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 range2)What is the difference between an alien species and an alien invasive species?Invasive species are harmful to the ecosystem3)Invasive species are a huge threat to biodiversity. What is the only threat to biodiversity that is bigger than invasive species?Habitat destruction4)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 economic7)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-made9)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

http://www.ec.gc.ca/eee-ias/Default.asp?lang=En&n=C4637128-1

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

Canada has many examples of both alien species and invasive alien species. A few examples are shown below.

Alien Species Invasive Alien Species

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.

© Kenneth E. Gibson, USDA Forest Service, Bugwood.org

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 (Malacosoma disstria) 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.

© Erich G. Vallery, USDA Forest Service - SRS-4552, Bugwood.org

The Mountain Pine Beetle (Dendroctonus ponderosae) 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

Dreissena polymorpha

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 & Polygonum cuspidatum

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

Agrilus planipennis

EconomicThe cost of eradication and control efforts associated with this invasive insect have totalled in the millions per year.

Global ImpactsTable 2: Types of Species and their Impacts Globally

Species

Type of impact (economic,

environmental, societal)

Description of impact

Comb Jellyfish

Mnemiopsis leidyi

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

Boiga irregularis

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

Agrilus planipennis

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 EnvironmentsName 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

Table 1: Invasive Alien Species in Terrestrial EnvironmentsName of Species: Description:

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 EnvironmentsName 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

Table 1: Aquatic Invasive Species in Saltwater EnvironmentsName of species: Description:

aquaculture and fisheries of Canada’s east and west coasts

Table 2: Aquatic Invasive Species in Freshwater EnvironmentsName 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 since colonized 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

Courtesy: Invasive Species Council of BChttp://www.bcinvasives.ca/invasive-species

-Blueweed Canada Thistle Common tansy

Giant hogweed Gorse Hawkweeds

Himalayan Blackberry Hoary Alyssum Hound’s-tongue

Leafy spurge Knotweeds

Marsh Plume Thistle Oxeye daisy Purple Loosestrife

Rush skeletonweed Scentless chamomile Scotch broom

Spotted & Diffuse Knapweed Sulphur Cinquefoil Tansy ragwort

Yellow Flag Iris

Common Carp Didymo or “Rock Snot” Eastern grey squirrel

European Cottontail Rabbit Largemouth Bass New Zealand mudsnail

Rusty Crayfish yellow perch European fire ant

Zebra and Quagga Mussels

How Do Alien Species Get in Canada?

Introduction

Every species has a natural geographic area in which it is considered part of the native flora and fauna that make up the biodiversity of the region. Some species have a very small geographic range, while others may be found over multiple provinces or even one or more continents.

“Alien” species are those species that have moved outside their natural range into an area where they would not normally be found. One of the best opportunities we have to reduce the impact of invasive alien species is to prevent them from becoming established in the first place. To do this, we need to understand how they manage to move, or be moved, outside of their native range.

Natural Movement

Between approximately 12 and 80 thousand years ago, there were periods of time when much of North America was covered by ice. During these periods, plants and animals were pushed well beyond their natural range by the advancing ice and the changing climate.

When the climate warmed, and the glaciers began to recede, these same species slowly followed the glaciers north, and established new habitat. At the same time, the sheer volume of ice at the north and south poles caused a significant decrease in sea level exposing a land bridge between Alaska and Russia. It is thought that many mammal species moved from Asia to North America at this time.

While the native range of any species may change naturally with changes in climate and landform, they do so very slowly, often taking many hundreds if not thousands of years.

Unnatural or Human-assisted Movement

The problems we are experiencing today with invasive alien species are for the most part caused by unnatural species movement where a plant, animal insect or disease organism is moved outside its natural range into an area or ecosystem that they wouldn’t normally be able to get to on their own.

Human activity has been, and remains today, the primary means by which new species enter Canada. Throughout time, humans have both intentionally and unintentionally introduced species into new environments.

Figure 1. The cumulative number of species introductions into Canada since early 1600's.

The graph above demonstrates how over time the cumulative number of new species entering Canada has increased at what appears to be an exponential rate.

For Canada’s early settlers, bringing in new species was seen as a way to survive and adapt to their new surroundings. They brought various plants and animals, including some of the agricultural crops we depend on today like corn, wheat and potatoes. Some species were also unintentionally introduced – brought in as stowaways on the ships that brought people and supplies. The number of new species introductions started to grow substantially around 1900. Since that time, increased global trade and travel has led to a dramatic increase in the number of new introductions over the past several decades.

European Buckthorn (Rhamnus cathartica L) was brought to North America as an ornamental shrub in the late 19th century. It is now a serious invader of many woodlands in north eastern United States and south eastern Canada.

Early sailing vessels coming to North America used soil or rocks as ballast to stabilize the ship as it crossed the open ocean. This ballast was often replaced with a cargo of wood, fur or fish for the return journey to the home port. New species of insects and plants were introduced in this way.

Pathways

For invasive species, the term “Pathway” is used to describe the means by which a species travels from its natural habitat into a new one. A pathway can be either natural or man-made. Natural pathways like wind and water currents account for very few of the new species introductions. The vast majority of new species introductions are caused by humans. There are also distinct pathways for aquatic and terrestrial species.

Aquatic Species Pathways

Seven major pathways for the transport of aquatic invasive species have been identified.

1. Shipping

Many species have been introduced to the Great Lakes and other water bodies through shipping. Ballast water discharge and hull fouling have been responsible for such species introductions as zebra mussel, spiny water flea, and the green crab. 

Ballast water being discharged in port

2. Recreational and Commercial Boating

Pleasure craft and commercial boats and barges can inadvertently help spread invasive species around Canadian waters. Many of these vessels sit idol in their home harbour for long periods of time allowing species to grow and accumulate on their undersides; if these boats are then moved to a new and uninfested port, invasive species can be introduced into those water ways. Zebra mussels area a good example of this.

Eurasian Watermilfoil is a serious invader of fresh water ecosystems; even a small segment of this species can infest new waterways.

3. Live Bait

Live bait used for fishing and released into Canada’s lakes and rivers has been responsible for the movement of several species. The rusty crayfish is one example of a species that was introduced to many water bodies through live bait release; this species, native to Ohio, Kentucky and Tennessee has spread to many northern lakes and rivers.

4. Aquarium and Water Garden Trade

Aquariums and water gardens are popular hobbies for many Canadians. Unwanted fish and plants however, can be a source of invasive species introductions.

Yellow Floating Heart is an invasive aquatic plant that was originally introduced as a water garden species.

5. Live Foodfish

Many species of fish are imported live for food. If released into the wild, some of these species could become invasive.

6. Unauthorized Introductions

Native fish species have been purposely released into water bodies where they don’t belong. In some cases, these introductions have caused significant harm to the existing ecosystem.

7. Canals and Water Diversions

The construction of canals and water diversions has allowed species to move into new water bodies where they do not belong. Perhaps the best known case is the sea lamprey that moved into the upper Great Lakes once the Welland Canal was opened.

Terrestrial Species Pathways

Terrestrial invasive species are introduced and move around in a number of ways.

1. Cargo Transport

The increase in global trade has led to an increase in cargo shipments from all over the world – many thousands of cargo containers are brought into Canada each month. These containers sometimes contain living plants and animals and insects that build new homes here in Canada; these become invasive alien species.

2. Horticultural Planting

Many varieties of garden plants and herbs are imported into Canada. While the majority of these species do not pose a significant risk, some do, and several well known invasive species have escaped the confines of the garden to become a serious problem.

English ivy is one plant that has escaped to become a serious problem outside the confines of the garden.

3. Accidental Release

A number of terrestrial species have escaped captivity to become invasive.

4. Fire Wood Movement

Although not responsible for new introductions, some invasive insect species can be introduced to new (uninfested) areas through the transport of firewood, Christmas trees, and other wood products.

The emerald ash borer is a destructive invasive pest of ash trees. Firewood movement has contributed to its range expansion in Ontario.