The (scientific) question that drives the mapping is obviously important in determining the approach. Mapping reefs at coral-algal-sand level to assess the influence of climate on reef geomorphological structures would generally be a scale-mismatch in time and space (Hatcher et al. 1987). Mapping geomorphological structures to assess current reef health would be similarly inappropriate. It is therefore very important to state why images are processed and what functions/processes the maps will represent or symbolize.
The scope of the project is global. It intends to describe reefs in a way directly useful to scientists and managers by describing regional particularities and at the same time enable inter-region comparisons. Using a comparative approach, and by processing the entire continuum of reef structures and not only a few reefs, we expect that the horizontal patterns evidenced by remote sensing will highlight processes undetected by traditional field studies.
We expect that our products will help:
- Understand the global diversity and distribution of reef geomorphology: we will define regional typologies of reefs (end-members of reef structures) at geomorphological scales. End-members should reflect in priority antecedent geological control, high and low productivity/calcification zones, reef growth/erosion patterns, degree of aperture, exposure to dominant energy, exposure to land, and level of connections with other marine ecological systems (e.g. seagrasses, mangroves).
Examples of seascape and reef geomorphology.
Seascape and reef geomorphology explained.
- Build a global classification frame for all coral reef structures worldwide to enable comparisons and cross-referencing at this geomorphological level.
- Map the distribution of these end-members for each reef region.
- Estimate the extent of each end-member for each reef region worldwide. This will eventually provide a thematically rich global-scale estimate of coral reef extent.
- Understand how reef structures are controlled by regional scale factors at geological temporal scales.
- Revisit some predictions based on spatially poorly constrained data sets or based on simplifying assumptions in terms of reef complexity, extent and exposure to different hydroclimate.