Notes from the Field - December 2017

By: Brooke Milligan, Director of Conservation

Beach vitex (Vitex rotundifolia), an invasive dune species, grows rapidly, up to 33 cm vertically and 330 cm laterally with >20,000 seeds/m2 annually. Beach vitex has a very shallow root system and does not stabilize the dune, although it was once believed to be a dune stabilizer. The integrity of the BHI dune system, which is strongly correlated with the prevalence and health of native vegetation, is of utmost importance as the island combats chronic erosion, storm events, and rising sea levels. Unmanaged, beach vitex quickly dominates the dune habitat producing a monoculture that can impede sea turtle nesting and shorebird foraging and exacerbates storm erosion.
In 2005, the Village of BHI (VBHI) began contracting the Bald Head Island Conservancy (BHI Conservancy) to identify and apply pesticides to this invasive dune species. BHI Conservancy staff and interns have been busy with the fall 2017 treatment of beach vitex. Treatment involves painting an herbicide, Imazapyr, on the plant after cutting into the stem. A runner, or exposed root, has to be treated each time it goes into the ground, which can be a very daunting task.
In 2017, BHI Conservancy staff and interns have committed over 100 hours to the treatment of known BHI beach vitex locations. The BHI Conservancy begins with treatment on larger plants moving to progressively smaller plants. The larger plants can take up to three days to treat depending on the size and spread of the runners. While the treatment of beach vitex can seem overwhelming, the benefits of continual treatment will be seen for years to come. If left unchecked, the plant could end up costing thousands in mitigation efforts to restore the BHI dune system. In the future, the BHI Conservancy hopes to improve its surveying techniques through the use of drones. This will not only cut survey time but will work to further protect the BHI dune system by reducing the impact of surveying on foot. 
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