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Developing a biotic river typology and defining reference conditions in the rivers of Greece: a spatially- based approach

A.N. Economou, S. Zogaris, S. Giakoumi, R. Barbieri & D. Petridis

Abstract

Developing a biotic river typology and reference conditions are vital components of ecological assessment using fish. In Greece, due to the absence of systematic monitoring data, fish sampling data from previous ichthyological surveys conducted primarily in the southern and western parts of the Hellenic Western Balkan ecoregion (Illies' ecoregion 6) were utilised. These surveys were undertaken for the purpose of fish conservation and were not designed with the prospect of ecological assessments. As a consequence, the sampling methodologies, the site selection criteria, the analytical procedures and the recorded parameters were not in line with the requirements of the WFD. A brief synopsis of the main environmental features of the Greek rivers which indicate a remarkable environmental heterogeneity is presented. Greece is a geographically fragmented mountainous country with a large number of medium and small sized rivers. Most rivers run through narrow mountain valleys that descend abruptly to the coast. Usually a mountain river becomes a lowland river very near its estuary. As a result many small and medium sized rivers have a flashy and erosive behavior and suffer from the lack of lowland riverine habitat. Lowland rivers are usually small; large floodplain rivers are very few, almost wholly restricted to northern Greece. Precipitation is irregularly distributed and hydrology varies remarkably among basins. Semi-arid regions and areas with seasonally arid conditions exist in parts of the south and southeast where localized karstic springs play an important role in enabling perennial water flows. Hence, hydrology, river geomorphology, biogeography and climatic conditions vary remarkably among basins and longitudinally along river courses. The major degradation types and their impacts on fish communities are reviewed. Throughout most of Greece, major impacts have resulted from water abstraction, which most often takes place mainly during the summer, and therefore coincides with the summer drought. The impacts of hydroelectric dams and other water exploitation practices and the operation of dams as reservoirs are ranked as next in importance, followed by reclamation and river management works, pollution, river bed substrate exploitation and the drainage of lakes and wetlands associated with rivers. Generally, streams and small rivers have been affected more adversely due to severe water abstraction (tapping of springs for domestic use and irrigation use) and their inability to buffer the harmful effects of pollutants in the way that large rivers can. The distributional patterns of 59 native freshwater species were used to investigate biogeographical relationships among river basins in the Hellenic part of ecoregion 6. For the purpose of this analysis the results of previous ichthyological investigations conducted by the NCMR were primarily utilised, however unpublished information on fish distribution was also used here to investigate biogeographical relationships. This analysis corroborates recent biogeographical proposals, but goes further in hypothesizing new biogeographical divisions in western and southern Greece. Paucity of data from some areas, taxonomic problems still evident in some taxa and a confusing pattern of faunal affinities and divergences make the use of the overall similarity of ichthyofaunas among drainage basins difficult to complete over the entire ecoregion. The results of statistical analysis on current fish distribution and fish community structure, supported by geological data and phylogenetic evidence, propose that the Greek part of Ecoregion 6 may be preliminarily divided into 5 freshwater fish subecoregions: (a) Macedonia-Thessalia, (b) Adriatic, (c) Ionian, (d) Evrotas and (e) Attiki-Beotia. Despite broad similarities, the rivers within the subecoregions Attiki-Beotia and Ionian show distinctive regions, which necessitate a further subdivision into “fish districts” for the interpretive purposes of this regionalization exercise. Linking ichthyological communities in reference sites with abiotic variables was proved to be a task beyond the abilities of the available dataset. Of the problems encountered, the most important concern the calibrated reference sites, some of which are poorly selected and not representative, others have sampling effect problems, and other sites proved to be more impacted than the screening process may have shown. Further complexities arise from the high degree of endemism and disjunct geographical distributions, which generate the need for a high level of typological discrimination. The extensive hydrological

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fragmentation and a great diversity of factors affecting the fish communities in Greek rivers, requires us to set reference conditions in a large number of strata. It is postulated that specifically designed research is necessary to arrive at a biologically meaningful typology scheme. Despite these difficulties, using available data and statistical analysis we identified some abiotic variables as potentially important for predicting community types; of which the most important in a nationwide scale seem to be basin size, altitude (a surrogate of temperature) and discharge (some other variables appear to be locally important also). Scarcity of appropriate data has prevented us to statistically justify the specific prominence of these variables and the significance of other abiotic variables, or to set biologically defensible boundaries among abiotic types. A preliminary top-down river biotic typology for the Peloponnesian part of the Ionian subecoregion, using combinations of these three variables only, is presented. During the work of WP3 candidate metrics were selected on the basis of knowledge of the fish fauna and of the aquatic systems of Greece, and the theoretical expectations for each metric were delineated. A general difficulty for establishing metrics for the development of a biologically-based multimetric index for ecological assessment in small rivers is that species richness is low and the fish communities in these rivers are dominated by tolerant species with wide ecological requirements. Multimetric approaches such as the IBI, using lots of metrics may not provide reliable assessment of ecological quality, because by adding a metric that is not biologically relevant or sensitive to the prevailing pressures less weight is given to more relevant metrics. We suggest that appropriate methods for the Greek low speciesrich rivers should rely on a limited number of metrics. For the case of flow regime disturbances the methods could include metrics for total fish abundance and biomass, abundance or proportion of sensitive species to flow reduction, and longevity or proportion of large age (size) groups, which seem to be intolerant to reduced flow. A short discussion is presented of the problems associated with the setting of reference conditions and building a multimetric index for ecological assessment using spatial methods in Greece.

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1. Introduction An analysis of the available ichthyological data was made with the objective to define a fish-based river typology and to identify reference conditions for FAME. The analysis was based on the following: (a) the results of previous ichthyological investigations conducted by the NCMR - Institute of Inland Waters – and (b) on published and unpublished fish data and biogeographical research. The NCMR’s field investigations concentrated on the southern and western portion of the Hellenic Western Balkan ecoregion (Illies' ecoregion 6), however sporadic data from the eastern portion are also available (Appendix 1, Map 1). The investigations were undertaken mainly for the purposes of endemic fish surveys and conservation assessments and they were not designed with the prospect of river ecological status assessments. As a consequence, the sampling methodologies, the site selection criteria, the analytical procedures and the recorded environmental and abiotic parameters were not in line with the requirements of the WFD, or adequate for the development of a multimetric index. The aims of this report are the following: 1. A synopsis of the characteristics of Greek rivers and a brief description of degradation types

in the scope of developing a spatially-based approach using a multimetric index for ecological assessment,

2. Initial development of a fish-based typology which centers on:

The definition of biogeographically-relevant subecoregions (regionalization) Linking ichthyological communities in reference (plus calibrated reference) sites with

important abiotic variables Provisional establishment of an abiotic typology for a portion of Peloponnese based on

system B using the top-down approach. The data available were not adequate (a) to develop a biotic typology and to link biotic river types with abiotic variables, nor to perform comparisons with typologies based on systems A and B, (b) to set reference conditions and develop a rating system. Scarcity of data from other Balkan counties also prevented an expansion of our analyses to the whole ecoregion 6. 2. Methods 2.1. Data utilised The NCMR dataset contains site-specific data from about 600 samples taken from 48 rivers of western Greece, the Peloponnese and the Island of Rhodes (most of these data have been stored in a PARADOX database). The usefulness of these data for river ecological assessments was evaluated and the samples that were deemed appropriate were selected for FAME. Due to problems in using and adapting existing data to the specialised requirements of the FAME database, data from only 83 samples belonging to 56 sites in 34 rivers could be utilised. Pressure criteria were used as a screening tool and 9 sites where selected as satisfying the reference criteria developed during FAME (Appendix 1, Map 2). Loosening the reference criteria (five variables, mean impact level <2), an additional number of 29 sites (calibrated dataset) were identified and used for establishing a fish-based typology. Additional fish data (literature, historical records) from Greek areas of ecoregion 6 not covered by the NCMR’s investigations were also used mainly for establishing subecoregions based on zoogeographic patterns.

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2.2. Data analysis 2.2.1. Characteristics of Greek rivers and description of degradation types Prevailing anthropogenic pressures and degradation types are described based on expert knowledge and the results of published reports and unpublished data. Impact levels of the priority pressure types in the sampling sites were described using histograms developed from an interrogation of the FIDES database. 2.2.2. Development of a biocoenotic typology The hierarchical framework towards a biocoenotic typology involves three major steps: (a) the establishment of subecoregions, focusing on broad zoogeographic patterns, (b) the identification of homogeneous communities, based on an analysis of fish data, and (c) the identification of relevant abiotic variables (and class boundaries within them) that determine “homogeneous communities”. The procedures and statistical tests utilised are briefly indicated below. 2.2.2.a. Fish-based subecoregion development Two statistical analyses were used to investigate biogeographical relationships among river basins: Sorenson group average cluster analysis and Twinspan analysis. The analyses were based on distributional patterns of 59 native exclusively freshwater species. Certain taxa where excluded because they are primarily estuarine or non-exclusively freshwater species (e.g. Acipenseridae, Alosa sp. Mugillidae). The widespread, nearly ubiquitous, eel (Anguilla anguilla) was also excluded from the analysis because it migrates via the sea and does not reveal biogeographical relationships. Biotically-relevant ichthyogeographical divisions were established by combining the results of the statistical analysis of available ichthyological data (i.e. fish species assemblages per basin) from all major rivers of ecoregion 6 (not only those included in the FAME database) with geological and phylogenetic data. The defined sub-ecoregions are probably adequate in creating an applicable regionalization needed for the development of a multimetric index for river bioassessments. Because of the high degree of endemism in western and southern Greece a further subregion, preliminarily labelled “fish district”, is delineated within the sub-ecoregions. 2.2.2.b. Linking biotic and abiotic data Due to the paucity of appropriate and systematically sampled biological data, a methodology involving the establishment of biotic river types and the identification of influential abiotic variables and class boundaries that describe these types could be undertaken. Instead, steps towards a typology that links biotic and abiotic data were made as following: Reference site data (plus calibrated reference sites) were analysed on the basis of abiotic and biotic characteristics. Five abiotic parameters (discharge class, altitude, gradient slope, air temperature and river basin size) and two biotic parameters (species richness and fish abundance, measured in numbers of fish caught per hectare) were isolated as important. These site attributes were analysed in the following ways: Principal Component Analysis was applied to determine the most influential abiotic

parameters. Cluster analysis of samples to define potential homogeneous sample groups. Box plots of

abiotic variables per group are displayed. One-way analysis of variance for the biotic parameters between groups is applied to find differences between group means.

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An attempt was finally made to establish relationships between abiotic attributes and biotic parameters. 3. Results 3.1. The characteristics and diversity of rivers in Greece Greece is a geographically fragmented, mountainous country with a large number of medium and small sized rivers. Most rivers run through narrow mountain valleys, have a flashy and erosive behaviour and descend abruptly to the coast. Usually a mountain river becomes a lowland river very near its estuary. As a result many small and medium sized rivers have very small or no floodplains and lack lowland riverine habitat. “Lowland” habitat conditions are often encountered in plateaus which create unique biota since their access to main courses may be blocked by gorges or other natural barriers (including karstic phenomena). Most catchments in western and southern Greece are dominated by carbonate rocks (average 60%) and mainly calcareous flysch and molasse deposits (average 24%) with lacustrine sediments also present (average 8%). Hydrochemically, the rivers in this area reflect the carbonate and lacustrine deposits and are characterised by high levels of conductivity (average 428 µS/cm), total hardness (average 367 mg/l CaCO3) and alkalinity (average 3.41 mval/l). In parts of central and eastern Greece, catchment geology is dominated by silicate rocks (average 60%) followed by carbonate rocks (average 24%). Hydrochemically, the rivers in this area show relatively low conductivity (average 297 µS/cm) and total hardness (average 172 mg/l CaCO3). Precipitation is irregularly distributed, ranging from 1200 mm annually in parts of western and central Greece to 300 mm in parts of the southeast coastal areas. Rain-shadow areas in the southeast mainland create pockets of seasonally arid conditions with high evapotranspiration rates and a long summer drought. Hydrology varies remarkably among basins and longitudinally along the river course, depending on geomorphological and local climatic conditions. Due to the predominance of calcareous geology in western and southern Greece, karstic springs are very important in providing steady flow regimes to relatively small rivers. Given the high diversity of conditions (hydrologic, morphological, climatic), the challenge is to develop a typology scheme that adequately partitions biological variability and yet utilises the necessary minimum number of abiotic variables. This is especially difficult in the Mediterranean calcareous streams of southern Greece which have a varied geomorphology and hydrology and their environmental conditions vary greatly both in space and time. 3.2. Major degradation types Environmental and ecological descriptions of several aquatic systems of the Greek part of ecoregion 6 (hydrology, geology, geomorphology, biological parameters, conservation status, anthropogenic pressures, etc.) have been provided by EKBY(1994), Economou et. al. (1999, 2001), and Skoulikidis et.al. (1998). According to these reports, major impacts on the aquatic ecosystems have resulted from water abstraction, which is especially important in the southern, eastern and insular part of the ecoregion and has dramatically altered many riverine habitats. Increased water abstraction takes place mainly during the summer, and therefore coincides with the summer drought. Streams and small rivers have been affected more adversely than large rivers, and some of the smaller ones are now almost completely tapped for their water supply during the dry period. Large rivers have also been impacted by the rapid drying-out of floodplain and riverine

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wetlands due to water abstraction and associated reclamation projects. These impacts have degraded many lowland reaches of medium-sized and larger rivers throughout Greece. Other important impacts are imposed by dam operation. Hydro-electric dams have been constructed in many large rivers of western Greece. Irrigation dams and weirs occur in most of the larger rivers, and more are under construction, in the face of increasing demands for irrigation and domestic use of freshwater. These water exploitation structures cause two major types of impacts: they fragment fish populations, acting as barriers to dispersal and gene flow; and they modify the water flow regimes causing morphological changes (such as erosion of the banks) and damage to the aquatic vegetation and benthic biological communities. Rheophilic species and species with narrow ecological requirements have been mostly affected due to destruction of their specialised habitats. Pollution (point-source and from agricultural run-off) constitutes an important threat in rivers of northern Greece, but in western Greece the impacts of pollution can be regarded a less critical pressure, relatively small when compared to the impacts generated by water abstraction and dam operation. Agricultural and urban pollution seems to degrade water quality mostly in small rivers or rivers suffering from overexploitation that cannot buffer the harmful effects of pollutants in the way that large rivers can. Other widespread types of impacts include wetland drainage, mineral exploitation of river beds and the introduction of alien plant and animal species. A summary of impact levels in Greece’s FAME sampling sites is exhibited in the histograms that show the distribution of five primary impact criteria (Appendix 2, Fig 1). With few exceptions, most sites are located in western Greece and this explains why the impact levels concerning Nutrient Organic Inputs are fairly good (Impact classes 1 and 2 dominate). The variables showing most environmental degradation are Hydrological Regime and to a lesser extent Morphological Condition. Connectivity is relatively good in the rivers sampled, especially at the segment scale. The averaged score shows that most rivers are in fairly good condition (38 sites have an average impact class of two or less) and if this was the only screening process used it would define a large number of sites with relatively minimal alterations. 3.3. Establishing a fish-based river typology The establishment of subecoregions is an important unmet need in Greece and this has dominated our work. The identification of biologically relevant abiotic variables (and their class boundaries) that determine distinct river segments with homogenous abiotic and biotic characteristics needs systematic survey data. The interrogation of the FAME dataset for Greece did not produce significant results. The systematic data needed for this work must include all potential representative river types and sampling site selection should carefully consider all major habitat types in rivers. It has become clear that in order to stratify the natural spatial variation within both longitudinal and macroscale among-basin perspectives much more fish sampling data are needed. 3.3.1. Establishing subecoregions 3.3.1.1. Historical background on fish biogeography The historical relationships and geological evolution of the rivers of Greece play an outstanding role in the complexity and diversity of the fish faunas of Greece. This aspect of fish biogeography and community ecology has only recently been unravelled in Greece. Work by ichthyologists has variously appointed parts of southern Greece to different biogeographic districts (Bianco, 1990; Economidis & Banarescu, 1991; Maurakis & Economidis, 2001; Maurakis et. al., 2001; Gretes & Maurakis, 2001). There seems to be consensus that the following two major aquatic biogeographical divisions exist in Greece: a) Ponto-Aegean, which includes only the north-

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eastern part of the ecoregion 6 (Hellenic Western Balkans) and part of the ecoregion 7 (Eastern Balkans) and b) Paleo-Hellas, which includes nearly all of the rest of ecoregion 6. These divisions are biogeographically distinct because mountain boundaries exist that place long-term barriers to fish dispersal and exchange of genetic information. These boundaries are: (i) the Pindos mountain range, which creates a northwest-southeast barrier that separates the rivers of the western part of ecoregions 6 from the large rivers of the north-eastern part of this ecoregion; and (ii) the Mount Othrys, which separates the latter group of rivers from the rivers of the Attiki-Beotia (central-eastern Greece). Attiki-Beotia is a diverse area which seems to be a true ‘genetic crossroads’, as species have presumably emigrated in from both from the north and from the west, however they have been isolated long enough to show differentiation and speciation. Note that the large rivers of the “Ponto-Aegean” (north-eastern) part of ecoregion 6 are very similar to the other rivers along the coast of Ecoregion 7 and presumably have been influenced by an ichthyofauna of Danubian origin. They can be characterised as species-rich rivers which may have been connected when sea levels where lower, during the Pleistocene. In contrast, the “Paleo-Hellas” (western) part of ecoregion 6 is highly diverse and biogeographically complex, hosting many local endemics and a relatively species-poor ichthyofauna in most catchments. An additional difficulty in establishing biologically relevant divisions is that many areas in central and south-eastern Greece are in a bioclimatic semiarid zone, where few species have survived prolonged drought episodes or recent human water abstraction impacts. So far it has been difficult to determine the relationships among major river drainages in the Peloponnese and to show from the current ichthyofauna the biogeographical affinities among some of these. The issue is rather clearer in the west coast of Greece, despite inherent variation in the ichthyofaunas among river systems. It is immediately apparent that the Illies’ ecoregional boundary between ecoregions 6 and 7 (the Axios/Vardar river, with a north-south axis, flowing through most of FYROM) does not separate biogeographically distinct ecoregions. The Axios river has and shares several qualities with the rivers of Illies’ ecoregion 7 and, along with the Rivers Strymon and Evros/Maritsa (in Ecoregion 7), it may be responsible for aiding migration of fish from the central and northern Balkans. It is also possible that this river may once have had a common confluence with other water bodies connected to the rivers of the coast of Ecoregion 7. Axios also shares a relatively similar fauna with three major rivers in its immediate vicinity which make up a large part of the north-eastern portion of ecoregion 6 (Rivers Pinios, Aliakmon, Loudias). Since Illies’ ecoregional boundaries have been adopted for administrative purposes, we have to place some other type of boundaries (e.g. subecoregional) to account for the distinct fish fauna in the north-eastern part of Ecoregion 6, which shows remarkable affinities to Ecoregion 7, but is markedly different from the rest of Ecoregion 6. Similar arguments hold for the portion of ecoregion 6 that extends to the islands along the Asian coast of the east Aegean Sea. Although the knowledge of the island’s fish fauna is still incomplete, on the basis of available evidence it is tempting to suggest that the eastern part of the Aegean sea shows greater faunal affinities to Asia Minor, and should possibly comprise a separate ecoregion. Since most of these islands are in very close proximity or have been connected to the Asian coast during glacial periods, the biotas of these islands (invertebrates, larger vertebrates, plants) have their origin in the Asia Minor fauna and flora. Presumably, Illies’ boundaries were affected by political bias, since these islands belong to Greece, despite their Asian biota. 3.3.1.2. Statistical description of fish assemblages

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Three approaches were employed to ascertain biotically relevant subecoregional divisions within ecoregion 6. The first is the cluster analysis of major Greek rivers of ecoregion 6 (22 major rivers and 59 fish species). The presence/absence of these species in the basin was employed. Much unpublished information was employed here to enable biogeographic boundary proposals. Only rivers hosting more than 3 primary freshwater fish species were included in the analysis and all estuarine species were excluded. This decision was made in an attempt to confine the analysis to native exclusively freshwater fish, which are deemed good indicators of the geological historical relationships among river basins. The results of this cluster analysis are shown in Fig. 2 of Appendix 2. The most distinct clusters are (a) the Kifissos river in Attiki-Beotia (central-eastern Greece), (b) the rivers Pinios, Aliakmon, Loudias and Axios in Macedonia-Thessalia (north-central Greece), and (c) a cluster with the primary rivers of western Greece. In this last cluster a distinct subcluster is formed by the Evrotas river, a river basin located in the extreme south-eastern part of the ecoregion. There are some divergences in the remaining rivers of the western Greece cluster and these should be attributed to relatively distinct fish assemblages within these river basins, which gives us the opportunity to define a “finer-grained” regional subdivision which we will call here the “freshwater fish district”. (Note that two rivers named Pinios exist in Greece, one in Thessalia and one in Peloponnese). The second approach is a Twinspan analysis using the same river and fish data (Appendix 2, Figs. 3, 4 and 5). This analysis shows distinct separation of the river Aoos in the north of the country (running from Greece into Albania) and of the Macedonia-Thessalia rivers of the northeast section of Ecoregion 6 (Pinios-Thes, Aliakmon, Loudias, Axios) from the remaining rivers of the ecoregion. The analysis also shows a distinctive fauna in the Attiki-Beotia rivers of central-eastern Greece (Kifissos, Sperchios). With the exception of the data for the Aoos river, these results are corroborated in the Sorenson’s Cluster analysis (Appendix 2, Fig.2). Unlike the cluster analysis, which places all rivers of western Greece into a big cluster, Twinspan separates these rivers into three groups: a) the rivers of the southern Peloponnese (Evrotas, Pamissos, Velikas, Karya, Peristeras, Neda), b) the large rivers of the former ‘greater Acheloos” (Acheloos and Pinios-Pelop), and c) the other rivers of the western mainland Greece, mostly lying in Ipiros, the northwestern section of ecoregion 6. The last approach used to identify assemblages was a cluster analysis of the fish species. This analysis groups together the most distinct fish species assemblages based on co-occurrence (Appendix 2, Fig. 6). Here, in contrast to the previous clustering of river basins, affinity among species assemblages takes precedence in the groupings. The fish species clusters established corroborate the relative distinctiveness of the fish faunas of the following areas: Evrotas, Attiki-Beotia, and Aoos. Interestingly, parts of this fish-based classification defines a grouping which includes species inhabiting the proposed Macedonia-Thessalia subecoregion; this is a very different assemblage than the rest of southern and western Greece. 3.3.1.3. Proposed subecoregions and fish districts Although the statistical procedures described above (section 3.2.1.2) give broadly similar zoogeographic groupings, some problems need to be resolved. What do we do when ichthyological information does not exist for a given geographical area or an area has only a few (often intermittently flowing) small streams with one or two species of fish? Fore example, large areas in the eastern part of the Peloponnese peninsula have only very small streams with very few species – should these areas be labelled as a separate subecoregion or a freshwater fish district within an existing subecoregion? Because of such problems relating to a lack of ichthyological

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information, and also taxonomic problems still evident in several taxa, we decided that parts of the map of subecoregions should remain blank. Another problem is that in some areas the statistical tests utilised do not reveal a consistent pattern of faunal affinities and diversities. Discrepancies appear especially in the western part of ecoregion 6. With regard to this problem we decided that for the final delineation of subecoregions and lower divisions we should also take into account phylogenetic data on species evolutionary affinities as well as geological evidence on the physical evolution of the Hellenic peninsula. Special attention was paid on the most ancestral components of the Greek ichthyofauna, which largely characterise the zoogeographic patterns. These components have been unaffected by secondary invasions and are determined primarily by geological history (barriers to, and routes for dispersal) and local speciation processes. The reason that we centered our attention to isolation levels determined by historical factors and phylogenetic processes is that we wish to interpret the influential role of geological events and biogeographical processes in the evolution of the Greek ichthyofauna, which is dominated by endemic species, many of which have very restricted distributions. Zoogeographical differences that reflect features of modern environments (e.g. climatic) are not considered here, however they can be accounted for in subsequent discrimination levels of the procedure for establishing a typology scheme. The results of statistical analysis on current fish distribution and fish community structure, supported by geological data and phylogenetic evidence, propose that Greece’s Ecoregion 6 may be preliminarily divided into 5 subecoregions: (a) Macedonia-Thessalia (rivers Pinios-Thes, Aliakmon, Loudias and Axios), (b) Adriatic(Aoos), (c) Ionian (Kalamas, Acheron, Louros, Arachthos, Acheloos, Evinos, Mornos, Assopos, Krathis, Vouraikos, Pinios-Pel., Alfios, Pamissos), (d) Evrotas (Evrotas) and (e) Attiki-Beotia (Sperchios, Kifissos, Assopos). A chart of the proposed subecoregions and boundaries of subecoregions and fish districts are shown in Map 3 of Appendix 1. The streams of the Rhodes island have a distinctive fish fauna with no affinities to any of the established subecoregions and therefore should be placed in a separate subecoregion (not shown in the map). The established subecoregions have been corroborated to some extent by recent genetic studies of certain fish species, however more work needs to be done on DNA variation in certain fish to assist the definition of the historical drainage relationships in the Greek peninsula (Durand et. al. 1999). The proposed subecoregional delineation generally corroborates recent biogeographical proposals (see section 3.2.1.1). For example, shared absences of several species define a remarkable difference between the “Paleo-Hellas” and the “Ponto-Aegean” parts of ecoregions 6. The Attiko-Beotia and Ionian subecoregions appear to be quite distinct, since they are defined by a few similar species such as Rutilis ylikensis; however, both subecoregions share Pseudophoxinus stymphalicus. This and the few other common elements (e.g. R. ylikensis) suggest a past relationship among the drainages of the Ionian and Attiki-Beotia despite the distinctiveness of the fish assemblages as a whole. Note, however, that according to some authors, the R. ylikensis of the Ionian subecoregion may belong to a still undiscribed species (Economidis 1991). The remarkable diversity of the fish assemblages among basins in southern and western Greece and their relative species depauperation (many basins have less then 5 species) makes typological work in this region particularly challenging. Effectively, the established subecoregions are mostly determined by associations of fish species that largely owe their existence to geographic isolation and local speciation processes and not to current-date ecological barriers. Due to the complicated geological and past climatic history of the country, the number of “local” endemic species is large, which complicates the typology

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scheme. Despite the fact that some tolerant invasive species have distributions across subecoregions, each subecoregion is dominated by a group of endemic species. Despite broad similarities, larger rivers within subecoregions often have different fish faunas: the Sperchios and Kifissos rivers of subecoregion Attiki-Beotia, for example, show distinctive components, which necessitates to further subdivide this subecoregion into two freshwater fish districts (indicated in the map by the letters “a” and “b”). The faunal diversity within the Ionian subecoregion also necessitates further partitioning into smaller geographical divisions. We propose that the following fish districts in a tentative attempt to show this variation, while preventing the further division of the Ionian subecoregion: Ipiros, Acheloos and Messinian (indicated by the letters “a”, “b” and “c” respectively). Note that despite their separation by a marine area (Patraikos gulf), the rivers which comprise the Acheloos fish district have similar fish faunas. This similarity fits the geological evidence that before the present interglacial sea-level rise in the Patraikos Gulf the estuaries of the Acheloos river were located close to the estuaries of the Pinios and Alfios rivers and there may have been a confluence of two or more of these river systems before their exit to the sea. That some differences of the fish faunas of the three rivers exist can be explained by the presence of many lacustrine areas in the Acheloos river. Some uncertainty still exists about the Evrotas river, which we propose should be assigned to a separate subecoregional status, rather than to a fish district. The Evrotas river basin represents the geologically most ancestral part of the Greek peninsula and contains two, possibly three, unique endemic fish species. In addition to having a distinctive ichthyofauna, the Evrotas basin also exhibits other distinctive hydrogeologic and macroclimatic attributes. The proposed subecoregions and fish districts appear in Table 1 of Appendix 3. However, more units may emerge when fish and geological data from other parts of ecoregion 6 will be examined more thoroughly (e.g. this stands especially for the Thessalia-Macedonia subecoregion). In many cases, the geographic location of river mouths adequately describes crude zoogeographic units. This is broadly apparent when the western and the eastern parts of the Hellenic peninsula are compared (e.g. subecoregion Macedonia-Thessalia with subecoregion Ionian). For FAME, two “river regions” have been characterised for Greece, which are attributed to the marine bodies of the Hellenic Peninsula, the Aegean and Ionian. There seems to be some interest in maintaining the river region concept because especially in the west coast of Greece, rivers with an estuary on a common coast share biogeographical similarities. This is particularly true for the Ionian subecoregion. Although three rather distinct ‘freshwater fish districts’ have been identified there, these ‘districts’ share many species in common. In addition, some species in one district have ecologically equivalent species which are often closely related in the other districts. Finally, a problem already alluded to is the challenging issue of species status and other problems with taxonomic systematics. A few new species are yet to be described, yet some currently accepted ‘species’ may just represent natural clinal variation, and may someday be lumped with their closely related taxa. Ongoing genetic work and other biological investigations should clear-up the major problems within the next few decades; but, in the mean time we must critically assess the species status and usefulness of certain ‘species’ within a metrics scheme for ecological quality assessment. 3.3.2. Abiotic variables predicting communities Results of the reference site clustering analysis are presented in Tables 2-5 of Appendix 3 and Figs 7-10 of Appendix 2. The results were different when the locations were assessed by site or grouped per river or per abiotically-driven cluster group. The abiotically-driven cluster groups

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have fairly similar fish faunas and this may reflect species presence/absence from samples primarily due to sampling effort inconsistencies. Overall, abiotic parameters used for grouping clusters in this analysis failed to create clusters that had good relation to the species-driven cluster analysis of Greece’s major rivers. The five clusters created by the analysis of the calibrated reference sites showed differences due to local affects and a very poor regionalization (poor typological boundaries); therefore site abiotic typological work must be very carefully pursued only within similar ichthyological regions. The problem is that even within the proposed Ionian subecoregion from which most of our samples were taken there are at least three proposed fish districts! The analysis clearly identifies some problems with the available datasets. One type of problem concerns the calibrated reference sites. Some sites are poorly selected and not representative, others may have sampling effect problems, and other sites proved to be more impacted than the screening process may have shown, as mentioned above. Further analysis on this data set will not facilitate a better link between abiotic and biotic typologies. Other important problems include distinguishing the diversity of factors which affect the ichthyological community. Work on specifically identifying fish community types in biotically relevant within-river typological zones must continue. Southern and western Greece especially need further study to ensure current distributional data. Taxonomical revisions and/or rearrangements may reveal different relationships not yet in evidence and additional collections may clear-up distributional problems and biogeographical relationships. In a final effort to identify abiotic parameters predicting community types, the relationships between two biotic variables (species-richness and species abundance) and five abiotic variables were investigated (examples are shown in Appendix 2, Figs. 11-13). With few exceptions the relationships were weak or inconsistent. Despite the limitations of the available data, four parameters could be identified as potentially important in structuring fish communities: altitude, basin size, discharge, temperature. However, scarcity of appropriate fish data has prevented the statistical confirmation of these variables and the setting of biologically defensible boundaries. Because of the difficulties described above (few samples, non-representativeness, sampling problems), a sound biologically-based typology could not be established. On the basis of available data and employing quite a lot of expert judgment, we suggest that two parameters (and their boundaries) may prove important in predicting community types in a nationwide scale:

a) Basin size. The country is characterized by a fragmented hydrographic network with numerous small basins containing, in many cases, only one main river channel with permanent flow. Species richness, community composition and, to a lesser extent, abundance relate more to the entire basin size than to the river size. Hence, we have chosen to characterise the river catchment area in relation to the size of the entire drainage basin it belongs to, rather than in relation to the actual river catchment size. Three catchment classes were empirically established: small (<200 km2), medium (200-1000 km2) and large (>1000 km2). Small rivers account for the majority of cases. For example, of the more than 60 Peloponnesian entire rivers or streams, only six have basins exceeding 200 km2. b) Altitude. Altitude appears to be a key criterion in producing homogeneous zones, perhaps through its known broad relationship with temperature and other abiotic variables, e.g. slope. Altitude not only influences the distribution of many fish species, but it also determines (at least to a certain extent) the location of a site or a catchment area within the basin. Several biotic variables of river catchments, including richness, species composition and abundance,

12

are influenced by the location of the river within the basin, which is partly predicted by altitude.

A number of additional parameters are considered as important in structuring fish communities in particular areas, but the significance of these need validation. These are:

c) Discharge or other attributes of flow dynamics. Discharge and flow regime are important components of a river typology in the Mediterranean, but it is very difficult to assess and quantify these attributes without specialised fieldwork. Very scant data on reliable monthly discharge rates exist for most parts of most rivers and streams in Greece and the natural variability of flow regimes is in most cases very poorly studied if at all. d) Source type. This parameter is useful in or the purpose of reducing biological heterogeneity in rivers of western and southern Greece. For example, the spring-type Louros river maintains a stable flow throughout the year, which supports specialized habitats needed by species with narrow ecological requirements (this river harbours 16 species). The rain/snowmelt type Arachthos river has its estuary adjacent to the Louros on a common deltaic plain and is much larger in terms of basin area and annual discharge. The latter river harbours only eight species, and the reason is probably that the Arachthos river presents large seasonal discharge variations and does not sustain the same diversity of aquatic habitats which survive in the Louros. e) Presence of lakes and presence or size of floodplains. This parameter appears to be important at a local scale only. For example, one notable difference of the fish faunas of the Acheloos river, which communicates with three natural lakes, and the Alfios and Pinios rivers, which belong in the same subecoregion and once shared common estuaries with the Acheloos river, lies in the presence of many lacustrine species in parts of the Acheloos river. c) Other parameters. Empirical evidence justifies the choice of additional parameters, including temperature, precipitation and slope. In montane rivers for example, slope is of outstanding importance for depicting habitat variety and directly influences the fish communities; but the gradient slope is relatively difficult to measure accurately from 1:50 000 maps. Inclusion of these or additional abiotic parameters in a nationwide typology scheme may not be necessary for two reasons: (i) these criteria would complicate the typology scheme, enhancing substantially the number of river types, and (ii) most of these criteria can be predicted by combinations of other criteria, for example it has been shown in our PCA analysis that temperature correlates highly with altitude.

The influence of geology on fish communities remains unclear and may not be of prominent importance. Since geology is an obligatory environmental descriptor to be considered in typology schemes based on system A, effort should be devoted to establish links of geology with fish communities, direct or indirect (e.g. through effects on flow regime). An abiotic classification of the FAME sites (based also on geology and the two other obligatory factors of system A of the WFD - altitude and catchment size) appears in Appendix 2, Fig. 14 3.3.3. Problems associated with developing river typology The high degree of endemism coupled with the short-range species’ distributions have generated the need for a high level of subecoregional and other biogeographical discrimination. Although useful in reducing the biological heterogeneity of the ecoregions, this regionalization requires us to organise monitoring goals and objectives in small spatial frameworks. High hydrological

13

fragmentation (many small rivers) and substantial amount of environmental heterogeneity further complicates typology, generating the need to set reference conditions in a large number of strata. Available data do not allow to confirm that the established types are associated with distinguishable fish communities and to define biologically relevant ranges of abiotic factors. 3.3.4. A preliminary typology scheme for the Peloponnese An attempt was made to create for FAME a biologically meaningful typology for the Peloponnesian part of the Ionian subecoregion (Acheloos and Messinian Freshwater Fish Districts), which was the most well-explored area during our investigations. Combinations of catchment area and altitude initially seem to crudely describe the distribution and abundance of characteristic or dominant species. For large rivers, discharge level may be added as an additional criterion. The role of groundwater in the maintenance of flow seems to be important, however, due to the predominance of calcareous formations (accounting for karstic phenomena), there seems to be no need to use source type (or geology) as a zonation criterion. The importance of slope and precipitation for partitioning variability within the subecoregion needs to be tested (e.g. by examining to which extent these parameters can be surrogated by combinations of altitude, catchment size and discharge). Nine river types were established in this preliminary biotic typology classification using catchment and altitude characteristics (ten types, if two discharge classes will be added) (Appendix 3, Table 6). In the absence of suitable biotic data, the boundaries for the selected variables were placed either using expert judgement or guidance provided by the WFD. Map 4 of Appendix 1 shows how this preliminary river type classification would apply in the FAME rivers of the Peloponnese part of the Ionian subecoregion. The proposed typology should be regarded as provisional and it is in large part hypothetical (but not arbitrary); itneeds to be verified and modified from the biocoenotic point of view when adequate data become available. 3.4. Initial thoughts on metric selection - setting reference conditions to metrics Candidate metrics were selected on the basis of knowledge of fish fauna and of the aquatic systems of Greece, and the theoretical expectations for each metric was delineated, during WP3. The selection of metrics takes into account the prevailing anthropogenic pressures and degradation types (water abstraction, discharge variations due to dam operation, fragmentation, reclamation and river management works, pollution). A general difficulty for establishing metrics for development of IBI applications in small rivers is that species richness is low (hence, few metrics expressing the structure of the community are available). Moreover, the fish communities in these rivers are dominated by tolerant species with wide ecological requirements (hence, few metrics expressing the function of the ecosystem are available). Difficulty also arises from the incomplete biological and ecological knowledge of the species requirements (needed to define guilds, habitat specialization or tolerance levels) in areas not adequately covered by previous investigations. However, the applicability of traditional multimetric assessment methods that use a large number of metrics describing a broad range of structural and functional attributes of the fish communities is questionable in the case of rivers with depauperate fish faunas, because they may change the scales of impact and thus mask very important metrics. By adding a metric that is not biologically relevant or sensitive to the prevailing pressures in order to reach a pre-assumed number of metrics less weight is given to more relevant metrics. We suggest that appropriate methods for low species richness rivers should be based on a limited number of metrics. For example, in the case of flow regime disturbances the methods could include metrics for total fish abundance and

14

biomass, the abundance or proportion of sensitive species to flow reduction, and life-history parameters, such as longevity or proportion of large age (size) groups which seem to be intolerant to reduced flow. With the data available at this time it is not possible to describe reference conditions using spatial methods in any subecoregion. Problems encountered include:

• Few reference sites available (in conjunction with highly disjointed typologies that increases the number of reference sites required)

• Sites were not selected to be representative of rivers or river sections and do not express the ranges of natural variability

• High inter and intra annual variability of ecological conditions reflects to high biological variability, which increases the number of reference sites required to assess the ranges variability in metric values

• Incomplete or untested biotic typology scheme • Poor quality data in some cases due to unstandardised sampling methodologies

Conclusion Combinations of abiotic variables such as catchment area, altitude, temperature, gradient slope, water source type and perhaps several abiotic instream habitat variables seem to be able to describe the distribution and abundance of characteristic or dominant fish species in Greek rivers, but a large dataset is needed to create a longitudinal biotic zonation, and build a biotically-based typology and reference conditions. Our analysis has begun this work for Greece by suggesting a ichthyological regionalization at the sub-ecoregion scale, and beginning the first typology-centered spatially-based analysis on the currently best available electrofishing sampling dataset we have access to. This dataset proved inadequate to define significant biotic typologies, but it has guided us through the process and the methods of using fish as indicators in order to develop a biologically-based multimetric index for ecological assessment. The work so far shows that the “fish quality element” does work to integrate many environmental pressures with a broad ecological basis: fish communities in Greece are certainly affected by anthropogenic changes which alter or degrade the ecosystem ranging from the basin scale down to even the river segment scale. More fieldwork is urgently needed in order to continue this analysis and to develop a pilot multimetric index for validation. Assessment protocols must be developed which can distinguish between the variation in environmental conditions that occur naturally and the variation caused by human impact. Fish-based research on this spatially-based approach should provide an impetus for assessing larger “basin-scale pressures” for the rivers of Greece. The fish-based assessment approach does provide an important tool with a broad ecological basis. This fish-based assessment tool should catalyse progress for the development of a much-needed practical approach to type-specific reference condition development which is critical in order to use fish bioindicators for assessment. Our initial analysis shows that these assessment tools are possible to develop in Greece if sampling is conducted in a systematic and standardized way, despite the country’s remarkable environmental heterogeneity. References Angermeier, P., Smoger, R.A., & Stauffer, J.R. (2000). Regional frameworks and candidate

metrics for assessing biotic integrity in mid-atlantic highland streams. Trans. Amer. Fisheries Society, 129: 962-981.

15

Bianco, P.G. (1990). Potential role of the palaeohistory of the Mediterranean and Paratethys basins on the early dispersal of Euro-Mediterranean freshwater fishes. Ichthyol. Explor. Freshwaters, 1(2): 167-184.

Bobori, D.C. & Economidis P.S. (MS in Prep.). Fish biodiversity in the main Greek rivers and lakes. 33 p.

Durand, J.D., Templeton, A.R., Guinand, B., Ismaridou, A. & Y. Bouvet. (1999). Nested clade and phylogeographical analyses of the chub, Leuciscus cephalus (Teleostei, Cyprinidae), in Greece: Implications for Balkan Peninsula biogeography. Molecular Phylogenetics and Evolution, 13(3):566-580.

Economidis, P.S. & Banarescu P.M. (1991). The distribution and origins of freshwater fishes in the Balkan Peninsula, especially in Greece. Int. Revue ges. Hydrobiol. 76 (2): 257-283.

Economou, A.N. and collaborators (1999). Threatened freshwater fishes of western Greece and Peloponnese - Distribution, abundance, threats and conservation measures. Technical Report, National Centre for Marine Research, Institute of Inland Waters. 341 pp. Plus 4 Append. (In Greek)

Economou, A.N. and collaborators (2001). Fisheries management and rational exploitation of the freshwater water resources of Greece: Prefectures Aetoloakarnania, Eurytania, Karditsa, Boetia, Arkadia, Ilia & Achaia. Technical Report, National Centre for Marine Research, Institute of Inland Waters. 599 pp. April 2001. (In Greek)

EKBY - Greek Wetland-Biotope Center (1994). Inventory of Greek Wetlands as Natural Resources. Greek Wetland-Biotope Center – Goulandris Museum of Natural History, 587 pp.

Gretes, W.C. & Maurakis, E.G. (2001). Longitudinal distributions of fishes in river drainages of Greece, with comments on assessing fish biodiversity in the southern Balkan peninsula. Bios, 6: 91-108.

Maurakis, E.G., Pritchard, M.K. & Economidis, P. S. (2001). Historical relationships of mainland river drainages in Greece. Bios, 6:106-124.

Maurakis, E.G. & Economidis, P.S. (2001). Reconstructing biogeographical relationtionships of river drainages in Peloponessos, Greece using distributions of Freshwater Cyprinid fishes. Bios, 6:125-132.

Skoulikidis, N.T., Bertahas, I. & Koussouris, T. (1998) The environmental state of freshwater resources in Greece (rivers and lakes). Environmental Geology 36(1-2):1-17.

Wallin, M., Wiederholm, T. & Johnson, R. (2002). Guidance on establishing reference conditions and ecological status class boundaries for inland surface waters. CIS Working Group 2.3. – REFCOND. Version 3.

16

APPENDIX 1: MAPS Map 1. The Hellenic Western Balkans ecoregion. The portion in yellow shows the areas covered

by the investigations carried out by the NCMR.

17

Map 2. Sampling stations (in yellow), stations included in the FAME database (in green) and

stations characterised as reference (in red).

18

Map. 3. Proposed subecoregions and freshwater fish districts within the areas of Hellenic

Western Balkans (Ecoregion 6).

19

Map 4. Schematic representation of the provisional typology of the FAME rivers in the Peloponnese part of the Ionian subecoregion (boundaries defined in Table 6 of Appendix 3).

20

APPENDIX 2: FIGURES

Fig. 1. Histograms showing the distribution of impact classes for five priority pressure categories; derived from the interrogation of the Greek FIDES database (N=56 sites).

Connectivity River

0

5

10

15

20

25

30

35

1 2 3 4 5

impact score

No

of s

ites

Connectivity Segment

010203040

1 2 3 4 5

impact score

No

of s

ites

Hydrological regime

0

2

4

6

8

10

12

14

16

1 2 3 4 5

impact score

No

of s

ites

Morphological condition

05

10152025

1 2 3 4 5

impact score

No

of s

ites

Average score

05

10152025303540

1 2 3 4 5

impact score

No

of s

ites

Nutrients organic input

0

5

10

15

20

25

30

35

1 2 3 4 5

impact score

No

of s

ites

21

Fig. 2. Sorenson Group average cluster analysis of major Greek rivers in ecoregion 6. In

this figure TWINSPAN Classification (see Fig. 3) has been superimposed in colour. Distance (Objective Function) .000 .488 .976 1.464 1.953 |-------+-------+-------+-------+-------+-------+-------+-------+ Information remaining (%) 100.000 75.000 50.000 25.000 .000 |-------+-------+-------+-------+-------+-------+-------+-------+ EVROTAS --------------------------------------| | PAMISOS | | | | PERISTER | | |-| | VELIKAS | | | | |----------| | KARYA | | | | | | | NEDA --| | | | | ALFIOS | | | | | |----------| KALAMAS || | | | || |-----| | | MORNOS || | | | | | | | | | PINIOS-P -|--| | | | | | | | | | | EVINOS -| |-| | | | | | | | | | | ACHERON ----| |-| | |-------| | | | | | | | | | ACHELOOS ------| |----| | | | |-------------| | | | | | | ARACHOS ---| | | | | | | |----| | |----------| | | LOUROS ---| | | | | | | | | SPERXIOS -------------------| | | | | | | AOOS ---------------------------| | | | | PINIOS-TH | | | |------------------------------------------------| | ALIAKMON | | | | LOUDIAS | | | | AXIOS | | |

KIFISSOS-----------------------------------------------------------------|

22

Fig. 3. Dendrogram according to TWINSPAN analysis between the 22 major rivers and 59 fish

species (see Fig. 5 for original data).

Dendrogram of riverine sites according to the TWINSPAN analysis (22 sites x 59 fish species)

Pinios-Pelop, Acheloos Alfi.,Morn.,Evin.,Ache.,Kala.,Arac.,Lour.

9 Evro.,Pami.,Veli.,Kary.,Peri.,Neda

15 Kifissos,Sperchios

17

Pini-Thes,Alia.,Axio.,Loud. Aoos

5

Fig 4. Fish species per clustered site according to the TWINSPAN analysis (see Fig 5). Numbers

denote species names, as in Fig. 5. Fish species per clustered site

15,18,45,49,52,55Pinios-Pelop, Acheloos

5,14,19,21,27,31,34,57,39Alfi.,Morn.,Evin.,Ache.,Kala.,Arac.,Lour.

56,40,38,30Evrotas

48,47,29,10,8,22,56,40,38,30Evro.,Pami.,Veli.,Kary.,Peri.,Neda

37,39,44,51Kifissos,Sperchios

1,7,2,3,6,9,12,16,17,20,24,25,26,28,32,35,36,41,42,43,46,50,53,54,58,59Pini-Thes. Alia.,Axio.,Loud.

4,11,13,33,23Aoos

23

FIG. 5. Two-way ordered table according to TWINSPAN analysis between 22 major rivers and 59 native freshwater fish species as simplified in Fig 4.

12221 1 11111 1 1 9012681790452323458167 33 Pach pic ----1----------------- 1111 13 Cob sp ----1----------------- 1111 11 Chon nas ----1----------------- 1111 4 Barb pin ----1----------------- 1111 23 Gob gob 11111----------------- 1110 59 Zig bal ---1------------------ 110 58 Vimb mel 1111------------------ 110 54 Tinc tin 1111------------------ 110 53 Sil gla 1111------------------ 110 50 Scar ery --11------------------ 110 46 Sab bal 1-11------------------ 110 43 Rut rut 1111------------------ 110 42 Rhod ama 1111------------------ 110 41 Pun pla --11------------------ 110 36 Phox pho --11------------------ 110 35 Perc flu 1111------------------ 110 32 Pach mac 1111------------------ 110 28 Knip the 1--------------------- 110 26 Knip cau -111------------------ 110 25 Gob eli 1111------------------ 110 24 Gob ban 1111------------------ 110 20 Esox luc 1111------------------ 110 17 Cyp car 1111------------------ 110 16 Cob var 1111------------------ 110 12 Chon var 1111------------------ 110 9 Barb mac 1111------------------ 110 6 Barb bar 1--------------------- 110 3 Barb bal ---1------------------ 110 2 Alb alb 1111------------------ 110 7 Barb cyc 1--1--------------1--- 10 1 Alb bip 11111-------------1--- 10 22 Gast acu 1111------1--11---1--- 01 8 Barb gra ------------------1--1 0011 48 Salm tru -1-11-1111-111----1--- 0010 47 Sal flu 1111-1111111-11--1111- 0010 29 Leuc cep 1111111111111111111-1- 0010 10 Barb pel -11111111111111111--1- 0010 51 Scar gra ---------------------1 00011 44 Rut yli ---------------------1 00011 37 Pse beo ---------------------1 00011 56 Trop spa --------------1111-11- 00010 40 Pun hel ------------------1--- 00010 38 Pse lac -------------------1-- 00010 30 Leuc kea -------------------1-- 00010 39 Pse sty -----1111-111111111--1 00001 55 Trop hel -----11--------------- 000001 52 Sil ari ------1--------------- 000001 49 Scar aca ------1--------------- 000001 45 Rut sp1 ------1--------------- 000001 18 Econ tri ------1--------------- 000001 15 Cob tri ------1--------------- 000001 57 Val let -----1111-11-1-------- 000000 34 Para epi ----------1--1-------- 000000 31 Leuc ple -----111-11111-------- 000000 27 Knip sp1 -----1111111---------- 000000 21 Eud hel -------------1-------- 000000 19 Econ pyg ------1----111-------- 000000 14 Cob hel ------------11-------- 000000 5 Barb alb -----11-11-111-------- 000000

0000011111111111111111 0000100000000000000001 0000000000000011 00000000011111 00111111100001 0000011

24

Fig. 6. Sorenson cluster analysis: Sorensen distance, group average of native fish species in Greece’s Ecoregion 6. TWINSPAN groupings have been partially superimposed on this analysis to show the most distinctive groupings (See Fig.3). Distance (Objective Function) .000 1.113 2.226 3.340 4.453 |-------+-------+-------+-------+-------+-------+-------+-------+ Information remaining (%) 100.000 75.000 50.000 25.000 .000 |-------+-------+-------+-------+-------+-------+-------+-------+ Alb bip | Gob gob | Alb alb | Barb mac | Chon var | Cob var | Cyp car | Esox luc | Gob ban |-----| Gob eli | | Pach mac | | Perc flu | | Rhod ama | | Rut rut | |--| Sil gla | | | Tinc tin | | | Vimb mel | | |-| Knip cau | | | | Sab bal | | | | Gast acu ------| | |--------| Barb cyc ---------| | | Barb bal |-| | | Zig bal | |--------| |---------------------| Phox pho | | | | Pun pla |-| | | Scar ery | | | Barb bar |-------------------| | Knip the | | Barb alb | | Leuc ple |-------| | Knip sp1 | | | Val let | | |-----| Barb pel | |---------------| | | Leuc cep || | | | | Sal flu ||-----|| | | | Pse sty -| || |----| | | Salm tru -------| | | | | Cob hel ---|---------| | | | | Econ pyg ---| |----------| | | | Eud hel -----|-------| | | | Para epi -----| |------------| |------| Cob tri | | | | Econ tri | | | | Rut sp1 | | | | Scar aca |---| | | | Sil ari | |------------------------| | | Trop hel ----| | |-------|

Barb pin | | | | Chon nas | | | | Cob sp |-----------------------------------------------| | | Pach pic | | | Barb gra --| | | Pse beo | |--------------------------------| | | Rut yli |-| |-------------------| | Scar gra | | |

Pun hel -----------------------------------| | Leuc kea |----------------| | Pse lac* | |--------------------------------------------| Trop spa -----------------| *Pseudophoxinus laconicus is a recently described taxon, related to Pseudophoxinus stymphalicus.

I

25

Fig. 7. Arrangement of riverine sites and environmental variables according to the PCA ordination. Arrows show the strength of the variables and numbers indicate the grouping of the sites according to the cluster analysis. Sites close to a particular arrow indicate a great influence of the corresponding variable.

Fig. 8. Dendrogram of sites based on Ward’s clustering and Euclidean distance of proximity.

Five groups are distinct: Group 1: 1 2 3 4 5 6 7 8 21 28 Group 2: 9 11 15 18 20 32 Group 3: 10 12 13 19 22 Group 4: 14 16 17 29 30 31 Group 5: 23 24 25 26 27

32151811209 2213121910212825648371 313029171614 2726252324

-298,27

-165,52

-32,76

100,00

Similarity

Observations

26

Fig 9. Box plots of abiotic variables in the group samples. Boxes represent interquartiles, solid lines the individual sites per cluster and horizontal lines the variable medians. Boxes that do not overlap show significant differences between clusters. Basin size – cluster 1 Temperature – cluster 5, Gradient slope – 2, Altitude- 5, Discharge class (in log values)- 4.

54321

7000

6000

5000

4000

3000

2000

1000

0

Clusters

Bas

in s

ize

54321

18

13

8

Clusters

Tem

pera

ture

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Clusters

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dien

t slo

pe

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1000

500

0

Clusters

Alti

tude

54321

2

1

0

Clusters

Dis

char

ge c

lass

(log

val

ues)

27

Fig. 10. Classification tree analysis of site samples in terms of exclusive importance. Group 5

distinguishes from the others because it shows mean altitude >865m. Next, Group 1 with mean basin size >2394m2 , next group 2 with a gradient slope >15.7 metric units, Group 4 with a discharge class ranging between 10 and 100 and finally Group 3 indicating the lowest class 1.

Classification Tree for Reference sitesNumber of splits = 4; Number of terminal nodes = 5

Altitude<=865

Basin size<=2394

Grad slope<=15,7

Disch class= 1

26 6

17 9

11 6

5 6

1

1 5

2 1

4 2

3 4

12345

28

Fig. 11. Species richness vs. total basin area. Medium and small Fame database rivers in southern

Greece and their species richness (based on historic records). Species richness varies remarkably in the small rivers (under 200 sq. Km) for a variety of habitat-related and biogeographical reasons. (Data from NCMR Database)

0

2

4

6

8

10

12

14

16

0 200 400 600 800 1000

Total Basin Size

Tota

l Spe

cies

Num

ber

Fig. 12. Biomass vs Altitude. A negative relationship is only just discernable, although very few

high elevation sites are shown in the scatter graph (Fides site data n=22 sites where biomass was calculated).

0,00

20,00

40,00

60,00

80,00

100,00

120,00

140,00

160,00

180,00

0 200 400 600 800

Altitude (m.)

Bio

mas

s (K

g/H

a)

29

Fig. 13. Total abundance vs gradient slope. There is only a slight negative relationship shown

when total fish abundance is plotted against recorded slope at each site. This result is probably an artifact of slope recording from 1:50000 scale topographic maps not at the site. The relationship is thought to be strongly negative in reality. FAME SITE DATA (n=56 sites, all FIDES sites included).

0

5000

10000

15000

20000

25000

30000

0 5 10 15 20 25 30

Slope

Abu

ndan

ce (I

nd/H

a)

30

Fig. 14. Distribution of FAME sites following the designations of WFD’s System A (class boundaries as provided by the WFD).

ALTITUDE

CATCHMENT SIZE

GEOLOGY

Number of sitesNumber of refer

Low

Small Med

C 6

(2)

S (0)

S (0)

Large

C 10 (4)

S (0)

Mid

Small Med Large Very Large

C 1

(1)

S (0)

C 3

(3)

S (0)

S (0)

S 3

(3)

C (0)

High

Small(0)

Med(0)

Large

C 7

(6)

S (0)

31

APPENDIX 3: TABLES

Table 1. Comparison of biogeographic regions and proposed subecoregions. Freshwater Fish Biogeographic Divisions (Subdivisions)

Proposed Fish Subecoregions

Freshwater fish districts

Main river basins included

Paleo-Hellas (Adriatic) Adriatic - Aoos

Epirus Kalamas, Acheron, Louros, Arachthos

Paleo-Hellas (Ionian)

Acheloos

Acheloos, Mornos, Vouraikos, Krathis, Sythas, Asopos, Pinios, Alfios

Ionian

Messinian Neda, Pamissos, Yiannouzagas, Filiatrino, Karya, Velikas Paleo-Hellas (Peloponnesian)

Evrotas - Evrotas

Kifissos Kifissos Paleo-Hellas (Attiki-Beotia) Attiki-Beotia

Sperchios Sperchios Ponto-Aegean (Macedonia-Thessaly)

Macedonia-Thessalia - Pinius, Aliakmon,

Loudias, Axios Table 2. Factor loadings (correlation coefficients) between abiotic parameters and the 4

principal component axes. The first two axes explain 71,1% of the total variation. Altitude and air temperature (Temp), in reverse correlation sign, are responsible for the formation of axis 1. Discharge class (Disch cl), gradient slope(Grad slo) and basin size(Basin Si) are the most influential variables for the second axis correlation coefficients not exceeding 0.700. The river basin size is still informative for the formation of the third axis explaining a 16.2% further variation and the gradient slope for the formation of the 4th axis (11.7%).

Factor Loadings and Communalities Variable Factor1 Factor2 Factor3 Factor4 Communality Disch cl -0,351 -0,677 -0,491 0,422 1,000 Grad slo -0,473 0,645 0,239 0,550 1,000 Altitude 0,957 0,099 -0,060 0,210 0,973 Temp -0,945 -0,140 0,177 -0,175 0,974 Basin Si 0,239 -0,661 0,689 0,173 1,000 Variance 2,2125 1,3404 0,8081 0,5857 4,9467 % Var 0,443 0,268 0,162 0,117 0,989

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Table 3. Abiotic clustering of sites based on the interrogation of Fides database. Data used in the cluster analysis are the calibrated reference sites in the Ionian River Region (n=32 sites) (Subecoregions Ionian, Adriatic and Evrotas). CLUSTER GROUP 1=BLACK, GROUP 2= BLUE, GROUP 3 = GREEN, GROUP 4=RED, GROUP 5=PINK.

Assigned number of site (See Fig.8)

River_name Site_name Site_code WFD Syst A

Code (See Table AA)

Subeco- region

(Fish districts given in Brackets, see Map)

1. Alfios Psathion GR01110002 MLC Ionian (B) 2. Alfios Kato Asea GR01110007 MLC Ionian (B) 3. Lousios Prodromos GR01110014 MLC Ionian (B)

4. Lestenitsas (Enipeas) Alfiou Varvasena GR01110016 LLC Ionian(B)

5. Ladonas Spilia GR01120012 MLC Ionian(B) 6. Ladonas Loutra Ireas GR01120013 LLC Ionian (B) 7. Aroanios Krinophyta GR01120015 MLC Ionian(B) 8. Erymanthos Tripotama GR01130009 MLC Ionian (B) 9. Neda Kakaletri GR01600019 MMC Ionian (C) 10. Velikas Strefi GR01610113 LMC Ionian (C) 11. Nedon Nedousa GR01630027 MSC Ionian (C) 12. Peristeras Kalo Nero GR01990021 LMC Ionian (C) 13. Yiannouzagas Schinolaka GR01990115 LSC Ionian (C) 14. Ladonas Piniou Agios Nikolaos GR02100033 LMC Ionian (B) 15. Vouraikos Diakopto GR02630040 LMC Ionian (B) 16. Sythas Riza GR02680045 LMC Ionian (B) 17. Krathis Tsivlos GR02690042 MMC Ionian (B) 18. Evrotas Oinous GR03100056 MLC Evrotas 19. Paroritis Parori GR03100123 MLC Evrotas 20. Piges Kandylas Sintzi GR03670060 MMC Ionian (B) 21. Myrtia Myrtia GR04140074 MLC Ionian (B) 22. Hiliadou Hiliadou GR04300080 LMC Ionian (B) 23. Aoos Aoos-b GR05120130 HLC Adriatic 24. Aoos Aoos-c GR05120131 HLC Adriatic 25. Aoos Aoos-d GR05120132 HLC Adriatic 26. Aoos Aoos-e GR05120133 HLC Adriatic 27. Aoos Aoos-f GR05120134 HLC Adriatic 28. Arachthos Ano Arachthos GR05210087 HLC Ionian (A) 29. Metsovitis Arachthos Trophodotisi Aoou GR05240088 MLC Ionian (A) 30. Kalamas Soulopoulo GR05300092 LLC Ionian (A) 31. Louros Agios Georgios GR05400095 LMC Ionian (A) 32. Louros Kouklesi GR05400097 LMC Ionian (A)

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Table 4. Fish species occurrence per cluster group in the Ionian River Region (some distinctive species have been highlighted).

Fish species

Group 1 Group 2 Group 3 Group 4 Group 5 Angu ang Ang ang Ang ang Barb alb Albu bip Barb alb Barb pel Barb pel Barb pel Barb pel Barb pel Leuc cep Knip sp Gast acu Leuc cep Leuc cep Leuc cep Leuc ple Pseu sty Leuc ple Pseu sty Sala flu Leuc sva Salm tru Trop spa Pseu sty Sala flu Trop hel Table 5. Analysis of Variance for Richness and density (N/ha Log) (no statistically

significant results). Factor Type Levels Values Ward 5 fixed 5 1 2 3 4 5 Analysis of Variance for N/ha LOG, using Adjusted SS for Tests Source DF Seq SS Adj SS Adj MS F P Ward 5 4 2,582 2,582 0,645 0,27 0,898 Error 27 65,665 65,665 2,432 Total 31 68,247 Analysis of Variance for Richness, using Adjusted SS for Tests Source DF Seq SS Adj SS Adj MS F P Ward 5 4 12,435 12,435 3,109 0,99 0,428 Error 27 84,533 84,533 3,131 Total 31 96,969

34

Table 6. A preliminary typology scheme for the Peloponese part of the Ionian subecoregion. The characteristic fish species in each type are shown, with the dominant species highlighted, due to different habitat and abiotic characteristics species dominance may vary even in reference conditions.

Type

Fish species (dominant species are highlighted)

Total number of species per type > 1 %

Variables (catchment /

altitude)

Comments

1 Salmo trutta, B. peloponnesius 2-4 Large-size /

High-altitude

One rather variable biotic type Fish are absent in many reaches due to natural obstacles.

2

, Leuciscus pleurobipunctatus, B. peloponnesius, Leuciscus cephalus Pseudophoxinus stymphalicus

3-6 Large-size / Mid-altitude

Perhaps two or three subtypes present

3 L. cephalus, B. peloponnesius, P. stymphalicus, L. pleurobipunctatus, Salaria fluviatilis, Mugillidae,

High discharge: 7-9 Low discharge: <4

Large-size / Low-altitude

Perhaps two types present, this may have great ranges of biological attributes.

4 B. peloponnesius 1 Mid-size / High-altitude

Fish may be absent due to natural obstacles.

5 L. cephalus, B. peloponnesius, P. stymphalicus

2-4 Mid-size / Mid-altitude

May have high range of biological attributes.

6 L. cephalus, B. peloponnesius, Anguilla anguilla, Mugillidae, 5-8 Mid-size / Low-

altitude

May have high range of biological attributes.

7 B. peloponnesius 0 –1 Small-size / High-altitude

Fish may be absent due to natural obstacles.

8 L. cephalus, B. peloponnesius 1-2 Small-size / Mid-altitude

May be variable based on geography and river history.

9 L. cephalus, , Tropidophoxinellus spartiaticus, B. peloponnesius

2-4 Small-size – Low-altitude

May have a high range of biological attributes.

Catchment classes: small (<200 km2), medium (200-1000 km2) and large (>1000 km2) Altitude classes: low (<200 m), medium (200-800) and high (>800 m). Discharge classes: low (<10 m3/sec), high (> 10 m3/sec)

35