Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 690
Filtrar
Mais filtros

Intervalo de ano de publicação
1.
Conserv Biol ; 37(5): e14134, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37259595

RESUMO

Conservation of biodiversity relies heavily on protected areas but their role and effectiveness under a warming climate is still debated. We estimated the climate-driven changes in the temperature niche compositions of bird communities inside and outside protected areas in southern Canada. We hypothesized that communities inside protected areas include a higher proportion of cold-dwelling species than communities outside protected areas. We also hypothesized that communities shift to warm-dwelling species more slowly inside protected areas than outside. To study community changes, we used large-scale and long-term (1997-2019) data from the Breeding Bird Survey of Canada. To describe the temperature niche compositions of bird communities, we calculated the community temperature index (CTI) annually for each community inside and outside protected areas. Generally, warm-dwelling species dominated communities with high CTI values. We modeled temporal changes in CTI as a function of protection status with linear mixed-effect models. We also determined which species contributed most to the temporal changes in CTI with a jackknife approach. As anticipated, CTI was lower inside protected areas than outside. However, contrary to our expectation, CTI increased faster over time inside than outside protected areas and warm-dwelling species contributed most to CTI change inside protected areas. These results highlight the ubiquitous impacts of climate warming. Currently, protected areas can aid cold-dwelling species by providing habitat, but as the climate warms, the communities' temperature compositions inside protected areas quickly begin to resemble those outside protected areas, suggesting that protected areas delay the impacts of climate warming on cold-dwelling species.


Cambios en la composición del nicho térmico dentro y fuera de las áreas protegidas bajo el calentamiento climático Resumen La conservación de la biodiversidad depende mucho de las áreas protegidas, aunque todavía se debate su papel y efectividad bajo el calentamiento climático. Estimamos los cambios causados por el clima en la composición de los nichos térmicos de las comunidades de aves dentro y fuera de las áreas protegidas al sur de Canadá. Supusimos que las comunidades dentro de las áreas protegidas incluyen una proporción mayor de especies de zonas frías que las comunidades fuera de las áreas protegidas. También supusimos que las comunidades cambian a especies de zonas cálidas de forma más lenta dentro de las áreas protegidas que fuera de ellas. Usamos datos de gran escala y largo plazo (1997-2019) del Censo de Aves Reproductoras de Canadá para estudiar los cambios comunitarios. Calculamos el índice anual de temperatura comunitaria (ITC) para cada comunidad dentro y fuera de las áreas protegidas para describir las composiciones del nicho térmico de las comunidades de aves. En general, las especies de zonas cálidas dominaron las comunidades con valores altos del ITC. Simulamos los cambios temporales en el ITC como función del estado de protección mediante modelos lineales de efecto mixto. También determinamos cuáles especies contribuyen más a los cambios temporales en el ITC con un enfoque jackknife. Como lo anticipamos, el ITC fue menor dentro de las áreas protegidas que afuera. Sin embargo, contrario a nuestra hipótesis, el ITC incrementó más rápido con el tiempo dentro de las áreas protegidas y las especies de zonas cálidas contribuyeron más al cambio en el ITC también dentro de las áreas protegidas. Estos resultados resaltan el impacto universal del calentamiento climático. Actualmente, las áreas protegidas pueden auxiliar a las especies de zonas frías al proporcionarles hábitats, pero conforme la temperatura aumenta, las composiciones térmicas de las comunidades dentro de las áreas protegidas se asemejan rápidamente a aquellas fuera de las áreas protegidas, lo que sugiere que las áreas protegidas retrasan el impacto del calentamiento climático sobre las especies de zonas frías.


Assuntos
Mudança Climática , Conservação dos Recursos Naturais , Animais , Temperatura , Clima , Ecossistema , Biodiversidade , Aves
2.
Conserv Biol ; 36(3): e13857, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-34766374

RESUMO

A central tenet of landscape ecology is that mobile species depend on complementary habitats, which are insufficient in isolation, but combine to support animals through the full annual cycle. However, incorporating the dynamic needs of mobile species into conservation strategies remains a challenge, particularly in the context of climate adaptation planning. For cold-water fishes, it is widely assumed that maximum temperatures are limiting and that summer data alone can predict refugia and population persistence. We tested these assumptions in populations of redband rainbow trout (Oncorhynchus mykiss newberrii) in an arid basin, where the dominance of hot, hyperproductive water in summer emulates threats of climate change predicted for cold-water fish in other basins. We used telemetry to reveal seasonal patterns of movement and habitat use. Then, we compared contributions of hot and cool water to growth with empirical indicators of diet and condition (gut contents, weight-length ratios, electric phase angle, and stable isotope signatures) and a bioenergetics model. During summer, trout occurred only in cool tributaries or springs (<20 °C) and avoided Upper Klamath Lake (>25 °C). During spring and fall, ≥65% of trout migrated to the lake (5-50 km) to forage. Spring and fall growth (mean [SD] 0.58% per day [0.80%] and 0.34 per day [0.55%], respectively) compensated for a net loss of energy in cool summer refuges (-0.56% per day [0.55%]). In winter, ≥90% of trout returned to tributaries (25-150 km) to spawn. Thus, although perennially cool tributaries supported thermal refuge and spawning, foraging opportunities in the seasonally hot lake ultimately fueled these behaviors. Current approaches to climate adaptation would prioritize the tributaries for conservation but would devalue critical foraging habitat because the lake is unsuitable and unoccupied during summer. Our results empirically demonstrate that warm water can fuel cold-water fisheries and challenge the common practice of identifying refugia based only on summer conditions.


RESUMEN: Un principio central de la ecología de paisaje es que las especies ambulantes dependen de hábitats complementarios, los cuales son insuficientes en aislamiento, pero al combinarse mantienen a los animales durante el ciclo anual completo. Sin embargo, la incorporación de las necesidades dinámicas de las especies ambulantes dentro de las estrategias de conservación todavía es un reto, particularmente en el contexto de la planeación de la adaptación climática. Para los peces de agua fría, generalmente se asume que las temperaturas máximas son limitantes y que los datos estivales son suficientes para predecir refugios y la persistencia poblacional. Pusimos a prueba estas suposiciones en poblaciones de trucha arcoíris (Oncorhynchus mykiss newberrii) de una cuenca árida, en donde el dominio de aguas cálidas e hiperproductivas durante el verano emula las amenazas del cambio climático pronosticadas para los peces de agua fría en otras cuencas. Usamos telemetría para descubrir los patrones estacionales de movimiento y uso de hábitat. Después, comparamos las contribuciones que tienen las aguas cálidas y frías al crecimiento con indicadores empíricos de dieta y condición (contenidos intestinales, proporciones peso-longitud, ángulo de fase eléctrica y huellas de isotopos estables) y un modelo bioenergético. Durante el verano, las truchas sólo estuvieron presentes en manantiales o afluentes fríos (<20°C) y evitaron el Lago Klamath Superior (>25°C). Durante la primavera y el otoño, ≥65% de las truchas migraron al lago (5-50 km) para procurar alimento. El crecimiento durante la primavera y el otoño (media [SD] 0.58% día-1 [0.80%] y 0.34 día-1 [0.55%], respectivamente) compensaron la pérdida neta de energía en los refugios fríos durante el verano (-0.56% día-1 [0.55%]). En el invierno, ≥90% de las truchas regresaron a los afluentes (25-150 km) para desovar. Entonces, mientras que los afluentes perennemente fríos fomentaron los refugios termales y el desove, fueron las oportunidades de alimentación en el lago cálido estacional las que finalmente alentaron estos comportamientos. Las estrategias actuales de adaptación climática pondrían como prioridad de conservación a los afluentes, pero devaluarían el hábitat crítico de alimentación porque el lago está desocupado y no es apto durante el verano. Nuestros resultados demuestran empíricamente que las aguas cálidas pueden promover las pesquerías de aguas frías y desafiar la práctica común de identificar refugios basándose solamente en las condiciones estivales.


Assuntos
Conservação dos Recursos Naturais , Pesqueiros , Animais , Mudança Climática , Ecossistema , Temperatura , Truta , Água
3.
Conserv Biol ; 36(2): e13822, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34490662

RESUMO

Protected areas (PAs) are often implemented without consideration of already existing PAs, which is likely to cause an overrepresentation of certain biophysical conditions. We assessed the representativeness of the current PA network with regard to the world's biophysical conditions to highlight which conditions are underprotected and where these conditions are located. We overlaid terrestrial and marine PAs with information on biophysical conditions (e.g., temperature, precipitation, and elevation) and then quantified the percentage of area covered by the PA network. For 1 variable at a time in the terrestrial realm, high temperature, low precipitation, and medium and very high elevation were underrepresented. For the marine realm, low and medium sea surface temperature (SST), medium and high sea surface salinity (SSS), and the deep sea were underrepresented. Overall, protection was evenly distributed for elevation across the terrestrial realm and SST across the marine realm. For 2 variables at a time, cold and very dry terrestrial environments had mostly low protection, which was also the case for low SST and low and medium SSS across most depths for marine environments. Low protection occurred mostly in the Sahara and the Arabian Peninsula for the terrestrial realm and along the Tropic of Capricorn and toward the poles for the marine realm. Although biodiversity measures are of prime importance for the design of PA networks, highlighting biophysical gaps in current PAs adds a frequently overlooked perspective. These gaps may weaken the potential of PAs to conserve biodiversity. Thus, our results may provide useful insights for researchers, practitioners, and policy makers to establish a more comprehensive global PA network.


Las áreas protegidas (AP) son frecuentemente implementadas sin considerar las ya existentes, lo que probablemente ocasiona una sobrerrepresentación de ciertas condiciones biofísicas. Analizamos la representatividad de la red actual de AP con respecto a las condiciones biofísicas del mundo para resaltar que condiciones están subprotegidas y en dónde se encuentran localizadas. Superpusimos las AP terrestres y marinas con la información sobre las condiciones biofísicas (p. ej.: temperatura, precipitación y elevación) y luego cuantificamos el porcentaje de área cubierta por la red de AP. Para el análisis de una variable a la vez, en el ambito terrestre, la alta temperatura, baja precipitación y las elevaciones media y muy alta estuvieron subrepresentadas. Para el ambito marino, la baja y media temperatura de la superficie marina (TSM), la media y alta salinidad de la superficie marina (SSM) y el mar profundo estuvieron subrepresentados. En general, la protección para la elevación en el ambito terrestre y para la TSM en el ambito marino se distribuyó uniformemente. Para el análisis de dos variables a la vez, los ambientes terrestres fríos y muy secos tuvieron en su mayoría una baja protección, lo que también ocurrió para la baia TSM y la baja y media SSM en casi todas las profundidades de los entornos marinos. La baja protección para el ambito terrestre estuvo presente en su mayoría en el Sahara y en la Península Arábiga, y en el ambito marino, a lo largo del Trópico de Cáncer y hacia los polos. Aunque las medidas de biodiversidad son de suma importancia para el diseño de las redes de AP, resaltar los vacíos de información biofísica en las actuales AP añade una perspectiva que con frecuencia se ignora. Estos vacíos pueden debilitar el potencial que tienen las AP para conservar la biodiversidad. Por lo tanto, nuestros resultados pueden proporcionar información útil para que investigadores, profesionales y tomadores de decisiones establezcan una red mundial de AP más completa.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Biodiversidade
4.
Conserv Biol ; 35(3): 834-845, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33009673

RESUMO

Climate warming is driving changes in species distributions and community composition. Many species have a so-called climatic debt, that is, shifts in range lag behind shifts in temperature isoclines. Inside protected areas (PAs), community changes in response to climate warming can be facilitated by greater colonization rates by warm-dwelling species, but also mitigated by lowering extirpation rates of cold-dwelling species. An evaluation of the relative importance of colonization-extirpation processes is important to inform conservation strategies that aim for both climate debt reduction and species conservation. We assessed the colonization-extirpation dynamics involved in community changes in response to climate inside and outside PAs. To do so, we used 25 years of occurrence data of nonbreeding waterbirds in the western Palearctic (97 species, 7071 sites, 39 countries, 1993-2017). We used a community temperature index (CTI) framework based on species thermal affinities to investigate species turnover induced by temperature increase. We determined whether thermal community adjustment was associated with colonization by warm-dwelling species or extirpation of cold-dwelling species by modeling change in standard deviation of the CTI (CTISD ). Using linear mixed-effects models, we investigated whether communities in PAs had lower climatic debt and different patterns of community change than communities outside PAs. For CTI and CTISD combined, communities inside PAs had more species, higher colonization, lower extirpation, and lower climatic debt (16%) than communities outside PAs. Thus, our results suggest that PAs facilitate 2 independent processes that shape community dynamics and maintain biodiversity. The community adjustment was, however, not sufficiently fast to keep pace with the large temperature increases in the central and northeastern western Palearctic. Our results underline the potential of combining CTI and CTISD metrics to improve understanding of the colonization-extirpation patterns driven by climate warming.


Beneficios de las Áreas Protegidas para las Aves Acuáticas No Reproductoras que Están Ajustando su Distribución Debido al Calentamiento Climático Resumen El calentamiento climático está generando cambios en la distribución y en la composición comunitaria de las especies. Muchas de ellas tienen una deuda climática, es decir, los cambios en la distribución se atrasan con respecto a los cambios en las isoclinas térmicas. Dentro de las áreas protegidas (APs), los cambios comunitarios como respuesta al calentamiento climático pueden facilitarse mediante tasas mayores de colonización por especies de climas cálidos, pero también pueden mitigarse al reducir las tasas de extirpación de las especies de climas fríos. Se requiere una evaluación de la importancia relativa de los procesos de colonización-extirpación para orientar las estrategias de conservación que buscan la reducción de la deuda climática y la conservación de las especies. Analizamos las dinámicas de colonización-extirpación que participan en los cambios comunitarios como respuesta al clima dentro y fuera de las APs. Para realizar lo anterior, usamos datos tomados durante 25 años de la presencia de aves acuáticas no reproductoras en el Paleártico occidental (97 especies, 7,071 sitios, 39 países, 1993-2017). Usamos un marco de trabajo del índice de temperatura comunitaria (ITC) basado en las afinidades térmicas de las especies para así investigar la rotación de especies inducida por el incremento en la temperatura. Determinamos si el ajuste térmico en la comunidad estuvo asociado con la colonización por especies de climas cálidos o con la extirpación de especies de climas fríos al modelar el cambio mediante una desviación estándar del ITC (ITCDS ). Con los modelos lineales de efectos mixtos investigamos si las comunidades dentro de las APs tenían una deuda climática más baja y patrones diferentes de cambio comunitario que las comunidades localizadas fuera de las APs. Con la combinación del ITC y deL ITCDS , las comunidades dentro de las APs tuvieron más especies, una mayor colonización, una menor extirpación y una deuda climática más baja (16%) que las comunidades fuera de las APs. Por lo tanto, nuestros resultados sugieren que las APs facilitan dos procesos independientes que moldean las dinámicas comunitarias y mantienen la biodiversidad. Sin embargo, el ajuste comunitario no fue lo suficientemente rápido para mantener el paso de los grandes incrementos en la temperatura de las regiones central y noreste del Paleártico occidental. Nuestros resultados resaltan el potencial que tiene la combinación de las medidas del ITC y del ICTDS para mejorar el entendimiento de los patrones de colonización-extirpación causados por el calentamiento climático.


Assuntos
Mudança Climática , Conservação dos Recursos Naturais , Animais , Biodiversidade , Aves , Ecossistema , Temperatura
5.
Rev Argent Microbiol ; 53(3): 225-232, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33413969

RESUMO

The transmission of intestinal parasites is generally considered to be "mediated by the environment" which suggests that they are particularly sensitive to the changes that occur in it. The aim of the present study was to evaluate the environmental variables that act as risk factors for intestinal parasitosis in children and youths in Argentina. The association between environmental variables related to temperature, precipitation and soil and parasitosis found in children and youths from different provinces was evaluated, including land use/cover classes obtained from satellite images. Of the total population analyzed, 66.9% of the participants were parasitized. The total number of identified parasite species was 17 and the most prevalent were Blastocystis sp. (42.2%), Enterobius vermicularis (33.6%) and Giardia lamblia (17.0%). Infection by protozoa, and by G. lamblia in particular, was greater when the mean summer temperature was higher (OR=1.2 for both). Blastocystis sp. and geohelminths were greater due to an increase in isothermality (OR=1.1 and 1.2, respectively). The risk of infection with Ascaris lumbricoides was associated with an increase in the temperature in the wettest quarter (OR=1.2). Hookworm infection was associated with an increase in the normalized difference vegetation index (OR=32.5). Most of participants infected with hookworms lived in areas with abundant arboreal-shrubby and agropastoral use vegetation. The heterogeneous distribution of enteric parasites is indicative of the wide environmental variability of Argentina.


Assuntos
Giardia lamblia , Enteropatias Parasitárias , Parasitos , Adolescente , Animais , Argentina/epidemiologia , Criança , Fezes , Humanos , Enteropatias Parasitárias/epidemiologia , Prevalência
6.
Conserv Biol ; 34(4): 966-976, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-31868276

RESUMO

Although the impacts of climate and land-use changes on biodiversity have been widely documented, their joint effects remain poorly understood. We evaluated how nonbreeding waterbird communities adjust to climate warming along a gradient of land-use change. Using midwinter waterbird counts (132 species) at 164 major nonbreeding sites in 22 Mediterranean countries, we assessed the changes in species composition from 1991 to 2010, relative to thermal niche position and breadth, in response to regional and local winter temperature anomalies and conversion of natural habitats. We observed a low-level, nonsignificant community adjustment to the temperature increase where natural habitat conversion occurred. At the sites affected by natural habitat conversion, the relative increase of warm-dwelling species in response to climate warming was 6 times lower and the relative species decline was 3 times higher than in the sites without natural habitat conversion. We found no evidence of community adjustment to climate warming when natural habitat conversion was >5% over 15 years. This strong negative effect suggests an antagonistic interaction between climate warming and habitat change. These results underline the importance of habitat conservation in community adjustment to climate warming.


Efecto Antagonista de la Conversión de Hábitats Naturales sobre el Ajuste Comunitario ante el Calentamiento Climático en Aves Acuáticas No Reproductoras Resumen Aunque el impacto de los cambios del clima y del uso de suelo sobre la biodiversidad está ampliamente documentado, los efectos conjuntos de estos cambios todavía no están entendidos del todo. Evaluamos cómo las comunidades no reproductoras de aves acuáticas se ajustan al calentamiento climático a la par de un gradiente de cambio de uso de suelo. Usamos conteos de aves acuáticas (132 especies) realizados en pleno invierno en 164 sitios no reproductores importantes en 22 países mediterráneos, evaluamos los cambios en la composición entre 1991 y 2010 en relación a la posición termal y a la amplitud del nicho en respuesta a las anomalías en la temperatura invernal local y a la conversión de hábitats naturales. Observamos un ajuste comunitario no significativo de bajo nivel al incremento de la temperatura en los lugares en donde ocurrió la conversión del hábitat natural. En los sitios afectados por la conversión del hábitat natural, el incremento relativo de las especies de hábitats cálidos como respuesta al calentamiento climático fue seis veces más bajo y la declinación relativa de especies fue tres veces más alto que en los sitios sin conversión del hábitat natural. No encontramos evidencias del ajuste comunitario al calentamiento climático cuando la conversión del hábitat natural fue >5% durante 15 años. Este efecto negativo pronunciado sugiere una interacción antagonista entre el calentamiento climático y el cambio del hábitat. Estos resultados remarcan la importancia que la conservación del hábitat tiene para el ajuste comunitario ante el calentamiento climático.


Assuntos
Mudança Climática , Conservação dos Recursos Naturais , Biodiversidade , Clima , Ecossistema
7.
Conserv Biol ; 34(1): 194-206, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31216073

RESUMO

Stand structure develops with stand age. Old-growth forests with well-developed stand structure support many species. However, development rates of stand structure likely vary with climate and topography. We modeled structural development of 4 key stand variables and a composite old-growth index as functions of climatic and topographic covariates. We used a hierarchical Bayesian method for analysis of extensive snap-shot National Forest Inventory (NFI) data in Japan (n = 9244) to account for differences in stand age. Development rates of structural variables and the old-growth index exhibited curvilinear responses to environmental covariates. Flat sites were characterized by high rates of structural development. Approximately 150 years were generally required to attain high values (approximately 0.8) of the old-growth index. However, the predicted age to achieve specific values varied depending on environmental conditions. Spatial predictions highlighted regional variation in potential structural development rates. For example, sometimes there were differences of >100 years among sites, even in the same catchment, in attainment of a medium index value (0.5) after timber harvesting. The NFI data suggested that natural forests, especially old natural forests (>150 years), remain generally on unproductive ridges, steep slopes, or areas with low temperature and deep snow, where many structural variables show slow development rates. We suggest that maintenance and restoration of old natural forests on flat sites should be prioritized for conservation due to the likely rapid development of stand structure, although remaining natural forests on low-productivity sites are still important and should be protected.


Un Modelo Empírico Espacialmente Explícito de Procesos de Desarrollo Estructural en Bosques Naturales Basado en el Clima y la Topografía Resumen La estructura de un rodal se desarrolla con la edad. Los bosques maduros con una estructura bien desarrollada dan sustento a muchas especies. Sin embargo, las tasas de desarrollo de los rodales probablemente varían con el clima y la topografía. Modelamos el desarrollo estructural de 4 variables clave de un rodal y un índice de crecimiento antiguo compuesto como funciones de covariables climáticas y topográficas. Utilizamos un método bayesiano jerárquico para analizar datos (n = 9,244) en fotografías del inventario nacional forestal (INF) de Japón para entender las diferencias en la edad de los rodales. Las tasas de desarrollo de las variables estructurales y el índice de crecimiento antiguo mostraron respuestas curvilíneas a las covariables ambientales. Los sitios planos se caracterizaron por altas tasas de desarrollo estructural. Por lo general, se requerían 150 años para alcanzar valores altos (∼0.8) en el índice de crecimiento antiguo. Sin embargo, la edad prevista para alcanzar valores específicos varió dependiendo de las condiciones ambientales. Las predicciones espaciales pusieron de relieve la variación regional en las potenciales tasas de desarrollo estructural. Por ejemplo, a veces había diferencia de >100 años entre sitios, aun en la misma cuenca, en el consecución de un valor de índice medio (0.5) después de la cosecha de madera. Los datos de INF sugieren que los bosques naturales, especialmente los bosques maduros (>150 años) permanecen generalmente en crestas improductivas, pendientes pronunciadas o en áreas con baja temperatura y nieve profunda, donde muchas variables estructurales muestran tasas de desarrollo lentas. Sugerimos que el mantenimiento y la restauración de bosques naturales maduros en sitios planos deben priorizarse para conservación debido al probable desarrollo rápido de la estructura del rodal, aunque los bosques naturales restantes en sitios de baja productividad también son importantes y deben ser protegidos.


Assuntos
Conservação dos Recursos Naturais , Florestas , Teorema de Bayes
8.
Conserv Biol ; 31(2): 427-436, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-27488734

RESUMO

Survival and reproduction are the two primary life-history traits essential for species' persistence; however, the environmental conditions that support each of these traits may not be the same. Despite this, reproductive requirements are seldom considered when estimating species' potential distributions. We sought to examine potentially limiting environmental factors influencing the distribution of an oviparous reptile of conservation concern with respect to the species' survival and reproduction and to assess the implications of the species' predicted climatic constraints on current conservation practices. We used ecological niche modeling to predict the probability of environmental suitability for the alligator snapping turtle (Macrochelys temminckii). We built an annual climate model to examine survival and a nesting climate model to examine reproduction. We combined incubation temperature requirements, products of modeled soil temperature data, and our estimated distributions to determine whether embryonic development constrained the northern distribution of the species. Low annual precipitation constrained the western distribution of alligator snapping turtles, whereas the northern distribution was constrained by thermal requirements during embryonic development. Only a portion of the geographic range predicted to have a high probability of suitability for alligator snapping turtle survival was estimated to be capable of supporting successful embryonic development. Historic occurrence records suggest adult alligator snapping turtles can survive in regions with colder climes than those associated with consistent and successful production of offspring. Estimated egg-incubation requirements indicated that current reintroductions at the northern edge of the species' range are within reproductively viable environmental conditions. Our results highlight the importance of considering survival and reproduction when estimating species' ecological niches, implicating conservation plans, and benefits of incorporating physiological data when evaluating species' distributions.


Assuntos
Conservação dos Recursos Naturais , Estágios do Ciclo de Vida , Tartarugas , Animais , Ecologia , Temperatura
9.
Rev Argent Microbiol ; 48(1): 78-85, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26920121

RESUMO

Sorghum, which is consumed in Tunisia as human food, suffers from severe colonization by several toxigenic fungi and contamination by mycotoxins. The Tunisian climate is characterized by high temperature and humidity that stimulates mold proliferation and mycotoxin accumulation in foodstuffs. This study investigated the effects of temperature (15, 25 and 37°C), water activity (aw, between 0.85 and 0.99) and incubation time (7, 14, 21 and 28 d) on fungal growth and aflatoxin B1 (AFB1) production by three Aspergillus flavus isolates (8, 10 and 14) inoculated on sorghum grains. The Baranyi model was applied to identify the limits of growth and mycotoxin production. Maximum diameter growth rates were observed at 0.99 a(w) at 37°C for two of the isolates. The minimum aw needed for mycelial growth was 0.91 at 25 and 37°C. At 15°C, only isolate 8 grew at 0.99 a(w). Aflatoxin B1 accumulation could be avoided by storing sorghum at low water activity levels (≤0.91 a(w)). Aflatoxin production was not observed at 15°C. This is the first work on the effects of water activity and temperature on A. flavus growth and AFB1 production by A. flavus isolates on sorghum grains.


Assuntos
Aflatoxina B1/biossíntese , Aspergillus flavus/crescimento & desenvolvimento , Aspergillus flavus/metabolismo , Grão Comestível/microbiologia , Sementes/microbiologia , Sorghum/microbiologia , Aspergillus flavus/isolamento & purificação , Micologia/métodos , Temperatura , Fatores de Tempo , Água
10.
Environ Res ; 143(Pt B): 89-99, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26365038

RESUMO

An expansion of the distribution of Ostreopsis cf. ovata, a dinoflagellate which produces palytoxin-like compounds, has been reported in recent years. Economical and social interests are affected by blooms, as they are responsible for respiratory and skin problems in humans and may cause damage to marine organisms. In order to identify the most influential environmental factors that trigger proliferations of O. cf. ovata in the area of the adjacent shallow rocky coast of the Ebro Delta (NW Mediterranean Sea) a three-year survey was performed on the metaphytic microalgae community growing on the macrophytes Jania rubens and Corallina elongata. Small-size diatoms were more abundant than dinoflagellates; O. cf. ovata was identified as the only species present from the genus. Seawater temperature was the primary driver defining the ecological niche of O. cf. ovata. Freshwater and groundwater fluxes were more pronounced in southern than in northern sites, which may have resulted in a distinct O. cf. ovata spatial distribution, with the highest records of abundance and more frequent blooms in the north. In consequence, negative correlations between the abundance of O. cf. ovata and nitrate concentrations and significant positive correlation with salinity were observed. The temporal pattern of O. cf. ovata dynamics from mid-July to early-November is probably due to the fact that this species is observed only above a certain threshold temperature of seawater. Metaphytic cells of O. cf. ovata were smaller in the northern site than in the south, possibly as a result of an increase in cell division, coinciding with higher abundance, and this could be an indicator of favorable conditions. Toxicity in planktonic cells was negatively correlated with cell abundance in the water column, achieving maximum concentrations of 25pg. PLTX eqcell(-1).


Assuntos
Biota , Dinoflagellida/crescimento & desenvolvimento , Monitoramento Ambiental/métodos , Proliferação Nociva de Algas , Água do Mar/química , Acrilamidas/análise , Acrilamidas/toxicidade , Biota/efeitos dos fármacos , Venenos de Cnidários , Diatomáceas/efeitos dos fármacos , Diatomáceas/crescimento & desenvolvimento , Mar Mediterrâneo , Microalgas/efeitos dos fármacos , Microalgas/crescimento & desenvolvimento , Dinâmica Populacional , Análise de Componente Principal , Salinidade , Espanha , Temperatura , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
11.
Cir Esp ; 92(6): 415-20, 2014.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-24360251

RESUMO

BACKGROUND: This study analyses the relationship between the incidence of idiopathic spontaneous pneumothorax (ISP) and atmospheric pressure (AP). METHODS: A total of 288 cases of ISP were included, 229 men and 59 women. The AP of the day of diagnosis, of the 3 prior days and the monthly average was registered. The association between the incidence of ISP and AP was analyzed by calculating standardized incidence ratio (SIR) and Poisson regression. RESULTS: The AP on the day of admission (mean±standard deviation) (1,017.9±7 hectopascals [hPa]) was higher than the monthly average AP (1,016.9±4.1 hPa) (P=.005). There was a monthly distribution pattern of ISP with the highest incidence in the months of January, February and September and the lowest in April. When AP was less than 1,014 hPa, there were fewer cases registered than what would statistically have been expected (58/72 cases). In contrast, when the pressure was higher than 1,019 hPa, the registered cases were more than expected (109/82 cases) (SIR=1.25; 95% CI: 1.04 to 1.51). The risk of ISP increased 1.15 times (95% CI: 1.05 to 1.25, P=.001) for each hPa of AP, regardless of sex, age and monthly average AP. A dose-response relationship was observed, with progressive increases in risk (IRR=1.06 when the AP was 1,014-1016 hPa; 1.17 hPa when the AP was 1,016-1,019 hPa and 1.69 when AP was superior to 1,019 hPa) (P for trend=.089). CONCLUSION: The AP is a risk factor for the onset of idiopathic spontaneous pneumothorax.


Assuntos
Pressão Atmosférica , Pneumotórax/epidemiologia , Adulto , Feminino , Humanos , Incidência , Masculino , Pneumotórax/etiologia , Estudos Retrospectivos , Estações do Ano
12.
J Med Entomol ; 2024 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-39077840

RESUMO

Wolbachia pipientis (Hertig, 1936), also referred as Wolbachia, is a bacterium present across insect taxa, certain strains of which have been demonstrated to impact the fitness and capacity to transmit viruses in mosquitoes, particularly Aedes aegypti (Linnaeus, 1762). Most studies examine these impacts in limited sets of environmental regimes. Here we seek to understand the impacts of environmentally relevant conditions such as larval density, temperature, and their interaction on wAlbB-infected A. aegypti. Using a factorial design, we measured wAlbB stability (relative density, post-emergence in females, and in progeny), the ability for wAlbB to induce cytoplasmic incompatibility, and bacterial effects on mosquito fitness (fecundity, fertility, and body mass) and performance (adult survival and time to pupation) across 2 temperature regimes (fluctuating and constant) and 2 initial larval densities (low and high). Fluctuating daily regimes of temperature (27 to 40 °C) led to decreased post-emergence wAlbB density and increased wAlbB density in eggs compared to constant temperature (27 °C). An increased fecundity was found in wAlbB-carrying females reared at fluctuating temperatures compared to uninfected wild-type females. wAlbB-carrying adult females showed significantly increased survival than wild-type females. Contrarily, wAlbB-carrying adult males exhibited a significantly lower survival than wild-type males. We found differential effects of assessed treatments (Wolbachia infection status, temperature, and larval density) across mosquito sexes and life stages. Taken together, our results indicate that realistic conditions may not impact dramatically the stability of wAlbB infection in A. aegypti. Nonetheless, understanding the ecological consequence of A. aegypti-wAlbB interaction is complex due to life history tradeoffs under conditions faced by natural populations.

13.
Actas Urol Esp (Engl Ed) ; 48(1): 19-24, 2024.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-37356576

RESUMO

OBJECTIVE: To analyze the current information about laser safety in retrograde intrarenal surgery (RIRS), focusing on the two main laser technologies that we use in urology, the holmium:yttrium-aluminum-garnet (Ho:YAG) laser, and the thulium fiber laser (TFL). METHODS: Narrative overview of the most relevant articles published in MEDLINE and Scopus databases about this subject. RESULTS: TFL and Ho:YAG laser at similar settings (0.2 J/40 Hz) have similar volume-averaged temperature increase and the average heating rate increase proportionally to laser power, especially when high frequencies are used. Recent preclinical data, comparing both laser technologies at different laser settings, agreed that when the delivered energy increases in expenses of higher frequencies, the thermal damage increases too. Higher frequencies, despite of the rise of temperature in the irrigation medium, can cause accidental thermal lasering lesions. CONCLUSION: The use of low frequency settings and a proper irrigation is critical to avoid thermal injury in endoscopic laser lithotripsy. In addition, the use of laser safety eyeglasses is recommended in Ho:YAG and TFL ELL.


Assuntos
Lasers de Estado Sólido , Litotripsia a Laser , Urologia , Litotripsia a Laser/efeitos adversos , Lasers de Estado Sólido/uso terapêutico , Endoscopia , Túlio
14.
Med Intensiva (Engl Ed) ; 48(6): 341-355, 2024 06.
Artigo em Inglês | MEDLINE | ID: mdl-38493062

RESUMO

Temperature management has been used in patients with acute brain injury resulting from different conditions, such as post-cardiac arrest hypoxic-ischaemic insult, acute ischaemic stroke, and severe traumatic brain injury. However, current evidence offers inconsistent and often contradictory results regarding the clinical benefit of this therapeutic strategy on mortality and functional outcomes. Current guidelines have focused mainly on active prevention and treatment of fever, while therapeutic hypothermia (TH) has fallen into disuse, although doubts persist as to its effectiveness according to the method of application and appropriate patient selection. This narrative review presents the most relevant clinical evidence on the effects of TH in patients with acute neurological damage, and the pathophysiological concepts supporting its use.


Assuntos
Lesões Encefálicas , Hipotermia Induzida , Humanos , Hipotermia Induzida/métodos , Lesões Encefálicas/terapia , Lesões Encefálicas/complicações , Febre/etiologia , Febre/terapia , Lesões Encefálicas Traumáticas/terapia , Lesões Encefálicas Traumáticas/complicações , Hipóxia-Isquemia Encefálica/terapia
15.
Conserv Biol ; 27(5): 968-78, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23565966

RESUMO

Uncertainty associated with ecological forecasts has long been recognized, but forecast accuracy is rarely quantified. We evaluated how well data on 82 populations of 20 species of plants spanning 3 continents explained and predicted plant population dynamics. We parameterized stage-based matrix models with demographic data from individually marked plants and determined how well these models forecast population sizes observed at least 5 years into the future. Simple demographic models forecasted population dynamics poorly; only 40% of observed population sizes fell within our forecasts' 95% confidence limits. However, these models explained population dynamics during the years in which data were collected; observed changes in population size during the data-collection period were strongly positively correlated with population growth rate. Thus, these models are at least a sound way to quantify population status. Poor forecasts were not associated with the number of individual plants or years of data. We tested whether vital rates were density dependent and found both positive and negative density dependence. However, density dependence was not associated with forecast error. Forecast error was significantly associated with environmental differences between the data collection and forecast periods. To forecast population fates, more detailed models, such as those that project how environments are likely to change and how these changes will affect population dynamics, may be needed. Such detailed models are not always feasible. Thus, it may be wiser to make risk-averse decisions than to expect precise forecasts from models.


Assuntos
Conservação dos Recursos Naturais , Previsões , Fenômenos Fisiológicos Vegetais , Modelos Teóricos , Densidade Demográfica , Dinâmica Populacional/tendências
16.
Conserv Biol ; 27(4): 741-51, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23773091

RESUMO

Climate change is believed to be causing declines of ectothermic vertebrates, but there is little evidence that climatic conditions associated with declines have exceeded critical (i.e., acutely lethal) maxima or minima, and most relevant studies are correlative, anecdotal, or short-term (hours). We conducted an 11-week factorial experiment to examine the effects of temperature (22 °C or 27 °C), moisture (wet or dry), and atrazine (an herbicide; 0, 4, 40, 400 µg/L exposure as embryos and larvae) on the survival, growth, behavior, and foraging rates of postmetamorphic streamside salamanders (Ambystoma barbouri), a species of conservation concern. The tested climatic conditions were between the critical maxima and minima of streamside salamanders; thus, this experiment quantified the long-term effects of climate change within the noncritical range of this species. Despite a suite of behavioral adaptations to warm and dry conditions (e.g., burrowing, refuge use, huddling with conspecifics, and a reduction in activity), streamside salamanders exhibited significant loss of mass and significant mortality in all but the cool and moist conditions, which were closest to the climatic conditions in which they are most active in nature. A temperature of 27 °C represented a greater mortality risk than dry conditions; death occurred rapidly at this temperature and more gradually under cool and dry conditions. Foraging decreased under dry conditions, which suggests there were opportunity costs to water conservation. Exposure to the herbicide atrazine additively decreased water-conserving behaviors, foraging efficiency, mass, and time to death. Hence, the hypothesis that moderate climate change can cause population declines is even more plausible under scenarios with multiple stressors. These results suggest that climate change within the noncritical range of species and pollution may reduce individual performance by altering metabolic demands, hydration, and foraging effort and may facilitate population declines of amphibians and perhaps other ectothermic vertebrates.


Assuntos
Adaptação Biológica/fisiologia , Ambystoma/fisiologia , Mudança Climática , Herbicidas/toxicidade , Estresse Fisiológico/fisiologia , Temperatura , Água/análise , Animais , Atrazina , Comportamento Animal/efeitos dos fármacos , Comportamento Animal/fisiologia , Relação Dose-Resposta a Droga , Comportamento Exploratório/efeitos dos fármacos , Comportamento Exploratório/fisiologia , Kentucky , Funções Verossimilhança , Especificidade da Espécie , Análise de Sobrevida
17.
Med Clin (Barc) ; 160(8): 327-332, 2023 04 21.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-36257839

RESUMO

OBJECTIVES: Evaluating whether meteorological and geographical variables could be associated with the severity of COVID-19 in Spain. METHODS: An ecological study was performed to analyze the influence of meteorological and geographical factors in hospital admissions and deaths due to COVID-19 in the 52 provinces of Spain (24 coastal and 28 inland regions), during the first three pandemic waves. Medical and mortality data were collected from the CarlosIII Health Institute (ISCIII) and meteorological variables were requested to the Spanish State Meteorological Agency (AEMET). RESULTS: Regarding the diagnosed cases it is remarkable that the percentage of patients hospitalized for COVID-19 was lower in the coastal provinces than in the inland ones (8.7±2.6% vs. 11.5±2.6%; P=9.9×10-5). Furthermore, coastal regions registered a lower percentage of mortality than inland regions (2.0±0.6% vs. 3.1±0.8%; P=1.7×10-5). Mean air temperature was inversely correlated both with COVID-19 hospitalizations (Rho: -0.59; P=3.0×10-6) and mortality (Rho: -0.70; P=5.3×10-9). In those provinces with a mean air temperature <10°C mortality by COVID-19 was twice that of those with >16°C. Finally, we found an association between mortality and the location of the province (coastal/inland), altitude, patient age and the average air temperature; the latter was inversely and independently correlated with mortality (non-standardized ß coeff.: -0.24; 95%CI: -0.31 to -0.16; P=2.38×10-8). CONCLUSIONS: The average air temperature was inversely associated with COVID-19 mortality in our country during the first three waves of the pandemic.


Assuntos
COVID-19 , Humanos , COVID-19/epidemiologia , Espanha/epidemiologia , Conceitos Meteorológicos , Temperatura , Hospitalização
18.
Rev Int Androl ; 21(2): 100350, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36933371

RESUMO

INTRODUCTION: Human semen analysis must be performed after the liquefaction of the ejaculate. This takes place about 30min after ejaculation and samples must be maintained in the lab during this time. The temperatures for this incubation and the final analysis of motility are crucial but seldom taken into account. This study aims to examine the effect of these temperatures on various sperm parameters both manually (sperm count, motility, morphology, viability, chromatin condensation and maturation and DNA fragmentation) and CASA (kinematics and morphometrics, using an ISAS®v1 CASA-Mot and CASA-Morph systems, respectively) analyzed. METHODS: Seminal samples from thirteen donors were incubated for 10min at 37°C followed by additional 20min at either room temperature (RT, 23°C) or 37°C and then examined following WHO 2010 criteria. RESULTS: The data obtained show that there were no significant differences (P>0.05) in the subjective sperm quality parameters with incubation temperature. On the other hand, the head sperm morphometric parameters were significantly higher after room temperature incubation showing, in addition, lower ellipticity (P<0.05). Furthermore, kinematic parameters were evaluated both at RT and 37°C for the two incubation temperatures. In general, the four temperature combinations showed that kinematic parameters followed this order: RT-RT

Assuntos
Sêmen , Motilidade dos Espermatozoides , Humanos , Masculino , Temperatura , Fenômenos Biomecânicos , Espermatozoides , Análise do Sêmen/métodos
19.
Actas Urol Esp (Engl Ed) ; 47(3): 159-164, 2023 04.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-37013354

RESUMO

AIM: To measure the temperature dynamics at the renal surface and within the urinary tract when using Ho:YAG and Tm:YAG lasers for tissue ablation. MATERIALS AND METHODS: Porcine kidneys were used. Both types of lasers with different configurations and fiber sizes were used through a flexible ureteroscope. The temperature at the renal surface was recorded using a thermal camera while the intrarenal temperature was measured using two thermal probes, the first one at the ureteropelvic junction and the second one at the calyx used for lasering. Temperature was determined at 0.5-1-3-5 and 10 min. RESULTS: Recordings at the ureteropelvic junction and calyx revealed significant increases when using Tm:YAG with the 273 µm (10 W to 50 W) (p ≤ 0.02) and 550 µm (10 W) fiber (p = 0.04). With Ho:YAG there was a significant increase when using 273 µm (at 10 W and 20 W) (p ≤ 0.03) and 365 µm (10 W) fibers (p = 0.04). Regarding fiber size there was a significant difference when using Tm:YAG (at 20 W and 40 W) (p < 0.05). The thermal camera recorded a mean increase of 8 °C in the UPJ while the remaining areas of the kidney did not undergo significant changes. CONCLUSIONS: Temperature changes were greater when using the Ho:YAG laser with respect to Tm:YAG at similar power settings for tissue ablation. The greatest temperature increase was recorded at the UPJ from where the heat dissipated throughout the kidney.


Assuntos
Lasers de Estado Sólido , Suínos , Animais , Lasers de Estado Sólido/uso terapêutico , Temperatura , Túlio , Hólmio , Rim/cirurgia
20.
Hipertens Riesgo Vasc ; 40(3): 119-125, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37748946

RESUMO

BACKGROUND AND METHODOLOGY: Air pollutants have a significant impact on public health. The aim of the study was to find out the relationship between ambulatory blood pressure measured by 24-h ambulatory blood pressure monitoring (ABPM) and the atmospheric pollutants that are measured regularly (PM10, PM2.5, NO2 and SO2). An observational study of temporal and geographic measurements of individual patients (case-time series design) was carried out in Primary Care Centres and Hypertension Units in the Barcelona metropolitan area. We included 2888 hypertensive patients≥18 years old, untreated, with a first valid ABPM performed between 2005 and 2014 and with at least one air pollution station within a radius of <3km. RESULTS AND CONCLUSIONS: The mean age was 54.3 (SD 14.6) years. 50.1% were women and 16.9% of the sample were smokers. Mean 24-h blood pressure (BP) was 128.0 (12.7)/77.4 (9.7) mmHg. After adjusting for mean ambient temperature and different risk factors, a significant association was found between ambulatory diastolic BP (DBP) and PM10 concentrations the day before ABPM. For each increase of 10µg/m3 of PM10, an increase of 1.37mmHg 24-h DBP and 1.48mmHg daytime DBP was observed. No relationship was found between PM2.5, NO2 and SO2 and ambulatory BP, nor between any pollutant and clinical BP. The concentration of PM10 the day before the ABPM is significantly associated with an increase in 24-h DBP and daytime DBP.

SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa