1. Hilary Hamilton, Samantha Scriber, Isla Murphy, Jenna Munden, Katherine Fraser, Joe McSheffery
Interactions between Individual Substrate Type and Macrofauna Biodiversity in the Midlittoral Rocky Intertidal

2. Overview Introduction Research Questions and Hypotheses
Materials and Methods
Results and Discussion
Conclusions

3. Introduction

4. Background Information
Sediment characteristics reflect the salinity, oxygen content, pore-water content, temperature, food availability, sedimentation rate, substrate consistency, turbidity, and predation found in a particular environment
sediment characteristics define what organisms can survive in the environment
Biodiversity: describes the sum total variation of life forms in a specific environment.

5. Previous Studies
community structure varies with the type, complexity and heterogeneity of the substrate (Holland & Elmore, 2008).
Previous studies have reported that substrate heterogeneity enhances the diversity of macrobenthos species (Wang et al, 2009).
preferable environment for settling, breeding, and preying, as well as better shelter, and richer food sources in comparison to other habitats

6. Rocky Intertidal Zone
Interface between marine and terrestrial habitats
Substrates typically found in the rocky intertidal zone include bedrock, boulder, cobble, gravel, sand and algae
The mixture of substrates changes based on tidal location and other environmental factors such as wave exposure at a particular location.

7. Gap in Knowledge
Details relating to substrate types are often overlooked leading to an oversimplified experimental design
Time consuming
Complex intertidal conditions

8. Research Questions
Goals - in depth analysis of substrate composition and biodiversity
Among heterogeneous substrates, which types of substrate promote the highest level of biodiversity in the rocky shore intertidal zone located off of the Passamaquoddy Bay?

9. Hypothesis Biodiversity will be highest at sites with algal cover.
provides a buffer of external stressors such as heat, desiccation, and wave stress for invertebrates
in high densities algae may trap sediment and smother the invertebrates or limit feeding but this effect will be reduced by the high wave action characteristic of the rocky intertidal zone.

10. Materials and Methods

11. Materials 1 m2 quadrat 100m Transect
Plastic bags to transport specimens
Aquarium to store specimens at Hunts
Species Identification guide

12. Methods
Sampled at Indian Point, Bar Road, Left and Right of Road at Green’s Point
Mid-intertidal zone Parallel with shore. Limiting factors between quadrats.

13. Methods Sampled 10m intervals.
Each quadrat recorded substrate coverage

14. Substrates Sand/Mud/Silt= Any sediment smaller than a fingernail
Algae= Ascophyllum nodosum, Vertebrata lanosa, Fucus vesiculosus
Cobble= Stones smaller than your fist, larger than fingernail
< x <
Rock= Larger than your fist, large enough to move easily
Bedrock

15. Methods Members of group counted organisms and they were recorded
Identified in the field
Given identifying characteristic and brought back to Huntsman Marine Center
Identified at Huntsman Marine Center using identification key, dissecting scope.
Recorded in excel

16. Results and Discussion

17. Diversity Indices Weighted towards evenness
Shannon-Wiener
Simpson’s
Weighted towards evenness
Measures representation of a species throughout a sample
Diversity at a minimum at 0
Weighted towards abundance
Measures the probability of two organisms being the same species
Diversity at a maximum at 0
Both the Shannon-Wiener Index and the Simpson’s Diversity Index are ways to measure a habitat’s diversity with regard to the evenness of species and the abundance of species. However, Simpson’s Diversity is weighted more towards the abundance of species while the Shannon-Wiener Index is weighted more towards the evenness of species. Simpson’s Diversity Index measures the probability that two individuals randomly selected from a population will be the same species. The Shannon-Wiener Index measures whether species are well represented throughout the entire sample. We used both measures of diversity for an extra measure of diversity. One’s not better than the other

18. Hard-Substrates: Cobble
Shannon-Wiener
Simpson’s
These graphs are an example of the primary method of data manipulation used in our experiment. For all substrate types Shannon-Wiener Index and Simpson’s Diversity were plotted against the percentage of substrate covering a quadrat, in this case it was cobble. Both graphs show a general increase in diversity as the percentage of cobble cover increases and p-values were calculated from a linear regression analysis to tell us whether the slopes of the line were significantly different than 0.
P=0.6545
P=0.2206

19. Significance
To determine whether trendlines fit the data for the graphs comparing substrate cover and species diversity, a linear regression test was performed. Other that Shannon-Wiener Index data for bedrock cover, no substrates had a significant trend with increasing or decreasing diversity.
Significance of trendline determined by linear regression analysis

20. Bedrock Significance
Significant p-value of for linear analysis with Shannon’s diversity
Increasing bedrock cover relates to decreasing biodiversity
Significant cover range 10% to 100%
Intermediate Disturbance Hypothesis

21. Habitat Complexity and Biodiversity
To look at how the complexity of a habitat affects diversity, diversity was plotted against the number of substrates observed in each quadrat. This was done with each sampling site and repeated with each measure of diversity

22. Wikstrom & Kautsky (2007)
Increased biomass of understory organisms in areas with Fucus compared to areas without Fucus.
Since no species were specific to Fucus, this result can be assumed to be due to the characteristic of Fucus being an ecosystem engineer.
Habitat amelioration-shading properties, thermal and dessication stress buffering abilities.

23. Chi2 Test for Biomass Bar Road Indian Point Green’s Point: Right
Green’s Point: Left
To determine whether substrate has an affect on biomass, a t-test was performed. This was done by comparing the number of species found in each quadrat to the expected values if all were distributed evenly. All sampling sites were determined to have a non random distribution over the transect.

24. Soft Substrates: Algae
Biomass
Each transect showed significant difference in the number of animals in each plot than what would be expected by chance.
Sampling Site
3 plots with highest algal coverage
Observed % of biomass
Expected % of biomass
Green’s Point
Left 68 30
Right 82 50
Indian Point
Bar Road 48
Shows effect of substrate? Environment? Could be many factors but will concentrate on substrate.
Using plots with the highest % of algal coverage. At green’s point left there was 5 with 100% algal coverage so they all were used.
Chi SqUaReD!!!

25. Species Distribution Indian Point
Another way we manipulated the data was by looking at the number of each species found at each sampling site. In the red boxes, you can see the number of barnacles found at Indian Point

26. Species Distribution
Bar Road
And again at bar road

27. Species Distribution Green’s Point: Left
But something that we found interesting is that on either side of bar road, there were little

28. Species Distribution Green’s Point: Right No Barnacles
Or no barnacles found

29. Jenkins, Norton & Hawkins, 1999
Negative interaction between algae and cyprid.
Positive interaction between algae and adult.
In general
Negative interaction: macro algae interacts negatively by reducing access to the substratum, due to reduced flow under the canopy. The sweeping motion of the fronds during submersion enhances this negative effect and functions to destroy or sweep away cyprids.
Positive interaction: buffering capacity, thermal and water stress
Varying results with specific algae species as well as exposure of the shore

30. Soft Substrates: Algae
Algae and Barnacle interactions
Sampling Site
Number of Barnacles
% of total Algae coverage
Green’s Point
Left 87
Right 11
63.5
Indian Point
1294
1.3
Bar Road
811
2.53
Clearly there is a relationship between barnacles the substrate algae…algae is appearing to inhibit barnacles.

31. Soft Substrates: Algae
Vertebrata lanosa and Ascophyllum nodosum
Hemiparastic, A plant, such as mistletoe, that obtains some nourishment from its host but also photosynthesizes
Polysiphonia attaches to the receptacles, air bladders and damaged blades of Ascophyllum
This is accomplished by the extensive network of Polysiphonia’s rhizoids (Ciciotte & Thomas, 1997). Polysiphonia lanosa and its host exchange photoassimilates, energy storing compounds created by photosynthesis (Ciciotte & Thomas, 1997).
Vertebrata lanosa not acting as a shading algae.
In our research, polysiphoina was only found with ascophyllum
Polysiphonia does not affect diversity of the ascophyllum environment

32. Conclusions
Although we observed some interactions between substrates and biodiversity
Significant findings:
Bedrock = significant negative interaction
Chi-squared test for heterogeneity of substrate and biomass
Simplistic substrate definitions
Greater sample sizes could lead to more concrete conclusions

33. Questions?