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Defining non-indigenous fish assemblage types in Mediterranean rivers: Network analysis and management implications
Nicholas Koutsikos1, Leonidas Vardakas2, Theocharis Vavalidis2
1Hellenic Centre for Marine Research, Institute of Marine Biological Resources and Inland Waters, Anavissos, 19013, Attica, Greece; Department of Environment, University of the Aegean, Mytilene, 81100, Greece.
Journal of Environmental Management
|November 6, 2020
Summary
This study introduces a new framework to classify non-indigenous fish assemblages (FATs) in Mediterranean rivers. This helps in early detection and designing targeted management strategies for invasive fish species.
Area of Science:
- Ecology
- Environmental Management
- Invasive Species Biology
Background:
- Managing non-indigenous fish species (NIFS) in freshwater ecosystems presents significant challenges.
- Current management strategies often lack specificity for different invasive fish assemblages.
- Understanding the factors influencing NIFS distribution is crucial for effective control.
Purpose of the Study:
- To develop and apply a classification framework for non-indigenous fish assemblage types (FATs) in Mediterranean riverine ecosystems.
- To identify the environmental factors (regional, local, biotic, abiotic) linked to FAT distribution.
- To inform pre-invasion screening and post-invasion management of NIFS.
Main Methods:
- Network analysis of 393 samples from 51 Greek river basins to extract NIFS community data.
- Multivariate ordination analysis to determine factors influencing FAT structure and distribution.
- Alluvial diagrams used to visualize associations across spatial scales.
Main Results:
- Five distinct FATs were identified, characterized by key indicator species (e.g., Gambusia-FAT, Carp-FAT).
- FATs exhibited spatial variation, reflecting differences in community structure, habitat preferences, and life-history traits.
- Alien FATs were prevalent in large, transboundary rivers; Translocated and Salmonids FATs occurred in depauperate, biodiversity-rich ecoregions.
Conclusions:
- The developed FAT framework aids in identifying conservation priorities and designing type-specific management actions for NIFS.
- This approach can guide the protection of high-priority water bodies against future invasions.
- Understanding FATs is essential for proactive and effective invasive species management in freshwater systems.
