Use of Anthropogenic Nest Materials by Black-crested Titmice Along an Urban Gradient

Numerous avian species use anthropogenic materials in constructing nests, particularly in urbanized environments. Anthropogenic materials, including plastics, have been demonstrated to have both beneficial and harmful effects on survival and reproduction. During the spring of 2018, we collected 45 Black-crested Titmouse Baeolophus atricristatus nests in San Marcos, TX, U.S. with two objectives: 1) assess and compare the mass and proportion of nest materials along an urban gradient, and 2) examine the relationship between nest materials, clutch size, and hatching success. We categorized each nest based on collection location as either urban, residential, park or rural and separated nest materials into six categories: leaves, snakeskin, twigs, moss, plastic, and non-plastic artificial materials. We then compared raw mass and proportion of mass of each nest material among urbanization categories. Nests in the urban category were 1.6-1.9 times lighter in mass than nests in other locations along the urban gradient (p = 0.01) and contained 4-5 times greater proportion, but not mass, of plastic compared to nests in all other locations. Nests in residential areas contained the greatest mass of combined anthropogenic materials. Neither clutch size nor hatching success differed based on urbanization category, nest mass, or proportions of anthropogenic or natural nest materials. The differences in mass of nests and increased proportion of plastics could have been due to a lack of natural nesting materials however, we did not estimate availability of nesting materials at any location. Results add to the growing literature that the use of anthropogenic materials in nests varies across an urban gradient, and the effect of anthropogenic materials on nesting parameters varies among species.

Impact of Urbanization to an Island and the Continent: Species Turnover and Nestedness in Neotropical Bird Assemblages

Islands are well-known as particular and vulnerable ecosystems with evolutionary histories, environmental characteristics, and original communities different from those of continents. On the contrary, urban environments are recent, artificial, and structurally similar among distant regions. To assess the relative importance of regional and local processes on urban biota, we chose two urban environments, i.e., one on the mainland and another on an island in the same ecoregion. We asked whether the urbanization process affects the avian biodiversity of the ISLAND in the same way as in the continent. We defined an urban gradient with three levels of building density, namely, patches of native vegetation (remnant woodlands in the urban matrix), medium density urbanized areas that maintain vegetation along the streets and gardens, and residential areas with less vegetation cover and higher building density. In each geographical locality, we selected three sites (replicates) for each level of the urban gradient and did bird surveys. We found two times as many species in the urban landscape of the continent (69) as on the island (35), with the analogous richness decrease along the gradient in both regions. Species similarity was higher between urbanized sites of both regions compared with the similarity between woodlands and urbanized sites, showing that urban matrix filters similar species of each pool regionally. Individual species responded to urban structure in different ways. We found 32% of bird species were urban exploiters, 48% urban tolerant, and 20% urban avoiders in both regions. However, some species showed different frequencies of occurrence on the island and the continent. Species turnover contributed more than richness differences to species dissimilarity along the urban gradient on the continent. Contrarily, the nestedness component (i.e., species being a strict subset of the species at a richer site) was higher on the island. We concluded that the negative impact of highly urbanized areas on birds was stronger on the island than on the continent. Our results may help to assess the implications of beta-diversity loss, especially on islands.

Gut microbiome, enteric infections and child growth across a rural–urban gradient: protocol for the ECoMiD prospective cohort study

IntroductionThe functional consequences of the bacterial gut microbiome for child health are not well understood. Characteristics of the early child gut microbiome may influence the course of enteric infections, and enteric infections may change the composition of the gut microbiome, all of which may have long-term implications for child growth and development.Methods and analysisWe are conducting a community-based birth cohort study to examine interactions between gut microbiome conditions and enteric infections, and how environmental conditions affect the development of the gut microbiome. We will follow 360 newborns from 3 sites along a rural–urban gradient in northern coastal Ecuador, characterising enteric infections and gut microbial communities in the children every 3 to 6 months over their first 2 years of life. We will use longitudinal regression models to assess the correlation between environmental conditions and gut microbiome diversity and presence of specific taxa, controlling for factors that are known to be associated with the gut microbiome, such as diet. From 6 to 12 months of age, we will collect weekly stool samples to compare microbiome conditions in diarrhoea stools versus stools from healthy children prior to, during and after acute enteric infections, using principal-coordinate analysis and other multivariate statistical methods.Ethics and disseminationEthics approvals have been obtained from Emory University and the Universidad San Francisco de Quito institutional review boards. The findings will be disseminated through conference presentations and peer-reviewed journals.

Raptors of A Neotropical City: Diversity And Habitat Relationships Along An Urbanization Gradient

Urbanization involves changes in landscape terrain, hydrology, and vegetation. These changes allow some wildlife species to thrive in cities while blocking others. We analyzed how a gradient of urbanization in the city of Xalapa could have a filtering effect that prevents some raptors from occurring or effectively use the most urbanized areas, and where such filtering effects occur. We selected 6 habitat variables that could predict the detection and occupation of raptors along the urban gradient. We conducted direct observations and call-broadcast surveys to estimate relative abundance, richness, and diversity of raptors from June 2019–February 2020. We visited 20 sites during three seasons, from dawn–11:00 and 18:00–23:00 h. We obtained 201 individual records of 14 species. The best-preserved part of the gradient (< 7.7% urban cover) had the highest species diversity, while the 4th category along the gradient (53.9% urban cover) had the lowest, suggesting that at this level of urbanization an abrupt filtering effect occurs on the raptor community. The proportion of exotic/native plant species was the best detection predictor for most of the diurnal species and Ciccaba virgata. The proportion of urban relative to green area was negatively associated with the occupation of Accipiter cooperii and Rupornis magnirostris. Our results suggests that this Neotropical city effectively acts as a filter for most species, with only 4 raptors able to use or occupy most of the urban gradient. Our work represents a critical first step towards understanding how the process of urbanization influences a raptor community.

Reduced ectoparasite load, body mass and blood haemolysis in Eurasian kestrels (Falco tinnunculus) along an urban–rural gradient

Urbanisation is proceeding at an alarming rate which forces wildlife to either retreat from urban areas or cope with novel stressors linked to human presence and activities. For example, urban stressors like anthropogenic noise, artificial light at night and chemical pollution can have severe impacts on the physiology of wildlife (and humans), in particular the immune system and antioxidant defences. These physiological systems are important to combat and reduce the severity of parasitic infections, which are common among wild animals. One question that then arises is whether urban-dwelling animals, whose immune and antioxidant system are already challenged by the urban stressors, are more susceptible to parasitic infections. To assess this, we studied nestlings of Eurasian kestrels (Falco tinnunculus) in Vienna, Austria, during 2015 and 2017. We measured biomarkers of innate immune function, oxidative stress and body mass index and ectoparasite infection intensity in 143 nestlings (from 56 nests) along an urban gradient. Nestlings in more urbanised areas had overall fewer ectoparasites, lower haemolysis (complement activity) and lower body mass index compared to nestlings in less urbanised areas. None of the other immune or oxidative stress markers were associated with the urban gradient. Despite some non-significant results, our data still suggest that kestrel nestlings experience some level of reduced physiological health, perhaps as a consequence of exposure to more urban stressors or altered prey availability in inner-city districts even though they had an overall lower ectoparasite burden in these heavily urbanised areas.

Japanese Honeybees (Apis cerana japonica Radoszkowski, 1877) May Be Resilient to Land Use Change

Pollinators are being threatened globally by urbanisation and agricultural intensification, driven by a growing human population. Understanding these impacts on landscapes and pollinators is critical to ensuring a robust pollination system. Remote sensing data on land use attributes have previously linked honeybee nutrition to land use in the Western Honeybee (Apis mellifera L.). Here, we instead focus on the less commonly studied Apis cerana japonica—the Japanese Honeybee. Our study presents preliminary data comparing forage (honey and pollen) with land use across a rural-urban gradient from 22 sites in Kyushu, southern Japan. Honey samples were collected from hives between June 2018 and August 2019. Pollen were collected and biotyped from hives in urban and rural locations (n = 4). Previous studies of honey show substantial variation in monosaccharide content. Our analysis of A. cerana japonica honey found very little variation in glucose and fructose (which accounted for 97% of monosaccharides), despite substantial differences in surrounding forage composition. As expected, we observed temporal variation in pollen foraged by A. cerana japonica, likely dependent on flowering phenology. These preliminary results suggest that the forage and nutrition of A. cerana japonica may not be negatively affected by urban land use. This highlights the need for further comparative studies between A. cerana japonica and A. mellifera as it could suggest a resilience in pollinators foraging in their native range.

Japanese Honeybees (Apis Cerana Japonica Radoszkowski, 1877) May Be Resilient to Land Use Change

Pollinators are being threatened globally by urbanisation and agricultural intensification, driv-en by a growing human population. Understanding these impacts on landscapes and pollinators is critical to ensuring a robust pollination system. Remote sensing data on land use attributes have previously linked honeybee nutrition to land use in the Western Honeybee (Apis mellifera L.). Here, we instead focus on the less commonly studied Apis cerana japonica &ndash; the Japanese Honeybee. Our study presents preliminary data comparing forage (honey and pollen) with land use across a rural-urban gradient from 22 sites in Kyushu, southern Japan. Honey samples were collected from hives between June 2018 and August 2019. Pollen were collected and biotyped from hives in urban and rural locations (n = 4). Previous studies of honey show substantial vari-ation in monosaccharide content. Our analysis of A. cerana japonica honey found very little varia-tion in glucose and fructose (which accounted for 97% of monosaccharides), despite substantial differences in surrounding forage composition. As expected, we observed temporal variation in pollen foraged by A. cerana japonica, likely dependent on flowering phenology. These prelimi-nary results suggest that the forage and nutrition of A. cerana japonica may not be negatively af-fected by urban land use. This highlights the need for further comparative studies between A. cerana japonica and A. mellifera as it could suggest a resilience in pollinators foraging in their na-tive range.