Sirvi Autor "Ercoli, Fabio" järgi

Nüüd näidatakse 1 - 15 15

Behavioural responses of invasive (Gmelinoides faciatus) and native (Gammarus lacustris) amphipods to predators on different bottom substrates : [poster]
(Estonian University of Life Sciences, 2023) Teesalu, Paul; Ercoli, Fabio; Tuvikene, Arvo
The amphipod Gmelinoides fasciatus has invaded and established in numerous large lakes in Eurasia and, in the process, has displaced the native amphipod, Gammarus lacustris. In Lake Peipsi, G. fasciatus dominates the shoreline macroinvertebrate fauna, forming up to 99% of macroinvertebrate individuals (Fig. 1). The mechanism behind its invasion success is unclear and remains an important topic for invasion ecology. In order to determine if different bottom substrates and predator avoidance behaviour contribute to the invasion success of G. fasciatus we conducted two laboratory experiments.
Behavioural responses of invasive (Gmelinoides fasciatus) and native (Gammarus lacustris) amphipods to predators on different bottom substrates
(Springer Nature, 2023) Teesalu, Paul; Ercoli, Fabio; Tuvikene, Arvo
The amphipod Gmelinoides fasciatus has invaded and established in numerous large lakes in Eurasia and, in the process, has displaced the native amphipod, Gammarus lacustris. The mechanism behind its invasion success is unclear and remains an important topic for invasion ecology. Three labo- ratory experiments were conducted to determine if superior predator avoidance and different types of bottom substrate could be important factors contrib- uting to the invasion success of G. fasciatus. Our results indicate that, on gravel and sand substrates, G. fasciatus exhibited superior digging behaviour to avoid predation by fishes (perch and common roach), contrary to G. lacustris. On sandy substrate, only 9% of G. fasciatus individuals were consumed, whereas G. lacustris were consumed much more intensively at 74%. In addition, G. fasciatus exhibited a more sub- stantial reduction in activity, where the time spent in motion reduced from 37.6 to 20.8% compared to G. lacustris (from 21.8 to 17.4%) when in the presence of predatory fish kairomones. G. fasciatus movement speed was also reduced in the presence of kairomones (from 57.1 to 39.3 mm/s). However, the presence of kairomones had little effect on digging behaviour of G. fasciatus. G. fasciatus consistently demonstrated superior predator avoidance abilities over G. lacus- tris, suggesting that this mechanism might play an important role in the invasion success of G. fasciatus.
The crayfish distribution, feeding plasticity, seasonal isotopic variation and trophic role across ontogeny and habitat in a canyon-shaped reservoir
(Springer, 2020) Veselý, Lukáš; Ercoli, Fabio; Ruokonen, Timo; Bláha, Martin; Kubec, Jan; Buřič, Miloš; Hämäläinen, Heikki; Kouba, Antonín; Chair of Hydrobiology and Fishery, Institute of Agricultural and Environmental Sciences
Man-made reservoirs are important fresh-water ecosystems as they are globally common and share features of both standing and running waters. In streams and lakes, crayfish are an important component of freshwater ecosystems due to their habitat- modifying behaviour, substantial size, omnivorous feeding and often high abundance; however, their trophic role in reservoirs is not known. We evaluated the distribution and diet of noble crayfish (Astacus astacus) in the canyon-shaped, oligotrophic Nýrsko reservoir in West Bohemia region, Czech Republic. Using stable isotope analysis, we quantified the trophic level of all major components of the reservoir food web and investigated seasonal isotopic variation and how the trophic role of noble crayfish varied with habitat and ontogeny. Crayfish were an important food source for both predatory and omnivorous fish and consumed food sources from multiple trophic levels, including detritus, algae, zoobenthos and other crayfish. Throughout ontogeny, crayfish had similar levels of carnivory, but cannibalism was more prevalent in adult crayfish, while juveniles and sub-adults fed more on other zoobenthos. Moreover, crayfish had high feeding plasticity in time, as the relative importance of dominant food sources varied with season. Their feeding plasticity was especially evident in crayfish populations from different habitats, which adapted their feeding strategy to local resources. In addition, pelagic source usage increased with the depth as detritus and algae usage decreased. Proportion of females increased with the depth, while population density showed a unimodal response to the depth gradient. These findings indicate that crayfish are indeed ecologically important species with both direct and indirect roles in the trophic web of this reservoir ecosystem.
Diet and trophic niche of the invasive signal crayfish in the first invaded Italian stream ecosystem
(Nature, 2021) Ercoli, Fabio; Ghia, Daniela; Gruppuso, Laura; Fea, Gianluca; Bo, Tiziano; Ruokonen, Timo J.
The occurrence of the signal crayfsh Pacifastacus leniusculus in the Valla Stream was the frst established population of this invasive species recorded in an Italian stream ecosystem. We evaluated the seasonality of diet and trophic niche of invasive signal crayfsh in order to estimate the ecological role and efects on native communities of the stream ecosystem. We studied the diferences in food source use between sexes, life stages and seasons using carbon and nitrogen stable isotope analyses. To supplement stable isotope analyses, we evaluated food source usage using traditional stomach content analysis. We tested the hypothesis that juveniles have a diferent diet, showing diferent trophic niches, compared to adults. Results indicated that signal crayfsh adult and juvenile diets mainly rely on macroinvertebrates and periphyton in summer, shifting to mostly periphyton in autumn. Although the two age classes occupied an equivalent trophic niche, juveniles showed slightly diferent carbon isotope values, suggesting a somewhat ontogenetic shift consistent among seasons. No signifcant diferences were found in adult and juvenile diets between summer and autumn seasons. Our fndings suggest that signal crayfsh juveniles and adults exhibited seasonal feeding habits, probably due to ecological behaviour rather than food resource availability, and that both are likely to impose similar efects on macroinvertebrate communities in this and similar stream ecosystems
Differing trophic niches of three French stygobionts and their implications for conservation of endemic stygofauna
(Wiley, 2019) Ercoli, Fabio; Lefebvre, François; Delangle, Marjorie; Godé, Nil; Caillon, Michel; Raimond, Roland; Souty-Grosset, Catherine; Institute of Agricultural and Environmental Sciences. Chair of Hydrobiology and Fishery
1. Groundwater ecosystems represent the greatest proportion of unfrozen freshwa- ter on Earth and harbour high numbers of rare taxa with restricted distributions. Stygofaunal abundance, species richness, and ecology play essential roles in groundwater ecosystem services and functioning, as well as providing an impor- tant contribution to global biodiversity. However, as global depletion and contam- ination of groundwater pose serious and often irreversible threats to stygofauna, more information is urgently needed about the ecology of rare groundwater spe- cies to guide effective strategies for their conservation or restoration. 2. In this study, analyses of carbon and nitrogen stable isotopes were used to com- pare and evaluate trophic niches and diets of a vulnerable stygobiont isopod, Gallasellus heilyi living in sympatry in French groundwater ecosystems with the isopod Caecosphaeroma burgundum and the amphipod Niphargus ladmiraulti. 3. Stable isotope results showed trophic niche partitioning among the three sty- gobiont species and indicated that G. heilyi and C. burgundum occupy the role of primary consumers and N. ladmiraulti that of predator. Moreover, although G. heilyi and C. burgundum were shown to rely on the same food sources, indicat- ing similar diets, and their trophic niches did not overlap, suggesting trophic specialization. 4. The results suggest that detritus (i.e. decaying organic material) is an important food source for G. heilyi, and its availability could determine the survival of this endangered species. As a practical conservation measure for G. heilyi and the whole stygofauna community, we suggest reconnecting surface and subterranean ecosystems, as they probably were before natural sinks and many wells were filled up or closed.
Generalist invasion in a complex lake food web
(Wiley, 2023) Kuparinen, Anna; Uusi-Heikkilä, Silva; Perälä, Tommi; Ercoli, Fabio; Eloranta, Antti P.; Cremona, Fabien; Nõges, Peeter; Laas, Alo; Nõges, Tiina; Chair of Hydrobiology and Fishery
Invasive species constitute a threat not only to native populations but also to the structure and functioning of entire food webs. Despite being considered as a global problem, only a small number of studies have quantitatively predicted the food web-level consequences of invasions. Here, we use an allometric trophic network model parameterized using empirical data on species body masses and feeding interactions to predict the effects of a possible invasion of Amur sleeper (Perccottus glenii), on a well-studied lake ecosystem. We show that the modeled establishment of Amur sleeper decreased the biomasses o ftop predator fishes by about 10%–19%. These reductions were largely explained by increased larval competition for food and Amur sleeper predation on fish larvae. In contrast, biomasses of less valued fish of lower trophic positions increased by about 0.4%–9% owing to reduced predation pressure by top piscivores. The predicted impact of Amur sleeper establishment on the biomasses of native fish species vastly exceeded the impacts of current-dayfishing pressures.
Generalist invasion in a complex lake food web : [presentation]
(University of Jyväskylä, 2023) Kuparinen, Anna; Uusi-Heikkilä, Silvia; Perälä, Tommi; Ercoli, Fabio; Eloranta, Antti; Cremona, Fabien; Nõges, Peeter; Laas, Alo; Nõges, Tiina
The presentation took place at the 11th International Shallow Lakes Conference.
Genome analysis of the monoclonal marbled crayfish reveals genetic separation over a short evolutionary timescale
(Springer Nature, 2021) Maiakovska, Olena; Andriantsoa, Ranja; Tönges, Sina; Legrand, Carine; Gutekunst, Julian; Hanna, Katharina; Pârvulescu, Lucian; Novitsky, Roman; Weiperth, András; Sciberras, Arnold; Deidun, Alan; Ercoli, Fabio; Kouba, Antonin; Lyko, Frank; Chair of Hydrobiology and Fisheries
The marbled crayfish (Procambarus virginalis) represents a very recently evolved parthenogenetic freshwater crayfish species that has invaded diverse habitats in Europe and in Madagascar. However, population genetic analyses have been hindered by the homogeneous genetic structure of the population and the lack of suitable tools for data analysis. We have used whole-genome sequencing to characterize reference specimens from various known wild populations. In parallel, we established a whole-genome sequencing data analysis pipeline for the population genetic analysis of nearly monoclonal genomes. Our results provide evidence for systematic genetic differences between geographically separated populations and illustrate the emerging differentiation of the marbled crayfish genome. We also used mark-recapture population size estimation in combination with genetic data to model the growth pattern of marbled crayfish populations. Our findings uncover evolutionary dynamics in the marbled crayfish genome over a very short evolutionary timescale and identify the rapid growth of marbled crayfish populations as an important factor for ecological monitoring.
Introduced alien signal crayfish (Pacifastacus leniusculus) in Finland - uncontrollable expansion despite numerous crayfisheries strategies
(EDP Sciences, 2018) Ruokonen, Timo J.; Sjövik, Rosanna; Erkamo, Esa; Tulonen, Jouni; Ercoli, Fabio; Kokko, Harri; Jussila, Japo; Centre for Limnology. Institute of Agricultural and Environmental Sciences
In Finland, massive signal crayfish introductions started towards the end of 1980s, with an estimated total of 2.2 million signal crayfish been stocked before year 2016. During that period, Finnish fisheries authorities have implemented three national management strategies setting guidelines for the crayfish introductions. The main aims of the strategies have been conservation of native noble crayfish stocks and a controlled spreading of the alien signal crayfish within a designated region. In this study, we report the current distribution of signal crayfish in Finland in comparison to the guidelines set in these three national strategies. The present distribution area of the signal crayfish covers most of the Southern Finland. The signal crayfish has been introduced with a stocking permits to over 480 water bodies. In addition, there have been numerous stockings without permits, which are often next to the region designated for signal crayfish. Based on the results, we conclude that crayfisheries strategies adopted in Finland have only had limited effect on the spread of signal crayfish. We presume that main causes for the uncontrolled spreading of the signal crayfish in Finland have been lack of strict official supervision and general lack of awareness about the risks associated with the alien species spreading.
Niche partitioning of invasive Amur sleeper (Perccottus glenii) amongst native fish communities in three different freshwater ecosystems
(Pensoft Publishers, 2024) Ercoli, Fabio; Kiljunen, Mikko; Teesalu, Paul; Tuvikene, Arvo; Tambets, Meelis; Kärgenberg, Einar; Nõges, Tiina
The invasive fish, Amur sleeper, poses a significant and growing threat to Central European freshwater ecosystems. Despite its rapid spread, the ecological implications of its invasion have been poorly explored. Recent findings confirm its presence in various Estonian freshwater systems, raising concerns about its imminent expansion into larger lakes. To better understand its potential ecological impacts, we explored the isotopic niche of the Amur sleeper in comparison with native fish species co-existing in three Estonian freshwater ecosystems. We employed carbon and nitrogen stable isotope analyses alongside gut content analyses. Our findings show that the Amur sleeper’s diet in newly-invaded Estonian water bodies predominantly comprises benthic macroinvertebrates, although it may also include fish, confirming its role as a predator in the local food web. Notably, Amur sleeper populations exhibited clear isotopic niche partitioning in three invaded ecosystems. A logistic regression model, based on stomach content analyses, revealed an ontogenetic diet shift from benthivorous to piscivorous feeding habits from small to large specimens. Amur sleeper exhibits voracious, non-selective feeding habits, which can negatively impact native freshwater communities. The ability to occupy a distinct isotopic niche, with minimal overlap with native fish populations, may reduce interspecific competition, facilitating the spread and establishment of Amur sleeper in newly-invaded habitats. Managing the spread of this invasive species thus becomes even more critical to safeguard the integrity of native aquatic ecosystems.
Parasites in sympatric populations of native and invasive freshwater bivalves
(Springer Nature, 2021) Taskinen, Jouni; Urbanska, Maria; Ercoli, Fabio; Andrzejewski, Wojciech; Ozgo, Małgorzata; Deng, Binglin; Choo, Jocelyn, M.; Riccardi, Nicoletta; Chair of Hydrobiology and Fishery, Institute of Agricultural and Environmental Sciences
An increasing threat to local, native freshwater mussels (Unionida)—an ecologically important but globally alarmingly declining group— is the invasion by exotic bivalves. The Enemy Release Hypothesis predicts that introduced species should benefit from enemy-mediated competition because they are less likely to be harmed by natural enemies, such as parasites, than their native competitors. We investigated within-site differences in parasitism between sympatric native (tot. five spp.) and invasive (tot. three spp.) bivalves in eight northern European waterbodies, which harboured totally 15 parasite taxa. In paired comparisons using within-site averages, the mean number of parasite species in the native bivalves was 2.3 times higher, and the sum of parasite prevalences 2.4 times higher, than in the invasive bivalves. This may lead to enemy-mediated compet- itive release of invaders and contribute to the success of invasive freshwater bivalves, in general. However, while the invasive clam Corbicula fluminea was completely free from parasites, parasite parameters of the other invader, Sinanodonta woodiana, were relatively high, indicating that the role of parasites can be invader-specific and urges further research. Under- standing the factors affecting success of freshwater bivalve invasions, such as parasitism, can aid invasion control and conservation of local, native (endangered) bivalves.
Strong temporal variation of consumer δ13C value in an oligotrophic reservoir is related to water level fluctuation
(Nature Portfolio, 2023) Veselý, Lukáš; Ercoli, Fabio; Ruokonen, Timo; Bláha, Martin; Duras, Jindřich; Haubrock, Phillip J.; Kainz, Martin; Hämäläinen, Heikki; Buřič, Miloš; Kouba, Antonín; Chair of Hydrobiology and Fishery
Using stable carbon and nitrogen isotope analysis (δ 13 C and δ 15 N) to assess trophic interactions in freshwater ecosystems is a well established method, providing insight into ecosystem functioning. However, the spatial and temporal variability of isotope values, driven by environmental fluctuation is poorly understood and can complicate interpretations. We investigated how the temporal variation of stable isotopes in consumers (fish, crayfish and macrozoobenthos) of a canyon-shaped oligotrophic reservoir is associated with environmental factors such as water temperature, transparency, flooded area, and water quality measures. Consumers and their putative food sources were sampled and analyzed for carbon and nitrogen stable isotopes annually, and environmental parameters were measured monthly from 2014 to 2016. Results revealed significant differences in δ 13 C and δ 15 N values in each consumer among studied years. Over the years, fish and crayfish expressed differences in δ 13 C between 3 and 5‰, whereas in zoobenthos differences were 12‰. Variability in δ 15 N was similar across all consumers (2–4‰). Moreover, results suggest that the flooded area of the reservoir was a major driver of δ 13 C stable isotope values variation in consumers, while variation in δ 15 N was not linked to any of the studied environmental factors. Bayesian mixing models further showed significant changes in the origin of detritivorous zoobenthos carbon sources (reversal shift from terrestrial detritus to algae origin) between years with low water level to years with the standard water level. Other species showed only slight differences in food source utilization among years. Our study highlights the importance of environmental factors as sources of variation in consumer’s stable isotope values which should be considered especially when studied ecosystem strongly fluctuate in some environmental factor.
Syllabuses for two Masters and PhD level courses on stable isotope applications and aquatic ecosystem modelling : D6.1
(Estonian University of Life Sciences, 2022) Ercoli, Fabio; Cremona, Fabien
Objective of work package. The main goal of WP6 is to strengthen scientific activities of early-stage researchers by improving the long-term quality of lake ecology education at the Estonian University of Life Sciences (EMU), providing new summer/winter schools, student exchange, PhD supervision, and establishment of new courses.
Trophic niches of three sympatric invasive crayfish of EU concern
(Springer, 2021) Veselý, Lukáš; Ruokonen, Timo; Weiperth, András; Kubec, Jan; Szajbert, Bettina; Guo, Wei; Ercoli, Fabio; Bláha, Martin; Buřič, Miloš; Hämäläinen, Heikki; Kouba, Antonín
The spread of non-native species results in novel and often unexpected assemblages. Using stable isotopes, we disentangled the trophic relation- ships between three invasive crayfish species at two sites of a small thermal tributary of the Bara ́t stream, Hungary. We studied Procambarus virginalis and Faxonius limosus living in sympatry in the upper section of this thermal tributary, and then an assem- blage in a lower section also containing P. clarkii. The two species in the upper section largely shared trophic niches, although P. virginalis was more carnivorous than F. limosus, which fed more on detritus and aquatic plants. In the lower section, P. clarkii had a distinctive trophic niche, being more carnivorous than the other species and also preying on other crayfish and fish. The trophic niches of the other two species shifted slightly, being narrower and more overlapping in the presence of P. clarkii. It seems that the presence of P. clarkii affects the feeding habits and trophic niches of the other two crayfish. Our results also indicate that the species have somewhat distinctive feeding niches, which suggests that the ecosystem effects of these species are likely to be at least partially additive in the shared localities.
Trophic role of marbled crayfish in a lentic freshwater ecosystem
(Regional Euro-Asian Biological Invasions Centre, 2019) Lipták, Boris; Veselý, Lukáš; Ercoli, Fabio; Bláha, Martin; Buřič, Miloš; Ruokonen, Timo J.; Kouba, Antonín; Institute of Agricultural and Environmental Sciences. Chair of Hydrobiology and Fishery
Species’ introductions may cause severe adverse effects on freshwater ecosystems and their biota. The marbled crayfish, Procambarus virginalis Lyko, 2017, is an invasive parthenogenetically reproducing crayfish with rapid reproduction, maturation and tolerance to a wide range of environmental conditions, which was introduced to many sites across Europe during the last decade. Due to its recent speciation and limited number of field studies, the knowledge of trophic interactions of the marbled crayfish in freshwater food webs is scarce. An invaded area located in Central Europe was studied to identify the marbled crayfish food web interactions using analysis of carbon 13 C and nitrogen 15N isotopes. This study brings the first insight into the trophic ecology of marbled crayfish in lentic freshwater ecosystems. Algae and detritus were identified as the most important food sources for the marbled crayfish, while zoobenthos and macrophytes were less important. Moreover, the marbled crayfish was found to be an important food source for top fish predators, but marginal for omnivorous fish. Being able to utilize energy from the bottom of the trophic food web, the marbled crayfish may have important roles in the ecosystem, transferring energy to higher trophic levels. It processes allochthonous and autochthonous matter in the ecosystem, thus being a competitor to other organisms with similar food preferences and impacting zoobenthos, algae and macrophytes through predation or direct consumption. To sum up, the marbled crayfish has a strong ability to utilize food sources from different trophic levels, and, thanks to its life history, can be a highly adaptable invader.

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