Native plants regenerate after removal of invasive shrubs, states study

A new study has shown that native plants regenerate on their own when invasive shrubs are removed.

The study was published in the journal 'Invasive Plant Science and Management'.

Invasive shrubs have become increasingly prevalent in the deciduous forests of eastern North America - often creating a dense understory that outcompetes native plants.

Researchers manually removed 18 species of invasive shrubs from five plots in a mature, deciduous forest in the Eastern United States. They cut the shrubs off at the base with hand clippers and treated foliage emerging from stumps and roots with herbicides. Any new seedlings were removed each spring.

Seven years after the initial removal, native plants had regenerated and filled the gap on their own - and they did so to a much greater extent than expected. Researchers found a significant increase in plant diversity and abundance among both native understory species and small trees.

"Natural regeneration in the areas where invasive shrubs had been removed actually exceeded the growth of native cover in unmanaged forest control plots - even those where no invasive shrubs were found," said Erynn Maynard-Bean of Pennsylvania State University.

"The results suggest that invasive shrub removal can make sense, even when active steps to restore the native plant community aren't possible.