Biscayne National Park offshore benthic habitat mapping project: Drafting, accuracy assessment and revisions

Estep, Andrew; Waara, Rorbert; Richter, Lee; Feeley, Michael; Patterson, Matt; Davis, Andy; Miller, Jeff; Witcher, Brian; Patterson, Judd; Vargas, Rachel

An accurate benthic habitat map is critical to survey design and monitoring efforts and, ultimately, the management of the marine resources. Recent advances in remote sensing technology such as sidescan/multibeam sonar, LiDAR, and high resolution aerial photography have enabled marine habitats to be mapped with greater detail, accuracy, and to greater depths. The 2011 benthic habitat map of the submerged resources of Biscayne National Park (BISC, Biscayne) was a collaborative effort between the Florida Fish and Wildlife Research Institute (FWRI), the South Florida Water Management District (SFWMD) and the National Park Service (NPS) South Florida/Caribbean Inventory and Monitoring Network (SFCN; the network). The primary goal of the map was to determine the current distribution and spatial patterns of benthic habitat resources in the offshore portion of Biscayne National Park east of Elliott Key. This map updates the previous benthic map of the Florida Keys reef tract developed by the Florida Marine Research Institute in 1998. Avineon, Inc. initially digitized the Biscayne benthic habitat map in ArcMap (Esri 2008) using aerial photos with 30-centimeter (cm; 11.8-inch [in]) horizontal pixel resolution and 27 field data points in 2008. A park-wide field assessment of the map found that it successfully delineated hard vs. soft bottom habitats, but map classes overall had an exact accuracy of 48.5% and an acceptable accuracy of 85.5% at the 90% confidence level (CL). The network utilized 3-meter (m) resolution 2008 LiDAR bathymetry and over 700 field data points from multiple sources to improve the precision of benthic polygons. The offshore portion of Biscayne was characterized using 14 mapping classes (Appendix A) based on Madley et al. (2002) and digitized in UTM, NAD83, zone 17N, using a 0.5-hectare (ha; 1.2-acres [ac]) minimum mapping unit (MMU) for all habitats. Where possible, patch reefs and soft-to-hardbottom interfaces were mapped to finer detail than the 0.5-hectare (1.2-ac) MMU. The benthic map is composed of 8,152 polygons which total 31,475 hectares (77,776 ac) All previously unknown areas (3,128 hectares [7,729 ac]) were mapped and classified. Each of the polygons in the map was individually inspected and adjusted if necessary. A subsequent accuracy assessment confirmed the revised benthic map met NPS accuracy standards with an exact accuracy of 80.2% (lower 90% CL=75.4%), and an acceptable accuracy of 94.4% (lower 90% CL=91.2%). The new benthic habitat map and corresponding datasets will serve as a new baseline inventory to support future studies and to facilitate management decisions within BISC. The accompanying DVD provides the Esri ArcMap project file; shapefiles; geodatabase containing polygon data, field data, accuracy assessment data, and park boundary data; various graphics of the park map and map tiles; imagery and LiDAR data used; and associated metadata.

Biscayne National Park offshore benthic habitat mapping project: Drafting, accuracy assessment and revisions

Series

Collections