75 research outputs found

    Fire and climate: contrasting pressures on tropical Andean timberline species

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    Department of Biological Sciences; Florida Institute of Technology; Melbourne FL USA Department of Biological Sciences; Florida Institute of Technology; Melbourne FL USA Department of Biological Sciences; Florida Institute of Technology; Melbourne FL USA Geography, College of Life & Environmental Sciences; University of Exeter; Exeter UK Department of Biological Sciences; Florida Institute of Technology; Melbourne FL USA CEPSAR; The Open University; Milton Keynes UK Instituto de Geología; Universidad Nacional Autónoma de México; Ciudad Universitaria; Mexico City Mexico Department of Forest and Soil Sciences; University of Natural Resources and Life Sciences Vienna; Vienna Austria Department of Biology and Center for Energy; Environment and Sustainability; Wake Forest University; Winston Salem NC USACopyright © 2015 John Wiley & Sons Ltd.Aim: The aim was to test competing hypotheses regarding migration of the Andean timberline within the last 2000 years. Location: The upper forest limit in Manu National Park, Peru. Methods: A randomized stratified design provided 21 soil profiles from forested sites just below the timberline, 15 from puna grassland sites just above the timberline and 15 from the transitional habitat at the puna–forest boundary. From each profile a surface sample (hereafter modern) and a sample from the base of the organic horizon (hereafter historical) were collected. Pollen and charcoal were analysed from the modern and historical layers of the 51 soil profiles. A chronological framework was provided by 24 14C dates. Data were ordinated as modern and historical groups and the temporal trends illustrated by Procrustes rotation. Results: The organic layer from the soil profiles represented the last 600–2000 years. Fire was much more abundant in all habitat types (puna, transitional and forested) in the modern compared with the historical groups. Samples that had historically been in puna just above the timberline showed encroachment by woody species. Samples that had been forested were still classified as forest but their composition had become more transitional. Sites that were transitional appeared to represent a new or expanded class of sites that was far less abundant historically. Main conclusions: Our results are consistent with ongoing warming causing an upslope migration of species, although not necessarily of the timberline. Weedy fire-tolerant species are spreading upslope, creating a transitional forest, softening the boundary between forest and puna. Simultaneously, fire introduced to improve grazing outside the park has increasingly penetrated the forest and is causing the upper timberline to shift towards more fire-tolerant and weedy species. Consequently, both the form of the ecotone between forest and grassland and the species composition of these forests is changing and is expected to continue to change, representing a shifting baseline for what is considered to be natural.Gordon and Betty Moore Foundation Andes-to-Amazon programmeBlue Moon FundNational Science Foundatio

    A strong conditional mutualism limits and enhances seed dispersal and germination of a tropical palm

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    Seed predation and seed dispersal can have strong effects on early life history stages of plants. These processes have often been studied as individual effects, but the degree to which their relative importance co-varies with seed predator abundance and how this influences seed germination rates is poorly understood. Therefore, we used a combination of observations and field experiments to determine the degree to which germination rates of the palm Astrocaryum mexicanum varied with abundance of a small mammal seed predator/disperser, Heteromysdesmarestianus, in a lowland tropical forest. Patterns of abundance of the two species were strongly related; density of H. desmarestianus was low in sites with low density of A. mexicanum and vice versa. Rates of predation and dispersal of A. mexicanum seeds depended on abundance of H. desmarestianus; sites with high densities of H. desmarestianus had the highest rates of seed predation and lowest rates of seed germination, but a greater total number of seeds were dispersed and there was greater density of seedlings, saplings, and adults of A. mexicanum in these sites. When abundance of H. desmarestianus was experimentally reduced, rates of seed predation decreased, but so did dispersal of A. mexicanum seeds. Critically, rates of germination of dispersed seeds were 5 times greater than undispersed seeds. The results suggest that the relationship between A. mexicanum and H. desmarestianus is a conditional mutualism that results in a strong local effect on the abundance of each species. However, the magnitude and direction of these effects are determined by the relative strength of opposing, but related, mechanisms. A. mexicanum nuts provide H. desmarestianus with a critical food resource, and while seed predation on A. mexicanum nuts by H. desmarestianus is very intense, A. mexicanum ultimately benefits because of the relatively high germination rates of its seeds that are dispersed by H. desmarestianus

    High morbid-mortability and reduced level of osteoporosis diagnosis among elderly people who had hip fractures in São Paulo City

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    OBJECTIVE: To know the morbid-mortality following an osteoporotic hip fracture in elderly patients living in São Paulo. PATIENTS AND METHODS: This study evaluated prospectively all patient over 60 years admitted in 2 school-hospitals in the city of São Paulo in a following 6-month period due to a osteoporotic proximal femur fracture. All of them filled up the Health Assessment Questionnaire (HAQ) and had their chart reviewed. After 6 months they were re-interviewed. Linear regression analysis was utilized to determine the factors related to functional ability. RESULTS: 56 patients were included (mean age 80.7 ± 7.9 years old, 80.4% females). After the 6-month follow up the mortality rate was 23.2%. Only 30% of the patients returned to their previous activities, and 11.6% became totally dependent. Factors related to worse functional ability after fracture were HAQ before fracture, institutionalization after fracture and age (r² 0.482). The diagnosis of osteoporosis was informed only by 13.9% of them, and just 11.6% received any treatment for that. CONCLUSION: Our results showed the great impact of these fractures on mortality and in the functional ability of these patients. Nevertheless, many of our physicians do not inform the patients about the diagnosis of osteoporosis and, consequently, the treatment of this condition is jeopardized.As fraturas osteoporóticas de fêmur proximal trazem graves conseqüências quanto à morbimortalidade e à qualidade de vida, mas desconhece-se este impacto no Brasil. OBJETIVO: Conhecer a morbimortalidade decorrente deste tipo de fraturas em idosos na cidade de São Paulo. MÉTODOS: Foram incluídos todos os pacientes com mais de 60 anos internados por fraturas de fêmur proximal durante seis meses, em dois hospitais de São Paulo. Os pacientes preencheram o questionário de capacidade funcional (HAQ), tiveram seu prontuário examinado e foram reavaliados após seis meses. Utilizou-se a análise de regressão linear para determinar os fatores relacionados à capacidade funcional. RESULTADOS: Cinqüenta e seis pacientes foram incluídos no estudo (80,7 ± 7,9 anos; 80,4% mulheres). A mortalidade em seis meses foi de 23,2%. Apenas 30% retornaram plenamente às suas atividades prévias e 11,6% tornaram-se completamente dependentes. Os fatores que mais bem conseguiram prever pior capacidade funcional após a fratura foram HAQ pré-fratura, institucionalização pós-fratura e idade (r² 0,482). Somente 13,9% receberam o diagnóstico de osteoporose e 11,6% iniciaram algum tratamento. CONCLUSÕES: Os resultados do presente estudo demonstram o impacto deste tipo de fraturas sobre a mortalidade e a capacidade funcional. Entretanto, a falha médica no diagnóstico e na orientação de tratamento da osteoporose permanece elevada.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaSanta Casa de Misericórdia de São Paulo Departamento de OrtopediaUNIFESP-EPM EPMUNIFESP, EPM, EPMSciEL

    Assessment of motor functioning in the preschool period

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    The assessment of motor functioning in young children has become increasingly important in recent years with the acknowledgement that motor impairment is linked with cognitive, language, social and emotional difficulties. However, there is no one gold standard assessment tool to investigate motor ability in children. The aim of the current paper was to discuss the issues related to the assessment of motor ability in young pre-school children and to provide guidelines on the best approach for motor assessment. The paper discusses the maturational changes in brain development at the preschool level in relation to motor ability. Other issues include sex differences in motor ability at this young age, and evidence for this in relation to sociological versus biological influences. From the previous literature it is unclear what needs to be assessed in relation to motor functioning. Should the focus be underlying motor processes or movement skill assessment? Several key assessment tools are discussed that produce a general measure of motor performance followed by a description of tools that assess specific skills, such as fine and gross motor, ball and graphomotor skills. The paper concludes with recommendations on the best approach in assessing motor function in pre-school children

    Plant trait and vegetation data along a 1314 m elevation gradient with fire history in Puna grasslands, Per\ufa

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    \ua9 2024. The Author(s). Alpine grassland vegetation supports globally important biodiversity and ecosystems that are increasingly threatened by climate warming and other environmental changes. Trait-based approaches can support understanding of vegetation responses to global change drivers and consequences for ecosystem functioning. In six sites along a 1314 m elevational gradient in Puna grasslands in the Peruvian Andes, we collected datasets on vascular plant composition, plant functional traits, biomass, ecosystem fluxes, and climate data over three years. The data were collected in the wet and dry season and from plots with different fire histories. We selected traits associated with plant resource use, growth, and life history strategies (leaf area, leaf dry/wet mass, leaf thickness, specific leaf area, leaf dry matter content, leaf C, N, P content, C and N isotopes). The trait dataset contains 3,665 plant records from 145 taxa, 54,036 trait measurements (increasing the trait data coverage of the regional flora by 420%) covering 14 traits and 121 plant taxa (ca. 40% of which have no previous publicly available trait data) across 33 families

    Metabolomic analysis of human disease and its application to the eye

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    Metabolomics, the analysis of the metabolite profile in body fluids or tissues, is being applied to the analysis of a number of different diseases as well as being used in following responses to therapy. While genomics involves the study of gene expression and proteomics the expression of proteins, metabolomics investigates the consequences of the activity of these genes and proteins. There is good reason to think that metabolomics will find particular utility in the investigation of inflammation, given the multi-layered responses to infection and damage that are seen. This may be particularly relevant to eye disease, which may have tissue specific and systemic components. Metabolomic analysis can inform us about ocular or other body fluids and can therefore provide new information on pathways and processes involved in these responses. In this review, we explore the metabolic consequences of disease, in particular ocular conditions, and why the data may be usefully and uniquely assessed using the multiplexed analysis inherent in the metabolomic approach

    Biased-corrected richness estimates for the Amazonian tree flora

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    Amazonian forests are extraordinarily diverse, but the estimated species richness is very much debated. Here, we apply an ensemble of parametric estimators and a novel technique that includes conspecific spatial aggregation to an extended database of forest plots with up-to-date taxonomy. We show that the species abundance distribution of Amazonia is best approximated by a logseries with aggregated individuals, where aggregation increases with rarity. By averaging several methods to estimate total richness, we confirm that over 15,000 tree species are expected to occur in Amazonia. We also show that using ten times the number of plots would result in an increase to just ~50% of those 15,000 estimated species. To get a more complete sample of all tree species, rigorous field campaigns may be needed but the number of trees in Amazonia will remain an estimate for years to come

    Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

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    This is the final version. Available on open access from Wiley via the DOI in this recordData availability statement: The percentages of dispersal modes per plot are included as Supporting Information (Table S7, based on 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests in Amazonia). The dispersal modes assigned to these 5433 species and morphospecies are also included as Supporting Information (Table S8).Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types.Colombian institution Departamento Administrativo de Ciencia, Tecnología e Innovación COLCIENCIASFaculty of Sciences, Universidad de los Ande

    Consistent patterns of common species across tropical tree communities

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    Trees structure the Earth’s most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations1,2,3,4,5,6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth’s 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world’s most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees
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