a r t i c l e i n f o Introduced habitat-providing organisms such as epibenthic bivalves may facilitate the invasion and expansion of further non-native species which may modify the effects of the primary invader on the native system. In the sedimentary intertidal Wadden Sea (southeastern North Sea) introduced Pacific oysters (Crassostrea gigas) have overgrown native blue mussel beds (Mytilus e...

Empirical studies suggest that most exotic species have fewer parasite species in their introduced range relative to their native range. However, it is less clear how, ecologically, the loss of parasite species translates into a measurable advantage for invaders relative to native species in the new community. We compared parasitism at three levels (species richness, abundance and impact) for a...

Riparian forests exhibit levels of ecological disturbance that leave them especially prone to biological invasions. Japanese knotweed (Fallopia japonica) is particularly suited to these habitats and is an aggressive invader along watercourses throughout its now-global range as an exotic invader. Using one of the few Silver Maple Floodplain Forest communities that has not been invaded by F. japo...

We study the consequences of omnivory on the dynamic behaviour of a three species food web under chemostat conditions. The food web consists of a prey consuming a nutrient, a predator consuming a prey and an omnivore which preys on the predator and the prey. For each trophic level an ordinary differential equation describes the biomass density in the reactor. The hyperbolic functional response ...

The importance of species richness for repelling exotic plant invasions varies from ecosystem to ecosystem. Thus, in order to prioritize conservation objectives, it is critical to identify those ecosystems where decreasing richness will most greatly magnify invasion risks. Our goal was to determine if invasion risks greatly increase in response to common reductions in grassland species richness...

Th ere are countless examples of management projects that have attempted to decrease or eradicate invasive species at a site, only to have them rapidly recolonize within a few years. While this is often attributed to reinvasion through propagules remaining at the site, or high propagule pressure from the surrounding landscape (Leung et al., 2004; Lockwood et al., 2005), this also may be due to ...

Natural ecosystems show variable resistance to invasion by alien species, and this resistance can relate to the species diversity in the system. In soil, microorganisms are key components that determine life support functions, but the functional redundancy in the microbiota of most soils has long been thought to overwhelm microbial diversity-function relationships. We here show an inverse relat...

Mono-dominance by invasive species provides opportunities to explore determinants of plant distributions and abundance; however, linking mechanistic results from small scale experiments to patterns in nature is difficult. We used experimentally derived competitive effects of an invader in North America, Acroptilon repens, on species with which it co-occurs in its native range of Uzbekistan and ...

Whether dominance drives species loss can depend on the power of conspecific self-limitation as dominant populations expand; these limitations can stabilize competitive imbalances that might otherwise cause displacement. We quantify the relative strength of conspecific and heterospecific soil feedbacks in an exotic-dominated savannah, using greenhouse trials and field surveys to test whether do...