Invasive species are typically a bane to land managers, who often devote considerable time and expense to controlling or removing them. But a new study of coastal dunes at New Jersey’s Island Beach State Park finds that one invasive plant, Asiatic sand sedge (Carex kobomugi), which grows on beach dunes, has at least one redeeming quality.

According to work led by Bianca Charbonneau, a Ph.D. student in the Department of Biology in the School of Arts & Sciences, C. kobomugi is more effective than its native counterpart, American beach grass (Ammophila breviligulata), at preventing dune erosion during big storms, like Superstorm Sandy. The findings, published in the Journal of Applied Ecology, may help guide management activities, especially as climate change fuels greater numbers of strong hurricanes along the coast.

“In order to make an informed management decision, you really need to know all the cards at play and this is an important one,” says Charbonneau. “It seems that not all species are created equal with regard to their ability to stabilize dunes and combat erosion in the face of a storm.”

C. kobomugi was first found at Island Beach State Park in 1929, and grows in stands that are separate from those of A. breviligulata. Charbonneau and her colleagues were able to compare the effect of the two species on dune erosion by using GPS data on species distributions, along with aerial images and elevation data of the dunes before and after Superstorm Sandy, which ravaged the East Coast in October of 2012. Their analysis revealed a significant species effect in how much erosion, both in terms of volume and movement of the crest from east to west, the dunes experienced from the storm. 

“Across the park, approximately three meters [around 10 feet] more dune was lost in native grass stands compared to areas stabilized by the invasive,” Charbonneau says.

Because C. kobomugi is known to be aggressive and reduce local biodiversity, Charbonneau doesn’t foresee managers letting it run rampant. But they have already rethought their previous zero-tolerance policies.

“Prior to this research, the park was trying everything to get rid of this invasive, but no more,” Charbonneau says. “I think that, while we still want to control it, any eradication effort needs to coincide with a planting to ensure the dune remains stabilized.”