“Something wicked this way comes,” quips the tagline for Jennifer Forman Orth’s blog, invasivespecies.blogspot.com. Orth serves as the state plant pest survey coordinator for the Massachusetts Department of Agricultural Resources and also runs the Massachusetts Introduced Pests Outreach Project.
E: What exactly are invasive species?
JFO: An invasive species is a plant or animal that is not indigenous to a specific area, and when introduced to a new environment causes harm to the ecosystem, to the economy, or to human health.
E: Why are invasive plants a problem for the environment?
JFO: Invasive plants can displace native plant species, which in turn can displace the food sources and habitat of native birds, mammals and insects. They can also negatively impact the ability of the natural environment to provide resources that humans depend on. For example, giant hogweed is a plant that often invades along rivers. It holds the soil poorly…creating much more soil erosion, which in turn can lead to more flood damage. All that soil pouring into rivers can reduce the oxygen in the water, killing fish and aquatic plants.
E: Do invasive plants have any impact on native wildlife?
JFO: Scientists have observed drops in grazing mammal populations in areas where native foraging grasses have disappeared. Frogs in areas infested by Japanese knotweed can’t find food because of the lack of insects and other invertebrates.
E: What about garden plants? Can they be invasive?
JFO: A lot of the better-known invasive plants started out as ornamental plants. In Massachusetts, there are several dozen ornamental species that are now prohibited or are in the process of being phased out by the nursery industry, including burning bush, Japanese honeysuckle and Japanese barberry. Our yards are part of the natural environment. Birds and other small animals pass through and find fruit and seeds to eat. The wind blows by and carries off winged seeds. Other plants spread by underground stems.
E: How can I learn more about invasive species and the threat they pose to the environment?
JFO:Your local cooperative extension office is a good source for information, as are the environmental agencies in your state. The following websites are also good sources for information about invasive species: The Global Invasive Species Database; Alien Plant Invaders of Natural Areas; The Nature Conservancy’s Global Invasive Species Team