Invasive, non-native plant species are “rapidly invading” northern forests in Pennsylvania because of fracking in the Marcellus shale basin, a group of Penn State researchers say.
The spread of invasive plants could have longterm detrimental consequences for forest ecosystems, animals and birds, timbering and ecotourism, the researchers say.
Invasive plant seeds in gravel and mud are being spread by the tires and undercarriages of fracking equipment and trucks, the researchers found.
The seeds find an ideal home in new openings in the forest created by wells, service roads and pipelines.
A team of researchers in Penn State’s College of Agricultural Sciences did invasive plant surveys on Marcellus shale gas well pads and adjacent access roads throughout the Allegheny National Forest.
Surrounding plant communities also were surveyed on a randomly selected set of 32 well pads. Invasive plants were found in greater density on disturbed well pad edges than in surrounding plant communities.
“Given the fact that, on average, 1,235 one-day truck trips delivering fracturing fluid and proppant are required to complete an unconventional well, the potential to transport plant propagules is significant,” said Kathryn Barlow, a doctoral degree candidate in ecology.
Propagules are parts of a plant that can generate new plants, such as seeds.
The researchers said non-native plants such as Japanese stiltgrass, reed canary grass, spotted knapweed, creeping thistle and crown vetch were the most common invasives found.
“Studies have shown that when invasive species move into an area, it changes the plant community, and native plants tend to decline,” said David Mortensen, professor of weed and applied plant ecology.
“Soon we will see a ripple effect in the forest ecosystem that will affect organisms that depend on the native plants.”
Timbering revenue will eventually be affected because deer tend to avoid non-native plants. They will pick through invasive plants and nip any young tree seedlings, hindering growth of the forest, Mortensen said.
“As a result, the recruitment of economically important tree species will be curtailed. This process can be really damaging to the health of the forest in the long run, and even in the short term.”