Galatowitsch Sectipn 2.2-2.3

Question 1

What are the 6 drivers of ecological change (ie. stressors) that the author discusses?

Answer 1

Habitat conversion - change of terrestrial or aquatic land for cultivation

Pollution - natural or unnatural materials being added to ecosystems from industry etc.

Overexploitation - hunting/fishing etc.

Species introductions - redistribution of species throughout world by humans

Climate change

Natural drivers - natural variations in conditions (natural disturbances etc.)

Question 2

How does habitat conversion drive ecological change?

Answer 2

Through things like erosion, sedimentation, flow changes, habitat removal

Question 3

How does pollution drive ecological change?

Answer 3

Through sewage additions, nitrogen and phosphorous fertilizers, accumulated manufactured materials

Question 4

How does overexploitation drive ecological change?

Answer 4

Direct removal of species, inability for populations to sustain themselves, reduction in both commercial and non-valuable species (eg. Fishing nets)

Question 5

How do species introductions drive ecological change?

Answer 5

Invasive species
Crop pests
Cause biotic homogenization (globally widespread species)

Question 6

How does climate change drive ecological change?

Answer 6

Distribution of water, functioning of organisms, available resources, change in disturbance regimes, species migrations

Question 7

How do natural drivers affect ecological change?

Answer 7

Changes in food availability, change in enemy abundance, vegetation changes, changes in habitat suitability

Question 8

What are the 6 ecological effects (impacts) of the stressors the author discusses?

Answer 8

Population declines (vulnerability increases with declines)

Effects of habitat fragmentation (results in genetic isolation and extinction)

Spread of introduced species (outcompete/predate on natives, change soil composition)

Species interactions (loss of mutualistically important species (predator prey relationships and keystone species etc.)

Disturbances and succession (natural and human caused can change soil nutrients, biodiversity, reset succession, and regulate energy)

Ecosystem decline- multiple stressors cab result in multidimensional cause of decline