Activity 3.3 Invasive Species

Activity 3.3 – Invasive Species

Use the information from environment Canada below to answer the following questions (type directly into the word document below each question). Use full sentences and put answers in your own words.

Marking: if student answers all questions thoroughly, 10/10. Check that they have included references for #7….you may want to check facts.

1)What is the difference between a native and alien (or introduced) species?

Native – occurs naturally in that habitat, Alien – has been brought into an area that is not their natural range

2)What is the difference between an alien species and an alien invasive species?

Invasive species are harmful to the ecosystem

3)Invasive species are a huge threat to biodiversity. What is the only threat to biodiversity that is bigger than invasive species?

Habitat destruction

4)Why do most introduced species not become invasive?

They are often not properly adapted to their new habitat.

5)What are the three factors that enable invasive species to thrive?

Higher rates of reproduction – it has been estimated that one Purple Loosestrife plant can produce 3 million seeds.
Fewer natural predators – newly introduced species are often free of predation and disease, two major factors that keep native plant and animal populations in balance.
Ability to thrive in different environments – most invasive alien species are generalists, meaning they can survive in a variety of different habitat types and climate regions.

6)What are the three categories of impacts invasive species can have? Give an example of each.

Societal, environmental and economic

7)Find the list of invasive species specific to BC in the information below. Pick ONE plant or animal and research the following information on the internet:
a) Where in BC is this invasive species found?

b) How is it thought to have been introduced?

c) What sorts of damage has it caused (list several).

****INCLUDE THE ADDRESSES FOR THE WEBSITES YOU OBTAINED YOUR INFORMATION FROM****

8)What are the two main categories of “pathways” to introduce species?
natural and man-made

9)Read about the many different pathways that are responsible for moving invasive species. How can individual’s actions help with some of these
- plant only native species in gardens
- clean boat hulls/motor props after use
- do not purposely transport organisms to new areas (ie live bait)

Alien Species

Courtesy: Environment Canada

What Are Alien and Invasive Alien Species?

Across the world, many species of plants, animals and even micro-organisms have moved beyond their native range and habitat only to become established in a completely new location. Sometimes species commonly found in one part of Canada become established outside their natural range in another region of the country where they have not historically been found. Most however, come from outside Canada and were relocated as a result of human activity.

Species that have become established in areas outside their natural range are known as "alien species". Generally, alien species do not pose a significant risk and many are even beneficial. However; when alien species are capable of causing significant harm to our environment, the economy or to society, they are referred to as "invasive alien species".

Canada has many examples of both alien species and invasive alien species. A few examples are shown below.
Alien Species / Invasive Alien Species
/ Black-footed spider / / Emerald Ash Borer
/ Common plantain / / Green crab
/ European hare / / Butternut Canker
/ Red-eared slider / / Giant Hogweed

Native Species

Native species are those species that are indigenous to a particular area or region. Typically, these species have evolved over thousands of years, adapting to their surroundings, and have become an important part of the local ecosystem.

Like most species, native species are constantly competing for resources. Changes to the climate, weather disturbances, fires, floods, the introduction of invasive alien species and human influences can have a significant impact on the growth or decline of a native population. Over time, some species may even be pushed out of a region or area altogether.

Growing or shrinking native species populations can have a big impact on local ecosystems. In some cases, these shifts can be very harmful. For example, the forest tent caterpillar (Malacosomadisstria) is a native species whose populations can sometimes grow so quickly that it will strip the leaves from large areas of hardwood forest. Even though this species often lives in balance with other species, its varying population size can cause considerable economic, environmental and social harm.

The Mountain Pine Beetle (Dendroctonusponderosae) is another native species that can cause devastation to its environment. Adult mountain pine beetles lay their eggs on the bark of a variety of different pine trees. After the eggs hatch, the larva feed on the phloem (inside bark area) which can ultimately kill the tree. Like the tent caterpillar, major increases in the beetle larvae population can seriously harm the local tree population.

The mountain pine beetle has coexisted with the pine forests of British Columbia for centuries, and although outbreaks have occurred, they have been short-lived and regional in area. Recently however, the Mountain Pine Beetle population has exploded causing unprecedented tree mortality and problems for forest industry.

Although the scale of this epidemic has never been experienced before, the mountain pine beetle is currently only impacting forests within its historic or native range. This situation is being closely monitored however and its status will be re-evaluated should the conditions change and it moves into areas where it is considered to be invasive.

Why Are Invasive Alien Species a Problem?

Introduction

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.

It takes the right conditions for an alien species to become established and grow. In fact, most introduced species do not become permanently established in their newly found environment. They either find the wrong type of conditions for survival, or there they are unable to produce enough offspring to maintain a viable population. For those species that are able to reproduce and survive, most never cause significant problems. They survive, spread and reproduce but generally do not pose a risk to Canada’s economy, environment or society.

Some introduced species however, are able to thrive and even flourish at their new location. They have the right biological properties that allow then to grow in numbers quickly. In addition, they are usually able to reproduce and spread quickly, often out-competing native plant and animal species for food water and space.

Invasive alien species generally share common characteristics which can make them difficult to control and contain, including:

Higher rates of reproduction – it has been estimated that one Purple Loosestrife plant can produce 3 million seeds.
Fewer natural predators – newly introduced species are often free of predation and disease, two major factors that keep native plant and animal populations in balance.
Ability to thrive in different environments – most invasive alien species are generalists, meaning they can survive in a variety of different habitat types and climate regions.

The impact of invasive alien species on native ecosystems, habitats and species is severe and often irreversible, and can cost billions of dollars each year.

Invasive Alien Species Impacts

Environmental Impacts

Can negatively impact biodiversity
Can cause species extirpation and even extinction
Can cause soil degradation, and erosion
Can alter fire cycles

Societal Impacts

Can cause disease
Can cause human or animal suffering
Can reduce land and water recreational opportunities

Economic Impacts

Control and management costs can be significant
Can reduce productivity in forestry, agricultural, and fishing sectors
Can cause export and import trade restrictions
Can reduce property values

The following are just some examples of invasive alien species impacts in Canada and abroad. Check regularly as this list will be continuously updated.

Table 1: Types of Species and their Impacts to Canada
Species / Type of impact (economic, environmental, societal) / Description of impact
Zebra Mussel
Dreissenapolymorpha / Environmental / Zebra muscles will infest almost every hard surface including rocks, boat hulls, and water intake pipes. They can even grow on the shells of our native clam species, reducing their ability to feed and as such increase mortality.
Japanese Knotweeds
Fallopia japonica & Polygonumcuspidatum / Environmental / Japanese Knotweed is a perennial shrub from Asia, often considered one of the most persistent of all weeds. Once established in disturbed areas or along stream banks, this highly invasive species can displace virtually all other types of vegetation.
West Nile Virus
Family: Flaviviridae / Social / The West Nile Virus originated in Africa and Europe. Since its discovery in North America, public health agencies have been waging an aggressive campaign to inform the public about the risks associated with contracting this disease.
Emerald Ash Borer
Agrilusplanipennis / Economic / The cost of eradication and control efforts associated with this invasive insect have totalled in the millions per year.

Global Impacts

Table 2: Types of Species and their Impacts Globally
Species / Type of impact (economic, environmental, societal) / Description of impact
Comb Jellyfish
Mnemiopsisleidyi / Economic / This small jellyfish, native to estuaries of eastern North and South America, was almost certainly exported to the Black Sea in ship ballast water. Since it was first discovered in 1992, it has single-handedly caused the collapse of the entire anchovy fishery, an industry once worth millions of dollars per year.
Brown Tree Snake
Boigairregularis / Environmental / This invasive alien species first introduced to Guam shortly after World War II, has caused immeasurable damage to the Island's ecosystem. The Brown Tree Snake has been directly linked to the extirpation of several native species of birds (8), lizards (3), and mammals (2 bats).
Water Hyacinth
Agrilusplanipennis / Social / Originally from the Amazon basin, this water plant has spread to many aquatic ecosystems around the world. Whole communities around Lake Victoria, Africa’s largest lake, have had to move to gain better access to open water and fish stocks.

Where Are Invasive Alien Species Found in Canada?

Introduction

According to the World Conservation Union, invasive alien species are the second most significant threat to biodiversity, after habitat destruction. No single region of Canada is immune from the potential for invasive alien species and many, if not all ecosystems are already experiencing some impact.

In their new ecosystems, invasive alien species become predators, competitors, parasites, hybridizers, and diseases of our native and domesticated plants and animals. The impact of invasive alien species on native ecosystems, habitats and species is severe and often irreversible.

In 2002, it was estimated that 24 percent of the species listed as “at risk” by the Committee on the Status of Endangered Wildlife could be threatened with extinction by invasive alien species.Some of the 90 native species on this list that are considered threatened by invasive alien species include ancient murrelets, island blue butterfly, golden paintbrush, tiger salamander, northern prairie skink, American chestnut, eastern flying squirrel and ginseng.

Similarly, in the Great Lakes, now home to more than 160 alien species, sea lamprey have been implicated in the extinction of the deepwater cisco, and zebra mussels have extirpated native mussels from some areas.

Clearly, invasive alien species are an increasingly important factor in the decline of native species in both aquatic and terrestrial ecosystems.

Invasive Alien Species in Terrestrial Environments

Many of Canada’s diverse terrestrial environments have been impacted by invasive alien species of plants, animals, insects and disease. Invasive alien species are most often found in or near urban areas, as well as throughout the settled landscape. Invasive alien species can also be found in many of Canada’s more remote regions including the arctic.

Here are just a few invasive alien species found in Canada’s terrestrial environments.

Table 1: Invasive Alien Species in Terrestrial Environments
Name of Species: / Description:
Japanese Knotweed
(plant) /

Large perennial plant native to China, Japan and Korea
Fast growing - can grow 2 or more meters in one growing season
This plant spreads primarily from discarded plant material or soil containing plant material
Found in many urban centres across Canada, and along some roadsides in Nova Scotia
Dense thickets will exclude other vegetation

Norway Rat
(mammal) /

A mammal species originally native to central Asia
A species that has followed human settlement patterns across all continents of the world
Prolific breeders
Can cause significant damage to crops, buildings, food stores
Poses a significant human health risk
Norway rats are found in every province except Alberta which has been waging an active campaign to keep them out for over 50 years

European Earwig
(insect) /

First noted in Newfoundland 1827 to 1835
Have since spread to all urban centres across Canada
Not directly harmful to humans
Nocturnal scavengers of decaying plant material, as well as leaves, flowers and fruit
Can become a significant pest of urban properties and may enter dwellings if populations are high enough

Butternut Canker
(disease) /

This disease is a serious threat to Butternut trees across its native range
Scientists are currently unsure of the origins of this fungus but hypothesize it was originally introduced from outside North America
Butternut is now a species at risk in Ontario
Cankers formed on stems and branches can cut off the movement of water and nutrients within the tree
Cankers on the main stem will most often kill the tree

Invasive Alien Species in Aquatic Environments

Many aquatic environments like rivers, lakes and oceans have been seriously impacted by invasive species. Whether these invaders were first released in ballast water discharged from a ship, or from fisherman emptying bait buckets containing non-native species, or even from people discarding unwanted aquarium plants and animals, the end result is the same: a new aquatic alien species that can upset the natural balance of the ecosystem in which they were released.

Here are just a few species currently found within Canadian waters:

Table 1: Aquatic Invasive Species in Saltwater Environments
Name of species: / Description:
Green Crab /

Also known as the "cockroach of the sea"
Was first introduced to the waters off Cape Cod over 100 years ago
It had spread to the waters of New Brunswick by the 1950’s and British Columbia in 1998
Occupies the same habitat as native crabs, clams, oysters, and mussels

Tunicates /

Invasive tunicates or ‘sea squirts’ are a type of filter-feeding animal that grow on submerged stationary objects
There are five know invasive tunicate species affecting the aquaculture and fisheries of Canada’s east and west coasts

Table 2: Aquatic Invasive Species in Freshwater Environments
Name of species: / Description:
Chinese mitten crab /

This crab spends much of its lifecycle in fresh water environments
Canada has no native freshwater crab species
Although first discovered in Lake Erie in 1965, it has not been able to become established in the Great Lakes, probably due to its need for both fresh and saltwater environments when completing its lifecycle
This species does represent a significant threat to St. Lawrence River and its many tributaries

Zebra Mussel /

First discovered in the Great Lakes around 1986
Have significantly change the nature of the lake bottom, affecting fish habitat and spawning
Mussel populations often dominate near shore zones changing natural process such as nutrient flow into deeper waters
Mussels also excrete nutrients creating an environment that may be linked to water quality problems, such as algal fouling on rocky shorelines, off-tastes in drinking water and lethal outbreaks of botulism in wildlife, especially during warm water periods

Round goby
(fish) /

Introduced to the St. Clair River in 1990 probably through ballast water from ships originating from southern Europe
Have sincecolonized all five Great Lakes
Have impacted native fish populations
In Ontario, it is illegal to possess living round goby or to use them as bait
Can spawn more then once per year

Invasive Plants and Animals in BC