title: Exploring the potential for using210Pbexmeasurements within a re-sampling approach to document recent changes in soil redistribution rates within a small catchment in southern Italy.
abstract: In recent years, the fallout radionuclides caesium-137 (137Cs) and unsupported lead-210 (210Pbex)have been successfully used to document rates of soil erosion in many areas of the world, as an alternative to conventional measurements. By virtue of their different half-lives, these two radionuclides are capable of providing information related to different time windows.137Cs measurements are commonly used to generate information on mean annual erosion rates over the past ca. 50-60 years, whereas210Pbexmeasurements are able to provide information relating to a longer period of up to ca. 100 years. However, the time-integrated nature of the estimates of soil redistribution provided by137Cs and210Pbexmeasurements can be seen as a limitation, particularly when viewed in the context of global change and interest in the response of soil redistribution rates to contemporary climate change and land use change. Re-sampling techniques used with these two fallout radionuclides potentially provide a basis for providing information on recent changes in soil redistribution rates. By virtue of the effectively continuous fallout input, of210Pb, the response of the210Pbexinventory of a soil profile to changing soil redistribution rates and thus its potential for use with the re-sampling approach differs from that of137Cs. Its greater sensitivity to recent changes in soil redistribution rates suggests that210Pbexmay have advantages over137Cs for use in the re-sampling approach. The potential for using210Pbexmeasurements in re-sampling studies is explored further in this contribution. Attention focuses on a small (1.38 ha) forested catchment in southern Italy. The catchment was originally sampled for210Pbexmeasurements in 2001 and equivalent samples were collected from points very close to the original sampling points again in 2013. This made it possible to compare the estimates of mean annual erosion related to two different time windows. This comparison suggests that mean annual rates of net soil loss had increased during the period between the two sampling campaigns and that this increase was associated with a shift to an increased sediment delivery ratio. This change was consistent with independent information on likely changes in the sediment response of the study catchment provided by the available records of annual sediment yield and changes in the annual rainfall documented for the local area.
authors.affiliation: Dipartimento di Agraria, Università degli Studi Mediterranea, Località Feo di Vito, Reggio Calabria, Italy; Geography, College of Life and Environmental Sciences, University of Exeter, Amory Building, Rennes Drive, Exeter EX4 4RJ, UK. Electronic address: paolo.porto@unirc.it.
authors.forename: Paolo
authors.initials: P
authors.lastname: Porto
authors.affiliation: Geography, College of Life and Environmental Sciences, University of Exeter, Amory Building, Rennes Drive, Exeter EX4 4RJ, UK.
authors.forename: Desmond E
authors.initials: DE
authors.lastname: Walling
authors.affiliation: Dipartimento di Agraria, Università degli Studi Mediterranea, Località Feo di Vito, Reggio Calabria, Italy; Dipartimento DIBAF, Università della Tuscia, Viterbo, Italy.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Cogliandro
authors.affiliation: C.N.R.-Istituto per i Sistemi Agricoli e Forestali del Mediterraneo, Sezione Ecologia e Idrologia Forestale, Rende, CS, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Callegari
mesh_terms: D002588:Cesium Radioisotopes / Q000032:analysis; D019015:Geologic Sediments / Q000032:analysis / Q000737:chemistry*; D007558:Italy; D007856:Lead Radioisotopes / Q000032:analysis; D011834:Radiation Monitoring; D012990:Soil Pollutants, Radioactive / Q000032:analysis*
chemical_list: D002588:Cesium Radioisotopes; D007856:Lead Radioisotopes; D012990:Soil Pollutants, Radioactive
keywords: Erosion rates; Excess lead-210; Re-sampling approach; Sedimentation rates; Southern Italy