Document Type

Article

Publication Date

9-2008

Publication Title

Journal of Coastal Research

Keywords

Coral reefs, Acoustic mapping, Aerial photography, Bathymetry, Echoplus, Florida, GIS, Habitat mapping, LADS, LIDAR, QTC

ISSN

0749-0208

Volume

24

Issue/No.

5

First Page

1138

Last Page

1150

Abstract

To create maps of nearshore benthic habitats of Broward County, Florida, from 0 to 35 m depth, we combined laser bathymetry, acoustic ground discrimination, subbottom profiling, and aerial photography data in a geographic information system (GIS). A mosaic of interpolated, sun-shaded, laser bathymetry data served as the foundation upon which acoustic ground discrimination, limited subbottom profiling and aerial photography, and groundtruthing data aided in interpretation of habitats. Mapping criteria similar to NOAA biogeographic Caribbean mapping were used to allow for a comparable output. Expert-driven visual interpretation outlined geomorphological features at a scale of 1 : 6000 with a minimum mapping unit of 1 acre. Acoustic data were then used to differentiate areas of similar geomorphology by their acoustic diversity into areas of high and low scatter, which could be equated to rugosity created by either the substratum or benthic fauna. Of the approximately 112 km² mapped, 56.62 km² were coral reef and colonized hard bottom (50.42%), 54.78 km² were unconsolidated sediments (46.80%), and 0.43 km² were other categories (2.78%). Three linear reef complexes exist. The outermost linear reef has a mature windward reef morphology including a drowned spur and groove system, which was absent on the other two reef lines. The acoustic ground discrimination and groundtruthing showed different benthic habitats on the outer vs. middle and inner reefs. Higher acoustic scatter could be related to taller benthos and more rugose substratum. A considerable amount of colonized pavement (nearshore hard grounds) was found inshore. The map of Broward County yielded a high overall accuracy of 89.6%, only slightly less than the photo-interpreted NOAA Caribbean maps (overall accuracy of 91.1%). User and producer accuracies within each category were also similar. The combined technique approach was effective and accurate, and similar methodology can be used in other areas where photo interpretation is not feasible because of turbidity or depth limitations.

Additional Comments

NOAA award #: NA160Z2440

ORCID ID

0000-0002-6003-9324

ResearcherID

F-8807-2011

DOI

10.2112/06-0809.1