When a plant is introduced (accidentally or intentionally, but usually by humans) into a new region, many factors can influence the ability for that species to become established. One major factor at play is the different set of species it will interact with in this new environment—will they work with it or against it? We naturally tend to focus on the negatives; like whether there are enemies like pathogens, predators or other competitors that will control it.
What has received less attention is how positive interactions are affecting the spread of non-native species. For example, we know that the availability of pollinators is important for many plant species. So when a species moves, it doesn’t just leave its enemies behind, it also leaves its friends, its beneficial partnerships.
And it appears that for symbiotic legumes, these beneficial partners matter a lot. Their associated rhizobia matter so much that we can see their impacts on legume species spread at a global scale, across multiple continents and islands.