By Sally Willig, Lecturer & Advisor Master of Environmental Studies

University of Pennsylvania

December 10, 2019


Male coqui (Eleutherodactylus coqui) guarding eggs near Sabana Field Station (by author, 4 March 2019)

Puerto Rico’s diverse ecosystems derive from its varied climate, geology, topography, and disturbance history (Gould et al. 2008; Miller and Lugo 2009). Over the past several spring breaks (2015-17, 2019), students in ENVS607: Field Study of Puerto Rico’s Ecology have explored this diversity in protected natural areas and learned about research, management, and conservation efforts. The most recent trip revealed the effects of and recovery from back-to-back Hurricanes Irma (6 Sept.) and Maria (20 Sept.) in 2017 (Pasch, Penny, and Berg 2019). 

The first base for exploration is the United States Forest Service (USFS) Sabana Field Station in El Yunque National Forest, the wettest (>200” of rainfall annually in highest elevations) location situated on steep slopes of volcaniclastic rock and a quartz diorite intrusion.  Hurricane Maria’s high winds defoliated the forest and damaged structures including the Tropical Responses to Altered Climate (TRACE) experiment that involves warming vegetation and soils in a patch of wet tropical forest 4 degrees Celsius above ambient temperature ( By March of 2019, forested slopes were green, winding mountain roads to the highest trailheads were repaved, and repairs had been made to the TRACE experiment.  Students interacted with researchers to learn about the warming experiment. On night hikes near the field station, students spotted assorted fauna including a male coqui (Eleutherodactylus coqui) guarding a cluster of eggs. On a walk to an early successional fern-covered hillside, Dr. Joseph M. Wunderle, Jr., a USFS ornithologist, shared his research on the effects of Hurricanes Irma and Maria on birds in northeastern Puerto Rico (Wunderle 2017). On the classic hike to El Yunque Peak we saw a more open canopy and lush shrub and herbaceous growth in the palm brake forest and, at the highest elevation, in the enchanting fog enshrouded elfin cloud forest. 

Descending to the nearby coast, students met Cristobal Jimenez, President of the Northeast Ecological Corridor Coalition ( which advocated to protect seven miles of coastline from Luquillo to Fajardo that was slated for resort development and provides critical leatherback turtle nesting habitat. On an evening trip into Laguna Grande, a bioluminescent bay, we kayaked through a stand of dead red mangrove (Rhizophora mangle) affected by Hurricanes Irma and Maria, the latter of which made landfall on the nearby southeast corner of the island.  Stands of red mangrove, a species that is more susceptible to wind damage than black mangrove (Avicennia germinans), recover through seedling growth as the species is unable to resprout  (Imbert 2018).

Moving clockwise around the island, we investigated a remnant Pterocarpus swamp nestled in the sprawling Palmas del Mar Resort and preserved through a conservation easement between the Palmas del Mar Homeowners’ Association and the Puerto Rico Conservation Trust.  Largely drained for sugarcane production where it historically occurred on the coastal plain, this rare freshwater swamp supports tall curving buttressed trunks of swamp bloodwood (Pterocarpus officinalis) and a dense herbaceous layer of tall ferns.  Hurricane-force winds devastated the swamp (see photos here,  However, a year and a half later, bare, broken trunks had resprouted, the lush fern cover had returned, and the boardwalk had been repaired.

Damaged boardwalk and downed and dead trees in a mangrove swamp at Jobos Bay NERR (by author, 6 March 2019)

Continuing southwest, we stopped at Jobos Bay National Estuarine Research Reserve (NERR) and hiked with Angel Dieppa, Research Coordinator, to a salt flat and surrounding mangrove swamp where storm surge had upended a boardwalk, downed trees, and transported red mangrove seedlings inland.  Standing on the north shore of Jobos Bay, habitat for the Federally Threatened Antillean Manatee (Trichechus manatus manatus)  that feeds in seagrass beds, we learned about the controversial AES coal burning power plant that rose in the distance on the far side of the bay ( 

Mary Lee’s by the Sea in Guanica, the driest (36” of rainfall annually) location underlain by limestone along the Caribbean Sea, provides the second base for exploration including kayaking along fringing red mangroves and hiking through dry tropical forest that provides habitat for a great diversity of birds as well as the Federally Threatened Puerto Rican Crested Toad (Peltophryne lemur) which emerges from rock crevices in the wake of heavy rains and breeds in temporarily flooded pools. 

Luis Villanueva-Cubero, a PhD candidate currently working in National Disaster Recovery Support for Federal Emergency Management Agency (FEMA), has been our guide and good friend on every trip.  We learned about the work he and fellow FEMA employees are doing to help communities recover from Hurricane Maria on a visit to Laguna Cartagena National Wildlife Refuge which contains a remnant of the once-extensive freshwater lagoon that was drained for agriculture.  On our last field day, we met Luis at Playas Punta Borinquen adjacent to a Spanish lighthouse that toppled during the 1918 earthquake and learned about a proposal to establish a Northwest Biological Corridor. Luis informed us about the community effort, Rescate Playas Borinquen (, working to provide public access to the coastal land including a moist coastal forest on limestone that we hiked through.

Puerto Rico’s protected natural areas afford the opportunity to see a diversity of ecosystems occurring in wet, moist, and dry areas on different bedrock and with different disturbance histories. These ecosystems have evolved with periodic hurricanes and have adaptations for recovery, however, there is concern about the increasing frequency and intensity of these events. Grass-roots efforts to protect the Northeast Ecological Corridor and other areas such as the Northwest Biological Corridor are essential.  As communities continue to recover from Hurricane Maria’s destruction, preparation for future hurricanes is of paramount importance especially with regards to reliable provision of power, water, and food to residents throughout the island. 


Works Cited

Gould, W.A., Jimenez, M.E., Potts, G.S., Quinones, M., Martinuzzi, S., 2008, Landscape units of Puerto Rico: Influence of climate, substrate, and topography, Scale 1: 260,000. IITF-RMAP-06, Rio Piedras, PR: US Department of Agriculture, Forest Service, International Institute of Tropical Forestry

Imbert, D., 2018, Hurricane disturbance and forest dynamics in eastern Caribbean mangroves, Ecosphere, Vol. 9, Issue 7

Miller, G.L. and Lugo, A.E., 2009, Guide to the Ecological Systems of Puerto Rico, General Technical Report IITF-GTR-35, San Juan, PR: US Department of Agriculture, Forest Service, International Institute of Tropical Forestry, 437 pages.

Pasch, R.J., Penny, A.B., and Berg, R., 14 February 2019, National Hurricane Center Tropical Cyclone Report: Hurricane Maria (AL152017) 16-30 September 2017, NOAA, NWS

Wunderle, J.M., Jr., 2017, Effects of Hurricanes Irma and Marie on Birds in the Fajardo Christmas Bird Count in Northeastern Puerto Rico: A Preliminary Assessment, Acta Cientifica, 31 (1-3): 18-33


Dr. Sally Willig teaches Wetlands, Field Study of Puerto Rico’s Ecology and Regional Field Ecology in the Master of Environmental Studies program with the aim of getting students into the field to better understand ecosystem processes and patterns. She also advises students concentrating in Environmental Biology, Resource Management, and Environmental Education and Advocacy, and finds great satisfaction in helping students achieve academic and professional goals. Sally has her AB in Geology from Princeton University and a PhD in Geology from the University of Pennsylvania.