Geology topics

Research about Florida

Source-linked reports with geographic coverage including Florida.

At least 361 records · Page 20Linked to original sources

USGS2019

Seeking shelter from the storm: Conservation and management of imperiled species in a changing climate

Climate change is anticipated to exacerbate the extinction risk of species whose persistence is already compromised by habitat loss, invasive species, disease, or other stressors. In coastal areas of the southeastern United States (USA), many imperiled vertebrates are vulnerable to hurricanes, which climate models predict to become more severe in the 21st century. Despite this escalating threat, explicit adaptation strategies that address hurricane threats, in particular, and climate change more generally, are largely underrepresented in recovery planning and implementation. We provide a basis for stronger emphasis on strategic planning for imperiled species facing the increasing threat of catastrophic hurricanes. Our reasoning comes from observations of short‐term environmental and biological impacts of Hurricane Michael, which impacted the Gulf Coast of the southeastern USA in October 2018. During this storm, St. Marks National Wildlife Refuge, located along the northern Gulf of Mexico's coast in the panhandle region of Florida, received storm surge that was 3.0–3.6 m (NAVD88) above sea level. Storm surge pushed sea water into some ephemeral freshwater ponds used for breeding by the federally threatened frosted flatwoods salamander ( Ambystoma cingulatum ). After the storm, specific conductance across all ponds measured varied from 80 to 23,100 µS/cm, compared to 75 to 445 µS/cm in spring 2018. For 17 overwashed wetlands that were measured in both spring and fall 2018, posthurricane conductance observations were, on average, more than 90 times higher than in the previous spring, setting the stage for varying population responses across this coastal landscape. Importantly, we found live individual flatwoods salamanders at both overwashed and non‐overwashed sites, although we cannot yet assess the demographic consequences of this storm. We outline actions that could be incorporated into climate adaptation strategies and recovery planning for imperiled species, like A. cingulatum , that are associated with freshwater coastal wetlands in hurricane‐prone regions.

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USGS2019

Impacts of saltwater intrusion on wetland prey production and composition in a historically freshwater marsh

Sea level rise is a fundamental driver of ecosystem change and has the potential to shift the spatial distributions of habitats more rapidly than species can adapt. Rapid sea level rise and associated saltwater intrusion have negative impacts on coastal environments, including loss of habitat for species such as sea turtles and shorebirds. In Florida’s largest wetland, the Everglades, the availability of small fishes that are prey for wading birds serve as an indicator of ecosystem health. In the southwestern part of the ecosystem, sea level rise and a reduction in freshwater flow have converted formerly freshwater marsh into an estuarine mangrove-dominated landscape. In this study, we sampled fish communities in this southwest portion of the Everglades exposed to a range of saline conditions. Biomass of native fishes was highest at a salinity value of approximately 25 parts per thousand, while non-native biomass decreased with increasing salinity. Applying salinity change scenarios, we determined that a 10% reduction from the salinity levels recorded in this study would be optimal for biomass of native fishes. The baseline data we collected on non-native fishes at the site will be useful for monitoring as restoration progresses and for managers working on invasive species control. This region has been actively undergoing ecosystem restoration for the last decade, but restored freshwater flow closer to historical conditions is still years away. Without increased freshwater inflow from hydrologic restoration, rising sea levels and saltwater intrusion may provide conservation challenges for wading birds and their prey-base fishes.

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USGS2019

Modeling the morphological response of a barrier island to Hurricane Matthew

Surge and wave forcing from Hurricane Matthew caused a breach south of Matanzas Inlet (FL, USA) on a complex barrier island, including sandy dunes, hard structures (residential buildings and a highway), wetlands, and the US Intracoastal Waterway. In this paper, the skill of the XBeach model to predict hurricane-induced barrier island overwash, dune erosion, and breaching is demonstrated. The location of the breach is predicted correctly if bottom roughness based on land cover is used to calculate bed shear stresses. While the dunes are initially lowered by wave attack and surge from the ocean side, the main driver for breach formation is the water level difference between the back-barrier and nearshore, causing an ocean-directed outflow of water after the peak of the storm.

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USGS2019

A federal-state partnership for mapping Florida's coast and seafloor

The Florida Coastal Mapping Program, a partnership of state and federal agencies, has a goal of having modern, consistent, high- resolution sea-floor data for all of Florida’s coastal zone in the next decade to support a myriad of coastal zone science and management applications. One of the early steps in the implementation process is to prioritize and justify mapping needs. This is accomplished by holding six regional workshops across the state during which stakeholders and partners are introduced to a newly developed geospatial prioritization tool. Users independently utilize the tool to populate grid cells for a given region, and the result is a cumulative perspective on sea floor mapping priorities to inform future mapping initiatives. The tool also allows participants to indicate their primary use of sea floor mapping data and types of additional data required for their science or management need.

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USGS2019

Daily to decadal variability of beach morphology at NASA-Kennedy Space Center: Storm influences across timescales

Shoreline variability over timescales ranging from days to decades is examined at NASA-Kennedy Space Center on the Atlantic coast of Florida. Three sources of shoreline position data are utilized to complete this analysis: hourly video-image observations, monthly Real Time Kinematic GPS observations, and historical aerial imagery dating back to 1943. We find that shoreline positions tend to respond coherently to monthly variations in wave energy, except during storm-driven shoreline change. A seasonal signal in shoreline behavior is also evident, however this signal becomes indiscernible after a rapid change in morphologic behavior following Hurricane Sandy’s impact in October 2012. Further, the spatial pattern of shoreline change following Sandy’s impact mimics decadal-scale trends, suggesting that response to large storms may be controlling decadal shoreline change behavior at this site.

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USGS2019

Improving estimates of coral reef construction and erosion with in-situ measurements

The decline in living coral since the 1970s has conspicuously slowed reef construction on a global scale, but the related process of reef erosion is less visible and not often quantified. Here we present new data on the constructional and deconstructional side of the carbonate-budget equation in the Florida Keys, U.S.A. We documented Orbicella spp. calcification rates at four offshore reefs and quantified decadal-scale rates of Orbicella-reef erosion at a mid-shore patch reef. Using Orbicella coral heads fitted with permanent markers in 1998, we measured reef-elevation loss at 28 stations over 17.3 years to estimate a mean erosion rate of -5.5 (± 3.2, SD) mm yr-1. This loss equates to an erosion rate of -8.2 (± 4.8, SD) kg m-2 yr-1 on dead Orbicella colonies, or -6.6 kg m-2 yr-1 when adjusted reef-wide. Calculating net carbonate production using a census-based approach on the same patch reef in 2017, we estimated a reef-wide bioerosion rate of -1.9 (± 2.0, SD) kg m-2 yr-1, and a net carbonate production rate of 0.5 (± 0.3, SD) kg m-2 yr-1. Substituting the erosion rate we estimated with the markers would suggest that net carbonate production at this patch reef was lower and negative, -4.2 kg m-2 yr-1. This divergence could be a function of high erosion rates measured on the tops of Orbicella colonies, which may be preferentially targeted by parrotfish. Nonetheless, our study suggests the need for new field data to improve estimates of reef-structure persistence as coral reefs continue to degrade.

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USGS2019

Environmental DNA sampling reveals high occupancy rates of invasive Burmese pythons at wading bird breeding aggregations in the central Everglades

The Burmese python ( Python bivittatus ) is now established as a breeding population throughout south Florida, USA. However, the extent of the invasion, and the ecological impacts of this novel apex predator on animal communities are incompletely known, in large part because Burmese pythons (hereafter “pythons”) are extremely cryptic and there has been no efficient way to detect them. Pythons are recently confirmed nest predators of long-legged wading bird breeding colonies (orders Ciconiiformes and Pelecaniformes). Pythons can consume large quantities of prey and may not be recognized as predators by wading birds, therefore they could be a particular threat to colonies. To quantify python occupancy rates at tree islands where wading birds breed, we utilized environmental DNA (eDNA) analysis—a genetic tool which detects shed DNA in water samples and provides high detection probabilities. We fitted multi-scale Bayesian occupancy models to test the prediction that pythons occupy islands with wading bird colonies at higher rates compared to representative control islands containing no breeding birds. Our results suggest that pythons are widely distributed across the central Everglades in proximity to active wading bird colonies. In support of our prediction that pythons are attracted to colonies, site-level python eDNA occupancy rates were higher at wading bird colonies (ψ = 0.88, 95% credible interval [0.59–1.00]) than at the control islands (ψ = 0.42 [0.16–0.80]) in April through June (n = 15 colony-control pairs). We found our water temperature proxy (time of day) to be informative of detection probability, in accordance with other studies demonstrating an effect of temperature on eDNA degradation in occupied samples. Individual sample concentrations ranged from 0.26 to 38.29 copies/μL and we generally detected higher concentrations of python eDNA in colony sites. Continued monitoring of wading bird colonies is warranted to determine the effect pythons are having on populations and investigate putative management activities.

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USGS2019

The effects of geography, habitat, and humans on the ecology and demography of the Gopher tortoise ( Gopherus polyphemus ) in the southern Lake Wales Ridge region of Florida

A 35-year (1967–2002) demographic study was conducted on the gopher tortoise (Gopherus polyphemus) from two different habitats on Archbold Biological Station located on the southern end of the Lake Wales Ridge in south-central Florida. We found geographic, habitat, and human-mediated effects on several aspects of its biology. Our findings underscore the necessity of long-term demographic data to more accurately answer ecological questions concerning long-lived species, such as how the gopher tortoise detectably might be affected by habitat quality and human activities.

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USGS2019

Tampa Bay Ocean and Coastal Acidification Monitoring Quality Assurance Project Plan

Coastal acidification caused by eutrophication, freshwater inflow, and upwelling is already affecting many estuaries worldwide and can be exacerbated by ocean acidification that is caused by increasing carbon dioxide in the atmosphere. Effective management, mitigation, and (or) adaptation to the effects of coastal and ocean acidification require careful monitoring of the resulting changes in seawater chemistry. Local, regional, and national agencies and institutions organizing acidification-monitoring and research efforts work toward standardizing data collection and reporting protocols so that data can be shared and compared across regions and synthesized into national assessments. This document describes a Quality Assurance Project Plan for the collection and reporting of seawater chemical and physical data using standardized methods and published best practices relevant for monitoring coastal and ocean acidification. The plan specifically addresses procedures for a joint partnership, the Tampa Bay Ocean and Coastal Acidification Monitoring project, conducted by the U.S. Geological Survey, the U.S. Environmental Protection Agency, and the Tampa Bay Estuary Program in the Tampa Bay estuary, Florida. The plan describes recommended procedures for project organization, sampling process design and methods, data-quality objectives and criteria, data validation and management procedures, and project deliverables.

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USGS2019

Florida Coastal Mapping Program—Overview and 2018 workshop report

The Florida Coastal Mapping Program is a nascent but highly relevant program that has the potential to greatly enhance the “Blue Economy” of Florida by coordinating and facilitating sea-floor mapping efforts and aligning partner and stakeholder activities for increased efficiency and cost reduction. Sustained acquisition of modern coastal mapping information for Florida may improve management of resources and reduce costs by eliminating redundancy. Economic growth could be aided by improved data to support emerging sectors such as aquaculture and renewable energy. The present focus of the Florida Coastal Mapping Program is on modern, high-resolution bathymetric and coastal topobathymetric data, which can be immediately used to update navigational charts and identify navigation hazards, provide fundamental baseline data for scientific research, and provide information for use by emergency managers and responders. Derivative products include identifying sand resources for beach nourishment, creating vastly improved models for coastal erosion and flooding, identifying coastal springs, and creating benthic habitat maps. The uses and applications of the data generated could grow over time. The process of creating a steering committee and technical team, conducting an inventory and gaps analysis, soliciting feedback from the stakeholder and partner communities, and developing a prioritization process has provided a framework on which a successful program can develop a sustainable funding strategy that may be an investment the citizens of Florida could benefit from for decades.

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USGS2019

Spatially distributed denitrification in a karst springshed

Karst spring measurements assess biogeochemical processes occurring within groundwater contributing areas to springs (springsheds) but can only provide aggregated information. To better understand spatially distributed processes that comprise these aggregated measures, we investigated aquifer denitrification evidence in groundwater wells ( n = 16) distributed throughout a springshed in the Upper Floridan aquifer in northern Florida. Aquifer geochemistry, nitrate isotopes, and dissolved gases were compared against similar measurements at the spring outlet to evaluate spatial heterogeneity of denitrification evidence in relation to land surface–aquifer connectivity. Sample locations spanned spatial variation in recharge processes (i.e., diffuse vs. focused recharge) and proximity to sources of denitrification reactants (e.g., wetlands). Although no distinct spatial pattern in denitrification was uncovered, excess dissolved N 2 gas measurements were only above detection in the unconfined springshed, with some evidence of a wetland proximity effect. Measured oxidation–reduction potential and dissolved oxygen poorly predicted denitrification, indicating that measured denitrification may be occurring upgradient from sampled wells. Despite dramatic spatial chemical heterogeneity across wells, mean values for recharge nitrate concentrations (0.02 to 5.56 mg N L −1 ) and excess N 2 from aquifer denitrification (below detection to 1.37 mg N L −1 ) corresponded reasonably with mean spring outlet measurements for initial nitrate (0.78 to 1.36 mg N L −1 ) and excess N 2 (0.15 to 1.04 mg N L −1 ). Congruence between groundwater and spring measurements indicates that combining sampling at the spring outlet and across the springshed is useful for understanding spatial aquifer denitrification. However, this approach would be improved with a high‐density sampling network with transects of wells along distinct groundwater flow paths.

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USGS2019

Potential for increased inundation in flood-prone regions of southeast Florida in response to climate and sea-level changes in Broward County, Florida, 2060–69

The U.S. Geological Survey, in cooperation with Broward County Environmental Planning and Resilience Division, has developed county-scale and local-scale groundwater/surface-water models to study the potential for increased inundation and flooding in eastern Broward County that are due to changes in future climate and sea-level rise. These models were constructed by using MODFLOW 2005, with the surface-water system represented by using the Surface-Water Routing process and a new Urban Runoff process. The local-scale model allowed the use of finer grid resolution in a selected area of the county, whereas the county-scale model provided boundary conditions for the local-scale model and insight into the hydrologic behavior of the larger system. The aquifer layering, properties, and boundaries relied heavily on a previous three-dimensional variable-density solute-transport model of the same area developed by the U.S. Geological Survey. The surface-water system within these new models actively simulates a part of the extensive canal network by using level-pool routing and active structure operations within the Surface-Water Routing process. These models were used to simulate a historical base-case period (1990–99) by using measured data and regional climate model rainfall and potential evapotranspiration output. The simulated flow and water-level results generally captured the behavior of the hydrologic system. A future period (2060–69) was simulated by using regional climate model rainfall and potential evapotranspiration output representing a wetter and drier future and low, intermediate, and high sea-level rise projections. The results were used to evaluate the potential effects on the surface-water drainage system, coastal-structure operation, and wet-season groundwater levels. Future period simulations using the county-scale model indicate that (1) the effects of the changing climate and sea level are much more evident in eastern and coastal areas of Broward County compared to western areas, with increases in groundwater level nearly equivalent to sea-level rise; (2) coastal groundwater-level increases are distributed farther inland in the wetter future scenarios than in the drier future scenarios; (3) water levels at the westernmost groundwater station locations exhibited little change caused by sea-level rise and showed more dependence on changes in precipitation; (4) there was a reduced west-to-east groundwater gradient with increasing sea-level rise; and (5) increased downstream tidal stage at the S–13 structure resulted in increased reliance on the pump to control upstream inland canal stages. Future simulations using the local-scale model indicate similar behavior as seen in the county-scale model: (1) the coastal areas exhibited the largest impacts in groundwater levels in the future scenarios; (2) the westernmost, interior areas exhibited little change during the future scenarios; and (3) there was an increased reliance on the pump at the S–13 coastal structure but to a lesser extent than indicated in the county-scale model because of the reduced temporal scale of the local-scale model. Possible adaptation and mitigation strategies were simulated to evaluate the county-scale and local-scale models’ ability to simulate hydrologic changes. Alterations to S–13 pump operations within the county-scale model were tested, and results indicate a reduced effect of sea-level rise inland of the control structure, but the affected area is spatially limited. The concept of using pumps to reduce the local groundwater levels in two neighborhood-sized areas was tested by using the local-scale model. The MODFLOW 2005 Drain package was used to remove groundwater by using drainage elevations set to zero, 1 foot, and 2 feet above average wet-season groundwater levels. Area 1 was well connected to coastal boundaries, and a high rate of groundwater removal was required, whereas the rate of groundwater removal required was greatly reduced in Area 2, which is less connected to tidal boundaries. Water for these scenarios was assumed to be pumped to tide with no downstream effects.

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USGS2019

Towards recovery of an endangered island endemic: Distributional and behavioral responses of Key Largo woodrats associated with exotic predator removal

Exotic predators create novel ecological contexts for native species, particularly when prey exhibit predator naïve behaviors. Population recovery of island endemic species following predator eradication has been documented broadly, but studies examining mammalian prey behavioral responses to exotic predator removal are less common. The Key Largo woodrat ( Neotoma floridana smalli ) is an endangered Florida endemic species that exhibited drastic declines, signified by the loss of natural stick-nests, over the past three decades due to habitat loss and effects from exotic predators. We conducted camera trap surveys of woodrats at supplemental nests and used dynamic multistate occupancy models to evaluate changes in woodrat distribution and stick-nest building behavior over a two-year period of exotic predator (domestic cats [ Felis catus ] and Burmese pythons [ Python bivittatus ]) removal. The distribution of woodrats using supplemental nests increased from 27% to 39% in the two-year period, while the proportion of occupied supplemental nests with stick-nests increased from 37% in 2013 to 54% in 2015. The probabilities of supplemental nest use and stick-nest building behavior increased over time following a gradient away from the northern extent of Key Largo, an area associated with high cat activity and the only sites of python captures during the surveys. Woodrats that built stick-nests were more detectable than those that did not, which suggests that stick-nest building could make woodrats more susceptible to predation from novel predators when performing the behavior. We documented increasing woodrat occurrence, along with increasing stick-nest building behavior, which supports recovery and management objectives focused on exotic predator removal.

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USGS2019

Efficacy of eDNA as an early detection indicator for Burmese pythons in the ARM Loxahatchee National Wildlife Refuge in the Greater Everglades Ecosystem

Environmental DNA (eDNA) detection of invasive species can be used to delimited occupied ranges and estimate probabilities to inform management decisions. Environmental DNA is shed into the environment through skin cells and bodily fluids and can be detected in water samples collected from lakes, rivers, and swamps. In south Florida, invasive Burmese pythons occupy much of the Greater Everglades in mostly inaccessible habitat and are credited with causing severe declines of native species’ populations. Detection of Burmese pythons by traditional methods, such as trapping and visual searching, have been largely ineffective, making eDNA a superior method for differentiating invaded habitat. We adapted a quantitative PCR eDNA assay for droplet digital PCR, a state-of-the-art method that improves precision and accuracy. From August 2014 to October 2016, locations in and around Arthur R. Marshall Loxahatchee National Wildlife Refuge in southeast Florida were surveyed for Burmese python eDNA. The Refuge is maintained to provide water storage and is considered one of the last remnants of the northern Everglades wetlands. Positive eDNA detections were made at each of the five sampling events, assessing a total of 399 samples, with moderate occurrence (ψ=58-91%) and detection (p=40-70%) probabilities, potentially reduced by high PCR inhibition-levels. The high occurrence rates and geographic distribution of the positive samples within the Refuge suggests a steady release of python eDNA from a resident Burmese python population and reduces support for primarily transport of eDNA through boats or flowing water from the north. The first confirmed sighting of a Burmese python in the Refuge occurred in September 2016, after eDNA testing had indicated the presence of pythons. An established population is not expected this far north, however, the detections likely indicate northern range limit of a consistent population at Loxahatchee on the eastern side of the Florida peninsula. Our study demonstrates the benefit of eDNA for determining more accurate range limits and expansion information for Burmese pythons, as well as laying the foundation for the assessment of control efforts.

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USGS2019

Influence of salinity on relative density of American crocodiles (Crocodylus acutus) in Everglades National Park: Implications for restoration of Everglades ecosystems

The status of the American crocodile (Crocodylus acutus) has long been a matter of concern in Everglades National Park (ENP) due to its classification as a federal and state listed species, its recognition as a flagship species, and its function as an ecosystem indicator. Survival and recovery of American crocodiles has been linked with regional hydrological conditions, especially freshwater flow to estuaries, which affect water levels and salinities. We hypothesize that efforts to restore natural function to Everglades ecosystems by improving water delivery into estuaries within ENP will change salinities and water levels which in turn will affect relative density of crocodiles. Monitoring ecological responses of indicator species, such as crocodiles, with respect to hydrologic change is necessary to evaluate ecosystem responses to restoration projects. Our objectives were to monitor trends in crocodile relative density within ENP and to determine influences of salinity on relative density of crocodiles. We examined count data from 12 years of crocodile spotlight surveys in ENP (2004 to 2015) and used a hierarchical model of relative density that estimated relative density with probability of detection. The mean predicted value for relative density (λ) across all surveys was 2.9 individuals/km (95% CI: 2.0 – 4.2); relative density was estimated to decrease with increases in salinity. Routes in ENP’s Flamingo/Cape Sable area had greater crocodile relative density than routes in the West Lake/Cuthbert Lake area and Northeast Florida Bay areas. These results are consistent with the hypothesis that restored flow and lower salinities will result in an increase in crocodile population size and provide support for the ecosystem management recommendations for crocodiles, which currently are to restore more natural patterns of freshwater flow to Florida Bay. Thus, monitoring relative density of American crocodiles will continue to be an effective indicator of ecological response to ecosystem restoration.

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USGS2019

Serum iron analytes in healthy and diseased Florida manatees (Trichechus manatus latirostris)

Serum iron concentration is usually decreased in true iron deficiency and with inflammatory disease in man and domestic animals. Serum total iron binding capacity (TIBC) may be increased in true iron deficiency and decreased with inflammatory disease. This prospective study was designed to measure serum iron analytes in healthy free-ranging and housed Florida manatees (Trichechus manatus latirostris) of both sexes and various ages and to evaluate the effects of diseases common to manatees on these analytes. Blood samples were collected without anticoagulant from 137 healthy free-ranging manatees, 90 healthy housed manatees and 74 free-ranging diseased manatees, and serum was prepared by centrifugation. Serum iron concentration and unsaturated iron binding capacity were measured colourimetrically, and TIBC and percent transferrin saturation with iron were calculated. Serum amyloid A (SAA) was measured to assist in the health assessment of manatees and provide evidence of inflammation in diseased manatees. Based on the serum iron analytes, iron availability was lower in immature manatees compared with adults, and it was lower in housed manatees compared with free-ranging manatees. In contrast to other mammals studied, serum iron concentration was elevated rather than depressed in late pregnancy. Serum iron concentrations and transferrin saturation with iron percentages were significantly lower, and SAA concentrations were significantly higher, in diseased (ill and injured) manatees compared with healthy manatees. Serum iron concentration and transferrin saturation with iron values were negatively correlated with SAA concentrations, and manatees with the highest SAA concentrations had lower serum TIBC values. These findings indicate that inflammation is the major factor responsible for alterations in iron analytes in diseased manatees. Consequently, hypoferraemia may be used as supportive evidence of inflammatory disease in manatees (unless haemorrhage is also present). A decision threshold of ≤13.8 μmol/l was determined for hypoferraemia using receiver operating curve analysis. Based on studies in man and domestic animals, iron therapy is unnecessary for manatees with hypoferraemia associated with inflammation and has the potential for causing tissue damage and increased susceptibility to bacterial infections.

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USGS2019

Conservation easements and coastal armoring: Protecting sea turtle nesting habitat through property ownership

To determine the relationship between the intent of owners of homes located near sea turtle nesting beaches in the state of Florida to engage in coastal conservation easements (CCE), the theory of planned behavior (TPB), environmental identity (EI) and relevant demographics were analyzed. As CCEs are a novel application of a proven conservation tool, a statewide survey was administered to 1274 property owners living within a mile of a protected section of sea turtle nesting habitat (e.g. state park, preserve, wildlife refuge). Multiple linear regression showed coastal property owners were more likely to engage with a CCE if they believed they had the ability and opportunity, held positive attitudes about entering into a CCE, and identified more favorably with potential CCE motivators for property owners. These motivators include receiving assistance from a conservation organization to manage their beachfront land; conserving beach habitat; obtaining annual tax deductions; and trusting the organization administering a CCE. Knowing these motivators and demographics of coastal property owners can help aid coastal land conservationists in crafting strategies to conserve sea turtle nesting beaches.

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USGS2019

Genetic Characterization of Non-Native African Jewelfish, Hemichromis letourneuxi Sauvage 1880, in Florida

The African Jewelfish, Hemichromis letourneuxi , is an invasive, predatory cichlid fish introduced at least once to Florida. Its native range is in northern Africa. First encountered in Miami in the 1960s, it has since been found west and north within the State of Florida. It thrives in a wide range of aquatic habitats, including shallow, vegetated or rocky areas of canals, tidal creeks, rivers, and marshes. We generated mitochondrial DNA sequences from 6 Florida localities, and 1 Mexico population. The resulting tree describes recent historical relationships among populations. Nearly all Florida populations of African Jewelfish are intermixed, supporting a single invasion, with one possible exception: samples from the Tampa Bay locality are distinct and may represent a separate introduction. Samples obtained from the Mexico locality, previously identified as Hemichromis guttatus (Spotted Jewelfish), appear to be genetically identical to, and indistinguishable from the H. letourneuxi sampled in Florida localities.

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