2026/06/04 by Laura Jiménez Liebanas, Vanessa Céspedes, Félix Picazo +2 · 1 voice · 1 citation
Environmental Science · #Aquatic Invertebrate Ecology and Behavior #Marine Ecology and Invasive Species #Aquatic Ecosystems and Phytoplankton Dynamics
paper · doi:10.1016/j.ecolind.2026.114937
openalex publication_date 2026/06/04 · openalex created_date 2026/06/04 · openalex updated_date 2026/07/29
Invasive species are a major threat to global biodiversity, yet their functional impacts on ecosystems are less studied than dispersal and establishment. These impacts are multifaceted, cascading through ecosystems via trophic interactions and indirect habitat alteration, and may intensify through interactions with other invaders. This study investigated the impacts of apple snail ( Pomacea maculata ) and blue crab ( Callinectes sapidus ) on habitat quality, and the taxonomic and functional composition of macroinvertebrate communities in the Lower Ebro River, Spain. A set of a priori hypotheses about expected effects were tested, providing a framework for future research in other invaded systems. Results show that both invaders are associated with degraded habitat quality. Suspended solids were twice as high and chlorophyll- a fourfold higher in invaded than control habitats, indicating intensified nutrient mobilization. These changes cascaded to impact community structure. While taxonomic richness, abundance, and diversity remained stable, composition shifted. Sensitive taxa like Ephemeroptera and Trichoptera declined, replaced by tolerant taxa including Coleoptera, Odonata, and Gastropoda. Functional indicators revealed strong homogenization in invaded sites, with reduced functional richness and diversity. Traits like small body size, resistance forms, and predatory feeding were more prevalent in invaded habitats. Impacts intensified where both invaders co-occurred, supporting the invasional meltdown hypothesis. This is one of the first studies assessing ecological consequences for two co-occurring invasive species, from distinct trophic levels without shared evolutionary history. We conclude that functional indicators are more sensitive than taxonomic metrics and provide mechanistic information about the impacts of invasive species in aquatic ecosystems.