scholarly journals Comparative Phylogeography of Southern African Bird Species Suggests an Ephemeral Speciation Model

Diversity ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 434
Author(s):  
Gary Voelker ◽  
Guinevere O. U. Wogan ◽  
Jerry W. Huntley ◽  
Rauri C. K. Bowie
Keyword(s):  
Southern Africa ◽  
Ecological Niche Modeling ◽  
Abiotic Factors ◽  
Haplotype Diversity ◽  
Bird Species ◽  
Climatic Oscillations ◽  
Speciation Model ◽  
Distinct Haplotype ◽  
The Many ◽  
Central South

Southern Africa is remarkably rich in avian species diversity; however, the evolutionary and biogeographic mechanisms responsible for that diversity are, in general, poorly understood, and this is particularly true with respect to the many species that are endemic or near-endemic to the region. Here, we used mtDNA to assess genetic structure in three southern African bird species to determine whether each was genetically panmictic, or whether there was standing genetic variation upon which abiotic factors (e.g., climate, biome boundaries, geographic features) could have acted to drive lineage diversification. Haplotype diversity was partitioned into two (two species) or three (one species) distinct haplotype clusters that did not reflect biogeographic or biome partitioning; instead, haplotype clusters overlapped in central South Africa. Population and demographic analyses, along with ecological niche modeling and Bayesian Skyline Plots, indicated that each of the three species were likely isolated in refugia during Pleistocene climatic perturbations, with subsequent expansions from refugia resulting in present-day overlapping distributions. Collectively, our analyses suggest that an ephemeral speciation model is operating in southern Africa, driven by the dynamic climatic oscillations that characterize the region. At least some of the regional endemic bird species (e.g., White-eyes, Zosterops spp.) may be the result of sufficiently long periods in refugia as opposed to the distinct but ephemeral clusters recovered within our three focal species.

Biotics: Competition, Herbivory, Predation, Parasitism and Symbiosis

2017 ◽  
Author(s):  
Christer Brönmark ◽  
Lars-Anders Hansson
Keyword(s):  
Population Dynamics ◽  
Ecosystem Function ◽  
Theoretical Basis ◽  
Abiotic Factors ◽  
Biological Interactions ◽  
Natural Systems ◽  
The Many

If biological interactions, such as competition and predation, have any effect on population dynamics, or if abiotic factors alone determine which organisms, how many of them do we see in a specific ecosystem, was for long a controversial question. This chapter aims at providing the basis for the understanding of biological interactions, as well as showing ample examples of how important those interactions are in shaping both population dynamics and ecosystem function of natural systems. In addition to the many examples, the reader is introduced to the history and the theoretical basis for biological interactions.

scholarly journals Power line routing and configuration as major drivers of collision risk in two bustard species

Oryx ◽  
2020 ◽  
pp. 1-10 ◽  
Author(s):  
Ana Teresa Marques ◽  
Ricardo C. Martins ◽  
João Paulo Silva ◽  
Jorge M. Palmeirim ◽  
Francisco Moreira
Keyword(s):  
Abiotic Factors ◽  
Bird Species ◽  
Power Line ◽  
Power Lines ◽  
Mitigation Measures ◽  
Suitable Habitat ◽  
Collision Risk ◽  
Great Bustard ◽  
Line Configuration ◽  
Tetrax Tetrax

Abstract Collision with power lines is a major cause of mortality for many bird species. Understanding the biotic and abiotic factors that increase collision risk is therefore important for implementing mitigation measures to minimize mortality, such as power line rerouting or wire marking. Here, we used collision events registered during 2003–2015 along 280 km of transmission power lines in southern Portugal to analyse spatio-temporal patterns and collision risk factors in two sympatric, threatened, and collision-prone species: the great bustard Otis tarda and the little bustard Tetrax tetrax. The occurrence of collisions was not uniform across space and time, and variations could be explained by the species' ecological requirements, distribution patterns and behaviour. Although both species fly considerable distances between areas of suitable habitat, collisions were far more likely in power line sections with > 20% (for the little bustard) or > 50% (for the great bustard) of open farmland habitat in the surroundings. Power line configuration was also important: taller pylons and those with a higher number of wire levels posed a higher risk for both species. Wire marking had a small but significant effect for the little bustard, reducing collisions risk. There was, however, no similar effect for the great bustard, possibly a result of limited data. Mitigation measures should be implemented to prevent bustard collisions, including adequate route planning, ideally avoiding areas with > 20% of open habitat. Line configuration and wire marking are particularly important where such localities cannot be avoided and power lines cross areas with a high proportion of bustard habitat, including outside protected areas.

Feathers and flight

2020 ◽  
pp. 21-47
Author(s):  
Graham Scott
Keyword(s):  
Collision Avoidance ◽  
Wind Farm ◽  
Bird Species ◽  
Collision Risk ◽  
Basic Physics ◽  
Range Of Functions ◽  
Anatomical Adaptations ◽  
The Many

This chapter covers two themes: feathers and flight. It takes a close look at the many aspects of feathers—their evolution, structure, growth, maintenance, and their replacement through moult. The broad range of functions of feathers in display (including how different pigmentations arise), for insulation, and in flight are considered. Moult strategies are compared and discussed. The second part of the chapter describes the anatomical adaptations of birds to flight, and the process of flight itself. The basic physics, physiology and metabolism, and energetics of flight are covered in some detail. A review of studies on the neurological control of collision avoidance by flying birds and the implications in relation to wind-farm collision risk is given. The chapter ends with a discussion on the evolution of flight and subsequent flightlessness of some bird species.

Afterword Uncertain trajectories and refigured social worlds: the image entourage and other practices of digital and social media photography

Africa ◽  
2019 ◽  
Vol 89 (2) ◽  
pp. 323-328
Author(s):  
Corinne A. Kratz
Keyword(s):  
Social Media ◽  
Southern Africa ◽  
Social Practice ◽  
Social Worlds ◽  
Special Issue ◽  
Important Work ◽  
Photographic Images ◽  
The World ◽  
The Many ◽  
East West

Drawn from East, West, Central and Southern Africa, the case studies in this special issue build on several decades of important work on photography in Africa. That work has examined colonial photography and postcards, studio work from colonial times to the present, activist photography, photojournalism, and artists who work with photographic images. It has addressed issues of representation, portraiture, aesthetics, self-fashioning, identities, power and status, modernities and materiality, the roles of photographs in governance and everyday politics, and the many histories and modes of social practice around making, showing, viewing, exchanging, manipulating, reproducing, circulating and archiving photographic images. Yet these articles push such issues and topics in exciting directions by addressing new photographic circumstances emerging throughout the world, initiated through new media's technological shifts and possibilities. In Africa, this has fuelled a range of transformations over the last fifteen years or so, transformations that are still unfolding. As the articles show, digital images, mobile phone cameras and social media (also accessed via phone) constitute the potent triad that has set off these transformations.

scholarly journals A novel cellular structure in the retina of insectivorous birds

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Luke P. Tyrrell ◽  
Leandro B. C. Teixeira ◽  
Richard R. Dubielzig ◽  
Diana Pita ◽  
Patrice Baumhardt ◽  
...  
Keyword(s):  
Cellular Structure ◽  
Bird Species ◽  
Insectivorous Birds ◽  
Visual Channel ◽  
Oil Droplets ◽  
Rod Photoreceptors ◽  
Dim Light ◽  
Retinal Structure ◽  
The Many ◽  
Ecological Differences

Abstract The keen visual systems of birds have been relatively well-studied. The foundations of avian vision rest on their cone and rod photoreceptors. Most birds use four cone photoreceptor types for color vision, a fifth cone for achromatic tasks, and a rod for dim-light vision. The cones, along with their oil droplets, and rods are conserved across birds – with the exception of a few shifts in spectral sensitivity – despite taxonomic, behavioral and ecological differences. Here, however, we describe a novel photoreceptor organelle in a group of New World flycatchers (Empidonax spp.) in which the traditional oil droplet is replaced with a complex of electron-dense megamitochondria surrounded by hundreds of small, orange oil droplets. The photoreceptors with this organelle were unevenly distributed across the retina, being present in the central region (including in the fovea), but absent from the retinal periphery and the area temporalis of these insectivorous birds. Of the many bird species with their photoreceptors characterized, only the two flycatchers described here (E. virescens and E. minimus) possess this unusual retinal structure. We discuss the potential functional significance of this unique sub-cellular structure, which might provide an additional visual channel for these small predatory songbirds.

scholarly journals Urbanization, environmental stabilization and temporal persistence of bird species: a view from Latin America

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e6056 ◽  
Author(s):  
Lucas Matías Leveau
Keyword(s):  
Temporal Variation ◽  
Case Studies ◽  
Urban Areas ◽  
Abiotic Factors ◽  
Bird Species ◽  
Urban Environments ◽  
Temporal Scales ◽  
Urbanization Gradients ◽  
Temporal Stabilization ◽  
Bird Composition

BackgroundA scarcely studied consequence of urbanization is the effect of temporal stabilization of the environment on bird communities. This alteration is thought to dampen environmental variations between day and night, seasons and years, promoting a temporal persistence of bird composition in urban areas. The aim of this study was to review current evidence of temporal stabilization of biotic and abiotic factors in urban environments and the potential effects of such stabilization on temporal variation of bird species presence at different temporal scales.MethodsI selected the literature by searching published articles and book chapters using Scopus and Google scholar. I only included articles that compared the temporal variation of bird composition or resources between different levels of urbanization.ResultsIn general, there is evidence of temporal stabilization of abiotic and biotic factors at the three time scales considered. At the diurnal scale, the main factor considered was artificial light in the context of light pollution. At the seasonal and interannual scales, several case studies found a smaller temporal variation of primary productivity in urban than in natural and rural areas. Bird species composition showed more stabilization in urban environments at the three temporal scales: (1) several case studies reported bird activity at night, associated with artificial light; (2) studies in urban parks and along urbanization gradients showed smaller seasonal variation of bird composition in the more urbanized areas; and (3) in general, case studies along urbanization gradients showed smaller interannual variation of bird composition in the more urbanized areas, although some studies showed no relationships or opposite trends than expected.DiscussionThe published evidence suggests that urban areas dampen the natural cycles at several temporal scales. The stabilization of biotic and abiotic factors, such as light, temperature, food and habitat structure, is desynchronized from natural diurnal, seasonal and interannual cycles. However, there is a dearth of long-term comparisons of bird composition and studies that simultaneously analyze the relationship between resources and bird composition stabilization at the seasonal and interannual scales. More research is needed in the Southern hemisphere, where there is a lack of studies dealing with the seasonal and interannual variations of primary productivity along urbanization gradients and nocturnal activity of bird species. A future research agenda should include differentiation of spatial and temporal homogenization of avifaunas.

scholarly journals The Status and Threats of Birds: A Case Study of Birds in Nayapul to Ghandruk Area, Kaski, Nepal

2021 ◽  
pp. 18-32
Author(s):  
Subhas Chandra Bastola
Keyword(s):  
Crop Production ◽  
Abiotic Factors ◽  
Bird Species ◽  
Habitat Destruction ◽  
Bird Population ◽  
Factors Affecting ◽  
Storage Devices ◽  
The Status ◽  
Total Species

The purpose of this study is to quantify species diversity of birds in the study area and to explore the biotic and abiotic factors affecting the bird population. This study was carried out by using the fixed point counting method. The study area was situated in Annapurna Rural Municipality of Kaski district. A total of 147 bird species belonging to 46 families and 14 orders were identified in the study area. It was found that Muscicapidae was the largest family and Passeriformes the largest order. Among the reported species, 50% were residents, 31% were full-migrants, 18% were altitudinal migrants and the remaining were 1% nomadic. Habitats of birds included the forest 68%, the scrubland 17 %, the grassland 7% and the wetland 6 % of the study area. Similarly, the rocky area and artificial area covered 1% of the total species. The results showed that most of the bird species i.e. 136 were least concerned, 4 of them were nearly threatened, 3 of them were endangered, 3 were critically endangered and only one species was vulnerable. The most important threats included hunting and trapping, killing for fun, shift in crop production, use of insecticides and pesticides, improved storage devices, habitat destruction, developmental activities, tourism, buried carcasses and predatory.

scholarly journals Effects of clear-cutting and selective felling in Swedish Boreal coniferous forest: response of invertebrate taxa eaten by birds

1995 ◽  
Vol 6 (2-3) ◽  
pp. 79-90 ◽  
Author(s):  
Ola Atlegrim ◽  
Kjell Sjöberg
Keyword(s):  
Indirect Effects ◽  
Abiotic Factors ◽  
Coniferous Forest ◽  
Bird Species ◽  
Sun Exposure ◽  
Total Biomass ◽  
Insectivorous Birds ◽  
Short Term ◽  
Field Layer ◽  
Clear Cutting

Our aim was to analyse the short-term effects (0-4 years) of selective felling and clear-cutting on the food resources of insectivorous birds. Literature data on bird diets showed that herbivorous larvae (Lepidoptera and Hymenoptera: Symphyta) and spiders (Araneae) were used by 81 and 50%, respectively, of 16 bird species breeding in the Swedish boreal coniferous forest. A field study comparing selective fellings, clear-cuttings and uncut controls showed considerable effects of clear-cutting on both terricolous and field layer invertebrates. Clear-cuttings had significantly lower abundance and biomass, and a different composition of herbivorous larvae and spiders, as well as a lower total biomass of invertebrates in the field layer than controls. Drastic changes of abiotic factors (like increased temperature range) following clear-cutting may directly affect the occurrence of invertebrates. However, indirect effects (like increased sun exposure, affecting food plant quality for herbivorous larvae) are probably also responsible. Selective fellings did not differ from controls in the occurrence of herbivorous larvae and spiders. Therefore, over the four-year term of our study, selective felling seems to provide birds with conditions similar to uncut forest for invertebrates used by birds.

scholarly journals Modeling Spatial Distribution of Sergentomyia minuta (Diptera: Psychodidae) and its Potential Implication in Leishmaniasis Transmission in Morocco

2020 ◽  
Author(s):  
Morocco Mohamed Daoudi ◽  
Samia Boussaa ◽  
Ali Boumezzough
Keyword(s):  
Geographical Distribution ◽  
Ecological Niche Modeling ◽  
Abiotic Factors ◽  
Leishmania Species ◽  
Statistical Correlation ◽  
Sand Flies ◽  
Potential Implication ◽  
Factors Affecting ◽  
Precipitation Seasonality ◽  
Sergentomyia Minuta

Background: Leishmaniases are parasitic diseases caused by Leishmania species and transmitted by the bite of sand flies. The genus Lutzomyia and Phlebotomus of sand flies are known to be the responsible vector for transmitting almost all Leishmania species to humans. The detection of Leishmania DNA in species of the genus Sergentomyia, in different regions, suggests their likely role in Leishmania transmission. Methods: Our objective was to determine the potential geographical distribution of Sergentomyia minuta, the most dominant Sergentomyia species in Morocco, using ecological niche modeling. Results: The results showed the widespread geographical distribution of S. minuta in Morocco, specifically in northern and central Morocco where visceral and cutaneous leishmaniasis foci occur. There were six abiotic factors affecting the distribution of S. minuta whose annual precipitation, precipitation seasonality and precipitation of driest month as the most important ecological variables of the model. Conclusion: A positive statistical correlation between human leishmaniasis cases and S. minuta abundance was noted suggesting the potential involvement of S. minuta in local Leishmania transmission cycles.

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