Lecture 8 JD

Question 1

Conservation biology

Answer 1

Conservation biology is a multidisciplinary science that has developed to address the loss of biological diversity
• It combines ecology, genetics, evolution, biogeography
• Knowledge of biotic interactions can aid conservation efforts
• Examples include the addition or removal of predators, altering competitive interactions, restoring mutualisms

Question 2

Artificial manipulations of herbivore pressure can

Answer 2

aid conservation of species and habitats

Question 3

Herbivory

Answer 3

can have positive and negative economic impacts, so understanding plant-herbivore interactions is important not just for understanding environmental health but also for human livelihoods

Question 4

Deer fencing in Killarney national Park

Answer 4

Oak woodland – higher density and taller saplings in fenced plots

Yew woodland – higher density and taller saplings in fenced plots

Question 5

Ecological restoration is the

Answer 5

process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed.

Question 6

Ecological restoration can be a

Answer 6

“top-down” or “bottom-up” process

Question 7

Yellowstone is the largest National park in the US “lower 48”

Answer 7

Mountain wilderness comprising alpine tundra, montane forest & grassland, many hot springs
• Bison, moose, elk, pronghorn antelope, wolverine, grizzly bear, black bear, mountain lion … but from 1926, no wolves
• Through the 20th century, expansion of grasslands, loss of woodlands
• Wolves reintroduced, beginning in 1995

Question 8

Wolves reintroduced

Answer 8

Reintroduction of wolves was correlated with dramatic ecosystem changes …
• … firstly a significant declines in elk numbers

Browsing damage to trees declined
• Aspen, Cottonwood and Willow trees all increased in size and abundance
• Beaver and Bison numbers increased

Question 9

Transition

Answer 9

Ecosystem complexity and diversity increased during transition from heavily grazed grassland into woodland
• Return of apex predator initiated a cascade of impacts across trophic levels and among species at each trophic level

Question 10

Biological control of invasive species

Answer 10

An introduced species which becomes established in natural or semi-natural ecosystem or habitat, is an agent of change, and threatens native biological diversity
• Introduced species can have significant environmental (e.g. species extinctions), economic (e.g. cost of control) and human health impacts

Question 11

Biological control

Answer 11

is an environmentally sound and effective means of reducing or mitigating pests and pest effects through the use of natural enemies.

Question 12

Japanese knotweed

Answer 12

(Fallopia japonica)

Question 13

Ornamental Gardening

Answer 13

First recorded in the wild 1902

Within Environmental Tolerance Limit – similar climate and soils – same biome/ecoregion

Question 14

Impact

Answer 14

• Altershabitat,reduces diversity
• Winterdieback makes riparian areas vulnerable to erosion
• Can cause damage to property

Question 15

Enemy release hypothesis:

Answer 15

invasive species, on introduction to a new region, experience a decrease in regulation by natural enemies, resulting in a rapid increase in distribution and abundance

Question 16

Physical removal

Answer 16

problematic due to reproduction by fragmentation

Question 17

Chemical control by systemic herbicide

Answer 17

glyphosate

Question 18

Biocontrol by specialist herbivore

Answer 18

Knotweed psyllid Aphalara itadori

Question 19

Biocontrol

Answer 19

Atophalara itadori was found be specialized to knotweeds, with only very low occurrence of development on a small number of related non-target plant species

Question 20

Biological control of invasive species – a cautionary tale!

Answer 20

The cane toad (Rhinella marina) was intentionally introduced to Australia to control the greyback cane beetle (Dermolepida albohirtum)

Question 21

102 toads were obtained from Hawaii and bred in captivity to increase their numbers until they were released into the sugar cane fields of the tropic north in 1935.

Answer 21

The toads could not jump very high and so were unable to eat the cane beetles which stayed on the upper stalks of the cane plants.

Question 22

However

Answer 22

the toad thrived by feeding on other insects and soon spread very rapidly; it took over native amphibian habitat and brought foreign disease to native toads and frogs, dramatically reducing their populations.

Question 23

When it is threatened or handled

Answer 23

the cane toad releases poison from parotoid glands on its shoulders; native Australian species such as goannas, tiger snakes, dingos and northern quolls that attempted to eat the toad were harmed or killed.