PARENT SESSION
Organized Oral Session 4: Tropical cyclone disturbance and forest dynamics at multiple temporal scales: results from long-term studies in the new and old worlds
Organizer(s): T Lin, H King, and SP Hamburg
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 511 B, Level 5, Palais des congrès de Montréal
An ecological pulse to quantify the effects of Typhoon Sudal on coastal ecosystems of Yap, Federated States of Micronesia.
MacKenzie, Richard*,1, Cormier, Nicole1, Kauffman, J.1, Ewel, Katherine1, Demopoulos, Amanda2, Iwomoto, Melissa3, 1 Institute of Pacific Islands Forestry, Honolulu, HI, USA2 Scripps Institution of Oceanography, La Jolla, CA, USA3 University of Hawaii at Manoa, Honolulu, HI, USA
ABSTRACT- The impacts of hurricanes on natural ecosystems have been documented through studies that have been primarily conducted in the Gulf of Mexico. Few studies have examined the ecological and physical effects of typhoons on small, isolated islands in the western Pacific Ocean, where human populations rely heavily on nearshore areas for subsistence. We conducted a research pulse in 6 different mangroves and adjacent ecosystems on the island of Yap, Federated States of Micronesia, 6 months after the island had been devastated by a category 3-4 typhoon (Typhoon Sudal). A summary of all research findings will be presented, with an emphasis on the nekton component of the pulse. Preliminary results revealed that fish densities were not significantly different among sites and community composition was dominated by demersal, Gobiidae species. Caridean shrimp densities decreased with increasing forest disturbance. Tree mortality in mangrove stands ranged from 3 to 31% with some variation among species. The amount of downed wood in post-typhoon mangrove stands was 2- to 4-fold greater than in pre-typhoon mangroves. Although soil redox potentials in gaps opened up by Typhoon Sudal were not significantly lower than in nearby intact mangroves, densities of sediment infauna were lower than in undisturbed mangrove sediments on other Pacific Islands. Infauna included opportunistic species typically found in heavily disturbed habitats (e.g., oligochaetes, capitellid polychaetes). Interviews conducted with members of the Yapese community revealed that many of the islanders were moving from the coastal areas to upland portions of the watershed. While this may provide protection for islanders from future storms and reduce coastal development pressures, increased development of watersheds could negatively impact adjacent mangroves and nearshore areas.
Key words: typhoon, mangroves, nekton, Pacific islands