Understanding how continental radiations are assembled across space and time is a major question in macroevolutionary biology. Here, we use a phylogenomic-scale phylogeny, a comprehensive morphological dataset, and environmental niche models to evaluate the relationship between trait and environment and assess the role of geography and niche conservatism in the continental radiation of Australian blindsnakes. The Australo-Papuan blindsnake genus, Anilios, comprises 47 described species of which 46 are endemic to and distributed across various biomes on continental Australia.
View Article and Find Full Text PDFCoevolution between interacting species is thought to increase biodiversity, but evidence linking microevolutionary processes to macroevolutionary patterns is scarce. We leveraged two decades of behavioral research coupled with historical DNA analysis to reveal that coevolution with hosts underpins speciation in brood-parasitic bronze-cuckoos. At a macroevolutionary scale, we show that highly virulent brood-parasitic taxa have higher speciation rates and are more likely to speciate in sympatry than less-virulent and nonparasitic relatives.
View Article and Find Full Text PDFBackground: Biodiversity exists at different levels of organisation: e.g. genetic, individual, population, species, and community.
View Article and Find Full Text PDFClimate's effect on global biodiversity is typically viewed through the lens of temperature, humidity and resulting ecosystem productivity. However, it is not known whether biodiversity depends solely on these climate conditions, or whether the size and fragmentation of these climates are also crucial. Here we shift the common perspective in global biodiversity studies, transitioning from geographic space to a climate-defined multidimensional space.
View Article and Find Full Text PDFMountains are among the most biodiverse regions on the planet, and how these landforms shape diversification through the interaction of biological traits and geo-climatic dynamics is integral to understanding global biodiversity. In this study, we investigate the dual roles of climate change and mountain uplift on the evolution of a hyper-diverse radiation, Liolaemus lizards, with a spatially explicit model of diversification using a reconstruction of uplift and paleotemperature in central and southern South America. The diversification model captures a hotspot for Liolaemus around 40°S in lineages with low-dispersal ability and narrow niche breadths.
View Article and Find Full Text PDFFaunal turnover in Indo-Australia across Wallace's Line is one of the most recognizable patterns in biogeography and has catalyzed debate about the role of evolutionary and geoclimatic history in biotic interchanges. Here, analysis of more than 20,000 vertebrate species with a model of geoclimate and biological diversification shows that broad precipitation tolerance and dispersal ability were key for exchange across the deep-time precipitation gradient spanning the region. Sundanian (Southeast Asian) lineages evolved in a climate similar to the humid "stepping stones" of Wallacea, facilitating colonization of the Sahulian (Australian) continental shelf.
View Article and Find Full Text PDFThree major axes of global change put the world's mammal biodiversity at risk: climate change, human population growth, and land-use change. In some parts of the world the full effects of these threats on species will only be felt in decades to come, yet conservation emphasizes species currently threatened with extinction, by threats that have already occurred. There have been calls for conservation to become more proactive by anticipating and protecting species that may not yet be threatened, but have a high chance of becoming threatened in the future.
View Article and Find Full Text PDFBiodiversity varies predictably with environmental energy around the globe, but the underlaying mechanisms remain incompletely understood. The evolutionary speed hypothesis predicts that environmental kinetic energy shapes variation in speciation rates through temperature- or life history-dependent rates of evolution. To test whether variation in evolutionary speed can explain the relationship between energy and biodiversity in birds, mammals, amphibians, and reptiles, we simulated diversification over 65 myr of geological and climatic change with a spatially explicit eco-evolutionary simulation model.
View Article and Find Full Text PDFHow biotic and abiotic factors act together to shape biological diversity is a major question in evolutionary biology. The recent availability of large datasets and development of new methodological approaches provide new tools to evaluate the predicted effects of ecological interactions and geography on lineage diversification and phenotypic evolution. Here, we use a near complete phylogenomic-scale phylogeny and a comprehensive morphological dataset comprising more than a thousand specimens to assess the role of biotic and abiotic processes in the diversification of monitor lizards (Varanidae).
View Article and Find Full Text PDFProc Natl Acad Sci U S A
October 2021
Far from a uniform band, the biodiversity found across Earth's tropical moist forests varies widely between the high diversity of the Neotropics and Indomalaya and the relatively lower diversity of the Afrotropics. Explanations for this variation across different regions, the "pantropical diversity disparity" (PDD), remain contentious, due to difficulty teasing apart the effects of contemporary climate and paleoenvironmental history. Here, we assess the ubiquity of the PDD in over 150,000 species of terrestrial plants and vertebrates and investigate the relationship between the present-day climate and patterns of species richness.
View Article and Find Full Text PDFProcesses driving the divergence of floral traits may be integral to the extraordinary richness of flowering plants and the assembly of diverse plant communities. Several models of pollinator-mediated floral evolution have been proposed; floral divergence may (i) be directly involved in driving speciation or may occur after speciation driven by (ii) drift or local adaptation in allopatry or (iii) negative interactions between species in sympatry. Here, we generate predictions for patterns of trait divergence and community assembly expected under these three models, and test these predictions in (Proteaceae), a diverse genus in the Southwest Australian biodiversity hotspot.
View Article and Find Full Text PDFSpicier food in hot countries has been explained in terms of natural selection on human cultures, with spices with antimicrobial effects considered to be an adaptation to increased risk of foodborne infection. However, correlations between culture and environment are difficult to interpret, because many cultural traits are inherited together from shared ancestors, neighbouring cultures are exposed to similar conditions, and many cultural and environmental variables show strong covariation. Here, using a global dataset of 33,750 recipes from 70 cuisines containing 93 different spices, we demonstrate that variation in spice use is not explained by temperature and that spice use cannot be accounted for by diversity of cultures, plants, crops or naturally occurring spices.
View Article and Find Full Text PDFComparative models used to predict species threat status can help identify the diagnostic features of species at risk. Such models often combine variables measured at the species level with spatial variables, causing multiple statistical challenges, including phylogenetic and spatial non-independence. We present a novel Bayesian approach for modelling threat status that simultaneously deals with both forms of non-independence and estimates their relative contribution, and we apply the approach to modelling threat status in the Australian plant genus We find that after phylogenetic and spatial effects are accounted for, species with greater evolutionary distinctiveness and a shorter annual flowering period are more likely to be threatened.
View Article and Find Full Text PDFBiome shifts are thought to be relatively rare, but some clades shift among starkly different environments with relative ease. What causes these shifts, and how do they shape phenotypic evolution? Roycroft et al. found that biome shifts in the Pseudomys Division of murid rodents were repeatedly accompanied by body size evolution in accordance with Bergmann's rule, suggesting adaptive evolution in response to changing climate conditions.
View Article and Find Full Text PDFMediterranean-type ecosystems (MTEs) contain exceptional plant diversity. Explanations for this diversity are usually classed as either "equilibrium," with elevated MTE diversity resulting from greater ecological carrying capacities, or "non-equilibrium," with MTEs having a greater accumulation of diversity over time than other types of ecosystems. These models have typically been considered as mutually exclusive.
View Article and Find Full Text PDFInferring the geographic mode of speciation could help reveal the evolutionary and ecological mechanisms that underlie the generation of biodiversity. Comparative methods have sought to reconstruct the geographic speciation history of clades, using data on phylogeny and species geographic ranges. However, inference from comparative methods has been limited by uncertainty over whether contemporary biodiversity data retain the historic signal of speciation.
View Article and Find Full Text PDFTask sharing, the involvement of non-specialists (non-physician clinicians or non-specialist physicians) in performing tasks originally reserved for surgeons and anesthesiologists, can be a potent strategy in bridging the vast human resource gap in surgery and anesthesia and bringing needed surgical care to the district level especially in low-resource countries. Although a common practice, the idea of assigning advanced tasks to less-specialized workers remains a subject of controversy. In order to optimize its benefits, it is helpful to understand the current task sharing landscape, its challenges, and its promise.
View Article and Find Full Text PDFThe causes of exceptionally high plant diversity in Mediterranean-climate biodiversity hotspots are not fully understood. We asked whether a mechanism similar to the tropical niche conservatism hypothesis could explain the diversity of four large genera (Protea, Moraea, Banksia, and Hakea) with distributions within and adjacent to the Greater Cape Floristic Region (South Africa) or the Southwest Floristic Region (Australia). Using phylogenetic and spatial data we estimated the environmental niche of each species, and reconstructed the mode and dynamics of niche evolution, and the geographic history, of each genus.
View Article and Find Full Text PDFBackground: This article reports on the use of the 'neighborhood method' to measure the prevalence and basic characteristics of children who became separated from their parents or usual caregivers subsequent to an attack by the M23 militia group in North Kivu, Democratic Republic of the Congo.
Methods: A two-stage household cluster survey was conducted in 522 households in North Kivu in August 2014. Heads of households were asked about separated children in their household, as well as the households of their two closest neighbors.
Comparative analyses of extinction risk routinely apply methods that account for phylogenetic non-independence, but few analyses of extinction risk have addressed the possibility of spatial non-independence. We explored patterns of extinction risk in Banksia, a plant genus largely endemic to Australia's southwest biodiversity hotspot, using methods to partition the variance in two response variables (threat status and range size) into phylogenetic, spatial, and independent components. We then estimated the effects of a number of biological and external predictors on extinction risk independently of phylogeny and space.
View Article and Find Full Text PDFJ Palliat Care
September 1996
The final three days of life of 50 consecutive patients on a busy integrated palliative care service is described, with regard to final cause of death, symptom control, drug prescription, retention of personal function, and other measures possibly relevant to dignity in dying. Good symptom relief was maintained without rapid or high escalation of doses of morphine or sedatives. Personal function was maintained in at least a moderate degree in the majority of patients.
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