LAB || Native and Invasive Species

Ecosystem

A biological community of interacting organisms and their physical environment.

Role of plants in ecosystems

Plants make up the majority of organisms in ecosystems and provide food and energy for animals directly or indirectly.

Food webs

Complex networks of feeding relationships that connect plants and animals within ecosystems.

How ecosystems develop

Ecosystems develop over time into functional systems where species rely on one another.

Native species

A species that evolved naturally with the soils, climate, and organisms of a particular ecosystem and was not introduced by humans.

Natural expansion of species

When organisms gradually spread to new areas on their own; this does not necessarily make them non-native.

Native plants increase biodiversity

Native plants increase the number of species that can survive in an ecosystem.

Native plants as insect hosts

Native plants serve as hosts for many insect species.

Native plants as habitat

Native plants provide habitat for animals.

Native plants as food sources

Native plants produce leaves, fruits, and seeds that serve as food for ecosystems.

Invasive species

A non-native species whose introduction causes or is likely to cause environmental, economic, or human health harm.

Types of invasive organisms

Plants, insects, diseases, mammals, birds, reptiles, amphibians, crustaceans, nematodes, fish, and arachnids.

Major effect of invasive species

They compete with native species.

Second leading cause of species endangerment

Invasive species (after habitat loss).

How invasive species affect ecosystems

They weaken ecosystems and alter biodiversity.

Evolutionary disruption by invasives

They interfere with the natural ways that communities evolve.

Human impacts of invasive species

They affect recreational, agricultural, and other human uses of land.

Economic cost of invasive species

High costs are required to control or remove them.

Common invasive plant characteristic: reproduction

Produce many seeds that disperse easily.

Common invasive plant characteristic: growth

Grow and mature rapidly.

Common invasive plant characteristic: lifespan

Often live a long time.

Common invasive plant characteristic: adaptability

Adapt easily to many habitats.

Reason invasive plants succeed: predators

They often lack natural predators in the new environment.

Reason invasive plants succeed: disturbed soil

Many thrive in disturbed soils.

Reason invasive plants succeed: climate similarity

The climate in the new location is similar to their native habitat.

Intentional introduction of invasive plants

About 85% were intentionally introduced for ornamental or landscaping purposes.

Agricultural introduction of invasive plants

About 14% were introduced for agriculture.

Exotic vs invasive plants

Most non-native plants are NOT invasive.

Probability of plant invasion

Out of 100 introduced species, about 10 become harmless exotics and 1 becomes invasive.

How pests are introduced

Through the import and distribution of exotic plants that carry parasites.

Animal introductions

Animals may be released intentionally or accidentally into the wild.

Example of animal introduction

Fish released into lakes by aquarium dumping or stocking fishing sites.

Chinese Privet

An ornamental shrub introduced in the 1800s that forms dense thickets and shades out native plants.

Japanese Honeysuckle

An ornamental vine introduced in the 1800s that girdles saplings and forms dense canopy mats.

Kudzu

A fast-growing vine introduced for erosion control that smothers and kills other vegetation.

Chinese Wisteria

An ornamental vine that girdles trees and shrubs and changes forest understory light conditions.

English Ivy

A vine introduced as groundcover that blocks sunlight from host trees and weakens them.

Nandina (Sacred/Heavenly Bamboo)

Shade-tolerant ornamental plant that invades forests and outcompetes native plants.

Callery Pear (Bradford Pear)

A pear tree introduced for disease resistance that spreads aggressively and produces foul-smelling flowers and fruit.

Hemlock Woolly Adelgid

An invasive insect that feeds on and kills Eastern Hemlock trees.

Emerald Ash Borer

An invasive beetle whose larvae bore into ash trees and kill them.

Biological control question

Scientists are testing whether introducing insects can control Emerald Ash Borer populations.

Goldfish as invasive species

Released pets or food fish that compete with native fish for resources.

House Sparrow

An aggressive bird introduced to the U.S. that takes nesting sites and food from native birds.

Wild Pig

Escaped or introduced livestock that damage crops, forests, and ecosystems and spread disease.

Weed

An unwanted wild plant.

Native plant definition

A plant that evolved naturally with the soils, climate, and organisms of a specific region.

Exotic plant

A plant species not native to the continent where it is found.

Cultivar

A plant selected for desirable characteristics like flower size, leaf color, or growth form.

Hybrid

A plant produced by crossing two plant lines or species to combine traits from both parents.

Invasive plant definition

An introduced plant that spreads rapidly and disrupts plant communities or ecosystems.

Non-native plant

A plant introduced by humans to a new location where it did not previously occur.

Naturalized plant

A non-native plant that can reproduce and maintain populations without human assistance