Stefano Fenoglio

A ''Weight-of-Evidence'' Approach for the Integration of Environmental ''Triad'' Data to Assess Ecological Risk and Biological Vulnerability

ABSTRACT A new Expert Decision Support System (EDSS) that can integrate Triad data for assessing environmental risk and biological vulnerability at contaminated sites has been developed. Starting with ecosystem relevance, the EDSS assigns different weights to the results obtained from Triad disciplines. The following parameters have been employed: 1) chemical soil analyses (revealing the presence of potentially dangerous substances), 2) ecotoxicological bioassays (utilizing classical endpoints such as survival and reproduction rates), 3) biomarkers (showing sublethal pollutant effects), and 4) ecological parameters (assessing changes in community structure and functions). For each Triad discipline, the EDSS compares the data obtained at the studied field sites with reference values and calculates different 0–1 indexes (e.g., Chemical Risk Index, Ecotoxicological Risk Index, and Ecological Risk Index). The EDSS output consists of 3 indexes: 1) Environmental Risk Index (EnvRI), quantifying the level of biological damage at population–community level, 2) Biological Vulnerability Index (BVI), assessing the potential threats to biological equilibriums, and 3) Genotoxicity Index (GTI), screening genotoxicity effects. The EDSS has been applied in the integration of a battery of Triad data obtained during the European Union-funded Life Intervention in the Fraschetta Area (LINFA) project, which has been carried out in order to estimate the potential risk from soils of a highly anthropized area (Alessandria, Italy) mainly impacted by deposition of atmospheric pollutants. Results obtained during 4 seasonal sampling campaigns (2004–2005) show maximum values of EnvRI in sites A and B (characterized by industrial releases) and lower levels in site D (affected by vehicular traffic emissions). All 3 potentially polluted sites have shown high levels of BVI and GTI, suggesting a general change from reference conditions (site C).

The effect of a carotenoid-rich diet on immunocompetence and behavioural performances in Moorhen chicks

Carotenoids have attracted the attention of behavioural ecologists because of their modulatory effects on the immune system, colour expression and several physiological functions affecting body conditions. To evaluate whether carotenoid abundance influences growth, behavioural performance, immunocompetence and bill colour, we raised two groups of Moorhen chicks for 1 month with different food intakes (control diet versus carotenoid-rich diet). The two groups did not show significant differences in growth rate, nor in the red or yellow colouration of the bill, although there was a greater immune response in the carotenoid-rich group. Locomotor activity, tested in an open-field apparatus, did not differ between the two groups, but carotenoid-fed chicks showed more intense pecking at a model mimicking the parents. In this experiment, we demonstrated that carotenoid abundance can influence both immune and behavioural responses, with a greater availability of carotenoids being reflected in improved behavioural performance and immunocompetence.

Freshwater biodiversity in the rivers of the Mediterranean Basin

We review the diversity of freshwater organisms in the Mediterranean Basin (hereafter Med), particularly from streams and rivers. We present available information on the richness, endemicity, and distribution of each freshwater organism group within the Med, and make a comparison with Palearctic diversity. Approximately 35% of known Palearctic freshwater species and more than 6% of the World’s freshwater species are present in the Med. A high degree of endemicity is found in the Med freshwater biota. These data, together with the degree to which many freshwater species are threatened, support the inclusion of the Med among World biodiversity hotspots. Nevertheless, knowledge of Med biodiversity is still incomplete, particularly for some taxa. Regarding to the spatial distribution of species within the Med, the richest area is the North, although patterns differ among groups. A comparison of the ecological and biological traits of endemic and non-endemic species of three riverine groups (Ephemeroptera, Plecoptera, and Trichoptera) revealed that endemic species have several strategies and mechanisms to face typical mediterranean-climate conditions, such as drought, when compared to non-endemic species. We briefly analyse the conservation status of the region’s biodiversity. Finally, we present some future challenges regarding the knowledge and protection of Med freshwater biodiversity.

Field experiments on colonization and movements of stream invertebrates in an Apennine river (Visone, NW Italy)

Macroinvertebrates continuously redistribute themselves in the riverbed. A knowledge of the colonization mechanisms and movement patterns is very important for an understanding of processes of restoration of lotic environments, particularly of inland waters with severe pollution. We tested the colonization patterns of stream macroinvertebrates in the Visone River, a tributary of the highly contaminated Bormida River (NW Italy). We placed six groups of traps in the riverbed, each group consisting of three traps: the C trap allowed colonization from all directions, while the D and U traps allowed access only from downstream and upstream respectively. The C traps were the most colonized substrates, both in number of individuals and taxa. The U traps were more colonized than the D traps, demonstrating the great importance of movements directed downstream. We report data on taxonomic and seasonal differences in the colonization process.

Response of benthic invertebrate assemblages to varying drought conditions in the Po river (NW Italy)

In the rivers of northern Italy, the presence of water is typically continuous all year long, although in the last five decades there has been a conspicuous increase in drought periods, mainly caused by human impacts and climate change. The aim of this study was to assess the impact of the length of the drought periods on macroinvertebrate assemblages. We collected invertebrates in four reaches of the Po river, characterised by different periods of absence of surface water. We found significant differences among the stations in invertebrate abundance and taxa richness, with a decrease in the more drought‐affected stream reaches. Collector‐gatherers significantly increased as the drought period lengthened, while the opposite occurred for scrapers and shredders. The areas with a discontinuous presence of water were mainly colonised by small, fast‐growing, plurivoltine organisms. A main result of our study is that only a few taxa appear to be able to survive in reaches with intermittent flow, underlining the great ecological difference between perennial and naturally intermittent streams. Our results suggest that the recent increase of droughts will likely cause an impoverishment of benthic communities in prealpine rivers.

Life strategies of 3 Perlodidae species (Plecoptera) in a Mediterranean seasonal stream in southern Europe

Abstract We studied aspects of the nymphal biology and ecology of 3 Perlodidae species (Guadalgenus franzi, Hemimelaena flaviventris, and Isoperla curtata) in a Mediterranean seasonal stream in the southern Iberian Peninsula. Their life-history strategies were greatly influenced by the characteristics of their environment, i.e., a summer dry period with relatively warm temperatures, but strategies differed among species. Guadalgenus franzi was semivoltine and probably underwent nymphal quiescence when the stream was dry. Hemimelaena flaviventris and I. curtata had relatively short univoltine life cycles that overlapped, but I. curtata was slightly ahead of H. flaviventris. Both species passed the dry period in the egg stage, probably with a diapause phase. Growth rates of H. flaviventris and I. curtata peaked before emergence, whereas growth rate of G. franzi peaked immediately before and after the dry period. The 3 species had relatively short flight periods compared with other species from seasonal streams. Guadalgenus franzi and I. curtata were mainly scrapers that fed on diatoms, whereas H. flaviventris was mainly predatory. Diet changed somewhat in relation to size, and prey electivity patterns differed among species. All 3 species preferred Chironomidae, but G. franzi preferred Chironomidae principally when smaller. All 3 species had high secondary production relative to other stonefly species from both temporary and permanent waters.

Effects of global climate change on freshwater biota: A review with special emphasis on the Italian situation

Abstract There is much evidence that climate is rapidly changing at a global scale, especially regarding mean annual temperatures, precipitations and evaporation. The consequences of this rapid environmental change on freshwater biota are still not clear, but undoubtedly they could be severe. Among the main effects of climate change, we can individuate the enhancement of water temperatures, particularly important for poikilothermic organisms, with the consequent diminution of dissolved oxygen, and the reduction of available habitats for most stenothermal organisms. Another consequence of climate change is the alteration of hydrologic cycles, with increasing intensity and frequency of extreme events such as droughts, especially in Southern Europe. This scenario could severely affect freshwater biota, especially in mid-latitude regions, such as the Italian peninsula: shifts in phenology, life cycles and distribution ranges are likely to be expected for many organisms, with the extinction of many sensitive species. In particular, species adapted to perennial and cold waters are likely to suffer reductions in their distribution range and also local extinctions, while more tolerant organisms may enlarge their distribution ranges. Global climate change may also promote and enhance invasions of alien species. In this work, concepts and hypotheses about the presumable impacts of climate change upon freshwater biota are reported, with examples and predictions related to the Italian situation.

ENVIRONMENTAL QUALITY EVALUATION OF ALPINE SPRINGS IN NW ITALY USING BENTHIC DIATOMS

This study was undertaken to obtain a picture of the environmental quality of 6 springs in the Ligurian Alps, situated within the Natural Reserve of the Upper Pesio and Tanaro Valleys in the Piemonte Region of NW Italy. Benthic diatom communities were sampled in Spring, Summer and Autumn of 2001. Based on 98 identified taxa, diatom indices were calculated and statistical analyses were undertaken to integrate the information derived from the known ecological preferences of the diatoms. During the summer, activities, such as sheep and cattle pastures, water abstraction and recreation intensify. The EPI-D (Eutrophication Pollution Index—Diatoms) for all samples was calculated on the basis of the diatom communities. With few exceptions, the index was always within the first quality class. An index based on the proportion of motile diatom species (belonging to the genera Navicula, Nitzschia and Surirella) was adopted in this work. It indicated a slight degree of impact, in part caused by human activities, in two springs. The causes were ascribed to a combination of pasture and recreational activities. The Classification (TWINSPAN) and Ordination (CA) of diatom species distinguished 2 different pH preferences groups, while analyses by means of circle of correlations separated environmental variables and sample groups. The use of diatoms proved to be appropriate for the evaluation of springs and high altitude mountain brooks of the type considered in the present study. This important application could be used in the management of aquatic environments in alpine regions, including protected areas, where other standardized methods (including those based on macroinvertebrates) are difficult or impossible to use.

Mass loss and macroinvertebrate colonisation of fish carcasses in riffles and pools of a NW Italian stream

AbstractIn this study, we analysed the decomposition of trout carcasses in a low-order Apennine stream, with the aim to investigate the mass loss rate in a Mediterranean lotic system, and to examine the influence of microhabitats on the invertebrates colonising fish carcasses. In May 2003, we put 56 dead rainbow trout (Oncorhynchus mykiss) in the stream, placing seven sets (four trout each) in both riffle and pool habitats. At four dates, we removed one trout per set to measure its dry mass and determine the associated macroinvertebrate assemblage. Fifty-eight macroinvertebrate taxa colonised the carcasses, with significant differences between the erosive and depositional microhabitats. Riffle trouts hosted richer and denser colonist communities than pool trouts. Chironomidae, Serratella ignita, Habrophlebia sp., Dugesia sp. and Protonemura sp. were the five most abundant taxa. Decomposition was initially very rapid in both environments and then tapered off over time. The mass loss rate was higher (k= −0.057 day−1) than that found in other studies. Higher Mediterranean temperatures probably increase the process. Although we found no significant difference between riffles and pools, mass loss was more regular in erosive habitats, underlining the importance of local, small-scale conditions. In small, low-order, heterotrophic streams, fish carcasses represent an important resource and shelter for rich and diversified invertebrate assemblages.

Temporal and Spatial Patterns of Coarse Particulate Organic Matter and Macroinvertebrate Distribution in a Low-Order Apennine Stream

ABSTRACT We described the microdistribution of benthic macroinvertebrates in a 50 m riffle segment of the Rio del Giovo (Sassello, NW Italy) during a period of rapid loss of leaf mass, from March to May 2003. We analyzed the relationship between the taxonomic composition and functional organization of benthic communities and the availability of coarse particulate organic matter (CPOM), as well as the influence of micro-environmental characteristics (water velocity, depth, and substratum). Patches without CPOM hosted specialized communities. The temporal variation of CPOM influenced the distribution of functional feeding groups in the riverbed. In particular, shredder assemblages were widespread in the riverbed when CPOM was abundant, but when this resource became scarce and localized, their density was related to the availability of allochthonous organic detritus.