Spatial diversity of a coastal seascape: Characterization, analysis and application for conservation
Recent conservation approaches have focused on the landscape as either a conservation target or a mechanism by which conservation can be achieved. A seascape is a spatially heterogeneous surface that is generally represented as a mosaic of patches (homogeneous units of natural vegetation) with spatial and functional relationships that are organized as puzzle pieces, which represent one or several ecosystems. Spatial analysis using a landscape ecology approach offers a wide range of tools to study, monitor, manage, and conserve these areas. The objective of this study was to identify the benthic community and spatially characterize the submarine habitats of the shallow coast along the Yucatan, Mexico, to identify priority conservation areas. The study area was divided into 3 zones based on their environmental qualities, and a total of 290 sampling sites were defined from a stratified random sample based on the unsupervised classification of Landsat ETM+ images. For each site, a video was taken; the substrate type was identified; and the organisms present were identified to the lowest possible taxonomic level. Training groups were defined by ordination analysis for the supervised classification of spectral bands and bathymetric modeling to obtain maps of the seascape, and the composition and configuration of the seascape were analyzed using spatial diversity metrics and indices. A total of 40 benthic morphotypes, predominantly brown algae and seagrass, were identified. Seven habitat types were defined along the coast based on the arrangement and spatial organization of the benthic community: bare substrate (A), sand with seagrass (B), seagrass meadow (C), seagrass with macroalgae (D), macroalgae on sand (E), flagstone with macroalgae (F), and macroalgal forest (G). The spatial configuration of the coastal seascape reflected the geomorphological characteristics of the study area and was significantly different among the three zones. Habitats G and F were present everywhere along the coast and dominated the seascape, whereas habitat C only occurred in Zone 3. Due to their structural complexity and biological richness, habitats C, D, F, and G are potentially critical for turtle, grouper, octopus, and lobster species, so these habitats are suggested as priority conservation areas to promote the conservation of these species as well as the productivity and functionality of these ecosystems.