Abstract In 2017 and 2019 two horizon scan workshops were undertaken for the island of Cyprus, which focused on making predictions about the invasive alien species (IAS) most likely to arrive and impact biodiversity, human health and the economy. Herein, we assess the species lists derived from these two horizon scans and consider the accuracy of the predictions so far. In less than ten years, 26 new IAS were found in Cyprus, 10 out of which were predicted to arrive by the horizon scans. Eight introduced IAS were ranked as high risk during the horizon scanning process. Horizon scanning helped raise awareness amongst the authorities, scientists and the public, leading in some cases to a rapid response by the competent authorities to control the arrival. We conclude that horizon scanning is a useful process that can inform contingency planning and action. Furthermore, it facilitates communication between IAS experts, policy makers and society, encouraging active engagement and raising awareness regarding the importance of early warning, rapid response and management of IAS. We propose that the horizon scanning process for the island of Cyprus is repeated regularly, recognizing the ongoing increase in the number of new IAS arriving year on year.

Abstract Preventing the spread of small, cryptic invasive reptiles poses an ongoing challenge for conservation and biosecurity worldwide. Physical exclusion barriers offer a potentially low-cost, non-toxic tool for limiting dispersal, but their effectiveness depends on, among other factors, a detailed understanding of how surface properties influence animal movement. We tested four commonly available fencing materials—polypropylene fabric, woven polypropylene, polythene sheet, and acrylic sheet—as potential barriers to climbing by a small Australian skink, Lampropholis delicata (Scincidae). Experiments with 18 adult skinks were conducted in enclosures under both wet and dry conditions. We quantified surface roughness using four metrics: arithmetic average roughness (Ra), total height of profile (Rt), mean spacing of profile irregularities (Rsm) and Skewness (Rsk). Climbing frequency was highest on the roughest material, polypropylene fabric (Ra = 25, Rt = 167, Rsm = 457.5 µm), with up to 60% of individuals climbing. In contrast, the smoother surfaces, polythene and acrylic, limited climbing to just 5% of trials, with climbs occurring only under wet conditions. This suggests that surface water may enhance adhesion and reduce the effectiveness of smooth barriers. Our findings indicate that simple vertical drift fences are unlikely to effectively manage the spread of L. delicata , particularly in wet environments and underscore the importance of incorporating surface roughness thresholds and moisture conditions into barrier design. Polythene sheet, shows promise for indoor containment but would require modifications such as anti-climb lips for outdoor use. Tailored exclusion strategies that integrate material science with animal behaviour and ecological context could offer scalable, environmentally friendly tools for containing and managing invasive species.

Abstract We report the first confirmed occurrence of Arion subfuscus (Arionidae) in Japan—also the first Arion ever documented there. Specimens collected in 2024 in Hokkaido (northern Japan) were identified by morphology and mitochondrial 16S sequencing. Phylogenetic analyses placed the Japanese individuals within the S1 clade of A. subfuscus , sharing a haplotype previously reported from multiple sites in North America (and also recorded in Western Europe). These genetic data suggest a multi-step invasion pathway, originating in Europe, passing via North America, and ultimately reaching Japan. Observed mating pairs in the field and egg-laying in captivity confirm local establishment. According to long-term data from the Japan Meteorological Agency (JMA), annual precipitation in northern Japan has increased over the past decades. Concurrently, expanding global trade and shipping routes have increased propagule pressure between these regions. The combined influence of climate change and globalization likely facilitated this transcontinental invasion. Given the ecological risks posed by invasive Arion (crop damage, pathogen transmission, and native gastropod displacement), our study underscores the need for vigilant biosecurity monitoring and inspection at major trade gateways to prevent further spread.

Abstract The role of native species richness in mediating ecosystem resistance to exotic plant invasion is thought to arise from niche filling and resource limitation that influence the competitive ability of an invader. However, there is a lack of empirical evidence examining the role of species richness and light availability during an invasion event. Here, a mesocosm experiment with constructed grassy woodland understory communities were used to examine the effects of native richness and light availability on the invasion success, growth and leaf traits of two invasive grasses, Paspalum dilatatum Poir. and Eragrostis curvula (Shrad.) Nees. Native species richness significantly reduced the emergence, survival and above-ground biomass of both invasive grasses. However, interspecific variation in the relative and specific leaf area and intraspecific variation induced by different light and richness treatments was observed in both species. Strong negative relationships were identified between the above-ground biomass of both invasive and native grasses, which may indicate competitive interactions. Conversely, a positive relationship was observed between E. curvula and the biomass of native shrubs indicative of a facilitation effect. Distance-based linear modelling revealed community resistance to both invasive species manifested most strongly with the inclusion of multiple native species from differing functional groups, suggesting that complementarity mediated by functional trait diversity is a principal component of biotic resistance to invasion in this system. These results provide evidence that species richness confers invasion resistance beyond interspecific, competitive mechanisms and may limit establishment success and trait expression.