L15-Research in action

Question 1

What are the different types of facilitation?

Answer 1

Types of facilitation:
• Habitat amelioration-eg. algae decrease temp,
• Refuge from predators/herbivores-eg. mangroves hiding fish
• Prey or resource (e.g. nutrient) enhancement
• Provision of structural habitat

Question 2

What is Facilitation?

Answer 2

Individual(s) improve local conditions to increase the
performance of other individual(s)

Question 3

Why are positive interactions important?

Answer 3

important in shaping marine systems

Question 4

How can facilitation occur?

Answer 4

Can be both interspecific or intraspecific

Question 5

Facilitation-competition continuum

Answer 5

Facilitation and competition occur simultaneously
• Relative balance shifts along a continuum

Question 6

Facilitation-competition continuum depend on several factors

Answer 6

• Density-dependent-total species
• Frequency-dependent-relative density
• Distance to neighbours-eg distance from adults(juveniles do better close adults better further away
• Species traits (e.g. age, size, morphology)
• Environmental conditions (e.g. stress)

Question 7

Stress-Gradient Hypothesis (SGH)

Answer 7

as environmental stress increases so will the presence of facilitation. Neighbours benefit more from amelerating enviromental stress
evidence is mixed

Question 8

What dis Maestre et al. (2009) suggest for Stress-Gradient Hypothesis (SGH)?

Answer 8

• Facilitation peaks under intermediate stress
• Competition predominates at extremes

hum shaped as resource avaiblity gets to low compettion starts to ramp up

Question 9

Michalet et al. (2014) Stress-Gradient Hypothesis (SGH)

Answer 9

• Facilitation peaks under intermediate stress
• Extreme stress negatively affect organisms and overwhelms species interactions

species interations stoping being important affter a point as enviroment only important factor

Question 11

Ecological Theory

Answer 11

Concepts, predictive and mathematical models to explain pattern and process in ecological systems

Question 12

Ecological restoration

Answer 12

Practice of actively restoring degraded ecosystems

Question 13

Restoration Ecology

Answer 13

Developing and testing theories to guide restoration practices

Question 14

How can facilitator species help restore entire enviroment

Answer 14

if facilitators are brought back could aid recover otyher species

Question 15

What is nurse plant?

Answer 15

plant that makes habitat underneath them more favourible

useful for restoration

but species/context depenedent

Question 16

How does planting salt marsh togther vs apart?

Answer 16

more succesful with same amount of plants using clumped due to facilitation.

Question 17

What has been the effect of plantaing marcroaglae?

Answer 17

Mixed restoration success:

• High recruitment at one restored site (and increased nurse effects)
• But no recruitment at second site

Re-established at only 50 % of sites

• Fish herbivory reduces algal canopies
• Erodes nurse effects?

Question 18

What is Hormosira banksii?

Answer 18

Dominant on intertidal reefs in Southern Australasia Important ecosystem engineer Susceptible to disturbance Slow natural recovery

• Limited dispersal
• Recruitment supressed by other species (e.g. ephemeral algae, grazers)
• Lack of adult canopy to facilitate recruitment Target for intertidal restoration!

Easy to spawn and settle = good model system

Question 19

is there evidence for nurse effects What is Hormosira banksii?

Answer 19

nurse effects strong not polluted

Nurse effects become neutral (collapse) at polluted sites

Pollution negatively affects propagules and overwhelms benefits of canopy

Question 20

Why do nurse effects collapse at polluted sites?

Answer 20

three pssoible explantations

Toxicity effects

Increased grazing

Increased competition