The Role of Tourism and Recreation in the Spread of Non-Native Species: A Systematic Review and Meta-Analysis

Managing the pathways by which non-native species are introduced and spread is considered the most effective way of preventing species invasions. Tourism and outdoor recreation involve the frequent congregation of people, vehicles and vessels from geographically diverse areas. They are therefore perceived to be major pathways for the movement of non-native species, and ones that will become increasingly important with the continued growth of these sectors. However, a global assessment of the relationship between tourism activities and the introduction of non-native species–particularly in freshwater and marine environments–is lacking. We conducted a systematic review and meta-analysis to determine the impact of tourism and outdoor recreation on non-native species in terrestrial, marine and freshwater environments. Our results provide quantitative evidence that the abundance and richness of non-native species are significantly higher in sites where tourist activities take place than in control sites. The pattern was consistent across terrestrial, freshwater and marine environments; across a variety of vectors (e.g. horses, hikers, yachts); and across a range of taxonomic groups. These results highlight the need for widespread biosecurity interventions to prevent the inadvertent introduction of invasive non-native species (INNS) as the tourism and outdoor recreation sectors grow

Grazing rates of Elysia tomentosa on native and introduced Caulerpa taxifolia

The marine alga Caulerpa taxifolia Vahl (C. Agardh), recognized globally as one of the most prolific non-native species introductions, has been introduced to several temperate locations from where it has since rapidly expanded. C. taxifolia is protected by a toxin (terpenoid) in its tissues that limits grazing by native herbivores. Sacoglossan molluscs of the genus Elysia are among the few organisms that graze C. taxifolia; however, little is known about their feeding ecology. In the current study, we quantified the grazing rates of Elysia tomentosa on native C. taxifolia (Moreton Bay, Queensland) and introduced C. taxifolia (Botany Bay and Lake Conjola, New South Wales). Grazing rates were similar at Moreton Bay sites and Botany Bay; however, they were significantly lower in Lake Conjola. At the maximum observed grazing rate, slugs ate their body weight in C. taxifolia (dry weight) every 18-24 h. Differences in grazing rates between locations may be explained by differences in C. taxifolia morphology rather than native or introduced origin

Habitat preference of three common fishes for seagrass, Caulerpa taxifolia, and unvegetated substrate in Moreton Bay, Australia

A decrease in seagrass cover and a commensurate increase in Caulerpa taxifolia distribution in Moreton Bay have prompted concern for the impact that habitat change may have on faunal communities. Therefore, it is important to understand the patterns of habitat use. We examined habitat selection of three common seagrass species: double-ended pipefish (Syngnathoides biaculeatus), eastern trumpeter (Pelates quadrilineatus), and fan-bellied leatherjacket (Monacanthus chinensis) using a mesocosm experiment. Fish were given three possible habitat pairings (1) seagrass and C. taxifolia, (2) seagrass and unvegetated, and (3) C. taxifolia and unvegetated. Observation trials were conducted during the day and night over two days. In all trials, fish preferred vegetated habitat (seagrass or C. taxifolia) over unvegetated habitat (sand). In seagrass and C. taxifolia trials, all species preferred seagrass significantly over C. taxifolia. Habitat use patterns did not differ between day and night trials. Caulerpa taxifolia provides a valuable structured habitat in the absence of seagrass; however, it is unclear if C. taxifolia meadows provide other resource benefits to fishes beyond that of shelter