title: Least Disturbed Condition for European Mediterranean rivers.
abstract: The present report describes a three-step approach that was used to characterize and define thresholds for the Least Disturbed Condition in Mediterranean streams of four different types, regarding organic pollution and nutrients, hydrological and morphological alterations, and land use. For this purpose, a common database composed of national reference sites (929 records) from seven countries, sampled for invertebrates, diatoms and macrophytes was used. The analyses of reference sites showed that small (catchment <100 km(2)) siliceous and non-siliceous streams were mainly affected by channelization, bank alteration and hydropeaking. Medium-sized siliceous rivers were the most affected by stressors: 25-43% of the samples showed at least slight alterations regarding channelization, connectivity, upstream dam influence, hydropeaking and degradation of riparian vegetation. Temporary streams were the least affected by hydromorphological changes, but they were nevertheless affected by alterations in riparian vegetation. There were no major differences between all permanent stream types regarding water quality, but temporary streams showed lower values for oxygenation (DO) and wider ranges for other variables, such as nitrates. A lower threshold value for DO (60%) was determined for this stream type and can be attributed to the streams' natural characteristics. For all other river types, common limits were found for the remaining variables (ammonium, nitrate, phosphate, total P, % of artificial areas, % of intensive and extensive agriculture, % of semi-natural areas in the catchment). These values were then used to select the list of reference sites. The biological communities were characterized, revealing the existence of nine groups of Mediterranean invertebrate communities, six for diatoms and five for macrophytes: each group was characterized by specific indicator taxa that highlighted the differences between groups.
authors.affiliation: Institute of Marine Research, IMAR-CMA, Dept. of Life Sciences, University of Coimbra, Portugal. Electronic address: mjf@ci.uc.pt.
authors.forename: M J
authors.initials: MJ
authors.lastname: Feio
authors.affiliation: Universidade Técnica de Lisboa, Instituto Superior de Agronomia, Centro de Estudos Florestais, Portugal.
authors.forename: F C
authors.initials: FC
authors.lastname: Aguiar
authors.affiliation: Department of Biology and GeoBioTec, University of Aveiro, Portugal.
authors.forename: S F P
authors.initials: SF
authors.lastname: Almeida
authors.affiliation: Portuguese Environmental Agency (APA, I.P.), Portugal.
authors.forename: J
authors.initials: J
authors.lastname: Ferreira
authors.affiliation: Universidade Técnica de Lisboa, Instituto Superior de Agronomia, Centro de Estudos Florestais, Portugal.
authors.forename: M T
authors.initials: MT
authors.lastname: Ferreira
authors.affiliation: Department of Biology and GeoBioTec, University of Aveiro, Portugal.
authors.forename: C
authors.initials: C
authors.lastname: Elias
authors.affiliation: Institute of Marine Research, IMAR-CMA, Dept. of Life Sciences, University of Coimbra, Portugal.
authors.forename: S R Q
authors.initials: SR
authors.lastname: Serra
authors.affiliation: CNR-IRSA Water Research Institute, Brugherio, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Buffagni
authors.affiliation: Department of Plant Biology, University of Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Cambra
authors.affiliation: IRSTEA Bordeaux-Cestas, UR REBX, France.
authors.forename: C
authors.initials: C
authors.lastname: Chauvin
authors.affiliation: IRSTEA Bordeaux-Cestas, UR REBX, France.
authors.forename: F
authors.initials: F
authors.lastname: Delmas
authors.affiliation: Water Development Department, Ministry of Agriculture, Natural Resources and Environment, Cyprus.
authors.forename: G
authors.initials: G
authors.lastname: Dörflinger
authors.affiliation: CNR-IRSA Water Research Institute, Brugherio, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Erba
authors.affiliation: Department of Plant Biology, University of Barcelona, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Flor
authors.affiliation: IRSTEA Lyon, UR MALY, France.
authors.forename: M
authors.initials: M
authors.lastname: Ferréol
authors.affiliation: Department of Biology, Biotechnical Faculty, University of Ljubljana, Slovenia.
authors.forename: M
authors.initials: M
authors.lastname: Germ
authors.affiliation: National Health Institute, Rome, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Mancini
authors.affiliation: Department of Biology, University of Patras, Patras, Greece.
authors.forename: P
authors.initials: P
authors.lastname: Manolaki
authors.affiliation: National Health Institute, Rome, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Marcheggiani
authors.affiliation: ENEA Saluggia Research Center, Saluggia, Italy.
authors.forename: M R
authors.initials: MR
authors.lastname: Minciardi
authors.affiliation: Catalan Water Agency, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Munné
authors.affiliation: Department of Biology, University of Patras, Patras, Greece.
authors.forename: E
authors.initials: E
authors.lastname: Papastergiadou
authors.affiliation: Department of Ecology, University of Barcelona, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Prat
authors.affiliation: National Health Institute, Rome, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Puccinelli
authors.affiliation: IRSTEA Bordeaux-Cestas, UR REBX, France.
authors.forename: J
authors.initials: J
authors.lastname: Rosebery
authors.affiliation: Institute of Aquatic Ecology, University of Girona, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Sabater
authors.affiliation: National Health Institute, Rome, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Ciadamidaro
authors.affiliation: Catalan Institute for Water Research (ICRA), Spain.
authors.forename: E
authors.initials: E
authors.lastname: Tornés
authors.affiliation: Water Development Department, Ministry of Agriculture, Natural Resources and Environment, Cyprus.
authors.forename: I
authors.initials: I
authors.lastname: Tziortzis
authors.affiliation: Institute for Water of the Republic of Slovenia, Slovenia.
authors.forename: G
authors.initials: G
authors.lastname: Urbanič
authors.affiliation: University of Porto, Department of Biology, Portugal.
authors.forename: C
authors.initials: C
authors.lastname: Vieira
mesh_terms: D000383:Agriculture; D000818:Animals; D044822:Biodiversity; D017753:Ecosystem; D004784:Environmental Monitoring; D007448:Invertebrates; D019083:Mediterranean Region; D010839:Phytoplankton; D045483:Rivers / Q000737:chemistry*; D014876:Water Pollution / Q000706:statistics & numerical data*; D060753:Water Quality / Q000592:standards*
keywords: Diatoms; Invertebrates; Least-disturbed conditions; Macrophytes; Mediterranean rivers; Thresholds