Development and application of a second-generation multilingual tool for invasion risk screening of non-native terrestrial plants.

Under the increasing threat to native ecosystems posed by non-native species invasions, there is an urgent need for decision support tools that can more effectively identify non-native species likely to become invasive. As part of the screening (first step) component in non-native species risk analysis, decision support tools have been developed for aquatic and terrestrial organisms. Amongst these tools is the Weed Risk Assessment (WRA) for screening non-native plants. The WRA has provided the foundations for developing the first-generation WRA-type Invasiveness Screening Kit (ISK) tools applicable to a range of aquatic species, and more recently for the second-generation ISK tools applicable to all aquatic organisms (including plants) and terrestrial animals. Given the most extensive usage of the latter toolkits, this study describes the development and application of the Terrestrial Plant Species Invasiveness Screening Kit (TPS-ISK). As a second-generation ISK tool, the TPS-ISK is a multilingual turnkey application that provides several advantages relative to the WRA: (i) compliance with the minimum standards against which a protocol should be evaluated for invasion process and management approaches; (ii) enhanced questionnaire comprehensiveness including a climate change component; (iii) provision of a level of confidence; (iv) error-free computation of risk scores; (v) multilingual support; (vi) possibility for across-study comparisons of screening outcomes; (vii) a powerful graphical user interface; (viii) seamless software deployment and accessibility with improved data exchange. The TPS-ISK successfully risk-ranked five representative sample species for the main taxonomic groups supported by the tool and ten angiosperms previously screened with the WRA for Turkey. The almost 20-year continuous development and evolution of the ISK tools, as opposed to the WRA, closely meet the increasing demand by scientists and decision-makers for a reliable, comprehensive, updatable and easily deployable decision support tool. For terrestrial plant screening, these requirements are therefore met by the newly developed TPS-ISK.

When a river is affected by a reservoir: Trophic interactions and flexibility in feeding strategies of alpine bullhead (Cottus poecilopus) and European bullhead (Cottus gobio).

The alpine bullhead and European bullhead are benthic fish species protected by law in several European countries. One of the problems of European rivers is the ever-increasing number of reservoirs, which has adverse impacts on aquatic ecosystems. Feeding ecology of both species evaluated separately has been a subject of several studies, however, none of the studies paid attention to feeding interactions between them. Thus, the aims of the study were to evaluate trophic interactions of the two bullhead species and to assess their ability to cope with environmental disturbances caused by a reservoir. The study area consisted of three sites on the river Cierny Váh (Slovakia) that differed from each other by the intensity of pressures posed by the reservoir. The two species were found to coexist at two sites below the reservoir, because the reservoir affected their distribution along the river. For alpine bullhead, chironomid, hydropsychid and baetid larvae were the most important prey items, whereas the diet spectrum of European bullhead contained hydropsychid, chironomid larvae and detritus. Differences in diet composition were found among sampling sites. Temporal variations in the diet composition demonstrated that alpine bullhead is a more flexible feeder than European bullhead. Being predominantly food generalists, both species were able to shift their feeding strategies towards specialization when exposed to environmental disturbances at the most affected site. The reservoir increased the diet overlap between the two species, and thus changed their trophic interactions. Both alpine bullhead and European bullhead managed to cope with environmental disturbances caused by the reservoir, however, in lower population densities. Moreover, the reduced diversity of resources increased the potential for trophic competition between them.

Ontogenetic variations in the diet of two invasive gobies, Neogobius melanostomus (Pallas, 1814) and Ponticola kessleri (Günther, 1861), from the middle Danube (Slovakia) with notice on their potential impact on benthic invertebrate communities.

In this study, ontogenetic variations in diet of invasive bighead goby Ponticola kessleri and round goby Neogobius melanostomus from the middle Danube were analysed. Index of stomach fullness, Fulton's condition factor, index of food importance, frequency of occurrence, biomass, electivity, and proportions of invasive organisms in their diet were examined. Changes in the diet during ontogeny of both species emphasise the differences in their trophic niches. Our results combined with literary data suggest that bighead goby may threaten small native benthic fish species as a predator (especially in the invasion front), whereas round goby can potentially impact native fish species of all ontogenetic phases by competing for food. Round goby appear to have strong impact on bivalves, especially in the invasion front. High consumption of invasive organisms by bighead goby may help the native macroinvertebrate community. Thus, in contrast to round goby, bighead goby does not seem to be a hot candidate for being a nuisance invader.