A number of experimental freshwater wetlands (150 m long × 75 m wide) with different ages since they were abandoned as rice fields, were used to analyze the prospects of multipurpose wetland restoration for such degraded areas. Nitrogen and phosphorus removal rate of the wetlands were determined monthly during the flooding season to estimate their efficiency as filters to remove nutrients from agricultural sewage. The number of wetland birds was recorded regularly to identify their habitat preferences. Both the temporal dynamics and changes in the spatial pattern of land use cover during the last 20 years were determined from aerial photographs and field analysis. All the wetlands appeared to be very efficient in the removal of nitrogen and phosphorus exported from rice fields. Usually 50–98% of the nitrogen and less than 50% of the soluble phosphorus were removed by the wetlands at any stage of restoration. Wetland birds preferred wetlands with intermediate plant cover for resting and sleeping activities better than rice fields and either very open wetlands or very dense ones with tall vegetation. Apart from the improvement in water quality and the restoration of natural habitats, restoration of wetland belts around lagoons will increase spatial heterogeneity and diversity of the landscape.
Tras la retirada de los hielos glaciares del Cuaternario, los abetos se replegaron hacia el norte o ascendieron en altitud hacia las montañas. Escindido del tronco común del abeto primigenio, Abies pinsapo persiste como especie relicta y endémica de la Serranía de Ronda, y una de las reliquias más meridionales de la aciculisilva. En este trabajo, desarrollamos un ensamblaje de modelos de nicho ecológico del pinsapo calibrados con datos actuales y proyectados hasta el horizonte 2100 según los escenarios previstos por el IPCC (AR5) regionalizados para el área de estudio. Nuestros modelos estimaron una drástica reducción de la distribución potencial de la especie en el área de estudio, incluso la desaparición del espacio ecológico del pinsapo en el peor de los escenarios.
El 11 de marzo de 2020, la Organización Mundial de la Salud (OMS) declaró pandemia global el brote de la enfermedad COVID-19, producida por el nuevo coronavirus SARS CoV-2. En este artículo se efectúa una revisión de las contribuciones científicas publicadas hasta la fecha que relacionan las condiciones atmosféricas con la distribución del SARS CoV-2. La mayor parte de ellas concluyen que existe cierta influencia del tiempo atmosférico y/o el clima en la distribución y el progreso de la COVID-19. En concreto, un ambiente fresco y seco, en el contexto de un clima mesotérmico, parece el más idóneo para la expansión del SARS CoV-2. Sin embargo, un número significativo de estudios revisados adolece de diseños de investigación inadecuados, lo que hace muy difícil aislar de forma fehaciente el efecto genuino de las condiciones atmosféricas en la propagación de la enfermedad de otros efectos, incluidos los posibles artefactos derivados de la prevalencia observada, la dependencia espacial y temporal de los datos y la propia geografía humana: conectividad geográfica, movilidad, sistema sanitario, etc. Se concluye que sólo existen indicios, no evidencia, de que las condiciones atmosféricas pueden llegar a explicar una fracción muy limitada de la dinámica espaciotemporal del SARS CoV-2.
The litter bag technique was used to study leaf decomposition in the large forested eutrophic (160.9 μmol l–1 DIN, 1.7 μmol l–1 SRP) Ebro river and in the forested Sènia (12.8 μmol l–1 DIN, 0.7 μmol l–1 RSP). Air dried leaves (3g) of Phragmites australis were used in both watercourses while Populus alba leaves were studied in the Ebro river only, and Populus nigra leaves and a submerged rooted macrophyte (stems and leaves), Potamogeton coloratus, were studied only in the Sènia stream. Litter bags of 100 μm and 1 mm mesh size were collected on days 0, 3, 15, 30, 90 and 120 and 5 mm mesh bags were sampled once after 30 days. Macroinvertebrates inside the leaf bags were retrieved and ash free dry weight and carbon and nitrogen contents of the remaining detritus were determined. Litter decomposition rates, k, were estimated using a simple exponential model. No significant differences in decomposition rates were observed between 100 μm and 1 mm mesh bags. In 100 μm litter bags, decomposition of P. nigra leaves from the Sènia stream (0.0104 day–1) was faster than that of P. alba leaves from the Ebro river (0.0049 day–1) (ANCOVA, p < 10–5). The decomposition rate of P. australis was higher in the Ebro river (0.009 ± 0.002 day–1) than in the Sènia stream (0.0056 ± 0.0004 day–1) for the first 30 days of decomposition, but no differences were observed from day 30 onwards. The number of macroinvertebrates increased over time and were mainly collectors‐gatherers of the genus Chironomus. Percentage of detritus nitrogen increased in litter that had initially high C/N ratios (28.7 in P. alba and 64.7 in P. nigra) and decreased when initial C/N ratios were low (12.6 and 14.6 for P. australis from the Sènia and Ebro river respectively).
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