingly being used in apple orchards of Southern Europe. However, net-induced effects on wildlife remain unknown. This study is the first to assess the impacts of single-row exclusion nets on breeding bird communities. We hypothesized that the exclusion net effects would be weaker than those associated with synthetic pesticide use, except for bird species that forage in the tree canopy. We monitored breeding bird abundance, and species richness in 46 commercial apple orchards managed using integrated pest management (IPM) or organic standards with or without exclusion nets. We counted 705 birds belonging to 32 different species. Total bird abundance, the number of observed species, and the Chao1 estimate of species richness were influenced by orchard management strategy. Breeding bird assemblages in organic orchards were as numerous and diverse in both the presence and absence of exclusion nets. In contrast, both bird abundance and species richness were significantly decreased in IPM orchards. The abundance and species richness of bird assemblages and the abundance of a few individual species also increased with the number of hedgerows bordering the orchards. Our results demonstrate that single-row netting systems for organic farming represent an effective pest control strategy with no significant impact on bird communities and highlight the importance of hedgerows along the orchards' edges. [ABSTRACT FROM AUTHOR]

Human settlements represent important year-round habitats for many declining farmland birds; however, detailed knowledge of species-specific habitat associations is crucial for effective conservation of individual species. In this study, we examined the effect of environmental factors on the occurrence, population density, and habitat associations of three sedentary granivorous farmland bird species (house sparrow Passer domesticus, tree sparrow Passer montanus, and Eurasian collared dove Streptopelia decaocto) during the breeding season within an urban environment and compared the results with a previously published study carried out during winter. To fulfil our aims, we used a comprehensive dataset from a nation-wide monitoring program focused on the studied species in the Czech Republic covering the period 2010–2016 and including a total of 162 human settlements (330.3-km length of transect). House sparrow was the most numerous and common species recorded on the studied transects, followed by tree sparrow and Eurasian collared dove. The population density of house sparrows and Eurasian collared doves was positively correlated with the proportion of farmsteads, and the population density of tree sparrows was positively correlated with proportion of grasslands. The occurrence of house sparrows and Eurasian collared doves increased with higher proportion of buildings and small-scale farms, whereas occurrence of tree sparrows increased with higher proportion of small-scale farms and woody plants. Habitat preference analyses demonstrated that house sparrow and Eurasian collared dove primarily preferred buildings, and tree sparrows preferred small-scale farms. Arable habitats were generally avoided by all studied species. Based on species-specific occurrence and habitat associations, several management measures may be adopted to support declining populations of the studied species, as well as whole bird communities inhabiting urban environments. [ABSTRACT FROM AUTHOR]

Anguillid eel populations have declined dramatically over the last 50 years in many regions of the world, and numerous species are now under threat. A critical life-history phase is migration from freshwater to distant oceans, culminating in a single life-time spawning event. For many anguillids, especially those in the southern hemisphere, mystery still shrouds their oceanic spawning migrations. We investigated the oceanic spawning migrations of the Australasian short-finned eel (Anguilla australis) using pop-up satellite archival tags. Eels were collected from river estuaries (38° S, 142° E) in south-eastern temperate Australia. In 2019, 16 eels were tracked for up to about 5 months, ~ 2620 km from release, and as far north as the tropical Coral Sea (22° S, 155° E) off the north-east coast of Australia. Eels from southern Australia appeared to access deep water off the Australian coast via two main routes: (i) directly east via Bass Strait, or (ii) south-east around Tasmania, which is the shortest route to deep water. Tagged eels exhibited strong diel vertical migrations, alternating between the warm euphotic zone (~ 100–300 m, 15–20 °C) at night and the mesopelagic zone (~ 700–900 m, 6–8 °C) during the day. Marine predators, probably lamnid sharks, tuna, or marine mammals, ended many eel migrations (at least ~ 30%), largely before the eels had left the Australian continental shelf. The long and risky marine migrations of Australasian eels highlight the need for better information on the processes contributing to eel mortality throughout the life cycle, including the impacts of future changes to oceanic currents, predator abundance and direct anthropogenic disturbances. [ABSTRACT FROM AUTHOR]

Natural sounds, and bird song in particular, play a key role in building and maintaining our connection with nature, but widespread declines in bird populations mean that the acoustic properties of natural soundscapes may be changing. Using data-driven reconstructions of soundscapes in lieu of historical recordings, here we quantify changes in soundscape characteristics at more than 200,000 sites across North America and Europe. We integrate citizen science bird monitoring data with recordings of individual species to reveal a pervasive loss of acoustic diversity and intensity of soundscapes across both continents over the past 25 years, driven by changes in species richness and abundance. These results suggest that one of the fundamental pathways through which humans engage with nature is in chronic decline, with potentially widespread implications for human health and well-being. Birdsong has long connected humans to nature. Historical reconstructions using bird monitoring and song recordings collected by citizen scientists reveal that the soundscape of birdsong in North America and Europe is both quieter and less varied, mirroring declines in bird diversity and abundance. [ABSTRACT FROM AUTHOR]

A concept of retrieving and monitoring groundwater dynamics was introduced via metrics derived using Remote Sensing (RS) and Geographic Information Systems (GIS) in the basaltic region, namely the Euclidian distance between neighbouring irrigation wells, area irrigated per well, well density and cluster analysis. In a representative Nagjhari watershed (14823 ha) located in Maharashtra state, India, temporal Google Earth images were interpreted visually to retrieve the periodic (2007, 2013, 2017), historical dugout well related data. During the decade, the number of wells increased by 429 (64%) with a 7% decrease in irrigated area, implying a greater number of competing users, tapping the same aquifer leading to the increased cost of irrigation. In 2007, functional wells (368) outnumbered defunct wells (303). By 2017, the reversal was far greater with 698 defunct wells compared to 399 functional wells. Clusters of 5–10, 10–15, and >15 number of wells respectively with 500 m proximity showed a common trend of a rising number of defunct wells (303 to 698), a decline in the total irrigated area in the watershed (from 517 to 479 ha), and irrigated area per unit well (from 1.41 to 1.23 ha) accompanied by a decrease in inter-well distance from 250 to 110 m. The well density increased from 0.035 to 0.25 units per ha. Neural clustering proved effective in discovering and delineating an aquifer located between 310–330 m contour classes. Three 'hot spots' of high well density, lower inter-well distance, and irrigated area per well were mapped. Observation wells monitored by the Central Ground Water Board were located within 460 m from the functional wells raising concerns about their representative character. An alarming trend of the rising number of competing groundwater users, increasing demand but actual use limited by aquifer yield potential was noted with negative influence on well density, and investment of about INR 34.55 million wasted over a decade. [ABSTRACT FROM AUTHOR]

Knowledge of feeding ecology of declining species, such as farmland birds, is essential to address their conservation requirements, especially when their habitats are suffering important reductions of trophic resources. In this study, we apply a metabarcoding approach to describe the diet composition of six of the most significant farmland birds inhabiting European cereal pseudo-steppes: little bustard, great bustard, pin-tailed sandgrouse, black-bellied sandgrouse, red-legged partridge, and common quail. We further studied seasonal diet variations (autumn to spring) in all species but the common quail, whose diet was studied during spring and summer. We show that study species´ diets mostly consisted of plants, although in the case of little bustard and great bustard arthropods are also highly relevant. Among arthropods, we found high proportions of thrips, arachnids, and springtails, which were previously unreported in their diet, and some taxa that could be used as antiparasitic food. Moreover, we report that little bustard's diet is the least rich of that of all studied species, and that diet of all these species is less diverse in winter than in autumn and spring. Diet composition of these declining species supports the importance of natural and semi-natural vegetation and landscape mosaics that can provide a wide variety of arthropods, plants, and seeds all year-round. [ABSTRACT FROM AUTHOR]

Many natural ecosystems in tropical regions are under immense anthropogenic pressure, mostly connected with forest logging. However, several other factors may play important roles. From a conservation perspective, it is important to assess the impacts of these changes in biodiversity hotspots, but adequate data are scarce. We repeated point-count bird monitoring at 29 count-points in an Afromontane ecosystem near Big Babanki in NW Cameroon after a 13-year period. Between the censuses in 2003 and 2016, we found a decrease in bush cover and an increase in herb layer, whereas tree cover did not change. Consequently, we found a decrease in the total number of bird individuals per count-point driven by a decrease in the abundances of shrubland species, mainly nectarivores and granivores (e.g., Northern double-collared sunbird, Black crowned waxbill, Oriole finch, Thick-billed seedeater or Baglafecht weaver). In general, the decrease was found in nectarivore species that depend on flowering bushes (mainly Hypericum spp.). Similarly, we found a decrease in approximately half of the granivore species that often use bush cover for nesting and feeding. Additionally, one large fruit feeding bird, the Great blue turaco, became nearly extinct probably due to hunting activity. The observed contraction of bush cover accompanied by shrubland bird declines possibly results from a decrease in humidity in the area that was indicated by remote sensing. This may be caused by montane forest loss and fragmentation during the second half of the 20th Century. Our findings uncover the long-term consequences of deforestation which are rarely considered, even though they impact key ecosystem functions. [ABSTRACT FROM AUTHOR]

Population sizes of endemic songbirds on Kaua'i have decreased by an order of magnitude over the past 10–15 years to dangerously low numbers. The primary cause appears to be the ascent of invasive mosquitoes and Plasmodium relictum, the agent of avian malaria, into elevations formerly free of introduced malarial parasites and their vectors. Given that these declines in native bird populations appear to be continuing, last resort measures to save these species from extinction, such as conservation breeding, are being implemented. Using 200–1439 SNPs from across the genome, we assessed kinship among individuals, levels of genetic variation, and extent of population decline in wild birds of the two most critically endangered Kaua'i endemic species, the 'akikiki (Oreomystis bairdi) and 'akeke'e (Loxops caeruleirostris). We found relatively high genomic diversity within individuals and little evidence of spatial population genetic structure. Populations displayed genomic signatures of declining population size, but individual inbreeding coefficients were universally negative, likely indicating inbreeding avoidance. Diversity within the founding conservation breeding population largely mirrored that in the wild, indicating that genetic variation in the conservation breeding population is representative of the wild population and suggesting that the current breeding program captures existing variation. Thus, although existing genetic diversity is likely lower than in historical populations, contemporary variation has been retained through high gene flow and inbreeding avoidance. Nonetheless, current effective population size for both species was estimated at fewer than 20 individuals, highlighting the urgency of management actions to protect these species. [ABSTRACT FROM AUTHOR]

Natural sensory environments, despite strong potential for structuring systems, have been neglected in ecological theory. Here, we test the hypothesis that intense natural acoustic environments shape animal distributions and behavior by broadcasting whitewater river noise in montane riparian zones for two summers. Additionally, we use spectrally-altered river noise to explicitly test the effects of masking as a mechanism driving patterns. Using data from abundance and activity surveys across 60 locations, over two full breeding seasons, we find that both birds and bats avoid areas with high sound levels, while birds avoid frequencies that overlap with birdsong, and bats avoid higher frequencies more generally. We place 720 clay caterpillars in willows, and find that intense sound levels decrease foraging behavior in birds. For bats, we deploy foraging tests across 144 nights, consisting of robotic insect-wing mimics, and speakers broadcasting bat prey sounds, and find that bats appear to switch hunting strategies from passive listening to aerial hawking as sound levels increase. Natural acoustic environments are an underappreciated niche axis, a conclusion that serves to escalate the urgency of mitigating human-created noise. An experimental study finds that birds and bats avoid whitewater river noise, and that intense noise reduces bird foraging activity and causes bats to switch hunting strategies. Overlap between noise and song frequency predicts bird declines until high levels where other mechanisms appear important. [ABSTRACT FROM AUTHOR]

Background: Habitat heterogeneity clearly distinguished in terms of availability of food and habitat resources and landscape features (natural or human-modified) play a crucial role in the avian species composition and population structure. To examine this, a study was carried out in Bhubaneswar, India, to understand the ecological niche distinction in birds based on habitat heterogeneity. Regular sampling was conducted in 30 sampling sites covering six different habitat types in a predominantly urban landscape of Bhubaneswar for understanding the ecological niche in birds. The birds were classified into 11 types of foraging guilds. Results: The insectivorous guild had the highest bird species richness (181 species) and the omnivorous guild had the lowest (11 species). The piscivorous guild and wetland habitat had the strongest linkage, followed by the insectivorous guild and agricultural land. The frugivorous guild was significantly correlated with forest habitats (r = 0.386, p < 0.01) and park and garden habitats (r = 0.281, p < 0.01). This urban area hosted a higher number of bird species in certain habitat types, viz., agricultural lands (52%, 115 species) and forest patches (50%, 111 species). Conclusion: The present study highlights the importance of agricultural lands, forest patches, parks and gardens, and wetlands inside the cityscape for supporting avifauna. It is therefore suggested that such habitats should be conserved inside an urban area to protect native avifauna. Thus, the city development plan must invariably include strategies for conserving the forest patches inside the urban area. Measures must be taken to restrain the degradation of agricultural lands and reduce their utilization for non-agricultural purposes, which will help in further reducing the bird population decline in the urban landscape. [ABSTRACT FROM AUTHOR]

Previous studies reported that habitat degradation and alteration (e.g., urbanization, agricultural intensification, and abandonment, as well as contaminants) led to frog population decline, which has become a serious global ecological issue. However, the combined effects of midsummer drainage and agricultural modernization on tadpole populations are rarely investigated. In this study, we evaluated the effects of human activity-induced water management and the type of drainage system in paddy fields on the survival of Zhangixalus arboreus in central Japan. Our results revealed that the midsummer drainage negatively affected tadpole survival, whereas the modern drainage system showed no influence. This study provides a useful way to better understand the survival of frog populations in the paddy field ecosystems. [ABSTRACT FROM AUTHOR]

Agriculture intensification drives changes in bird populations but also in the space use by farmland species. Agriculture in Eastern Europe still follows an extensive farming model, but due to policy shifts aimed at rural restructuring and implementation of government subsidies for farmers, it is being rapidly intensified. Here, we aimed to document the ranging behaviour and habitat use of a declining farmland bird of prey—Montagu's Harrier—and to compare it to findings from Western Europe. In 2011–2018, 50 individuals were followed with GPS loggers in Eastern Poland to study species spatial ecology. We found home ranges (kernel 90%) to be considerably large: 67.3 (± 42.3) km2 in case of males, but only 4.9 (± 6.1) km2 in females. Home ranges overlapped by 40%, on average, with other males in colonies and by 61%, on average, between consecutive breeding seasons of a particular male. The average daily distance travelled by males and females reached, respectively, 94.5 and 45.3 km, covering a daily home range of 32.3 and 3.1 km2. Individuals foraged up to 35 km from nests (3.5 km on average). Daily distance travelled and daily home ranges varied across the breeding season, in case of females being shortest in July, but sharply increasing in August. Also, individuals with breeding success had higher daily distance travelled but smaller daily home ranges. Average harriers' distance to nest was generally increasing over the season, but was also changing over time of day: birds were closest to nest during night time, but at the end of the season, males roosted up to 16 km from the nest. While foraging males slightly preferred grasslands, higher elevation and smaller land-use patches, they avoided slopes and proximity of roads. We conclude that the surprisingly large home ranges of breeding harriers may suggest reduced prey availability or high fragmentation of hunting areas, both driving birds to utilise large areas and potentially contributing to population decline. [ABSTRACT FROM AUTHOR]

Context: Given widespread population declines of birds breeding in North American grasslands, management that sustains wildlife while supporting rancher livelihoods is needed. However, management effects vary across landscapes, and identifying areas with the greatest potential bird response to conservation is a pressing research need. Objectives: We developed a hierarchical modeling approach to study grassland bird response to habitat factors at multiple scales and levels. We then identified areas to prioritize for implementing a bird-friendly ranching program. Methods: Using bird survey data from grassland passerine species and 175 sites (2009–2018) across northeast Wyoming, USA, we fit hierarchical community distance sampling models and evaluated drivers of site-level density and regional-level distribution. We then created spatially-explicit predictions of bird density and distribution for the study area and predicted outcomes from pasture-scale management scenarios. Results: Cumulative overlap of species distributions revealed areas with greater potential community response to management. Within each species' potential regional-level distribution, the grassland bird community generally responded negatively to cropland cover and vegetation productivity at local scales (up to 10 km of survey sites). Multiple species declined with increasing bare ground and litter cover, shrub cover, and grass height measured within sites. Conclusions: We demonstrated a novel approach to multi-scale and multi-level prioritization for grassland bird conservation based on hierarchical community models and extensive population monitoring. Pasture-scale management scenarios also suggested the examined community may benefit from less bare ground cover and shorter grass height. Our approach could be extended to other bird guilds in this region and beyond. [ABSTRACT FROM AUTHOR]

Biodiversity monitoring is important as it allows to prioritize research into the causes of declines and assessing the efficacy of conservation measures. Regional assessments are valuable, because conservation policies and management are often implemented on national and sub-national level. We analyzed data from the German Common Bird Monitoring for 1990–2018. We derived indices of population size using standard log-linear models, based on point counts and route territory mapping at up to 1200 plots annually. We summarized species trends by ecological trait groups. Among the 93 common breeding birds, farmland birds declined strongly, birds of settlements declined. Forest birds initially declined, but recovered after ca. 2010. Wetland birds increased strongly, albeit the number of species with data was low. Consistent declines were found in ground-nesting birds, granivorous and invertebrate (other than insect)-feeding birds. Trends of insectivorous birds were stable on average, but farmland insectivores declined strongly since the year 2000. Long-distance migrants showed more negative trends compared to short-distance migrants and resident species. Species with narrow habitat niche declined disproportionally. Trends over the entire period were more negative in common species in the dataset (with a German breeding population of > 50 K and < 1 M pairs). On the opposite, short-term trends were more negative in less common species (< 50 K pairs). Cold-adapted species showed largely negative, warm-adapted largely positive trends. Multi-species indicators showed no directional change (i.e., a change from decline to increase or vice versa) conditional on the inclusion or omission of single species, but the magnitude of change was affected in groups with low sample size. This suggests that efforts should be made to develop robust monitoring schemes for rarer species that are not covered by the analyses here. We conclude that conservation policies in Germany should aim at halting the worrying declines in ground-nesting, often insectivorous, farmland birds. The recovery of forest and wetland birds is encouraging, but future trends need to be monitored. Ongoing climate change will affect species directly (via their thermal niche) and indirectly (e.g., through more forest disturbance). Conservation strategies will, therefore, need to consider species adaptation to environmental and climate change, e.g., in better protected area connectivity and management. [ABSTRACT FROM AUTHOR]

Can immigration save rural and small town America? Our goal is to highlight the new racial dynamics of population change in nonmetropolitan areas, where slowing population growth rates since 1990 eventuated in widespread depopulation during the post-2010 period. We use 3141 counties as the unit of analysis, tracking population change data over the 1990 to 2017 period. Our results, based on decennial census counts and population estimates from the U.S. Census Bureau, show that Hispanic population growth has been spatially ubiquitous, occurring in both declining and growing nonmetropolitan counties. Hispanic growth has slowed but not reversed chronic declines in rural population. Significantly, the growth of Latinos benefited a majority of historically depopulating or declining nonmetropolitan counties as well as nonmetropolitan counties that have continued to grow. Our analyses also reveal substantial heterogeneity in patterns of population change in nonmetropolitan America. Latino population growth often makes the difference between overall county population growth and decline. Nearly 200 nonmetropolitan counties grew during the 2010–2017 period, but only because Hispanic population increases offset non-Hispanic population declines. For these counties, which account for about 10 percent of all nonmetropolitan counties, Latinos clearly provided a demographic lifeline. Hispanics population gains were usually insufficient to reverse population declines in historically depopulating counties but nevertheless slowed the pace of decline. Hispanic growth was greatest in counties where the population was growing, resulting in a demographic multiplier effect. [ABSTRACT FROM AUTHOR]

Mercury is a global pollutant that has been widely shown to adversely affect reproduction and other endpoints related to fitness and health in birds, but almost nothing is known about its effects on migration relative to other life cycle processes. Here I consider the physiological and histological effects that mercury is known to have on non-migrating birds and non-avian vertebrates to identify potential mechanisms by which mercury might hinder migration performance. I posit that the broad ability of mercury to inactivate enzymes and compromise the function of other proteins is a single mechanism by which mercury has strong potential to disrupt many of the physiological processes that make long-distance migration possible. In just this way alone, there is reason to expect mercury to interfere with navigation, flight endurance, oxidative balance, and stopover refueling. Navigation and flight could be further affected by neurotoxic effects of mercury on the brain regions that process geomagnetic information from the visual system and control biomechanics, respectively. Interference with photochemical reactions in the retina and decreases in scotopic vision sensitivity caused by mercury also have the potential to disrupt visual-based magnetic navigation. Finally, migration performance and possibly survival might be limited by the immunosuppressive effects of mercury on birds at a time when exposure to novel pathogens and parasites is great. I conclude that mercury pollution is likely to be further challenging what is already often the most difficult and perilous phase of a migratory bird's annual cycle, potentially contributing to global declines in migratory bird populations. [ABSTRACT FROM AUTHOR]

The Common Crane (Grus grus) population has experienced an unprecedented increase across Europe during the last decades. Although cranes feed mostly on invertebrates, amphibians and berries during the breeding season, they can also eat eggs and young of other birds. Therefore, conservationists have raised concerns about the potential predatory effect of cranes on wetland avifauna, but the effects of crane predation on bird numbers have so far not been investigated. We here test the relationship between the crane and peatland bird population' abundances in Finland for five common wader and passerine species, and a set of seven less common waders, using line-transect data spanning from 1987 to 2014. We found that the population densities of two small passerines (Meadow Pipit Anthus pratensis and Western Yellow Wagtail Motacilla flava) and one wader species (Wood Sandpiper Tringa glareola) were positively associated with crane numbers, probably related to a protective effect against nest predators. For the two other common species and the set of less common waders, we did not find any significant relationships with crane abundance. None of the species was influenced by the (lagged) effect of crane presence (i.e. years since crane was first observed). Peatland drainage was responsible for most species' negative densities, indicating the need to protect and restore peatlands to mitigate the loss of peatland bird diversity in Finland. In addition, openness, wetness and area size were important peatland characteristics positively influencing most of the studied bird populations. The development in crane and other mire bird numbers in Europe should be monitored regularly to reveal any possible future predatory effects contributing to the shaping of the peatland bird community. [ABSTRACT FROM AUTHOR]

Increasing population and food demand has led to steadily declining resources as a result of over-exploitation and fossil fuel consumption that cause air contamination and reduce soil fertility. Therefore, this study aimed to investigate the correlation between air pollution, energy consumption, and the contribution of agriculture to national GDP. Secondary study data covering two decades were collected from different sources, and an autoregressive distributed lag (ARDL) bounds testing model was employed to determine long-run and short-run correlations. First, the unit root test was used to determine the stationarity of variables, and results showed that variables were integrated at level, ARDL co-integration equation estimation, which rejected the null hypothesis at less than 5% significance level. Further, based on the results of the ARDL bounds testing model, F-statistic values exceeded the upper bound value. This entire model was adjusted at a speed of −2.364 towards long-run equilibrium. In addition, CUSUM test and CUSUMSQ test results confirmed the goodness of fit of this model. In light of the resulting policy implications, the Chinese government may consider measures to improve the agricultural industry to meet the food demand for the fast-growing population while maintaining a healthy environment and safeguarding the available limited resources for future generations. [ABSTRACT FROM AUTHOR]

Monarch butterfly (Danaus plexippus L.) migratory populations in North America have declined over the last 20 years. Milkweed (Asclepias, Apocynaceae) is the primary larval host plant for monarchs. The primary conservation strategy for monarchs has been to build habitat, with a focus on milkweed seeds and plugs. However, not all milkweed may offer the same benefits for monarch conservation, as monarchs may prefer some taxa over others, or taxa may vary in the nutrients and protective toxins they provide. Comparisons of milkweed suitability have been made for milkweed taxa in the midwestern and eastern United States (U.S.), but very little is known about milkweeds found in the southwestern U.S. We tested female egg-laying preferences and larval performance in captivity on two species of milkweed commonly available for habitat plantings in the Southwest: Arizona milkweed (Asclepias angustifolia Schweig.) and pineneedle milkweed (A. linaria Cav.). We tested four measures of larval performance: survival, duration, mass and adult forewing length. Monarchs were more likely to lay eggs on Arizona milkweed than pineneedle milkweed. Larvae had a higher survival rate and grew more rapidly on Arizona milkweed, and adults from larvae raised on Arizona milkweed were larger than those raised on pineneedle milkweed. In the field, monarch caterpillars were more likely to be found on Arizona milkweed. We recommend Arizona milkweed for monarch habitat conservation projects in the Southwest within the natural range of Arizona milkweed, but that D. plexippus preference and performance be tested for additional western milkweed species. [ABSTRACT FROM AUTHOR]

Discharges of untreated effluent from fish farming into the aquatic environment are a practice that can affect local biodiversity. This study was conducted to characterize, in the Ebrie Lagoon, the structure of benthic macroinvertebrates inhabiting an environment exposed to effluent discharges from fish farms. The benthic macroinvertebrates were collected with a Van Veen grab seasonally between August 2016 and July 2017 at the effluent discharge point in the lagoon and at a reference station out of anthropogenic activities. Identification of organisms was done using specialized keys. The results revealed that the proportion of tolerant macroinvertebrates is relatively high (47.74%) at the point of discharge of fish farming effluents into the Ebrie Lagoon. While at the reference station, macroinvertebrates population is dominated by sensitive and medium-sensitive taxa (93.53%). The benthic macroinvertebrates population, influenced by seasonal variations, exhibits peaks of abundance and diversity during the rainy seasons, while during the dry seasons, they strongly decline. Fish farming effluents dumped in Ebrie Lagoon lead to structural modifications of the local benthic macroinvertebrates population. These disturbances are intensified in dry seasons and attenuated in rainy seasons. This information should be taken into account in any decision to promote the responsible practice of fish farming and the sustainable management of water resources exploited for fish farming purposes. [ABSTRACT FROM AUTHOR]

Japanese eel (Anguilla japonica) is a commercially important species; however, its population has declined in recent years. Appropriate conservation management, including habitat protection, is required to reverse this decline. However, their habitat use pattern during the riverine life stage is poorly understood. In this study, we investigated the longitudinal distribution and microhabitat of small-sized (<200 mm total length) and large-sized (≥200 mm total length) Japanese eels observed in 83 and 124 quadrats (1 m × 1 m), respectively, placed at seven stations in the Nikkeshi River in Fukushima Prefecture, Japan. Analysis using generalized linear models revealed that the eel density of both size classes decreased with increasing distance from the river mouth. In addition, the density of small-sized eels, but not large-sized ones, decreased as weir numbers increased. Moreover, analysis using generalized additive models showed that microhabitat uses differed between the size classes. The small-sized eels used near-shore habitats which had low current velocities. Their preferred habitats contained both complex substrates with smaller particle sizes and simple substrates with relatively large particle sizes. In contrast, the large-sized eels used both near-shore habitats with lower current velocities and the center of the river which had high current velocities. They preferred simple riverbed habitats with large particle-sized substrates and no underwater vegetation. These results suggest that there is a size-dependent change in the longitudinal distribution and microhabitat use of Japanese eels during their river life stage. These findings provide valuable information for the conservation and management of Japanese eels in rivers. [ABSTRACT FROM AUTHOR]

Bats are important wildlife to their ecologic system, but they are also a zoonotic disease reservoir. Close bat–human interaction can lead to pathogen spillover. We conducted a qualitative study in two districts of Bangladesh and interviewed 30 bat hunters who hunt bats primarily for consumption, to understand the process and their reasons for hunting bats and their perceptions about bats and bat-borne disease. Most hunters catch bats during winter nights, using a net. Bat meat is used for household consumption, and the surplus is sold to cover household expenditures. They prepare the bat meat at home to sell it in their own and in neighboring communities. They also sell live bats to traditional healers. They report that the bat population has declined compared with 5 or 10 years ago, a decline they attribute to hunting and deforestation. Many have heard of a disease from bat-contaminated date palm sap but do not believe that bats can spread such disease to humans. Close bat–human interaction reported in this study pose a risk of pathogen spillover. Conservation initiatives have the potential to reduce such interaction and so both reduce disease risk and support the ecology. [ABSTRACT FROM AUTHOR]

The plasticity in the trophic ecology, the breeding phenology, and the low nesting site fidelity would be the reasons why most of the gentoo penguin (Pygoscelis papua) populations breeding in the western Antarctic Peninsula and islands of Scotia Arc remained stable or increasing, despite the changing environmental conditions. Regardless of the overall trend, recent studies revealed a decline in the abundance of some gentoo penguin populations at those regions. Therefore, it is highly valuable to update the population size of each colony in order to confirm the current trends of individual colonies and generate a comprehensive overview of the population status. We report the abundance and breeding performance of gentoo penguins at the Stranger Point/Cabo Funes colony from 2000/2001 to 2018/2019. During the last season, 5383 breeding pairs and 5545 chicks in crèche were counted. Despite there were considerable inter-annual fluctuations over the study period, the total number of gentoo penguin breeding pairs increased by 74.6% (+ 3.1% per annum), while the number of chicks crèched increased by 60.0% (+ 2.6% per annum). However, the index of breeding success remained relatively constant over time, varying between 0.74 and 1.23 chicks in crèche/breeding pairs. Gentoo penguins have life-history strategies that are advantageous to face the environmental variability, allowing the species to maintain their breeding performance stable over time and enhance their resilience, which can favour the population growth at Stranger Point. [ABSTRACT FROM AUTHOR]

In contrast to the rapidly growing body of knowledge on migratory routes, wintering grounds and timing of annual life cycle events of migratory birds, knowledge on how migratory songbirds refuel at stopover sites along the Asian–Australasian flyway has increased only slowly, despite the fact that migrant birds show declining trends along it. We analysed the amount and variation of energy stores between species, variation of energy stores within the day and within the season, and estimated flight ranges of ten closely related warbler species (genera Acrocephalus, Arundinax, Locustella and Phylloscopus), captured at a stopover site in the Russian Far East during the autumn migration. We found significant differences in the species' energy stores, with Pallas's Leaf Warbler Phylloscopus proregulus having by far the highest. All species increased their energy stores within the day, and eight species increased their energy stores within the season. Individuals with the highest estimated flight ranges were able to cover a distance of 470 km during one nocturnal flight bout, which would have resulted in a minimum of nine stopovers before the birds reached their wintering grounds. We assume that a combination of factors determines the variation in energy stores between these species. We discuss the potential for these birds to exploit different habitats and refuelling strategies according to the distribution of species-specific refuelling habitats, and a variety of food resources, along the migratory route. This study is the first to provide information on energy stores, refuelling strategies and flight ranges for a set of closely related songbird species migrating along the Asian–Australasian flyway. [ABSTRACT FROM AUTHOR]

Abstract—This paper considers the dynamics of bird communities in agricultural landscapes of the Trans-Urals steppe from the period of heavy agricultural intensification (1988–1992) until the decline of agricultural production (2000–2008). In the conditions of intensive agriculture, the agrophytocenosis structure and features of the agricultural cultivation technology serve as key factors for the differentiation of bird communities in the steppe agricultural landscape. A relatively high specific richness characterizes bird communities of virgin pastures, while among field agrocenoses, i.e., in the areas seeded with perennial grass, the population is much poorer in the grain fields, which are prevalent in the area of agricultural landscapes and, especially, in fields of cultivated crops. During the period of agricultural stability, both the living conditions and the bird community structure in the agricultural landscape remained relatively constant from year to year. The economic crisis that took place at the end of the 20th century caused a deep decline in agricultural production, namely, a decrease in livestock and a reduction in the area of land sown. The restorative successions of vegetation in pastures and fallow lands led to significant changes in the conditions of bird habitats. For many species these changes meant an increase in the ecological capacity of the environment and contributed to the growth of their populations in the agricultural landscape (Alauda arvensis Linnaeus, 1758; Motacilla flava Linnaeus, 1758; Coturnix coturnix (Linnaeus, 1758); Tetrax tetrax (Linnaeus, 1758), etc.). The opposite tendency for reduction in numbers is demonstrated by species that avoid high closed grass stands (Melanocorypha leucoptera (Pallas, 1811), Oenanthe oenanthe (Linnaeus, 1758), and O. isabellina (Temminck, 1820), etc.). In general, the community density in the agricultural landscape increased by 2.3 times as compared to the precrisis period, and the number of nesting species increased by 1.3 times. For the species that had formed strong ecological connections with agriculture (primarily, the Corvidae family Рiса рiсa (Linnaeus, 1758); Corvus monedula Linnaeus, 1758; C. frugilegus Linnaeus, 1758; C. cornix Linnaeus, 1758), the decline in the agricultural production and the reduction of functioning agrocenoses had opposite consequences and caused the decline in their numbers in the agricultural landscape. [ABSTRACT FROM AUTHOR]

Abstract—The results of our bird counts carried out in 1996–2017 in inner mountain and high-mountain Dagestan are analyzed. The bird specific composition, average population abundance, and ecological structure of the avifauna in two difficult-to-reach mountain areas of the republic are described for the first time. Using cluster analysis, it is established that the avifauna patterns of most of the key areas are not only similar but are also unique because of the high heterogeneity of these habitats and, correspondingly, the faunal differences formed in the mountains under insufficient (inner mountain province) and sufficient (high-mountain province) moisture. Specific features of the avifauna in the studied areas are assumed to be created not only by residential communities of typical mountain birds, but also by adapted populations of migratory birds of plains nesting in the mountains. Analysis of our collected material gives a clear view of the species diversity and territorial distribution of the birds as well as of the avifauna resources of the inner mountain and high-mountain Dagestan. [ABSTRACT FROM AUTHOR]

Long-tailed Ducks (Clangula hyemalis) breed around lakes in tundra vegetation and spend their winter at sea. Their most important wintering site in Europe is the Baltic Sea, and most of the birds wintering there breed in northern Russia. In light of recent population declines, particularly of the Baltic Sea wintering population, it is important to gather all available information for this species to better understand their life history, and to pinpoint the primary threats leading to their decline. Because non-English literature is often neglected, we compiled a review of the information collected in 101 Russian scientific articles published between 1895 and 2017 relevant to Long-tailed Ducks inhabiting the European part of Russia (from Pskov Lake to Yugor Peninsula). We focused on their distribution, breeding densities as well as breeding and feeding biology. The data overall show a similar breeding biology and timing compared to the Asian part of the breeding range. However, due to limitations of the geographical and temporal scope of the reviewed studies, recent trends cannot be detected. Therefore, comprehensive studies are required to understand the contribution of changes in the breeding grounds to population declines observed in the wintering grounds. The data summarized here can provide a basis for such studies, including repeat surveys that will help to understand population trends. [ABSTRACT FROM AUTHOR]

Context: Islands harbor unique and sensitive wildlife. Little is currently known, however, on how touristic development affects island species. We analyzed how tourism-associated infrastructure impacts wildlife and habitat availability across a representative Mediterranean island landscape (Naxos, Aegean Sea, Greece). Objectives: First, we aimed to quantify how human-built structures (buildings and roads) affect island bird and reptile populations. Additionally, we investigated whether specific factors associated with this development such as cats, water, and food shape these impacts. Second, we mapped and quantified how touristic-dominated development over 33 years has changed landscape habitat availability for wildlife. Methods: We used wildlife field surveys and analyses to elucidate the spatial responses of wildlife to development, and combined this with a compilation of image-derived spatial data of the recent infrastructure expansion. Results: Native birds declined strongly close to buildings and roads, and were replaced there by non-native invasive species. Reptiles also largely disappeared close to human development; appearing to be influenced by predation by pet cats. Over the study period, 1982–2015, human-built structures nearly doubled. Combining the increase in infrastructure numbers with each structure's estimated ecological footprint, 100 m, revealed that only 20.5% of the potential wildlife habitat remains unaffected by development in the study region. Conclusions: This study demonstrates the landscape-level effects of diffuse tourism-dominated development on island wildlife and suggests the existence of cooperative effects between touristic expansion and exotic species. Given the pervasive presence of tourism in island habitats, it raises concerns about its effects on resident biodiversity. [ABSTRACT FROM AUTHOR]

Accurately detecting the magnitude and direction of population trends provides essential information for conservation management. There are numerous local and international long-term waterbird monitoring programmes with substantial variation in how frequently surveys are conducted. We aimed to assess how temporal frequency of waterbird surveys influence three aspects of population trends: (1) level of uncertainty around estimates of long-term trends; (2) frequency, duration and overlap of significant short-term increases or declines in trend trajectory; and (3) differences between estimated change in population size measured over four different time periods. Data from 28 years of surveys at a waste water treatment facility in South Africa were used to model the population trend of 41 waterbird species. We used generalised additive mixed-models to compare significance and magnitude of population change trends between monthly and biannual surveys. Direction and shape of species trends were similar between protocols although uncertainty around trends was generally lower when monthly data were used. The number of significant trend trajectories, the majority of which were declines, was higher in monthly models. Temporal overlap of periods of significant change of trends of the two protocols averaged 30%. However, both sampling protocols offered similar conclusions about long-term change in population size of species. General patterns differed conspicuously among species, although groups of species showed similar trajectories of population change. We conclude that biannual surveys are appropriate if the goal is to assess general patterns of population change. However, if management action relies on understanding the significance of population trajectories, surveys at a finer temporal scale are required, especially for species showing a pattern of unpredictable movement. Trade-offs between logistical constraints and statistical rigour as well as species identity need to be carefully considered for the design of long-term monitoring programmes of waterbirds. [ABSTRACT FROM AUTHOR]

Urbanization is an inevitable process in human civilization. When populations expand, socio-economic and political dynamics typically shift from agricultural predominance to one of industry and services. Accordingly, agrarian societies transform from diffuse rural communities to dense urban centers. By 2050, the world's population is projected to reach 9.1 billion, with the urban population growing from 50 to 70%. Inevitably, this ever-expanding urban frontier encroaches along the human-ecological interface, creating a challenge for conservation and biodiversity. For the past 30 years, agricultural cropland area in the USA has remained fairly constant, despite significant population growth over the same time period. Thus, agricultural production in America has more than kept pace with rapid population growth and global export demand without increasing the farmland footprint at the expense of wildlife habitat. This is primarily due to considerable advances made in pesticide development, safety, and regulation, coupled with soil conservation and genetically modified crops. Still, the potential contribution of agriculture to ecosystem impairment remains contentious, particularly with regard to current use of pesticides. Recently, significant focus has been placed on the state of bird populations in the USA. Many species are considered imperiled, and this is often attributed in the popular media to pesticide use. However, focusing solely on the agricultural/chemical story as a significant driver of species viability and ecological risk within the broader biodiversity and conservation narrative lacks context and perspective. Moreover, the hypothesis that pesticides are indirectly affecting bird population status via reductions in food resources should be considered with caution and within the context of other likely causes. This work explores the dynamics between historical land use, human-controlled activity, and bird population trends from a holistic perspective within the USA. The aim is to provide context, developed from a relative comparison of potential contributing factors, in order to help inform discussion and foster dialogue between industry, academia, government, non-governmental organizations, and the public. [ABSTRACT FROM AUTHOR]

Tropical understory birds have declined due largely to habitat loss and fragmentation. Here, we revisited a study conducted three decades ago and used artificial nests to examine depredation rates in a Costa Rican biological corridor. Using camera trap data, we compared potential nest predator detection rates at experimental tinamou ground nests in La Selva Biological Station and at sites in five local forest fragments. Nest predator detections were positively associated with landscape-scale core forest and distance away from forest edge, as well as with local-scale human trails, and negatively associated with primary forest compared to secondary growth. Twenty-two of 52 artificial nests were depredated, which was similar to previous research in the area. Mammalian and avian predators were common nest predators, but unknown predators (presumably snakes) were responsible for half of nests lost. Nests within La Selva core forest had lower probability of nest loss compared to fragments despite exhibiting higher predator detection rates. Yet other fragmentation covariates such as distance from forest edge, nest occurrence on human trails, or forest age were not associated with nest loss. We suggest that concentrated foraging is the underlying mechanism behind the community interactions that we observed. Community members exist in concentrated use areas within forest fragments, which results in heightened predator foraging rates and thus stronger interactions in fragments despite more predators encountering the nests in core forest. Fragmentation is a global phenomenon and we suspect that concentrated community use of limited resources is driving species to interact more strongly than in natural ecosystems. [ABSTRACT FROM AUTHOR]

Ponds—small, isolated freshwater bodies—have vanished in large numbers during the last decades. Despite such great loss, the number of natural small water bodies has still remained quite high in Estonia. Nevertheless, many pond-related species, including amphibians such as the northern crested newt Triturus cristatus and the common spadefoot toad Pelobates fuscus—are in decline in Estonia, suggesting that the conditions of extant natural ponds might not be optimal. However, these conditions have never been examined. To halt the decline of these two pond-breeding species, more than 400 ponds have been constructed or restored from 2004 to 2014 in Estonia. In this study we compared 85 natural and 85 constructed ponds (which were created or restored especially for T. cristatus and/or P. fuscus) to find out: (i) what the main differences are between natural ponds and ponds specially created for threatened species; (ii) whether natural ponds provide breeding conditions for local amphibians; (iii) given the decline of T. cristatus and P. fuscus, what are the characteristics lacking in natural ponds, due to which they are not providing quality breeding habitats for these species. Whereas the constructed ponds were located in open habitats with mineral soils, the natural ponds were mainly in mires and forests, being thus more shaded. Amphibian diversity was higher in the constructed ponds and was positively related to the depth of the pond, the clarity of the water, the presence of slanting slopes, the absence of fish and the presence of nearby fields. T. cristatus preferred constructed ponds for reproduction, while the breeding site selection of P. fuscus was determined mainly by terrestrial habitat characteristics. Importantly, when the threatened species were removed from the sample, the diversity of common amphibians did not differ between natural and constructed ponds, suggesting that in our study sites natural water bodies act still as breeding sites for common species, but not for threatened ones. We conclude that pond construction is an important tool to halt the decline of threatened species, even in landscapes where natural ponds are still preserved. [ABSTRACT FROM AUTHOR]