Invasive alien species (IASs) on islands have broad impacts across biodiversity, agriculture, economy, health and culture, which tend to be stronger than on continents. Across small-island developing states (SIDSs), although only a small number of IASs are widely distributed, many more, including those with greatest impact, are found on only a small number of islands. Patterns of island invasion are not consistent across SIDS geographic regions, with differences attributable to correlated patterns in island biogeography and human development. We identify 15 of the most globally prevalent IASs on islands. IAS impacts on islands are exacerbated through interactions with a number of other global change threats, including over-exploitation, agricultural intensification, urban development and climate change. Biosecurity is critical in preventing IAS invasion of islands. Eradication of IASs on islands is possible at early stages of invasion, but otherwise is largely restricted to invasive mammals, or otherwise control is the only option. Future directions in IAS management and research on islands must consider IASs within a broader portfolio of threats to species, ecosystems and people's livelihoods on islands. We advocate for stronger collaborations among island countries and territories faced with the same IASs in similar socio-ecological environments.

Most turfgrass species have been listed as either invasive or potentially invasive species in the U.S., but few data exist to verify their invasiveness. Our objective was to determine cool-season turfgrass survival on two abandoned golf courses to assess their invasive potential in unmanaged sites. Maintenance operations ceased at Matheson Greens Golf Course in 2000 and at Four Winds Golf Course in 2003. The frequency and abundance of creeping bentgrass, Kentucky bluegrass, and fine fescues in quadrats placed along transects were recorded and compared to other cover such as herbaceous dicots and bare soil in 2005 and 2007. Turfgrasses at both courses were unable to maintain monocultures. All turfgrasses were nearly absent from Matheson Greens Golf Course 5 yr after maintenance operations ceased. At the Four Winds Golf Course site, creeping bentgrass comprised less than 25% cover on former putting greens by 2007, and was rarely found outside of the former putting green areas. Kentucky bluegrass cover ranged from 5 to 75% on the former fairways. Herbaceous dicots usually dominated the former turf areas at both sites, and included noxious weeds such as Canada thistle and invasive weeds such as spotted knapweed.

Soil and adjacent leaf-litter environments support a diverse decomposer fauna. This has led to what is known as ‘the enigma of the soil fauna’, or the question of how it is possible for such large numbers of species to coexist without obvious biotic mechanisms, such as competitive exclusion, limiting coexistence (Anderson 1975). Dietary specialization or effective partitioning of food resources could be a mechanism to avoid niche overlap among sympatric soil/litter species (Chahartaghi et al. 2005, Jennings & Barkham 1975). However, unravelling the complexities of trophic relationships can be difficult, especially in soil/leaf-litter habitats where both consumers and prey are small, diverse and often unidentifiable (Scheu & Falca 2000). As such, the trophic relationships among species in these habitats typically remain unresolved.

The introduction of invasive species may be the most profound modern threat to biological communities in high-latitude regions. In the Southern Ocean, the natural transport mechanism for shallow-water marine organisms provided by kelp rafts is being increasingly augmented by plastic debris and shipping activity. Plastic debris provide additional opportunities for dispersal of invasive organisms, but dispersal routes are passive, dependent on ocean currents, and already established. In contrast, ships create novel pathways, moving across currents and often visiting many locations over short periods of time. Transportation of hull-fouling communities by vessel traffic thus poses the most likely mechanism by which exotic species may be introduced to the Southern Ocean.