Linking land cover changes in the sub-alpine and montane belts to changes in a torrential river

  1. Sanjuán, Y. 1
  2. Gómez-Villar, A. 2
  3. Nadal-Romero, E. 3
  4. Álvarez-Martínez, J. 4
  5. Arnáez, J. 5
  6. Serrano-Muela, M.P. 1
  7. Rubiales, J.M. 6
  8. González-Sampériz, P. 1
  9. García-Ruiz, J.M. 1
  1. 1 Instituto Pirenaico de Ecología
    info

    Instituto Pirenaico de Ecología

    Zaragoza, España

    ROR https://ror.org/039ssy097

  2. 2 Universidad de León
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    Universidad de León

    León, España

    ROR https://ror.org/02tzt0b78

  3. 3 Universidad de Zaragoza
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    Universidad de Zaragoza

    Zaragoza, España

    ROR https://ror.org/012a91z28

  4. 4 Universidad de Valladolid
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    Universidad de Valladolid

    Valladolid, España

    ROR https://ror.org/01fvbaw18

  5. 5 Universidad de La Rioja
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    Universidad de La Rioja

    Logroño, España

    ROR https://ror.org/0553yr311

  6. 6 Universidad Politécnica de Madrid
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    Universidad Politécnica de Madrid

    Madrid, España

    ROR https://ror.org/03n6nwv02

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Revista:
Land Degradation and Development

ISSN: 1085-3278

Año de publicación: 2016

Volumen: 27

Número: 2

Páginas: 179-189

Tipo: Artículo

DOI: 10.1002/LDR.2294 SCOPUS: 2-s2.0-84957657057 WoS: WOS:000370151700008 GOOGLE SCHOLAR

Otras publicaciones en: Land Degradation and Development

Objetivos de desarrollo sostenible

Resumen

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 Ijuez 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 4m above the current alluvial plain. General deforestation, overgrazing and recurring fires in the montane belt (1100-1600ma.s.l.) 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 14C 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. © 2014 John Wiley & Sons, Ltd.