As Invasive Species Awareness Week unfolded from February 23-27, 2026, University of Maryland Extension wildlife management specialist Luke Macaulay detailed the widespread damage invasive species inflict on Maryland’s ecosystems and beyond.
Invasive species—non-native plants or animals that spread aggressively—displace native counterparts, often introduced via human actions, leading to economic, environmental, or human harm. Macaulay highlighted their broader ripple effects. “You can have these cascading impacts across the ecosystem,” he said. “If you think about the food web from your elementary days, where you learned how everything was interconnected, one big piece that gets changed has this ripple effect throughout the rest of the ecosystem. So, there are multiple effects from these things spreading on the landscape.”
Maryland harbors more than 300 invasive plant species, per sources aligned with regional invasive plant tracking efforts such as the Mid-Atlantic Invasive Plant Council and related assessments. Notable examples include Japanese knotweed and water chestnut among plants, alongside invasive animals like blue catfish, zebra mussels, and sika deer. Macaulay, whose work centers on invasive plants, stressed their foundational role. “If you think about plants, they are the foundational aspect of the ecosystem,” he emphasized. “If you look at an energy pyramid, all wildlife and the whole ecosystem really starts at the vegetation level because all the photosynthesis comes from the sun. That’s the source of energy for the whole system. You have herbivores that then graze on the plants, and then predators that then eat on herbivores.”
These disruptions alter energy flows, reduce biodiversity, and trigger chain reactions that affect insects, birds, mammals, and overall habitat health in Maryland’s forests, wetlands, and waterways. In Southern Maryland, where agriculture, forestry, and natural areas intersect with the Chesapeake Bay watershed, such changes compound challenges to native vegetation and dependent wildlife.
Macaulay urged residents to inspect properties using mobile identification apps to spot problem species early. Prevention and early detection remain key, as established invasions prove difficult and costly to reverse.
Nationally, invasive species impose an estimated $26 billion in annual damage, according to analyses from the National Invasive Species Information Center and supporting studies that track rising economic burdens from control efforts and losses in agriculture, forestry, and ecosystems. Recent research confirms annual U.S. costs in recent decades averaging around $21 billion or more, with cumulative figures reaching into the trillions over decades when including reliable reported damages.
National Invasive Species Awareness Week, observed annually in late February—including 2026’s February 23-27 period—aims to educate the public and promote actions like removal events, reporting, and responsible landscaping to curb introductions.