L15-Research in action Flashcards
What are the different types of facilitation?
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
What is Facilitation?
Individual(s) improve local conditions to increase the
performance of other individual(s)
Why are positive interactions important?
important in shaping marine systems
How can facilitation occur?
Can be both interspecific or intraspecific
Facilitation-competition continuum
Facilitation and competition occur simultaneously
• Relative balance shifts along a continuum
Facilitation-competition continuum depend on several factors
- 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)
Stress-Gradient Hypothesis (SGH)
as environmental stress increases so will the presence of facilitation. Neighbours benefit more from amelerating enviromental stress
evidence is mixed
What dis Maestre et al. (2009) suggest for Stress-Gradient Hypothesis (SGH)?
- Facilitation peaks under intermediate stress
- Competition predominates at extremes
hum shaped as resource avaiblity gets to low compettion starts to ramp up
Michalet et al. (2014) Stress-Gradient Hypothesis (SGH)
- 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
Ecological Theory
Concepts, predictive and mathematical models to explain pattern and process in ecological systems
Ecological restoration
Practice of actively restoring degraded ecosystems
Restoration Ecology
Developing and testing theories to guide restoration practices
How can facilitator species help restore entire enviroment
if facilitators are brought back could aid recover otyher species
What is nurse plant?
plant that makes habitat underneath them more favourible
useful for restoration
but species/context depenedent
How does planting salt marsh togther vs apart?
more succesful with same amount of plants using clumped due to facilitation.
What has been the effect of plantaing marcroaglae?
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?
What is Hormosira banksii?
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
is there evidence for nurse effects What is Hormosira banksii?
nurse effects strong not polluted
Nurse effects become neutral (collapse) at polluted sites
Pollution negatively affects propagules and overwhelms benefits of canopy
Why do nurse effects collapse at polluted sites?
three pssoible explantations
Toxicity effects
Increased grazing
Increased competition
