The effect of plant coverage on macro-invertebrate density and diversity in the intertidal zone
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Transcript of The effect of plant coverage on macro-invertebrate density and diversity in the intertidal zone
The effect of plant coverage on macro-invertebrate density and diversity in the intertidal
zone
Sarah Park, Bailey Shuttleworth Cucinelli,
James Holobow, and Jenna Shaw
Introduction● Ecologically important region
● Few studies on the effects of flora on faunal biodiversity
● Goal: provide greater understanding of marine interactions
Indian Point
Green’s Point
Bar Road
Ascophyllum nodosum
Fucus vesiculosus
Polysiphonia lanosa
Fauna
Littorina obtusataLittorina littorea Thais lapillus
FaunaBalanus balanoides Gammarus oceanicus
Invertebrate Density
● L. obtusata and G. oceanicus live in patches of seaweed
● L. littorea feed on algae
● B. balanoides and T. lapillus seek shelter from wave action
● Large and aggregated vegetation shelter greater number of invertebrates
Hypothesis 1:
● Amount of plant cover on intertidal regions of the Bay of Fundy is positively correlated with invertebrate density.
Invertebrate Biodiversity
● High biodiversity → stable and productive communities
● Schooner (1974): niche diversification/complex habitats may increase species richness○ quantify habitat complexity?
● Gunnill (1982): artificial increase and diversity may decrease with increased plant cover
Hypothesis 2:
● Amount of plant cover on intertidal regions of the Bay of Fundy is negatively correlated with invertebrate biodiversity.
Materials● line transect● 1 m quadrat● 25 cm quadrat● plastic collection bags for
samples
● ten sites over 100 m● constant altitude● surface species were
collected ● identified in the lab
Methods
Results
Discussion Indian Point
● Lowest plant cover (3.9 samples/m2)● Second largest fauna density (173.1
samples/m2)● Second highest diversity
(H’=0.307)Hypothesis 1: Not AcceptedHypothesis 2: Accepted
Discussion Green’s Point
● Largest plant cover (42.8 samples/m2)● Lowest fauna density (97.2 samples/m2)● Greatest diversity (H’=0.683)
Hypothesis 1: Not AcceptedHypothesis 2: Not Accepted
Discussion Bar Road
● Second Highest plant cover (7.2 samples/m2)
● Largest fauna density (275.8 samples/m2)● Lowest diversity (H’=0.088)Hypothesis 1: AcceptedHypothesis 2: Accepted
Sources of Error
• hard to distinguish holdfasts in high density of plants
• distance from the water’s edge was not measured
• inconsistent tide phase• time restriction
Conclusion
- Our study did not produce concrete results - Overall data is inconsistent- Multiple factors (abiotic/biotic) influence invertebrate density/diversity.