jueves, 28 de abril de 2016

Miguel Delibes, eterno recuerdo

Miguel Delibes es, además de un referente literario, un referente medioambiental. Por eso sentimos tanto su fallecimiento, y nos reconfortamos releyendo sus libros y escritos. La noticia ahora es la finalización de las tareas de digitalización de todos sus documentos, por parte de la fundación que lleva su nombre. Una excelente noticia, sin duda.

Aquí os dejamos el enlace a la noticia aparecida en El País:

La autobiografía en documentos de Miguel Delibes, a golpe de clic

martes, 19 de abril de 2016

El Pisuerga con aguas altas

En estos días, los ríos de la cuenca del Duero llevan caudales bastante elevados, y muchos embalses están al 90 % de su capacidad.

Aquí os dejamos algunas fotos del Pisuerga a su paso por Valladolid, un paisaje urbano fluvial con aguas altas.

Fotos: Nuria Mongil (Flash-ion)

viernes, 8 de abril de 2016

Rejuvenating arid badlands: from barren slopes to living forest in 80 years

A reforestation project has revitalised its surroundings just 80 years after its inception. In the late 1920s, the Saldaña badlands in northern Spain were a barren region, with a thin layer of intensely weathered soil, and only 5% vegetation cover. Now that cover has increased dramatically to 87%, the soil quality is improving, and the water flow in the area has stabilised, bringing greater environmental security to the local community.

Badlands’ are a geological term for dry, eroded terrain, often featuring steep slopes, which are associated with landslides, high rates of sediment disposal, minimal vegetation and concentrated runoffs that lead to flash flooding. However, the Saldaña badlands were not always so degraded — in this case, it was not geological processes that made the terrain barren, but the cumulative impact of at least 18 centuries of human activity. 

This recently published study of this region, which was supported in part by the European Erasmus Mundus 17 Programme, analysed historical documents, maps, photos, and video of the 3.17 km2 area to create an account of how the badlands came to be, and conducted field analyses of the soil quality, vegetation cover and erosive processes to help determine the success of the reforestation project that started as recently as the 1930s.

Evidence suggests human presence on the landscape began around 12 000 years ago, but increased substantially during the time of the Roman Empire. Over the centuries, the combined pressures of war and agriculture led to intensive deforestation of the original forests. By 1472, populations downstream noted the negative effect that deforestation had on the quality of their water supply, but the situation continued to get worse, and by 1751, the slopes were described as a ‘degraded mountain’.

In 1928, the forest restoration project conducted by the forest engineer José Mª Ayerbe was initiated. Between 1932 and 1936, 3 000 trees were planted per hectare, including Scots Pine (Pinus sylvestris), elm (Ulmus campestris) and acacia (Robinia pseudoacacia) species, and hundreds of check dams (small temporary structures across water channels, used to slow the water flow) and wattle fences (a traditional technique that weaves small branches between large sticks) were constructed to help slow the movement of water and sediment.

The first major socio-economic success of the project was acknowledged in the early 1960s. The Saldaña-Osorno road was frequently blocked by mud flows and landslides during heavy rains in the past, but the restoration 
project put a halt to these disruptive events. Further restoration work was carried out on the land in 1963.

Desk and field analyses show that, since the turn of the century, the changes in the Saldaña badlands have 
produced substantial benefits. Forest vegetation now covers nearly the whole area, and evidence of soil 
regeneration is indicated by an increase in organic matter from leaf litter increased soil moisture, and the 
presence of species such as earthworms and fungal mycelium. The researchers found that sediment yield 
from the land diminished by three orders of magnitude compared with the 1940s, which helps to keep the 
nearby Carrión River free of suspended mud and silt. The rate at which water is absorbed into the ground 
is also 43 times greater on the forested slopes than bare slopes, greatly reducing the risks of flash flooding.

In addition, the biodiversity of the badlands is increasing. Species which can be found in established 
habitats of the region are now returning, including Pyrenean oak (Quercus pyrenaica), a local variety 
of wild peony (Paeonia broteroi), and the edible mushroom, saffron milk cap (Lactarius deliciosus). 
Although the landscape has shown dramatic results in its overall regeneration, analysis of the soil 
suggests that the recovery is not yet complete in terms of the evolution of the soil structure. Therefore 
pH, bulk density and erodibility of soils sampled from the vegetated areas are not significantly 
different than soils from the degraded areas. However, vegetation cover, leaf litter and check dams 
in the restored areas compensate for this and have arrested the most severe erosion processes.

Overall, the main objectives of the original restoration project seem to have been 
achieved. In under a hundred years, mass erosive processes have been drastically reduced, 
as well as their major consequences, such as landslides and mudflows. The researchers 
suggest that other landscapes with similar problems could be recovered in a similar way.

Source: Navarro Hevia, 
J., Carlos de Araújo, J. 
& Mongil Manso, J. 
(2014). Assessment of 80 
years of ancient-badlands 
restoration in Saldaña, 
Spain. Earth Surface 
Processes and Landforms 
39: 1563-1575. DOI 

Soil and water: a larger-scale perspective

Science for Environment Policy (2015) Soil and Water: a larger-scale perspective. Thematic Issue 52. Issue produced for the European Commission DG Environment by the Science Communication Unit, UWE, Bristol.