Habitat shifts in the evolutionary history of a Neotropical flycatcher lineage from forest and open landscapes

<p>Abstract</p> <p>Background</p> <p>Little is known about the role ecological shifts play in the evolution of Neotropical radiations that have colonized a variety of environments. We here examine habitat shifts in the evolutionary history of <it>Elaenia </it>flycatchers, a Neotropical bird lineage that lives in a range of forest and open habitats. We evaluate phylogenetic relationships within the genus based on mitochondrial and nuclear DNA sequence data, and then employ parsimony-based and Bayesian methods to reconstruct preferences for a number of habitat types and migratory behaviour throughout the evolutionary history of the genus. Using a molecular clock approach, we date the most important habitat shifts.</p> <p>Results</p> <p>Our analyses resolve phylogenetic relationships among <it>Elaenia </it>species and confirm several species associations predicted by morphology while furnishing support for other taxon placements that are in conflict with traditional classification, such as the elevation of various <it>Elaenia </it>taxa to species level. While savannah specialism is restricted to one basal clade within the genus, montane forest was invaded from open habitat only on a limited number of occasions. Riparian growth may have been favoured early on in the evolution of the main <it>Elaenia </it>clade and subsequently been deserted on several occasions. Austral long-distance migratory behaviour evolved on several occasions.</p> <p>Conclusion</p> <p>Ancestral reconstructions of habitat preferences reveal pronounced differences not only in the timing of the emergence of certain habitat preferences, but also in the frequency of habitat shifts. The early origin of savannah specialism in <it>Elaenia </it>highlights the importance of this habitat in Neotropical Pliocene and late Miocene biogeography. While forest in old mountain ranges such as the Tepuis and the Brazilian Shield was colonized early on, the most important colonization event of montane forest was in conjunction with Pliocene Andean uplift. Riparian habitats may have played an important role in facilitating habitat shifts by birds expanding up the mountains along streams and adapting to newly emerging montane forest habitat.</p

Inter-familial relationships of the shorebirds (Aves: Charadriiformes) based on nuclear DNA sequence data

BACKGROUND: Phylogenetic hypotheses of higher-level relationships in the order Charadriiformes based on morphological data, partly disagree with those based on DNA-DNA hybridisation data. So far, these relationships have not been tested by analysis of DNA sequence data. Herein we utilize 1692 bp of aligned, nuclear DNA sequences obtained from 23 charadriiform species, representing 15 families. We also test earlier suggestions that bustards and sandgrouses may be nested with the charadriiforms. The data is analysed with methods based on the parsimony and maximum-likelihood criteria. RESULTS: Several novel phylogenetic relationships were recovered and strongly supported by the data, regardless of which method of analysis was employed. These include placing the gulls and allied groups as a sistergroup to the sandpiper-like birds, and not to the plover-like birds. The auks clearly belong to the clade with the gulls and allies, and are not basal to most other charadriiform birds as suggested in analyses of morphological data. Pluvialis, which has been supposed to belong to the plover family (Charadriidae), represents a basal branch that constitutes the sister taxon to a clade with plovers, oystercatchers and avocets. The thick-knees and sheathbills unexpectedly cluster together. CONCLUSION: The DNA sequence data contains a strong phylogenetic signal that results in a well-resolved phylogenetic tree with many strongly supported internodes. Taxonomically it is the most inclusive study of shorebird families that relies on nucleotide sequences. The presented phylogenetic hypothesis provides a solid framework for analyses of macroevolution of ecological, morphological and behavioural adaptations observed within the order Charadriiformes

The acceptability and feasibility of peer worker support role in community based HCV treatment for injecting drug users

Hepatitis C is the most common blood borne virus in Australia affecting over 200 000 people. Effective treatment for hepatitis C has only become accessible in Australia since the late 1990's, although active injecting drug use (IDU) remained an exclusion criteria for government-funded treatment until 2001. Treatment uptake has been slow, particularly among injecting drug users, the largest affected group. We developed a peer-based integrated model of hepatitis C care at a community drug and alcohol clinic. Clients interested and eligible for hepatitis C treatment had their substance use, mental health and other psychosocial comorbidities co-managed onsite at the clinic prior to and during treatment. In a qualitative preliminary evaluation of the project, nine current patients of the clinic were interviewed, as was the clinic peer worker. A high level of patient acceptability of the peer-based model and an endorsement the integrated model of care was found. This paper describes the acceptability of a peer-based integrated model of hepatitis C care by the clients using the service

Trophic niche shifts and phenotypic trait evolution are largely decoupled in Australasian parrots

Background: Trophic shifts from one dietary niche to another have played major roles in reshaping the evolutionary trajectories of a wide range of vertebrate groups, yet their consequences for morphological disparity and species diversity differ among groups. Methods: Here, we use phylogenetic comparative methods to examine whether the evolution of nectarivory and other trophic shifts have driven predictable evolutionary pathways in Australasian psittaculid parrots in terms of ecological traits such as body size, beak shape, and dispersal capacity. Results: We found no evidence for an ‘early-burst’ scenario of lineage or morphological diversification. The bestfitting models indicate that trait evolution in this group is characterized by abrupt phenotypic shifts (evolutionary jumps), with no sign of multiple phenotypic optima correlating with different trophic strategies. Thus, our results point to the existence of weak directional selection and suggest that lineages may be evolving randomly or slowly toward adaptive peaks they have not yet reached. Conclusions: This study adds to a growing body of evidence indicating that the relationship between avian morphology and feeding ecology may be more complex than usually assumed and highlights the importance of adding more flexible models to the macroevolutionary toolbox.info:eu-repo/semantics/publishedVersio

Mobile Air Quality Studies (MAQS) - an international project

Due to an increasing awareness of the potential hazardousness of air pollutants, new laws, rules and guidelines have recently been implemented globally. In this respect, numerous studies have addressed traffic-related exposure to particulate matter using stationary technology so far. By contrast, only few studies used the advanced technology of mobile exposure analysis. The Mobile Air Quality Study (MAQS) addresses the issue of air pollutant exposure by combining advanced high-granularity spatial-temporal analysis with vehicle-mounted, person-mounted and roadside sensors. The MAQS-platform will be used by international collaborators in order 1) to assess air pollutant exposure in relation to road structure, 2) to assess air pollutant exposure in relation to traffic density, 3) to assess air pollutant exposure in relation to weather conditions, 4) to compare exposure within vehicles between front and back seat (children) positions, and 5) to evaluate "traffic zone"- exposure in relation to non-"traffic zone"-exposure. Primarily, the MAQS-platform will focus on particulate matter. With the establishment of advanced mobile analysis tools, it is planed to extend the analysis to other pollutants including including NO2, SO2, nanoparticles, and ozone

Sacrifice in suburbia: American novels as troubled tragedies

In this thesis I enlist the mimetic theory of René Girard to argue that three twentieth-century American novels — Jeffrey Eugenides’ The Virgin Suicides, Rick Moody’s The Ice Storm, and Richard Yates’s Revolutionary Road — are tragic texts. I demonstrate that these novels are participating in a tradition begun in sacrificial ritual and myth, in which a victim is blamed for a crisis and sacrificed for the benefit of a troubled community. I then argue that the tragic sacrifice is subverted and complicated by various textual means, subcategorising the novels as ‘anti-tragedies’ that present the characteristic features of tragedy but problematise its cathartic effects. To ground my analysis, I establish an understanding of the American Dream as tragic, by examining three non-fiction texts on the Dream. I then briefly consider Arthur Miller’s Death of a Salesman as a play that deploys tragedy as discourse about the American Dream, before moving to a critical evaluation of the three novels. I make a case for the legitimacy of considering the novel as part of the tradition of tragedy. I find that each novel contains a plethora of tragic tropes—those thematic features of ritual and myth identified by Girard, the treatment of which is significant in terms of cathartic effect. I argue that the novel has a unique capacity to problematise its own narrative and thus function as a ‘self conscious’ tragedy, and that this self-consciousness makes sacrifice the subject of the text rather than a structural element within it. Girard’s mimetic theory has been criticised for its lack of attention to gender and to the experiences of women. My analysis of the significance of the female bodies in Eugenides’, Moody’s, and Yates’s novels extends Girardian scholarship in its consideration of women as scapegoats, and pays particular attention to gender in ways that Girard himself has not. I iv present evidence that the narrative attitude towards select female bodies in the three novels is directly relevant to their eligibility as Girardian scapegoats. Whereas previous Girardian scholarship has analysed novels for their treatment of one or more aspects of mimetic theory, such as mimetic desire or scapegoating, my thesis is the first work to analyse modern novels as tragedies: that is, as narratives in dialogue with the entire story-arc of ritual and myth. In doing so, my thesis strengthens the Girardian claim that tragedies are sacrificial scapegoat-rituals in narrative form. I then take Girard’s minor remarks about the ‘anti-mythical’ nature of modern tragedies, and extend this speculation into a detailed analysis of how such modern tragedies enact their anti-tragic subversions.Thesis (Ph.D.) -- University of Adelaide, School of Humanities, 201

Data from: Ecological opportunity and the evolution of habitat preferences in an arid-zone bird: implications for speciation in a climate-modified landscape

Bioclimatic models are widely used to investigate the impacts of climate change on species distributions. Range shifts are expected to occur as species track their current climate niche yet the potential for exploitation of new ecological opportunities that may arise as ecosystems and communities remodel is rarely considered. Here we show that grasswrens of the Amytornis textilis-modestus complex responded to new ecological opportunities in Australia’s arid biome through shifts in habitat preference following the development of chenopod shrublands during the late Plio-Pleistocene. We find evidence of spatially explicit responses to climatically driven landscape changes including changes in niche width and patterns of population growth. Conservation of structural and functional aspects of the ancestral niche appear to have facilitated recent habitat shifts, while demographic responses to late Pleistocene climate change provide evidence for the greater resilience of populations inhabiting the recently evolved chenopod shrubland communities. Similar responses could occur under future climate change in species exposed to novel ecological conditions, or those already occupying spatially heterogeneous landscapes. Mechanistic models that consider structural and functional aspects of the niche along with regional hydro-dynamics may be better predictors of future climate responses in Australia’s arid biome than bioclimatic models alone

DNA and the museum tradition

Volume: 123AStart Page: 52End Page: 6