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.

No abstract

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.

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).

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.

This paper addresses the effects of atmospheric conditions on the spread of the SARS-CoV-2 coronavirus and its associated disease, COVID-19. We assess the limitations of bioclimatic correlative models to explain the geographic distribution of SARS-CoV-2 in the context of medical geography. There is a broad consensus that the global distribution of COVID-19 is not random but conditioned by environmental drivers. However, as the COVID-19 distribution becomes global, including tropical climates, the evidence reveals that atmospheric conditions explain, at most, only a limited amount of the space-time dynamics of SARS-CoV-2. The usefulness of approaches based on bioclimatic envelopes is in question since the dominant route for the spread of COVID-19 seems to be the anthroposphere's non-stationary environment. There is a need to clarify further the role of different transmission routes at multiple scales and outdoor and indoor environments beyond bioclimatic envelopes. At this time, the possible influence of the weather in COVID-19 spread is not sufficient to be taken into account in public health policies. Until reliable bioclimatic envelopes of SARS-CoV-2, if any, are found, caution should be exercised when reporting, as this could have unforeseen consequences, mainly when conclusions are based on interim results that have not been subjected to peer review.

No abstract

The spatial variability of plant organic matter processing was studied experimentally in a shallow coastal lagoon (Tancada lagoon, average depth: 37 cm, area: 1.8 km 2 ) in the Ebro River Delta (NE Spain). To determine the effect of hydrology and sediment characteristics on plant organic matter processing, leaves of Phragmites australis at the end of its vegetative cycle and whole plants of Ruppia cirrhosa (PETAGNA) GRANDE, just abscised, were enclosed in litter bags. Two different mesh sizes (100 µm and 2 mm) were used to study the effect of macroinvertebrates on decomposition. The bags were placed in the water column and approximately 15 cm above the sediment at 6 different locations in the lagoon. The experiment was performed twice, in autumn-winter and spring-summer. The effect of macroinvertebrates on decomposition rate was not significant in Tancada lagoon. Breakdown rates showed spatial differences only in spring-summer. In the autumn-winter experiment, the effect of strong wind masked the effects of environmental variables and hydrology on decomposition rate. In the spring-summer experiment, characterised by high stability of the water column, dissolved inorganic nitrogen (DIN) concentration in the water column and organic matter in the sediment were the main factors determining the variability of organic matter processing. A positive relationship was calculated between P. australis decomposition rate and dissolved inorganic nitrogen in spring-summer (r 2 = 0.92, p < 0.001).