Seeds of change
The cover shows a silvereye (Zosterops lateralis), a bird native to New Zealand, perched on Chilean rhubarb (Gunnera tinctoria), a species that has been introduced to the country. Trade and transportation have helped to accelerate the introduction of species, both plant and animal, to new regions. In this week’s issue, Evan Fricke and Jens-Christian Svenning analyse the effects such introductions have on the mutualistic networks of fleshy-fruited plants and the animals that eat those fruits and so disperse the seeds. The researchers looked at 410 local networks, encompassing 24,455 unique pair interactions between 1,631 animal and 3,208 plant species. They found that introduced species blur the biogeographical patterns of the global network, and disproportionately facilitate the success of other introduced species. As a result, the researchers say, the resilience of local ecosystems is increasingly at risk from biotic homogenization.