Drosos Koutsoubas

Setting Priorities for Regional Conservation Planning in the Mediterranean Sea

Spatial prioritization in conservation is required to direct limited resources to where actions are most urgently needed and most likely to produce effective conservation outcomes. In an effort to advance the protection of a highly threatened hotspot of marine biodiversity, the Mediterranean Sea, multiple spatial conservation plans have been developed in recent years. Here, we review and integrate these different plans with the goal of identifying priority conservation areas that represent the current consensus among the different initiatives. A review of six existing and twelve proposed conservation initiatives highlights gaps in conservation and management planning, particularly within the southern and eastern regions of the Mediterranean and for offshore and deep sea habitats. The eighteen initiatives vary substantially in their extent (covering 0.1–58.5% of the Mediterranean Sea) and in the location of additional proposed conservation and management areas. Differences in the criteria, approaches and data used explain such variation. Despite the diversity among proposals, our analyses identified ten areas, encompassing 10% of the Mediterranean Sea, that are consistently identified among the existing proposals, with an additional 10% selected by at least five proposals. These areas represent top priorities for immediate conservation action. Despite the plethora of initiatives, major challenges face Mediterranean biodiversity and conservation. These include the need for spatial prioritization within a comprehensive framework for regional conservation planning, the acquisition of additional information from data-poor areas, species or habitats, and addressing the challenges of establishing transboundary governance and collaboration in socially, culturally and politically complex conditions. Collective prioritised action, not new conservation plans, is needed for the north, western, and high seas of the Mediterranean, while developing initial information-based plans for the south and eastern Mediterranean is an urgent requirement for true regional conservation planning.

Macrobenthic community structure over the continental margin of Crete (South Aegean Sea, NE Mediterranean)

Macrobenthic faunal composition, abundance, biomass and diversity together with a suite of sedimentary environmental parameters were investigated on a seasonal basis in order to determine factors regulating faunal distribution over the oligotrophic continental margin of the island of Crete (South Aegean Sea, North Eastern Mediterranean). Macrofaunal species composition was similar to that of the western Mediterranean and the neighboring Atlantic having several common dominant species. Mean benthic biomass, abundance and diversity decreased with depth, with a major transition zone occurring at 540 m, beyond which values declined sharply. At comparable depths biomass and abundance values were considerably lower to those found in the Atlantic, high-lighting the extreme oligotrophy of the area. The continental margin of Crete was characterised by a high diversity upper continental shelf environment (dominated by surface deposit feeding polychaetes) and a very low diversity slope and deep-basin environment (dominated by carnivorous and filter feeding polychaetes). Classification and ordination analyses revealed the existence of four principle clusters divided by a faunal boundary between 200 and 540 m, as well as beyond 940 m depth. Significant correlations between macrofauna and sediment parameters led to the conclusion that besides depth, food availability (as manifested by the concentration of chloroplastic pigments) is the principle regulating factor in the system. Such being the case, the prevailing hydrographic features that structure the pelagic food web and are directly responsible for the propagation of organic matter to the benthos also affect its community structure.

Deep sea molluscan fauna of the Cretan Sea (Eastern Mediterranean): Faunal, ecological and zoogeographical remarks

The deep sea molluscan fauna of the Cretan Sea (Eastern Mediterranean) was investigated from living material collected by the R/Vs“AEGAEO” and“PHILIA” cruises in the framework of the MTP/MAST EU research programme CINCS, carried out by the I.M.B.C. Examination of the deep sea benthos, with particular reference to the phylum Mollusca, over a grid of stations from depths between 40 and 1570 m, revealed the presence in the area of a diverse fauna consisting of 147 species belonging to 6 different classes. Large numbers of species (44) are new elements of the molluscan fauna of the Cretan Sea while another 4 species (1 Polyplacophora, 2 Gastropoda, and 1 Bivalvia) have not been reported so far from the Aegean or the Eastern Mediterranean. The majority of the species exhibit a wide bathymétrie distribution, from the continental shelf region to the bathyal slope, and only a few species are considered as deep sea species (reported only from the latter). The faunal composition of the collected material from the studied area (in depths over 200 m) clearly demonstrates the presence in the Cretan Sea of theAbra longicallus-association, already reported in other deep basins of the Mediterranean where similar research has been carried out. However, the presence of the bivalveNuculoma aegeensis even in the shallow waters of the continental shelf strengthens the opinion of other authors (Janssen 1989;Dounas &Koukouras 1992) that theNuculoma aegeensis “facies” of the above association is not found as deep asdi Geronimo (1974) had claimed (1500 m). Most of the deep sea mollusc species collected from the Cretan Sea are distributed from the Mediterranean to the Atlanto-Mediterranean and Boreal province while no species with an Indo-Pacific origin (Lessepsian immigrants) were found. Taking into consideration results of studies on the molluscan fauna from shallow waters of the Cretan Sea (Koutsoubas et al. 1992) it can be concluded that this part of the Mediterranean could not be considered as an impoverished system, as it hosts a rather enriched and diverse molluscan fauna numbering more than 400 species.KurzfassungDie Tiefwasser-Mollusken-Fauna aus dem Kretischen Meer (östliches Mittelmeer) wurde anhand von lebendem Material ausgewertet, das während der R/Vs“AEGAEO” und“PHILIA” Fahrten gesammelt wurde, und zwar im Rahmen des MTP/MAST EU Forschungsprojektes CINCS, durchgeführt vom I.M.B.C. Die Untersuchung des Tiefwasser-Benthos, mit besonderem Schwerpunkt auf dem Stamm der Mollusken, zeigte entlang einer Reihe von Stationen, im Tiefenbereich zwischen 40 und 1570 m, die Anwesenheit einer mannigfaltigen Fauna, bestehend aus 147 Arten, die zu 6 verschiedenen Klassen gehören. Eine bedeutende Anzahl von Arten (44) stellt im Kretischen Meer neue Elemente der Mollusken-Fauna dar, während 4 weitere Arten (1 Polyplacophora, 2 Gastropoda, und 1 Bivalvia) noch nicht vom Agäischen oder östlichen Mittelmeer gemeldet worden sind. Die Mehrheit der Arten zeigte eine breite bathymetrische Verteilung vom Kontinentalschelf bis zum bathyalen Abhang, und nur wenige zählen zu den Tiefwasserformen (gemeldet im bathyalen Abhang). Die faunistische Zusammensetzung des gesammelten Materials in der untersuchten Region (in Tiefen über 200 m) demonstriert deutlich das Vorhandensein derAbra longicallus-Assoziation im Kretischen Meer, wie sie schon bei ähnlichen Untersuchungen in anderen Tiefseebecken des Mittelmeeres beschrieben worden ist. Die Präsenz jedoch der bivalvenNuculoma aegeensis, sogar in den flachen Gewässern des Kontinentalschelfs, bekräftigt die Meinung anderer Autoren (Janssen 1989;Dounas &Koukouras 1992), daß dieNuculoma aegeensis “Fazies” der oberen Assoziation nicht so tief gefunden werden wiedi Geronimo (1974) behauptet hat (1500 m). Die meisten Tiefwasser-Mollusken-Arten, die im Kretischen Meer gesammelt wurden, sind von der Mediterranen bis zur Atlanto-Mediterranen und der borealen Provinz verbreitet, während keine Arten Indo-Pazifischen Ursprungs (Lessepsian immigrants) gefunden wurden. Unter Berücksichtigung der Ergebnisse von Studien über die Mollusken-Fauna der flachen Gewässer des Kretischen Meeres (Koutsoubas et al. 1992), könnte man daraufschließen, daß das Kretische Meer, eine eher reiche und mannigfaltige Mollusken-Fauna mit mehr als 400 Arten beherbergt.

Five key attributes can increase marine protected areas performance for small-scale fisheries management

Marine protected areas (MPAs) have largely proven to be effective tools for conserving marine ecosystem, while socio-economic benefits generated by MPAs to fisheries are still under debate. Many MPAs embed a no-take zone, aiming to preserve natural populations and ecosystems, within a buffer zone where potentially sustainable activities are allowed. Small-scale fisheries (SSF) within buffer zones can be highly beneficial by promoting local socio-economies. However, guidelines to successfully manage SSFs within MPAs, ensuring both conservation and fisheries goals, and reaching a win-win scenario, are largely unavailable. From the peer-reviewed literature, grey-literature and interviews, we assembled a unique database of ecological, social and economic attributes of SSF in 25 Mediterranean MPAs. Using random forest with Boruta algorithm we identified a set of attributes determining successful SSFs management within MPAs. We show that fish stocks are healthier, fishermen incomes are higher and the social acceptance of management practices is fostered if five attributes are present (i.e. high MPA enforcement, presence of a management plan, fishermen engagement in MPA management, fishermen representative in the MPA board, and promotion of sustainable fishing). These findings are pivotal to Mediterranean coastal communities so they can achieve conservation goals while allowing for profitable exploitation of fisheries resources.

Functional diversity and species turnover of benthic invertebrates along a local environmental gradient induced by an aquaculture unit: the contribution of species dispersal ability and rarity

The relation of macrobenthic species turnover (beta diversity) and species plylogenetic variation with functional diversity patterns, across an environmental gradient induced by an aquaculture unit, in a coastal area of the island of Lesvos (NE Aegean) has been investigated in this study. The contribution of rare species response and species dispersal ability in the variation of functional diversity patterns along the environmental gradient, on a spatio-temporal scale, has been also examined. Our results revealed that benthic functional diversity was decreasing monotonically with increasing species turnover rate and hence with increasing spatial variability along the environmental gradient. Increased environmental stress which was detected in the immediate vicinity of the fish cages resulted to low species functional redundancy, since different species didn’t perform the same functional role at the most disturbed part of the established gradient. Functional diversity patterns were found to be correlated with species population size, whereas a strong linear relationship was also detected with phylogenetic diversity patterns, thus supporting the claim that wider local taxonomic trees can support a wider range of species functions even in small spatial scales. Rare species loss seemed to be one of the dominant factors ruling functional diversity variation. Species with the minimum possible dispersal ability, which were mostly rare, tend to diminish both in species number and population size faster than species with wider dispersal ability towards the most disturbed areas. The aforementioned results indicate that rare species variation and endemic species loss are critical factors in determining functional diversity loss across a human-induced environmental gradient in soft bottom benthic communities.

Estimating lagoonal biodiversity in Greece: comparison of rapid assessment techniques

An attempt is made to compare the results of different rapid biodiversity assessment techniques at the pan-Mediterranean, sectorial and local levels. A uniform multivariate pattern exists at the pan-Mediterranean and national (sectorial) levels: lagoons can be different when they host only a few species, but as species numbers increase, lagoons become homogenous in composition. Multivariate techniques cannot distinguish anthropogenically-impacted lagoons from those, which are naturally disturbed. In the pan-Mediterranean context it is the higher taxonomic levels, but in the national and local context it is the most abundant macrobenthic groups (polychaetes, molluscs and crustaceans) and meiobenthos which provide patterns closest to that derived from the species level. Taxonomic distinctness indices applied to polychaete and mollusc inventories provide meaningful results at most levels and scales of observation. These indices seem to be robust enough to discriminate anthropogenically impacted from naturally disturbed lagoons.

Mediterranean lagoons revisited: weakness and efficiency of the rapid biodiversity assessment techniques in a severely fluctuating environment

The purpose of this paper is to test the performance of rapid biodiversity assessment techniques in the lagoonal environment at the pan-Mediterranean scale. The multivariate techniques can produce patterns of lagoonal biodiversity along the Mediterranean. Additionally, it is shown that the polychaete inventory can preferably be used rather than the aggregation of information at the family level for the purposes of rapid biodiversity assessment. These techniques, however, appear to be weak for the environmental assessment because they cannot detect differences between the naturally disturbed and the anthropogenically impacted lagoons. Both taxonomic distinctness indices are found to be robust in providing meaningful results for rapid biodiversity/environmental assessment when the crustacean inventory and the polychaete and molluscan ones are used for the estimation of the average taxonomic distinctness and of the variation in taxonomic distinctness values, correspondingly. Conversely, information on the distribution of the macrofaunal species to the Mediterranean lagoons appears to be inadequate for the needs of such rapid biodiversity assessment at a regional scale. It is suggested that information on ecological convergence of the macrofaunal species would probably provide biodiversity indices with additional power, at least in the lagoonal environment.

The meiofaunal community structure of a Mediterranean lagoon (Gialova lagoon, Ionian Sea)

Abstract The higher taxonomic structure of a meiofaunal community was investigated in an Eastern Mediterranean lagoon (Gialova lagoon, Ionian Sea). Seven stations were sampled on a seasonal basis during 1995–1996. Stations within the lagoon were found to support a maximum of 14 meiofaunal taxa with densities ranging from 17 to over 2000 individuals per 10 cm2. Nematodes were not always the most abundant taxa, although they dominated about half of the total 28 samples. Uni- and multivariate analyses were employed to study the community structure. The distribution pattern of the meiofaunal community varied both across the lagoon and over the seasons. On the basis of the spatial differences a meiofaunal coenocline, correlated with the degree of isolation, was observed, composed of mainly two zones: one defined by the area close to the marine channel and the other the more isolated area in the inner lagoon. Meiofaunal distribution pattern was not clearly correlated to one environmental variable, but rather to many, and spatial and seasonal effects could be seen.

The Yellow Gorgonian Eunicella cavolini: Demography and Disturbance Levels across the Mediterranean Sea

The yellow octocoral Eunicella cavolini is one of the most common gorgonians thriving in Mediterranean hard-bottom communities. However, information regarding its distribution and ecology in several parts of the Mediterranean is lacking, while population trends and conservation status remain largely unknown. We investigated 19 populations of E. cavolini over three representative geographic regions: the NW Mediterranean, CE Adriatic, and N Aegean. Focusing on the upper bathymetric range of the species (<40 m), data were collected on the populations’ upper depth limit, density, colony height, and extent of injury. A three-level hierarchical sampling design was applied to assess the existence of spatial patterns, using: a) regions (located thousands of km apart), b) localities within regions (tens to hundreds of km apart), and c) sites within localities (hundreds of m to a few km apart). In the NW Mediterranean and CE Adriatic, the upper distribution limit was at depths ≤15 m, whereas in the N Aegean most populations were found deeper than 30 m. Population density ranged between 4.46-62 colonies per m2, while mean colony height was 15.6±8.9 SD cm with a maximum of 62 cm. The NW Mediterranean sites were characterized by dense populations dominated by small colonies (<20 cm), periodic recruitment, and low proportion of large gorgonians (>30 cm). The CE Adriatic displayed intermediate densities, with well-structured populations, and continuous recruitment. In the N Aegean, most populations presented low densities, high proportion of large colonies, but low number of small colonies, signifying limited recruitment. Disturbance levels, as a function of extent and type of injury, are discussed in relation to past or present human-induced threats. This work represents geographically the most wide ranging demographic study of a Mediterranean octocoral to date. The quantitative information obtained provides a basis for future monitoring at a Mediterranean scale.

Community properties of benthic molluscs as indicators of environmental stress induced by organic enrichment

This study investigates the multivariate spatio‐temporal population patterns of molluscan taxocoenosis along an organic load gradient caused by the presence of a fish farm unit in the semi‐enclosed micro‐tidal Gera bay in the island of Lesvos (northeast Aegean), by exploring three different properties (species abundance, trophic web structure and geographic ranges) as indicators for detecting community disturbance. Results have shown that community properties related to ecosystem functioning (i.e. food web analysis) and macro‐ecological aspects (i.e. zoogeographical orientation community features) have proved to be more sensitive in detecting the effects of organic load perturbation than species abundance, thus indicating the use of such properties in environmental assessment approaches in the future.