Data Access Form

Dataset Title:	[Rare corals in the Caribbean: Small coral density from quadrats] - Density of small corals from quadrats on shallow reefs of St. John, USVI, 1994-2024 (RUI: Pattern and process in five decades of change on Caribbean reefs)
Institution:	BCO-DMO (Dataset ID: bcodmo_dataset_1010997_v1)
Information:	Summary \| License \| Metadata \| Background \| Files \| Make a graph

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Variable	Minimum	Maximum
Site (unitless)	"Cabritte"	"Yawzi"
Year (Year)	1994	2024
Quadrat (Number)	1	40
Diploria (Number)	0	4
Porites (Number)	0	17

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The Dataset Attribute Structure (.das) for this Dataset

Attributes {
 s {
  Site {
    String long_name "Site";
    String units "unitless";
  }
  Year {
    Int32 actual_range 1994, 2024;
    String long_name "Year";
    String units "Year";
  }
  Quadrat {
    Int32 actual_range 1, 40;
    String long_name "Quadrat";
    String units "Number";
  }
  Diploria {
    Int32 actual_range 0, 4;
    String long_name "Diploria";
    String units "Number";
  }
  Porites {
    Int32 actual_range 0, 17;
    String long_name "Porites";
    String units "Number";
  }
 }
  NC_GLOBAL {
    String cdm_data_type "Other";
    String Conventions "COARDS, CF-1.6, ACDD-1.3";
    String creator_email "info@bco-dmo.org";
    String creator_name "BCO-DMO";
    String creator_url "https://www.bco-dmo.org/";
    String doi "10.26008/1912/bco-dmo.1010997.1";
    String history 
"2026-11-14T16:41:30Z (local files)
2026-11-14T16:41:30Z https://erddap.bco-dmo.org/erddap/tabledap/bcodmo_dataset_1010997_v1.html";
    String infoUrl "https://osprey.bco-dmo.org/dataset/1010997";
    String institution "BCO-DMO";
    String license 
"The data may be used and redistributed for free but is not intended
for legal use, since it may contain inaccuracies. Neither the data
Contributor, ERD, NOAA, nor the United States Government, nor any
of their employees or contractors, makes any warranty, express or
implied, including warranties of merchantability and fitness for a
particular purpose, or assumes any legal liability for the accuracy,
completeness, or usefulness, of this information.";
    String sourceUrl "(local files)";
    String summary 
"Density of small (≤4 cm) brain coral (Diploria and Pseudodiploria) and Porites colonies from quadrats on shallow reefs of St. John, US Virgin Islands, 1994-2024. This dataset supports the results of the publication \"Encroaching rarity of Caribbean reef corals\" (Edmunds et al., 2026) and is part of the study described below.

Study description: 
Declining coral cover is causing coral colonies to occur farther apart and at lower densities, thus challenging their persistence. Here we test for population declines of Caribbean brain (Diploria labyrinthiformis, Pseudodiploria strigosa, and P. clivosa) and pillar (Dendrogyra cylindrus) corals on the reefs of St. John, US Virgin Islands, and use hectare-scale sampling with geolocation of corals to evaluate the implications of low densities. Sampling over four decades using photoquadrats demonstrated declines in population size, but surveys of 4.63 hectares of reef in 2024 revealed lower density estimates, even though 1,323 colonies were found. Many colonies occurred closer together than chance alone would predict, with mean nearest neighbor distances of 0.8–11.4 m for brain corals and ~74 m for pillar coral. Brain corals also formed clusters in high-density hot spots. Nonetheless, ≤7% of brain corals were close enough together to support 30% fertilization, and 33% of brain colonies were far enough apart that fertilization was 0%. Populations of these species in St. John may be facing further population declines through Allee effects, with the risk acute for Dendrogyra. These results underscore the need to augment monitoring of coral reefs with spatially explicit sampling of corals on a hectare scale.

See the Related Datasets section for other datasets from this study.";
    String title "[Rare corals in the Caribbean: Small coral density from quadrats] - Density of small corals from quadrats on shallow reefs of St. John, USVI, 1994-2024 (RUI: Pattern and process in five decades of change on Caribbean reefs)";
  }
}

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