BERMUDA

	BERMUDA Biodiversity of Coral Reefs
PAGE INDEX EAS class site Index: Jana Bermuda Index Question Abstract Introduction Methods Results Discussion Conclusion Literature Cited	Materials Transect Dive weight Pencil Slate Thermometer Gorgonian Key Key to Hard Corals Methods Site Selection Main Study Wells and North Site Selection Three locations were chosen for intensive study based on different physical properties: John Smith bay, Whalebone Bay, and Castle Harbor. Two more locations were studied with less accurate methods; Well’s Bay and North Rock. Well’s bay was information was collected in too short of a time scale to conduct the full methods and North Rock was too deep to run a transect. -top- Main study - Intensive site Transect Placement At each location we arrived on site and recorded location name, day, time, weather, and tide conditions. We entered the water carrying a measuring tape with the end attached to a dive weight, a pencil, a thermometer, and a slate for recording data. The area was surveyed, and a location for a transect was chosen based on habitat heterogeneity. The goal was to pick an area that was a representative sample of the whole bay (as we had explored it). Site placement was only limited by depth, it could not be too deep because the survey was done by diving and swimming along the transect, which became too difficult when deeper then about 5 meters (especially with the wave action at the shore). The dive weight was dropped at one end of the chosen transect location and the measuring tape was unraveled in a straight line. Transect lines were limited in length due to two factors, the tape had to stay straight and weighted on the floor and the unweighted end of the transect had to be snuggled under some rock/dead coral formation at the far end. As happy accident would have it, it has been shown that regional species richness is accurately calculated at transects that are as small as 10 meters long, and the minimum transect length in this study was 8 meters long (Karlson and Cornell 2000). This was the only transect below 10 meters in length and the average length was 27.4 ± 14.3 meters. Length of the transect could be variable because the data was standardized as density per meter squared during statistical analysis. Collecting Data Coral species were counted along the right side of the measuring tape in a meter wide transect. The taxa included were: Diploria strigosa, D. labyrinthiformis, Porites astreoides, Montastaea fanki. Gorgonia ventailna, Pseudopterogorgia sp, Briareum asbestinum, Plexaurella sp. Pamphlets from the BBSR was used for taxonomic identification (Bilewich 2007). Step 6 was repeated for the left side of the transect (to maximize time and transect numbers), with a slight offset from the tape so that individuals found directly under the tape were carefully omitted from this count. Special Adjustment: Castle Harbor Causeway The Castle Harbor causeway site was too shallow and too sparsely populated to conduct meaningful studies with the shorter transects. Instead, a swim by method was conducted, counting individuals in about a meter wide line of vision for a certain number of kicks. Kicks were timed three separate times along a transect (3.33 kicks constituted 1 meter). The count data was transformed to density measures in an excel spreadsheet. Data Analysis Density measures were compared between locations for each taxon recorded (excluding Pseudopterogorgia sp, Montastaea fanki, because they were not found in the where transects were placed in the three intensive study sites) using ANOVA and subsequent Tukey-Kramer tests. The ANOVA determined if there was variation in density distribution for the coral taxon between the three locations and the Tukey-Kramer test determined what locations accounted for the difference (are all three different, are two the same, which two?). For each location a Shannon evenness index (SHEI) was conducted to determine overall species richness and evenness among all taxa present. SHEI was conducted using average percent cover of all transects measured in the location. -top- Wells Bay and North Rock The same species were counted, but measured in percent cover over the entire area surveyed. The area surveyed was a subset along an imaginary transect that was about 15 meters long. The percentage was a rough estimate based on observation. The percent cover was used in a SHEI to characterize the sites, but could not be compared empirically to the density derived data due to lack of accuracy. -top-

Biodiversity of Coral Reefs

PAGE INDEX

Question

Abstract

Introduction

Methods

Results

Discussion

Conclusion

Literature Cited

Materials

Transect

Dive weight

Pencil

Slate

Thermometer

Gorgonian Key

Key to Hard Corals

Methods

Site Selection Main Study Wells and North

Site Selection

Three locations were chosen for intensive study based on different physical properties: John Smith bay, Whalebone Bay, and Castle Harbor. Two more locations were studied with less accurate methods; Well’s Bay and North Rock. Well’s bay was information was collected in too short of a time scale to conduct the full methods and North Rock was too deep to run a transect.

-top-

Main study - Intensive site

Transect Placement

At each location we arrived on site and recorded location name, day, time, weather, and tide conditions.

We entered the water carrying a measuring tape with the end attached to a dive weight, a pencil, a thermometer, and a slate for recording data.

The area was surveyed, and a location for a transect was chosen based on habitat heterogeneity. The goal was to pick an area that was a representative sample of the whole bay (as we had explored it). Site placement was only limited by depth, it could not be too deep because the survey was done by diving and swimming along the transect, which became too difficult when deeper then about 5 meters (especially with the wave action at the shore).

The dive weight was dropped at one end of the chosen transect location and the measuring tape was unraveled in a straight line. Transect lines were limited in length due to two factors, the tape had to stay straight and weighted on the floor and the unweighted end of the transect had to be snuggled under some rock/dead coral formation at the far end. As happy accident would have it, it has been shown that regional species richness is accurately calculated at transects that are as small as 10 meters long, and the minimum transect length in this study was 8 meters long (Karlson and Cornell 2000). This was the only transect below 10 meters in length and the average length was 27.4 ± 14.3 meters. Length of the transect could be variable because the data was standardized as density per meter squared during statistical analysis.

Collecting Data

Coral species were counted along the right side of the measuring tape in a meter wide transect. The taxa included were: Diploria strigosa, D. labyrinthiformis, Porites astreoides, Montastaea fanki. Gorgonia ventailna, Pseudopterogorgia sp, Briareum asbestinum, Plexaurella sp. Pamphlets from the BBSR was used for taxonomic identification (Bilewich 2007).

Step 6 was repeated for the left side of the transect (to maximize time and transect numbers), with a slight offset from the tape so that individuals found directly under the tape were carefully omitted from this count.

Special Adjustment: Castle Harbor Causeway

The Castle Harbor causeway site was too shallow and too sparsely populated to conduct meaningful studies with the shorter transects. Instead, a swim by method was conducted, counting individuals in about a meter wide line of vision for a certain number of kicks. Kicks were timed three separate times along a transect (3.33 kicks constituted 1 meter).

The count data was transformed to density measures in an excel spreadsheet.

Data Analysis

Density measures were compared between locations for each taxon recorded (excluding Pseudopterogorgia sp, Montastaea fanki, because they were not found in the where transects were placed in the three intensive study sites) using ANOVA and subsequent Tukey-Kramer tests. The ANOVA determined if there was variation in density distribution for the coral taxon between the three locations and the Tukey-Kramer test determined what locations accounted for the difference (are all three different, are two the same, which two?).

For each location a Shannon evenness index (SHEI) was conducted to determine overall species richness and evenness among all taxa present. SHEI was conducted using average percent cover of all transects measured in the location.

-top-

Wells Bay and North Rock

The same species were counted, but measured in percent cover over the entire area surveyed. The area surveyed was a subset along an imaginary transect that was about 15 meters long. The percentage was a rough estimate based on observation.

The percent cover was used in a SHEI to characterize the sites, but could not be compared empirically to the density derived data due to lack of accuracy.

-top-