Century-scale changes in reef ecosystems

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

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.                                                                                                                  

Millennial-scale changes in reef ecosystems

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, we have built the first photographic reference collection for modern reef fish teeth.

coring expeditions in Panama and Belize

Historical declines in threatened Acropora corals

I am leading a 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 Greenstein, Mary Donovan, Chelsea Korpanty, and Jeremy Jackson.


Patterns and causes of disparate trajectories of Caribbean reefs

By helping to compile and analyze nearly all the quantitative surveys conducted on Caribbean reefs over the past 40+ years,  I helped complete a comprehensive assessment by the Global Coral Reef Monitoring Network of the status, trends, and human drivers of differing reef ecological trajectories. Results of this large collaborative effort among many leading reef researchers were compiled into a report specifically created to inform reef managers across the Caribbean of the biggest threats to their reefs and targeted actions to maintain ecosystem resiliency. Specifically, this work revealed the important connection between high herbivorous fish and coral abundance, and our report therefore recommended that herbivorous fish catches in general (and fish traps and spearfishing in particular) are more stringently regulated.