Spatial management of the Mediterranean bottom-trawl fisheries: the case of the southern Aegean Sea

A time series of survey abundance indices for commercially important demersal fish and cephalopod species, inhabiting the narrow continental shelf of the southern Aegean Sea, is analyzed in relation to the topography of the area in order to evaluate the impact of different spatial fishery bans on the bottom-trawl fishery. With reference to the current situation, results suggested that implementation of the 1967/2006 EC Regulation, which bans bottom-trawl activities within 1.5 NM off the coast, will significantly increase (20–80%, depending on the species) the proportion of the populations that are inaccessible to the bottom-trawl fishery. It might also result in shifting of fishing activities toward deeper waters, adding fishing pressure onto slope resources inhabiting the slope. As depth determines, to a large extent, the distribution pattern of the species, it constitutes a variable of crucial importance for the spatial management of marine fisheries and should be taken into account when adopting relevant management regimes.     

Reevaluating sponge diversity and distribution in the Mediterranean Sea

The aim of this paper was (1) to update sponge diversity and distribution in the Mediterranean and (2) to re-examine faunal relationships among the Mediterranean areas on the basis of their sponge fauna. The Mediterranean demosponge faunal list was updated to 629 species by taking into consideration recent data from previously poorly studied areas. The species lists of 14 Mediterranean areas were compared on the basis of their sponge species richness, species composition, and taxonomic relatedness of species using multivariate analyses and diversity measures, such as PD, Delta+, and Lambda+. The 14 Mediterranean areas examined for their diversity and affinities were assembled into four major zoogeographic groups: the northwestern, northeastern, the central zone, and southeastern areas. Richest in species numbers were the areas belonging to the two northern groups. The species richness comparisons and similarity analyses performed at the generic level showed that it can be safely used as a surrogate for sponge species diversity in the Mediterranean. The results of this study showed that the simple traditional division of the Mediterranean Sea into a western, central, and eastern basin cannot reliably describe the distribution of sponges in the area. Thus, the W to E faunal decline previously presented for several faunal groups shifts to a general NNW-SSE pattern when one examines separately the northern and the southern parts of the traditional basins. This gradient seems to be in agreement with differences in key environmental variables, such as latitude, salinity, temperature, and water circulation, besides the typically examined distance from Gibraltar. Handling editor: T. P. Crowe     

Marine caves of the Mediterranean Sea: a sponge biodiversity reservoir within a biodiversity hotspot

Marine caves are widely acknowledged for their unique biodiversity and constitute a typical feature of the Mediterranean coastline. Herein an attempt was made to evaluate the ecological significance of this particular ecosystem in the Mediterranean Sea, which is considered a biodiversity hotspot. This was accomplished by using Porifera, which dominate the rocky sublittoral substrata, as a reference group in a meta-analytical approach, combining primary research data from the Aegean Sea (eastern Mediterranean) with data derived from the literature. In total 311 species from all poriferan classes were recorded, representing 45.7% of the Mediterranean Porifera. Demospongiae and Homoscleromorpha are highly represented in marine caves at the family (88%), generic (70%), and species level (47.5%), the latter being the most favored group along with Dictyoceratida and Lithistida. Several rare and cave-exclusive species were reported from only one or few caves, indicating the fragmentation and peculiarity of this unique ecosystem. Species richness and phylogenetic diversity varied among Mediterranean areas; the former was positively correlated with research effort, being higher in the northern Mediterranean, while the latter was generally higher in caves than in the overall sponge assemblages of each area. Resemblance analysis among areas revealed that cavernicolous sponge assemblages followed a pattern quite similar to that of the overall Mediterranean assemblages. The same pattern was exhibited by the zoogeographic affinities of cave sponges: species with Atlanto-Mediterranean distribution and Mediterranean endemics prevailed (more than 40% each), 70% of them having warm-water affinities, since most caves were studied in shallow waters. According to our findings, Mediterranean marine caves appear to be important sponge biodiversity reservoirs of high representativeness and great scientific interest, deserving further detailed study and protection.     

Re-plumbing in a Mediterranean sponge

Observations are reported for Dysidea avara sponges where once functioning oscula (outlets) are converted through internal re-plumbing into functioning oversized ostia (OSO; inlets). Flow tank studies employed high-speed photography and particle tracking of laser-illuminated 0.5-6.0 microm diameter glass beads to trace particles streaming into OSO. A fluorescein dye/glass bead uptake experiment showed that an oversized ostium was connected through internal structures to the lone osculum. Beginning 30 s after uptake and continuing over a 20 min period, dye streamed from the osculum, but no beads emerged. Scanning electron microscopy revealed that beads were deposited only on the inhalant side of particle filtering choanocyte chambers and not on the exhalant side, suggesting that internal re-plumbing had occurred. Functioning OSO were also found on freshly collected specimens in the field, making it highly unlikely that formation of OSO was only an artefact of sponges being held in a laboratory tank.     

Plant species diversity in Mediterranean old-growth forests: A case study from central Italy

Abstract

To investigate the differences in understorey composition and diversity between old-growth and managed forests, we analyzed an old-growth and a managed beech stand in the same area displaying similar abiotic features. We considered variations in understorey species composition and richness. The sampled understorey species were characterized in terms of functional traits, Ellenberg's indicator values and taxonomic distinctness; next, we calculated four different pairwise plot-to-plot dissimilarity matrices based on species composition, functional traits, Ellenberg's indices and taxonomic distances. We applied a permutational multivariate extension of ANOVA to test whether the forest stands significantly differ in the considered features. Indicator values of all plant species in managed and old-growth stands were evaluated.

The old-growth forest had a higher species richness; permutational analysis of variance showed significant differences between the two stands in plant species composition, functional traits, Ellenberg indices and taxonomic distances. Indicator species analysis highlighted 14 indicator species for the unmanaged stand, while only 3 indicators were found for the managed one.

The results suggest that forest management determines ecological differences that strongly affect plant species composition.

The knowledge of natural stands dynamics could allow development of new approaches and practices in forest management focusing on biodiversity conservation.     

Preliminary insights of a mixed-species shark aggregation: a case study of two carcharhinids from the Mediterranean Sea

Environmental Biology of Fishes - Social and non-social animals can aggregate at a specific site for various reasons such as reproduction, feeding, or other synchronized patterns of movements....     

Atlantis II Cruise: uniformity of deep copepod assemblages in the Mediterranean Sea

Studies of the community structure and biomass of deep copepodsbelow 500 m from R/V Atlantis II cruises AII49 and AII59 inMay–June 1969 and September–October 1970 denoteuniformity in deep assemblages among all major Mediterraneansubregions. Of the 65 copepod species recorded from 600–2500m, 45 were common for both Western and Eastern basins Eightof these species were dominant for all deep Mediterranean waters,comprising 77% of the deep plankton population The uniformityof deep copepod assemblages was confirmed by the Mantel testapplied to a simulated sampling procedure Only in terms of biomassdid Western and Eastern basins show appreciable regional differenceswith highest values for density and volume characterizing Westernstations ¹Died tragically at sea during the course of a cruise on December15, 1988     

The impact of fisheries on vulnerable habitats: the case of trawling on circa-littoral grounds in the Strait of Sicily (central Mediterranean Sea)

The Council Regulation (EC) no. 1967/2006 introduced the adoption of the 40 mm square-mesh or alternatively a 50 mm diamond-mesh codend for trawlers of EU Member States. In this context, the main aim of the current study was to compare the catch composition of Lampedusa’s shallow-water trawl fishery, in terms of retained and discarded fraction, using the 24 mm square-mesh codend (illegal and supposed unselective) and the 50 mm current diamond-mesh codend (legal and supposed selective). During 2012, 21 hauls were performed, under commercial conditions, with the 24 mm square mesh codend and 27 with the 50 mm diamond mesh codend in an area of the Strait of Sicily at depths from 40 to 80 m. The introduction of a 50 mm diamond-mesh, although not significantly, reduced the CPUEs of retained and discarded fraction compared with the 24 mm mesh. Moreover, for most target species and their size classes (especially immature individuals), the legal mesh recorded a lower mean number of specimens than the banned mesh size. All these advantages aside, the discard of the shallow-water trawl fishery, in Lampedusa, represented a very important part of the total catch (more than three-quarters) by both mesh sizes and a large amount of this was represented by species and habitat of conservation concern. Our results suggest that spatial restrictions, such as no-take zones, could be a more effective management tool to protect this sensitive ecosystem in the area than the technical measures (e.g. reduction of mesh size) imposed today by the EU.     

Hake,Merluccius merluccius L., in the northeastern Mediterranean Sea: a case of disappearance

Hake was not an important commercial fish in the northeastern Levant until the 1990s when a sudden increase in landings was experienced. However, following a series of profitable years, landings declined sharply. The rapid development of the trawl fleet played a role in the decline; however such an episodic event cannot be explained within the fisheries context alone. In this study the results of sparse historical trawl surveys were evaluated together with oceanographic data, and the impact of hydrographical changes on the appearance/disappearance of hake in the Levant was considered. The formation and movement of different water masses in the area seem to have primary importance for the species. The winter occurrence of modified Atlantic water that temporarily intrudes in the region may favour hake. Parallel with the increase in hake, an increase in clupeid species not common in the area was also observed. The change in the hydrography of the region, which was probably linked to the cold period that prevailed at the same time, temporarily led to an additional late summer pulse in the production cycle. The consequent increase in clupeids along with the changes in the hydrology favoured the advent of clupeid‐eating hake in the NE Levant. The growth pattern result of the modal shift in monthly length‐frequency distributions also showed that the species underwent a rapid growth phase in winter, which was most likely associated with intense feeding.     

Extending the temporal context of ethnobotanical databases: the case study of the Campania region (southern Italy)

Background

Medicinal plants are the integral part of the variety of cultures in Ethiopia and have been used over many centuries. Hence, the aim of this study is to document the medicinal plants in the natural vegetation and home gardens in Wonago Woreda, Gedeo Zone, Southern Nations, Nationalities and Peoples Regional State (SNNPR).

Materials and methods

Thirty healers were selected to collect data on management of medicinal plants using semi-structured interview, group discussion, and field observation. The distribution of plant species in the study areas was surveyed, and preference ranking, direct matrix ranking, priority ranking of factors and Informant consensus factor (ICF) were calculated.

Results

The informants categorized the vegetation into five community types based on plant density and associated landform: 'Raqqa', 'Hakka cadanaba', 'Mancchha', 'Bullukko', and 'Wodae gido'. 155 plant species were collected from the natural vegetation and 65 plant species from the home gardens ('Gattae Oduma'). Seventy-two plant species were documented as having medicinal value: Sixty-five (71%) from natural vegetation and 27 (29%) from home gardens. Forty-five (62%) were used for humans, 15(21%) for livestock and 13(18%) for treating both human and livestock ailments: 35 (43.2%) were Shrubs, 28(34.5%) herbs, 17 (20.9%) trees and 1(1.2%) climbers. The root (35.8%) was the most commonly used plant part. The category: malaria, fever and headache had the highest 0.82 ICF. Agricultural expansion (24.4%) in the area was found to be the main threat for medicinal plants followed by fire wood collection (18.8%). Peoples' culture and spiritual beliefs somehow helped in the conservation of medicinal plants.

Conclusion

Traditional healers still depend largely on naturally growing plant species and the important medicinal plants are under threat. The documented medicinal plants can serve as a basis for further studies on the regions medicinal plants knowledge and for future phytochemical and pharmacological studies.     

Directional biases in phylogenetic structure quantification: a Mediterranean case study

Recent years have seen an increasing effort to incorporate phylogenetic hypotheses to the study of community assembly processes. The incorporation of such evolutionary information has been eased by the emergence of specialized software for the automatic estimation of partially resolved supertrees based on published phylogenies. Despite this growing interest in the use of phylogenies in ecological research, very few studies have attempted to quantify the potential biases related to the use of partially resolved phylogenies and to branch length accuracy, and no work has examined how tree shape may affect inference of community phylogenetic metrics. In this study, we tested the influence of phylogenetic resolution and branch length information on the quantification of phylogenetic structure, and also explored the impact of tree shape (stemminess) on the loss of accuracy in phylogenetic structure quantification due to phylogenetic resolution. For this purpose, we used 9 sets of phylogenetic hypotheses of varying resolution and branch lengths to calculate three indices of phylogenetic structure: the mean phylogenetic distance (NRI), the mean nearest taxon distance (NTI) and phylogenetic diversity (stdPD) metrics. The NRI metric was the less sensitive to phylogenetic resolution, stdPD showed an intermediate sensitivity, and NTI was the most sensitive one; NRI was also less sensitive to branch length accuracy than NTI and stdPD, the degree of sensitivity being strongly dependent on the dating method and the sample size. Directional biases were generally towards type II errors. Interestingly, we detected that tree shape influenced the accuracy loss derived from the lack of phylogenetic resolution, particularly for NRI and stdPD. We conclude that well‐resolved molecular phylogenies with accurate branch length information are needed to identify the underlying phylogenetic structure of communities, and also that sensitivity of phylogenetic structure measures to low phylogenetic resolution can strongly vary depending on phylogenetic tree shape.     

Role of urban green spaces for saproxylic beetle conservation: a case study of tenebrionids in Rome,Italy

Forested urban areas provide many important ecosystem services and their preservation is considered of paramount importance. Although urban forest are known to host a high diversity of saproxylic beetles (i.e. those associated with dead wood), contributions dealing with the role of urban green spaces for their conservation are lacking. We investigated the importance of urban green spaces for saproxylic and non-saproxylic tenebrionid beetles in urban Rome. Based on species vulnerability scores we calculated two indices of area prioritisation, the Biodiversity Conservation Concern (BCC) and the Biodiversity Conservation Weight (BCW) for saproxylic and non-saproxylic species. Site area and forest surface correlated positively with saproxylic richness, whereas site isolation correlated negatively with non-saproxylic richness. BCC and BCW values for saproxylic species were positively correlated with distance from the city centre. For non-saproxylic species, BCW values were negatively correlated with distance from adjacent areas. These results suggest that saproxylic beetles require large areas covered by forest, but are not strongly influenced by isolation, which is important for non-saproxylic species. Non-saproxylic tenebrionids have limited dispersal capabilities, which explains their sensitivity to isolation, but are generally eurytopic species frequently found even in the city centre. By contrast, most saproxylic species are able to fly, but are mainly found in peripheral areas with large and relatively well preserved forest fragments. Maintaining and possibly enhancing connectivity among green spaces is important for the conservation of non-saproxylic species, whereas preserving large forest surfaces, especially in peripheral areas, is needed for the conservation of saproxylic species.     

Habitat loss and possible effects on local species richness in a species-poor system: a case study of southern Baltic Sea macrofauna

The effects of habitat loss on local species richness depend on the characteristics of the endangered system (including its total species pool and the distribution of species among the habitats). The present study focuses on the species-poor southern Baltic marine benthic biota. Macrobenthic samples were collected in three habitats: (1) soft bottom covered with vegetation; (2) stony reefs; (3) unvegetated sands. Fourty one percent of 54 observed macrozoobenthic species were habitat specific, while 30% occurred in all three habitats. There were no significant differences in total species richness among the three habitats. The accumulation curves plotted for subsets of data with selected habitats excluded lay below the curve plotted for the whole dataset, but only in one case the 95% confidence intervals of the subset curve did not overlap with those plotted for the whole dataset. The exclusion of samples from selected habitats produced a species richness drop ranging from 9 to 13%. The present study showed that habitat loss in a species-poor area with a relatively large ratio of generalist species cannot produce local species richness declines similar to those predicted for diverse marine systems. However, it must be emphasized that in species-poor systems, the loss of ecological function accompanying habitat loss could be disproportionally higher than that predicted based on decreases in species richness, as some functions are performed by a single species.     

Phylogenetic diversity of sediment bacteria from the southern Cretan margin,Eastern Mediterranean Sea

This study is the first culture-independent report on the regional variability of bacterial diversity in oxic sediments from the unexplored southern Cretan margin (SCM). Three main deep basins (water column depths: 2670–3603 m), located at the mouth of two submarine canyons (Samaria Gorge and Paximades Channel) and an adjacent slope system, as well as two shallow upper-slope stations (water column depths: 215 and 520 m), were sampled. A total of 454 clones were sequenced and the bacterial richness, estimated through five clone libraries using rarefaction analysis, ranged from 71 to 296 unique phylotypes. The average sequence identity of the retrieved Cretan margin sequences compared to the >1,000,000 known rRNA sequences was only 93.5%. A diverse range of prokaryotes was found in the sediments, which were represented by 15 different taxonomic groups at the phylum level. The phylogenetic analysis revealed that these new sequences grouped with the phyla Acidobacteria, Planctomycetes, Actinobacteria, Gamma-, Alpha- and Delta-proteobacteria. Only a few bacterial clones were affiliated with Chloroflexi, Bacteroidetes, Firmicutes, Gemmatimonadetes, Verrucomicrobia, Nitrospirae, Beta-proteobacteria, Lentisphaerae and Dictyoglomi. A large fraction of the retrieved sequences (12%) did not fall into any taxonomic division previously characterized by molecular criteria, whereas four novel division-level lineages, termed candidate division SCMs, were identified. Bacterial community composition demonstrated significant differences in comparison to previous phylogenetic studies. This divergence was mainly triggered by the dominance of Acidobacteria and Actinobacteria and reflected a bacterial community different from that currently known for oxic and pristine marine sediments.     

Effective reassessments of freshwater fish species: a case study in a Mediterranean peninsula

Hydrobiologia - IUCN Red List assessments for fish species can quickly become out of date. In recent years molecular techniques have added new ways of obtaining information about species...     

A preliminary study of tintinnid diversity in the NW Mediterranean Sea

Tintinnid diversity in surface waters was investigated in the Bay of Villefranche in March, before the formation of the seasonal thermocline, and in May, following water column stratification. Tintinnid abundance was much greater in March (500 cells l^-1), corresponding to a bloom of Stensomella nivalis compared to May (30 cells l^-1). Nonetheless, high numbers of species were encountered on both dates: 32 in March and 39 in May, respectively. Diversity was higher (H2.5) for the May date with low tintinnid concentrations. We examined taxonomic diversity and morphological diversity. Variance of lorica length was correlated with taxonomic diversity, in contrast to variance of lorica diameter, which was nearly invariant. We suggest that either species with similar lorica diameters exploit different prey items or competition for prey items is not the dominant factor in structuring tintinnid communities.      

Product environmental footprint of a cross-laminated timber system: a case study in Italy

Purpose

This study aims to apply the product environmental footprint (PEF) methodology to a wooden wall element, the Massiv–Holz–Mauer® (MHM), in an existing building in Northern Italy. The PEF is a multi-criteria measure of the environmental performance of products throughout their life cycle (European Commission 2013).

Methods

The environmental footprint of the MHM wall element was calculated for the impact categories required by the PEF, using a cradle-to-grave approach. Foreground data was collected at each life stage and completed using data from the Ecoinvent 3.1 database (Wernet et al. 2016). An additional analysis (optional according to the PEF methodology) was conducted for assessing the sustainability of forest management in the sites where wood is extracted from, using data from the forest management plan.

Results and discussion

The results show that, for most of the environmental indicators, the use phase has the highest environmental impact, followed by the production, end-of-life, raw material acquisition, and construction phases. These results depend on the different duration of the life cycle phases, and on the attribution of the total operational energy of the building to the structural components of the wall, though other factors, such as the efficiency of the heating system, may be responsible. Future PEF sectorial specification should specify how to account for the use phase of structural building components. For the majority of the impact categories, the impact is mainly due to processes that occur in the background system, such as production of capital goods and construction of facilities and storehouses. The wooden material production generates relatively low impacts, thanks to the fact that the wood is sourced locally and from forests where a close-to-nature forest management is adopted, characterized by natural regeneration without the use of fertilizers and pesticides.

Conclusions

This study shows that the PEF methodology can be successfully applied to a single wood supply chain, allowing the identification of the main hotspots and actions for reducing the environmental impacts. The PEF leaves space for additional environmental information, which, for some product categories, may play an important role. In the case of wood products, we suggest the inclusion of an assessment, even qualitative, of the sustainability of forest management.

     

Phytoplankton assemblage at equilibrium in large and deep subalpine lakes: a case study from Lago Maggiore (N. Italy)

In 1996, we studied the phytoplankton seasonal succession in Lago Maggiore (N. Italy) through weekly sampling. Such a frequency enabled us to evaluate the changes of the phytoplankton assemblage in the light of the equilibrium and non-equilibrium theories. The distinct phases of changing of the species composition were identified separating the samples by means of cluster analysis and non-metric multidimensional scaling (NMDS). We recognised well distinct phytoplankton associations, whose seasonal succession followed a clear cyclic path throughout the year, with spring and summer phases respectively characterised by a rapid turn-over of the assemblages and by a relative stability. Moreover, we observed an increase of species number and Shannon-Wiener diversity during the spring, followed by a summer decline of the diversity in spite of an unchanged species number. Because of the dominance of the same few species for about two months during summer, coupled with small fluctuations of the total biomass, we could identify the summer assemblage as a steady state assemblage. The aim of the present contribution, although describing the whole seasonal succession, is to draw the attention towards the species composition at the steady state, taking into account the functional properties of the species involved. The possible role of the metalimnetic niche in selecting a particular summer assemblage in deep and large lakes will be discussed.     

Testing indicators of epiphytic lichen diversity: a case study in N Italy

The predictability of a standardized and widely used biomonitoring method for estimating total lichen diversity on trunks (LDV-index) was tested. The study was carried out in Veneto (NE Italy), on 34 randomly selected trees in five sites in different landscape contexts. Two sets of biodiversity data were obtained from each tree: (1) the LDV index based on species frequency within a standard sampling grid positioned on a limited part of the trunks only (2) the total number of species found on the trunks. Total species richness on trunks is significantly related with the LDV index, which suggests that the LDV standard methodology can be used also for estimates of lichen diversity. Even a LDV index based on macrolichens, or on large-lobed foliose lichens only, still permits reliable estimates of total diversity on the trunks.