First Author

Predicting whether a non-native invasive plant species is likely to overtake a given ecosystem can be tricky. But being able to make such predictions would be valuable, because invasive species can have serious ecological and economic consequences. Researchers generally believe that invasive plants thrive best when resource levels — nutrients, water and sunlight — are plentiful. But as an undergraduate visiting Hawaii, Jennifer Funk, now a postdoc at Stanford University in California, found this puzzling. Despite having low-nutrient volcanic soils, the islands are overrun with invasives. She and colleague Peter Vitousek compared the resource-use efficiency of 19 invasives with that of 19 evolutionarily related natives. They report, on page 1079, that invasives are as efficient as or more so than native plants at using limited resources. Funk tells Nature about her trek across paradise to study these plants.

Why have there been so few studies of invasives in low-resource environments?

Most invasive species are found in disturbed habitats, which are often characterized by high resource availability. For example, if you harvest some of the trees in a forest, you increase the amount of light available to the remaining trees and plants. Research in disturbed systems suggests that invasive plants are able to exploit high-resource conditions. But it's widely thought that natives in low-resource environments should be able to outcompete invasives, because the natives have traits that allow them to persist there.

How did you decide which species to look at?

I used evolutionarily related pairs of native and invasive plants, comparing an invasive and native plant from either the same genus or the same plant family. Closely related species have more traits in common, which makes it easier to identify the trait or traits making an invasive plant more aggressive.

How did you determine the performance of natives versus invasives?

We looked at resource-use efficiency, which is the amount of carbon that a plant assimilates through photosynthesis per amount of resource used to acquire that carbon.

What further studies might help determine better ways to manage invasives?

It would be interesting to look at how resource-use efficiency operates at different phases of invasion. For example, if a grass invading an arid environment has very high water-use efficiency, you might want to target the removal of that invasive plant before it becomes problematic, because it's likely to outcompete the native vegetation for the most limited resources.