Sediment delivery and lake dynamics in a Mediterranean mountain watershed: Human-climate interactions during the last millennium (El Tobar Lake record, Iberian Range, Spain)

Fernando Barreiro-Lostres; Erik Brown; Ana Moreno; Mario Morellón; Mark Abbott; Aubrey Hillman; Santiago Giralt; Blas Valero-Garcés

doi:10.1016/j.scitotenv.2015.06.123

Sediment delivery and lake dynamics in a Mediterranean mountain watershed: Human-climate interactions during the last millennium (El Tobar Lake record, Iberian Range, Spain)

Sci Total Environ. 2015 Nov 15:533:506-19. doi: 10.1016/j.scitotenv.2015.06.123. Epub 2015 Jul 15.

Authors

Fernando Barreiro-Lostres¹, Erik Brown², Ana Moreno³, Mario Morellón⁴, Mark Abbott⁵, Aubrey Hillman⁶, Santiago Giralt⁷, Blas Valero-Garcés⁸

Affiliations

¹ Dpt. of Geo-environmental Processes and Global Change, Pyrenean Institute of Ecology - CSIC, Spain. Electronic address: ferbalos@ipe.csic.es.
² Large Lakes Observatory and Department of Geological Sciences, University of Minnesota Duluth, Duluth, MN 55812, USA. Electronic address: etbrown@d.umn.edu.
³ Dpt. of Geo-environmental Processes and Global Change, Pyrenean Institute of Ecology - CSIC, Spain. Electronic address: amoreno@ipe.csic.es.
⁴ Instituto de Geociencias (CSIC, UCM), Calle José Antonio Nováis, 2, 3ª planta, 3b, Facultad de Ciencias Geológicas, Univ. Complutense, 28040 Madrid, Spain. Electronic address: mario.morellon@igeo.ucm-csic.es.
⁵ University of Pittsburgh, Geology and Planetary Science. 4107 O'Hara Street, Room 200, SRCC Building Pittsburgh, PA 15260-3332. USA. Electronic address: mabbott1@pitt.edu.
⁶ University of Pittsburgh, Geology and Planetary Science. 4107 O'Hara Street, Room 200, SRCC Building Pittsburgh, PA 15260-3332. USA. Electronic address: alh118@pitt.edu.
⁷ Institute of Earth Sciences Jaume Almera (ICTJA-CSIC), C/ Lluis Solé Sabaris s/n, Barcelona, E-08028 Spain. Electronic address: sgiralt@ictja.csic.es.
⁸ Dpt. of Geo-environmental Processes and Global Change, Pyrenean Institute of Ecology - CSIC, Spain. Electronic address: blas@ipe.csic.es.

PMID: 26186465
DOI: 10.1016/j.scitotenv.2015.06.123

Abstract

Land degradation and soil erosion are key environmental problems in Mediterranean mountains characterized by a long history of human occupation and a strong variability of hydrological regimes. To assess recent trends and evaluate climatic and anthropogenic impacts in these highly human modified watersheds we apply an historical approach combining lake sediment core multi-proxy analyses and reconstructions of past land uses to El Tobar Lake watershed, located in the Iberian Range (Central Spain). Four main periods of increased sediment delivery have been identified in the 8m long sediment sequence by their depositional and geochemical signatures. They took place around 16th, late 18th, mid 19th and early 20th centuries as a result of large land uses changes such as forest clearing, farming and grazing during periods of increasing population. In this highly human-modified watershed, positive synergies between human impact and humid periods led to increased sediment delivery periods. During the last millennium, the lake depositional and geochemical cycles recovered quickly after each sediment delivery event, showing strong resilience of the lacustrine system to watershed disturbance. Recent changes are characterized by large hydrological affections since 1967 with the construction of a canal from a nearby reservoir and a decreased in anthropic pressure in the watershed as rural areas were abandoned. The increased fresh water influx to the lake has caused large biological changes, leading to stronger meromictic conditions and higher organic matter accumulation while terrigenous inputs have decreased. Degradation processes in Iberian Range watersheds are strongly controlled by anthropic activities (land use changes, soil erosion) but modulated by climate-related hydrological changes (water availability, flood and runoff frequency).

Keywords: Geochemistry; Iberian Peninsula; Karstic lake; Land use changes; Late Quaternary; Palaeohydrology; Resilience; Sediment delivery.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Climate Change
Environmental Monitoring*
Geologic Sediments / analysis*
Lakes / chemistry*
Spain
Water Pollution / statistics & numerical data*