How do long-term changes in freshwater flow control the magni- tude of nutrient and organic-matter inputs to the estuarine zone?
How will human- induced changes in nutrient enrichment, together with these changes in hydrology, affect patterns and mag- nitudes of primary and secondary production in diverse types of coastal settings?
How will these direct impacts by cultural eutrophication interact with long-term changes in climate drivers (sea- level rise, hurricanes, fires) to modify ecolog- ical patterns and pro- cesses across different coastal settings? Any application of the
approach and research agenda proposed here to carry on long-term ecolog- ical studies in the Caribbean will need to take into con- sideration the financial re- quirements of the study and the strong cultural and po- litical differences among all nations forming the wider Caribbean region. One of the major impediments to reducing environmental degradation of the Carib- bean Sea is the complex process needed to establish a regional management plan for marine resources. Richards and Bohnsack (1990) pointed out more than a decade ago that the real problem was the lack
Figure 5. Proposed research questions along an upstream-downstream salinity gradient encom- passing marshes, mangroves, sea grasses, and
(continued on next page)
Freshwater and brackish marshes
How do differences in freshwater flow modify the spatial distribution of wetlands in the upper regions of the watershed?
What is the nutrient (phosphorus and nitrogen) removal capacity of wetlands around agricultural and urban areas?
What changes in species community composition and pro- ductivity occur in response to an increase in nutrient loads?
How does the quality and quantity of organic matter change along a hydrological gradient from freshwater marshes to mangrove forests?
Does aboveground (wood, litterfall) and belowground productivity change in response to differential nutrient enrichment (phosphorus versus nitrogen)?
Are mangrove species-specific growth rates modified by changes in hydroperiod and along salinity gradients, and what physiological mechanisms are developed or optimized to maintain these growth rates?
How fast are productivity and nutrient flux patterns within mangrove forests reestablished after major human (e.g., fresh- water diversions) and natural (e.g., hurricanes) disturbances?
Does the relative importance of organic matter exported from mangrove forests as a major food source to sustain secondary production vary across geomorphological settings?
How do accretion and elevation rates in mangrove forests vary in response to change in sea-level rise across the Caribbean?
What is the minimum nutrient loading rate that triggers the replacement of sea grass–dominated systems with phytoplankton-dominated systems? Is the magnitude of this rate similar across different geomorphological settings?
How are the growth and reproduction rates of sea grass modified as nutrient availability increases? Are species- specific responses related to site-specific hydrological and salinity regimes?
What is the role of the interaction between sediment oxygen concentrations and nutrient availability in con- trolling the spatial distribution and mortality of sea grass?
How are the growth rate and spatial distribution of sea grass affected when mangrove forests are removed?
How fast do sea grasses recover after major natural (hurricanes) and human (nutrient enrichment) disturbances?
cultural, educational, and economic differ- ences among these countries. Of particular importance are the diverse management poli- cies (or complete lack thereof) that each coun- try has developed, based on economic priorities that do not embrace sustainable development.
One of the major priorities for sustain-
able management of the rich diversity of eco- systems in the wider Caribbean is to develop cost-effective research programs addressing common management issues in different
of coordinated support
locations. Cross-domain approaches and col-
among the 36 to 40 Caribbean nations and territories for mon- itoring the rich and diverse ecosystems in the region. Some of the major impediments to such coordination are the wide
laborations could foster the development of analytical and experimental tools to address common environmental prob- lems in the region. The approach and research agenda
September 2004 / Vol. 54 No. 9 • BioScience 853