This multi-agency project involved FWC-FWRI, NOAA, and Dade County. Each of the three regions had their data digitized in different manners. FKNMS used NOAA photogrammetrist and stereo analytical plotters. These plotter data were then converted into ARC-INFO. Biscayne Bay aerial photos were digitized by Greenhorne and O'Mara using stereo analytical plotters. Florida Bay data was digitized by NOAA-CSC in Charleston, SC by scanning the photos and the linework overlays. The classification system was the same for all three regions. A hard copy atlas and CD-ROM titled "Florida Marine Research Institute Technical Reports-Benthic Habitats of the Florida Keys", were created by the FWC-FWRI and NOAA. These data were edited in summer 2001 to correct attribute errors. The Florida Bay data was added to the layer at that time as well.
Prior to July 1, 2004, the Fish and Wildlife Research Institute (FWRI) was known as the Florida Marine Research Institute (FMRI). The institute name has not been changed in historical data sets or references to work completed by the Florida Marine Research Institute. The institute name has been changed in references to ongoing research, new research, and contact information. This layer is the old coverage "fknms_ben_92" combined with the Florida Bay extent.
THE DATA INCLUDED IN FGDL ARE "AS IS" AND SHOULD NOT BE CONSTRUED AS LEGALLY BINDING. THE UNIVERSITY OF FLORIDA GEOPLAN CENTER SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED AS A RESULT OF USING, MODIFYING, CONTRIBUTING OR DISTRIBUTING THE MATERIALS.
A note about data scale:
Scale is an important factor in data usage. Certain scale datasets are not suitable for some project, analysis, or modelling purposes. Please be sure you are using the best available data.
1:24000 scale datasets are recommended for projects that are at the county level. 1:24000 data should NOT be used for high accuracy base mapping such as property parcel boundaries.
1:100000 scale datasets are recommended for projects that are at the multi-county or regional level. 1:125000 scale datasets are recommended for projects that are at the regional or state level or larger.
Vector datasets with no defined scale or accuracy should be considered suspect. Make sure you are familiar with your data before using it for projects or analysis. Every effort has been made to supply the user with data documentation. For additional information, see the References section and the Data Source Contact section of this documentation. For more information regarding scale and accuracy, see our webpage at: <http://geoplan.ufl.edu/education.html>
Other habitats-such as seagrass beds, hardbottom communities, and bare substrate-are less stable than coral reefs. These benthic features are positionally accurate to within 10 m.
Physical factors such as water currents and hurricanes and biological factors such as seasonal growth and die-off affect the distribution and stability of these benthic habitats along the ocean's floor. Plant densities within seagrass communities may increase or decrease over a period of months or years. Hardbottom habitats may become covered by sediment and then by seagrasses.
Data was generated by FWRI and NOAA staff, along with ecologists contracted by NOAA and FWRI. The aerial photographs used in producing the maps were taken and digitally compiled by NOAA's NGS staff. Contracted ecologists and FWRI staff developed the classification scheme. FKNMS staff provided support for the photo interpretation, delineation, and ground-truthing activities and for reviewing the benthic classifications. NGS staff digitally compiled the photographic information. Staff from Strategic Environmental Assessments (SEA) division of ORCA converted the NGS digital files into a Geographic Information System (GIS) and then performed QA/QC on those files. Staff from both FWRI and NOAA's Ocean Resources Conservation and Assessment (ORCA), which is now part of the National Ocean Service, designed and produced the atlas.
Aerial Photography Natural-color aerial photographs of the Florida Keys region were taken by NOAA's Remote Sensing Division during flights made from December 1991 through April 1992. A Wild RC-30 camera mounted in a Cessna Citation II Fanjet aircraft was used. The source photography had a nominal photo scale of 1:48,000 (1 cm = 480 m). Each photograph covered an area of approximately 160 km2. An 80% endlap and 60% sidelap of adjacent photographs ensured that coverage would be complete and that an adequate number of reference locations would be present for photogrammetric measurements. Approximately 450 photos provided monoscopic coverage and were used to delineate benthic habitats.
Establishing a Habitat-Classification Scheme: Two recognized ecologists, both with local knowledge of the Florida Keys and extensive expertise in marine habitats, along with FWRI staff, developed the hierarchical classification scheme used in this atlas. The habitat-classification scheme is composed of 24 classes of benthic communities in 4 major habitat categories: corals, seagrasses, hardbottom, and bare substrate. Dredge zones, banks, and restoration areas located within these communities are also denoted. Photointerpretation Photos were interpreted by the two ecologists and FWRI staff. They determined and then delineated the types of benthic habitats found in the aerial photos. The minimum habitat area delineated was 0.5 ha. However, patch reefs (herein considered part of the coral reef benthic habitat) of less than 0.5 ha were delineated as points. Ground-truthing was conducted to verify that benthic habitats were properly identified on the aerial photographs. Researchers were able to ground truth most benthic communities while snorkeling; scuba gear enabled them to ground truth for those communities located in deeper or turbid waters. Field information about the benthic habitat and site GPS locations was recorded. The ecologists and FWRI staff reviewed photos for content and accuracy and then sent them to NOAA for digital compilation.
Digital Compilation of Aerial Photographs: NGS cartographers inspected each photograph for completeness of delineations, photo discrepancies, and areas of turbidity. Cartographers used a stereographic analytical plotter with NOAA's in-house software to digitize and label the benthic communities and shoreline features seen on the aerial photos. In many cases, the cartographers were able to provide additional detail because of the three-dimensional views permitted by the analytical plotter. The compiled data were checked by NGS staff. Quality Control - Data were reviewed in three phases: 1) a review of digital data to ensure line and attribute completeness, 2) a comparison between the 1:48,000-scale maps of the compiled data and the original source photos, and 3) a comparison between the 1:24,000-scale maps of the compiled data and the original delineated photos to determine the positional accuracy of polygonal shapes and attributes.
Positional Accuracy Standards - Aerial photographs used to generate the digital data for the maps in this atlas were taken between December 1991 and April of 1992. Thus, the atlas represents the distribution of benthic habitats in the Keys over this time period. The horizontal accuracy of well-defined points (clearly identifiable, immobile objects such as the tops of radio towers or the corners of wharves) is within 2 m. The horizontal accuracy of continuous data (e.g., benthic habitats) ranges from 5 to 10 m, depending on the habitat class. Certain benthic features, such as patch reefs and spur-and-groove reefs, have a horizontal accuracy of 5 m. These habitats are composed of massive rock and coral formations that are stable in position over time and are resistant to all but the most powerful physical forces. Coral reefs, once established, tend to remain for decades or centuries. Other habitats-such as seagrass beds, hardbottom communities, and bare substrate-are less stable. These benthic features are positionally accurate to within 10 m. Physical factors such as water currents and hurricanes and biological factors such as seasonal growth and die-off affect the distribution and stability of these benthic habitats along the ocean's floor. Plant densities within seagrass communities may increase or decrease over a period of months or years. Hardbottom habitats may become covered by sediment and then by seagrasses.
GIS Data Layers: To ensure that the digital data sets in this atlas were accurate in position and attribution, SEA staff used a series of data-translation and topology-construction steps while incorporating the data into a GIS, a sophisticated computer mapping and analysis software. All the individual GIS digital data sets were then combined to form several regional mosaics. Each region's data set was sent to FWRI for final quality control and assembly. FWRI inspected these data sets to ensure that no errors remained. The regional data sets were then joined together to make an FKNMS-wide, benthic-habitat data set. The resulting data set was inspected one last time, with particular scrutiny paid to the regions of overlap, where errors would most likely occur. The delineated aerial photos were referred to at every step of this process. Summer 2001 Florida Bay area was added using similar methodology in 2001
During the GeoPlan QA/QC process, the following changes were made to the data: (1) Added DESCRIPT item based on DESCRIPTIO
I. Coral Reefs A. Patch Reefs Discrete coral communities, typically dome-shaped, usually outside of Hawk Channel, with a few inshore. Can be linear features where several or a series occurs. Mostly off Key Largo and Elliot Key (5,000) with a few off Big Pine, near Key West, and at the Dry Tortugas. Usually composed of hard corals Montastraea sp., Siderastrea sp., Diploria sp., and Colpophyllia sp.. Often surrounded by a whitish appearing halo. 1. Individual patch (CPI) Isolated, as small as visible on aerial, with or without a halo. 2. Aggregated patch reefs (CPA) More than one, usually too close together to map individually or where halos coalesce. 3. Halo (CPH) Barren, essentially unvegetated, variable, whitish zone around patch reef resulting from grazing activity of urchins and fishes. Rubble from weathering of patch reef may allow attachment sites for corals to expand the colony. Not always present or large enough to be mapped. 4. Individual Patch Reef and Halo (CPIH) Patch reef and halo combination too small to delineate. Separate delineations of reef and halo to be done by NOAA Photogrammetry.
B. Platform Margin Reef Generally the "reef tract" or "barrier reef". Extends from northern boundary of FKNMS to west of the Marquesas Keys and also found at the Dry Tortugas. Diverse communities variable in morphology and species composition. Both high and low relief. Includes all coral/hardbottom features distinguishable from "patch reefs". 1. Spur and Groove a. Shallow (eg. Looe Key) (CPSS) Well developed systems on "fore-reef" at major bank reefs on reef tract, with vertical relief to about 4m. Actively growing upward and outward. Distinctive signature on aerial photography due to shallow water (0 - 10m) and high vertical relief. Linear length to approximately 1000m or more(?). b. Drowned (Transitional = older, drowned) (CPSD) Older, not actively growing (probably eroding) features often being buried by sand migration from shallower zone of reef tract. Nearly typical spur and groove signature in aerial photos, but sometimes with less resolution or definition. Usually low profile, about 0.5 - 1.5m. Visible to interpretable depth of photography (15m~). Often greater linear length than shallow spur and groove. 2. Remnant - Low profile (CPR) Coral/hardbottom features not exhibiting distinctive signature of spur and groove reefs. Usually parallel to line of reef tract but may form transverse features perpendicular to the reef tract. Relief from less than 0.5m - 1 or 2m. 3. Coral Patches in Bare Sand (CPB) Very sparse features that are similar in nature to patch reefs but are on the outer reef tract. These areas are dominantly sand or a veneer of sand over low relief rock. Scattered throughout are small patches ranging from a single gorgonian, sponge, or small coral head up to a low assemblage that may be a few meters to 10m across. These patches make up a low percentage of the total cover, yet are distinctive. Thus far this class is found mainly in the area from Big Pine Shoal to Sombrero Light, and may be associated with the lack of a developed forereef structure in this area. 4. Back Reef (CB) Shallow (<2m) platform landward of spur and groove features on bank reefs, typically rubble zone colonized with numerous soft corals and pioneering staghorn, fire coral and other hard corals. Corals here are widely spaced individuals on a rubble platform. 5. Reef Rubble (CR) Zone landward of bank reefs and other high energy reef tract areas where unstable rubble exists with little or no visible colonization. In relatively shallow water (1 - 6m) often in association with Thallassia or Syringodium. Signature on the aerial photos are distinctive from other coral/hardbottom communities. May form transverse features perpendicular to line of reef tract.
II. Hardbottom (Inshore only, stops at Hawk Channel for FKNMS) Solid, flat, low-relief substrate composed of Key Largo limestone (from west end of the Newfound Harbor Keys off Big Pine to the north edge of the FKNMS) or Miami oolite(Big Pine Key and west). Depth ranges from intertidal to approximately 7m in deep tidal channels and the inside edge of Hawk Channel. May include a thin veneer of carbonate sand or mud, too thin and unstable to support seagrass. A. Soft Coral, Hard Coral, Sponge, Algae (HC) Benthic community (no perceptible seagrass) is variable and typically a function of sediment, water, depth, and exposure to wind and current. May also include solitary hard corals, Porites sp., Sideratrea sp., and Manicina sp.. shallowest zones (<1m) may include only attached or drift algae, soft corals are usually more common in deeper zones.
B. Hardbottom with perceptible seagrass (<50%) (HS) Usually in patches, seagrasses occur in depressions and basins where adequate sediment has accumulated, but constitute <50% bottom coverage. Hard bottom may include solitary hard corals and soft corals, but most often sponges and benthic algae (attached or in draft).
III. Bare Substrate Open and essentially unvegetated with no benthic community visible on photos due to unstable nature of substrate. Can be large seagrass blowouts or active erosional features. Largest areas are on reef tract, in the bottom of Hawk Channel, and west of the Marquesas Keys. May have sparse, ephemeral benthic algae or diatom films that are not detectable on photography. Diatom films may develop in a few days. A. Carbonate Sand (usually exposed locations) (BS) Sand-size carbonate sediments usually in areas exposed to current and wind energy that continually sorts out and removes finer fractions. B. Carbonate Mud (usually protected location) (BM) Fine carbonate sediments in deep water (Hawk Channel) or locations protected from wind and wave energy. More depositional than erosion. C. Organic Mud (BO) On windward shorelines where drift seagrass and algae builds up in intertidal and shallow water. Continual deposition and resuspension of organic matter limits development of benthic community on natural as well as disturbed shorelines. Especially common feature on windward shorelines of Big Pine, No Name, and Little Pine Keys.
IV. Seagrass A. Moderate to Dense, continuous beds (SD) Solid, continuous Thalassia, Syringodium, and Halodule, individually or in mixed beds. Widespread in occurrence with range in depth from intertidal (bank) to about approximately 10m. B. Moderate to Dense, nearly continuous beds (seagrass>50%), with blowouts, and/or sand or mud patches. (SDB) Solid, continuous Thalassia or Syringodium, rarely Halodule, individually or in mixed beds. Widespread in occurrence with range in depth from intertidal (bank) to approximately 10m. Moderate to high-energy regimes. Here blowouts or patches are dispersed as holes in otherwise continuous seagrass beds. Usually on reef tract and near entrances to tidal channels and passes. A common habitat in back country of middle keys with large water movements between the Gulf and Atlantic. C. Sparse, continuous beds (SS) Areas where seagrasses occur in low density (<~50 shoots/m sq.), typically in shallow protected bays where physical conditions or substrate limits development. May be hard to distinguish signature on aerials from barren bottom, requiring ground-truthing. D. Patchy Typically the result of depressional basins or creek-like features in seabed that accumulate sediment or contain organic peat deposits from mangrove community occurring during lower sea level. This greater depth of sediment allows seagrass development in an area, or allows denser seagrasses compared to surrounding areas. Widespread features in inshore areas throughout the FKNMS and Biscayne Bay. 1. Dense patches of seagrass (>50%) in a matrix of Hardbottom. (SPH) One of the most common categories, patches occur in areas where a thin sediment layer over flat natural rock precludes development of seagrasses. often numerous in number, highly visible on aerial photos. 2. Dense patches of seagrass in a matrix of sparse seagrass. (SPS) Depressional features with deep sediment allow denser development of seagrasses than on surrounding bottoms where only a thin layer may be present. May be difficult to discern on aerials from seagrass patches in hardbottom, may occur more in deeper water or protected bays. 3. Dominantly sand or mud with small, scattered seagrass patches (<50%). (SPP) Large sand features with recognizable seagrass patches, similar location to seagrass with blowouts. Substrate may vary from sand to mud, and algae, either fixed or drift may be a significant component. Offshore features tend to be sandier, and inshore protected areas tend to be muddier in composition. 4. Largely Macroalgal cover with scattered seagrass patches. (SPA) Scattered seagrass patches are a significant habitat component, but dominant is background of macroalgae. Algal cover is banks of Halimeda sp. or Pencillus sp. may be difficult to delineate without ground-truthing.
V. Miscellaneous A. Tidal creeks (T) Natural features, typically meandering water bodies confined by mangrove shorelines. May be short and leading to interior bays or lagoons, or many miles long and narrow dividing an island. On occasion overhanging mangroves may obscure the water surface of a creek to be mapped.
VI. Special Modifiers Special Modifiers are attached to a specific community type when applicable. Ex. Sdb, Bud, etc. A. Banks (Xb) Intertidal seagrass and some hardbottom communities, even if only intertidal at spring low tides, often open water features or extending out from a shoreline. Distinctive signature on aerial compared to surrounding bottom. Sometimes burned off patches are present on bank top. If these patches become large enough, they are mapped as separate bare areas. B. Dredged/Excavation (Xd) Those situations where dredging or excavation has occurred, channels, rock mines, and anchorages. C. Restoration (Xr) Site of fill removal or backfilling of dredged area to restore original elevations and intertidal or benthic community. Modifier applied to resulting benthic community. Local knowledge of restoration sites necessary.
VII. Unmappable/Uninterpretable (U) This refers to those areas that are beyond the depth threshold of the aerial photography (approximately 30ft), and/or uninterpretable due to glare, or turbid waters. Most narrow or deep access channels such as Key West Harbor, Hawk Channel, or the deeper sides of the reef tract. Minimum mapping unit = 0.5 hectare (1 acre) for all habitat. Patch reefs may be <0.5 ha.