29 resultados para grassland restoration
em Digital Commons at Florida International University
Resumo:
This dissertation examines the sociological process of conflict resolution and consensus building in South Florida Everglades Ecosystem Restoration through what I define as a Network Management Coordinative Interstitial Group (NetMIG). The process of conflict resolution can be summarized as the participation of interested and affected parties (stakeholders) in a forum of negotiation. I study the case of the Governor's Commission for a Sustainable South Florida (GCSSF) that was established to reduce social conflict. Such conflict originated from environmental disputes about the Everglades and was manifested in the form of gridlock among regulatory (government) agencies, Indian tribes, as well as agricultural, environmental conservationist and urban development interests. The purpose of the participatory forum is to reduce conflicts of interest and to achieve consensus, with the ultimate goal of restoration of the original Everglades ecosystem, while cultivating the economic and cultural bases of the communities in the area. Further, the forum aim to formulate consensus through envisioning a common sustainable community by providing means to achieve a balance between human and natural systems. ^ Data were gathered using participant observation and document analysis techniques to conduct a theoretically based analysis of the role of the Network Management Coordinative Interstitial Group (NetMIG). I use conflict resolution theory, environmental conflict theory, stakeholder analysis, systems theory, differentiation and social change theory, and strategic management and planning theory. ^ The purpose of this study is to substantiate the role of the Governor's Commission for a Sustainable South Florida (GCSSF) as a consortium of organizations in an effort to resolve conflict rather than an ethnographic study of this organization. Environmental restoration of the Everglades is a vehicle for recognizing the significance of a Network Management Coordinative Interstitial Group (NetMIG), namely the Governor's Commission for a Sustainable South Florida (GCSSF), as a structural mechanism for stakeholder participation in the process of social conflict resolution through the creation of new cultural paradigms for a sustainable community. ^
Resumo:
Periphyton communities dominate primary production in much of the Florida Everglades wetland and therefore contribute to soil production, ecosystem metabolism and secondary production as well as the composition of dependent communities. Decades of research in the Everglades have supported research findings from other wetland types that cumulatively show that periphyton communities respond very rapidly to alterations in the two dominant drivers of wetland structure and function—hydrology and water quality. Hydrology controls periphyton productivity and composition by regulating moisture availability, substrate types available for colonization and supply of nutrients. Nutrients, particularly the limiting nutrient in this system, phosphorus (P), control levels of production and community composition. Because periphyton communities are well-established to be related to hydrology and water quality, an indicator was developed based on three periphyton attributes: abundance, quality (i.e., nutrient content) and community composition. This assessment tool offers a qualitative assessment of ecosystem response to potential changes in management activities at a time scale appropriate for active management. An example is provided of how the indicator can be used to assess the current water quality and hydrological conditions from high-density spatial surveys. Detected patterns of deterioration align with expectations derived from model predictions and known sources of nutrients and unnatural hydrologic regimes. If employed adaptively in ecosystem management, this tool can be used to both detect and react to change before the system has been irreparably altered.
Resumo:
The pink shrimp, Farfantepenaeus duorarum, familiar to most Floridians as either food or bait shrimp, is ubiquitous in South Florida coastal and offshore waters and is proposed as an indicator for assessing restoration of South Florida's southern estuaries: Florida Bay, Biscayne Bay, and the mangrove estuaries of the lower southwest coast. Relationships between pink shrimp and salinity have been determined in both field and laboratory studies. Salinity is directly relevant to restoration because the salinity regimes of South Florida estuaries, critical nursery habitat for the pink shrimp, will be altered by changes in the quantity, timing, and distribution of freshwater inflow planned as part of the Comprehensive Everglades Restoration Project (CERP). Here we suggest performance measures based on pink shrimp density (number per square meter) in the estuaries and propose a restoration assessment and scoring scheme using these performance measures that can readily be communicated to managers, policy makers, and the interested public. The pink shrimp is an appropriate restoration indicator because of its ecological as well as its economic importance and also because scientific interest in pink shrimp in South Florida has produced a wealth of information about the species and relatively long time series of data on both juveniles in estuarine nursery habitats and adults on the fishing grounds. We suggest research needs for improving the pink shrimp performance measure.
Resumo:
We have developed a comprehensive ecological indicator for invasive exotic plants, a human-influenced component of the Everglades that could threaten the success of the restoration initiative. Following development of a conceptual ecological model for invasive exotic species, presented as a companion paper in this special issue, we developed criteria to evaluate existing invasive exotic monitoring programs for use in developing invasive exotic performance measures. We then used data from the selected monitoring programs to define specific performance measures, using species presence and abundance as the basis of the indicator for invasive exotic plants. We then developed a series of questions used to evaluate region and/or individual species status with respect to invasion. Finally, we used an expert panel who had answered the questions for invasive exotic plants in the Everglades Lake Okeechobee model to develop a stoplight restoration report card to communicate invasive exotic plant status. The report card system provides a way to effectively evaluate and present indicator data to managers, policy makers, and the public using a uniform format among indicators. Collectively, the model, monitoring assessment, performance measures, and report card enable us to evaluate how invasive plants are impacting the restoration program and how effectively that impact is being managed. Applied through time, our approach also allows us to follow the progress of management actions to control the spread and reduce the impacts of invasive species and can be easily applied and adapted to other large-scale ecosystem projects.
Resumo:
We developed a conceptual ecological model (CEM) for invasive species to help understand the role invasive exotics have in ecosystem ecology and their impacts on restoration activities. Our model, which can be applied to any invasive species, grew from the eco-regional conceptual models developed for Everglades restoration. These models identify ecological drivers, stressors, effects and attributes; we integrated the unique aspects of exotic species invasions and effects into this conceptual hierarchy. We used the model to help identify important aspects of invasion in the development of an invasive exotic plant ecological indicator, which is described a companion paper in this special issue journal. A key aspect of the CEM is that it is a general ecological model that can be tailored to specific cases and species, as the details of any invasion are unique to that invasive species. Our model encompasses the temporal and spatial changes that characterize invasion, identifying the general conditions that allow a species to become invasive in a de novo environment; it then enumerates the possible effects exotic species may have collectively and individually at varying scales and for different ecosystem properties, once a species becomes invasive. The model provides suites of characteristics and processes, as well as hypothesized causal relationships to consider when thinking about the effects or potential effects of an invasive exotic and how restoration efforts will affect these characteristics and processes. In order to illustrate how to use the model as a blueprint for applying a similar approach to other invasive species and ecosystems, we give two examples of using this conceptual model to evaluate the status of two south Florida invasive exotic plant species (melaleuca and Old World climbing fern) and consider potential impacts of these invasive species on restoration.
Resumo:
Developing scientifically credible tools for measuring the success of ecological restoration projects is a difficult and a non-trivial task. Yet, reliable measures of the general health and ecological integrity of ecosystems are critical for assessing the success of restoration programs. The South Florida Ecosystem Restoration Task Force (Task Force), which helps coordinate a multi-billion dollar multi-organizational effort between federal, state, local and tribal governments to restore the Florida Everglades, is using a small set of system-wide ecological indicators to assess the restoration efforts. A team of scientists and managers identified eleven ecological indicators from a field of several hundred through a selection process using 12 criteria to determine their applicability as part of a system-wide suite. The 12 criteria are: (1) is the indicator relevant to the ecosystem? (2) Does it respond to variability at a scale that makes it applicable to the entire system? (3) Is the indicator feasible to implement and is it measureable? (4) Is the indicator sensitive to system drivers and is it predictable? (5) Is the indicator interpretable in a common language? (6) Are there situations where an optimistic trend with regard to an indicator might suggest a pessimistic restoration trend? (7) Are there situations where a pessimistic trend with regard to an indicator may be unrelated to restoration activities? (8) Is the indicator scientifically defensible? (9) Can clear, measureable targets be established for the indicator to allow for assessments of success? (10) Does the indicator have specificity to be able to result in corrective action? (11) What level of ecosystem process or structure does the indicator address? (12) Does the indicator provide early warning signs of ecological change? In addition, a two page stoplight report card was developed to assist in communicating the complex science inherent in ecological indicators in a common language for resource managers, policy makers and the public. The report card employs a universally understood stoplight symbol that uses green to indicate that targets are being met, yellow to indicate that targets have not been met and corrective action may be needed and red to represent that targets are far from being met and corrective action is required. This paper presents the scientific process and the results of the development and selection of the criteria, the indicators and the stoplight report card format and content. The detailed process and results for the individual indicators are presented in companion papers in this special issue of Ecological Indicators.
Resumo:
In south Florida, tropical hardwood forests (hammocks) occur in Everglades tree islands and as more extensive forests in coastal settings in the nearby Florida Keys. Keys hammocks have been less disturbed by humans, and many qualify as “old-growth,” while Everglades hammocks have received much heavier use. With improvement of tree island condition an important element in Everglades restoration efforts, we examined stand structure in 23 Keys hammocks and 69 Everglades tree islands. Based on Stand Density Index and tree diameter distributions, many Everglades hammocks were characterized by low stocking and under-representation in the smaller size classes. In contrast, most Keys forests had the dense canopies and open understories usually associated with old-growth hardwood hammocks. Subject to the same caveats that apply to off-site references elsewhere, structural information from mature Keys hammocks can be helpful in planning and implementing forest restoration in Everglades tree islands. In many of these islands, such restoration might involve supplementing tree stocking by planting native trees to produce more complete site utilization and a more open understory.
Resumo:
Historic changes in water-use management in the Florida Everglades have caused the quantity of freshwater inflow to Florida Bay to decline by approximately 60% while altering its timing and spatial distribution. Two consequences have been (1) increased salinity throughout the bay, including occurrences of hypersalinity, coupled with a decrease in salinity variability, and (2) change in benthic habitat structure. Restoration goals have been proposed to return the salinity climates (salinity and its variability) of Florida Bay to more estuarine conditions through changes in upstream water management, thereby returning seagrass species cover to a more historic state. To assess the potential for meeting those goals, we used two modeling approaches and long-term monitoring data. First, we applied the hydrological mass balance model FATHOM to predict salinity climate changes in sub-basins throughout the bay in response to a broad range of freshwater inflow from the Everglades. Second, because seagrass species exhibit different sensitivities to salinity climates, we used the FATHOM-modeled salinity climates as input to a statistical discriminant function model that associates eight seagrass community types with water quality variables including salinity, salinity variability, total organic carbon, total phosphorus, nitrate, and ammonium, as well as sediment depth and light reaching the benthos. Salinity climates in the western sub-basins bordering the Gulf of Mexico were insensitive to even the largest (5-fold) modeled increases in freshwater inflow. However, the north, northeastern, and eastern sub-basins were highly sensitive to freshwater inflow and responded to comparatively small increases with decreased salinity and increased salinity variability. The discriminant function model predicted increased occurrences ofHalodule wrightii communities and decreased occurrences of Thalassia testudinum communities in response to the more estuarine salinity climates. The shift in community composition represents a return to the historically observed state and suggests that restoration goals for Florida Bay can be achieved through restoration of freshwater inflow from the Everglades.
Resumo:
Large numbers of colonially nesting herons, egrets, ibises, storks and spoonbills were one of the defining natural phenomena of the historical Everglades. Reproduction of these species has been tracked over at least a century, and some clear responses to dramatic anthropogenic hydrological alterations have been established. These include a marked decline in nesting populations of several species, and a movement of colonies away from the over-drained estuarine region. Ponding in a large portion of the freshwater marsh has favored species that hunt by sight in deep water (egrets, cf. 25–45 cm), while tactile feeders (ibises and storks) that depend on concentrated prey in shallow water (5–25 cm) have become proportionately much less common. There has been a marked increase in the interval between exceptionally large breeding aggregations of White Ibises (Eudocimus albus). Loss of short hydroperiod wetlands on the margins of the Everglades have delayed nest initiations 1–2 months by Wood Storks (Mycteria americana) resulting in poor nesting success. These responses are consistent with mechanisms that involve foraging, and the availability and production of prey animals, and each of the relationships is highly dependent on hydrology. Here, we define a group of characteristics about wading bird dynamics (= indicators) that collectively track the specific ecological relationships that supported ibises and storks in the past. We suggest four metrics as indicators of restoration success: timing of nesting by storks, the ratio of nesting ibises + storks to Great Egrets, the proportion of all nests located in the estuarine/freshwater ecotone, and the interval between years with exceptionally large ibis nestings. Each of these metrics has historical (e.g., predrainage) data upon which to base expectations for restoration, and the metrics have little measurement error relative to the large annual variation in numbers of nests. In addition to the strong scientific basis for the use of these indicators, wading birds are also a powerful tool for public communication because they have strong aesthetic appeal, and their ecological relationships with water are intuitively understandable. In the interests of communicating with the public and decision-makers, we integrate these metrics into a single-page annual “traffic-light” report card for wading bird responses. Collectively, we believe these metrics offer an excellent chance of detecting restoration of the ecosystem functions that supported historical wading bird nesting patterns.
Resumo:
Lake Okeechobee, Florida, located in the middle of the larger Kissimmee River-Lake Okeechobee-Everglades ecosystem in South Florida, serves a variety of ecosystem and water management functions including fish and wildlife habitat, flood control, water supply, and source water for environmental restoration. As a result, the ecological status of Lake Okeechobee plays a significant role in defining the overall success of the greater Everglades ecosystem restoration initiative. One of the major ecological indicators of Lake Okeechobee condition focuses on the near-shore and littoral zone regions as characterized by the distribution and abundance of submerged aquatic vegetation (SAV) and giant bulrush (Scirpus californicus(C.A. Mey.) Steud.). The objective of this study is to present a stoplight restoration report card communication system, common to all 11 indicators noted in this special journal issue, as a means to convey the status of SAV and bulrush in Lake Okeechobee. The report card could be used by managers, policy makers, scientists and the public to effectively evaluate and distill information about the ecological status in South Florida. Our assessment of the areal distribution of SAV in Lake Okeechobee is based on a combination of empirical SAV monitoring and output from a SAV habitat suitability model. Bulrush status in the lake is related to a suitability index linked to adult survival and seedling establishment metrics. Overall, presentation of these performance metrics in a stoplight format enables an evaluation of how the status of two major components of Lake Okeechobee relates to the South Florida restoration program, and how the status of the lake influences restoration efforts in South Florida.
Resumo:
The Everglades freshwater marl prairie is a dynamic and spatially heterogeneous landscape, containing thousands of tree islands nested within a marsh matrix. Spatial processes underlie population and community dynamics across the mosaic, especially the balance between woody and graminoid components, and landscape patterns reflect interactions among multiple biotic and abiotic drivers. To better understand these complex, multi-scaled relationships we employed a three-tiered hierarchical design to investigate the effects of seed source, hydrology, and more indirectly fire on the establishment of new woody recruits in the marsh, and to assess current tree island patterning across the landscape. Our analyses were conducted at the ground level at two scales, which we term the micro- and meso-scapes, and results were related to remotely detected tree island distributions assessed in the broader landscape, that is, the macro-scape. Seed source and hydrologic effects on recruitment in the micro- and meso-scapes were analyzed via logistic regression, and spatial aggregation in the macro-scape was evaluated using a grid-based univariate O-ring function. Results varied among regions and scales but several general trends were observed. The patterning of adult populations was the strongest driver of recruitment in the micro- and meso-scape prairies, with recruits frequently aggregating around adults or tree islands. However in the macro-scape biologically associated (second order) aggregation was rare, suggesting that emergent woody patches are heavily controlled by underlying physical and environmental factors such as topography, hydrology, and fire.
Resumo:
Recent research makes clear that much of the Everglade’s flora and fauna have evolved to tolerate or require frequent fires. Nevertheless, restoration of the Everglades has thus far been conceptualized as primarily a water reallocation project. These two forces are directly linked by the influence of water flows on fire fuel moisture content, and are indirectly linked through a series of complex feedback loops. This interaction is made more complex by the alteration and compartmentalization of current water flows and fire regimes, the lack of communication between water and fire management agencies, and the already imperiled state of many local species. It is unlikely, therefore, that restoring water flows will automatically restore the appropriate fire regimes, leaving the prospect of successful restoration in some doubt. The decline of the Cape Sable seaside sparrow, and its potential for recovery, illustrates the complexity of the situation.
Resumo:
During the 1960s, water management practices resulted in the conversion of the wetlands that fringe northeastern Florida Bay (USA) from freshwater/oligohaline herbaceous marshes to dwarf red mangrove forests. Coincident with this conversion were several ecological changes to Florida Bay’s fauna, including reductions in the abundances of top trophic-level consumers: piscivorous fishes, alligators, crocodiles, and wading birds. Because these taxa rely on a common forage base of small demersal fishes, food stress has been implicated as playing a role in their respective declines. In the present study, we monitored the demersal fishes seasonally at six sites over an 8-year time period. During monitoring, extremely high rainfall conditions occurred over a 3.5-year period leading to salinity regimes that can be viewed as “windows” to the area’s natural past and future restored states. In this paper, we: (1) examine the changes in fish communities over the 8-year study period and relate them to measured changes in salinity; (2) make comparisons among marine, brackish and freshwater demersal fish communities in terms of species composition, density, and biomass; and (3) discuss several implications of our findings in light of the intended and unintended water management changes that are planned or underway as part of Everglades restoration. Results suggest the reduction in freshwater flow to Florida Bay over the last several decades has reduced demersal fish populations, and thus prey availability for apex consumers in the coastal wetlands compared to the pre-drainage inferred standard. Furthermore, greater discharge of freshwater toward Florida Bay may result in the re-establishment of pre-1960s fauna, including a more robust demersal-fish community that should prompt increases in populations of several important predatory species.
Resumo:
Alligators and crocodiles integrate biological impacts of hydrological operations, affecting them at all life stages through three key aspects of Everglades ecology: (1) food webs, (2) diversity and productivity, and (3) freshwater flow. Responses of crocodilians are directly related to suitability of environmental conditions and hydrologic change. Correlations between biological responses and environmental conditions contribute to an understanding of species’ status and trends over time. Positive or negative trends of crocodilian populations relative to hydrologic changes permit assessment of positive or negative trends in restoration. The crocodilian indicator uses monitoring parameters (performance measures) that have been shown to be both effective and efficient in tracking trends. The alligator component uses relative density (reported as an encounter rate), body condition, and occupancy rates of alligator holes; the crocodile component uses juvenile growth and hatchling survival. We hypothesize that these parameters are correlated with hydrologic conditions including depth, duration, timing, spatial extent and water quality. Salinity is a critical parameter in estuarine habitats. Assessments of parameters defined for crocodilian performance measures support these hypotheses. Alligators and crocodiles are the charismatic megafauna of the Everglades. They are both keystone and flagship species to which the public can relate. In addition, the parameters used to track trends are easy to understand. They provide answers to the following questions: How has the number of alligators or crocodiles changed? Are the animals fatter or thinner than they should be? Are the animals in the places (in terms of habitat and geography) where they should be? As surely as there is no other Everglades, no other single species defines the Everglades as does the American alligator. The Everglades is the only place in the world where both alligators and crocodiles exist. Crocodilians clearly respond to changes in hydrologic parameters of management interest. These relationships are easy to communicate and mean something to managers, decision makers, and the public. Having crocodilians on the list of system-wide, general indicators provides us with one of the most powerful tools we have to communicate progress of ecosystem restoration in Greater Everglades ecosystems to diverse audiences.
Resumo:
Ecological monitoring is key to successful ecosystem restoration. Because all components within an ecosystem cannot be monitored, it is important to select indicators that are representative of the system, integrate system responses, clearly respond to system change, can be effectively and efficiently monitored, and are easily communicated. The roseate spoonbill is one ecological indicator species that meets these criteria within the Everglades ecosystem. Monitoring of roseate spoonbills in Florida Bay over the past 70 years has shown that aspects of this species’ reproduction respond to changes in hydrology and corresponding changes in prey abundance and availability. This indicator uses nesting location, nest numbers and nesting success in response to food abundance and availability. In turn, prey abundance is a function of hydrological conditions (especially water depth) and salinity. Metrics and targets for these performance measures were established based on previous findings. Values of each metric were translated into indices and identified as stoplight colors with green indicating that a given target has been met, yellow indicating that conditions are below the target, but within an acceptable range of it, and red indicating the measure is performing poorly in relation to the target.