Biology 3709 - Alien Invasive Species

8/6/2019 Biology 3709 - Alien Invasive Species

http://slidepdf.com/reader/full/biology-3709-alien-invasive-species 1/14

Alien

InvasiveSpecies

Matthew&

Zack



� Non-native microorganisms, plants andanimals which adversely affect the areas they

invade. Debate on what actually constitutes a native species.

General agreement that a native species has fullyadapted to an areas natural environment.

� They do not always have negative effects.

May simply have invasive species livingpeacefully in a new environment.

Sometimes defined as an exotic species.



� Can be stowaways on any transport vesseland get dropped off in f oreign territory.

� They can be intenti

onally intr

oduced byprivate companies.

� Can be unintentionally shipped on freshproduce or other exotic resources.

� Man made canals and other alterations to theenvironment can open up opportunities f ororganisms to invade new areas.

� Animal vectors are also common, such as

migrating birds.



� They lack natural predators.

� They can introduce f oreign pathogens and

wipe out native species.� They can easily out-compete native species

f or resources and space. Native species have no built-in mechanisms to deal with

invasive species.

� Have high reproduction rates and can thrivein different environments.



� They easily disrupt f ood webs (e.g. outcompetition).� They can f orm hybrids with native species,

ultimately causing lo

sso

f the native species.� They are huge economic antagonists, which take

lots of time and money to regulate.

E.g. zebra mussels costs ~$100 million/year to regulate

due to

damage to

ships, pipelines, and aquaculture.



� Since the island of Newf oundland is

completely surrounded by ocean, any species

which migrate here (non aided by humans)must be able to tolerate salt water or cross by

air/ice.

�

With increased human travel ito

pens upavenues f or the species to tag along, such asthe Zebra mussel which hosts on ship hulls or

ballast tanks.



� Second only to habitat loss, invasive alien speciesare the most significant threat to native species and

bio

diversity.� Newf oundland and Labrador Wild Life Act (1992),

Restricts the import, and possession of non-nativewild life into the province, or onto the island portiono

f the pro

vince fro

m Labrado

r. Pro

hibits the releaseof any wild life that has been imported or that hasbeen propagated from imported stock onto thenatural landscape.



� Over 35% of plant species in NL are alien

invasive.

� Newf oundland and Labrador 's flora of approximately 1,500 vascular plant species

comprises perhaps 1,000 native species and500 naturalized species.The latter were

brought here intentionally or accidentally andhave flourished.



� One of the most harmful of invasive speciesinNewf oundland is the moose.

�

Intro

duced in the early 1900s the moo

se hasspread throughout the island, bred withoutcheck and is now inflicting serious damage inour national parks and many parts of rural

Newf oundland. A voracious browser, moosehave stripped tree branches as high as theycan reach and munched native shrubs downto their crowns.



� The snow shoe hare is also a non-native

island species.

� It too browses native vegetation, but is f ondof young shoots and seedlings.The result is a

dramatic change in boreal f orest recovery,age structure and understory species.



� OysterThief (Codium fragile tomentosoides).� A green alga from Japan, first appeared in

easternC

anada in 1989 in so

uthernNo

vaScotia. It also appeared in the Gulf of St.Lawrence in 1996. Uproots eelgrass whichprovides shelter and reproductive and

feeding habitat f or fish, molluscs andcrustaceans.� May overtake kelp beds. Bad f or shell fish

industry.



� Green crab, (Carcinus maenus).

� Native to Baltic and eastern Atlantic.Travels

on ships hulls, ballast tanks, ect. It feeds onbivalves including clams, oysters, mussels,

ect.



� Trying to kill invasive species is highly

ineffective.Natural predators are the best at

controlling their numbers.� Mussel aquaculture is a common vector of

invasive species transport (e.g. tunicates andthe green crab).

� Eventually an invasive species will becomeless of a threat to its new area, due to its

incorporation into natural f ood webs and

native species adjusting to its presence.



� http://www.invasivespecies.gc.ca/english/Lin

kSearch.asp?x=1&f ormAction=SubjectArea

� Coulatti, R. & MacIsaac,H. (2004). A neutralterminology to define invasive species.

Diversity and Distributions. 135-141.

Biology 3709 - Alien Invasive Species

Documents

Transcript of Biology 3709 - Alien Invasive Species