The University of Michigan News Service has an article about an interesting study involving native and non-native cattails. Two biologists performed experiments in Michigan marshes, where the native broad-leaf cattail (Typha latifolia) and introduced narrow-leaf cattail (Typha angustifolia) grow and hybridize (Typha x glauca). Noting that the hybrid was more common than the native broad-leaf, the researchers set up plots with both types of cattails and added leaf litter to some of the plots. Their results indicate that the leaf litter was altering the marsh environment by decreasing soil temperatures and increasing nitrogen levels. Turns out the hybrid has a competitive advantage over the native in that altered environment, so the litter is creating a feedback loop that could feasibly wipe out the native species.
Thanks to Tim over at Walking the Berkshires for sending in a link to this story.