title: Response of single benthic metrics and multi-metric methods to anthropogenic pressure gradients, in five distinct European coastal and transitional ecosystems.
abstract: In recent times many benthic indices have been proposed to assess the ecological quality of marine waters worldwide. In this study we compared single metrics and multi-metric methods to assess coastal and transitional benthic status along human pressure gradients in five distinct environments across Europe: Varna bay and lake (Bulgaria), Lesina lagoon (Italy), Mondego estuary (Portugal), Basque coast (Spain) and Oslofjord (Norway). Hence, 13 single metrics (abundance, number of taxa, and several diversity and sensitivity indices) and eight of the most common indices used within the European Water Framework Directive (WFD) for benthic assessment were selected: index of size spectra (ISS), Benthic assessment tool (BAT), Norwegian quality index (NQI), Multivariate AMBI (M-AMBI), Benthic quality index (BQI), (Benthic ecosystem quality index (BEQI), Benthic index based on taxonomic sufficiency (BITS), and infaunal quality index (IQI). Within each system, sampling sites were ordered in an increasing pressure gradient according to a preliminary classification based on professional judgement. The different indices are largely consistent in their response to pressure gradient, except in some particular cases (i.e. BITS, in all cases, or ISS when a low number of individuals is present). Inconsistencies between indicator responses were most pronounced in transitional waters (i.e. IQI, BEQI), highlighting the difficulties of the generic application of indicators to all marine, estuarine and lagoonal environments. However, some of the single (i.e. ecological groups approach, diversity, richness) and multi-metric methods (i.e. BAT, M-AMBI, NQI) were able to detect such gradients both in transitional and coastal environments, being these multi-metric methods more consistent in the detection than single indices. This study highlights the importance of survey design and good reference conditions for some indicators. The agreement observed between different methodologies and their ability to detect quality trends across distinct environments constitutes a promising result for the implementation of the WFD's monitoring plans. Moreover, these results have management implications, regarding the dangers of misclassification, uncertainty in the assessment, use of conflicting indices, and testing and validation of indices.
authors.affiliation: AZTI-Tecnalia, Marine Research Division, Herrera Kaia, Portualdea s/n, 20110 Pasaia, Spain. aborja@azti.es
authors.forename: Angel
authors.initials: A
authors.lastname: Borja
authors.forename: Enrico
authors.initials: E
authors.lastname: Barbone
authors.forename: Alberto
authors.initials: A
authors.lastname: Basset
authors.forename: Gunhild
authors.initials: G
authors.lastname: Borgersen
authors.forename: Marijana
authors.initials: M
authors.lastname: Brkljacic
authors.forename: Michael
authors.initials: M
authors.lastname: Elliott
authors.forename: Joxe Mikel
authors.initials: JM
authors.lastname: Garmendia
authors.forename: João Carlos
authors.initials: JC
authors.lastname: Marques
authors.forename: Krysia
authors.initials: K
authors.lastname: Mazik
authors.forename: Iñigo
authors.initials: I
authors.lastname: Muxika
authors.forename: João
authors.initials: J
authors.lastname: Magalhães Neto
authors.forename: Karl
authors.initials: K
authors.lastname: Norling
authors.forename: J Germán
authors.initials: JG
authors.lastname: Rodríguez
authors.forename: Ilaria
authors.initials: I
authors.lastname: Rosati
authors.forename: Brage
authors.initials: B
authors.lastname: Rygg
authors.forename: Heliana
authors.initials: H
authors.lastname: Teixeira
authors.forename: Antoaneta
authors.initials: A
authors.lastname: Trayanova
mesh_terms: D044822:Biodiversity; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D005060:Europe; D009792:Oceans and Seas; D012623:Seawater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000592:standards; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data*
chemical_list: D014874:Water Pollutants, Chemical