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 levels 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 influence of streambed sediment clogging on macroinvertebrate communities was investigated in the Lemme creek (NW Italy). To assess how fine sediment accumulation can influence the colonisation process and community composition of macroinvertebrates, we placed 48 traps in the riverbed. The traps consisted of boxes built with metal net (mesh 1 cm, height 15 cm, sides 5 cm) covered with nylon net except for the apex, allowing access exclusively from the top. We created four trap types filled with 100% gravel, 30% sand and 70% gravel, 70% sand and 30% gravel and 100% sand. After 20 and 40 days, we removed 6 traps/type. Macroinvertebrates rapidly colonised the traps, as we found no significant community differences between the two removal dates. Among the four trap types, we found significant differences in taxa number and abundance, which both decreased with increasing clogging. Thus, our study supports the hypothesis that clogging and the accumulation of fine substratum elements strongly affects benthic stream communities.

No abstract

Several mountain streams are currently changing from perennial to temporary due to increasing water abstraction and global climate change with expected detrimental effects on stream biodiversity and functionality. We here examined whether macroinvertebrates and diatoms, experiencing recurring non-flow periods, show alterations even after complete flow resumption in 13 mountain streams in SW Italian Alps. Benthic communities were sampled after complete flow resumption in April 2017 in a control section, with permanent flow, and an intermittent section, which experiences a non-flow period during summer, in each stream. We tested for differences in terms of taxonomic and functional composition, diversity and functional group composition between permanent and temporary sections. Our results showed a significant alteration of benthic invertebrate, but not diatom communities in temporary sections. Different species composition and low diversity values in temporary sections were due to the replacement of monovoltine taxa, with aquatic respiration, preferring medium to fast flowing, oligotrophic waters by plurivoltine taxa, with aerial respiration preferring lentic habitats. Such results provide some insights into the mechanisms by which non-flow periods impact Alpine streams, and further investigations in mountain areas are required in the future to better unravel the repercussions on stream ecosystem processes.

It is generally argued that epilithic diatoms and macroinvertebrates are highly sensitive to changes in water quality, while only a few studies have been conducted on their response to physical disturbance. The main purpose of this research is to investigate whether these two communities respond to physical river disturbance like banks, substrate and flux alteration induced by human action.We sampled 12 high-altitude streams in the Gran Paradiso National Park, a protected area where the main human activities are limited to hiking and high-altitude pasture. The sampled stretches of the rivers were characterized with respect to their geomorphological features and possible human modifications. Water uptake for power supply, riverbed and bank modifications represented the main human activities which could determinate alterations in community structure and composition. Habitat structure was evaluated using the Southern European River Habitat (RHS-SE), while the biological status of the river has been estimated by means of the following biotic and diatomic indices: IBE, BMWP, ASPT, Ephemeroptera, Plecoptera and Trichoptera families (EPT) for macroinvertebrates, EPI-D, IBD and IPS for diatoms. A general concordance between chemical parameters and structure of biological communities was observed. On the other hand, the RHS-SE highlighted the main geomorphological features and detected some slight physical alterations, as quantified by the indices Habitat Modification Score (HMS) and Habitat Quality Assessment (HQA). In short, our findings demonstrate that morphological alterations, even if slight, affect biological diversity and the presence of some specific taxa, while biological indices are independent of the level of physical modifications.