Who knew that looking at old nautical charts could be the key to understanding the evolution of coral reef loss through the ages? But that’s just what a new study from Colby College, the University of Queensland and the Australian Research Council Centre of Excellence in Coral Reef Studies has based its research on. By comparing early British charts that sailors used in order to avoid shipwrecks to modern coral ecosystems, the team of scientists have been able to get a better glimpse of how coral reefs have changed over the years.
In addition to the 18th century nautical charts, the researchers used satellite data to analyze coral loss in the Florida Keys. Although most studies focus on the coral loss across smaller sections of the reef, this team used their resources to encompass a large geographic region.
"We found that some reefs had completely disappeared," Professor John Pandolfi from the University of Queensland said. The leader of the study, Loren McClenachan chimed in, "We found near the shore that entire sections of the reef are gone, but in contrast, most corals mapped further from land is still coral reef habitat today.”
Nevertheless, they found that 52% of the coral reef habitat mapped in the 1770s doesn’t exist today. Coral loss close to shore reached almost 90%."We found that reef used to exist in areas that today are not even classified as reef habitat anymore," Pandolfi said. "When you add this to the 75% loss of living coral in the Keys at that finer scale, the magnitude of change is much greater than anyone thought."
The team stresses that utilizing these old maps gives us a reality check of how much destruction we have caused in a relatively short period of time. That, they say, has impacted even our attitude towards conservation goals.
The study explains the significance of their results: “The near-complete elimination of the spatial coverage of nearshore coral represents an underappreciated spatial component of the shifting baseline syndrome, with important lessons for other species and ecosystems. That is, modern surveys are typically designed to assess change only within the species’ known, extant range. For species ranging from corals to sea turtles, this approach may overlook spatial loss over longer time frames, resulting in both overly optimistic views of their current conservation status and underestimates of their restoration potential.”