DOI: 10.5061/dryad.dv41ns20w
title: Reef Life Survey data (fish and mobile invertebrate counts) from Carrie Bow Cay, Belize, 2015-2019

description: Aim Conservation efforts have traditionally addressed the threat of
 biodiversity loss by prioritizing regions and habitats with high endemic
 species richness. However, species-poor habitats often harbor distinct,
 valuable, and/or functionally unique species that contribute to regional
 diversity. In the tropical marine realm, the “mangrove-seagrass-coral reef
 continuum” has dominated both the scientific literature and marine spatial
 planning. Bare sediment habitats are also part of this continuum and often
 comprise the majority of bottom area, as they do in most regions
 worldwide, but are understudied and rarely considered in conservation. To
 address this information gap, we partition the relative contributions of
 five habitats in the coastal mosaic (forereefs, patch reefs, seagrass,
 mangroves, and bare sand) to fish diversity across a tropical seascape.
 Location Carrie Bow Cay, Belize Barrier Reef Methods Using diver visual
 censuses, we assessed fish community composition at three replicate sites
 from each of the five habitats annually for five years. We then
 partitioned diversity into within (α) and between (β) habitat
 contributions, and further partitioned β-diversity into components
 attributed to species replacement and richness difference. Finally, we
 determined the local contributions to β-diversity (LCBD) by each habitat
 and identified the key individual species behind these contributions. Main
 ResultsTropical sand flats were unique habitats, contributing
 disproportionately to total fish species diversity across the seascape,
 despite having the fewest species overall. Sand flats also had
 higher-than-expected local contributions to β-diversity (LCBD) and had the
 highest percentage of species not found in other habitats. Main
 Conclusions Our results demonstrate that previously understudied sand
 habitats harbor a relatively unique assemblage of species compared with
 other nearby habitats.  Marine spatial planning aimed at
 maximizing preservation of total biodiversity (including unique species)
 in the tropics should consider sand habitats.
description:   Data were collected by diver visual census
 using the Reef Life Survey protocol: https://reeflifesurvey.com/methods/.
 In brief, divers swam 10m wide x 5m high x 50m long transects working in
 teams of two, each diver surveying a 5m wide transect block. Divers
 counted and sized all swimming fish using Reef Life Survey "Method
 1." Then, in a second pass ("Method 2"), each diver
 surveyed a 1m wide block for cryptic fish and mobile invertebrates that
 reach an adult size of at least 2.5cm. Fish are placed into size bins, and
 invertebrates are counted but not sized. Three
 permanent sites were surveyed for each habitat across all five
 years.  Two seagrass sites, "Blueground
 Seagrass" and "Tobacco Seagrass" were each only surveyed in
 one year each. Taxonomic names were validated and
 classifications were assigned using the 'wormsbymatchnames'
 function within the 'worms' R package, which scrapes the world
 register of marine organisms database.
description: Each transect contains two 'blocks' (per Reef Life
 Survey methods) which are surveyed separately. We pooled the blocks for
 all analyses, as they are adjacent to one another and could not be treated
 as independent replicates. The 'scientific_name' column refers
 to the validated name used for analysis. The
 'orig_scientific_name' column refers to the original name
 recorded by the observer, which in some cases was a misspelling or
 unaccepted name that was changed during the taxon validation process. All
 numbered columns refer to size classes, and data are entered as a count of
 individuals within each size class, then totaled in the column
 'total_count.'   This information and more
 can be found in the ReadMe file attached.