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A model-based fish bioassessment index for Eastern Mediterranean rivers: Application in a biogeographically diverse area
Abstract
In ecosystems with high fish species endemicity, such as Mediterranean-type rivers, biogeographical differences among ecoregions present serious obstacles to developing broadly-applicable river bioassessment indices. This impediment has contributed to a serious time-lag in developing EU policy-relevant fish-based indices in the Eastern Mediterranean countries. Here we present the first model-based fish index for the Eastern Mediterranean (the Hellenic Fish Index, HeFI) in an effort to overcome biogeographic differences among the area's biotically heterogeneous rivers. The index is based on modelled reference conditions and employs site-specific electrofished fish samples from an extensive dataset from Greece that covers six freshwater ecoregions, including five transboundary river basins flowing through six countries. Environmental and anthropogenic pressure data were procured from 403 sampled river sites and ecologically-relevant traits were defined for 103 collected fish species. For the development of the index, we first diagnosed least degraded sites forming a calibrated reference site dataset and secondly quantified differences of fish metrics between the reference and impaired sites. Four trait-based fish metrics showed the best ability to discriminate between impaired and reference sites. The index performed well in discriminating anthropogenic pressure classes, giving a significant negative linear response to a gradient of anthropogenic degradation. HeFI successfully assessed both small and large rivers in different freshwater ecoregions. This geographically broad-scale index development shows that key trait-based reference conditions can be produced by a predictive model in remarkably heterogeneous rivers where range-restricted fishes dominate. This index promotes a screening-level bioassessment application that may be further developed and refined with relevant monitoring.
... In Greece, dams and/or barriers have been identified as evidence-based anthropogenic pressures rather recently, particularly with concern for in-stream biota Skoulikidis et al., 2009 ;Zogaris et al., 2018 ), hydrology and hydromorphology ( Ioannou et al., 2009 ); coastal processes ( Sylaios and Kamidis, 2017 ;Sylaios et al., 2012Sylaios et al., , 2010 and riparian zones ( Zaimes and Iakovoglou, 2021 ). It is widely recognized in Greece that for several fish species there are serious problems with movements and migration due to barriers ( Barbieri et al., 2015 ;Bobori et al., 2001 ;Cheimonopoulou et al., 2011 ;Kokkinakis, 2007 ;Leonardos, 2015 ;Sapounidis et al., 2019 ). ...
... RHS applications, using 500 m long river survey segments may not adequately assess connectivity decline over the wider basin. In contrast, records of barriers, especially those downstream of fish sampling sites, are prevalent in nation-wide fish-based assessments; with reference to barrier impacts at river segment and basin scales ( Zogaris et al., 2018 ). In our opinion, ichthyological surveys may be more sensitive in recording longitudinal barriers since they presumably impact fish communities; however, many small barriers may be under-reported and perhaps under-appreciated in other monitoring protocols. ...
... In Greece, restoration action for rivers and running waters in general has lagged behind other EU states . Modern methods for assessing hydromorphological degradation and prescribing specific ecological restoration have only begun recently ( Dimitriou and Stavroulaki, 2018 ;Mentzafou et al., 2016 ;Ourloglou et al., 2020 ;Zogaris et al., 2018 ). Recommendations or plans for dismantling in-stream infrastructure for fish movements are still scarce; very few studies have promoted specific barrier removal guidelines or proposals ( Dimitriou et al., 2015 ). ...
An inventory of anthropogenic barriers to longitudinal river connectivity in Greece is presented based on an extensive literature review. We mapped Greece's 275 major dams and developed an ongoing inventory of 661 other barriers compiled from various sources; we further summarized future dam barriers as published in Greece's river basin area management plans. Environmental professionals and engineers were also interviewed to investigate perceptions and preferences concerning longitudinal river connectivity. Fish were given priority as reference organisms in questionnaire responses, the reviewed literature and relevant legislation, but other biodiversity elements were rarely addressed. Dams prevail as the most prominent perceived barrier pressures while most respondents seem to recognize problems with other barrier types as well. However, mention of small barrier infrastructure in the literature or legislation is very scarce and there is no systematic inventory of in-stream infrastructure barriers, fish passes or other barrier mitigation or restoration interventions. Recommendations for particular unmet needs and opportunities for restoration of a variety of barrier types are addressed. It is crucial that attention for preservation and restoration measures involving lotic waters connectivity issues be introduced in the country's EU-inspired water body management and within protected areas in particular.
... Trained and experienced electrofishing operators, usually the same personnel participating for many consecutive years, identify fishes to species level before releasing them and may keep questionable specimens for further lab identification. The standard field protocol procedure is provided in IMBRIW (2013) and is described in Zogaris, et al. (2018). ...
... Sperchios and Squalius sp. Evia (Barbieri, et al., 2015;Geiger, et al., 2014;Kottelat & Freyhof, 2007;Zogaris, et al., 2018). In the present study we include these distinctive range-restricted taxa in our analyses. ...
... Few studies evaluating species coverage from N2K are based on abundance survey data, since such data, over a broad spatial extent, are scarce (Zisenis, 2017) and may impose high uncertainty (Pressey, 2004). The use of electrofishing sampling data does have some limitations but within data-scarce conditions, it seems to be an adequate wide-ranging assessment method providing standard quantitative samples in most types of running waters (Economou et al., 2016;Zogaris et al., 2018). The HD aims for the Annex listed species to reach favorable conservation status; therefore, abundance data derived from field surveys should be utilized with care and caution. ...
Europe’s Natura 2000 network, based on the EU Birds and Habitat Directives, has rapidly expanded protected areas targeting species and habitat types. In Greece, 52.4% of native freshwater fish are considered as species of EU community interest within the Habitats Directive (HD). However 31.3% of all threatened fish species at a global level and 32.0% at national level, are not included in the Habitat Directives Annex lists. Fishes in Greece’s rivers are understudied, precise knowledge of their distributions is poor for most species. We utilize a large set of site-based electrofishing samples to explore the coverage of these species by the country’s Natura 2000 sites. Field surveys recorded 102 species inhabiting rivers within 645 sampling sites. Although the majority of HD listed, threatened and endemic range-restricted freshwater fish species exist within the current N2K network, important gaps are evident and four HD species were not found within any Natura 2000 sites. In analyzing fish densities from field sampling, only two upland-stream species, Salmo farioides and Barbus strumicae, show significantly higher abundance inside N2K sites. Applying a Combined Index utilizing IUCN vulnerability status, species rarity and richness, we identified 161 hotspot sites for riverine fishes; 50.9 % of all hotspots are located outside of N2K network, especially in lowland areas. Unprotected hotspot areas, with a high concentration of hotspots are mapped; the river basins with the highest number of such unprotected hotspots belong to the Strymonas, Pinios, Evrotas and Aoos rivers. With concern for the EU’s revised biodiversity conservation strategy, our screening level assessment provides insights for unmet conservation needs and the method is readily transferable to other states and protected area jurisdictions.
... The objective of this study is to provide insights on human pressures applied in Greek rivers, along with their response towards fish assemblages, as depicted by a widely used fish-bioassessment index in Greece, the Hellenic Fish Index (HeFI) (see Zogaris et al., 2018 ). In more detail, we aim: a) to identify dominating anthropogenic pressures, b) to delineate pressure spatial patterns at the national scale, c) to analyze pressure response towards the component metrics of HeFI, and finally d) to evaluate sensitivity and specificity between various pressure groupings and the ecological status ( Van de Bund & Solimini, 2007 ) assessed by the HeFI index. ...
... Fish assemblage data consisted of species abundance data for 111 fish species, assigned to length classes of 5 cm. Utilizing fish species trait characterizations (presented in Zogaris et al., 2018 ), data tables were transformed accordingly to assess HeFI's four component trait metrics: (1) relative abundance of insectivorous species larger than 100 mm (INSV), (2) relative abundance of omnivorous species smaller than 100 mm (OMNI), (3) relative abundance of benthivore smaller than 150mm (BENTH) and (4) relative abundance of potamodromous species (POTAD). Descriptive statistics for fish sampling data and HeFI's four component trait metrics are presented in Annex (Appendix Table A2 ). ...
... In a second step, the HeFI model was employed to extract ecological quality ratio values (EQR) and subsequently the ecological status ( Van de Bund & Solimini, 2007 ) for the fish biological quality element (BQE). All samples that did not meet the criteria set for the construction of the HeFI (sampling length ≥50m, sampling area ≥100m 2 ; see Zogaris et al., 2018 ), were excluded from the analysis. Additionally, an expert judgment filter was also applied, excluding all samples with absolute abundance below 15 specimens from further analysis, considering limitations of the model for poor abundance sites. ...
Surveys of anthropogenic pressures and their effect on river fish communities have rarely been conducted in the eastern Mediterranean countries, in contrast to the rest of Europe. An electrofishing dataset of 1586 samples (818 sites) was analyzed to investigate human-induced pressures on river fish assemblages in Greece. Pressure patterns and pressure-impact analysis towards the national fish bioassessment index (HeFI) and its four-constituent metrics are depicted. At each sampling site 11 anthropogenic pressure variables were assessed, and several integrated/grouped pressure indices were computed, including hydrology, morphology, connectivity, and water quality. Almost 60% of samples were classified as impacted. The most common pressure groups affecting Greek rivers were hydrology recorded at 714 (45%) samples, morphology at 692 (44%) and artificial barriers at 382 (24%) samples. The same pattern persists among the six investigated freshwater ecoregions in Greece. The most impacted ecoregions were Thrace (76% impacted samples), Western Aegean (67% impacted samples) and Macedonia-Thessaly (67% impacted samples). Lowlands and large rivers displayed higher levels of degradation, but water pollution was not recognized as a key stressor in most running waters. Pressure-impact analysis demonstrates that all HeFI component metrics (insectivorous, omnivorous, benthivores, potamodromous species) respond as expected to almost all integrated pressure indices considered, as regards: a) the direction of response, and b) the response to pressure intensity gradients. However, the longitudinal connectivity stressor clearly fails to respond towards metrics. The findings confirm the usefulness of model-based indices, using fish assemblage functional metrics as bioassessment tools. Specific recommendations for refining the tools are provided.
... Each ecoregion hosts distinctive assemblages of freshwater fish species and other aquatic/semi aquatic life forms, many being endemic to each region (Zogaris and Economou, 2017). The spatial scale of the ecoregion is widely used as standard geographical and non-political framework for conservation/ecological evaluations (Abell et al., 2008) and biological assessments (Zogaris et al., 2018). ...
... depth) and flow conditions (from small fast flowing upland streams to main-stem rivers close to river mouths). The procedure is standardized basically following CEN (2003) guidelines for electrofishing and sampling targeted river bioassessment during most samples (Zogaris et al., 2018); for method description see Economou et al. (2016). ...
... EU WFD monitoring). The increasing invasion of lotic waters by NIFS shows an expanding trend through site-based monitoring during this period (Economou et al., 1999;Koutsikos et al., 2012;Zogaris et al., 2018). ...
Mediterranean lotic waters such as rivers, streams and springs are poorly monitored for non-indigenous fish species (NIFS). Since these systems are stressed by multiple anthropogenic pressures, it is important to build robust procedures to track NIFS distribution and spread. This study applies a multi-faceted assessment of NIFS in the lotic ecosystems of Greece at different spatial scales by providing: a) a historical review of temporal patterns and arrival pathways of fish introductions in river basins of Greece (140 basins) across 100 years; b) an analysis of occurrence and abundance data of NIFS assemblages at the lotic site scale (644 electrofished sites); c) the mapping of NIFS distributional patterns at river basin (75 basins) and regional scales (7 freshwater ecoregions); and, d) a vector analysis of fish translocations using an ecoregional framework. In total, 55 NIFS were recorded (25 alien and 30 translocated); however, there is a low incidence of NIFS in lotic waters at the site scale (30 NIFS recorded in the field samples; 10 alien and 20 translocated). NIFS introductions in Greece appear to be influenced by specific socio-historical periods, indicating a gradual increase since late 1970s. Despite this increase, our study provides evidence that only four alien species are currently widespread and common in the rivers and streams of Greece: Gambusia holbrooki, Carassius gibelio, Pseudorasbora parva, and Lepomis gibbosus (in order of recorded abundance). NIFS tend to be absent or distributed in very low numbers in upland streams and in smaller river basins. However, the issue of translocated fish species is shown to be a sorely neglected problem that is difficult to track. This review tests a readily transferable screening procedure, contributes to the application of the European Union Regulation on Invasive Alien Species; it suggests gaps and uncertainties, and proposes conservation and management actions.
... Each ecoregion hosts distinctive assemblages of freshwater fish species and other aquatic/semi aquatic life forms, many being endemic to each region ( Zogaris and Economou, 2017). The spatial scale of the ecoregion is widely used as standard geograph- ical and non-political framework for conservation/ecological evalua- tions ( Abell et al., 2008) and biological assessments ( Zogaris et al., 2018). ...
... depth) and flow conditions (from small fast flowing upland streams to main-stem rivers close to river mouths). The procedure is standardized basically following CEN (2003) guidelines for electrofishing and sam- pling targeted river bioassessment during most samples ( Zogaris et al., 2018); for method description see Economou et al. (2016). ...
... EU WFD monitoring). The in- creasing invasion of lotic waters by NIFS shows an expanding trend through site-based monitoring during this period ( Economou et al., 1999;Koutsikos et al., 2012;Zogaris et al., 2018). ...
1. Rainbow trout is ranked as one of the world's worst alien invasive species; in Europe however the extent of established populations remains localized and poorly reported. This study aims to assess rainbow trout establishment in Greece and explores the factors of establishment success or failure.
2. We analyzed fish samples and site specific environmental attributes collected during the past 18 years (2001-2017). We reviewed all available literature on rainbow trout distributional patterns in parallel to those of the Greek native Salmo trout species and applied demographic criteria to infer potential establishment.
3. Poor persistence of populations and population structure data support the argument that recruitment of rainbow trout is extremely limited in Greece. Lack of suitable environmental conditions is not the main factor of rainbow trout’s establishment failure. Genetic factors affecting the reproductive process, possibly through a combination of outbreeding depression resulting from the admixture of unrelated intraspecific lineages and maladaptive behaviours resulting from domestication selection acting in captivity, remain probable causes of poor establishment for the Greek populations of rainbow trout.
4. Overall, the threat of rainbow trout as a highly invasive species in Greece is lower than suggested by recent risk assessments.
... Visual assessment of habitat parameters (per IMBRIW 2013). Visual assessment of conditions and ecological integrity as best as possible using basic anthropogenic pressure parameters (as per Zogaris et al. 2018). Photography and videography of habitat conditions. ...
... Laboratory re-examination of nearly all collected specimens (excluding the larger fishes that were returned alive to the river / or kept in Kosovo). Confirmation of pre-assessment of the environmental degradation of each site using remote sensed references (as per Zogaris et al. 2018). Google Earth images where used to assess anthropogenic pressures and presumed impacts on the fish species, populations and fish assemblage. ...
... The problem of increased sedimentation and siltation could be a negative impact for some species in other parts of the dowstream river valley as well. Siltation is known to affect many species of fishes (Wood & Armitage 1997) and is an important parameter altering fish community conditions especially affecting benthic fishes, and indicators of in-stream ecological integrity (Zogaris et al. 2018). Increased turbidity may also create certain problems especially for fishes feeding using sight (e.g. ...
Field, laboratory and desk-study research relating to Environmental Baseline Surveys on fishes and fish habitat for the “Feasibility Study, Preliminary Design and Tender Documents for Road N9 Pristinë – Pejë, Section from Kijevë/Klina to Zahaq”. This research provides a review of the ichthyological interest in the particular river segment and presents the results of a two day field survey. The field survey employed the use of back-pack electrofishing in order to sample representative habitats within the river. Work developed in cooperation with Dept. Biology, University of Pristina.
... A remarkable number of upland rivers still show hydromorphologically good conditions. Ecological status monitoring and assessment studies in Greece confirm that river basins, such as the Acheloos and Arachthos as well as headwaters and tributaries of the Nestos, Axios, Aliakmon, Aoos, Acheloos, Pinios, and Alfeios, satisfy EU criteria regarding hydrogemorphological, chemical, and biological reference conditions (Economou et al. 2016;Lazaridou et al. 2018a,b;Zogaris et al. 2018b). ...
... Greece has adopted EU water policies and rules including the WFD (Kanakoudis and Tsitsifli 2015). In the frame of the national monitoring program that is being implemented in two phases (2012e2015, 201823), national assessment classification systems have been developed (Skoulikidis et al. 2006;Lazaridou et al. 2018a,b;Zogaris et al. 2018b) and are being applied. The 1st River Basin Management Plans (RBMPs) have been elaborated (200915) and have been revised in 2017, and the 2nd round is ongoing (201621). ...
This chapter examines fifteen major river basins, six being transboundary, that encompass the biogeographical mosaic of the Balkan Peninsula and deliver over 80% of river flows into the Eastern Mediterranean Sea. Apart from a number of mountain river sections with spectacular wilderness landscapes still remaining intact, the majority of the Balkan rivers is under multiple human-induced pressures and increasingly threatened as a result of socioeconomic drivers combined with poor environmental planning and inadequate environmental legislation or enforcement. Lowland river sections face substantial hydro-morphological modifications and are at the greatest pollution risk as a result of insufficient treatment of municipal, mining and industrial wastewaters. New threats include many new dams, water transfers and hundreds of small hydro-electric projects. River flows and wetlands are declining at an alarming rate;; water quality deterioration is locally severe, while fragmentation of terrestrial and aquatic habitats even in protected areas cause irreversible disturbance to the connectivity, biodiversity and ecological quality of Balkan rivers despite recent integrated policy efforts such as the EU′s Water Framework Directive.
... Biological quality indices for each BQE for the assessment of the ecological status included: The HESY2 (Hellenic Evaluation System 2) for benthic macroinvertebrates [32,33], the IPS (Specific Pollution Sensitivity) diatom index harmonized for Greece [34], the IBMR index for macrophytes adjusted for Greece [35], and the Hellenic Fish Index (HeFI) for fish fauna [36]. The C-P quality has been carried out using classification systems for nutrients and dissolved oxygen (DO) [37]. ...
... Contrary to the initial RBMPs, in their first update, WBs have been assigned to ecological classes using appropriate assessment and classification systems of hydromorphological, C-P, and BQEs. These systems were largely developed by the members of the NCW; a nutrient classification system [37] and metrics for the classification of BQ using macroinvertebrates [32,33], phytobenthos [34], and fish [36]. In the future, classification systems for intermittent rivers and streams should be developed and applied. ...
Based on historical and WFD-compliant data, the recent inter-annual ecological status and the long-term chemical-physicochemical quality trends of eighteen characteristic Greek rivers have been assessed and interpreted in view of implementing EU environmental policies and the evolution of human pressures. Considering predominating poor ecological status in most of the river outflows, the strengths and weaknesses of the WFD implementation have been highlighted. The long-term decrease of ammonium and nitrite concentrations along with relatively low recent BOD5 levels, indicate a general improvement of WWTP infrastructure in Greece and the other riparian countries, whereas the improvement of nitrate quality is attributed to the reduction of fertilizers use, and possibly, to the successful application of the Nitrates Directive in certain basins. Despite capacity building in governance and administrative infrastructure the recent years, River Basin Management Plans (RBMPs) are being implemented centrally, largely mechanistically, with minor public participation. Regarding WFD implementation weaknesses and gaps, concrete proposals have been formulated considering both policy/administrative and technical issues. To efficiently conserve and restore aquatic ecosystems, the forthcoming RBMPs should be consistent with ecosystem services principles focusing on nature-based solutions, along with changing attitudes of the state authorities and the public.
... Sampling consisted primarily of electrofishing, following approaches used through the European Union Water Framework Directive (EU WFD) monitoring protocols (CEN, 2003) which has been applied in several areas of the Balkans (IMBRIW, 2013;Zogaris et al., 2018). Sampling was located at a river stretch usually demarcated by physical boundary features to minimize fish escape during electrofishing (e.g. ...
... Anthropogenic degradation of the sampled river sites was assessed based on the identification of anthropogenic pressures known to influence and impact fish (see Degerman et al., 2007;Schinegger et al., 2012, for criteria and relevant references). In order to provide a rapid assessment of the level of anthropogenic impact (degradation) of each site we chose selected pressures for which we could rapidly gather on-site knowledge as has been done in other Balkan countries (Zogaris et al., 2018). Twelve anthropogenic pressure categories were assessed based on our on-site observations (recorded in the sampling field protocol), published pressure assessments (i.e. ...
Fish assemblages and their distributions in the western Balkan rivers have rarely been investigated. This study provides initial insights into the spatial patterns of fish distributions in the main-stem of the White Drin in Kosovo. Sampling primarily utilized back-pack electrofishing at 11 sites along the river's entire main stem, recording 21 species. Identification of most fish species was confirmed through DNA barcode analyses; two yet unnamed species are present and some taxonomic problems were discovered. The abundance of non-native species was low (5.9% of the catch) but seven of the eight non-natives have established populations. A longitudinal fish zonation pattern was described for the first time in this river; fish assemblages in an upstream-to-downstream gradient were characterized by a decrease of cold-water species (salmonids, minnows) and an increase of large-river cyprinids and non-native species. Multivariate ordination and network analyses demarcate preliminary fish assemblage types and specific environmental and anthropogenic pressure attributes are shown to influence assemblage structure. Natural assemblage patterns may be locally disrupted by anthropogenic pressures such as pollution and hydromorphological disturbances, however most sites show semi-natural features and conditions. Recommendations for conservation and further research are provided.
... The estimation of the quality status of surface water samples from the site-based river ichthyofauna samples was accomplished using the HEFI (Hellenic Fish Index). This index has been developed based on modeled reference conditions and employs site-specific electrofished fish samples from an extensive dataset from Greece (Zogaris et al. 2018). The estimation of the quality status of samples based on benthic macroinvertebrate communities was assessed using the HESY2 (Hellenic Evaluation System 2). ...
The quantitative and qualitative status of a riverine ecosystem is mainly controlled by the characteristics of the catchment (topography, land use, and geological structure) and climatic factors (precipitation and temperature), both of which can be affected by anthropogenic activities. To quantify the impact of humanly imposed pressures on river discharge and to determine the dominant stressors that affect the hydrological regime of Greek rivers, two discharge datasets consisting of discharge/ichthyofauna and discharge/benthic macroinvertebrate measurements were employed, and 36 predictor variables were statistically elaborated. Impacted samplings were defined based on the classification of the corresponding biotic indices sensitive to hydrological alterations. The assessment indicated that the median discharge of impacted rivers was lower in relation to unimpacted conditions in all river types by up to 85% (R-M3), except for the case of R-M5 (temporary rivers), where discharge was higher by up to 46%. The most important variables affecting discharge values were the proximity of the dam upstream of the sampling site, the distance to source, the catchment area upstream, the presence of siliciclastic rocks upstream, annual precipitation, and the presence of artificial surfaces. Surprisingly, irrigated land area and water abstractions volume were not indicated as major driving variables affecting the hydrology of Greek rivers, possibly due to limitations of the current methodological approach. The development of a hydrological regime alteration index, specifically for Greek rivers, based on the deviation of the current state from the unimpacted conditions can be a valuable tool for the implementation of Water Framework Directive 2000/60 objectives concerning the hydromorphological quality of riverine ecosystems.
... However, the responses of candidate metrics to human impacts were weak and highly variable in IRES due to low local species richness and the prevalence of endemic species, which prevented metric selection. Instead, each country within the Mediterranean ecoregion developed indices effective at either a national scale (Zogaris et al., 2018) or designed specifically for one or few river basins (e.g. Magalhães et al., 2008;Aparicio et al., 2011;Hermoso et al., 2010). ...
... Zogaris, S., Tachos, V., Economou, A.N., Chatzinikolaou, Y., Koutsikos, N., Schmutz, S., 2018. A model-based fish bioassessment index for Eastern Mediterranean rivers: application in a biogeographically diverse area. ...
Kαθορισμός μέτρων αποκατάστασης της ποτάμιας συνεκτικότητας και της ανόρθωσης ενδιαιτημάτων του ενδημικού είδους «αττικόψαρο» (Pelasgus marathonicus) και άλλων ειδών πανίδας [Πρώτη Ενδιάμεση Έκθεση]
... Fish sampling data in lotic waters were acquired from research surveys conducted between the years 2001-2017 by the Hellenic Centre for Marine Research (HCMR); these cover the entire mainland as well as the major islands of Greece. Most of the sampled data have been recently published [14,19]. Field samplings were conducted primarily through a standardized electrofishing procedure following the FAME research project guidelines [20] with some modifications; for a detailed description of the sampling procedure see [21]; in some cases seine nets and other methods were also used to ascertain fish presence. ...
Non-indigenous fish species (NIFS) can cause severe ecological impacts on the invaded ecosystems and are considered as one of the leading factors of freshwater biodiversity loss. Unraveling the spatial overlap between NIFS and critically endangered (CR) fish species can contribute to targeted conservation actions to minimize the potential negative effects. In this study, we applied geostatistical analyses to investigate the spatial overlap of NIFS against fish species that are designated under the CR status according to the IUCN and the Hellenic Zoological Society (HZS) Red Lists. Distributional data (presence–absence) from 800 records of 52 NIFS were compiled for both lentic and lotic ecosystems of Greece. Our results indicate that freshwater ecosystems under high NIFS richness were located mainly in lowland areas and often near large cities and ecosystems with well-developed commercial and recreational fisheries. On the contrary, low NIFS richness was observed in mountainous regions and in relatively small river basins. Overlapping areas of CR species with moderate to high NIFS richness (1.5–4.3 NIFS per 1 km2) were relatively high (~50%). A quarter of the overlapping areas (24.8%) fall within NATURA 2000 network, where legal management bodies could implement specialized programs to minimize the negative impacts. However, the majority of CR fish species’ distribution remains in unprotected areas indicating that protected areas should be re-designed to include areas containing freshwater species under the highest threatened category. Our findings demonstrate that whole assemblages of fishes are rapidly changing as NIFS spread into Greece and many freshwater ecosystems of outstanding biodiversity conservation value are under significant invasion pressure.
... • Alien species are often omitted or combined with native fish fauna in river monitoring assessments within the context of the Water Framework Directive (WFD) (Ruaro et al., 2021). Since rather few alien species are recorded in most routine surveys in Greek rivers, these are usually lumped within the whole fish assemblage as in other EU countries (Zogaris et al., 2018). A revision of metrics in current bioassessment indices should be attempted to include aliens as indicators of ecosystem degradation. ...
Many studies around the globe have documented that the introduction of non-indigenous fish species (NIFS) may pose severe impacts on native biota, ecosystem functioning and ecosystem services. In Greece, publications on NIFS have increased in recent decades, however review studies of past and current scientific research on freshwater NIFS in the country are currently lacking. Τhe aim of the present study was to: (a) assess the current state of knowledge of freshwater NIFS in Greece based on the existing scientific literature, (b) evaluate well-studied areas of NIFS research, and (c) identify important gaps that may direct national authorities to implement appropriate research, management and conservation actions reversing the negative impacts of NIFS. A systematic literature review on NIFS research within Greek inland waters was performed by applying the PRISMA methodology (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). Overall, our initial search resulted in 2,794 published articles, 87 of which met our selection criteria and were thus included for full analysis. Evidently, NIFS failed to attract the interest of ecologists in Greece until the turn of the century, at which point, publications increased at a rapid rate. However, the majority of the studies were mainly monothematic concerning NIFS distribution within freshwater ecosystems of Greece (37%), followed by studies on ecological and biological aspects of NIFS (28%). Studies based on fieldwork and laboratory experiments were by far the most common type of research, followed by studies based on bibliographic data. Despite the fact that almost half of the publications were field observational studies, most of them used only qualitative data (plain presence/absence data). Critical aspects of impact assessment were missing; 84% of the reviewed studies did not provide any concrete evidence of NIFS impacts to native biota. Overall, the focus of the studies was uneven, with important gaps in areas of theoretical and practical importance for policy-relevant detection, control and management of NIFS. Findings may assist researchers in filling scientific gaps identified by our review and guide authorities to define national priorities to prevent and control the spread of NIFS within the country.
... Fish sampling data in lotic waters were obtained from various research surveys conducted between the years 2001-2017 by the Hellenic Centre for Marine Research (HCMR); these cover the entire mainland as well as the major islands of Greece. Most of the sampled data are publicly available and have been recently published in a number of studies [4,6]. Field sampling was conducted primarily through a standardized electrofishing procedure following the FAME research project guidelines with some modifications; for a detailed description of the sampling procedure see Economou et al. [7]; in some cases seine nets and other methods were also used to ascertain fish presence. ...
The introduction of non-indigenous fish species (NIFS) to freshwater ecosystems is considered as one of the leading factors associated with freshwater biodiversity loss. Unravelling the spatial overlap between NIFS and critically endangered (CR) fish species can contribute to targeted conservation planning and actions to minimize the potential negative effects. In this study, we applied geostatistical analyses of species distribution data to investigate the potential overlapping areas of NIFS against fish species that are designated under CR status according to the International Union for the Conservation of Nature (IUCN) and the Hellenic Zoological Society (HZS) Red Lists. Distributional (presence–absence) data of all NIFS were compiled for both lentic and lotic ecosys-tems of Greece. In total, 800 records were utilized from 169 lakes (based on literature review) and 631 river sites from 51 river basins (based on sampling data). Our results indicate that freshwater ecosystems under high NIFS richness are located mainly in lowland areas of western, central and northern Greece usually near large cities and ecosystems with well developed commercial and recreational fisheries. On the contrary, low NIFS richness was observed in mountainous regions and small river basins. Overlapping areas of CR species with moderate to high NIFS richness (1.5–4.3 NIFS per 1 km2) were relatively high (~50%). Many of the overlapping areas fall within NATURA 2000 network, where legal management bodies can implement management programs to minimize the negative impacts. However, some areas of conflict are in unprotected regions and may be likely to experience significant negative biodiversity impacts. The use of the CR status is useful as a proxy indicator for some of Greece’s most important inland water ecosystems in order to avoid new invasions and to manage established alien and translocated species. Our findings demonstrate that many freshwater ecosystems of outstanding biodiversity conservation value in Greece are under significant invasion pressure.
... nobiliana (Zogaris et al, 2018;Tiralongo et al, 2019). These torpedoes may be considered juveniles and adults. ...
Forty-four specimen of common Torpedo (Torpedo torpedo) were collected from discarded catch of long-line boat’s haul from Sidi Sha’ab harbor, Tripoli, in May 2016 and used for establishing morphometric traits of the fish. The specimens ranged in size from 13.3 to 68.2 cm and in total weight from 92.61 to 989.25 gm. The results revealed that the value of the constant b of the length-weight relationship was 1.9064 indicating negative allometric growth (b< 3). The condition factors Kf and Kc decreased progressively from 2.54 and 1.82 in the smallest fish size group (17.2cm) to the largest one (67.5cm.) which recorded a rare values of (Kf= 0.32 and Kc= 0.25), respectively. The length frequency distribution indicated that the youngest size-group (17.2cm) peaked to a quarter of the studied samples. Morphometric traits of the torpedo were related to total length as percentage ratios. Disk length and diameter were larger in female (48.6 and 43.0%) than in male (47.4 and 41.2%).
... However, the responses of candidate metrics to human impacts were weak and highly variable in IRES due to low local species richness and the prevalence of endemic species, which prevented metric selection. Instead, each country within the Mediterranean ecoregion developed indices effective at either a national scale (Zogaris et al., 2018) or designed specifically for one or few river basins (e.g. Magalhães et al., 2008;Aparicio et al., 2011;Hermoso et al., 2010). ...
In a nutshell:
▪ There is a variety of benefits that IRES provide to our societies, from the provision of materials such as water and timber, to iconic species, the regulation of biogeochemical cycles, and space for cultural manifestation and as a corridor for both wild and herded animals.
▪ Drying and rewetting processes, timing and duration of different aquatic phases, have an effect on the biodiversity and ecosystem functioning, as well as on the provision of ecosystem services and on the social perception of them.
▪ There are intrinsic and relational values associated to IRES that are not usually recognised, including sense of place, cultural identity, social cohesion or nature stewardship.
▪ There is a long list of indicators that can be used to assess the provision of ecosystem services, and different techniques of monetary and non-monetary methods can be applied to assess their value.
▪ Public participation is also necessary to understand the multiple values of IRES and to improve social perception. Participatory mapping, citizen science, and scenario planning are some of the methodologies can be employed.
... However, the responses of candidate metrics to human impacts were weak and highly variable in IRES due to low local species richness and the prevalence of endemic species, which prevented metric selection. Instead, each country within the Mediterranean ecoregion developed indices effective at either a national scale (Zogaris et al., 2018) or designed specifically for one or few river basins (e.g. Magalhães et al., 2008;Aparicio et al., 2011;Hermoso et al., 2010). ...
... However, the responses of candidate metrics to human impacts were weak and highly variable in IRES due to low local species richness and the prevalence of endemic species, which prevented metric selection. Instead, each country within the Mediterranean ecoregion developed indices effective at either a national scale (Zogaris et al., 2018) or designed specifically for one or few river basins (e.g. Magalhães et al., 2008;Aparicio et al., 2011;Hermoso et al., 2010). ...
... It is alarming that Pelasgus populations were not found in our and other recent surveys in several river basins that lie within their distribution ranges (e.g. Economou et al., 2016;Zogaris et al., 2018). The presence of private cyt b haplotypes in populations of both species points to the uniqueness and vulnerability of each population. ...
Pelasgus Kottelat & Freyhof 2007 (Leuciscidae) is a freshwater fish genus endemic to the Southern Balkans. The distribution of most of its species is insufficiently known. Pelasgus was molecularly studied only marginally, and the genetic diversity of individual species or populations, crucial for their conservation, is completely unknown. We studied distribution and genetic diversity of Pelasgus stymphalicus (Valenciennes 1844) and Pelasgus marathonicus (Vinciguerra 1921), two widespread species from southern Greece. Our data, based on cytochrome b sequences, confirmed that a number of populations whose taxonomic status had been uncertain, belong to one of these species. The distribution range of P. stymphalicus includes the Ionian mainland, from the Acheloos to Mornos rivers, and most of the Peloponnese, excluding the Evrotas and the headwaters of Alfios. The native range of Pelasgus marathonicus is the western Aegean mainland, from rivers near Athens to the Xerias river in the Pagasitikos Gulf. AMOVA showed that the genetic variance is slightly higher among than between populations. High F ST values indicated a pronounced genetic differentiation of the populations in both species. There was a high proportion of private haplotypes and a very small number of shared haplotypes between populations in both species, which indicates uniqueness of each population and their susceptibility to human-induced changes.
... However, the responses of candidate metrics to human impacts were weak and highly variable in IRES due to low local species richness and the prevalence of endemic species, which prevented metric selection. Instead, each country within the Mediterranean ecoregion developed indices effective at either a national scale (Zogaris et al., 2018) or designed specifically for one or few river basins (e.g. Magalhães et al., 2008;Aparicio et al., 2011;Hermoso et al., 2010). ...
Chapter 3 of the Intermittent rivers and ephemeral streams: what water managers need to know. Technical report – Cost ACTION CA 15113
... However, the responses of candidate metrics to human impacts were weak and highly variable in IRES due to low local species richness and the prevalence of endemic species, which prevented metric selection. Instead, each country within the Mediterranean ecoregion developed indices effective at either a national scale (Zogaris et al., 2018) or designed specifically for one or few river basins (e.g. Magalhães et al., 2008;Aparicio et al., 2011;Hermoso et al., 2010). ...
Intermittent rivers and Ephemeral Streams (IRES) are river water bodies characterised by temporary flow. They are widespread across the EU and a significant proportion of them is expected to increase due to climate change scenarios and rising water demands.
The purpose of this handbook is to help water managers to understand the natural processes prevailing in IRES and their importance for biodiversity and local communities in order to better manage them.
Since it is widely accepted that these types of systems have been up until recently neglected, the transfer of knowledge from scientists to water managers is required for their proper ecological status assessment, and crucial for their protection and restoration. Therefore, this SMIRES handbook will also bring about a better understanding of IRES, and will provide for the provision of tools needed for managing them in the best possible way.
Eight case studies, located in different countries, aim at illustrating different experiments of managing IRES where the knowledge previously presented in the handbook is needed and used. These experiments do not claim to be exemplary practices to be reproduced everywhere but instead give insights of what could be done, what should be strengthened and what should be avoided in specific contexts. The issues are various: restoration of habitats, reduction of erosion, flood prevention, mitigation of hydrological drought, raise of groundwater levels, etc. Among the lessons learned, all case studies insist on the importance of increasing people awareness about the ecosystem services associated with IRES and encourage local stakeholders to involve themselves in restoration projects of IRES. A specific attention to project monitoring is also pointed out to assess the outputs and to encourage other initiatives to be taken.
... The physicochemical characteristics of sampling locality are presented in Table 1. Overall, the physicochemical quality of the sampling site was good, as classified according to the physicochemical quality index (Skoulikidis et al., 2006); however, fish-based assessments of the lower Erythropotamos water body have indicated moderate to poor conditions in recent years, mainly due to degradation from water abstraction, hydromorphological changes and seasonal eutrophic conditions that affect natural fish assemblages (Zogaris et al., 2018). Although the potential use of Corbicula species for biomonitoring purposes has been suggested (e.g. ...
This contribution presents the first record of the Asian clam Corbicula fluminea Müller, 1774 in Greece. The species was collected in Erythropotamos River (Reka Luda Луда река), one of the main tributaries of Evros River (classical name of the Maritsa river), thus being the southernmost record of this invasive bivalve in the Balkan Peninsula. The most likely entry source of C. fluminea in Greece is through active or passive downstream drift through the Bulgarian part of Erythropotamos River, which is shared between Bulgaria and Greece. Special attention is now required to assess the invasion extent of the Asian clam in the entire Evros basin and adjacent river basins of Bulgaria and the Aegean basins of Greece and Turkey.
... These methods were able to detect, not only water quality impacts, but also environmental disfunctions related with insufficient discharge ( (Santos & Caramaschi, 2007. In these cases of scarce or non-existent historical data, reference conditions can be formulated on the basis of potential fish distribution modelling (Canning, 2018;Zogaris et al., 2018) or expert judgement (Pardo et al., 2012;Virbickas & Kesminas, 2007). In either case, it is much more accurate to formulate reference conditions for homogeneous functional river types. ...
Defining environmental river types is an essential step in the development of accurate fish‐based methods (IBI, Index of Biotic Integrity) to assess the environmental quality of aquatic ecosystems. In this study, the environmental typology of the rivers and streams in the region of Chapada Diamantina was developed. Thirty‐five sampling sites representative of the upper Paraguaçu River and its main tributaries were characterized to characterize the fish assemblages and abiotic environmental descriptors. A cluster analysis based on fish species CPUE was performed to define a first biological typology. Then, a discriminant analysis model was developed to select the environmental descriptors that explained the fish‐based river types. The model selected 11 environmental variables and classified 91% of the cases. The river typology defined in this study will be used for the development of an IBI to assess the ecological status of the Chapada Diamantina rivers. It is expected that both the typology developed here and the future IBI will provide important and useful tools to develop and apply nature conservation‐oriented management schemes in the Chapada Diamantina aquatic ecosystems.
... metrics, as proxies of the age composition of fish communities, were proven to be efficient indices during an assessment of the Júcar River in the Mediterranean region using fish assemblages (Aparicio et al., 2011), whereas size-weight-based metrics were not included in our final index due to poor responsiveness and repeatability. The discrepancy in sizeweight-based metric performance between central China and the Mediterranean region can be explained by the region-specific fish compositions (Zogaris et al., 2018). Most endemic species (e.g., brown trout) that are distributed in Mediterranean cold streams are intolerant species, which are strongly influenced by human pressures, and show stable responsiveness to ecological status (Logez and Pont, 2011;Skoulikidis et al., 2011). ...
The multimetric index of biotic integrity (IBI) based on fish assemblages has been widely used to monitor aquatic ecosystem status in headwater streams. However, the application of the IBI has generally been biased by the low number of species and natural altitudinal gradients in these systems. To overcome these limitations, taxonomic distinctness and size-weight-based indices were integrated into our candidate metric pool, and calibration was performed to reduce the effects of the altitudinal gradient on the metrics in our study. Eighty-two sites in six headwater streams along a typical high altitude gradient and with low species richness were sampled. Eighty-three candidate metrics were selected to develop our IBI (IBI-Han) based on the systematic screening method. Six metrics based on taxonomic distinctness, habitat, tolerance guild, reproductive guild and trophic guild were finally retained in the IBI-Han: average taxonomic distinctness, percent rheophilic species, percent tolerant species, percent biomass of water column species, percent lithophilic species, and percent carnivorous species. The IBI-Han performed well in discriminating anthropogenic disturbances not only at training sites but also at testing sites, which suggests that our method could provide a reliable evaluation of the condition of headwater stream ecosystems. Among the six rivers, the Jinshui River showed relatively healthy ecosystem status, while the other five streams were disturbed by various human activities. Our work highlights that taxonomic distinctness indices are robust biomonitoring indices that can be combined with other functional indices to assess high altitude gradient streams in the upper Han River. We believe that the process of developing the IBI-Han could be regarded as a reference for managing headwater streams in other regions of China or in other states.
... These species are endemic of the Balkan rivers and the most abundant or the only fish species, in the upper section of the Drosopigi stream. Both fish species have been negatively impacted from hydromorphological alterations and illegal water abstractions (Barbieri et al., 2015), while they both being rheophilic, potamodromous species that require specific rheolithophilic conditions for reproduction (Zogaris et al., 2018). Nevertheless, Barbus balcanicus is considered to have a lower response to hydromorphological changes than the cold-water trout species. ...
In this study, a state-of-the-art approach in modelling fish habitats, using high-resolution
topographical data, obtained from Unmanned Aerial Vehicle (UAV), was applied. Habitat Suitability Indices
are used to predict how changes in discharge affect instream fish habitats. HSIs regarding depth and velocity for
two size classes (small sized fish 5 –15 cm, Total Length (TL) and large sized >15 cm TL) of Salmo pelagonicus
and Barbus balcanicus, were used, in combination with a two-dimensional (2D) hydraulic-hydrodynamic model,
for the estimation of the Weighted Usable Area (WUA) in a mountainous stream. Computational mesh and/or
DTM resolution selection may influence the accuracy of WUA results, especially in boulder and cobble-bed
streams with complex habitat structures. The aim of the study is to examine the sensitivity of various hydraulichydrodynamic modelling geometry configurations on WUA at ungauged or poorly gauged streams. Comparisons
of three different geometry configurations: 1) Identical computational mesh and DTM resolution (SensComb),
2) Finest computational mesh resolution combined with different DTM resolutions (SensDTM), 3) Finest DTM
resolution combined with different computational mesh resolutions, as part of 2D hydrodynamic modelling,
were applied to test the differences in WUA (SensMesh). WUA maps were generated for both fish species and
class sizes for each modelling geometry configuration and compared to each other for assessing the sensitivity
of the two-input data (computational mesh and DTM). Results provided by both indices, and their spatial
distribution indicated the optimal DTM and computational mesh resolution as well as the sensitivity of a specific
hydraulic-habitat model on them.
... The ways fish use "Mediterranean small river-mouths": Observations from Greece and Cyprus. 8th European Coastal Lagoon Conference, Divani Palace Acropolis, Parthenonos 19-25, Athens -Greece.Zogaris, S., Tachos, V., Economou, A.N., Chatzinikolaou, Y.,Koutsikos, N. and Schmutz, S., (2018). A model-based fish bioassessment index for Eastern Mediterranean rivers: Application in a biogeographically diverse area. ...
Hellenic Centre for Marine Research (HCMR) and National Centre for the Environment and Sustainable Development (NCSD - EKPAA) support the icthyological research, planning and development for Greece's first storm drain marking "yellow fish" campaign. The project is headed by Stamatis Zogaris of the Institute of Marine Biological Resources and Inland Waters.
... These hydrographic units are defined as semi-isolated and isolated river and lake basin areas; first conceived as inventory units by Economou et al. [23]. We chose to include only hydrographic units where we assume there is a complete native fish assemblage data-set available based both on wideranging bibliographic review and recent sampling, including repetitive sampling (in different periods or year) by us and our colleagues [49,50]. Moreover, the field surveys (primarily utilizing electrofishing methods) were based on standardized procedures [51] and sampling usually targeted river bioassesment. ...
Freshwater fishes are key indicators for delineating biogeographical maps worldwide. However, controversy in regional-scale ichthyogeographic boundaries still persists, especially in areas of high species endemicity, such as in Greece. One problem concerns the taxonomy of the fishes because there have been extensive changes, mainly due to an increased splitting of species in recent years in Europe. Here, we explore why ichthyogeographic boundary disagreements and uncertainties in region-scale biogeographical units persist. We compare cluster analyses of river basin fish fauna in Greece using two taxonomic datasets: the older fish taxonomy (from 1991) and the current taxonomy that now follows the phylogenetic species concept (PSC), which has become widely established in Europe after 2007. Cluster analyses using the older fish taxonomy depicts only two major biogeographical regional divisions, while the current taxonomy defines four major regional divisions in mainland Greece. Interestingly, some older maps from the pre-PSC taxonomy era also similarly show four ichthyogeographic divisions in Greece and we can assume that the older biogeographical work did not solely use numerical taxonomy but followed an expert-guided synthesis; the older regional definitions have persisted quite well despite radical changes in Europe's fish taxonomy. Through the prism of biodiversity conservation planning, we hope this review may help identify ways to help standardize policy-relevant biogeographical mapping.
... This dispersal pathway concerns species introduced from Bulgaria's Danubian and Black Sea basin freshwater fauna. In recent years another non-native Ponto-Caspian goby, the Pontian monkey goby Neogobius fluviatilis (Pallas, 1814) was documented in Bulgarian (Stefanov et al., 2008) and Greek parts of the Evros basin (Zogaris and Apostolou, 2011) but despite several sampling visits, the population in Greek waters was not re-located (Economou et al., 2016;Zogaris et al., 2018) and no new non-native gobies were recorded in this river until now. ...
The discovery of the racer goby Babka gymnotrachelus in the transboundary Evros river basin, collected on September 10th 2018 at two locations is reported. This is a new addition to the non-native ichthyofauna of Greece and the Aegean Sea drainages, and it is the second non-native Ponto-Caspian goby to enter this river. Boat-based electrofishing sampling, following the EU Water Framework Directive monitoring program, provides first evidence of what is presumed to be a recently established population; most of the 13 collected specimens are juveniles and the species has not yet been located in the river's tributaries. Further study and international cooperation in monitoring and management of this and other alien species in the Evros are proposed.
... The encountered migratory species include potamodromous species (Barbus prespensis, Chondrostoma vardarense, Luciobarbus albanicus etc.) that migrate within the river system, and long-distance migrants which also need access to the sea (Anguilla anguilla, Alosa sp., Mugil sp., Dicentrarchus labrax etc.) (Kottelat & Freyhof 2007, Zogaris et al. 2018). The European sea bass, Dicentrarchus labrax, is a truly marine fish, but is euryhaline at all developmental stages (Pickett & Pawson 1995) and is able to grow and thrive in freshwaters (Chervinski 1974). ...
Knowledge and understanding on habitat ecology of fish is a basic step for developing management and conservation measures. We investigated fish species distribution and fish habitat partitioning at the Poçemi floodplain area of the Vjosa River. The study was conducted during one week in April 2017. Sixteen species, including several protected and endangered species were captured. The results of this study provide first insights of fish habitat use for the river Vjosa, exhibiting distinct fish assemblages of different aquatic habitat types. The heterogenic habitat configuration provides conditions for a variety of ecological guilds and consequently significantly increases the recorded fish biodiversity. Finally, the results are discussed with regard to the life cycle of riverine fish and different seasonal and daily habitat demands and migration patterns.
... The Vjosa River represents a biodiversity hotspot of Albania, hosting ideal aquatic habitats for various migratory fish species. These include potamodromous species (Barbus prespensis, Chondrostoma vardarense, Luciobarbus albanicus etc.) that migrate within the river system, and long-distance migrants which also need access to the sea (Anguilla anguilla, Alosa sp., Mugil sp., Dicentrarchus labrax etc.) (Kottelat & Freyhof 2007, Zogaris et al. 2018. The high abundances of the critically endangered European eel (Anguilla Anguilla) highlight the importance of an undisturbed longitudinal river continuum at the Vjosa at an European scale (Jacoby & Gollock 2014). ...
The paper provides an overview of the existing knowledge on biodiversity of the whole Vjosa catchment. Besides major gaps in knowledge, the Vjosa catchment is one of the richest in Albania, sheltering a high diversity of habitats and species, most of them of international significance. A variety of protected areas is connected by the River Vjosa
and its tributaries and serve as important ecological corridor. Around 150 species of the already known flora and fauna species are listed in the Appendices of the Bern Convention. More than 15 priority habitat types of European interest have been identified (Habitat directive – NATURA 2000), as well as 7 habitat priority types (EUNIS, IPA) of high floristic value. Many habitats of the Vjosa area are included in the Directive 92/42/EEC adopted in May 1992: the woody riparian vegetation along river floodplains, with the dominant species Platanus orientalis, Populus alba, Salix spp., Alnus glutinosa, Fraxinus angustifolia, Quercus robur, and Ulmus minor; moreover, chasmophytic vegetation is documented in the area,; coastal sandy dunes with Ammophila arenaria and other rare plant
species; The Vjosa Delta-Narta wetland area is mentioned as the second most important site for birds in Albania, with about 80 species recorded. The area is known as the main wintering site for many water bird species including the Greater Flamingo (Phoenicopterus roseus) and Audouini’s Gull (Ichthyaetus audouinii). The Dalmatian Pelican (Pelecanus crispus) frequently occurs in the Vjosa Delta zone. Therefore, a special attention
must be paid to future hydropower development plans. Conservation actions must address threats to water quantity and quality over wide areas upstream of threatened habitats and species. Based on the presented data the floodplains of the Vjosa River from Tepelena to Mifoli are considered as a potential protected area, specifically a proposed
riverscape National Park.
... Bibliographic data of freshwater fish species occurrences were collected, for 117 major hydrographic units ( Figure 1); these units are defined as semi-isolated and isolated river and lake basin areas (see Economou et al. 2007, Koutsikos et al. 2012). Data on fish species presence/absence per major hydrographic unit were also confirmed by sample data from a dataset of recent electrofishing sampling (presented in: Zogaris et al. 2018). ...
Freshwater fishes are widely used as key biogeographic indicators for developing freshwater regionalization maps, and several such freshwater “ecoregional schemes” have been developed worldwide. Controversy and uncertainty in regional ichthyogeography still persists in Greece. One problem concerns recently increased splitting of previous sub-species entities. In this work we compare biogeographic hydrographic basin cluster analyses of two taxonomic datasets, the older fish names from 1991 and the current names that now follow the Phylogenetic Species Concept which have become valid during the last decade. The taxonomic changes during the last 30 years in Greece’s freshwater ichthyofauna is remarkable: of 117 freshwater species examined in our analysis more than half have changed names or been added as new to the country’s checklist. The classification analyses of river basin hydrographic units using fish presence shows remarkable changes in major ichthyofaunal boundaries (faunal distribution break lines). For mainland Greece the older fish taxonomy depicts two major biogeographical regional divisions while the recent taxonomy provides four major regional divisions. The recent taxonomy divisions are closely corroborated by the dominant current biogeographic freshwater ecoregion scheme.
Technical report concerning Pelasgus marathonicus conservation and restoration in Attika Greece.
Rivers of the Boreal Uplands vary greatly in size and hydrological regime. The most typical feature of all rivers is their importance in valleys as landscape elements and as key economic centers. To reduce perturbations and maintain catchments for coming generations, 388 parts of or entire catchments are protected through a special Protection Plan for Watercourses, and 52 rivers (represent 75% of the Atlantic salmon biomass in the region) have been selected as National Salmon Watercourses to protect areas for the wild Atlantic salmon. At present, two major challenges exist. A major interest in building small hydropower schemes (installed effect <10 MW) has taken place in recent years. The second challenge is related to floods and the use of land near river corridors. Problems arise in areas where the river corridor is a major part of the area available for human activity.
This technical report surveys the development of conservation objectives for all fish species community concern in Greece based on the EU Habitats Directive. 61 species of fishes relevant to Annex II and four additional species are presented. For each speceis the report presents National Conservation Objectives and provides the first assessment of Conservation Priorities and a revision/update of EU Natura 2000 Site Conservation Objectives (In Greek).
The design and implementation of appropriate management actions to tackle the spread and negative impacts of non-indigenous fish species (NIFS) in freshwater ecosystems still remains a complex task. In an effort to address the limitations of current managerial approaches, our study develops and applies a classification framework to define non-indigenous fish assemblage types (FATs) in Mediterranean riverine ecosystems and identifies the linkage with various regional, local, biotic and abiotic environmental factors. This framework contributes to a pre-invasion stage screening and to the design of effective type-specific post-invasion management actions dealing with specific NIFS assemblages. A network analysis was applied in order to extract NIFS community level information from 393 samples obtained from 51 river basins of Greece, while a multivariate ordination analysis was conducted to detect the factors best explaining the structure and distribution of FATs. The association patterns of the study's inputs and outcomes are illustrated through an alluvial diagram, providing insights across different spatial scales. In total, five FATs were generated where the major NIFS contributors of average similarity within each modularity class revealed the key indicator species (Gambusia-FAT; Carassius/Lepomis-FAT; Pseudorasbora-FAT; Salmonids-FAT and Carp-FAT). Overall, the identified FATs varied spatially, indicating different community structure, mainly based on the diverse habitat preferences and life-history traits of indicator species. Alien FATs were mainly distributed within large and transboundary rivers, while Translocated and Salmonids FATs mostly occupied ecoregions with relatively depauperate faunas and often in biodiversity hotspots. The results of this study can identify conservation priorities within FATs, inform specific-type post-invasion management actions tackling NIFS, while in addition may provide valuable information for protecting high-priority water bodies before invasion.
Healthy river ecosystems can provide fundamental ecological services for human survival and social development. However, previous studies that have sought to assess river ecosystem health have primarily focused on individual biological communities rather than on all aquatic communities and have been based on a single-index assessment method, thereby leading to large uncertainties in the results. In this study, we developed a new framework for the integrated assessment of aquatic ecosystem health based on the principal communities of fish, zoobenthos, phytoplankton, and zooplankton in rivers. An index of biotic integrity was used to evaluate the health of fish and zoobenthos communities, and a diversity index was used to evaluate the health of zooplankton and phytoplankton communities. To integrate the health assessment results from these four communities, a quantile normalization method was developed, where uncertainties in assessments obtained using the diversity index were well compensated for by the assessments obtained using the biotic integrity index. The framework was then applied to a pilot city, which is being constructed as a civilized freshwater ecological city in China. The results were then compared with those previously obtained based on the single-community method. Using this new framework, we found that the aquatic ecosystem health changed regularly in space and over time. Large differences were detected among the assessments of the four individual communities based on the single-community method, with the health score determined using phytoplankton being the highest, followed by that of zoobenthos, zooplankton, and fish, which made it difficult to reach a definitive conclusion regarding aquatic health status. The integrated assessment framework presented in this study successfully overcame the narrow perspective of the single-community method, thereby reducing uncertainties in the assessments based only on a single diversity index, and instead provides a comprehensive view of the status of aquatic ecosystem health. Thus, this integrated framework could assist river managers and stakeholders in developing comprehensive strategies for ecological restoration and water resource management and could become a key research tool for the health assessment and rehabilitation of aquatic ecosystems globally.
The paper provides an overview of the existing knowledge on biodiversity of the whole Vjosa catchment. Besides major gaps in knowledge, the Vjosa catchment is one of the richest in Albania, sheltering a high diversity of habitats and species, most of them of international significance. A variety of protected areas is connected by the River Vjosa
and its tributaries and serve as important ecological corridor. Around 150 species of the already known flora and fauna species are listed in the Appendices of the Bern Convention. More than 15 priority habitat types of European interest have been identified (Habitat directive – NATURA 2000), as well as 7 habitat priority types (EUNIS, IPA) of high floristic value. Many habitats of the Vjosa area are included in the Directive 92/42/EEC adopted in May 1992: the woody riparian vegetation along river floodplains, with the dominant species Platanus orientalis, Populus alba, Salix spp., Alnus glutinosa, Fraxinus angustifolia, Quercus robur, and Ulmus minor; moreover, chasmophytic vegetation is documented
in the area,; coastal sandy dunes with Ammophila arenaria and other rare plant species; The Vjosa Delta-Narta wetland area is mentioned as the second most important site for birds in Albania, with about 80 species recorded. The area is known as the main wintering site for many water bird species including the Greater Flamingo (Phoenicopterus
roseus) and Audouini’s Gull (Ichthyaetus audouinii). The Dalmatian Pelican (Pelecanus crispus) frequently occurs in the Vjosa Delta zone. Therefore, a special attention must be paid to future hydropower development plans. Conservation actions must address threats to water quantity and quality over wide areas upstream of threatened
habitats and species. Based on the presented data the floodplains of the Vjosa River from Tepelena to Mifoli are considered as a potential protected area, specifically a proposed riverscape National Park.
Based on a combination of intensive fieldwork for a period of thirteen years (2004–
2017), literature review and review of museum specimens, we hereby provide an updated
checklist of the fishes of Albanian part of River Vjosa. Our results show that
there are at least 31 species of fishes inhabiting the river system, of which 27 are native,
including eight species endemic to the Balkans. With 11 species, Cyprinidae are by far
the most specious family, followed by Mugilidae (five). Salmonidae and Acipenseridae
are represented by 2 species each. The remaining ten families are represented by a single
species. At least four species (Pseudorasbora parva, Oncorhynchus mykiss, Carassius sp., Gambusia holbrooki) were introduced into the Vjosa basin. The provided list includes
the distribution of each species in River Vjosa, as well as annotations referring to introductions, taxonomic-and their conservation status.
Contribution to the knowledge of longhorn beetle fauna in Albania (Coleoptera, Cerambycidae). The present paper reports on records of 72 longhorn beetle species in Albania. Chlorophoirus trifasciatus (FABRICIUS, 1781) and Certallum ebulinum (LINNAEUS, 1767) are new to the fauna of the country. Notices on Red List species and rare longhorn beetles such as Phytoecia vittipennis REICHE, 1877 and Oxylia duponcheli BRULLE, 1832, are presented too.
The aim of this report is to test if the Hellenic Fish Index (HeFI) is compliant with the completed MED-GIG intercalibration exercise and if that the instructions of the CIS Guidance Document no 30 (EU 2015) have been followed. In particular, we examined whether all relevant parameters indicative of the BQE "fish" are covered, class boundaries are set in line with the WFD’s normative definitions, the method is applicable for nearly all major river systems in mainland Greece, including the IC types R-M1, R-M2, R-M4 and R-M5, and that HeFI performs well in discriminating human pressures.
The Hellenic Republic is now using a state-wide assessment method for the BQE fish in rivers, the Hellenic Fish Index, HeFI (Tachos et al. 2016; Zogaris et al. in prep.). In Greece, since 2002, six fish-based assessment methods have been developed by scientists involved in fish-based bioassessment research and working within relevant EU projects (e.g. FAME, STAR).The Hellenic Fish Index (HeFI) was developed and tested during the last two years, within an international cooperation project involving Greek and Austrian scientists; a complete description of this new index is given in the Annex section, accompanying this report.
Man's activities have had profound, and usually negative, influences on freshwater fishes from the smallest streams to the largest rivers. Some negative effects are due to contaminants, while others are associated with changes in watershed hydrology, habitat modifications, and alteration of energy sources upon which the aquatic biota depends. Regrettably, past efforts to evaluate effects of man's activities on fishes have attempted to use water quality as a surrogate for more comprehensive biotic assessment. A more refined biotic assessment program is required for effective protection of freshwater fish resources. An assessment system proposed here uses a series of fish community attributes related to species composition and ecological structure to evaluate the quality of an aquatic biota. In preliminary trials this system accurately reflected the status of fish communities and the environment supporting them.
Variability in flow as a result of seasonal precipitation patterns is a defining element of streams and rivers in Mediterranean-climate regions of the world and strongly influences the biota of these unique systems. Mediterranean-climate areas include the Mediterranean Basin and parts of Australia, California, Chile, and South Africa. Mediterranean streams and rivers can experience wet winters and consequent floods to severe droughts, when intermittency in otherwise perennial systems can occur. Inter-annual variation in precipitation can include multi-year droughts or consecutive wet years. Spatial variation in patterns of precipitation (rain vs. snow) combined with topographic variability lead to spatial variability in hydrologic patterns that influence populations and communities. Mediterranean streams and rivers are global biodiversity hotspots and are particularly vulnerable to human impacts. Biomonitoring, conservation efforts, and management responses to
climate change require approaches that account for spatial and temporal variability (including both intra- and inter-annual). The importance of long-term data sets for understanding and managing these systems highlights the need for sustained and coordinated research efforts in Mediterranean-climate streams and rivers.
A wide-ranging river fish survey was executed in the summer of 2009 as part of the preparatory actions for the establishment of a monitoring programme for the EU Water Framework Directive (WFD). This was the first extensive electrofishing campaign for WFD standardised bioassessment in Greece and the experience and insights gained are used here to provide a review of fish-based assessment conditions and requirements in this country. The survey sampled 85 sites on 25 rivers throughout mainland Greece, collecting 70 species of freshwater fish. Quantitative site-based assemblage data is used for taxonomic and ordination analyses
revealing a strong biogeographic regionalisation in the distribution of the ichthyofauna. The structural and spatial organisation of the fish fauna using species-level and community-level data analyses is explored in three ecoregions where data was deemed sufficient. Transitions in community taxonomic composition among ecoregions were abrupt and concordant with geographical barriers, reflecting the influence of historical biogeographic processes. Community-based analysis revealed a substantial degree of variation in quantitative attributes of the fish assemblages among ecoregions. Key conclusions of this work are: (a) the fish-based bioassessment system must be regionalised to reflect biogeographic variation; (b) high faunal heterogeneity among ecoregions (taxonomic, structural), and to a lower degree among basins, constrains the transferability of bioassessment metrics and indices for explicit regions to other regional frameworks; (c) faunal depauperation in most of the study areas reduces the utility of functional bioassessment metrics and also limits the utilisation of rare species and the applicability of the classical form of the “Index of Biotic Integrity” concept. Recommendations to cope with these problems are discussed.
The Water Framework Directive includes fish fauna as one of the biological elements, jointly with aquatic flora and benthic invertebrates, to assess and monitor water and habitat quality. Successful implementation of the Directive depends in part on the development of reliable, science-based tools to directly assess biological conditions. Although fish have been used as ecological indicators for more than 30 years around the world, mainly in North America and more recently in Europe, few studies have been done in Mediterranean streams. Fish assemblages of the Mediterranean basin, similarly to other Mediterranean areas such as California, have particular characteristics that hamper IBI's development: few native species, poor knowledge of their ecological requirements, high number
JRC scientific and technical report
The use of fish as a Biotic Quality Element (BQE) to assess the ecological quality of inland waters is a requirement for the implementation of the EU Water Framework Directive (WFD). Mediterranean Islands pose special problems in applying fish-based indicators since they typically contain very few fish species, most often dominated by non-indigenous species. This is the case on the island of Cyprus where the problem is further exacerbated by the intermittent character of the existing lotic water bodies, most often with no long-term connection to the sea. There is also a widespread and complex anthropogenic modification of the natural conditions, namely related to water abstraction and damming. In addition there is a lack of background natural history research, further hampering the definition of reference conditions and therefore limiting the development of ecological quality indices. To explore the potential use of fish for bioassessment purposes in lotic water bodies on Cyprus a fish survey was conducted from 2010 to 2012 at 151 sites in 31 river basins, covering most of the environmental variability found in the island. Despite a high variability of fish-based biotic attributes at the sampled sites, the results indicate that some fish-based metrics can be applied on Cyprus, even when the natural variability is accounted for.
A major issue for water resource management is the assessment of environmental degradation of lotic ecosystems. The overall aim of this study is to develop a multi-metric fish index for the cyprinid streams of the Caspian Sea Basin (MMICS) in Iran. As species diversity and composition as well as population structure in the studied streams are different to other regions, there is a substantial need to develop a new fish index. We sampled fish and environmental data of 102 sites in medium sized streams. We analysed human pressures at different spatial scales and determined applicable fish metrics showing a response to human pressures. In total, five structural and functional types of metrics (i.e. biodiversity, habitat, reproduction, trophic level and water quality sensitivity) were considered. In addition, we used 29 criteria describing major anthropogenic human pressures at sampling sites and generated a regional pressure index (RPI) that accounted for potential effects of multiple human pressures.
Development, evaluation and implementation of a standardised fish-based assessment method for the ecological status of European rivers. Project description for FAME.
This paper presents the results of implementation of European Fish Index (EFI) in assessing the state of central Albanian river system that includes several water bodies: Rivers Shkumbini, Erzeni, Devolli, Osumi and Vjosa. Along with implementation of method following the FAME program, we specifically compares the different approaches developed in other countries and further to that discuss advantages and disadvantages. Also in case of Albania we tried to identify advances in the development of assessment methods, in time when country is planning to enter and follow the EU commitments. We do consider that in our case the major steps in case of method development, i.e. data requirements, identification of reference conditions, quantifying human pressures, selection of metrics, index calibration, index validation and practical way of method implementation. Following the Water Framework Directive (WFD) there is strong requirement for monitoring of fish fauna in rivers and other water bodies.
Following data analyses we develop an index for Albanian rivers (ARI) with priory advantages that ARI has been especially prepared for Albanian rivers and its possibility to indicate the human interventions, where other biological parameters are not so sensitive.
A preliminary Multimetric Index based on fish attributes developed for the Evrotas River in Southern Greece. This is the third such fish-based index developed by the inland waters ichthyological team of the Hellenic Centre for Marine Research (HCMR).
Running water ecosystems of Europe are affected by various human pressures. However, little is known about the prevalence, spatial patterns, interactions with natural environment and co-occurrence of pressures. This study represents the first high-resolution data analysis of human pressures at the European scale, where important pressure criteria for 9330 sampling sites in 14 European countries were analysed. We identified 15 criteria describing major anthropogenic degradation and combined these into a global pressure index by taking additive effects of multiple pressures into account. Rivers are affected by alterations of water quality (59%), hydrology (41%) and morphology (38%). Connectivity is disrupted at the catchment level in 85% and 35% at the river segment level. Approximately 31% of all sites are affected by one, 29% by two, 28% by three and 12% by four pressure groups; only 21% are unaffected. In total, 47% of the sites are multi-impacted. Approximately 90% of lowland rivers are impacted by a combination of all four pressure groups.
The salmonid rivers in Bulgaria are characterized with naturally poor species composition of the ichthyocenoses what makes the existing fish indices based on the species richness as an indicator inapplicable for
ecological quality assessment.
An algorithm is proposed for assessment the ecological status of all trout rivers within the both Eco-region
12 and Eco-region 7 according WFD. Ten ichthyologic parameters were used: total number and biomass
of ichthyofauna, total number, biomass and number of size-age groups of the trouts of genus Salmo, percentage in number and number of the size-age groups of Bullhead (for Danube tributaries), percentage
in number of cyprinid species, percentage in number of the introduced species, health status of fish community. The values of the used parameters were organized in four ranges with respective rates 0, 1, 3, and
5. The integrated Trout River Index (TRI) was calculated as the score of the rates. The ecological quality
assessment was made through comparison of the values obtained with the referent values of TI taking in
account the river type.
The proposed algorithm was tested for ecological quality assessment of salmonid river stretches within
the watersheds of both the Danube River and Aegean Sea.
Published technical report on the development of an ichthyological multimetric index for ecological status assessment of Greek mountain streams and rivers. A project conducted by the Hellenic Center for Marine Research – Institute of Inland Waters / Hellenic Ministry for Development. This is the Main Document: 166 pp. Another document with data sets in the form of Appendices (189 pp) should also accompany this work. This is the first published fish-based index for Greece.
Streams and rivers in mediterranean-climate regions (med-rivers) are subjected to sequential, yet contrasting hydrologic disturbances of drying and flooding. Although seasonally predictable, these disturbances can vary in intensity and duration within and among mediterranean-climate regions (med-regions). Consequently, med-rivers differ in the permanence of their aquatic habitats. To persist, species have acquired matched resistance and resilience adaptations. They gain resistance either by enduring the stress or avoiding it. Community recovery (or resilience) is achieved with cessation of hydrologic stress that permits maximization of re-colonization and reproduction. Endurance strategies are usually disturbance-specific, but avoidance enables organisms to cope with both drying and flooding, and is the prevalent resistance strategy. Correspondingly, community persistence depends to a large extent on the integrity of refuges, an aspect that has so far been little explored. Existing information suggests that seasonal community succession becomes more pronounced with increasing aridity and declining water permanence. The invertebrate community in semi-arid med-rivers can therefore undergo succession through three to four identifiable assemblages, whereas in perennial streams the difference between wet and dry period assemblages is smaller. Community turnover is influenced by the intensity of the hydrologic disturbances and varies between wet and drought years.
We classified homogenous river types across Europe and searched for fish metrics qualified to show responses to specific pressures (hydromorphological pressures or water quality pressures) vs. multiple pressures in these river types. We analysed fish taxa lists from 3105 sites in 16 ecoregions and 14 countries. Sites were pre-classified for 15 selected pressures to separate unimpacted from impacted sites. Hierarchical cluster analysis was used to split unimpacted sites into four homogenous river types based on species composition and geographical location. Classification trees were employed to predict associated river types for impacted sites with four environmental variables. We defined a set of 129 candidate fish metrics to select the best reacting metrics for each river type. The candidate metrics represented tolerances/intolerances of species associated with six metric types: habitat, migration, water quality sensitivity, reproduction, trophic level and biodiversity. The results showed that 17 uncorrelated metrics reacted to pressures in the four river types. Metrics responded specifically to water quality pressures and hydromorphological pressures in three river types and to multiple pressures in all river types. Four metrics associated with water quality sensitivity showed a significant reaction in up to three river types, whereas 13 metrics were specific to individual river types. Our results contribute to the better understanding of fish assemblage response to human pressures at a pan-European scale. The results are especially important for European river management and restoration, as it is necessary to uncover underlying processes and effects of human pressures on aquatic communities.
The current ecosystem paradigm in limnology is represented by the cold temperate, stratifying lake and the single-channelled river. However, the variety of inland water ecosystems is much higher, and so is the ecological complexity of many of them. Most Mediterranean limnosystems are quite distinct from the contemporary limnological paradigm. This overview will deal with the striking and exciting differences between Mediterranean and other temperate limnosystems. For example, most are very small, their catchment area is much larger than their size, and they experience both a longer vegetation period and a strong seasonality in water supply which occurs outside the hot season, often from groundwater sources. In addition, we encourage research on the often poorly known limnological processes taking place in Mediterranean regions by pointing at insufficiently covered research fields. Furthermore, competition for water among different users, arising from population increase in fertile and/or tourist areas, is certainly limiting the ability of many Mediterranean limnosystems to survive at present and in the near future, particularly in the face of the harsher environmental conditions that climatic change is triggering. A new paradigm on Mediterranean limnology is thus necessary. This will enable us to predict and mitigate more accurately the unstoppable effects of man-made change in these beautiful and still largely ignored ecosystems.
Community convergence across biogeographic ally distinct regions suggests the existence of key, repeated, evolutionary mechanisms relating community characteristics to the environment. However, convergence studies at the community level often involve only qualitative comparisons of the environment and may fail to identify which environmental variables drive community structure. We tested the hypothesis that the biological traits of fish communities on two continents (Europe and North America) are similarly related to environmental conditions. Specifically, from observations of individual fish made at the microhabitat scale (a few square meters) within French streams, we generated habitat preference models linking traits of fish species to local scale hydraulic conditions (Froude number). Using this information, we then predicted how hydraulics and geomorphology at the larger scale of stream reaches (several pool-riffle sequences) should quantitatively influence the trait composition of fish communities. Trait composition for fishes in stream reaches with low Froude number at low flow or high proportion of pools was predicted as nonbenthic, large, fecund, long-lived, nonstreamlined, and weak swimmers, We tested our predictions in contrasting stream reaches in France (n = 11) and Virginia, USA (11 = 76), using analyses of covariance to quantify the relative influence of continent vs. physical habitat variables on fish traits. The reach-scale convergence analysis indicated that trait proportions in the communities differed between continents (up to 55% of the variance in each trait was explained by "continent"), partly due to distinct evolutionary histories. However, within continents, trait proportions were comparably related to the hydraulic and geomorphic variables (up to 54% of the variance within continents explained). In particular, a synthetic measure of fish traits in reaches was well explained (50% of its variance) by the Froude number independently of the continent. The effect of physical variables did not differ across continents for most traits, confirming our predictions qualitatively and quantitatively, Therefore, despite phylogenetic and historical differences between continents, fish communities of France and Virginia exhibit convergence in biological traits related to hydraulics and geomorphology. This convergence reflects morphological and behavioral adaptations to physical stress in streams. This study supports the existence of a habitat template for ecological strategies. Some key quantitative variables that define this habitat template can be identified by characterizing how individual organisms use their physical environment, and by using dimensionless physical variables that reveal common energetic properties in different systems. Overall, quantitative tests of community convergence are efficient tools to demonstrate that some community traits are predictable from environmental features.
Physical and chemical monitoring of water bodies is relatively common. However, water resource assessment suffers from lack of integrative and reliable measures of the biotic condition of aquatic systems. This situation persists despite the fundamentally biological nature of water resource degradation. We examined three aspects of applying an index of biotic integrity (IBI) that uses attributes of fish communities to assess stream degradation: (1) relative contributions of individual metrics to the final IBI assessment; (2) effects of sampling effort on the IBI; and (3) effects of including young-of-year fish data on IBI computations. Relative contributions of individual metrics to IBI assessments varied substantially among data sets from Illinois, Ohio, and West Virginia, and variation in contributions reflected differences in ranges of metric scores and types of degradation being assessed. No metric was consistently best or worst at detecting degradation, and metrics did not appear redundant with respect to each other. The IBI scores increased with increasing length of stream sampled, largely due to increases in the number of species accumulated in fish collections. The IBI scores from short reaches were more variable than scores from long reaches; adequate sample reaches should contain several pool-riffle sequences. Exclusion of young-of-year fish from IBI computations typically reduced IBI scores by 2-10 units; the magnitude of reduction reflected the proportion of young of year in the samples. Species-richness metrics were affected more by exclusion of young of year than other metrics. The IBI appears to be broadly useful to water resource managers and, if used in conjunction with other measures of water and habitat quality, should provide a comprehensive approach for assessing resource quality.
Many countries, including Ireland, were ill-prepared for the requirements of the Water Frame- work Directive (WFD) regarding the use of fi sh as a biological element. Examination of archival data proved uninformative. Details of species composition, distribution and density were frag- mented and non-standard. No monitoring programme or strategic stock assessment existed, and information of the type required by the WFD was not available. This paper describes the research undertaken in Ireland since 2000 to deliver standardised WFD survey methods and protocols with which to create essential WFD-compliant data on fi sh communities in rivers, lakes and transitional waters. Three research projects, one in each surface water category, are discussed, as are initial developments towards fi sh-classifi cation schemes, surveillance monitoring, and participation and advances in the intercalibration process.
Species tolerances are frequently used in multi-metric ecological quality indices, and typically have the strongest responses to disturbances. Usually the tolerances of many species are based on expert judgment, with little support from empirical ecological or physiological data. This is particularly true for fish of Mediterranean-type rivers, in which there are many basin-endemic taxa with little information on basic life history traits. In addition, the apparent tolerance of native Mediterranean freshwater fish species to naturally harsh environments and their short-term resilience may mask responses to man-made pressures. Consequently, we evaluated different statistical techniques and procedures for quantifying Mediterranean lotic fish tolerances and compared expert judgment of species tolerances with empirically determined tolerance values. We used eight alternative approaches to compute fish tolerance values for the Mediterranean basins of SW Europe. Three types of approaches were used: (1) those based on the concept of niche breadth along an environment/pressure gradient (five models); (2) those based on deviations from expected values at disturbed sites as predicted by statistical models describing relationships between species and environmental variables (generalized linear modelling (GLM) and generalized additive modelling (GAM), two models); and (3) one model based on the relatively independent contributions of pressure variables to the data variation explained by statistical models. Tolerance estimates based on the used/available pressure gradient and the average general pressure value had the highest mean correlations with the expert judgment classification (mean r=0.4) and with the other approaches (mean r of 0.48 and 0.46, respectively). The high degree of uncertainty in tolerance estimates should be accounted for when applying them in ecological assessments. Results also highlights the need for better designed research to separate effects of natural and disturbance gradients on species occurrences and densities.
Because of natural environmental and faunal differences and scientific perspectives, numerous indices of biological integrity (IBIs) have been developed at local, state, and regional scales in the USA. These multiple IBIs, plus different criteria for judging impairment, hinder rigorous national and multistate assessments. Many IBI metrics are calibrated for water body size, but none are calibrated explicitly for other equally important natural variables such as air temperature, channel gradient, or geology. We developed a predictive aquatic-vertebrate IBI model using a total of 871 stream sites (including 162 least-disturbed and 163 most-disturbed sites) sampled as part of the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program survey of 12 conterminous western U.S. states. The selected IBI metrics (calculated from both fish and aquatic amphibians) were vertebrate species richness, benthic native species richness, assemblage tolerance index, proportion of invertivore-piscivore species, and proportion of lithophilic-reproducing species. Mean model IBI scores differed significantly between least-disturbed and most-disturbed sites as well as among ecoregions. Based on a model IBI impairment criterion of 0.44 (risks of type I and II errors balanced), an estimated 34.7% of stream kilometers in the western USA were deemed impaired, compared with 18% for a set of traditional IBIs. Also, the model IBI usually displayed less variability than the traditional IBIs, presumably because it was better calibrated for natural variability.
To test the hypothesis that different species have similar responses to local and regional environmental constraints, we modelled the occurrences of 13 species using a data set of 413 undisturbed river reaches. Three environmental descriptors were considered at the local scale (river slope, river width, and upstream drainage area) and three at the regional scale (mean annual and mean range air temperature and basin unit). Using multiple logistic regression modelling techniques, we correctly predicted the occurrence of 11 of the 13 retained species. The hierarchical partitioning analysis that we used allowed us to jointly consider all possible models in a multiple regression setting and to evaluate the independent explanatory power of each of our five environmental variables. We reject the hypothesis of a common species response to the environmental constraints. Species inhabiting upstream river reaches (bullhead (Cottus gobio), brown trout (Salmo trutta), minnow (Phoxinus phoxinus), and stone loach (Barbatula barbatula)) are more sensitive to basin unit. All species representative of downstream areas (barbel (Barbus barbus), dace (Leuciscus leuciscus), chub (Leuciscus cephalus), gudgeon (Gobio gobio), roach (Rutilus rutilus), bleak (Alburnus alburnus), and perch (Perca fluviatilis)) exhibit a positive continuous response to the drainage area, in agreement with the view of a continuous increase of local richness downstream. River slope is an important variable for all species. Main species habitat requirements are discussed for each species.
Longitudinal distributions and species diversity of freshwater fishes relative to physical factors (stream order, width, depth, elevation, river km and water temperature) were determined by seine and electrofishing collections made in four river dtainages (Aliakmon, Aoos, Axios and Strymon-Aggitis) in Greece from 13-24 June 2000. Twenty species of fishes (Anguillidae, Cyprinidae, Cobitidae, Balitoridae, Salmonidae and Centrarchidae) were taken in 27 collections. Stream order was found to be negatively correlated with elevation and gradient, and positively correlated with stream width and depth. Number of species was positively correlated with stream order, width and depth, and negatively correlation with elevation and gradient. Changes in species composition among stream orders were related more to replacement rather than addition of species. Low diversity per stream order identified in our study is not unlike those of harsh environments (e.g. streams in desert and boreal nvironments). Low species diversity per stream order (average: 2.1 in pt order; 8 in 5th order, respectively) is attributed to the small, isolated river drainages with limited water budgets in Greece, a result of the complicated geological history, and dry climate and low annual rainfall of the country. We propose that stream order alone can emulate an ecological unit and can be used to account for variation in species diversity along a river continuum except where an environmental feature such as a physical factor (e.g. stream length, gradient or stream width) changes rapidly within the same order. Stream order and stream width, the two most significant factors accounting for species diversity, are used to comment on the stream monitoring design based solely on stream order and elevation proposed by the European Environmental Agency for monitoring fish diversity in southern European Union countries (EU).
The Lake Kinneret watershed (LKW) is an important freshwater resource in Israel, providing a myriad of water-dependent ecosystem services. Presently, environmental monitoring of the LKW is focused mainly on water quality and quantity parameters, but neglect biology. To fill this gap, a reference-based biological monitoring scheme is being developed. This approach require a description of stream types, i.e., clusters of streams that naturally share similar environmental conditions, to help identify type-specific reference conditions and their associated communities. Here, we present the first stream typology for the entire LKW. Using a compilation of data layers of regional climate (precipitation and air temperature), local geology (volcanic, carbonic, and organic), and geomorphology (elevation, size, and slope), we have differentiated altogether nine stream types: small and mid-sized basaltic streams (41.6 and 2% of the entire catchment, respectively), small and mid-sized calcareous streams (36.4 and 2.9%), small organic streams (6.8%), and montane streams (6.5%). In addition, due to its size the Jordan River is divided into three section-types: the karstic upper Jordan (6.3 km), the organic section of the Hula Valley (13.1 km), and the basaltic canyon-like section (16.9 km that stretches between the Hula Valley and the Lake Kinneret). Although Israel is not obligated to comply with the EU Water Framework Directive, this work constitute an important step towards the development of the first bioassessment scheme for the LKW.
Aim: Human-induced loss of native species and introduction of non-native species have altered richness and composition of species assemblages world-wide. During the past 15 years many studies have focused on changes in taxonomic similarity and identified numerous yet often contrasting reasons for these changes. This study aims to quantify taxonomic changes in freshwater fish assemblages between the mid-19th century and today, while explicitly separating its different components and drivers. Location: Geographic Europe, 251 river basins > 2500 km². Methods: Pairwise catchment comparisons of historic and contemporary fish species inventories, with and without migratory fish, using Jaccard similarity; quantification of relative species turnover using a newly developed Reshuffling Index; determination of the threshold (here: number of catchments occupied) that displays how widespread a species must be to cause homogenization. Results: The European freshwater fish fauna changed profoundly since the mid-19th century. All river catchments exhibited an average net gain of 5.7 species, leading to an overall increase in faunal similarity across Europe of 3.1% (4.6% if migratory species are excluded). However, species turnover was much higher than indicated by the net gain. On average, 20% of the historic assemblages became reshuffled. The native catchment range size of an introduced species primarily determined its impact on taxonomic similarity change, irrespective whether it is translocated within or introduced from outside Europe and whether the species is of fisheries importance or not. Main conclusions: The concurrent use of multiple indices allowed disentangling the main components and drivers of taxonomic change. It became evident that prevention of intended or unintended species introduction will not lower the rate of taxonomic homogenization per se. However, most species actually caused taxonomic differentiation despite their range gain. All introduced species still considerably contributed to taxonomic change with potential negative effects on ecosystem functions.
Non-perennial rivers and streams (NPRS) cover > 50% of the global river network. They are particularly predominant in Mediterranean Europe as a result of dry climate conditions, climate change and land use development. Historically, both scientists and policy makers underestimated the importance of NRPS for nature and humans alike, mainly because they have been considered as systems of low ecological and economic value. During the past decades, diminishing water resources have increased the spatial and temporal extent of artificial NPRS as well as their exposure to multiple stressors, which threatening their ecological integrity, biodiversity and ecosystem services. In this paper, we provide a comprehensive overview of the structural and functional characteristics of NPRS in the European Mediterranean, and discuss gaps and problems in their management, concerning their typology, ecological assessment, legislative and policy protection, and incorporation in River Basin Management Plans. Because NPRS comprise highly unstable ecosystems, with strong and often unpredictable temporal and spatial variability – at least as far as it is possible to assess – we outline the future research needs required to better understand, manage and conserve them as highly valuable and sensitive ecosystems. Efficient collaborative activities among multidisciplinary research groups aiming to create innovative knowledge, water managers and policy makers are urgently needed in order to establish an appropriate methodological and legislative background. The incorporation of NPRS in EU-Med River Basin Management Plans in combination with the application of ecological flows is a first step towards enhancing NPRS management and conservation in order to effectively safeguard these highly valuable albeit threatened ecosystems.
The Water Framework Directive includes fish fauna as one of the biological elements, jointly with aquatic flora and benthic invertebrates, to assess and monitor water and habitat quality. Successful implementation of the Directive depends in part on the development of reliable, science-based tools to directly assess biological conditions. Although fish have been used as ecological indicators for more than 30 years around the world, mainly in North America and more recently in Europe, few studies have been done in Mediterranean streams. Fish assemblages of the Mediterranean basin, similarly to other Mediterranean areas such as California, have particular characteristics that hamper IBI's development: few native species, poor knowledge of their ecological requirements, high number of endemisms with a wide range of tolerance to environmental variations and many exotic species. This chapter summarizes our experience in developing fish-based tools in Catalonia. We discuss the challenges and difficulties to develop these approaches in Mediterranean streams. We show the IBICAT2010 as a fish-based assessment method suitable for the evaluation of the ecological status of Catalan rivers. Moreover, we assess size-related variables as a bioassessment tool because population size structure can provide insights into species-specific applications and management. Finally, we analyse the longitudinal connectivity throughout Catalan rivers and fish passes by using the index of river connectivity (ICF) specially designed to Catalan rivers.
Freshwater ecosystems are among the most affected by anthropogenic disturbances, and fish have several advantages for monitoring them, such as the response at larger temporal and spatial scales and its visibility to the society. This chapter summarizes our experience in developing fish-based indices in Catalonia. We describe some differences observed among crews in electrofishing captures and habitat assessments. We also analyzed the suitability of a single pass for conventional monitoring in the region and differences in capturability among sites and species by comparison with multiple passes and block nets. Furthermore, we summarize the results of two contrasting approaches, a site-and a type-specific one (IBICAT2a and IBICAT 2b) applied to Catalan rivers. The site-specific was not successful and further data are needed for its improvement.