Download Do the physical dimensions of a tide pool affect the diversity of

Effects of tide pool volume
on pool diversity
Lindsay Grant, Anna Mairs, Charlotte Martin, Natalie Rideout and Gillian
Tetlow
The Rocky Intertidal – Tide Pools
• The coastal area that is exposed
during low tide and submerged during
high tide
• Contains a high biodiversity of species
• A receding tide leaves an
accumulation of pools
Tide pools
• Allow organisms to escape high temperatures and desiccation
• Acts as breeding and nursing grounds, provides protection and a
feeding habitat
• Can also be stressful environments
• Changing ocean salinity, temperature and pH
Goal of Study
• To determine if the tide pool size affects the species diversity
• Hypothesis
- Species abundance will increase with increased size and depth
of tide pools
- However, species distribution will not be significantly different
between varying tide pool dimensions
Methods
• Sampled 10 random tide pools of
different sizes
• Measured dimensions
• Used a quadrat (1m x 1m) for larger
pools
• Collected samples of all plants and
animals present
• Plant coverage estimated
• Identified all species in the lab
http://vitalsignsme.org/sites/default/files/climatechange12012/0
49.jpg
Methods – Calculations
• Simpson’s Diversity Index:
𝐷 =1−
Σ 𝑛(𝑛−1)
𝑁(𝑁−1)
n = total number of organisms of a particular species
N = total number of organisms of all species
Methods – Calculations
• Shannon-Wiener Diversity Index:
𝐻 = −𝛴 𝑝𝑖 ln 𝑝𝑖
pi = proportion of total sample represented by species i
• H’max:
𝐻′𝑚𝑎𝑥 = ln 𝑆
S = number of species
Results
• Plant average – 4.3
• 12 species total
• Animal average – 4.9
• 18 species total
Results
Results
Results
• No significant patterns found for plant or animal diversity
• More sparse species of animals found than plants
Discussion
Plants:
• 3 outliers
• Constant diversity irrespective of
tide pool size
• Failed to support hypothesis
http://www.clarku.edu/departments/biology/biol201/2002/EMachala/Galler
y.htm
Discussion
Animals:
• Similar to plants, 2 outliers
• Richness vs Abundance
• Failed to support hypothesis
https://www.clarku.edu/departments/biology/biol201/2002/JDubois/Marine%20
Gastropods.htm
Discussion
Confounding variables:
• Ambient conditions
• Elevation
• Uneven distribution of pool volumes
http://www.acurite.com/7-5-thermometer-00338.html
Discussion
Supporting studies:
• Cullity (2012)
• Found no significant relationship
Biological relevance:
• Metaxas and Scheibling (1993)
• Refuge area from stressful conditions
Questions?