In the U.S., over 900 plant species are listed as endangered or threatened. When compared to more than 250,000 vascular plants worldwide, this number seems very small. Vascular plants move water, nutrients, and minerals from the roots to the leaves and back to the root by using an advanced system. This system works similarly to a pipe going from the top to the bottom of the plants. Nevertheless, the loss of any of these vascular plants could cause some organisms that depend on the existence of these plants to lose their home or source of food.

Biodiversity refers to the variety of living organisms within an ecosystem in the world. It includes plants, animals, fungi and microorganisms. It is heavily concentrated in the tropical ecosystems worldwide. In a study, researchers found that Latin America may be home to at least a third of global biodiversity with 118,308 vascular plants (Raven et al., 2020)

Table 1. Estimated total number of described species across tropical regions (Raven et al., 2020).


Number of Vascular Plants

Number of Butterflies

Number of Breeding Birds

Latin America

(Mexico Southward)





(Africa south of the Sahara Desert plus Madagascar)




Southeast Asia




In every large or small ecosystem, all organisms form a harmonious link with each other in a complex, stable and sustainable environment. In fact, a loss in any part of this link could result in a great loss to the whole ecosystem.

A good example is Mead’s milkweed. This is a native plant to the Midwest region. It is also a special plant for Monarch butterflies during its migration, because their caterpillars depend on it for food. Unfortunately, this plant has become scarce, as its tallgrass prairie habitats have been destroyed. After some time, this habitat loss affects the populations of Monarch butterflies and perhaps, other pollinators as well. In a recent study, researchers showed that the decline in the numbers of overwintering monarchs is not due to the increase in deaths during migration, but it’s more likely due to the loss of milkweed during summer breeding season (Taylor et al., 2020).

To learn more about the great migration journey of Monarch butterflies, find our article below:

The Extraordinary Monarch Butterflies

Monarch larva, milkweed

Monarch larva on its host plant

Native plants support species richness and insect abundances. Based on a study, researchers found that caterpillars reared on native host plants had higher survival rate and larger size (Yoon and Read, 2016). In addition, they found that plant communities invaded by nonnative species had significantly fewer insects from the lepidopteran group and less species richness.

When diversity of insects is low in the residential yards dominated by nonnative plants, the birds have to switch their diet to lower quality diet and suffer the consequence (Narango et al., 2018).

In the yards with more nonnative plants, spiders were more abundant than caterpillars. In these types of yards, the researchers found that Carolina chickadees had to switch their diet by eating more predatory arthropods, (such as caterpillars), than herbivorous insects (such as spiders) (Narango et al., 2018). They used the values of δ15N, or nitrogen isotope ratios, to assign trophic position of individual birds, where lower values showed the birds ate more herbivorous insects, whereas higher values showed the birds ate arthropods that are more predatory.


Carolina chickadee with its prey. Photo used with permission |image credit: Katherine Martin/Gold Biotechnology.

Based on the same study, yards with more nonnative plants do not provide enough high quality insect preys, so the reproduction and survival of Carolina chickadees decline. The researchers also discovered that yards with more than 70% native plants of plant biomass had greater reproductive success and sustainable population growth for the birds (Narango et al., 2018).

Are all nonnative plants bad?

Actually, not all nonnative plants are bad. Some ornamental nonnative plants introduced to a new area cannot reproduce or spread without our help. These ornamental plants are pretty, so they are more popular in residential yards than native plants.

Nevertheless, some nonnative plants can establish themselves in a new area, invade the native plant's communities, and disrupt the stable ecosystem. These types of nonnative plants can also cause the decrease of insect populations. In Oregon, the endangered Fender’s blue butterfly cannot find its host plant when the invasive grass outcompetes it, so it affects the butterfly’s fitness (Severns, 2008).

Japanese barberry

Japanese Barberry. Japanese barberry was introduced into the U.S. in 1875 as an ornamental plant. This invasive plant produces many seeds and germinates rapidly. It also changes soil chemistry, therefore it reduces native plant populations.

Occasionally, some non-native plants, which are not invasive, support the wildlife. For example, tamarisk shrubs were nonnative plants introduced in the US around the 1800s and then they became one of the nesting habitat of the endangered southwestern willow flycatcher bird.

To sum up, some ecologists suggested not to judge plants species based on their origins (Davis et al., 2011). What’s essential is to assess them based on their environmental impact rather than on whether they are natives. Therefore, before removing all nonnative plants in your backyard, investigate whether they are invasive and harmful for the environment.

So, what’s considered native plants for your area?

According to the U.S. Department of Agriculture, native plants are a part of the balance of nature occurring over thousands of years in particular areas, which include trees, shrubs, and vines. In addition, only plants found in certain parts of the U.S. before European settlement are considered as native.

Pagoda dogwood

Pagoda Dogwood. Pagoda Dogwood is a flowering plant, native to eastern North America. This plant produces fragrant flowers, which attracts pollinators, such as butterflies, bees and specialized bees from the genus of Andrena. In addition, it produces blue-black berries, which attract small mammals and birds. Photo used with permission |image credit: Janet Lensing/University of Kentucky, Department of Entomology.

When using the word native, we should include a geographic qualifier, for example, “native plants to Missouri”. To find out more about the native plant species for your local area, check out the Native Plant Finder tool.

The native plants adapted to the local climate conditions for a long time and now they live in harmony with other organisms in the same ecosystem. They are also crucial in supporting biodiversity that is important for the health and wellbeing of our environment.

blue flag iris

Blue Flag Iris. Blue flag iris is native to North America. The flowers attract birds, such as hummingbirds. It also attract pollinators, such as native bees and butterflies.

Therefore, consider to plant more trees that are native to your area or dedicate a space for some native plants in your yards. One way to find native plants for your gardens is by checking out the website of your nearest botanical gardens or arboretums. Oftentimes, these places host a plant sale event for native plants in the spring.

black walnut

Black Walnut. Black walnut is one of the most valuable native trees in North America. Its wood is commercially used for making furniture and its nuts are edible for us. Wildlife animals, including squirrels and a variety of birds eat the nuts. It also has many insects that devour its leaves, such as beetles and caterpillars of moths. Photo used with permission |image credit: Eldon Kroemer, Nebraska.


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