National Invasive Species Information Center (2023)

FAQs

What is the biggest cause of invasive species today? ›

Invasive species are primarily spread by human activities, often unintentionally. People, and the goods we use, travel around the world very quickly, and they often carry uninvited species with them. Ships can carry aquatic organisms in their ballast water, while smaller boats may carry them on their propellers.

Notable examples of invasive plant species include the kudzu vine, Andean pampas grass, English ivy, Japanese knotweed, and yellow starthistle. Examples of invasive animals include the New Zealand mud snail, feral pig, European rabbit, grey squirrel, domestic cat, carp, and ferret.

Invasive species are often successful in their new ecosystems because they can reproduce and grow rapidly, or because their new environment lacks any natural predators or pests. As a result, invasive species can threaten native species and disrupt important ecosystem processes.

An invasive species is an introduced, nonnative organism (disease, parasite, plant, or animal) that begins to spread or expand its range from the site of its original introduction and that has the potential to cause harm to the environment, the economy, or to human health.

Herbicides are among the most effective and resource-efficient tools to treat invasive species. Most of the commonly known invasive plants can be treated using only two herbicides—glyphosate (the active ingredient in Roundup™ and Rodeo™) and triclopyr (the active ingredient in Brush-BGone™ and Garlon™).

Invasive species are capable of causing extinctions of native plants and animals, reducing biodiversity, competing with native organisms for limited resources, and altering habitats. This can result in huge economic impacts and fundamental disruptions of coastal and Great Lakes ecosystems.

Invasive species are almost always spread by human activity. The increase of activities such as tourism and trade have meant people and goods can move all over the planet, and they often take invasive species with them, accidentally or intentionally.

So why should we care? Invasive species cause harm to native species in the form of food, water, and shelter competition. Just like cities get overpopulated, so do ecosystems. This competition can cause the native species to face extinction!

Humans have effectively become an invasive species, taking over the homes and resources of animals across the globe. People continue to expand into new lands and territories to compensate for an ever-growing population, converting natural land into cities with homes, offices, shopping centers, and more.

Invasive species can have a number of negative impacts on the areas that they invade. Perhaps the most significant of these is the widespread loss of habitat. The hemlock woolly adelgid is an invasive insect from Asia that rapidly kills infested hemlock trees.

How do invasive species affect populations? ›

Species invasion is of increasing concern as non-native species often have negative impacts on ecosystems that they were introduced to. Invaders negatively affect the abundance of native species due to direct interactions like predation and competition.

Context is everything: some species are clearly harmful to biodiversity and ecosystem function; others may have benefits. Some, like the green crab, might be both good and bad, depending on context.

For an introduced plant to become an invader, it has to 1) arrive, 2) survive, and 3) thrive. The plant must find a vector which will bring it to a new environment.

Some introduced species have been vital in the fight against biodiversity loss, control of invasive species and adaptation to climate change.

According to the World Conservation Union, invasive alien species are the second most significant threat to biodiversity, after habitat loss. In their new ecosystems, invasive alien species become predators, competitors, parasites, hybridizers, and diseases of our native and domesticated plants and animals.

The economic and social impacts of invasive species include both direct effects of a species on property values, agricultural productivity, public utility operations, native fisheries, tourism, and outdoor recreation, as well as costs associated with invasive species control efforts.

The estimated damage from invasive species worldwide totals more than $1.4 trillion, or five percent of the global economy. The annual U.S. cost from invasives is estimated to be $120 billion, with more than 100 million acres affected (i.e., about the size of California).

What are the top 10 most invasive species? ›

Welcome to the "Kudzu Project." Kudzu are a breed of spiraling, scaling, spreading vines native to Japan. The plants are, according to legend, the most invasive plant species in the world, possessed with the ability to climb over trees so quickly they suffocate and kill the branches and trunks they shade from the sun.

In their new ecosystems, invasive alien species become predators, competitors, parasites, hybridizers, and diseases of our native and domesticated plants and animals. It takes the right conditions for an alien species to become established and grow.

Humans have effectively become an invasive species, taking over the homes and resources of animals across the globe. People continue to expand into new lands and territories to compensate for an ever-growing population, converting natural land into cities with homes, offices, shopping centers, and more.

Domestic dogs are rated to be amongst the top five invasive animal species on Earth (Doherty et al., 2017).

The national focus on invasive species arose in the 19th century, primarily owing to losses in agriculture (due to weeds or plant diseases), the leading industry of the time. A few recently arrived invasive species, and estimates of adverse economic impacts exceeding $100 billion annually have sharpened that focus.

Today, more than 100 million feral and outdoor cats function as an invasive species with enormous impacts. Every year in the United States, cats kill well over 1 billion birds.

In short, sunflowers may not be everyone's favorite plant, but they're far from a useless weed or invasive threat.

Almost all grazing animals can eat kudzu, including sheep. Sheep and goats are the primary grazers on kudzu. Some studies have shown that sheep prefer kudzu over grasses or commercial hay when given the choice. While most parts of the plant are edible, different animals have different preferences.

How do humans impact invasive species? ›

Invasive species are almost always spread by human activity. The increase of activities such as tourism and trade have meant people and goods can move all over the planet, and they often take invasive species with them, accidentally or intentionally.

Social and Aesthetics Impacts

reduced property values. damage to private property and infrastructure. loss of traditional food and medicinal plants. reduced land and water recreational opportunities.

Invasive species are capable of causing extinctions of native plants and animals, reducing biodiversity, competing with native organisms for limited resources, and altering habitats. This can result in huge economic impacts and fundamental disruptions of coastal and Great Lakes ecosystems.