Historical ecology of Caribbean coral reef ecosystems

I am reconstructing the baseline or “natural” state of Caribbean coral reefs and tracking changes in these ecosystems over the past millennium by utilizing an array of fossils preserved in reef sediments. The analysis of coral and mollusk remains collected in large pits I dug underneath modern reefs in Caribbean Panama showed that historical land clearing for banana agriculture has been significantly deteriorating reef environments for a century or more. My synthesis of archaeological  and historical data to track human impacts along the coastal zone of Caribbean Panama also shed light on why reefs along different parts of this coast are in such varying states today.

assortment1
subfossil mollusks used to assess environmental  change on reefs in Caribbean Panama

To expand the temporal, spatial, and taxonomic scope of my previous research, I am currently reconstructing a detailed timeline of change in Caribbean reef ecosystems over the past 1000 years.

This project is in collaboration with Richard Norris at Scripps Institution of Oceanography and Aaron O’Dea at Smithsonian Tropical Research Institute. By analyzing fish teeth, coral skeletons, and urchin spines collected in reef sediment cores from Caribbean Panama and Belize, I am assessing the impacts of historical fishing and coastal deforestation on reef ecosystem structure. This information will reveal the timing and causes of the recent dramatic decline of Caribbean reefs.  To identify reef fish teeth fossils found in the sediment cores to taxonomic and functional groups, I have built the first photographic reference collection for modern reef fish teeth.
KCramerPhotoWPipe

Belize cores
coring expeditions in Panama and Belize

I am leading a related project that combines fossil, early explorers’, and modern underwater survey data to track Caribbean-wide changes in threatened Acropora corals from the pre-human period to today.  This work shows that initial declines in these species from their pre-human levels first occurred in the 1950s—decades before coral disease epidemics that are cited as the original driver of decline—and were related to fertilizer consumption levels and human population density. This research demonstrates the urgent need for improved regulation of land based runoff, particularly of fertilizers and pesticides. My collaborators on this project are John Pandolfi, Ben GreensteinMary Donovan, Chelsea Korpanty, and Jeremy Jackson.

Acerv
threatened staghorn coral, Acropora cervicornis