Lecture 16 Invasive species

Question 1

What prevents species from dispersing globally (2)

Answer 1

*Barriers are in the eye of the beholder; what is a barrier to some species may not be one to another (ex mountains may limit plant distribution, but not birds)
*Barriers to dispersal are what creates regions of biodiversity

Question 2

Human effect (3)

Answer 2

*Species are being transported across these barriers at an increasing rate due to human movement and commerce.
*50,000 times greater rate of spread than by natural dispersal in some cases
* major vectors are planes, ships and humans

Question 3

what are invasive species (Definition and 5 kinds)

Answer 3

Species introduced to regions outside of their historic native range

1. exotic species : From another part of the world
2. Introduced species: implies introduction but are not a threat
3. Alien species : implies introduction to a particular ecosystem
4. Invasive species : implies exotic and a threat to native species
5. Non-native species: introduced by humans on purpose or by accident, including species that crossed into a new zone as a result of human-caused environmental damages

Question 4

Non-native species in the boreal zone of Canada (6)

Answer 4

Native species diversity generally decreases with increasing latitude
* Expect non-native species diversity to have a similar pattern
*Extreme climate, low biodiversity, and poor resource availability are hostile to introduced species
* Much of the forest remains undisturbed, reducing susceptibility to exotics
* Researchers aren’t looking
*Over the past 500 years, at least 1180 non-native species have colonized the boreal zone of Canada

Question 5

non-native species in Canada (3)

Answer 5

*58% of non-native plant species were deliberately introduced to Canada
*41-67% of insects introduced directly, often for biocontrol; others arrived in the USA first, then spread to Canada.
*introduced as biocontrol, for better soil, as crops etc.

Question 6

biological control (4)

Answer 6

*For many decades, non-native insect predators and parasitoids have been introduced to Canada and released to control native and non-native pests of trees and crops

• many of these introduced species have become established
• some introduced biocontrol agents incorporate native hosts into their diet and cause serious reductions in populations of native species
• the impacts of non-native insect predators and parasitoids on native boreal fauna have not received any attention

Question 7

Eurasian Milfoil

Answer 7

Aka the Zombie plant. Aquatic weed that forms a thick mass of stems under water, which get caught in boat propeller. These stems also reduce native plant populations and impact fish habitats. Primary spread when boats move between lakes

Question 8

round goby

Answer 8

reduces native fish populations by eating their eggs such as lake trout and smallmouth bass. Spread when used as bait or when released upstream

Question 9

Spiny waterflea

Answer 9

Feed on zooplankton in lakes. Can alter the food chain and effect fish populations. Large numbers form jelly like masses that clog fishing gear. Spread when bait buckets are moved between lakes.

Question 10

Whirling fish disease

Answer 10

invasive parasite that infects salmon and trout. It impairs the fish’s nervous system causing it to swim in a spiral pattern. Can spread from infected bait, or on boats

Question 11

zebra mussels

Answer 11

small freshwater mussels that can completely cover the bottom of lakes, impacting fishing, native mussels and water quality. Usually spread when they attach to moats

Question 12

St. Lawrence seaway (3)

Answer 12

*Opened in 1959 with water from the 7 seas of the world
*Ballast water from ships (water inside ship to keep it stable) is dumped into the surrounding area
*the largest single source of invasive species in the world