Browsing by Subject "Florida"

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Open Access
Algal blooms and the nitrogen-enrichment hypothesis in Florida springs: evidence, alternatives, and adaptive management.
(Ecol Appl, 2010-04) Heffernan, James B; Liebowitz, Dina M; Frazer, Thomas K; Evans, Jason M; Cohen, Matthew J
Contradictions between system-specific evidence and broader paradigms to explain ecosystem behavior present a challenge for natural resource management. In Florida (U.S.A.) springs, increasing nitrate (NO3-) concentrations have been implicated as the cause of algal overgrowth via alleviation of N-limitation. As such, policy and management efforts have centered heavily on reduction of nitrogen (N) loads. While the N-limitation hypothesis appears well founded on broadly supported aquatic eutrophication models, several observations from Florida springs are inconsistent with this hypothesis in its present simplified form. First, NO3- concentration is not correlated with algal abundance across the broad population of springs and is weakly negatively correlated with primary productivity. Second, within individual spring runs, algal mats are largely confined to the headwater reaches within 250 m of spring vents, while elevated NO3- concentrations persist for several kilometers or more. Third, historic observations suggest that establishment of macroalgal mats often lags behind observed increases in NO3- by more than a decade. Fourth, although microcosm experiments indicate high thresholds for N-limitation of algae, experiments in situ have demonstrated only minimal response to N enrichment. These muted responses may reflect large nutrient fluxes in springs, which were sufficient to satisfy present demand even at historic concentrations. New analyses of existing data indicate that dissolved oxygen (DO) has declined dramatically in many Florida springs over the past 30 years, and that DO and grazer abundance are better predictors of algal abundance in springs than are nutrient concentrations. Although a precautionary N-reduction strategy for Florida springs is warranted given demonstrable effects of nutrient enrichment in a broad suite of aquatic systems worldwide, the DO-grazer hypothesis and other potential mechanisms merit increased scientific scrutiny. This case study illustrates the importance of an adaptive approach that explicitly evaluates paradigms as hypotheses and actively seeks alternative explanations.
Open Access
Challenges and Solutions to Permitting Living Shoreline Projects
(2024-11-01) Wetzler, Chloe; Mason, Sara; Olander, Lydia
Open Access
Coastal Community Resilience to Natural Hazards: A Socio-Economic Policy Analysis of Communities along the Florida Gulf Coast
(2012-04-26) Spiegler, Sarah; Lavey, Stephanie; Herrera, Daniel
This master’s project is the beginning of a 5-year investigative effort by Woods Hole Oceanographic Institution and Mote Marine Lab studying the harmful effects of red tides. This paper investigates the resilience of coastal communities in western Florida in the face of natural hazards. On Florida’s Gulf Coast, despite chronic exposure to natural hazards, coastal communities are growing in population and economic scale. Coastal development is often haphazard and unplanned, resulting in degradation of fragile and hazard-prone coastal ecosystems. This places communities at greater risk to the effects of coastal hazards. This paper hypothesizes that, although it is unlikely that natural disasters independently drive economic trends in this region, their presence exacerbates preexisting vulnerable economic conditions on an annual time-scale. This study investigates community resilience of Florida’s 23 Gulf Coast counties, exploring the adaptive capacity of the counties to absorb shocks while maintaining essential functions. Community resilience of western Florida is affected by the spatial and temporal distribution of hazard exposure. This paper assumes the effects of hazards are reflected in annual economic and population data for the year following the hazard. It categorizes historical storms and red tides and responses to these events via trends in four economic indicators for each county from 1969 to 2011; population, employment, per capita income, and number of proprietors. The results of this study show there were very few changes in the trends of the economic indicators after one year for most of the hazard events. The majority of economic and demographic data show persistent increases between 1969 and 2011, indicating that the Florida Gulf Coast system is resilient to red tides and hurricanes. Decreases in economic data trends were more closely correlated to years of economic recessions, not red tide blooms or major hurricanes years. This analysis suggests that storms and red tides may exacerbate decreases in economic and demographic data in the year following the storm, but that counties rebound to previous levels after one year. It concludes that perturbations from normal economic and population trends are most likely due to a combination of factors, such as economic recessions or anomalous air temperatures, along with natural hazards. It is also possible that effective government policies enhancing and protecting social and economic resilience can be addressed through public polices over time in response to hazard events, contributing to the increased resilience of coastal communities. Policies that plan, mitigate, and adapt to these hazards create a more resilient socio-economic system. Because the effects of these policies are not always immediately clear, resilience planning is difficult. Red tides and hurricanes place the growing population of Florida at greater risk for structural damage and economic downturns following hazard events. Increasing population in the Gulf Coast of Florida and the impending effects of climate change may decrease community resilience in the future. It is necessary for policymakers to consider these challenges and others inherent in resiliency planning. This paper concludes with a compilation of policy recommendations based on resilience research that state and local officials may consider for mitigating harmful effects of natural hazards.
Open Access
Discharge competence and pattern formation in peatlands: a meta-ecosystem model of the Everglades ridge-slough landscape.
(PLoS One, 2013) Heffernan, James B; Watts, Danielle L; Cohen, Matthew J
Regular landscape patterning arises from spatially-dependent feedbacks, and can undergo catastrophic loss in response to changing landscape drivers. The central Everglades (Florida, USA) historically exhibited regular, linear, flow-parallel orientation of high-elevation sawgrass ridges and low-elevation sloughs that has degraded due to hydrologic modification. In this study, we use a meta-ecosystem approach to model a mechanism for the establishment, persistence, and loss of this landscape. The discharge competence (or self-organizing canal) hypothesis assumes non-linear relationships between peat accretion and water depth, and describes flow-dependent feedbacks of microtopography on water depth. Closed-form model solutions demonstrate that 1) this mechanism can produce spontaneous divergence of local elevation; 2) divergent and homogenous states can exhibit global bi-stability; and 3) feedbacks that produce divergence act anisotropically. Thus, discharge competence and non-linear peat accretion dynamics may explain the establishment, persistence, and loss of landscape pattern, even in the absence of other spatial feedbacks. Our model provides specific, testable predictions that may allow discrimination between the self-organizing canal hypotheses and competing explanations. The potential for global bi-stability suggested by our model suggests that hydrologic restoration may not re-initiate spontaneous pattern establishment, particularly where distinct soil elevation modes have been lost. As a result, we recommend that management efforts should prioritize maintenance of historic hydroperiods in areas of conserved pattern over restoration of hydrologic regimes in degraded regions. This study illustrates the value of simple meta-ecosystem models for investigation of spatial processes.
Open Access
Diving Behavior of Female Loggerhead Turtles (Caretta caretta) During Their Internesting Interval and an Evaluation of the Risk of Boat Strikes
(2008-12-05T14:42:14Z) Sobin, Jacob
New advantages in science and technology, such as time depth recorders (TDRs), have allowed researchers to study the dive behavior of sea turtles in their natural habitats. Observing dive behavior of internesting turtles has provided significant evidence on how to protect nesting turtles from human interactions. One source of anthropogenic mortality on marine turtles is boat strikes. Trend data from the Florida Sea Turtle Stranding Network demonstrate that the annual proportions of boat-strike related mortality is increasing. Since 1980 boat strike injuries have tripled in Florida. This study, near Casey Key Beach in southwest Florida, examined the internesting dive behavior of loggerhead sea turtles using time-depth-recorders; National Geographic Crittercamstm, and satellite-linked location data to evaluate the risk of boat impacts based on the resulting dive data. When combined with 4 years of satellite telemetry data gathered prior to this study I revealed that loggerhead turtles are most vulnerable to boat strikes between 8 a.m. – 12 p.m. on the day following a nesting or false crawl event and on the night before returning to the beach to nest. Potential mitigation measures, such as spatial and temporal boat restrictions, are reviewed by this study.
Open Access
Equity and accuracy in medical malpractice insurance pricing.
(J Health Econ, 1990-11) Sloan, FA; Hassan, M
This study examines alternative classification approaches for setting medical malpractice insurance premiums. Insurers generally form risk classification categories on factors other than the physician's own loss experience. Our analysis of such classification approaches indicates different but no more categories than now used. An actuarially-fair premium-setting scheme based on the frequency and severity of the individual physician's losses would substantially penalize adverse experience. Alternatively, premiums could be set for groups of physicians, such as hospital medical staffs. Our simulations suggest that even staffs at rather small hospitals may be large enough to be experience-rated.
Open Access
Evaluation of Thermal Characteristics of Secondary Warm-Water Sites for the Florida Manatee
(2010-04-30T19:05:50Z) Loomis, Caroline Pitt
While the threat of collisions with recreational watercraft continues to be a serious concern for the Florida manatee population, a growing threat in the future is likely to be the loss of available winter habitat. Manatees are at risk of illness or death in water temperatures less than 20°C. To meet their thermoregulatory needs, manatees rely on sources of warm-water habitat. Currently the majority of the population is utilizing thermal discharges at coastal power plants to stay warm during winter cold periods; however, most of these power plants are expected to close down in the next t20 to 50 years. Since 1998 the Florida Fish and Wildlife Conservation Commission (FWC) has collected time-series temperature data at various sites used by manatees in winter. The goal of my project was to evaluate the thermal characteristics of 10 suspected warm-water sites in southern Florida to assess their potential suitability as winter habitat for manatees. Sites were assessed based on how frequently they were at temperatures considered threatening to manatee health and mortality, and on how many consecutive days they remained below these threshold temperatures. Delta-T and regression analysis were also used to compare the temperature of potential warm-water sites to that of nearby ambient sites. The results of this analysis will be used to make recommendations to the FWC about which sites might provide suitable warm-water habitat and should be further investigated with more detailed monitoring efforts in the future. This information could be used to meet the agency’s long-term goal of creating a protected network of warm-water habitat throughout the state.
Open Access
Evidence Library for Mangrove Degradation and Recovery
(2024-03-11) Mason, Sara; Mustafa, Madena; Dickson, Virginia; Griffin, Madison
Open Access
Restoring a River of Grass: Everglades policy recommendations for a climate change alternative
(2008-04-24T23:39:42Z) Krajewski, Jennifer
One of the largest and most extensive wetland systems in the United States is contained within the Florida Everglades National Park. Like most of the world’s wetlands it has been reduced to half of its size and heavily altered by human pressures. The Everglades were heavily drained during the first half of the 1800’s for agriculture and development. Further changes occurred after Congress authorized the Central and South Florida Project in 1948. Regrettably, the network of canals, levees, and roads created by the Central and South Florida Project greatly altered the water regime, starved the Everglades of its natural water flow, and compartmentalized the landscape. In an effort to reverse the impacts of earlier projects and to restore the natural hydropattern, Congress authorized the Comprehensive Everglades Restoration Plan (CERP) in 2000. However, future potential climate change impacts were not taken into consideration during the CERP planning process. The Everglades are extremely vulnerable to global climate change including: rising sea levels and sea surface temperatures, increased erosion, hurricane intensity and duration, saltwater intrusion and changes in precipitation. Therefore, it is important to consider Everglades’ restoration plans in light of global climate change. None of the restoration alternatives evaluated by CERP would be successful as a climate change alternative because global climate change predictions were not considered during the modeling and evaluation process. Failure to include future potential changes undermines any plan’s ability to restore the Everglades. This project investigates the potential climate change impacts for the Everglades National Park and provides policy recommendations regarding the inclusion of climate change predictions in the planning and implementation process. The three recommendations proposed include: the incorporation of current climate change predictions in the hydrologic and ecologic computer-based models, the monitoring and mapping of salinity levels within the Everglades National Park, and the use of the coastal vulnerability index to assess the vulnerability of the coastline of south Florida to future changes in sea level rise. The application of these recommendations will ensure the use of more appropriate models and techniques that will be better able to predict the success of planned restoration efforts.
Open Access
Shellfish aquaculture management priorities in Florida, Maine and North Carolina
(2024-04-25) Arthur, Maeve
The rapid expansion of the marine shellfish aquaculture industry in coastal U.S. states is characterized by environmental, social, and economic benefits as well as management challenges. To meet this growth, managers need to better understand what objectives to prioritize when managing the sector. This project explores how residents living in Florida, Maine, and North Carolina—three states characterized by emerging and ambitious shellfish aquaculture sectors—view the development and management of the industry. This project asks 1) which shellfish aquaculture management objectives are most important to residents and 2) does prioritization of management objectives vary among demographic and other predictor variables. A large-scale survey (n=1011) was deployed to respondents in the three study states and survey data were entered into SPSS to perform statistical analyses. Results show that the most important management objectives for respondents across all demographics are supporting local/coastal community economic development, safeguarding the natural environment, and maintaining coastal culture and heritage. These top three objectives represent economic, environmental, and social dimensions of aquaculture development, suggesting that residents want aquaculture to fulfill multiple goals. The results suggest four conclusions: 1) residents want aquaculture management and development to serve multiple needs within their communities, 2) residents think that benefits of shellfish aquaculture production should primarily be distributed to producing communities, 3) some predictor variables are more important for managers to consider while others are less so, and 4) managers may use a survey approach to understand how to prioritize a range of objectives, setting them up to effectively manage shellfish aquaculture growth in their locality.