Do carabids (Coleoptera: Carabidae) and chironomids (Diptera: Chironomidae) exhibit similar diversity and distributional patterns along a spatio-temporal gradient on a glacier foreland?

Carabid beetles and chironomid midges are two dominant cold-adapted taxa, respectively on glacier forefiel terrains and in glacial-stream rivers. Although their sensitivity to high altitude climate warming is well known, no studies compare the species assemblages exhibited in glacial systems. Our study compares diversity and distributional patterns of carabids and chironomids in the foreland of the receding Amola glacier in central-eastern Italian Alps. Carabids were sampled by pitfall traps; chironomids by kick sampling in sites located at the same distance from the glacier as the terrestrial ones. The distance from the glacier front was considered as a proxy for time since deglaciation since these variables are positively correlated. We tested if the distance from the glacier front affects: i) the species richness; ii) taxonomic diversity; and iii) species turnover. Carabid species richness and taxonomic diversity increased positively from recently deglaciated sites (those c. 160 m from the glacier front) to sites deglaciated more than 160yrs ago (those located >1300 m from glacier front). Species distributions along the glacier foreland were characterized by mutually exclusive species. Conversely, no pattern in chironomid species richness and turnover was observed. Interestingly, taxonomic diversity increased significantly: closely related species were found near the glacier front, while the most taxonomically diverse species assemblages were found distant from the glacier front. Increasing glacial retreat differently affect epigeic and aquatic insect taxa: carabids respond faster to glacier retreat than do chironomids, at least in species richness and species turnover patterns

Glacial Biodiversity: Lessons from Ground-dwelling and Aquatic Insects

At first glance, the ground surrounding the glacier front and the streams originated by melting glaciers seem to be too extreme to host life forms. They are instead ecosystems, colonized by bacteria, fungi, algae, mosses, plants and animals (called the “glacial biodiversity”). The best adapted animals to colonize glacier surface, the recently deglaciated terrains and glacial streams are insects, specifically the ground beetles (carabids) and the non-biting midges (chironomids). This chapter aims to overview the species colonizing these habitats, their adaptation strategies to face natural cold and anthropogenic heat and the extinction threats of glacial retreat and pollution by emerging contaminants. Notes on their role in the glacial-ecosystem functioning and related ecosystem services are also given

Tools for the development of a benthic quality index for Italian lakes

In this paper, we propose a methodology to develop a benthic quality index useful for Italian lakes. The existing data about benthic macroinvertebrates of the Italian lakes were collected over a period of 50 years, but only a few lakes such as the Maggiore and the Mergozzo have been intensely studied. Some large lakes such as Lake Como are still almost uninvestigated. In total, 570 benthic macroinvertebrate taxa were identified; of which 373 belong to Chironomidae and 85 to Oligochaeta. With the aim of relating environmental variables with macrobenthos assemblages, we carried out a canonical correlation analysis (CANON) using a database that included 1060 sampling points. Both environmental (13 variables describing morphometry and hydrochemistry) and biological data (57 taxa) were available, but only taxa present in at least 10 samples were selected for data analysis. Three canonical variates were ecologically significant. The first one was correlated with conductivity, pH and alkalinity and accounted for 20% of the total variation. The second one was positively correlated with total phosphorus and N-NH4, and inversely with dissolved oxygen, and accounted for 18% of the total variation. The third one showed a direct correlation with maximum lake depth and volume and an inverse correlation with water temperature, and accounted for 17% of the total variation. A Trophic Status Index (TSI), based on the table 11 of the Italian Law 152/99 (without including chlorophyll), was calculated by ranking percent oxygen saturation, transparency and total phosphorus. TSI was used to test a Benthic Quality Index for Italian Lakes (BQIL) which is proposed in the present paper. The algorithm considered three steps. First, the means of three variables were calculated: percent oxygen saturation, transparency and total phosphorus weighted by the taxa abundances. These values are interpreted as optimum for each taxon and used to assign an indicator weight (BQIW). Second, the mean of these three variables was calculated for each taxon (mean BQIW). Third, the mean BQIW was multiplied by taxa abundance and divided by the total number of specimens present at each site for which the BQIL was obtained. Using a regression between BQIL and TSI values, lake sites were assigned to 5 quality classes as required by the Italian Law 152/99 and the WFD 2000/60/CE. This assignment must be considered as tentative, because different lake types should be considered separately to develop an index. At present the lack of information from different lake typologies hinders the development of a more sophisticated index such as the French Lake Biotic Index (LBI).Studio iniziale per la messa a punto di una metrica (indice di qualit?) delle acque dei laghi Italiani con l\u27utilizzo del macrobenthos per l\u27assegnazione dei suddetti laghi a 5 categorie di qualit?, cos? come previsto dalla Direttiva Quadro sulle Acque (WFD 2000/60/CE). Sono presentati dati abiotici (parametri considerati dalla Legge 152/99) e biotici che sono risultati correlati all\u27idrochimica lacustre. Nel lavoro si evidenziano carenze sulla presenza di alcune tipologie lacustri presenti in Italia

Guida tecnica alla programmazione del campionamento e alla scelta della strumentazione idonea per lo studio della fauna macroinvertebrata lacustre

No abstract availableQuesta guida nasce dall\u27esigenza crescente a livello nazionale di fornire a coloro che si occupano direttamente del campionamento dei macroinvertebrati in ambiente lacustre, siano essi ricercatori alle loro prime esperienze, studenti od operatori delle Agenzie Ambientali, gli strumenti conoscitivi necessari per poter programmare al meglio l\u27attivit? di campo e di laboratorio e ottenere risultati standardizzati. L\u27adozione di un protocollo comune consente di ottenere la compatibilit? delle informazioni provenienti da siti ed Enti diversi, la confrontabilit? fra siti ed, all\u27interno dello stesso sito, fra stazioni e/o fra anni diversi. Per attuare quanto detto, si ? fatto riferimento ad una vasta letteratura, volumi e singole pubblicazioni datate, non reperibili via internet e quindi non facilmente accessibili, soprattutto a persone che affrontano per la prima volta il campionamento e lo studio del bentos di un lago, senza provocare frustrazioni o dar luogo a risultati dubbi. La guida prende dapprima in considerazione le principali tipologie lacustri riconosciute a livello nazionale, proponendo differenze di approccio e di programmazione a seconda dei diversi ambienti; passa poi in rassegna le strategie di campionamento adatte alle diverse tessiture di substrato, considerando anche l\u27ambiente terrestre ed aereo circostante la conca lacustre, per approfondimenti tassonomici; riassume le metodologie di trattamento dei campioni sul campo ed in laboratorio; ed infine considera anche altre variabili fisico-chimiche dell\u27acqua e dei sedimenti che possono risultare molto utili ai fini della descrizione dell\u27ambiente di studio e di una classificazione di qualit? delle acque. In conclusione, il fine generale di questo lavoro ? la scelta di elementi di base per una corretta impostazione di un\u27attivit? di campo e per la soluzione dei numerosi problemi gestionali nel campo della limnologia, della pianificazione di attivit? di ricerca e monitoraggio, del controllo ecologico, della difesa della qualit? dell\u27ambiente e della conservazione della natura. Attualmente, la normativa vigente ? infatti carente dal punto di vista delle direttive scientifiche e pratiche, si ? quindi pensato di organizzare tali informazioni, formulando proposte per rispondere ai problemi pi? comuni

Dragonfly biodiversity 90 years ago in an Alpine region: The Odonata historical collection of the MUSE (Trento, Italy)

Historical collections of natural science museums play a fundamental role in documenting environmental changes and patterns of biodiversity transformation. This considered, they should have a pivotal role to plan conservation and management actions. The MUSE - Science Museum of Trento is an Italian regional museum preserving about 5.5 million items (organised in 297 collections). About one million of them are invertebrates, 70% of which are of local origin, gathered in the collection "Miscellanea Invertebrati". Odonata account for a minor part of this collection; however, most of them are of local or regional relevance. A complete catalogue of this collection does not exist to date. The collection was studied in 2017-2018 and this contribution aims to present the Catalogue of the historic collection of Odonata of the MUSE - Museo delle Scienze of Trento (Italy). In all, 836 specimens of adult dragonflies and damselflies are found in the collection referring to an overall 56 species. The collection covers a period between 1924 and 1957 and refer to 74 defined localities, all located in northern Italy (most of them in Trentino - Alto Adige Region). The samples conserved in the collection are, for several species, the only indisputable confirmation of their former occurrence in that region

Is it possible to study paleoenvironmental changes in Alpine spring habitats? A few examples from the south-eastern Alps (NE Italy)

Palaeolimnological techniques were applied to spring habitats in the Trentino Region (NE Italy) as a test in order to reconstruct past environmental changes in these crucial and fragile milieus. Three different sites were selected from a database of more than one hundred on the basis of morphological, geological, and biological factors, including human impact evaluation: Nambrone, Paul and Madonnina Val Lomasona. Sampling was performed by adapting standard lake-sediment coring methods, and the retrieved sediment was described and subsampled following standard "lake" procedures. Field work and sedimentological analyses revealed clear influence from nearby fluvial environment for the Nambrone site, whereas Paul and Madonnina Val Lomasona were selected for further analyses (e.g., dating, diatoms, chironomids). Lead-210 and Caesium-137 dating methods were used to obtain a chronological framework, in addition to historical information on land use and other events in the area. The upper part of the Paul sequence presented organic rich sediment compatible with spring environments, but the lower and essentially detrital part appeared to record alluvial deposition, probably linked to extraordinary flood events (1882, 1966). This interpretation is indirectly confirmed by the records of the fallout nuclides Caesium-137 and Lead-210, that were both unfortunately concentrated in the topmost 1 cm, making it impossible to construct a normal age-depth profile. Madonnina Val Lomasona sedimentological and biological indicators point to a marked change around ca 5 cm, dividing the sequence in two units, corresponding to different environmental conditions. Although the interpretation of the dating results is not completely straightforward, the assembled data suggest that the upper 5 cm of the record represents ca the last 50 years. During this period we found typical limnocrenic, clear-water spring conditions, while before 1960s the coexistence of lotic and lentic chironomid species including several opportunistic ones and the low richness, emphasized the presence of a disturbance (e.g., highly variable flow and/or trophic conditions), as confirmed also by diatom assemblages and sedimentological features. The recorded disturbance is probably linked to a water-level change due to the local land use, as also testified by historical data. The results of this study support the idea that carefully selected spring sites might be approached with adapted palaeolimnological techniques to extract valuable palaeoenvironmental information. However, it also highlighted the low percentage of "good sites" (1%) and considerable difficulties in coring and sampling without disturbing the sediment

Protocollo di campionamento e analisi dei macroinvertebrati negli ambienti lacustri

No abstract availableIn questo documento vengono sintetizzate le principali tecniche di campionamento dei macroinvertebrati di ambiente lacustre. Si propongono metodologie standardizzate a livello nazionale utili per il monitoraggio previsto secondo le richieste della Direttiva Quadro sulle Acque (2000/60/CE)

Recent advances in the study of Chironomidae: An overview

This special issue provides an overview of recent advances in the study of chironomids (Diptera chironomidae), as an outcome of the 20th International Symposium on Chironomidae held in Trento (Italy), in July 2017. it includes 27 selected papers, representative of the six topics of the symposium: genetics and cytogenetics, taxonomy and systematics, autecology and physiology, toxicology and adaptive biology, ecology and biomonitoring, palaeolimnology. Most papers emphasise the value of chironomids in the monitoring programmes, mainly on Europe and case histories from South America and Africa. however, as our title indicates, the reported contemporary studies represent a range from the genetic through the autecological to the ecosystem scale. the aim of the volume is to give new insights on ecology and biology of non-biting midges, the freshwater insect family that comprises the highest number of species in the world, in both lentic and lotic habitats

Effects of human impacts on diversity and distribution of chironomids (Diptera: Chironomidae) in prealpine springs

Diversity and distribution of chironomid fauna (Diptera: Chironomidae) in 36 springs in the Italian Prealps (Veneto and Trentino NE-Italy, 46°N, 10-11°E) was studied in relation to altitude, spring type and grade of disturbance. The springs were located between 62 and 1710 m asl of altitude, in three calcareous mountain areas (Mt. Baldo, Mts. Lessini and Mt. Pasubio). They differed in conservation status (natural, moderately and highly disturbed) and belonged to five hydromorphological types (rheocrene, limnocrene, rheohelocrene, rheolimnocrene, rheohygropetric). Each spring was surveyed once, between early summer and autumn, within 50 m of the spring’s source (eucrenal). A total of 4198 chironomid larvae and pupae were sorted from 111 macroinvertebrate samples collected, belonging to five subfamilies (Tanypodinae, Diamesinae, Prodiamesinae, Orthocladiinae and Chironominae), 41 genera and 60 species/groups of species, and three juveniles taxa. As expected, Orthocladiinae accounted for a large part of specimens (88%) and species (74%), with Tvetenia calvescens/bavarica as the most frequent and abundant taxon, shared by pristine and disturbed springs and by all spring types. Most taxa were found in few sites, and frequencies declined gradually for most wider distributed species. A high number (74%) of rare (= present in less than 10% of sites) taxa were found and from one to 23 taxa were identified per spring. Maximum richness occurred in moderately disturbed (Shannon-H = 1.29±0.60) springs, located at medium-high altitude (385-1266 m asl), according to the intermediate disturbance hypothesis. Even the evenness (Equitability-J) was higher as average in these springs. A Cluster Analysis run on Bray-Curtis similarity index highlighted a high similarity i) between the chironomid assemblages of moderately disturbed and natural springs (44 species in each spring group, with 29 species in common), and ii) between rheocrene and rheohelocrene types, thus the springs with the highest microhabitat heterogeneity. High individuality of springs was revealed, and new information about non-biting midges autecology provided. The utility of chironomids as bioindicators of water quality and ecological state of springs was confirmed, with some species e associated with high disturbance level (e.g., Polypedilum nubeculosum gr. to water intake works) and others with pristine conditions (e.g., Pseudodiamesa branickii)