lec 29-30: Biological invasions

Question 1

what is a non-native species?

Answer 1

A species introduced outside of its natural (historical) range (i.e where it evolved)

no evolutionary history to the region

Question 2

what is a Biological Invasion

Answer 2

The spread and establishment (i.e forms a self-sustaining population) of a species into a region beyond its natural range

leaving it’s historic range boundary and entering an invaded range

Question 3

what is the process of biological invasion

Answer 3

(its a circle)
Introduction
(formation of self-sustaining population)
Establishment
(impacts often detected here)
Geographic spread
(natural or human-assisted dispersal)
Back to introduction

Question 4

What is an “invasive” species?

Answer 4

An introduced (alien) species that spreads rapidly (i.e a highly successful invader)

Question 5

What is the Great American Biotic Exchange

Answer 5

(around 3 million years ago) when North and south America connected by the Panama land bridge

• mammals moved north and south

A series of extinctions followed on both continents

Question 6

T or F: Species are being moved long distances to regions that they could never reach without human assistance

Answer 6

True

Question 7

What are Wallace’s Biogeographic Realms

Answer 7

There are 7:
narcotic
neotropical
Ethiopian
Palaearctic
oriental
Australasian

explains the distribution of animals and plants as a result of geographical changes

Question 8

(not a question) New Zealand

Answer 8

NZ is a good example of man-made importations of non-native species. NZ is now home to goats, cats, foxes, deer

Question 9

Is the antarctic spared from biological invasions

Answer 9

No! because humans go there and always carry with them organisms (like seeds under their shoes) So the Antarctic is also at risk from invasion

Question 10

T or F: Invasions are now occurring at unprecedented rates

Answer 10

TRUE

Question 11

How does the global (ship) transportation system contribute to biological invasions? (3 examples)

Answer 11

1. Unwanted stowaways
2. Organisms on ship hulls
3. Ballast water

Question 12

T or F: more or less 7000 species are carried in ships at any given time

Answer 12

TRUE

Question 13

What are the differences between natural (prehistoric) and human-assisted invasions?

Answer 13

1. The frequency of long-distance dispersal events is now very high
2. The number of species transported per event is now potentially large
3. The variation in mechanisms and routes of dispersal are now extremely large
4. Invasions between biogeographic realms are now common
5. the potential for synergies with other stressors are now very high

Question 14

T or F: Invasive species are a major threat to native biodiversity

Answer 14

TRUE

Question 15

what is the average contribution of invasions in animal extinctions

Answer 15

Gobal animal = 62%
Fish = 48%
mammal = 69%
bird= 60%
reptile= 57%

Question 16

T or F: Non-native consumers cause more damage to prey populations than do native consumers

Answer 16

TRUE

Question 17

what is the ecological distinctiveness hypothesis

Answer 17

the largest impacts are caused by species invading systems where no similar species exist

Question 18

T or F: Invasions can disrupt ecosystems, often in unpredictable ways

Answer 18

TRUE

Question 19

What is the synergistic relation between invasive mussels, warm temperature, botulism and waterfowl

Answer 19

The invasive zebra mussels -> Filtration activity -> improves water clarity -> Excessive growth of algea and plants-> Algal die-offs reduce the oxygen (also caused by warmer temperatures) -> promotes botulism bacteria -> consumed by zebra mussels -> consumed by round goby fish -> consumed by waterfowl -> waterfowl dies

Question 20

T or F: Invasions degrade ecosystem services and cause a broad range of socio-economic impacts

Answer 20

TRUE (i.e crop pests invasions)

Question 21

What should be done to reduce invasions? (4)

Answer 21

1. Create systems of early detection and rapid response at national and international scales
2. Develop better risk assessment methods for identifying and prioritizing high-risk invaders
3. identify and control emerging vectors and pathways
4. tighten regulations concerning trade in live organisms