BIO 475 Lecture 17: Copy of Disease Guest Lecture
10/5/17
Guest Lecturer: John ___
● Don’t know the baseline for what reefs were like/ are meant to be like
● The rate of change in coral cover in different places in different times
○ Regional average was 22% ten years ago(?), now around 13-18%
○ Phase shift- transitions of dominance- coral to macroalgae dominance
○ Do we see those changes around the world?
■ GBR, Florida Keys, Indo-Pacific, Greater Caribbean
■ Percent coral cover is low and macroalgae high in FK
■ Coral has died, but has not been replaced by macro algae in GBR
● When corals die, the reef becomes dominated by soft corals, seaweed, and sponges
(not just getting covered in macroalgae- more complex than that)
● Grime’s C-S-R Triangle theory
○ Plants can generally categorized into different functional groups
○ R-selected vs K-selected species categorized into Ruderal (increasing
disturbance, weedy), Stress-tolerant (increasing stress), and Competitive
strategies (increasing competition)
○ Traits such as growth rate, reproductive mode, how much energy it puts into
reproduction, etc map onto these strategies
○ Trade-offs- can’t be good at everything
○ www.coraltrait.net - mapping the triangle theory on corals → Emily Darling
■ Cluster of competitive corals (fast growing corals such as Acroporids- but
most disturbant-intolerant species with weak immune systems)
■ Cluster of stress-tolerant corals (brain corals, boulder corals such as
Orbicella) but hard to define stress
■ Cluster of brooding weedy corals (weedy taxa- Porites astreoides)-
weedy= get in quickly after a disturbance
● Brooding are fertilized internally and produce a lot less at a time
● Reproduce and colonize quickly, though generally lower growth
rates (not a ton of energy put into calcification)
● Much less structural complexity in reefs now
○ Less hiding places within the reef
○ Structural complexity related to diversity- fish richness tracts the loss of coral
○ Reef rugosity measurements- flattening of reefs
● Reef accretion is determined by two main things:
○ Reef accretion- measured in mm/year (how quickly is reef growing vertically)
○ Types of corals (i.e. different growth rates)
○ Overall coral cover
● Threats to reefs: what is killing the corals?
○ Ideas/possible drivers
■ Oil plantations/ agricultural sediment runoff (not really universal though)
■ Crown-of-thorns Starfish outbreaks (insufficient data)
■ Fishing/ fish traps and spearfishing (over-fishing)
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Don"t know the baseline for what reefs were like/ are meant to be like. The rate of change in coral cover in different places in different times. Oil plantations/ agricultural sediment runoff (not really universal though) Phase shift- transitions of dominance- coral to macroalgae dominance. Percent coral cover is low and macroalgae high in fk. Coral has died, but has not been replaced by macro algae in gbr. When corals die, the reef becomes dominated by soft corals, seaweed, and sponges (not just getting covered in macroalgae- more complex than that) Plants can generally categorized into different functional groups. R-selected vs k-selected species categorized into ruderal (increasing disturbance, weedy), stress-tolerant (increasing stress), and competitive strategies (increasing competition) Traits such as growth rate, reproductive mode, how much energy it puts into reproduction, etc map onto these strategies. Www. coraltrait. net - mapping the triangle theory on corals emily darling.
