Spatial Analyses of Benthic Habitats to Define Coral Reef Ecosystem Regions and Potential Biogeographic Boundaries along a Latitudinal Gradient

Abstract

Marine organism diversity typically attenuates latitudinally from tropical to colder climate regimes. Since the distribution of many marine species relates to certain habitats and depth regimes, mapping data provide valuable information in the absence of detailed ecological data that can be used to identify and spatially quantify smaller scale (10 s km) coral reef ecosystem regions and potential physical biogeographic barriers. This study focused on the southeast Florida coast due to a recognized, but understudied, tropical to subtropical biogeographic gradient. GIS spatial analyses were conducted on recent, accurate, shallow-water (0–30 m) benthic habitat maps to identify and quantify specific regions along the coast that were statistically distinct in the number and amount of major benthic habitat types. Habitat type and width were measured for 209 evenly-spaced cross-shelf transects. Evaluation of groupings from a cluster analysis at 75% similarity yielded five distinct regions. The number of benthic habitats and their area, width, distance from shore, distance from each other, and LIDAR depths were calculated in GIS and examined to determine regional statistical differences. The number of benthic habitats decreased with increasing latitude from 9 in the south to 4 in the north and many of the habitat metrics statistically differed between regions. Three potential biogeographic barriers were found at the Boca, Hillsboro, and Biscayne boundaries, where specific shallow-water habitats were absent further north; Middle Reef, Inner Reef, and oceanic seagrass beds respectively. The Bahamas Fault Zone boundary was also noted where changes in coastal morphologies occurred that could relate to subtle ecological changes. The analyses defined regions on a smaller scale more appropriate to regional management decisions, hence strengthening marine conservation planning with an objective, scientific foundation for decision making. They provide a framework for similar regional analyses elsewhere.

Determining the Extent and Characterizing Coral Reef Habitats of the Northern Latitudes of the Florida Reef Tract (Martin County)

“…Hardbottom habitats were sparse outside of a shallow, near shore area around St. Lucie Inlet and a few thin deep ridge lines (Figure 1). Although not confirmed by coring, these features are thought to be cemented beach dunes submerged during the last Holocene sea level transgression [12], [33]. The most extensive deep hardbottom was the northern end of the Deep Ridge Complex which extends from Palm Beach into southern Martin for about 2 km before it is covered with sediment.…”

Novel Method for Interpreting Submarine Geomorphology from Laser Airborne Depth Sounding (LADS) Bathymetry using Surfer®12 Shaded Relief Maps

“…Figure 10 demonstrates the cognitive interpretation results made possible by this methodology. Walker (2009Walker ( , 2012; and Walker, Riegl, and Dodge (2008). The same data are also amenable to automated machine classifications (Finkl and Makowski, 2015) and the Geospatially Integrated Seafloor Classification Scheme (G-ISCS) (Makowski, Finkl, and Vollmer, 2015).…”

“…Examples of such efforts to map shelf geomorphology and biophysical environments using high-density airborne laser bathymetry derived imagery may be found in Brock and Purkis (2009);Bukata et al (1995); Deronde et al (2008);Finkl andAndrews (2008, 2009);Finkl and Banks (2010);Finkl, Benedet, andAndrews (2004, 2005a,b); Finkl and Makowski (2015); Finkl and Vollmer (2011) Klemas (2011a,b,c); Long, Angelo, and Weishampel (2011);Penny, Billard, and Abbot (1989); Stockdon, Doran, and Sallenger (2009) ;Stockdon et al (2002); Stoker et al (2009);Walker (2009Walker ( , 2012; and Walker, Riegl, and Dodge (2008), among others. Although the resolution of LADS derived imagery is very adequate (i.e.…”

Genotype and attachment technique influence the growth and survival of line nursery corals

“…Six line nursery structures, hereafter referred to as lines, were installed at an existing Acropora cervicornis nursery off Fort Lauderdale, Florida, in January 2011. The nursery occupied a sand channel between the nearshore ridge complex and inner reef of the region at a depth of 7 m (Walker ). Each nursery line (made using 3/8″ polyester nautical rigging line) consisted of a 2 m horizontal line suspended 1 m above the substrate and two vertical lines (Fig.…”