Urban environments are often characterized by modified, degraded, and fragmented natural habitats. Fragmented urban habitats create more edge space, altered disturbance regimes, and novel ecosystem conditions which allow invasive species to become established and proliferate quickly. The existing human dispersal and transportation pathways in cities also allow invasive species to thrive. While there are numerous invasive species in Mecklenburg County you can learn more about, below are a few invasive species specifically prevalent within the Little Sugar Creek watershed.
Emerald Ash Borer, Agrilus planipennis
The Emerald Ash Borer (EAB) is a metallic green beetle smaller than a penny and native to parts of Asia and Eastern Russia. It is believed to have arrived in the U.S. as early as the 1990s through international trade using wood packing material. First discovered in Michigan in 2002, the EAB has now spread throughout many central and eastern states, killing millions of ash
trees. While the EAB can spread naturally by flying only a few miles a year, their long-distance dispersal has been facilitated by the transportation of wood products like firewood across the U.S (Veverka, 2022).
The beetles lay eggs on the bark of ash trees and the larvae bore into the bark and feed on the tree's vital tissues, disrupting circulation systems and eventually causing tree death. The EAB was first found in Mecklenburg County around six years ago and has since turned whole areas of urban forests into graveyards (Veverka, 2022).
Since ash trees love floodplains, they are common along greenways like Little Sugar Creek. Insecticides are available to preventatively treat high-value ash trees, but once the tree has been infested, there is no cure for the invasive pest. Trees treated with the EAB insecticide in Charlotte are marked with a blue tag as pictured. Infected trees typically will reveal dead sections around the top, and they will have a telltale small D-shaped exit hole from the beetle in the bark (Veverka, 2022).
Porcelainberry Vine, Ampelopsis brevipedunculata
Native to temperate areas of Asia, the porcelainberry vine was introduced into the U.S around the 1870s as an ornamental landscaping plant. Now widespread across the eastern U.S., it is considered a highly invasive vine as it it fast growing, pest-resistant, and tolerant to harsh conditions. Its seeds are dispersed easily by water and animals (CMSWS, 2005). With woody stems and colorful berries, the porcelainberry closely resemble native grapes. It prefers moist soils and thrives along stream banks, forest edges, or other disturbed areas, where it forms thick mats that shade out native shrubs and trees (NC State Extension, n.d.).
Glossy Privet, Ligustrum lucidum
Native to China, Japan, and Korea, Glossy Privet is a highly-invasive semi-evergreen flowering shrub or small tree that is taking over wooded areas throughout the Eastern United States. A privet (Ligustrum genus) is in the olive family Oleaceae and native to the southern half of China. Glossy Privet was introduced to the U.S. in the 1850s as an ornamental shrub, and it's still commonly used as a hedge (USF, n.d.). Other varieties of privet, including Japanese and Chinese Privet, look very similar and share characteristics that make them highly invasive.
The aggressive nature of privets allows them to form dense thickets that out-compete other vegetation. Privets thrive in floodplain forests, woodlands, and understories, as they are tolerant of a wide range of soil and light conditions. They produce copious amounts of seeds that are spread by birds, which facilitate their rapid dispersal. Small white fragrant flowers form in panicles at the end of their twigs (CMSWS, 2005).
Kudzu, Pueraria montana
The deciduous woody vine Kudzu is perhaps one of the most infamous invasive plants across the southeastern U.S., known for its ability to spread like wildfire and the nearly impossible nature of removing it. Native to Japan and China, Kudzu was first introduced to the U.S. in 1876 at the Philadelphia Centennial Exposition. It quickly became popular as an ornamental shade plant and was later used for erosion control measures in southern agriculture (Calton, 2006).
With the ability to grow up to a foot per day, kudzu has become known as "the vine that ate the South." The vine spreads through runners, rhizomes, and vines that are able to root at nodes to form new plants (The Nature Conservancy, 2019). Kudzu can climb trees and buildings, and it spreads rapidly across field edges, riparian areas, roadsides, disturbed habitats, and forest edges. As it grows, kudzu forms a thick mat that blocks out the light and suffocates any vegetation underneath.
References:
Calton, B. (2006). Kudzu. NCpedia. https://www.ncpedia.org/kudzu
Charlotte-Mecklenburg Stormwater Services. (2005). Invasive Exotic Plants of Charlotte and Mecklenburg County. 6–45. Charlotte, NC; Charlotte-Mecklenburg Storm Water Services. Retrieved from https://www.charlottenc.gov/files/sharedassets/city/v/2/services/stormwater/documents/water-quality/print-media/exoticplantsbookletscan.pdf.
NC State Extension. (n.d.). Ampelopsis brevipedunculata. North Carolina Extension Gardener Plant Toolbox. https://plants.ces.ncsu.edu/plants/ampelopsis-brevipedunculata/
NC State Extension. (n.d.). Ligustrum lucidum. North Carolina Extension Gardener Plant Toolbox.
University of South Florida. (n.d.). Ligustrum Lucida. FLIP: Florida Invasive Plants. https://plantatlas.usf.edu/flip/plant.aspx?id=34
The Nature Conservancy. (2019, August 9). Kudzu: The invasive vine that ate the South. https://www.nature.org/en-us/about-us/where-we-work/united-states/indiana/stories-in-indiana/kudzu-invasive-species/
Veverka, A. (2022, June 13). Bark-Devouring Beetles are Killing Charlotte’s Greenway Ash Trees. UNC Charlotte Urban Institute. https://ui.charlotte.edu