Data covering the marine environment, including fisheries, coral reef  health, ocean chemistry, and coastal zones.

oceans-seas-coasts

Oceans, Seas, & Coasts

### Overview  
  
This dataset estimates the level of connectivity between each area containing coral reefs and other such areas. Connectivity refers to the extent to which populations are linked by the exchange of eggs, larval recruits, juveniles, or adults—an exchange which is primarily conducted via ocean currents. A coral larvae dispersal probability model developed by Wood et al. was applied by the 50 Reefs Project to simulate coral exchange between 2003 and 2011, ultimately yielding connectivity estimates globally at 0.05° resolution. These estimates were based on potential dispersal only; settlement and post-settlement survival were not modelled.

  
  
Connectivity within and between protected areas is important for maintaining diversity, fish stocks, and especially important for maintaining ecological resilience. While poorly understood, it is a key factor to consider in marine reserve design as it may enhance resilience to disturbance and be important for the persistence of populations. Both of these are important processes in the context of conservation planning under climate change, the dominant threat to coral reefs in the coming decades. Even if the goals of the Paris Climate Agreement are achieved, 70-90% of coral reef areas are likely to cease to be suitable for coral growth by mid-century. Coral communities that survive will play a key role in the regeneration of reefs by mid-to-late century. 

  
  
The purpose of the 50 Reefs Project was to develop a long-term strategic plan for the conservation of coral reefs by identifying 50 large (500 km²) regions that are the least vulnerable to climate change and which are positioned to facilitate natural coral reef regeneration. These locations constitute important opportunities for novel conservation investments to secure less vulnerable yet well-connected coral reefs that may help to repopulate degraded areas after the climate has stabilized. The strategy and actions proposed by the project should strengthen and expand existing conservation efforts for coral reefs as the world faces the long-term consequences of intensifying climate change.  
  
### Methodology  
  
The authors used a coral larvae dispersal probability model developed by [Wood et al.](https://doi.org/10.1111/geb.12101), basing their findings on simulations of larvae dispersal over a 93 month period. Within this modeling, 115 million particles (representing larvae from a generic broadcast spawning coral) were released from each of 12,397 habitat cells on a monthly basis between 2003-2011. Again following Wood et al., the authors used two measures of connectivity: (i) outgoing settlement, which is the proportion of particles that reached any habitat cell, including the source cell, and (ii) export, which is the proportion of particles reaching any cell other than the source cell, hence omitting self-seeding. These were combined into an overall "connectivity" score.

  
  
The dataset contains entries for each of the approximately 54,586 0.05° degree (approximately 25 km² but [changes with distance from the equator](https://www.thoughtco.com/degree-of-latitude-and-longitude-distance-4070616)) raster cells identified as containing coral habitat by a dataset from [Coral Reef Watch](https://coralreefwatch.noaa.gov/). The values were standardized to mean 0 unit variance for subsequent analysis by subtracting the mean and dividing by the standard deviation. The resulting scores reflect how far the values were below or above the population mean. The data table also contains: (1) an ID field that assigns a unique numeric identification number to each cell; (2) two fields representing the latitude and longitude of the center of the cell; (3) scores corresponding to other essential components of the 50 Reefs assessment; and (4) one final variable representing the aggregate score of the 50 Reefs analysis.

  
  
For the full documentation, please see the source [methodology](https://conbio.onlinelibrary.wiley.com/doi/full/10.1111/conl.12587).
  
  
### Additional Information  
  
Resource Watch shows only a subset of the dataset. The 50 Reefs initiative generated scores for several other factors crucial to their assessment: thermal history and recent thermal conditions, predicted future thermal conditions, and cyclone and storm risk. In total, the component scores were derived from 174 separate variables relevant to these topics; these components were also combined into one final assessment score using a custom weighting.

  
  
For access to the full dataset and additional information, click on the “Learn more” button.
  
  
### Visualizing the Data  
  
Our team reformatted this dataset before displaying it on Resource Watch. See the documentation on how Resource Watch processed the data on [Github](https://github.com/resource-watch/data-pre-processing/tree/master/ocn_017_coral_reef_connectivity).  
  
### Disclaimer  
  
Excerpts of this description page were taken from the source metadata.

University of Queensland (U of Queensland)

50 Reefs Global Coral Ocean Warming, Connectivity and Cyclone Dataset

ocn-017-coral-reef-connectivity-rw

ocean-watch

Ocean Watch

2011 Coral Reef Connectivity

Extent to which populations are linked by the exchange of eggs, larval recruits, juveniles or adults, as well as the extent of ecological linkages with adjacent and distant habitats