Dataset: Percent cover of Millepora at Cabritte Horn

Name: Abundance and percent cover of Millepora species at Cabritte Horn (St.John, US Virgin Islands) from 1992-2021
Published: 2022-06-09
Keywords: Millepora species, coral cover, reef, Caribbean, biota, oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.875524.1

Spatial Extent: N:18.3075 E:-64.7219 S:18.3075 W:-64.7219

Temporal Extent: 1992-05-30 - 2021-07-23

Project:

RUI: Pattern and process in four decades of change on Caribbean reefs (St John Coral Reefs)

Principal Investigator:

Peter J. Edmunds (California State University Northridge, CSUN)

BCO-DMO Data Manager:

Dana Stuart Gerlach (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2022-06-09

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Abundance and percent cover of Millepora species at Cabritte Horn (St.John, US Virgin Islands) from 1992-2021

Abstract:

These data describe the abundance of Millepora species (as percent cover) at Cabritte Horn, St. John, US Virgin Islands from 1992-2021. They are used to evaluate how the abundance of this coral (% cover) has changed over three decades.

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Archival Copy

Version Date	Archive	Persistent Identifier	Date Assigned
2022-06-09	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.875524.1	2022-06-16

Methods & Sampling

Abundance of Millepora species was examined by measuring percent cover at Cabritte Horn in St. John, US Virgin Islands across three decades. Photographic sampling of quadrats (0.5m x 0.5 m) was performed from 1992 to 2021 using cameras mounted on a framer about 80 centimeters above the reef. Color slide film was used from 1992–2000 (and digitized at 4000 dpi), with digital photography implemented in 2001. Photoquadrats were recorded at random positions along the transect, which was 20 meters long from 1992–1999 and 40 meters long from 2000-2021.

The abundance of Millepora sp. chaotically changed from 1992 to 2021 in concert with hurricanes, bleaching, and macroalgal crowding. To access images showing these patterns, see Related Publications section below for Coral Image Downloads and Viewer link (Cabritte Horn images can be found under "Random Sites"). For details on percent cover of macroalgae, see dataset https://www.bco-dmo.org/dataset/875543 (see Related Datasets section below).

Data Processing Description

Photoquadrats were used to quantify Millepora abundance using ImageJ software (Abràmoff et al., 2004). Areas of encrusting Millepora sp. were located in each photoquadrat, outlined, and their areas measured with all pieces of sheet forms quantified separately. Because Millepora species’ sheet forms meander across the substratum and are prone to fission, it was not always clear where colonies began and ended within photoquadrats. Colonies therefore were defined as areas of autonomous tissue, so portions of colonies that were partially within the photoquadrats (uncommon) were scored as separate colonies. The area of sheets were summed by quadrat and used to calculate the percentage cover of Millepora sp.

Statistical analyses
The morphology of Millepora sp. (log transformed), macroalgal cover (arcsine transformed), and temperature were compared among years using one way ANOVAs with Bonferonni post hoc analyses to compare between years (using Systat 13 software). The capacity of Millepora sp. to exploit a sheet-tree morphology was quantified (see 'Millepora features' dataset: https://www.bco-dmo.org/dataset/875553)

BCO-DMO processing
- converted Date to YMD format
- added columns for latitude and longitude
- added columns for location and camera type
- added conventional header with dataset name, PI name, version date
- modified parameter names to conform with BCO-DMO naming conventions

Data Files

File
millepora_cover.csv (Comma Separated Values (.csv), 105.35 KB) MD5:4b3f95fbfede1f11e4b107839fa036a9 Primary data file for dataset ID 875524

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-2019992

Deployments

None available yet

Instruments

Camera

Supplied Name: Nikonos V film camera

Supplied Description:

A Nikonos V film camera with 28 mm lens was used in the years 1992-2000

Instrument Type

Generic Name: Camera

Acronym: camera

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/311/

Generic Description:

All types of photographic equipment including stills, video, film and digital systems.

Camera

Supplied Name: Nikon Coolpix 990

Supplied Description:

A Nikon Coolpix 990 digital camera with 8-24 mm lens was used in the years 2001-2005

Instrument Type

Generic Name: Camera

Acronym: camera

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/311/

Generic Description:

All types of photographic equipment including stills, video, film and digital systems.

Camera

Supplied Name: Nikon DSLR digital camera

Supplied Description:

A Nikon DSLR D70/DX digital camera with 18-70 mm lens was used in the years 2006-2010
A Nikon DSLR D90/DX digital camera with 18-70 mm lens was used in the year 2011
A Nikon DSLR D7000/DX digital camera with 18-70 mm lens was used in the years 2012-2015
A Nikon DSLR D810/FX digital camera with 18-35 mm lens was used in the years 2016-2021

Instrument Type

Generic Name: Camera

Acronym: camera

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/311/

Generic Description:

All types of photographic equipment including stills, video, film and digital systems.

Parameters

Date and time formats are described in python strftime() syntax.

Supplied Name	Supplied description	Supplied Units	Standard Name
Latitude	Latitude	decimal degrees	lat
Longitude	Longitude	decimal degrees	lon
Sampling_Date	Date of photographic quadrat sampling Format: %Y-%m-%d	unitless	date
Quadrat_number	Quadrat number	unitless	sample
Percent_cover_Millepora	Percentage cover of Millepora species	percent (%)	percent_cover
Location	Geographical location	unitless	region
Camera	Type of camera and lens used for photographic quadrat sampling	unitless	inst_model

Database

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Dataset: Percent cover of Millepora at Cabritte Horn