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Sirvi Autor "Ercoli, Fabio (advisor)" järgi

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  • Pisipilt
    Kirje
    Assessing behavioural traits and ecological impacts of invasive crayfish species in freshwater ecosystem
    (Estonian University of Life Sciences, 2024) Ghia, Daniela; Sacchi, Roberto (advisor); Ercoli, Fabio (advisor); Institute of Agricultural and Environmental Sciences; Department of Earth and Environmental Sciences, University of Pavia; Maguire, Ivana (opponent); Kozák, Pavel (opponent)
    ABSTRACT. Biological invasions occur when species spread to new areas, causing ecological, economic, and social problems. Invasive species can be found in various ecosystems, but freshwater ecosystems are particularly vulnerable due to human activities and environmental changes. It has been forecasted that the invasion of alien species will increase by up to 36% by 2050, particularly in Europe. Among these invaders, crayfish are expected to see significant increases globally, representing major threats. These large freshwater invertebrates have attracted the attention of freshwater biologists and ecologists because of their ability to travel long distances, high reproductive rates, and adaptability. To better manage invasive species and conserve native ones, it's crucial to understand their behaviour and impacts on ecosystems. This research study has focused on understanding the behaviour of invasive crayfish and their impacts on freshwater ecosystems. Results highlighted the high adaptability of signal crayfish, which can vary their diet by season and age and, when coexist with native crayfish, they adjust their feeding habits, likely to reduce competition. The study also revealed that signal crayfish individuals coexisting with native crayfish at the invasion front are stronger than those living alone, suggesting a more successful invasion. It has also been found that invasive crayfish have a remarkable ability to disperse over land during droughts, showing their resilience and potential to spread. Additionally, experiments on their reproductive behaviour and the effects of removing female reproductive parts showed that this method could effectively reduce their reproductive capacity. These findings show the importance of considering behavioural traits in managing invasive species. Implementing control programs for invasive crayfish is crucial to preserving biodiversity and maintaining healthy freshwater ecosystems worldwide.
  • Pisipilt
    Kirje
    Non-native species invasion strategies and effects on freshwater native communities
    (Estonian University of Life Sciences, 2025) Teesalu, Paul; Ercoli, Fabio (advisor); Tuvikene, Arvo (advisor); Institute of Agricultural and Environmental Sciences; Tricarico, Elena (opponent)
    ABSTRACT. The spread of invasive species has been forecasted to increase, particularly in freshwater ecosystems due to anthropogenic and environmental changes taking place at increasing rates. Invasive species generally adapt quickly to new environments, have high reproductive rates and can tolerate a wide range of conditions. This thesis studied three invasive species in the Narva reservoir area and found that their success is linked to dietary flexibility, behaviour, and tolerance to temperature changes. The Amur sleeper fish (Percottus glenii) can inhabit various waterbodies, for example, we found it in a warm-water channel, a large reservoir and a small pond. The Amur sleeper demonstrated great dietary plasticity, or the ability to consume a wide range of prey items. As Amur sleeper individuals grew, their diet shifted from a benthivorous diet to a piscivorous diet. The small amphipod Gmelinoides fasciatus, which has outcompeted and displaced native gammarid Gammarus lacustris in Lake Peipsi, exhibits superior predator avoidance and shows a more pronounced behavioural response to predators than its native counterpart, increasing its survivability. Marbled crayfish (Procambarus fallax virginalis) can shift from a protein rich macroinvertebrate based diet to a macrophyte based diet, indicating great dietary plasticity. Additionally, marbled crayfish, despite being considered a warm-water species, could withstand a wide range of water temperatures ranging from 0-30 °C over an extended period at our study site. During the implementation of invasive species management programs, it is important to consider their environmental tolerance, dietary adaptability and behavioural traits. As conditions change in our freshwater lakes and reservoirs, it is likely that invasive species will continue to be a problem, highlighting the need to understand and manage their spread to protect native freshwater ecosystems.