Enemy release and biotic resistance are competing, but not mutually exclusive, hypotheses addressing the success or failure of non-native plants entering a new region. Enemy release predicts that exotic plants become invasive by escaping their co-adapted herbivores and by being unrecognized or unpalatable to native herbivores that have not been selected to consume them. In contrast, biotic resi...

Non-native species introductions are widespread and can affect ecosystem functioning by altering the structure of food webs. Invading plants often modify habitat structure, which may affect the suitability of vegetation as refuge and could thus impact predator-prey dynamics. Yet little is known about how the replacement of native by non-native vegetation affects predator-prey dynamics. We hypot...

Extinctions can leave species without mutualist partners and thus potentially reduce their fitness. In cases where non-native species function as mutualists, mutualism disruption associated with species' extinction may be mitigated. To assess the effectiveness of mutualist species with different origins, we conducted a meta-analysis in which we compared the effectiveness of pollination and seed...

BACKGROUND AND AIMS Although urban gardens provide opportunities for pollinators in an otherwise inhospitable environment, most garden plants are not native to the recipient biogeographical region and their value to local pollinators is disputed. This study tested the hypothesis that bumblebees foraging in English urban gardens preferentially visited sympatric Palaearctic-range plants over spec...

Increased livestock densities near artificial watering sites create disturbance gradients called piospheres. We studied responses of alien and native annual plants and native perennial plants within 9 piospheres in the Mojave Desert of North America. Absolute and proportional cover of alien annual plants increased with proximity to watering sites, whereas cover and species richness of native an...

BACKGROUND Entomophilous non-native plants can directly affect the pollination and reproductive success of native plant species and also indirectly, by altering the composition and abundance of floral resources in the invaded community. Separating direct from indirect effects is critical for understanding the mechanisms underlying the impacts of non-native species on recipient communities. OB...