Organización y ajuste de sedimentos en un tramo torrencial de la cabecera del río Ijuez, Pirineo central español

Gómez-Villar, Amelia; Sanjuán, Yasmina; García‐Ruiz, José María; Nadal‐Romero, Estela; Álvarez-Martínez, Javier; Vadillo, José Arnáez; Muela, M. P. Serrano

doi:10.18172/cig.2566

Cited by 20 publications

(17 citation statements)

References 68 publications

(77 reference statements)

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“…Su datación mediante 14 C ha permitido situar cronológicamente la deforestación intencionada de buena parte del piso subalpino. Por último, en conos de deyección y cauces fluviales se ha medido el tamaño del sedimento grueso siguiendo el método de Wolman (1954) con el fin de relacionar la evolución del tamaño del sedimento a lo largo del curso con los aportes de sedimento desde las laderas (Martínez-Castroviejo & García-Ruiz, 1990;Gómez-Villar et al, 2014). En el caso de los conos de deyección de la Ribera de Biescas (Valle del Gállego) los resultados de estas mediciones se han utilizado como indicadores de la variabilidad espacial de la sedimentación y de la actividad torrencial (Gómez-Villar & García-Ruiz, 2000).…”

Section: Métodosunclassified

Los efectos geoecológicos del cambio global en el Pirineo Central español: una revisión a distintas escalas espaciales y temporales

García‐Ruiz¹,

López‐Moreno²,

Lasanta³

et al. 2015

Pirineos

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. Los efectos geoecológicos del cambio global en el Pirineo Central español: una revisión a distintas escalas espaciales y temporales. Pirineos, 170, e012. doi: http://dx.doi.org/10.3989/Pirineos.2015.170005 RESUMEN: Se revisan los efectos de la evolución del clima y los cambios de uso del suelo / cubierta vegetal en el Pirineo Central español a diferentes escalas espaciales y temporales. Los estudios paleoclimáticos, basados en análi-sis multiproxy de sedimentos lacustres, glaciares, espeleotémicos y registros dendrológicos, entre otros, han demostrado la ocurrencia de importantes fluctuaciones climáticas durante la deglaciación de finales del Pleistoceno Superior y durante el Holoceno, afectando a la distribución de la vegetación, la generación de escorrentía, la frecuencia de avenidas y las formas de organización del espacio por parte de las sociedades humanas, en particular durante el evento 8.2, la Edad del Bronce, la Anomalía Climática Medieval y la Pequeña Edad del Hielo. El estudio del impacto de las actividades humanas sobre la dinámica del paisaje en el último siglo y medio ha revelado cambios espectaculares en la estructura y distribución de la vegetación, tanto en el piso montano como en el subalpino y, consecuentemente, cambios en la generación de escorrentía, la intensidad de la erosión del suelo y las fuentes de sedimento, cualquiera que sea la escala espacial a la que se contempla el problema. De forma general puede afirmarse que a mediados del siglo xix se alcanza la máxima presión sobre el territorio, cultivándose todas las laderas posibles hasta una altitud aproximada de 1650 m s.n.m. y empleando frecuentemente el fuego para limitar la expansión de matorrales en zonas de pastos, lo que dio lugar a intensos procesos de erosión y degradación del suelo, y al desarrollo de ríos trenzados con una elevada torrencialidad. Posteriormente, el abandono de tierras de cultivo desde comienzos del siglo xx (y, en especial, desde la década de 1960) y el descenso de la presión ganadera han favorecido la revegetación de las antiguas áreas de cultivo y pastos bien por avance de formaciones naturales de matorral y bosque, bien por la reforestación artificial de extensas laderas, ascendiendo el treeline en el piso subalpino, en este último caso

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Section: Métodosunclassified

Los efectos geoecológicos del cambio global en el Pirineo Central español: una revisión a distintas escalas espaciales y temporales

García‐Ruiz¹,

López‐Moreno²,

Lasanta³

et al. 2015

Pirineos

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“…() applied the SHETRAN model to assess the possible consequences of deforestation on sediment delivery and transport; Beguería () investigated land cover changes, and the occurrence of shallow landslides and their accessibility to the Ijuez River; and Gómez‐Villar et al . () studied recent changes in sediment size and the channel morphology of the Ijuez River. The major geomorphic feature of the alluvial plain is the sequence of distinct sedimentary structures (fluvial terrace, large accumulation of debris flows and the active alluvial plain with a wandering channel).…”

Section: Introductionmentioning

confidence: 99%

“…The Ijuez River basin is an excellent example of land use changes in the southern Pyrenees and their effects on fluvial channel dynamics. Thus, Martínez-Castroviejo & García-Ruiz (1990) studied the sediment characteristics of the alluvial plain in relation to geomorphic activity in the headwater; Bathurst et al (2007) applied the SHETRAN model to assess the possible consequences of deforestation on sediment delivery and transport; Beguería (2006) investigated land cover changes, and the occurrence of shallow landslides and their accessibility to the Ijuez River; and Gómez-Villar et al (2014) studied recent changes in sediment size and the channel morphology of the Ijuez River. The major geomorphic feature of the alluvial plain is the sequence of distinct sedimentary structures (fluvial terrace, large accumulation of debris flows and the active alluvial plain with a wandering channel).…”

Section: Introductionmentioning

confidence: 99%

Linking Land Cover Changes in the Sub‐Alpine and Montane Belts to Changes in a Torrential River

et al. 2014

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Channel changes are the consequence of changes in sediment yield from the slopes and in the connectivity between slopes and channels because of distinct land use and climate impacts. In this study, we investigated the characteristics and evolution of a short reach in the headwater of the Ijnez River, central-southern Pyrenees. Assessment of a series of sedimentary and geomorphic structures confirmed major changes to the valley bottom, mainly related to changes in the intensity of human activity. The oldest sedimentary structure is a terrace level located 3 to 4 m above the current alluvia] plain. General deforestation, overgrazing and recurring fires in the montane belt (1100-1600 m a.s.1.) have led to increased soil erosion and connectivity, and to the triggering of debris flows that have been deposited on the fluvial terrace. Woody fragments from within the debris flows were dated using accelerator mass spectrometry "C radiocarbon techniques (AMS), yielding ages between 100 and 115cal years BP, which coincides with the period of maximum deforestation and human density in the Pyrenees. Depopulation and farmland abandonment since the beginning of the 20th century has resulted in generalized natural and artificial reforestation, a shrinkage of the eroded areas and a decline in connectivity between slopes and the channel. The most important consequence has been channel incision and narrowing, and the development of a sediment armour layer. Active sediment transport is continuing, although there has been a decrease in sediment yield from the slopes.

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“…However, reducing river sediment loads to very low levels may alter the fluvial dynamics and promote channel and bank erosion, as demonstrated in many rivers following natural forest development and afforestation on hillslopes. For instance, the Ijuez River in the Spanish Pyrenees has been affected by a 3‐m incision since the 1960s, as a consequence of land abandonment and general reforestation (Gómez‐Villar et al, ; Sanjuán et al, ) (Figure ). This is also the case for many mountain areas worldwide (García‐Ruiz & Lana‐Renault, ), in particular in the Mediterranean and Alpine basins (Liébault & Piégay, ; Piègay et al, ; Keesstra et al, ; Sanchis‐Ibor & Segura‐Beltrán, ; Lallias‐Tacon et al, ; Picco et al, ), and also in North America (Church & Slaymaker, ; Trimble, ).…”

Section: New Questions For An Old Problemmentioning

confidence: 99%

Ongoing and Emerging Questions in Water Erosion Studies

et al. 2016

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Soil erosion is a threat to food security, especially in regions where the area of arable land is shrinking dramatically because of soil degradation. Research on soil erosion expanded progressively throughout the 20th centu\ry, although a number of unresolved problems persist despite this issue being crucial for the environment and the welfare of society. Some basic unresolved issues, including the absence of a universally accepted definition of soil erosion and disagreement about how to measure it have contributed to a degree of scientific stagnation. Accurate prediction of the response of soils to disturbance is hampered by the dependence of the erosion process on the spatial scale involved, the time lag between the disturbance and the erosion response and the short periods for which data are typically available. We argue that devoting increased attention to the following environmental, demographic, political and societal issues will reinvigorate progress in the field. (i) The relationships between on‐site and off‐site consequences of soil erosion need to be elucidated if the economic and environmental costs are to be adequately assessed. (ii) Effective measures for soil conservation need to focus on spatial patterns of plant cover that reduce sediment connectivity, and most importantly on the relationships between hillslopes and sediment transfer in eroded channels. (iii) The scientific community must be able to identify early warning signs of critical transitions, if irreversible soil degradation is to be prevented. (iv) Consensus needs to be reached concerning the contribution of soil erosion to the carbon cycle. (v) The consequences of climate change on erosion and sediment transport should be investigated in depth. (vi) The general society needs to perceive soil erosion as a critical matter requiring an urgent response. Copyright © 2016 John Wiley & Sons, Ltd.

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Organización y ajuste de sedimentos en un tramo torrencial de la cabecera del río Ijuez, Pirineo central español

Abstract: ABSTRACT. The dynamics of the torrential upper reach of the

Cited by 20 publications

References 68 publications

Los efectos geoecológicos del cambio global en el Pirineo Central español: una revisión a distintas escalas espaciales y temporales

Los efectos geoecológicos del cambio global en el Pirineo Central español: una revisión a distintas escalas espaciales y temporales

Linking Land Cover Changes in the Sub‐Alpine and Montane Belts to Changes in a Torrential River

Ongoing and Emerging Questions in Water Erosion Studies

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