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1.
Ecotoxicology ; 32(8): 1096-1123, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37907784

RESUMO

Environmental mercury (Hg) contamination of the global tropics outpaces our understanding of its consequences for biodiversity. Knowledge gaps of pollution exposure could obscure conservation threats in the Neotropics: a region that supports over half of the world's species, but faces ongoing land-use change and Hg emission via artisanal and small-scale gold mining (ASGM). Due to their global distribution and sensitivity to pollution, birds provide a valuable opportunity as bioindicators to assess how accelerating Hg emissions impact an ecosystem's ability to support biodiversity, and ultimately, global health. We present the largest database on Neotropical bird Hg concentrations (n = 2316) and establish exposure baselines for 322 bird species spanning nine countries across Central America, South America, and the West Indies. Patterns of avian Hg exposure in the Neotropics broadly align with those in temperate regions: consistent bioaccumulation across functional groups and high spatiotemporal variation. Bird species occupying higher trophic positions and aquatic habitats exhibited elevated Hg concentrations that have been previously associated with reductions in reproductive success. Notably, bird Hg concentrations were over four times higher at sites impacted by ASGM activities and differed by season for certain trophic niches. We developed this synthesis via a collaborative research network, the Tropical Research for Avian Conservation and Ecotoxicology (TRACE) Initiative, which exemplifies inclusive, equitable, and international data-sharing. While our findings signal an urgent need to assess sampling biases, mechanisms, and consequences of Hg exposure to tropical avian communities, the TRACE Initiative provides a meaningful framework to achieve such goals. Ultimately, our collective efforts support and inform local, scientific, and government entities, including Parties of the United Nations Minamata Convention on Mercury, as we continue working together to understand how Hg pollution impacts biodiversity conservation, ecosystem function, and public health in the tropics.


RESúMEN: La contaminación ambiental por mercurio (Hg) en los trópicos supera nuestra comprensión de sus consecuencias para la biodiversidad. Los vacíos de conocimiento que existen sobre la exposición a la contaminación podrían ocultar las amenazas para la conservación en el Neotrópico: una región que alberga a más de la mitad de las especies del mundo, pero que enfrenta una continua intensificación de las emisiones de Hg y del cambio de uso del suelo por el avance de la minería de oro artesanal y de pequeña escala (MAPE). Debido a su distribución global y su sensibilidad a la contaminación, las aves brindan una oportunidad valiosa como bioindicadores para evaluar cómo las emisiones de Hg afectan la capacidad de un ecosistema para sustentar la biodiversidad y, en última instancia, la salud global. Presentamos la más grande base de datos sobre concentraciones de Hg en aves Neotropicales (n = 2,316) para establecer una línea base para los niveles de exposición a Hg en 322 especies de aves de nueve países de América Central, América del Sur, y el Caribe. Encontramos patrones de las concentraciones de Hg en aves de los trópicos que se asemejan a los de las regiones templadas: mostrando una bioacumulación consistente a través de grupos funcionales y una alta variación espaciotemporal. Las especies de aves que ocupan posiciones más altas en la cadena trófica y en hábitats acuáticos registraron concentraciones elevadas de Hg que podrían tener efectos negativos en su éxito reproductivo. Es importante resaltar que las concentraciones de Hg en las aves de los sitios afectados por la MAPE fueron cuatro veces más altas que las de los sitios control y además difirió por temporada para ciertos nichos tróficos. Desarrollamos esta síntesis a través de una red de investigación colaborativa, la Iniciativa de Investigación Tropical para la Conservación y Ecotoxicología Aviar (TRACE), que ejemplifica un intercambio de datos inclusivo, equitativo e internacional. Si bien nuestros hallazgos sugieren una necesidad urgente de evaluar los sesgos en el muestreo, los mecanismos, y las consecuencias de la exposición al Hg en las comunidades de aves tropicales, la Iniciativa TRACE proporciona un marco para abordar estos objetivos. Nuestro esfuerzo colectivo tiene como propósito respaldar y brindar información a las entidades locales, científicas, y gubernamentales, incluyendo las Partes de la Convención de Minamata de las Naciones Unidas sobre el Mercurio, mientras continuamos trabajando juntos para comprender cómo la contaminación por Hg en los trópicos puede afectar la salud pública, el funcionamiento de los ecosistemas, y la conservación de la biodiversidad. Total mercury (THg) concentrations (µg/g) and sample sizes of birds across Central America, South America, and the West Indies from 2007­2023. Point size and color are arranged in order of increasing THg concentration and hexagonal grid cells are colored in terms of increasing sample size.


Assuntos
Mercúrio , Animais , Mercúrio/análise , Monitoramento Ambiental , Ecossistema , Poluição Ambiental , Ouro , Aves
2.
Ecology ; 104(12): e4175, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37781963

RESUMO

Effective solutions to conserve biodiversity require accurate community- and species-level information at relevant, actionable scales and across entire species' distributions. However, data and methodological constraints have limited our ability to provide such information in robust ways. Herein we employ a Deep-Reasoning Network implementation of the Deep Multivariate Probit Model (DMVP-DRNets), an end-to-end deep neural network framework, to exploit large observational and environmental data sets together and estimate landscape-scale species diversity and composition at continental extents. We present results from a novel year-round analysis of North American avifauna using data from over nine million eBird checklists and 72 environmental covariates. We highlight the utility of our information by identifying critical areas of high species diversity for a single group of conservation concern, the North American wood warblers, while capturing spatiotemporal variation in species' environmental associations and interspecific interactions. In so doing, we demonstrate the type of accurate, high-resolution information on biodiversity that deep learning approaches such as DMVP-DRNets can provide and that is needed to inform ecological research and conservation decision-making at multiple scales.


Assuntos
Ciência do Cidadão , Aprendizado Profundo , Biodiversidade
3.
Conserv Biol ; : e14194, 2023 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-37811734

RESUMO

We evaluated the impact of a philanthropic program investing in the conservation of sites along the Pacific Americas Flyway, which spans >16,000 km of coastline and is used by millions of shorebirds. Using a quasi-experimental, mixed methods approach, we estimated what would have happened to shorebird populations at 17 wintering sites without the sustained and additional investment they received. We modeled shorebird populations across the entire flyway and at sites with and without investment. Combining shorebird abundance estimates with a land-cover classification model, we used the synthetic control method to create counterfactuals for shorebird trends at the treatment sites. We found no evidence of an overall effect across three outcome variables. Species- and site-level treatment effects were heterogeneous, with a few cases showing evidence of a positive effect, including a site with a high level of overall investment. Results suggest six shorebirds declined across the entire flyway, including at many Latin American sites. However, the percentage of flyway populations present at the sites remained stable, and the percentage at the treatment sites was higher (i.e., investment sites) than at control sites. Multiple mechanisms behind our results are possible, including that investments have yet to mitigate impacts and negative impacts at other sites are driving declines at the treatment sites. A limitation of our evaluation is the sole focus on shorebird abundance and the lack of data that prohibits the inclusion of other outcome variables. Monitoring infrastructure is now in place to design a more robust and a priori shorebird evaluation framework across the entire flyway. With this framework, it will prove easier to prioritize limited dollars to result in the most positive conservation outcomes.


Evaluación del impacto de la inversión para la conservación enfocada en especies migratorias de largo recorrido Resumen Evaluamos el impacto de un programa filantrópico que invierte en la conservación de sitios a lo largo de la Ruta Migratoria Pacífico-Américas, la cual abarca >16,000 km de la línea costera y millones de aves playeras la usan. Estimamos con una estrategia cuasiexperimental y de métodos mixtos lo que habría pasado con las poblaciones de estas aves en 17 sitios invernales sin la inversión adicional y continua que recibieron. Modelamos estas poblaciones en toda la ruta y en sitios con y sin inversión. Combinamos las estimaciones de aves playeras con el modelo de clasificación de la cobertura del suelo y usamos el método de control sintético para crear contrafactuales para las tendencias de las aves playeras en sitios de tratamiento. No encontramos evidencia alguna de un efecto generalizado en las tres variables de los resultados. Los efectos del tratamiento de especies y de sitio fueron heterogéneos, con unos cuantos casos que mostraron evidencia de un efecto positivo, incluido un sitio con un nivel elevado de inversión general. Los resultados sugieren que seis especies de aves playeras declinaron a lo largo de toda la ruta, incluyendo en varios sitios de América Latina. Sin embargo, el porcentaje de poblaciones de la ruta presentes en los sitios permaneció estable y el porcentaje en los sitios de tratamiento (sitios de inversión) fue más elevado que en los sitios control. Muchos mecanismos son posibles detrás de nuestros resultados, incluidas las inversiones que todavía no han mitigado impactos y los impactos negativos en otros sitios que están causando las declinaciones en los sitios de tratamiento. Una limitación en nuestra evaluación es el enfoque único en la abundancia de aves playeras y la falta de datos que impiden la inclusión de otras variables de los resultados. El monitoreo de la infraestructura ahora está en una posición en la que puede diseñar un marco de evaluación más robusto y a priori de las aves playeras a lo largo de toda la ruta. Con este marco, será más fácil priorizar los dólares limitados para que los resultados de conservación sean lo más positivos posible.

4.
J Appl Ecol ; 59(3): 653-663, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35873077

RESUMO

Neotropical countries receive financing and effort from temperate nations to aid the conservation of migratory species that move between temperate and tropical regions. If allocated strategically, these resources could simultaneously contribute to other conservation initiatives. In this study, we use novel distribution maps to show how those resources could aid planning for the recovery of threatened resident vertebrates.Using eBird-based relative abundance estimates, we first identified areas with high richness of Neotropical migrant landbirds of conservation concern (23 species) during the stationary non-breeding period. Within these areas, we then identified threatened species richness, projected forest loss and conducted a prioritization for 1,261 red-listed vertebrates using Terrestrial Area-of-Habitat maps.Richness for migrants was greatest along a corridor from the Yucatan peninsula south to the northern Andes but also included south-west Mexico and Hispaniola. Protected areas account for 22% of this region while 21% is at risk of forest loss. Within this focal region for migrants, all four vertebrate groups showed hotspots of threatened species richness along the west and east Andean slopes. Taxa-specific hotspots included montane areas of southern Mexico and central Guatemala (amphibians/reptiles) and the entire east slope of the Colombian East Andes (mammals).Our prioritization highlighted several areas of importance for conservation due to high threatened species richness and projected forest loss including (a) the Pacific dry forests of south-west Mexico, (b) montane regions of northern Central America and (c) the west Andean slope of Colombia and Ecuador. At a landscape scale in southern Colombia, we show how conservation efforts for six Neotropical migrants could benefit 56 threatened residents that share a similar elevational range. Synthesis and applications. Funding and effort for migratory bird conservation also has potential to benefit threatened resident vertebrates in the Neotropics. Our study highlights how novel, high-resolution information on species distributions and risk of forest loss can be integrated to identify priority areas for the two groups at regional and landscape scales. The approach and data can be further modified for more specific goals, such as within-country initiatives.


Los países neotropicales reciben financiamiento y recursos esfuerzos de países templados para ayudar a la conservación de las aves migratorias que se mueven entre estas dos regiones. Si se asignan estratégicamente, estos recursos podrían beneficiar simultáneamente a otras iniciativas de conservación. En esta investigación, usamos novedosos mapas de distribución para mostrar cómo esos recursos podrían ayudar a planificar la conservación de especies residentes amenazadas.Utilizando estimaciones de abundancia de eBird, delineamos la Región Focal con la mayor riqueza de aves migratorias neotropicales de interés para la conservación durante el periodo invernal (23 especies). Dentro de esta región, determinamos la riqueza de especies residentes amenazadas, la proyección de pérdida de bosque, y realizamos una priorización para 1261 especies de vertebrados incluidos en la lista roja de la IUCN utilizando mapas del área de hábitat terrestre.En la Región Focal, la riqueza de aves migratorias fue mayor a lo largo de un corredor desde el sur de la península de Yucatán hasta el norte de los Andes, y en el suroeste de México y la isla La Española. Las áreas protegidas representan 22% de esta región mientras que el 21% está en riesgo de pérdida de bosque. Dentro de la Región Focal para las aves migratorias, todos los vertebrados residentes mostraron puntos de mayor riqueza de especies amenazadas en los Andes occidentales y orientales. Las regiones con mayor riqueza para taxones específicos incluyeron las montañas del sur de México y del centro de Guatemala (anfibios y reptiles) y la vertiente oriental de la cordillera oriental de Colombia (mamíferos).La priorización destacó varias áreas de importancia para la conservación debido a la alta riqueza de especies amenazadas y a la pérdida de bosque proyectada incluyendo 1) los bosques secos del Pacífico del suroeste de México, 2) las regiones montañosas del norte de Centroamérica y 3) la vertiente occidental de los Andes Occidental de Colombia y Ecuador. A escala del paisaje en el sur de Colombia, mostramos cómo los esfuerzos para la conservación de 6 aves migratorias podrían beneficiar a 56 especies residentes amenazadas que comparten un rango altitudinal similar. Síntesis y aplicaciones. La financiación y esfuerzos para la conservación de las aves migratorias tienen el potencial a beneficiar a los vertebrados residentes amenazados en el Neotrópico. Nuestro estudio resalta como se puede integrar información novedosa y de alta resolución acerca de la distribución de especies y el riesgo de pérdida de bosques para identificar áreas prioritarias para los dos grupos a escala regional y paisajística. El enfoque y los datos se pueden modificar para objetivos más específicos, como por ejemplo iniciativas dentro de cada país.

6.
Ecol Appl ; 30(3): e02056, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31837058

RESUMO

Information on species' distributions, abundances, and how they change over time is central to the study of the ecology and conservation of animal populations. This information is challenging to obtain at landscape scales across range-wide extents for two main reasons. First, landscape-scale processes that affect populations vary throughout the year and across species' ranges, requiring high-resolution, year-round data across broad, sometimes hemispheric, spatial extents. Second, while citizen science projects can collect data at these resolutions and extents, using these data requires appropriate analysis to address known sources of bias. Here, we present an analytical framework to address these challenges and generate year-round, range-wide distributional information using citizen science data. To illustrate this approach, we apply the framework to Wood Thrush (Hylocichla mustelina), a long-distance Neotropical migrant and species of conservation concern, using data from the citizen science project eBird. We estimate occurrence and abundance across a range of spatial scales throughout the annual cycle. Additionally, we generate intra-annual estimates of the range, intra-annual estimates of the associations between species and characteristics of the landscape, and interannual trends in abundance for breeding and non-breeding seasons. The range-wide population trajectories for Wood Thrush show a close correspondence between breeding and non-breeding seasons with steep declines between 2010 and 2013 followed by shallower rates of decline from 2013 to 2016. The breeding season range-wide population trajectory based on the independently collected and analyzed North American Breeding Bird Survey data also shows this pattern. The information provided here fills important knowledge gaps for Wood Thrush, especially during the less studied migration and non-breeding periods. More generally, the modeling framework presented here can be used to accurately capture landscape scale intra- and interannual distributional dynamics for broadly distributed, highly mobile species.


Assuntos
Ciência do Cidadão , Aves Canoras , Migração Animal , Animais , Ecologia , Dinâmica Populacional , Estações do Ano
7.
Rev. chil. neuropsicol. (En línea) ; 14(2): 14-17, dic. 2019. tab
Artigo em Espanhol | LILACS | ID: biblio-1102461

RESUMO

El presente artículo introduce un estudio cuantitativo en el que se compararon los desempeños neuropsicológicos ejecutivos en 20 adultos mayores con antecedentes de riesgo cardiovascular o ACV y sus pares sin dicha condición. Para dicho objetivo se empleó el tamizaje mini mental como criterio de inclusión en la muestra. Igualmente, la investigación indagó la correlación entre el nivel de rendimiento ejecutivo ante la batería neuropsicológica de funciones ejecutivas BANFE 2 y los factores de riesgo cardiovascular. Finalmente, los resultados indicaron que sujetos con historial de ACV presentaron un desempeño más bajo en las funciones ejecutivas orbito frontales y frontal anterior.


The following article introduces a quantitative study in which executive neuropsychological performances were compared in 20 older adults with a history of cardiovascular risk or stroke and their peers without such condition. Mini-mental screening was used as a criterion for inclusion in the sample. The research investigated the correlation between the level of executive performance in the neuropsychological battery of executive functions BANFE 2 and cardiovascular risk factors. Finally, the results indicated that subjects with a history of stroke presented a lower performance in executive functions at the orbitofrontal and frontal lobe.


Assuntos
Humanos , Masculino , Feminino , Idoso de 80 Anos ou mais , Doenças Cardiovasculares , Função Executiva/fisiologia , Fatores de Risco , Colômbia , Neuropsicologia
8.
Bioscience ; 69(3): 170-179, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30905970

RESUMO

Biodiversity is being lost at an unprecedented rate, and monitoring is crucial for understanding the causal drivers and assessing solutions. Most biodiversity monitoring data are collected by volunteers through citizen science projects, and often crucial information is lacking to account for the inevitable biases that observers introduce during data collection. We contend that citizen science projects intended to support biodiversity monitoring must gather information about the observation process as well as species occurrence. We illustrate this using eBird, a global citizen science project that collects information on bird occurrences as well as vital contextual information on the observation process while maintaining broad participation. Our fundamental argument is that regardless of what species are being monitored, when citizen science projects collect a small set of basic information about how participants make their observations, the scientific value of the data collected will be dramatically improved.

9.
Proc Natl Acad Sci U S A ; 115(47): 11982-11987, 2018 11 20.
Artigo em Inglês | MEDLINE | ID: mdl-30373825

RESUMO

Montane species worldwide are shifting upslope in response to recent temperature increases. These upslope shifts are predicted to lead to mountaintop extinctions of species that live only near mountain summits, but empirical examples of populations that have disappeared are sparse. We show that recent warming constitutes an "escalator to extinction" for birds on a remote Peruvian mountain-high-elevation species have declined in both range size and abundance, and several previously common mountaintop residents have disappeared from the local community. Our findings support projections that warming will likely drive widespread extirpations and extinctions of high-elevation taxa in the tropical Andes. Such climate change-driven mountaintop extirpations may be more likely in the tropics, where temperature seems to exert a stronger control on species' range limits than in the temperate zone. In contrast, we show that lowland bird species at our study site are expanding in range size as they shift their upper limits upslope and may thus benefit from climate change.


Assuntos
Distribuição Animal/fisiologia , Aves/fisiologia , Dinâmica Populacional/tendências , Altitude , Migração Animal/fisiologia , Animais , Biodiversidade , Mudança Climática , Conservação dos Recursos Naturais , Ecossistema , Extinção Biológica , Previsões , Comportamento de Retorno ao Território Vital , Peru , Temperatura , Clima Tropical
10.
Nat Ecol Evol ; 2(10): 1603-1609, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30224817

RESUMO

Avian migration is one of Earth's largest processes of biomass transport, involving billions of birds. We estimated continental biomass flows of nocturnal avian migrants across the contiguous United States using a network of 143 weather radars. We show that, relative to biomass leaving in autumn, proportionally more biomass returned in spring across the southern United States than across the northern United States. Neotropical migrants apparently achieved higher survival during the combined migration and non-breeding period, despite an average three- to fourfold longer migration distance, compared with a more northern assemblage of mostly temperate-wintering migrants. Additional mortality expected with longer migration distances was probably offset by high survival in the (sub)tropics. Nearctic-Neotropical migrants relying on a 'higher survivorship' life-history strategy may be particularly sensitive to variations in survival on the overwintering grounds, highlighting the need to identify and conserve important non-breeding habitats.


Assuntos
Migração Animal , Biomassa , Aves/fisiologia , Animais , Traços de História de Vida , Longevidade , Estações do Ano , Estados Unidos
11.
Rev. odontol. mex ; 21(3): 155-164, jul.-sep. 2017. tab, graf
Artigo em Espanhol | LILACS | ID: biblio-902732

RESUMO

RESUMEN: Objetivo: El propósito de este estudio fue comparar tres métodos de estimación de la edad dental (ED) con fines forenses. Material y métodos: Se seleccionaron 512 radiografías panorámicas de sujetos de Maracaibo, estado Zulia, Venezuela, de ambos sexos (272 hembras y 240 varones), con edades cronológicas (EC) entre 6-18 años. Se asignaron los estadios de maduración propuestos por Nolla, Moorrees et al y Demirjian et al a siete dientes mandibulares permanentes del lado izquierdo, la ED fue calculada de acuerdo con la metodología de cada autor. Se obtuvo la EC en la cual se observaron los diferentes estadios de maduración, así como las diferencias de media entre la EC y la ED estimada por cada método mediante un test de Student para muestras relacionadas. Resultados: En general, las hembras alcanzaron los estadios de maduración a edades más tempranas que los varones. Se evidenció en el total de la muestra, una sobreestimación de la edad para el método de Demirjian et al (-0.14 ± 1.45), mientras que para el de Nolla y Moorrees et al se observó una subestimación, esta subestimación fue mayor para el método de Moorrees et al (2.63 ± 2.09) que para el de Nolla (0.42 ± 1.38), siendo que las diferencias encontradas entre la EC y la ED fueron estadísticamente significativas. Conclusión: Se determinó que para el total de la muestra, el método de Demirjian et al fue el más preciso.


ABSTRACT: Objective: The purpose of the present study was to compare three methods for calculation of dental age (DA) to be used for forensic purposes. Material and methods: 512 panoramic X-rays of subjects of both genders living in Maracaibo, State of Zulia, Venezuela were selected (272 females, 240 males). Selected subjects were in the 6-18 years chronological age (CA) range. Maturation stages of Nolla, Moorrees et al and Demirjian et al were assigned to seven permanent teeth of the left side, and DA was calculated according to methodology of each author. CA was obtained where different stages of maturation were observed, as well as mean difference between DA and CA as calculated with each method were obtained with a t student test for related samples. Results: In general, females reached maturation stages at earlier ages than males. The total sample revealed age over-estimation for the Demirjian method (-0.14 ± 1.45), whereas, a sub-calculation was observed for the Nolla and Moorrees et al method. This under-estimation was greater for the Moorrees at al method (2.63 ± 2.09) when compared to Nolla method (0.42 ± 1.38) and differences between DA and CA were found to be statistically significant. Conclusion: In the total studied sample, it was determined that Demirjian et al method was the most accurate.

12.
Glob Chang Biol ; 23(12): 5284-5296, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28736872

RESUMO

Understanding the susceptibility of highly mobile taxa such as migratory birds to global change requires information on geographic patterns of occurrence across the annual cycle. Neotropical migrants that breed in North America and winter in Central America occur in high concentrations on their non-breeding grounds where they spend the majority of the year and where habitat loss has been associated with population declines. Here, we use eBird data to model weekly patterns of abundance and occurrence for 21 forest passerine species that winter in Central America. We estimate species' distributional dynamics across the annual cycle, which we use to determine how species are currently associated with public protected areas and projected changes in climate and land-use. The effects of global change on the non-breeding grounds is characterized by decreasing precipitation, especially during the summer, and the conversion of forest to cropland, grassland, or peri-urban. The effects of global change on the breeding grounds are characterized by increasing winter precipitation, higher temperatures, and the conversion of forest to peri-urban. During spring and autumn migration, species are projected to encounter higher temperatures, forests that have been converted to peri-urban, and increased precipitation during spring migration. Based on current distributional dynamics, susceptibility to global change is characterized by the loss of forested habitats on the non-breeding grounds, warming temperatures during migration and on the breeding grounds, and declining summer rainfall on the non-breeding grounds. Public protected areas with low and medium protection status are more prevalent on the non-breeding grounds, suggesting that management opportunities currently exist to mitigate near-term non-breeding habitat losses. These efforts would affect more individuals of more species during a longer period of the annual cycle, which may create additional opportunities for species to respond to changes in habitat or phenology that are likely to develop under climate change.


Assuntos
Migração Animal , Aves/fisiologia , Mudança Climática , Animais , Cruzamento , América Central , Demografia , Ecossistema , Florestas , América do Norte , Dinâmica Populacional , Chuva , Temperatura
13.
Proc Biol Sci ; 283(1840)2016 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-27708152

RESUMO

An emerging hypothesis in fire ecology is that pyrodiversity increases species diversity. We test whether pyrodiversity-defined as the standard deviation of fire severity-increases avian biodiversity at two spatial scales, and whether and how this relationship may change in the decade following fire. We use a dynamic Bayesian community model applied to a multi-year dataset of bird surveys at 1106 points sampled across 97 fires in montane California. Our results provide strong support for a positive relationship between pyrodiversity and bird diversity. This relationship interacts with time since fire, with pyrodiversity having a greater effect on biodiversity at 10 years post-fire than at 1 year post-fire. Immediately after fires, patches of differing burn severities hold similar bird communities, but over the ensuing decade, bird assemblages within patches of contrasting severities differentiate. When evaluated at the scale of individual fires, fires with a greater heterogeneity of burn severities hold substantially more species. High spatial heterogeneity in severity, sometimes called 'mixed-severity fire', is a natural part of wildfire regimes in western North America, but may be jeopardized by climate change and a legacy of fire suppression. Forest management that encourages mixed-severity fire may be critical for sustaining biodiversity across fire-prone landscapes.


Assuntos
Biodiversidade , Aves/classificação , Incêndios , Florestas , Animais , Teorema de Bayes , California , Mudança Climática
14.
Croat Med J ; 53(5): 423-31, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23100204

RESUMO

AIM: To carry out a deeper forensic and anthropological evaluation of the short tandem repeat (STR) D9S1120 in five Mestizo populations and eight Amerindian groups from Mexico. METHODS: We amplified the STR D9S1120 based on primers and conditions described by Phillips et al, followed by capillary electrophoresis in the genetic analyzer ABI Prism 310. Genotypes were analyzed with the GeneMapper ID software. In each population we estimated statistical parameters of forensic importance and Hardy-Weinberg equilibrium. Heterozygosity and FST-values were compared with those previously obtained with nine STRs of the Combined DNA Index System (CODIS-STRs). RESULTS: Amerindian and Mestizo populations showed high frequencies of the allele 9 and 16, respectively. Population structure analysis (AMOVA) showed a significant differentiation between Amerindian groups (FST=2.81%; P<0.0001), larger than between Mestizos (FST=0.44%; P=0.187). D9S1120 showed less genetic diversity but better population differentiation estimates than CODIS-STRs between Amerindian groups and between Amerindians and Mestizos, but not between Mestizo groups. CONCLUSION: This study evaluated the ability of D9S1120 to be used for human identification purposes and demonstrated its anthropological potential to differentiate Mestizos and Amerindian populations.


Assuntos
Variação Genética , Genética Populacional , Índios Norte-Americanos/genética , Repetições de Microssatélites/genética , Antropologia Forense , Amplificação de Genes , Frequência do Gene , Genótipo , Humanos , México
15.
Ecol Appl ; 22(6): 1718-32, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23092010

RESUMO

Species loss can lead to cascading effects on communities, including the disruption of ecological processes such as seed dispersal. The endangered 'Alala (Corvus hawaiiensis), the largest remaining species of native Hawaiian forest bird, was once common in mesic and dry forests on the Big Island of Hawai'i, but today it exists solely in captivity. Prior to its extinction in the wild, the 'Alala may have helped to establish and maintain native Hawaiian forest communities by dispersing seeds of a wide variety of native plants. In the absence of 'Alala, the structure and composition of Hawai'i's forests may be changing, and some large-fruited plants may be dispersal limited, persisting primarily as ecological anachronisms. We fed captive 'Alala a variety of native fruits, documented behaviors relating to seed dispersal, and measured the germination success of seeds that passed through the gut of 'Alala relative to the germination success of seeds in control groups. 'Alala ate and carried 14 native fruits and provided germination benefits to several species by ingesting their seeds. Our results suggest that some plants rely heavily on 'Alala for these services. In captivity, juvenile birds displayed seed dispersal behaviors more often than adult birds for most fruiting plants in our study. We introduced captive 'Alala to two large-fruited, dry-forest plants, not previously recorded as 'Alala food resources, but which may once have been part of their natural diet. The seed dispersal behavior that 'Alala displayed toward these species supports the inclusion of dry and mesic forests in 'Alala habitat restoration plans and adds weight to the idea that plant dispersal limitation may contribute to the rarity of these plants. Our study provides evidence that 'Alala have the capacity to play a vital role in maintaining the diversity of fruiting plants in native Hawaiian forests through seed dispersal and enhanced seed germination, thus adding greater urgency to efforts to restore 'Alala to their former range.


Assuntos
Corvos/fisiologia , Plantas/classificação , Sementes/fisiologia , Animais , Conservação dos Recursos Naturais , Demografia , Ecossistema , Monitoramento Ambiental , Comportamento Alimentar , Frutas , Havaí , Árvores
16.
Conserv Biol ; 25(3): 450-7, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21083762

RESUMO

The 2010 biodiversity target agreed by signatories to the Convention on Biological Diversity directed the attention of conservation professionals toward the development of indicators with which to measure changes in biological diversity at the global scale. We considered why global biodiversity indicators are needed, what characteristics successful global indicators have, and how existing indicators perform. Because monitoring could absorb a large proportion of funds available for conservation, we believe indicators should be linked explicitly to monitoring objectives and decisions about which monitoring schemes deserve funding should be informed by predictions of the value of such schemes to decision making. We suggest that raising awareness among the public and policy makers, auditing management actions, and informing policy choices are the most important global monitoring objectives. Using four well-developed indicators of biological diversity (extent of forests, coverage of protected areas, Living Planet Index, Red List Index) as examples, we analyzed the characteristics needed for indicators to meet these objectives. We recommend that conservation professionals improve on existing indicators by eliminating spatial biases in data availability, fill gaps in information about ecosystems other than forests, and improve understanding of the way indicators respond to policy changes. Monitoring is not an end in itself, and we believe it is vital that the ultimate objectives of global monitoring of biological diversity inform development of new indicators.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais/tendências , Animais , Espécies em Perigo de Extinção
17.
Ecol Appl ; 18(4): 838-46, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18536246

RESUMO

Population ecology research has long been focused on linking environmental features with the viability of populations. The majority of this work has largely been carried out in temperate systems and, until recently, has examined the effects of habitat fragmentation on survival. In contrast, we looked at the effect of forest fragmentation on apparent survival of individuals of the White-ruffed Manakin (Corapipo altera) in southern Costa Rica. Survival and recapture rates were estimated using mark-recapture analyses, based on capture histories from 1993 to 2006. We sampled four forest patches ranging in size from 0.9 to 25 ha, and four sites in the larger 227-ha Las Cruces Biological Station Forest Reserve (LCBSFR). We found a significant difference in annual adult apparent survival rates for individuals marked and recaptured in forest fragments vs. individuals marked and recaptured in the larger LCBSFR. Contrary to our expectation, survival and recapture probabilities did not differ between male and female manakins. Also, there was no support for the existence of annual variation in survival within each study site. Our results suggest that forest fragmentation is likely having an effect on population dynamics for the White-ruffed Manakin in this landscape. Therefore, populations that appear to be persisting in fragmented landscapes might still be at risk of local extinction, and conservation action for tropical birds should be aimed at identifying and reducing sources of adult mortality. Future studies in fragmentation effects on reproductive success and survival, across broad geographical scales, will be needed before it is possible to achieve a clear understanding of the effects of habitat fragmentation on populations for both tropical and temperate regions.


Assuntos
Ecossistema , Passeriformes , Animais , Costa Rica , Feminino , Masculino , Fatores Sexuais , Clima Tropical
18.
Mol Ecol Resour ; 8(1): 215-8, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21585760

RESUMO

We describe 15 polymorphic microsatellite loci from the white-ruffed manakin Corapipo altera, a common understory bird of Neotropical lowland and montane evergreen forests from eastern Honduras to northwestern Colombia. These markers were developed in order to assess population structure and genetic diversity in a fragmented landscape, and to study gene flow between forest fragments. Primers were tested on a population of 159 individuals from the Coto Brus region of southwestern Costa Rica. We found between four and 23 alleles per locus, and observed heterozygosities ranging from 0.23 to 0.93.

19.
Rev. colomb. reumatol ; 14(1): 11-22, ene. 2007. ilus
Artigo em Espanhol | LILACS | ID: lil-636747

RESUMO

Introducción: la presencia de anticuerpos antinucleares (ANAS) ha sido tradicionalmente asociada a enfermedades del tejido conectivo; su determinación se constituye en una importante herramienta en el diagnóstico de estas entidades. Para su evaluación, se han utilizado métodos de inmunofluoresencia (IFI) que emplean como sustrato las células Hep-2. En los últimos años, se han generado nuevos sustratos celulares a partir de la manipulación genética de las iniciales denominados Hep-2000®. Estas permiten la identificación del antígeno Ro de manera simultánea. La incorporación reciente de métodos enzimáticos para la lectura de la prueba, ha generado una nueva técnica llamada Colorzyme que permite el uso del microscopio de luz, constituyéndose en una alternativa económica y funcional en comparación con la IFI convencional. Objetivo: el presente estudio pretende establecer la capacidad para detectar ANAS en los sustratos: Hep-2 y Hep-2000® por las técnicas de IFI y Colorzyme, en un grupo de pacientes con Enfermedad del Tejido Conectivo no Diferenciada (ETCND). Adicionalmente comparó la detección del antígeno Ro en los sustratos Hep-2000® con los resultados obtenidos por la técnica de ENAS ELISA tradicional. Materiales y métodos: se analizaron 26 pacientes con ETCND a quienes se les determinó ANAS por las técnicas: Hep-2 IFI; Hep-2000® IFI; Hep-2000 Colorzyme y ENAS por ELISA Screening (con especificidad para los autoantígenos Sm, RNP, SS-A/Ro, SS-B/La, Scl-70 y Jo-1). Resultados: los resultados encontrados por las técnicas revelan un mayor rendimiento diagnóstico (ANAS positivos) en las células Hep-2000®: 23 (88%) por IFI y 21 (81%) Colorzyme, comparadas con 20 (76%) del sustrato Hep-2 IFI. Todos los patrones “clásicos” IFI estuvieron representados en la técnica de Hep-2 IFI; en la técnica de Hep-2000® IFI no se observó el patrón homogéneo, por Colorzyme no se observaron los patrones nucleolar ni el citoplasmático. En todas las técnicas la forma predominante de presentación fue el patrón moteado fino: 50% Colorzyme, 42,9 % para Hep-2000® IFI y 34,6% para Hep-2 IFI. En general se obtuvieron buenas correlaciones en los resultados entre las técnicas Hep-2000® IFI y la enzimática (r=0,74 p<0,000) con una concordancia 0,71 (Cohen K, p<0,000), mas no así con Hep-2 que fue de 0,21 (p<0,03). Las correlaciones entre los patrones de IFI (r=0,6 p<0,000) y las diluciones (r=0,75 p<0,000) fueron mejores entre los sustratos Hep-2000®, comparadas con las células Hep-2 (r=0,5 p<0,003). Para establecer la capacidad de identificación del autoantígeno Ro de las técnicas Hep-2000®, se compararon los resultados obtenidos con los de la técnica específica de ELISA para SSA-Ro. Las células Hep-2000® mostraron una sensibilidad del 66% por IFI y del 33% Colorzyme. Conclusiones: la utilización de células Hep-2 sigue siendo una buena alternativa para la determinación de ANAS. Sin embargo, las células Hep- 2000® pueden considerarse un sustrato útil y confiable en nuestro medio, tanto por color como IFI. La técnica por color facilita su realización al abolir el uso de IFI, recurso tecnológico escaso en muchas instituciones. Los resultados negativos para Ro deben ser interpretados con cautela pacientes con ETCND, en algunos de estos casos es posible se requiera de la confirmación por otros métodos.


Introduction: The presence of antinuclear antibodies (ANAS) has been traditionally associated to conective tissue diseases. and their determination is an important tool in the diagnose of these entities. In the last years the Cells Hep-2 has been used .in the Inmunofluoresencia technique (IFI),. New cellular sustratos has been generated by genetic manipulation, denominated Hep-2000®. These allow the identification of the antigen Ro in the same procedure. The recent incorporation of enzymatic methods for the reading of the test, has generated a new technique called Colorzyme, This allows the use of the microscope of light that become the procedure in an economical and functional alternative in comparison with the conventional IFI. Objective: The present study pretend to establish the capacity of detection of ANAS in sustratos: Hep-2 and Hep-2000® for IFI and Colorzyme, in a group of patients with No Differentiated Conective Tissue Disease (NDCTD). Additionally compares the detection of the antigen Ro in Hep-2000® cells and confront the results obtained by the ENAS-ELISA technique . Materials and methods: The presence of ANAS were analyzed in the serum of 26 patients with NDCTD by the techniques: Hep-2 IFI; Hep-2000® IFI; Hep-2000 Colorzyme® and ENAS for ELISA Screening (with specificity for the auto antigens Sm, RNP, SS-A/Ro, SS-B/La, Scl-70 and Jo-1). Results: Hep-2000®: demonstrated a better capacity in order to found ANAS: 23 (88%) for IFI and 21 (81%) for Colorzyme, compared with 20 (76%) of Hep-2 IFI. All the patterns «classic¼ IFI was represented in the Hep-2 cells IFI; Hep-2000 IFI the homogeneous pattern was not observed. In Colozyme tecnique the nucleolar and citoplasmic patron was not observed. In all the techniques the predominant form of presentation was the speckle-fine pattern: 50% Colorzyme, 42.9% for Hep-2000® IFI and 34.6% for Hep-2 IFI Good correlations were obtained in the results among the technique Hep-2000® IFI and the Colorzyme (r=0.74 p <0.000) but not in the Hep-2 IFI substrate: 0.21 (p <0.03). The correlations among the patterns of IFI (r=0.6 p <0.000) and the dilutions (r=0.75 p <0.000) were better among the Hep-2000® substrates, compared with the Hep-2 cells (r=0.5

Assuntos
Humanos , Células , Doenças do Tecido Conjuntivo Indiferenciado , Anticorpos Antinucleares
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