Comparative range use by three Atlantic Forest understorey bird species in relation to forest fragmentation

Loss of forest cover and host functional diversity increases prevalence of avian malaria parasites in the Atlantic Forest

Host phylogenetic relatedness and ecological similarity are thought to contribute to parasite community assembly and infection rates. However, recent landscape level anthropogenic changes may disrupt host-parasite systems by impacting functional and phylogenetic diversity of host communities. We examined whether changes in host functional and phylogenetic diversity, forest cover, and minimum temperature influence the prevalence, diversity, and distributions of avian haemosporidian parasites (genera Haemoproteus and Plasmodium) across 18 avian communities in the Atlantic Forest. To explore spatial patterns in avian haemosporidian prevalence and taxonomic and phylogenetic diversity, we surveyed 2241 individuals belonging to 233 avian species across a deforestation gradient. Mean prevalence and parasite diversity varied considerably across avian communities and parasites responded differently to host attributes and anthropogenic changes. Avian malaria prevalence (termed herein as an infection caused by Plasmodium parasites) was higher in deforested sites, and both Plasmodium prevalence and taxonomic diversity were negatively related to host functional diversity. Increased diversity of avian hosts increased local taxonomic diversity of Plasmodium lineages but decreased phylogenetic diversity of this parasite genus. Temperature and host phylogenetic diversity did not influence prevalence and diversity of haemosporidian parasites. Variation in the diversity of avian host traits that promote parasite encounter and vector exposure (host functional diversity) partially explained the variation in avian malaria prevalence and diversity. Recent anthropogenic landscape transformation (reduced proportion of native forest cover) had a major influence on avian malaria occurrence across the Atlantic Forest. This suggests that, for Plasmodium, host phylogenetic diversity was not a biotic filter to parasite transmission as prevalence was largely explained by host ecological attributes and recent anthropogenic factors. Our results demonstrate that, similar to human malaria and other vector-transmitted pathogens, prevalence of avian malaria parasites will likely increase with deforestation.

Comparison between telemetry and spot-mapping to determine space use of the Kenyan endemic Hinde's babbler

Different methods to measure species behaviour and space use may produce diverging results, and provide advantages and shortcomings. Data from spot-mapping of animals might be affected from restricted detectability of individuals in dense vegetation, while radio-tracking provides a less biased (or even unbiased) measure of space use. Here we compare results from spot-mapping and telemetry of four family groups (i.e. five individuals belonging to these four family groups), respectively of the Kenyan endemic cooperative-breeding bird Hinde's babbler, Turdoides hindei. Data from spot-mapping showed that the space use of T. hindei is mostly restricted to riparian vegetation. Home-range sizes calculated from telemetry were five times larger if compared with data obtained from spot-mapping. Telemetry data showed that T. hindei also moves across agricultural land, and mean and maximum displacements are larger if compared with data obtained from spot-mapping. Several reasons might lead to these differences: (1) Telemetry data also consider rare long-distance excursions, while (2) observers of spot-mapping might fail to observe long-distance movements and thus underestimate home-range sizes as well as displacement distances; (3) results from telemetry might become blurred from measurement error during the triangulation of fixes. Our study confirms that both methods provide advantages, but also shortcomings, which need to be considered when selecting a method to elaborate a research question.

Does scale matter? The influence of three-level spatial scales on forest bird occurrence in a tropical landscape

Consequences of habitat fragmentation for species occurrence are amongst the most important issues in landscape and conservation ecology. Empirical and theoretical studies have demonstrated that the total amount of habitat, patch size and connectivity have nonlinear effects on species survival on multiple spatial and temporal scales. Therefore, population models need to incorporate multiple scales, which can be extremely valuable to prioritizing conservation efforts in these changing landscapes. We tested how the amount and configuration of habitat affect understory bird species occurrence using fine to broad-scale habitat features. We used playback to sample birds in 13 Atlantic Forest fragments in Southeast Brazil. Microhabitat, local and regional landscape variables were tested against bird occurrence. Our results demonstrate that different bird species respond to different habitat scales. Sclerurus scansor, Xiphorhynchus fuscus, Automolus leucophthalmus, Drymophila ochropyga, Mackenziaena leachii, and Chiroxiphia caudata were most influenced by tree height and diameter (microhabitat characteristics), S. scansor, F. serrana and Pyriglena leucoptera were most influenced by forest cover and red-edge reflectance(local-scale metrics) and S. scansor, X. fuscus, D. ochropyga, P. leucoptera, F. serrana and M. leachii had area, core area and functional connectivity index (landscape features) as stronger predictors of species occurrence. Small forest fragments acted as corridors and increased overall connectivity of the entire community. The most effective means of maintaining long-term population connectivity of understory birds involves retaining both large and small areas, including forests with different micro-habitat characteristics. No management approach based on a single-scale would benefit all species. Implementing multiscale conservation strategies are necessary for maintaining long-term viability of forest birds on tropical landscapes.

High Emigration Propensity and Low Mortality on Transfer Drives Female-Biased Dispersal of Pyriglena leucoptera in Fragmented Landscapes

Dispersal is a biological process performed in three stages: emigration, transfer and immigration. Intra-specific variation on dispersal behavior, such as sex-bias, is very common in nature, particularly in birds and mammals. However, dispersal is difficult to measure in the field and many hypotheses concerning the causes of sex-biased dispersal remain without empirical confirmation. An important limitation of most empirical studies is that inferences about sex-biased dispersal are based only on emigration proneness or immigration success data. Thus, we still do not know whether sex-biased immigration in fragmented landscapes occurs during emigration, transfer or in both stages. We conducted translocation and radiotracking experiments to assess i) whether inter-patch dispersal movements of a rainforest bird (Pyriglena leucoptera) is sex-biased and ii) how dispersal stages and the perceptual range of the individuals are integrated to generate dispersal patterns. Our results showed that inter-patch dispersal is sex-biased at all stages for P. leucoptera, as females not only exhibit a higher emigration propensity but are subjected to a lower risk of predation when moving through the matrix. Moreover, our data support a perceptual range of 80 m and our results showed that dispersal success decreases considerably when inter-patch distances exceeds this perceptual range. In this case, birds have a higher probability of travelling over longer routes and, as a consequence, the risk of predation increases, specially for males. Overall, results supported that assuming dispersal as a single-stage process to describe dispersal behavior may be misleading. In this way, our study advanced our understanding of processes and patterns related to inter-patch dispersal of neotropical forest birds, shedding light on potential implications for population dynamics and for the management of fragmented landscapes.

Contrasting Patterns of Species Richness and Functional Diversity in Bird Communities of East African Cloud Forest Fragments

Rapid fragmentation and degradation of large undisturbed habitats constitute major threats to biodiversity. Several studies have shown that populations in small and highly isolated habitat patches are prone to strong environmental and demographic stochasticity and increased risk of extinction. Based on community assembly theory, we predict recent rapid forest fragmentation to cause a decline in species and functional guild richness of forest birds combined with a high species turnover among habitat patches, and well defined dominance structures, if competition is the major driver of community assembly. To test these predictions, we analysed species co-occurrence, nestedness, and competitive strength to infer effects of interspecific competition, habitat structure, and species' traits on the assembly of bird species communities from 12 cloud forest fragments in southern Kenya. Our results do not point to a single ecological driver of variation in species composition. Interspecific competition does not appear to be a major driver of species segregation in small forest patches, while its relative importance appears to be higher in larger ones, which may be indicative for a generic shift from competition-dominated to colonisation-driven community structure with decreasing fragment size. Functional trait diversity was independent of fragment size after controlling for species richness. As fragmentation effects vary among feeding guilds and habitat generalists, in particular, tend to decline in low quality forest patches, we plead for taking species ecology fully into account when predicting tropical community responses to habitat change.

Kenyan endemic bird species at home in novel ecosystem

Riparian thickets of East Africa harbor a large number of endemic animal and plant species, but also provide important ecosystem services for the human being settling along streams. This creates a conflicting situation between nature conservation and land-use activities. Today, most of this former pristine vegetation is highly degraded and became replaced by the invasive exotic Lantana camara shrub species. In this study, we analyze the movement behavior and habitat use of a diverse range of riparian bird species and model the habitat availability of each of these species. We selected the following four riparian bird species: Bare-eyed Thrush Turdus tephronotus, Rufous Chatterer Turdoides rubiginosus, Zanzibar Sombre Greenbul Andropadus importunus insularis, and the Kenyan endemic Hinde's Babbler Turdoides hindei. We collected telemetric data of 14 individuals during a 2 months radio-tracking campaign along the Nzeeu River in southeast Kenya. We found that (1) all four species had similar home-range sizes, all geographically restricted and nearby the river; (2) all species mainly use dense thicket, in particular the invasive L. camara; (3) human settlements were avoided by the bird individuals observed; (4) the birds' movement, indicating foraging behavior, was comparatively slow within thickets, but significantly faster over open, agricultural areas; and (5) habitat suitability models underline the relevance of L. camara as suitable surrogate habitat for all understoreyed bird species, but also show that the clearance of thickets has led to a vanishing of large and interconnected thickets and thus might have negative effects on the population viability in the long run.

Restricted movements and high site fidelity in three East African cloud-forest birds

Species with specific habitat requirements often remain within their habitat and are characterized by a very sedentary behaviour. We used radio-tracking during a 3-wk campaign to investigate the home ranges and movements of three East African passerine bird species, all adapted to cloud-forest habitats: montane white-eye Zosterops poliogaster mbuluensis, stripe-cheeked greenbul Andropadus milanjensis and white-starred robin Pogonocichla stellata macarthuri. Individuals were observed in a forest-grassland mosaic on top of Chyulu Hills, south Kenya. Based on 15 individuals with a total of 1041 fixes, we found (1) that all three species show a sedentary behaviour restricted to their home forest patch; (2) least activity during the afternoon; and (3) re-colonization into its home patch after translocation into a nearby forest patch. Our findings underline that forest-specialist bird species of the tropics show high site fidelity despite their potential movement ability.

Phenotypic evolution of an Atlantic Forest passerine (Xiphorhynchus fuscus): biogeographic and systematic implications

We studied the phenotypic variation of the Atlantic Forest passerine Xiphorhynchus fuscus (Aves: Dendrocolaptidae) with the broad aim of addressing whether the history and type of forest affected the evolution of endemic taxa. We also tested whether the different subspecies and genetic lineages of X. fuscus could be considered full species. We collected plumage and body size measurements and, in combination with genetic data, used multivariate tests to evaluate the working hypotheses. Our results, combined with previous biogeographic analyses, indicate that vicariant events have been important determinants in the evolution of phenotypic characters of X. fuscus, once genetic isolation was complete. Our analysis also suggests that forest heterogeneity and ecotones are important factors in the early evolution of Atlantic Forest taxa, perhaps via divergent selection. Forest instability during the Pleistocene was critical in the evolution of phenotypic traits. We confirm that the subspecies atlanticus should be considered a full species. Other lineages or populations are also phenotypically differentiated but we do not suggest considering them as full species. They share high levels of gene flow and are part of a continuous latitudinal cline of phenotypic variation. Our study suggests that not all the historic events in the Atlantic Forest that affected the evolution of genetic lineages also influenced the evolution of phenotypic characters in the same direction and intensity. Undoubtedly, natural selection played a major role in the evolution of Atlantic Forest organisms.

Sensitivity to fragmentation and spatial distribution of birds in forest fragments of northern paraná

In this study we investigated the relationship between the sensitivity to forest fragmentation of bird species and their habitat spatial distribution. We hypothesized that a homogenous spatial distribution is associated to habitat-generalist species, which would tend to be less sensitive to forest fragmentation; in contrast, a heterogeneous spatial distribution would drive to an increase of sensitivity to forest fragmentation. We concentrated on analyses of the suboscine birds, which are known to be closely associated to microhabitats. Field data was obtained in the Parque Estadual Mata dos Godoy (23°27′ S, 51°15′ W), southern Brazilian Atlantic forest. This reserve has high Biotic Integrity levels, with a relatively high number of recorded suboscines. Forty three species of suboscines were recorded, of which 21 species were considered to have high sensitivity and 22 to have low sensitivity to forest fragmentation. There was no association between levels of sensitivity to forest fragmentation and spatial distribution of suboscines. We only found significant correlation with the group of the subcanopy suboscines at the northern portion of Parque Estadual Mata dos Godoy. Therefore, we found a weak relationship between spatial distribution (habitat specialization) and sensitivity to forest fragmentation. The fact that habitat-specialist birds tend to live at the northern portion of Godoy State Park, which has the first type of terrain in a landscape to be converted into agriculture, indicate that that region has special importance for conservation.

Do shade-grown coffee plantations pose a disease risk for wild birds?

Shade-grown coffee plantations are often promoted as a conservation strategy for wild birds. However, these agro-ecosystems are actively managed for food production, which may alter bird behaviors or interactions that could change bird health, compared to natural forest. To examine whether there is a difference between the health parameters of wild birds inhabiting shade-grown coffee plantations and natural forest, we evaluated birds in Costa Rica for (1) their general body condition, (2) antibodies to pathogens, (paramyxovirus and Mycoplasma spp.), and (3) the prevalence and diversity of endo-, ecto-, and hemoparasites. We measured exposure to Mycoplasma spp. and paramyxovirus because these are pathogens that could have been introduced with domestic poultry, one mechanism by which these landscapes could be detrimental to wild birds. We captured 1,561 birds representing 75 species. Although seasonal factors influenced body condition, we did not find bird general body condition to be different. A total of 556 birds of 31 species were tested for antibodies against paramyxovirus-1. Of these, five birds tested positive, four of which were from shade coffee. Out of 461 other tests for pathogens (for antibodies and nucleotide detection), none were positive. Pterolichus obtusus, the feather mite of chickens, was found on 15 birds representing two species and all were from shade-coffee plantations. Larvated eggs of Syngamus trachea, a nematode typically associated with chickens, were found in four birds captured in shade coffee and one captured in forest. For hemoparasites, a total of 1,121 blood smears from 68 bird species were examined, and only one species showed a higher prevalence of infection in shade coffee. Our results indicate that shade-coffee plantations do not pose a significant health risk to forest birds, but at least two groups of pathogens may deserve further attention: Haemoproteus spp. and the diversity and identity of endoparasites.

Quantitative analysis of forest fragmentation in the atlantic forest reveals more threatened bird species than the current red list

Habitat loss and attendant fragmentation threaten the existence of many species. Conserving these species requires a straightforward and objective method that quantifies how these factors affect their survival. Therefore, we compared a variety of metrics that assess habitat fragmentation in bird ranges, using the geographical ranges of 127 forest endemic passerine birds inhabiting the Atlantic Forest of Brazil. A common, non-biological metric - cumulative area of size-ranked fragments within a species range - was misleading, as the least threatened species had the most habitat fragmentation. Instead, we recommend a modified version of metapopulation capacity. The metric links detailed spatial information on fragment sizes and spatial configuration to the birds' abilities to occupy and disperse across large areas (100,000+ km(2)). In the Atlantic Forest, metapopulation capacities were largely bimodal, in that most species' ranges had either low capacity (high risk of extinction) or high capacity (very small risk of extinction). This pattern persisted within taxonomically and ecologically homogenous groups, indicating that it is driven by fragmentation patterns and not differences in species ecology. Worryingly, we found IUCN considers some 28 of 58 species in the low metapopulation capacity cluster to not be threatened. We propose that assessing the effect of fragmentation will separate species more clearly into distinct risk categories than does a simple assessment of remaining habitat.

Female mate fidelity in a Lek mating system and its implications for the evolution of cooperative lekking behavior

The extent and importance of female mate fidelity in polygynous mating systems are poorly known. Fidelity may contribute to high variance in male reproductive success when it favors attractive mates or may stabilize social interactions if females are faithful to mating sites rather than males. Using 12 years of data on genetic mate choice in the cooperatively lekking lance-tailed manakin (Chiroxiphia lanceolata), I investigated the frequency of fidelity within and between years, whether females were faithful to individual males or to mating sites across years, and whether fidelity favored attractive males. Mate fidelity occurred in 41.7% of 120 between-year comparisons and was observed for 41.1% of 73 individual females that had the opportunity to mate faithfully. Females were not more likely to mate at prior mating sites when previous mates were replaced. Faithful females mated with the same male in up to four consecutive years but were not disproportionately faithful to attractive partners. Mating history influences current mate choice, and fidelity in this lekking system apparently represents active mate choice by females but little is not cited in the text. Please provide a citation or mark this reference for deletion.consensus in mate choices among faithful females. This study underscores the prevalence of mate fidelity in polygynous mating systems and emphasizes the need to consider the larger context of lifetime reproductive behavior when interpreting patterns of female choice.

Short-term forest management effects on a long-lived ectotherm

Timber harvesting has been shown to have both positive and negative effects on forest dwelling species. We examined the immediate effects of timber harvests (clearcuts and group selection openings) on ectotherm behavior, using the eastern box turtle as a model. We monitored the movement and thermal ecology of 50 adult box turtles using radiotelemetry from May-October for two years prior to, and two years following scheduled timber harvests in the Central Hardwoods Region of the U.S. Annual home ranges (7.45 ha, 100% MCP) did not differ in any year or in response to timber harvests, but were 33% larger than previous estimates (range 0.47-187.67 ha). Distance of daily movements decreased post-harvest (from 22 m±1.2 m to 15 m±0.9 m) whereas thermal optima increased (from 23±1°C to 25±1°C). Microclimatic conditions varied by habitat type, but monthly average temperatures were warmer in harvested areas by as much as 13°C. Animals that used harvest openings were exposed to extreme monthly average temperatures (∼40°C). As a result, the animals made shorter and more frequent movements in and out of the harvest areas while maintaining 9% higher body temperatures. This experimental design coupled with radiotelemetry and behavioral observation of a wild ectotherm population prior to and in response to anthropogenic habitat alteration is the first of its kind. Our results indicate that even in a relatively contiguous forested landscape with small-scale timber harvests, there are local effects on the thermal ecology of ectotherms. Ultimately, the results of this research can benefit the conservation and management of temperature-dependent species by informing effects of timber management across landscapes amid changing climates.

Breaking functional connectivity into components: a novel approach using an individual-based model, and first outcomes

Landscape connectivity is a key factor determining the viability of populations in fragmented landscapes. Predicting 'functional connectivity', namely whether a patch or a landscape functions as connected from the perspective of a focal species, poses various challenges. First, empirical data on the movement behaviour of species is often scarce. Second, animal-landscape interactions are bound to yield complex patterns. Lastly, functional connectivity involves various components that are rarely assessed separately. We introduce the spatially explicit, individual-based model FunCon as means to distinguish between components of functional connectivity and to assess how each of them affects the sensitivity of species and communities to landscape structures. We then present the results of exploratory simulations over six landscapes of different fragmentation levels and across a range of hypothetical bird species that differ in their response to habitat edges. i) Our results demonstrate that estimations of functional connectivity depend not only on the response of species to edges (avoidance versus penetration into the matrix), the movement mode investigated (home range movements versus dispersal), and the way in which the matrix is being crossed (random walk versus gap crossing), but also on the choice of connectivity measure (in this case, the model output examined). ii) We further show a strong effect of the mortality scenario applied, indicating that movement decisions that do not fully match the mortality risks are likely to reduce connectivity and enhance sensitivity to fragmentation. iii) Despite these complexities, some consistent patterns emerged. For instance, the ranking order of landscapes in terms of functional connectivity was mostly consistent across the entire range of hypothetical species, indicating that simple landscape indices can potentially serve as valuable surrogates for functional connectivity. Yet such simplifications must be carefully evaluated in terms of the components of functional connectivity they actually predict.