Has the recolonization of the Po Plain begun? Updates regarding the presence of the Eurasian otter (Lutra lutra) in north-eastern Italy

Widespread in Italy in the early 1900s, the Eurasian otter subsequently underwent a dramatic decline that led to its local extinction in many administrative regions, with the exception of a small residual nucleus in southern Italy. For a few years now, the Austrian and Slovenian populations adjacent to north-eastern Italy have been increasing sharply, leading to a recolonization of the area by the species. During 2020, in Friuli Venezia Giulia, surveys of signs of presence were carried out in 48 grid cells (10 x 10 km) to update information on the species’ local distribution. The following monitoring methods were used: monitoring beneath bridges combined with transects along water courses. 17 grid cells tested positive for the presence of the species, and currently, the otter appears widely distributed in Friuli Venezia Giulia along the main waterways of the Eastern Alps and Prealps, and in some areas overlooking the plain of the Tagliamento and the transborder Isonzo-Soča basin, both included in the Po plain. These constitute the first observations of the species for more than 50 years. Compared to previous studies, 13 new grid cells involving the presence of otters were identified, including in lowland areas, suggesting a progressive expansion from the mountain ranges towards the Po-Venetian Plain. This represents, a spur to expand research and implement new studies to improve levels of knowledge about and the consequent protection of the species. Finally, the integration of transects along riverbanks to monitoring beneath bridges, allowed us both to collect numerous observation and to compare our results with previous studies

Energy Densities of Brown Trout (Salmo trutta) and Its Main Prey Items in an Alpine Stream of the Slizza Basin (Northwest Italy)

ABSTRACT In the present study, energy densities of 80 adult brown trout (Salmo trutta), seasonally sampled in an alpine stream in the eastern Alps and energy densities of their main prey items, were determined. The energy density (J/g wet mass) and dry weight content (%) of fish were highly correlated (p<0.00 1) and averaged 5, 611.6 ± 857.9 J/g wet mass and 25.3 ± 2.1% dry weight, respectively. Energy density values were significantly higher in fish sampled in spring than in other seasons. No major changes in the energy content were observed due to age or sex. Macroinvertebrates. particularly Ephemeroptera and Diptera, were the major food source of brown trout in the sampled area. Their gross energy content varied within a wide range of values (1, 654–5, 110 J/g wet weight), depending on the taxa and family or genus within a given taxon

Metabolic rate and climate change across latitudes: Evidence of mass-dependent responses in aquatic amphipods

Predictions of individual responses to climate change are often based on the assumption that temperature affects individuals’ metabolism independently of their body mass. However, empirical evidence indicates that interactive effects exist. Here, we investigated the response of individual Standard Metabolic Rate (SMR) to annual temperature range and forecasted temperature rises of 0.6-1.2°C above the current maxima, under the conservative climate change scenario IPCC-RCP2.6. As a model organism we used the amphipod Gammarus insensibilis, collected across latitudes along the western coast of the Adriatic Sea down to the southernmost limit of the species’ distributional range, with individuals varying in body mass (0.4-13.57mg). Overall, we found that the effect of temperature on SMR is mass-dependent. Within the annual temperature range, the mass-specific SMR of small/young individuals increased with temperature at a greater rate (activation energy: E=0.48 eV) than large/old ones (E=0.29 eV), with a higher metabolic level for high-latitude than low-latitude populations. However, under the forecasted climate conditions, the large individuals’ mass-specific SMR responded differently across latitudes. Unlike the higher-latitude population, whose mass-specific SMR increased in response to the forecasted climate change across all size classes, in the lower-latitude populations, this increase was not seen in large individuals. The larger/older conspecifics at lower latitudes could therefore be the first to experience the negative impacts of warming on metabolism-related processes. Although the ecological collapse of such a basic trophic level (aquatic amphipods) due to climate change would have profound consequences for population ecology, the risk is significantly mitigated by phenotypic and genotypic adaptation

First data on the reproduction of the Vagrant Emperor Anax ephippiger in North-Eastern Italy, Friuli-Venezia Giulia Region (Odonata aeshnidae)

Riassunto: Primi dati sulla riproduzione di Imperatore Migrante anax ephippiger in Friuli-Venzia Giulia, Nord-Est d\u2019Italia. Anax ephippiger (burmeister, 1839) \ue8 una libellula migratrice che proviene dall\u2019africa e dal Medio Oriente e di cui in Europa sono conosciute solo generazioni estive e non vi sono evidenze di larve svernanti. Durante l\u2019agosto 2010 in Friuli-Venezia Giulia, Italia nord-orientale, \ue8 stato trovato un sito riproduttivo per questa specie, prima prova di riproduzione per la specie in Nord-Est d\u2019Italia. Nello stagno in cui \ue8 stata accertata la riproduzione, con lo scopo di incrementare le conoscenze ecologiche sulla specie e delinearne l\u2019habitat di riproduzione, sono stati rilevati: la comunit\ue0 a odonati (adulti ed esuvie), la vegetazione e i parametri chimico-fisici dell\u2019acqua (compresa la salinit\ue0 dell\u2019acqua, essendo lo stagno in comunicazione con il mare e non essendo disponibili informazioni dettagliate rispetto alla tolleranza delle larve a tale parametro). Questo nuovo ritrovamento faunistico, corredato da dati ecologici, si inserisce all\u2019interno di una pi\uf9 vasta rete di avvistamenti per la specie, rappresentando la prova dell\u2019ampliamento verso Nord dell\u2019areale di A. ephippiger e avvalorando la tesi della sensibilit\ue0 degli odonati al riscaldamento globale. Abstract: The Vagrant Emperor, Anax ephippiger (burmeister, 1839), is a migrant dragonfly species from africa and Middle East; in Europe only summer generation are known, without evidence of overwintering larvae. In august 2010 a reproductive breeding site for this species was found in the in Friuli-Venezia Giulia Region (north-eastern Italy). This discovery represents the first proof of reproduction for the species in north-eastern Italy. With the aim of increasing the knowledge on the species requirements, a study to delineate the emerging habitat was conducted: dragonfly community (adult and exuviae), vegetation, chemical and physical water parameters were sampled. This yielded data about larval tolerance toward salinity. This new data proves a northward move for the species, which may also have been facilitated by global warming

Biology and distribution of Danube barbel (Barbus balcanicus) (Osteichthyes: Cyprinidae) at the Northwestern limit of its range

Presence of Danube barbel Barbus balcanicus was investigated at the westernmost portion of its distribution area (Italian portion of the Isonzo River Basin). Genetic analyses carried out on specimens collected in different watercourses confirmed B. balcanicus presence in the same locations where Barbus caninus was erroneously classified in the past. More precisely, 4 Cyt b haplotypes belonging to the Balkanic species were described, three of which were evidenced for the first time. Analysis of meristic characters also confirmed genetic results and completed the taxonomical assessment. At the same time, a target population was studied to deepen knowledge about the species ecology. In this case, 120 specimens belonging to five age classes (from 0+ to 4+) were collected with monthly frequency in Barbucina Creek, representing the model watercourse inhabited by the species in the study area. Regression between total weight (W) and standard length (SL) did not differ significantly between males and females, therefore not displaying sexual dimorphism. SL values showed wide ranges, often overlapping among age classes. Mean condition factor (Kmean) decreased significantly with growth and age, as small individuals were in better nutritional condition. From an ecological point of view, biometric parameters seemed to be affected by habitat conditions and, specifically, to the limited space of the creeks, rather than by trophic conditions. Finally, trends of gonadosomatic index (GSI) showed that B. balcanicus reproductive period stretches between April and late May/early June. Results indicated that sexual maturity is reached at 1+ age, corresponding to a mean standard length equal to 5.50 ± 0.66 for female and 5.71 ± 0.53 for male breeders. In conclusion, experimental results highlighted the presence and adaptability of this "forgotten" species of the Italian fish fauna, which certainly will deserve attention in a future amendment of the Italian IUCN Red List of vertebrates

Accumulation of As, Cd, Pb, and Zn in sediment, chironomids and fish from a high-mountain lake: First insights from the Carnic Alps

Though mountain lakes are generally much less influenced by human activities than other habitats, anthropogenic threats can still alter their natural condition. Amajor source of global environmental pollution inmountain ecosystems is trace element contamination. For this studywe investigated for the first time the accumulation of As, Cd, Pb, and Zn in sediment, Diptera Chironomidae (prey), and bullhead Cottus gobio (predator) in a typical high-mountain lake (Dimon Lake) in the Carnic Alps. Significant differences in trace element levels were observed between sediment, Diptera Chironomidae, and C. gobio liver and muscle samples (Kruskal-Wallis test; p b .03 for all elements). As and Pb levels were highest in sediment, Cd and Zn levels were highest in Diptera Chironomidae, and the lowest values for all elementswere measured in C. gobio muscle and liver. Bioaccumulation factor values weremuch higher in Diptera Chironomidae than fish muscle and liver, with the highest values recorded for Cd (5.16) and Zn (4.37). Trophic transfer factor valueswere very lowfor all elements in fish muscle and liver, suggesting a biodilution effect along the food chain. Further studies are needed to expand on these first findings that provide useful insights to inform environmental monitoring and policy in remote high-mountain lakes

Aspetti della biologia ed analisi del ciclo riproduttivo di Gobio benacensis (Pollini, 1816) nel Nordest Italia

Il presente studio si propone di approfondire la biologia ed il ciclo riproduttivo del gobione italiano (Gobio benacensis), specie endemica a corologia cisalpina inclusa nella categoria \u201cEndangered\u201d (EN) della lista rossa IUCN, con l\u2019intento di fornire informazioni utili a redigere corretti piani gestionali volti alla conservazione della specie. Le indagini sono state condotte in un corso d\u2019acqua del Bacino del Fiume Isonzo (Torrente Reca, Nordest Italia) ed hanno riguardato 86 esemplari catturati nell\u2019aprile 2016 al fine di definirne la consistenza e la struttura della popolazione e 77 esemplari, catturati mensilmente e bimestralmente tra aprile 2016 e febbraio 2017, per la definizione del ciclo riproduttivo. Le curve di regressione del peso sulla lunghezza totale per i maschi (W=0,1253TL2,8770) e per le femmine (W=0,1555TL2,7554), confrontate mediante ANCOVA, non hanno denunciato differenze significative. I valori medi \ub1 deviazione standard dell\u2019indice gonadosomatico GSI per i maschi sono compresi tra 0,61\ub10,49 e 1,75\ub10,58, mentre per le femmine tra 1,02\ub10,88 e 14,15\ub12,80. L\u2019indice epatosomatico HSI ha denunciato range compresi tra 0,05\ub10,02 e 2,68\ub11,26 e tra 0,25\ub10,19 e 1,75\ub10,58 rispettivamente per i maschi e per le femmine. Le analisi istologiche di ovari e testicoli, analizzati per la prima volta nella specie, hanno permesso di identificare gli stadi di maturazione, che unitamente all\u2019analisi del GSI indicano che la specie depone le uova a pi\uf9 riprese durante il periodo riproduttivo compreso tra aprile e giugno. Nei maschi \ue8 stata, tuttavia, evidenziata una prolungata attivit\ue0 riproduttiva che si protrae fino al mese di agosto