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Organisms determine environmental quality using their senses and personal experience (personal information) but can also use byproducts of other individuals' activities (i.e. public information). The ability to use public information originating from both con- and heterospecifics gives an advantage over individuals relying only on personal information or conspecific cues. The role of public information in invasion ecology is of high concern, as any differences in this aspect between alien and native species may determine the success of the former. Here, we studied 2 pairs of sympatric invasive and native demersal fish species (racer goby Babka gymnotrachelus /European bullhead Cottus gobio ; monkey goby Neogobius fluviatilis/ gudgeon Gobio gobio) facing 2 types of public cues (associated with antipredatory and foraging behavior). We used them as a model to check if the invaders could use public information from more sources than the natives. Both invaders and the native gudgeon used cues from con- and heterospecifics, exhibiting antipredatory behavior, while the native bullhead failed to recognize such cues from heterospecifics. The monkey goby and both native species were attracted to foraging cues from donors less likely to exert competitive pressure on the observer (i.e. native species rather than potentially more aggressive invaders). On the other hand, the racer goby appeared unable to correctly recognize heterospecific foraging cues. Our results showed that public cues can enable invaders to read threat from a wide range of individuals and to find optimal food patches, which may contribute to their invasion success. [ABSTRACT FROM AUTHOR]

In connection with the expansion of alien gobies in European waters, a question arises whether this process can be enhanced or inhibited by global warming. The gobies are of Ponto‐Caspian origin, where the climate is warmer than in invaded European areas. Therefore, they are likely to cope physiologically with climate warming better than native species. Our aim was to identify differences in metabolic traits under elevated summer temperature between the invasive gobies and their native counterparts.Using a laboratory respirometer, we compared the effect of elevated summer temperature (25 vs. 17°C) on the metabolic responses of fish in two species pairs consisting of an invasive goby versus its native counterpart from the same ecological guild: the invasive racer goby Babka gymnotrachelus versus native European bullhead Cottus gobio, and the invasive monkey goby Neogobius fluviatilis versus native gudgeon Gobio gobio. The paired species share functional traits, including morphological characteristics, despite belonging to different fish families. After 4 weeks of acclimation, standard metabolic rate (SMR), maximum metabolic rate (MMR) and aerobic scope (AS = MMR–SMR) of the fish were determined.We found that SMR increased under elevated temperature irrespective of species, yet it was always lower in the gobies than in natives. The MMR of the racer goby was lower than that of the bullhead across all temperatures, whereas no differences in MMR were found between the gudgeon and monkey goby. On the one hand, the elevated temperature did not affect the AS of the racer goby and bullhead. However, the AS of the racer goby was consistently lower than that of the bullhead across all temperatures. On the other, elevated temperature caused a decrease in AS in both the monkey goby and gudgeon. However, this temperature‐induced change in AS was higher in the gudgeon than in the monkey goby.In terms of AS, the invaders did not always outperform the natives at higher temperatures. However, the invaders had lower living costs by maintaining a lower SMR. These results suggest that invasion by gobies may be facilitated by global warming, which is likely to increase their occurrence and effect on local fish communities in freshwater temperate systems. [ABSTRACT FROM AUTHOR]

1. Ecosystem engineering freshwater bivalves, burrowing in the substratum and accumulating shell deposits, transform bottom habitats. Especially the invasive Asian bivalve Sinanodonta woodiana (SW), due to its rapid growth, large size, and high fecundity, can affect benthic communities. Here, we determined its effect on habitat selection and behaviour of endangered native bivalves, Anodonta cygnea and Unio tumidus. 2. We conducted laboratory preference assays (Experiment 1: choice between two substrata) exposing the native bivalves to pure sand (control), shells (several densities on the sand surface or burrowed), or living SW. Then, we tested their locomotion and burrowing (Experiment 2) on pure sand and substrata contaminated with shells or living SW. 3. In Experiment 1, native bivalves avoided shells, but not living SW. Burrowed and larger shells were avoided compared with those on the surface and smaller ones, respectively. 4. In Experiment 2, U. tumidus exposed to SW delayed activity initiation (in response to living bivalves), increased locomotion (living bivalves, surface shells), and reduced burrowing depth (living bivalves, all shells). Anodonta cygnea exposed to SW reduced locomotion speed (living bivalves, shells), and reduced burrowing duration (burrowed shells) and depth (living bivalves, burrowed shells). 5. SW (especially shell beds) constitutes another emerging threat to native bivalves, impairing their burrowing and inducting active avoidance. As SW expands its distribution with climate warming, the range and strength of its impact is likely to increase, reducing the area available to native bivalves, exposing them to environmental dangers (due to burrowing limitation) and deteriorating physical condition (energetic resources used for excessive locomotion). [ABSTRACT FROM AUTHOR]

Globally, fish are frequently introduced beyond their native range. Some, like Ponto-Caspian gobies, are becoming invasive, achieving high colonization rates and constituting frequent prey for native predators. However, little is known about the effectiveness of antipredator behaviors of the invaders, which may shape their role in the invaded community and contribute to the invasion success. We compared antipredator behaviors of invasive gobies and native fish species after their detection by the predator, when the danger becomes direct. We studied 2 fish pairs, each consisting of an invasive and native species co-occurring in the environment and belonging to the same prey guild: (1) the racer goby Babka gymnotrachelus versus European bullhead Cottus gobio , (2) the monkey goby Neogobius fluviatilis versus gudgeon Gobio gobio , facing a naïve predator (the Eurasian perch Perca fluviatilis). We analyzed behaviors of single prey individuals (escaping, staying in shelter, and activity) and single predators (activity, searching, following, capturing, and latency to prey consumption). In the predator presence, the bullhead was less active and more often managed to escape after capture than the racer goby. The gudgeon escaped before the capture more often than the monkey goby. The predator succeeded later with the bullhead compared to racer goby, whereas no differences in ingestion time occurred between the gudgeon and monkey goby. The results suggest that, in terms of hunting effort of native predators, the invasive gobies are equivalent to or more profitable prey than their native analogs, which can facilitate the integration of the gobies into local food webs. [ABSTRACT FROM AUTHOR]

Knowledge of habitat requirements and interspecific interactions of invasive species helps predict their impact and spread. We determined the relationships within the invasive freshwater Ponto-Caspian amphipod assemblage, and their associations with macroinvertebrates in the near-shore zone of a central European lowland dam reservoir. We sampled five habitat types: bare sand at the water line, bare sand (0.2 m depth), bare sand (0.5 m depth), macrophyte-overgrown sand (1 m depth), stones (0.3 m depth) on four dates (October 2015–October 2016). Pontogammarus robustoides occurred in all habitats, Dikerogammarus villosus and Echinogammarus ischnus were limited to the stony bottom. Amphipod densities were positively associated with one another except Dikerogammarus juveniles, negatively correlated with adults. The occurrence of D. villosus, juvenile Dikerogammarus and E. ischnus was positively related to the presence of the shelter-forming bivalve Dreissena polymorpha. Pontogammarus robustoides was positively associated with sphaeriid clams and gastropods (shelters), as well as oligochaetes and chironomids (potential prey items). Dikerogammarus villosus and E. ischnus were positively related to chironomids and oligochaetes, respectively. Coexistence of various alien amphipods in the studied area, indicated by prevailing positive relationships in their assemblage, may be enabled by the abundance of shelters and rich food sources allowing habitat partitioning.

Clams from the Corbicula species complex of Asian origin are invasive all over the world, currently extending their distribution to waters of the natural thermal regime in Central European areas. Features linking the clams to their habitats in newly invaded areas have not been fully examined. These include substratum preferences and mobility, which may be key to determining potential niche overlap with native bivalves and gaining a better knowledge of their potential active dispersal and impact. Therefore, our aim was to determine the substratum preferences, horizontal locomotion and burrowing behaviour of three Corbicula morphospecies from Poland, Central Europe: two populations of undetermined Corbicula sp. from an artificially heated habitat and water of the natural thermal regime (cold water), as well as Corbicula leana, and Corbicula fluminea (from artificially heated and cold water, respectively).To determine the preferred substratum range, we used pairwise choice tests with a range of muddy, sandy, and gravelly substrata, as well as zebra mussel shells. Then, we conducted behavioural observations (locomotion and burrowing) by CCTV cameras on substrata found as preferred and non‐preferred by clams.All morphospecies preferred fine‐grained over coarser substrata. C. fluminea from cold water had the widest range of substratum preferences. By contrast, C. leana from artificially heated water and Corbicula sp. from cold water showed the narrowest substratum preferences and spent the longest time deeply burrowed. The longest duration of burrowing activity was noted on non‐preferred coarser substrata, which may indicate difficulties in burrowing. On non‐preferred coarse substrata, C. fluminea (cold water) crawled more than the other morphospecies.Our results show that sediment preferences and behaviour (burrowing and locomotion) differ among various Corbicula morphospecies in Europe, probably also varying their invasive potential.This knowledge is important for determining the overlap of habitat preferences of non‐native Corbicula clams with native bivalves, which is critical for determining potential competition strength, impact, and/or displacement. Our results also indicate that habitats with fine sediments could be more threatened by Corbicula invasions. [ABSTRACT FROM AUTHOR]

Ponto–Caspian goby fish belong to the most successful invaders in freshwater ecosystems of Europe and North America. So far, three alien goby species have been present in the Polish section of the Dnieper–Rhine River corridor: the monkey goby Neogobius fluviatilis, the racer goby Babka gymnotrachelus, and the western tubenose goby Proterorhinus semilunaris. Their assemblages in this region are unique because, in contrast to their native region or the Danube–Rhine corridor, they are unaffected by other gobiid species. We conducted electrofishing and habitat quality surveys to gather information on key environmental factors associated with the distribution of these fish in the lower river Vistula, which constitutes a vast middle part of the corridor used by the Ponto–Caspian species to migrate westward in Europe. We showed that the sandy bottom was beneficial for the monkey goby allowing the species to attain the highest abundance among the gobies in the river. Habitat complexity generated by artificial bank structures, as well as dense macrophyte coverage in the main channel, favoured mostly the expansion of the racer goby. Off‐channel areas with vegetation and a muddy bottom (old river beds and pools) were the most suitable habitats for the western tubenose goby. We did not find any negative spatial relationships among gobies of various species and sizes except the avoidance of the monkey goby by small western tubenose goby. Thus, our study demonstrates substantial habitat partitioning, suggesting a low level of interspecific competition among the three species in a lowland river. [ABSTRACT FROM AUTHOR]