Assessment of the ecological status of north‐eastern Adriatic coastal waters (Istria, Croatia) using macroalgal assemblages for the European Union Water Framework Directive

Abstract

ABSTRACT1. Based on the inclusion of macroalgae in the European Union Water Framework Directive as quality elements for the evaluation of the ecological status of coastal waters, the suitability of one (Ecological Evaluation Index, EEI) of several previously proposed evaluation methods in the particular ecological conditions of the northern Adriatic Sea was tested.2. The EEI was assessed for 10 locations (polluted and putatively pristine) scattered along 60 km of the western Istrian coast. The sampling was performed seasonally at 1 and 3 m depth by destructive (determination of species cover and biomass) and non-destructive (determination of species coverage using digital photography) methods.3. When assessed at 1 m depth the spatial scale weighted EEI for the west Istrian coast was 8.1, corresponding to an ecological status class (ESC) value of high. However, data for 3 m depth gave a spatial EEI of 6.72 which corresponds to an ESC value of good. Regressions of the ratio of ecological state group I (ESG I, i.e. thick leathery, calcareous and crustose species) over total algal abundance with the pollution gradient (obtained using principal components analysis (PCA) ordination of environmental variables) were significant at 3 m but not at 1 m depth. This was due to the high abundance of ESG I macroalgae Corallina elongata and Cystoseira compressa at 1 m depth at polluted stations. Similar regressions were obtained using cover, biomass and coverage.4. It is concluded that the EEI method may be suitable for the classification of coastal waters in the northern Adriatic only in certain cases. A better assessment of ecological status using this method would require more realistic estimations based on the inclusion of data from several sampling depths. As all three abundance measures (cover, biomass, coverage) gave similar results, coverage (using digital photography) is suggested as being a preferred measure owing to the rapidity of sampling at several depths and less time-consuming laboratory work.

Ecological Evaluation Index continuous formula (EEI-c) application: a step forward for functional groups, the formula and reference condition values

“…They may take advantage over macroalgae in oligotrophic conditions by using nutrients from the sediment and they may sustain growth in degraded conditions until light, due to epiphyte load, or high water turbidity become limiting (HEMMINGA & DUARTE, 2000). On moderately impacted coasts, slowgrowing, shade-adapted calcareous species (ESG IC) often dominate (PANAYOTIDIS et al, 2004;ORFANIDIS & PANAYOTIDIS, 2005;ARÉVALO et al, 2007;IVE A et al, 2009). Of these species, the Corallina spp.…”

“…On the other hand, difficulties applying the EEI in specific coastal water sites in Spain (ARÉVALO et al, 2007), Croatia (IVE A et al, 2009) and Malta (AZZOPARDI & SCHEMBRI, 2009) were observed and discussed (ORFANIDIS, 2007;BALESTEROS et al, 2007a). Beside difficulties that may have been due to low data compatibility, the EEI was criticized for three reasons: (1) species of the same ESG may respond differently to similar stressors, such as species of the genera Cystoseira and Corallina, (2) the functional group approach used originally proposed to predict productivity and other ecological attributes (e.g.…”

The overlooked role of biotic factors in controlling the ecological performance of artificial marine habitats

“…S1). The natural sites (Faborso, Kamenolom and Stari Grad) were characterized by gently sloping, rocky bottoms densely forested by Cystoseira (Iveša, Lyons & Devescovi ). The three artificial sites (Valalta, Bolnica and Marina) were interspersed with natural sites, and generally located very close to them.…”

Indices to monitor coastal ecological quality of rocky shores based on seaweed communities: simplification for wide geographical use

“…Using specific ecological classifications of seaweed species in different geographical areas or different impact sources can lead to an unmanageable tool use, and it does not allow any comparison of results between different areas or impacts. The classification proposed by Orfanidis et al (2001) has proven effective for the purpose it has been created for and has been applied in several regions (Panayotidis et al, 2004;Orlando-Bonaca et al, 2008;Ivesa et al, 2009;Orlando-Bonaca & Lipej, 2009). Therefore, it seems more sensible to focus scientific attention on the assignment of seaweed species to each of the two functional groups that best reflect their sensitivity to environmental disturbance, rather than having each research team using alternative approaches.…”