Introduced species shed friends as well as enemies

TL;DR

Introduced species lose both harmful and helpful organisms when moving to new regions, affecting their success.

Contribution

The study shows introduced plants lose more pollinators in new ranges, highlighting mutualist loss as a novel factor in invasions.

Findings

Plants had 2.6 times more pollinator visits in their native range.

Pollinator richness was 1.8 times higher in native than introduced ranges.

Abstract

Many studies seeking to understand the success of biological invasions focus on species’ escape from negative interactions, such as damage from herbivores, pathogens, or predators in their introduced range (enemy release). However, much less work has been done to assess the possibility that introduced species might shed mutualists such as pollinators, seed dispersers, and mycorrhizae when they are transported to a new range. We ran a cross-continental field study and found that plants were being visited by 2.6 times more potential pollinators with 1.8 times greater richness in their native range than in their introduced range. Understanding both the positive and negative consequences of introduction to a new range can help us predict, monitor, and manage future invasion events.

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