The Effects of Substrate Composition on Intertidal Organism Diversity

The Effects of Substrate Composition on Intertidal

Organism Diversity Hala Nader, Alyson Pickard, Sam Shaw, & Jenna Thebeau

Diversity◦ Probability that two randomly selected organisms

from a community will belong to a different species

Background - Terms

Diversity◦ Probability that two randomly selected organisms

from a community will belong to a different species

Richness◦ Number of species in a community

Background - Terms

Diversity◦ Probability that two randomly selected organisms

from a community will belong to a different species

Richness◦ Number of species in a community

Evenness◦ The degree of similarity in the distribution of each

species within the community

Background - Terms

What effects diversity?◦ Vertical & horizontal stress gradients◦ Wave exposure◦ Temperature◦ Desiccation◦ Shelter availability

Introduction

Limitation Stress◦ Lack of available resources

Types of Stress

Limitation Stress◦ Lack of available resources

Disruptive Stress◦ Causes cellular damage

Types of Stress

3 categories:◦ Supralittoral◦ Midlittoral ◦ Infralittoral

Vertical Stress Gradients

3 categories:◦ Supralittoral◦ Midlittoral ◦ Infralittoral

Depends on elevationand exposure

Vertical Stress Gradients

Depend on ice scour intensity and wave exposure

Horizontal Stress Gradients

Depend on ice scour intensity and wave exposure

Wave exposure determines what type of substrate is found along horizontal gradient

Horizontal Stress Gradients

High wave exposure◦ Washes away small debris◦ Leaves large rocks & cobble◦ Low predation

Wave Exposure & Substrate

High wave exposure◦ Washes away small debris◦ Leaves large rocks & cobble◦ Low predation

Moderate wave exposure◦ Bedrock & cobble◦ Stable habitat

Wave Exposure & Substrate

High wave exposure◦ Washes away small debris◦ Leaves large rocks & cobble◦ Low predation

Moderate wave exposure◦ Bedrock & cobble◦ Stable habitat

Low wave exposure◦ Primarily muddy◦ Low drainage leading to anoxia

Wave Exposure & Substrate

Effect of substrate type on organism diversity and individual species preference

Aim of The Study

Effect of substrate type on organism diversity and individual species preference

Hypothesis◦ Diversity will change with respect to

substrate type

Aim of The Study

3 sites were sampled◦ Green’s Point

High wave exposure, large rock & cobble

Methods

3 sites were sampled◦ Green’s Point

High wave exposure, large rock & cobble

◦ Indian Point Moderate wave exposure, bedrock & cobble

Methods

3 sites were sampled◦ Green’s Point

High wave exposure, large rock & cobble

◦ Indian Point Moderate wave exposure, bedrock & cobble

◦ Bar Road Low wave exposure, mud & sand

Methods

10 samples along a 50 m transect line within midlittoral zone at each site

Methods

10 samples along a 50 m transect line within midlittoral zone at each site

1x1 m quadrat placed every 5 m

Methods

10 samples along a 50 m transect line within midlittoral zone at each site

1x1 m quadrat placed every 5 m

Estimation of the number of plant and animal species encountered

Methods

10 samples along a 50 m transect line within midlittoral zone at each site

1x1 m quadrat placed every 5 m

Estimation of the number of plant and animal species encountered

Species identified

Methods

Results

Plant Species Animal Species

A. nodosum C. crispus Corraline sp. Dictyosiphon sp. Elachista flaccida F. vesiculosus Lithothamnion sp. U. lactuca

Acmae testudinaris Asterias forbesii B. balanus L. littorea L. obtusata N. lapillus S. balanoides S. droebachiensis

Results

Figure 1: The diversity of the 3 substrates based on the Shannon-Wiener diversity index

Bedrock Rocky Muddy0

0.1

0.2

0.3

0.4

0.5

0.6

Substrate Type

Div

ersi

ty In

dex

Valu

e

Results

Figure 2: Species Richness and the 3 locations

Bedrock Rocky Muddy0

2

4

6

8

10

12

Substrate Type

Num

ber

of E

ncou

nter

ed S

peci

es

Results

Plant Species Animal Species

A. nodosum C. crispus Corraline sp. Dictyosiphon sp. Elachista flaccida F. vesiculosus Lithothamnion sp. U. lactuca

Acmae testudinaris Asterias forbesii B. balanus L. littorea L. obtusata N. lapillus S. balanoides S. droebachiensis

Results

Plant Species Animal Species

A. nodosum C. crispus Corraline sp. Dictyosiphon sp. Elachista flaccida F. vesiculosus Lithothamnion sp. U. lactuca

Acmae testudinaris Asterias forbesii B. balanus L. littorea L. obtusata N. lapillus S. balanoides S. droebachiensis

Results

Figure 3: Percent coverage per m2 (mean ±SEM) for 3 different substrates

A. nodosum B. balanus E. flaccida Lithothamnion spp.

S. balanoides Corraline spp. 0%

10%

20%

30%

40%

50%

60%

70%

Bedrock Rocky

Muddy

Species Name

% C

over

age

/m2

Results

Figure 4: Number of Nucella lapillus found per m2 (mean±SEM)

N. lapillus0

0.5

1

1.5

2

2.5

3

3.5

BedrockRockyMuddy

Species Name

Num

ber

of O

rgan

ism

s pe

r m

2

Results

L. littorea0

10

20

30

40

50

60 BedrockRockyMuddy

Species

Num

ber

of O

rgan

ism

s pe

r m

2

Figure 5: Number of Littorina littorea (mean ±SEM)

Results

F. vesiculosus 02468

1012141618

Bedrock Rocky

Muddy

Species

Num

ber

of O

rgan

ism

s pe

r m

2

Figure 6: Number of Fucus vesiculosus (mean±SEM)

Rocky substrate – Greens Point

◦ Ascophyllum nodosum (common brown algae) Found it in exposed areas Could be due to ability to attach to substrate

Discussion

Rocky substrate – Greens Point

◦ Ascophyllum nodosum (common brown algae) Found it in exposed areas Could be due to ability to attach to substrate

◦ Coralline spp. (red algae) and Elachista flaccide (brown algae) Sheltered due to canopy

Discussion

Rocky substrate – Greens Point

◦ Ascophyllum nodosum (common brown algae) Found it in exposed areas Could be due to ability to attach to substrate

◦ Coralline spp. (red algae) and Elachista flaccide (brown algae) Sheltered due to canopy

◦Nucella lapillus (whelk) Found due to coverage of plants

Discussion

Bedrock substrate – Indian Point

◦ Fucus vesiculosus (bladder wrack) Only grow if fucus spiralis is removed

Discussion

Bedrock substrate – Indian Point

◦ Fucus vesiculosus (bladder wrack) Only grow if fucus spiralis is removed

◦ Lithothamnion spp. (calcareous algae) Fucus could have provided shelter Rock provides suitable place to grow Larvae can settle due lower wave exposure

Discussion

Bedrock substrate – Indian Point

◦ Littorina littorea (periwinkle) Fucus provided shelter from wave exposure and

protection from desiccation Feed on green & brown algae

Discussion

Bedrock substrate – Indian Point

◦ Littorina littorea (periwinkle) Fucus provided shelter from wave exposure and

protection from desiccation Feed on green & brown algae

◦ Semibalanus balanoides (barnacle) Fucus provided shelter from wave exposure and

protection from desiccation Predators and competitors were absent from this

sampling site

Discussion

Muddy Substrate – Bar Road◦ Semibalanus balanoides (barnacle)

◦ Littorina littorea (periwinkle)

◦ Acmaea testudinalis (limpet)

Discussion

Muddy Substrate – Bar Road◦ Semibalanus balanoides (barnacle)

◦ Littorina littorea (periwinkle)

◦ Acmaea testudinalis (limpet)

◦ Possibility of burrowed organisms

Discussion

Species are not evenly distributed in environments ◦ Acorn barnacles are the dominant species◦ Plant species provide protection for animal species

Conclusions

Species are not evenly distributed in environments ◦ Acorn barnacles are the dominant species◦ Plant species provide protection for animal species

Bedrock substrates have the highest species richness

Conclusions

Species are not evenly distributed in environments ◦ Acorn barnacles are the dominant species◦ Plant species provide protection for animal species

Bedrock substrates have the highest species richness

Muddy substrates have the lowest species richness

Conclusions

Estimation of species numbers rather than an actual count of the species.

Limitations

Estimation of species numbers rather than an actual count of the species.

Sample Size

Limitations

Estimation of species numbers rather than an actual count of the species.

Sample Size

Some species not seen but present

Limitations

Greater variety of substrates

Future Direction

Greater variety of substrates

Monitoring physical and biological factors

Future Direction

Thanks!Questions?