DOI: 10.5061/dryad.40bv330
title: Data from: Scale‐dependent spatial patterns in benthic communities around a tropical island seascape

description: Understanding and predicting patterns of spatial organization across
 ecological communities is central to the field of landscape ecology, and a
 similar line of inquiry has begun to evolve sub‐tidally among seascape
 ecologists. Much of our current understanding of the processes driving
 marine community patterns, particularly in the tropics, has come from
 small‐scale, spatially‐discrete data that are often not representative of
 the broader seascape. Here we expand the spatial extent of seascape
 ecology studies and combine spatially‐expansive in situ digital imagery,
 oceanographic measurements, spatial statistics, and predictive modeling to
 test whether predictable patterns emerge between coral reef benthic
 competitors across scales in response to intra‐island gradients in
 physical drivers. We do this around the entire circumference of a remote,
 uninhabited island in the central Pacific (Jarvis Island) that lacks the
 confounding effects of direct human impacts. We show, for the first time,
 that competing benthic groups demonstrate predictable scaling patterns of
 organization, with positive autocorrelation in the cover of each group at
 scales &lt; ~1 km. Moreover, we show how gradients in subsurface
 temperature and surface wave power drive spatially‐abrupt transition
 points in group dominance, explaining 48 – 84% of the overall variation in
 benthic cover around the island. Along the western coast, we documented
 ten times more sub‐surface cooling‐hours than any other part of the
 coastline, with events typically resulting in a drop of 1 – 4°C over a
 period of &lt; 5 hr. These high frequency temperature fluctuations are
 indicative of upwelling induced by internal waves and here result in
 localized nitrogen enrichment (NO2 + NO3) that promotes hard coral
 dominance around 44% of the island's perimeter. Our findings show
 that, in the absence of confounding direct human impacts, the spatial
 organization of coral reef benthic competitors are predictable and
 somewhat bounded across the seascape by concurrent gradients in physical
 drivers.
description: Benthic community data
 from towed-diver surveys around Jarvis IslandBenthic community data
 collected via towed-diver surveys in March – April of 2006, 2008 and 2010
 for Jarvis Island. Divers were towed with instrumented boards at ~3 km h-1
 suspended ~1 m above the benthos at a target depth of 15 m. The tow boards
 were equipped with a high-resolution digital SLR camera. The percent cover
 of five functional groups, namely hard coral (split in to four
 morphological subcategories: plating, branching, free living, and
 digitate), crustose coralline algae (CCA), macroalgae, turf algae, and
 soft coral was extracted from each image using Coral Point Count software
 with Excel extensions. Column names as follows: PHOTOID- ID of individual
 photograph taken (month, day, year_tow number_photo number along that
 tow). ISLAND- The island the dataset is for, in this case JAR=Jarvis.
 DIVEYEAR- Year in which survey was conducted. LAT- Latitude and LON-
 Longitude of the camera position calculated from a layback model to
 accurately georeference each image position (WGS 1984). DEPTH- Depth of
 tow board (meters). TEMP- Temperature of tow board (degrees Celsius). The
 following are all percentage cover values for the major groups, BRAN-
 Branching coral, CCA- Crustose coralline algae, DIG- Digitate coral, MAC-
 Macroalgae, PLATE- Plating coral, SOFT- Soft coral, TURF-
 Turf.Towed-diver_surveys.xlsxSubmersible temperature recorder (STR) data from locations around Jarvis IslandRecords from five SBE 39 STRs used to quantify long-term intra-island gradients in reef-level temperature. Each STR recorded temperature (0.002 degrees Celcius accuracy) on an hourly basis between 2004 and 2010. The data is in NetCDF format, and contains two 1-dimensional variables, temperature (degrees Celsius) and time (days since 0001-01-01 00:00:00). Note that STRs 006 and 022 are the same station, the logger was serviced and replaced.Submersible_Temperature_Recorders.zipTotal nitrogen concentrations from locations around Jarvis Island during 2006Total nitrogen (NO2 + NO3) from water samples collected using a hand deployed 5 L Niskin bottle string at depths of 10 and 20 m (to match the depths of our benthic surveys – see below) at sites around the perimeter of Jarvis Island. Water samples (100 ml) were immediately pulled from each Niskin and frozen at -20 °C. The concentration of total nitrogen (NO2 + NO3) in each sample was later quantified at NOAA’s Pacific Marine Environmental Laboratories. Column names as follows: LOC- Location on compass bearing of sample around Jarvis Island. SITE- Site label. DEPTH- Depth of sample (meters). LAT- Latitude and LON- Longitude of the of the Niskin deployment (WGS 1984). TOTALN- The concentration of total nitrogen (NO2 + NO3).Nutrient_Concentrations.xlsx