title: Statistical analyses of the results of 25 years of beach litter surveys on the south-eastern North Sea coast.
abstract: In the North Sea, the amount of litter present in the marine environment represents a severe environmental problem. In order to assess the magnitude of the problem and measure changes in abundance, the results of two beach litter monitoring programmes were compared and analysed for long-term trends applying multivariate techniques. Total beach litter pollution was persistently high. Spatial differences in litter abundance made it difficult to identify long-term trends: Partly more than 8000 litter items year(-1) were recorded on a 100 m long survey site on the island of Scharhörn, while the survey site on the beach on the island of Amrum revealed abundances lower by two orders of magnitude. Beach litter was dominated by plastic with mean proportions of 52%-91% of total beach litter. Non-parametric time series analyses detected many significant trends, which, however, did not show any systematic spatial patterns. Cluster analyses partly led to groupings of beaches according to their expositions to sources of litter, wind and currents. Surveys in short intervals of one to two weeks were found to give higher annual sums of beach litter than the quarterly surveys of the OSPAR method. Surveys at regular intervals of four weeks to five months would make monitoring results more reliable.
authors.affiliation: AquaEcology GmbH & Co. KG, Marie-Curie-Strasse 1, 26129 Oldenburg, Germany. Electronic address: mschulz@uos.de.
authors.forename: Marcus
authors.initials: M
authors.lastname: Schulz
authors.affiliation: Der Mellumrat e.V., Zum Jadebusen 179, 26316 Varel-Dangast, Germany. Electronic address: info@mellumrat.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Clemens
authors.affiliation: Naturschutzgesellschaft Schutzstation Wattenmeer e.V., Hafenstrasse 3, 25813 Husum, Germany. Electronic address: h.foerster@schutzstation-wattenmeer.de.
authors.forename: Harald
authors.initials: H
authors.lastname: Förster
authors.affiliation: Verein Jordsand zum Schutze der Seevögel und der Natur e.V., Bornkampsweg 35, 22926 Ahrensburg, Germany. Electronic address: Thorsten.Harder@jordsand.de.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Harder
authors.affiliation: Regional Agency of Coastal Protection, National Park, and Marine Protection of Schleswig-Holstein, Schlossgarten 1, 25832 Toenning, Germany. Electronic address: david.fleet@lkn.landsh.de.
authors.forename: David
authors.initials: D
authors.lastname: Fleet
authors.affiliation: Naturschutzgesellschaft Schutzstation Wattenmeer e.V., Hafenstrasse 3, 25813 Husum, Germany. Electronic address: s.gaus@schutzstation-wattenmeer.de.
authors.forename: Silvia
authors.initials: S
authors.lastname: Gaus
authors.affiliation: Verein Jordsand zum Schutze der Seevögel und der Natur e.V., Bornkampsweg 35, 22926 Ahrensburg, Germany. Electronic address: christel.grave@jordsand.de.
authors.forename: Christel
authors.initials: C
authors.lastname: Grave
authors.affiliation: Verein Jordsand zum Schutze der Seevögel und der Natur e.V., Bornkampsweg 35, 22926 Ahrensburg, Germany. Electronic address: imme.flegel@jordsand.de.
authors.forename: Imme
authors.initials: I
authors.lastname: Flegel
authors.affiliation: Verein Jordsand zum Schutze der Seevögel und der Natur e.V., Bornkampsweg 35, 22926 Ahrensburg, Germany. Electronic address: eckart.schrey@jordsand.de.
authors.forename: Eckart
authors.initials: E
authors.lastname: Schrey
authors.affiliation: Der Mellumrat e.V., Zum Jadebusen 179, 26316 Varel-Dangast, Germany. Electronic address: eikehartwig@gmx.de.
authors.forename: Eike
authors.initials: E
authors.lastname: Hartwig
mesh_terms: D001493:Bathing Beaches / Q000706:statistics & numerical data*; D016000:Cluster Analysis; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000032:analysis* / Q000145:classification; D005858:Germany; D009659:North Sea; D014866:Waste Products / Q000032:analysis* / Q000145:classification
chemical_list: D004785:Environmental Pollutants; D014866:Waste Products
keywords: Beach litter; Cluster analysis; Comparison; Southeastern North Sea; Survey method; Trend analysis