Caribbean Shallow Hardbottom & Coral (Southeast Blueprint Indicator)

Reason for Selection Coral reefs and hardbottom serve as important habitat for much of the marine biodiversity in the Caribbean. They also provide important economic and cultural goods and services that benefit nearby coastal communities, such as supporting fisheries, filtering seawater, and buffering the impacts of storms (NOAA 2020). In addition, coral reefs can serve as environmental indicators of water quality because of their narrow temperature, salinity, and water clarity requirements (EPA 2005). While climate change will affect all habitats in the Caribbean, coral reefs are likely to face the largest impacts. According to The Nature Conservancy, “...in recent decades, coral cover throughout the region has declined by almost 60 percent. Remaining reefs are threatened by warmer waters, harsher storms, disease, overfishing and pollution” (2019). In this indicator, we score hardbottom with sparse algae higher than hardbottom with dense algae because algae negatively impact coral colonization and resilience. According to Bonaldo et al., “macroalgae can suppress the settlement, growth and survivorship of corals, thereby limiting the capacity of coral populations to recover following disturbances” (2017). Input Data * The Nature Conservancy’s (TNC) [Caribbean benthic habitat maps], accessed 12-21-2022; [read a press release about the data]; [read a scientific journal article about the data]; [request to download the data] * TNC [coral climate refugia]; [read a journal article about the data] * [Southeast Blueprint 2023 subregions]: Caribbean * [Southeast Blueprint 2023 extent] Mapping Steps * Convert the coral refugia data from vector to raster. * Reclassify the coral refugia ranks to above and below average values using the field “rank_PRU”. Lower values in the rank_PRU class correspond to higher resilience. Values ranging from 1-775 are considered above average, and values ranging from 776-1552 are considered below average. The rank of 0 is not assessed in the Puerto Rico/U.S. Virgin Islands portion of the coral refugia analysis, so treat it as NoData. * Mosaic together The Nature Conservancy’s benthic data for Puerto Rico and the Virgin Islands. * Reproject and do a majority resample of the benthic data to 30 m pixels. * Reclassify the benthic data to assign “Reef Crest” (1), “Fore Reef” (2), “Back Reef” (3), “Coral/Algae” (4) and “Spur and Groove Reef” (5) a value of 3; “Hardbottom Sparse Algae” (6) a value of 2, “Hardbottom Dense Algae” (7) a value of 1; and all other classes a value of 0. While conceptually “Boulders and Rocks” (11) would score more highly than the hardbottom sparse and dense algae classes, because algae have a negative impact on coral settlement, no boulders and rocks pixels occur in the TNC benthic data in Puerto Rico and the U.S. Virgin Islands. * Combine the above rasters and reclassify into the final indicator values seen below. * Clip to the Caribbean Blueprint 2023 subregion. * As a final step, clip to the spatial extent of Southeast Blueprint 2023. Note: For more details on the mapping steps, code used to create this layer is available [in the Southeast Blueprint 2025 Data Download] or [Caribbean-only Southeast Blueprint 2025 Data Download] under > 6_Code. Final indicator values Indicator values are assigned as follows: 5 = Coral with above average climate resilience 4 = Coral with unknown climate resilience 3 = Coral with below average climate resilience 2 = Hardbottom with sparse algae 1 = Hardbottom with dense algae 0 = Not coral or hardbottom Known Issues * While the benthic data was at a finer resolution than 30 m, the coral climate refugia analysis was at a 1 km2 resolution. This likely resulted in this indicator undervaluing or overvaluing a number of 30 m pixels at the edge of the 1 km2 squares. * For some pixels at the edge of the Caribbean Blueprint 2023 subregion, less than half of each 30 m pixel is covered by the finer resolution benthic data. These cells are classified as NoData in the final indicator. Disclaimer: Comparing with Older Indicator Versions There are numerous problems with using Southeast Blueprint indicators for change analysis. Please consult Blueprint staff if you would like to do this (email [hilary_morris@fws.gov]). Literature Cited Bonaldo RM, Pires MM, Guimarães PR Junior, Hoey AS, Hay ME (2017) Small Marine Protected Areas in Fiji Provide Refuge for Reef Fish Assemblages, Feeding Groups, and Corals. PLoS ONE 12(1): e0170638. [[https://doi.org/10.1371/journal.pone.0170638]]. Chollett I, Escovar-Fadul X, Schill, SR, Croquer A, Dixon AM, Beger M, Shaver E, McNulty VP, Wolff NH, Planning for resilience: Incorporating scenario and model uncertainty and trade-offs when prioritizing management of climate refugia. Global Change Biology. 2022; 28, 4054– 4068. [[https://doi.org/10.1111/gcb.16167]]. Environmental Protection Agency. Coral Reefs Fact Sheet. October 2005. [[https://archive.epa.gov/water/test/web/pdf/2007_6_28_oceans_coral_documents_coralreeffactsheet.pdf]]. Hoegh-Guldberg O, Pendleton L, Kaup A. People and the changing nature of coral reefs. Regional Studies in Marine Science. 2019; Volume 30,100699. [[https://doi.org/10.1016/j.rsma.2019.100699]]. Kleypas J, Allemand D, Anthony K, Baker AC, Beck MW, Hale LZ, Hilmi N, Hoegh-Guldberg O, Hughes T, Kaufman L, Kayanne H, Magnan AK, Mcleod E, Mumby P, Palumbi S, Richmond RH, Rinkevich B, Steneck RS, Voolstra CR, Wachenfeld D, Gattuso JP. Designing a blueprint for coral reef survival. Biological Conservation. 2021; Volume 257,109107. [[https://doi.org/10.1016/j.biocon.2021.109107]]. National Oceanic and Atmospheric Administration Coral Reef Conservation Program. 2020. Coral reef condition: A status report for Puerto Rico. [[https://icriforum.org/wp-content/uploads/2020/05/Puerto-Rico-English.pdf]]. Schill SR, McNulty VP, Pollock FJ, Lüthje F, Li J, Knapp DE, Kington JD, McDonald T, Raber GT, Escovar-Fadul X, Asner GP. Regional High-Resolution Benthic Habitat Data from Planet Dove Imagery for Conservation Decision-Making and Marine Planning. Remote Sensing. 2021; 13(21):4215. [[https://doi.org/10.3390/rs13214215]]. The Nature Conservancy. July 17, 2019. Stories in the Caribbean: New Hope for Coral Reefs. [[https://www.nature.org/en-us/about-us/where-we-work/caribbean/stories-in-caribbean/caribbean-a-revolution-in-coral-conservation/]].