Week 4: Invasion and Restoration

Question 1

species affected by invasive species

Answer 1

70% of threatened species impacted by invasive species
Invasive plants affect 45% of threatened species

Question 2

stages of invasion

Answer 2

Transport over geographic barriers (management —> prevent)
Introduction by captivity or cultivation (prevent —> eradicate)
Establishment - survival and reproduction; invasion failure? (Eradicate —> contain)
Spread - dispersal and environmental (containment —> mitigation)

Question 3

managing invasion and impacts

Answer 3

Clear objectives
Consider impacts, feasibility, benefits and costs
Conflicting conservation goals
Increasing resilience
Unintended consequences

Question 4

driver

Answer 4

superior competitor so reduce competitive advantage

Question 5

passenger

Answer 5

better tolerates stressors or dispersal barriers so remove stressor or barrier

Question 6

biological levels of invasion

Answer 6

Individual - effect on performance or behaviour
Genetic - altered gene flow, natural selection or hybridisation
Population - altered abundance, distribution and growth
Community - altered biodiversity, food web structure
Ecosystem - changes in resources, rates of acquisition and disturbance regimes

Question 7

assessing impact of invaders equation

Answer 7

I = R x A x E

I = impact
R = range size of invader
A = average abundance across range
E = effect of invader (per capita/per unit biomass)

Question 8

site restoration goals

Answer 8

Restoring composition, structure, function and heterogeneity
Rare or unpredictable events such as fire or heavy rainfall may be critical

Question 9

fundamental objectives

Answer 9

Fundamental objectives = outcome goals
What are we trying to achieve ecologically

Question 10

mean objectives

Answer 10

Mean objectives = process goals
What work needs to be done?

Question 11

what are we aiming for?

Answer 11

Return to historic state
Maintain/return to reference state
Maintain/restore functioning and resilient ecosystems
Healthy novel ecosystems
Can almost never aim for pristine

Question 12

landscape reconstruction

Answer 12

Biodiversity enhancement and persistence at landscape scale
Whole landscape change, networks of restored sites
Reconstructing landscape function, native vegetation distributions, sustainable agricultural systems, resource use change
Often long timeframes

Question 13

spatially explicit planning

Answer 13

Combines models of habitat requirements with spacial conservation planning tools
Provides a schedule for revegetation
Objective - persistence of species increases over time
Accounts for habitat requirements, sensitivity to fragmentation and time for resources to develop
Assumes habitat requirements well known and restoration will work

Question 14

restoration process

Answer 14

Set objectives and performance measures
Identify barriers and/or thresholds
Identify actions to overcome barriers/thresholds
Implement and monitor