City Is Less Risky For House Sparrows Infection

Urbanization affects the ecology of wildlife diseases and although it has been suggested that there are lower risks of infection in urban areas, there have been no experiments to support this conclusion. We assessed haemosporidian prevalence and intensity in House Sparrows Passer domesticus using field and experimental data under contrasting conditions (i.e. urban vs. non-urban). For experimental data, we kept 32 male House Sparrows in captivity as a proxy of stress, and for field data we sampled 49 House Sparrows (17 females). We made use of microscopy to determine the relative intensity and used the polymerase chain reaction to estimate infection prevalence. We obtained total leucocyte counts, leucocyte differentials, heterophil/lymphocyte ratio (H/L) as a measure of stress, and the Polychromatic Index as a measure of physiological condition (erythropoiesis). We identified a total of 10 haemosporidian lineages. For field samples (both males and females), we found a significantly higher prevalence of infection in non-urban House Sparrows than in urban ones. Under experimental conditions, non-urban House Sparrows showed a higher prevalence than urban ones both before and after captivity, with a significant increase in parasite intensity. The number of infected birds increased after captivity for both urban (~ 32%) and non-urban House Sparrows (~ 19%), indicating either a recrudescence of chronic and relapses of latent infections or the appearance of infections that had been acquired earlier. The H/L ratio was significantly higher for non-urban than for urban male House Sparrows before captivity. No difference in H/L was found for urban House Sparrows before and after captivity, indicating tolerance to city stressors. Our results showed a significant decrease in H/L for non-urban birds after captivity, suggesting higher stress in the non-urban agricultural environment. Haemosporidian infections were not associated with the H/L ratio. Our study provides evidence that highly urbanized areas within cities represent lower haemosporidian infection risks than do non-urban areas for House Sparrows.

Santiago-Alarcon D, Carbó-Ramírez P, MacGregor-Fors I., Chávez-Zichinelli C.A., Yeh P.J. 2020. Avian malaria prevalence of an invasive urban bird is lower in urban than non-urban environments. Ibis162: 201-214. doi:10.1111/ibi.12699

The City Choir Is Out of Tune!

Living in the city represents a great challenge for organisms that are exposed to the novel environmental conditions inherent to urbanization. Recent studies have highlighted the ecological impact that urbanization poses on the acoustic phenotype and singing routines of birds. However, the organization and structure of avian dawn choruses in urban settings remains largely unexplored. In this study, we assessed the temporal structure of avian dawn choruses in an intra-urban area and a peri-urban forest using bipartite network analyses. We predicted a random network structuring of dawn choruses across time at the intra-urban area, while expected a non-random structure (i.e., modular or nested) at the peri-urban forest. While we detected different groups of birds vocalizing

together temporarily, following a modular pattern in both studied conditions, only the one from the peri-urban forest showed a sequential temporal structure of dawn choruses. Avian dawn choruses from both intra-urban and peri-urban areas were mainly comprised by phylogenetically unrelated species (i.e., random phylogenetic structure), also exhibiting low overlap on singing frequencies. Our results are in agreement with the temporal partitioning of the acoustic space in the peri-urban forest. Our findings also suggest that the absence of temporally-structured modules of bird dawn choruses at heavily-urbanized areas could be related to the depauperization of the avian community at intra-urban areas as a sequel of ecological filtering, as well as the consequent importance of the dominance of the acoustic space by invasive species.

Marín-Gómez OH, Dáttilo W, Sosa-López JR, Santiago-Alarcon D, MacGregor-Fors I. 2020. Where has the city choir gone? Loss of the temporal structure of bird dawn choruses in urban areas. Landscape and Urban Planing 194:103665

How do Diptera vectors respond to habitat structure and haemosporidian infection risk?

The presence of insect vectors is a key prerequisite for transmission of vector-borne disease such as avian haemosporidians. In general, the effects of land use change on Diptera vectors are not well studied; the response of vectors to forest management depends on vector species, as has been shown previously for the birds. We tested if abundance of insects from different Diptera families and haemosporidian infection are affected through alteration of habitat structural variables (measured by LiDAR) and forest management intensities. We identified higher large-scale variation of female insect abundance in northeastern than in southwestern Germany. Unmanaged forest stands had higher Diptera insect abundances. We found that abundance of female Diptera increased with the amount of forest gaps but decreased in forest plots with more south facing aspect, higher habitat structural heterogeneity, temperature and humidity. We found that haemosporidian infections in Diptera insects increased with increased management intensity and more canopy structural diversity (e.g., amount of edge habitat), but decreased with a denser shrub layer, deeper leaf litter and higher humidity (characteristics for unmanaged forest stands). Although higher forest management intensity decreased vector abundance, the haemosporidian infections in the vectors increased, indicating a significant effect of forest management on disease dynamics.

van Hoesel W, Marzal A, Magallanes S, Santiago-Alarcon D, Ibáñez-Bernal S, Renner SC. 2019. Management of ecosystems alters vector dynamics and haemosporidian infections. Scientific Reports9:8779. https://doi.org/10.1038/s41598-019-45068-4 

Avian Biogeography Across Neotropical Seasonal Dry Forests

Neotropical seasonally dry forests (NSDF) are widely distributed across Latin America and the Caribbean. They possess important levels of species richness and endemism but few studies have assessed the diversity patterns and ecological relationships between the entire avifauna of these threatened forests. Thus, in order to analyse the macro-ecological patterns and the community structure of NSDF avifaunas, we generated species distribution models describing the current geographical distribution of 1,298 bird species inhabiting NSDF. We assessed species richness gradients in terms of distance from the Equator using both linear and polynomial regressions. Then, based on a matrix composed of the presence or absence of species in 563 quadrants, we performed cluster analyses to identify the main NSDF regions and describe the avifaunal affinities among them. For the identified groups, we estimated the dissimilarity values, using both an ANOSIM test and the βSIM index. Overall, we observed the lack of an equatorial peak for species diversity of NSDF avifauna in the latitudinal gradient and identified 12 avifaunistic groups. The βSIM index among the NSDF avifaunal groups ranged from 0.05-0.73, showing statistically significant differences (R = 0.894, p = 0.001) in species composition among them. Species shared between two or three NSDF groups comprised a higher proportion (~38%) than those exclusive to each group (~23%). Only 35 species were shared between the 12 groups. This information supports a separation of the NSDF avifauna into two major groups (northern and southern), as well as the idea of connections during recent geological time among the NSDF in southeastern South America (the so-called Pleistocene Arc Hypothesis). We provide a scientific framework to contextualise the importance of each NSDF nuclei in terms of their avifauna, supplying an ecological basis for future conservation decisions in order to protect their diversity.

Prieto-Torres, D.A., Rojas-Soto, O.R., Santiago-Alarcon, D., Bonaccorso, E. & Navarro-Sigüenza, A.G. (2019). Diversity, endemism, species turnover and relationships among avifauna of neotropical seasonally dry forests. Ardeola, 66: 257-277.

Spatiotemporal Bird-Haemosporidian Analysis of an Urban Bird Assemblage

Prevalence responses to anthropic factors differ across hosts and parasite species. We here analyzed the spatiotemporal variation of avian haemosporidian prevalence in bird assemblages of the Mooswald forest (i.e., urban greenspace; Freiburg, Germany), in response to local environmental features (e.g., water sources, human presence (visited)/absence (unvisited)) and bird-level traits (e.g., body condition, age, sex) in 2 years. We analyzed a total of 544 samples of seven bird species. Haemosporidian prevalence was significantly different between some focal bird species. There was a negative association between distance to the nearest water source and prevalence in the year 2011, and the opposite pattern for the year 2013. However, when analyzed for the six focal species separately, such a relationship could change from a negative to a positive one, or there could be no relationship at all. For Leucocytozoon there was higher prevalence in the section of the forest visited by humans. We did not find spatial autocorrelation for prevalence across the study site, but there were statistically significant local spatial clusters in the visited section. Although there were similar responses of prevalence to some factors, infection patterns were generally bird species specific. Thus, prevalence is a labile epidemiological parameter, varying spatiotemporally in an idiosyncratic way.

International Journal for Parasitology 49 (2019) 235–246. You can download the paper from the following link during the next 50 days: https://authors.elsevier.com/a/1YkCD4j~kk0TK

First Morphological Phylogeny of Avian Haemosporidians (Editor´s Choice)

The traditional classification of avian Haemosporida is based mainly on morphology and life history traits. Recently, molecular hypotheses have challenged the traditional classification, leading to contradictory opinions on whether morphology is phylogenetically informative. However, the morphology has never been used to reconstruct the relationships within the group. We inferred the phylogeny of avian Haemosporida from 133 morphological characters present in blood stages. We included all species with at least one mitochondrial gene characterized (n = 93). In order to recover the evolutionary history and identify phylogenetically and taxonomically informative characters, they were mapped on the total evidence phylogeny. We identified a unique combination of morphological traits, clearly differentiating avian Haemosporida genera, sub-genera of Leucocytozoon and Haemoproteus, and some Plasmodium sub-genera. Plasmodium had the highest number of synapomorphies. Furthermore, 86% of the species presented a unique combination of taxonomically informative characters. The combination of morphology and mtDNA proved to be a robust alternative to reconstruct the relationships among avian Haemosporida, obtaining a resolution and support similar to that obtained using full mitochondrial genome sequences for over 100 lineages.

Citation: Hernández-Lara C, Espinosa de los Monteros A, Ibarra-Cerdeña CN, García-Feria L, Santiago-Alarcon D. 2018. Combining morphological and molecular data to reconstruct the phylogeny of avian Haemosporida. International Journal for Parasitology 48: 1137-1148

BIRD RICHNESS AND COMPOSITION AT DIFFERENT LAND USE TYPES

Studying the anthropogenic components of landscapes can provide a solid groundwork to better understand ecological patterns and processes. In this study, we assessed bird species richness and composition in 5 different environmental conditions (well-preserved cloud forest, peri-urban forest, urban greenspace, shade coffee plantation, and cattle ranch) embedded in a landscape whose original vegetation was tropical montane cloud forest. Our results showed that the most similar vegetation structure and physiognomy were peri-urban forest and shade coffee plantation, with urban

greenspaces comprising a highly different condition. Regarding species richness, we found no differences for the nonbreeding season (average values 32.9–41.8), but we did find statistical differences for the breeding season (average values 24.5–43.7); highest species richness was recorded for well-preserved cloud forest (43.7 calculated species), which was significantly different from shade coffee plantation (lowest species richness value 24.5) and urban greenspaces (29 calculated species). These results support the idea that during the nonbreeding season, when habitat requirements are less strict, species distribute homogeneously across the landscape, whereas species tend to be more selective and concentrated in original forests during the breeding season. Community composition during the breeding season showed a .40% similarity cluster composed of well-preserved cloud forest, shade coffee plantation, and cattle ranch. In the nonbreeding season, however, 2 clusters were formed at ~30% similarity: (1) urban greenspaces and cattle ranch; and (2) peri-urban forest, shade coffee plantation, and well-preserved cloud forest. Our results highlight the overall negative effect of urbanization on breeding bird species richness and composition, as well as the importance of having large patches of well-preserved cloud forests in sheltering high bird diversity.

The Wilson Journal of Ornithology 130(1):81–93, 2018

URL: http://www.bioone.org/doi/full/10.1676/16-087.1