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Freshwater systems on remote oceanic islands are particularly vulnerable to biological invasions. The case of freshwater ecosystems in the Azores Archipelago is especially relevant considering the islands’ youth and remoteness, and low natural connectivity. This study presents a review of the introduction and presence of non-indigenous freshwater species in the Azores, retrieved from various historical records, paleoenvironmental reconstructions, published records, and field data from two decades of the Water Framework Directive (WFD) monitoring programs. At least 132 non-indigenous freshwater species have successfully established in the Azores, belonging to several taxonomic groups: cyanobacteria (10), synurophytes (1), desmids (1), diatoms (20), plants (41), invertebrates (45), amphibia (2), and fishes (12). Intentional and accidental introductions have been occurring since the establishment of the first human settlers on the archipelago, impacting freshwater ecosystems. The first reported introductions in the Azores were intentional fish stocking in some lakes. Non-deliberate introductions have recently increased through transport-contaminants (51%) associated with the aquarium trade or agricultural products. In the Azores, the highest number of non-indigenous species occur on the largest and most populated island, São Miguel Island (116), followed by Flores (68). Plants constitute the most representative group of introduced species on all islands, but invertebrates, diatoms, and fishes are also well established on most islands. Among invertebrates, non-indigenous arthropods are the most well-established group on all islands except on the smallest Corvo Island. Many non-indigenous species will likely benefit from climate change and magnified by globalization that increases the probability of the movement of tropical and subtropical species to the Azores. Present trends in international trade, importations, and enhanced connectivity of the archipelago by increasing flights and shipping will probably promote the arrival of new species. Augmented connectivity among islands is likely to improve non-indigenous species dispersal within the archipelago as accidental transportation seems to be an essential pathway for non-indigenous freshwater species already present in the Azores.

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Seabirds have evolved several life-history characteristics to help buffer environmental stochasticity. However, particularly during the breeding season, seabirds may be affected by reductions in prey availability and localised oceanographic conditions caused by variations in the environment. The increase in sea surface temperature, triggered by accelerated global warming, is impairing phytoplankton production of omega-3 fatty acids (FA). Here, we assessed the ecological role of omega-3 FA on chick development and subsequently on breeders’ foraging behaviour in two closely related shearwaters species foraging in contrasting marine environments. We supplemented chicks with omega-3 FA pills or with control placebo pills and monitored chick growth, chick health status and breeders’ at-sea foraging behaviour using global positioning system (GPS) devices. We found that omega-3 chick supplementation reduced the 95% kernel utilization distribution of Cape Verde shearwaters’ short trips, but overall breeders kept a similar foraging pattern between treatments, potentially influenced by predictable prey patches off the West African coast. In contrast, for Cory's shearwaters, the parents of the omega-3 group greatly reduced the foraging effort. This suggests that the proximity to productive prey patches around the colony may help birds to adjust their effort and, therefore, energy expenditure, to changes in the development of their offspring, as driven by their nutritional status. Overall, our results suggest a link between a chick diet enriched in omega-3 FA and parents’ foraging effort, providing insight into their ability to cope with a changing and increasingly stochastic marine environment.