Peninsular Florida Research Articles

Multi-model Subseasonal Precipitation Forecasts over the Contiguous United States: Skill Assessment and Statistical Postprocessing

AbstractThis study assessed multi-model subseasonal precipitation forecasts (SPFs) from eight subseasonal experiment (SubX) models over the contiguous United States (CONUS) and explored the generalized extreme value distribution (GEV)-based ensemble model output statistics (EMOS) framework for postprocessing multi-model ensemble SPF. The results showed that the SubX SPF skill varied by location and season, and the skill were relatively high in the western coastal region, north-central region, and Florida peninsula. The forecast skill was higher during winter than summer seasons, especially for lead week 3 in the northwest region. While no individual model consistently outperformed the others, the simple multi-model ensemble (MME) demonstrated a higher skill than any individual model. The GEV-based EMOS approach dramatically improved the MME subseasonal precipitation forecast skill at long lead times. The continuous ranked probability score (CRPS) was improved by approximately 20% in week 3 and 43% in lead week 4; the 5-mm Brier skill score (BSS) was improved by 59.2% in lead week 3 and 50.9% in lead week 4, with the largest improvements occurring in the northwestern, north-central, and southeastern CONUS. Regarding the relative contributions of the individual SubX model to the predictive skill, the NCEP model was given the highest weight at the shortest lead time, but the weight decreased dramatically with the increase in lead time, while the CESM, EMC, NCEP, and GMAO models were given approximately equal weights for lead weeks 2-4. The presence of active MJO conditions notably increased the forecast skill in the north-central region during weeks 3-4, while the ENSO phases influenced the skill mostly in the southern regions.

Studies in the vascular flora of the southeastern United States. VII

As part of ongoing efforts to understand, document, and conserve the flora of southeastern North America, we propose two new species, the recognition of a usually synonymized variety, the acceptance of two species of Waltheria as being present in peninsular Florida, taxonomic acceptance of a sometimes deprecated species transferred with a new name into a different genus, and we clarify the distribution and ecology of a species. In Carex (Cyperaceae), we re-analyze infrataxa in Carex intumescens and recommend the recognition of two varieties, a taxonomic schema first proposed in 1893, but usually not followed in the 128 years since. In Euphorbia (Euphorbiaceae), a careful assessment of south Florida material of Euphorbia subg. Chamaesyce sect. Anisophyllum subsect. Hypericifoliae reveals the need for taxonomic changes to best classify endemic representatives of this group, resulting in the naming of a new species, and a new name at species rank in Euphorbia for a taxon first named in Chamaesyce and sometimes subsequently treated at only varietal rank in Euphorbia. Chamaecrista deeringiana (Fabaceae, subfamily Caesalpinioideae) has been repeatedly misinterpreted to include two different and disjunct population systems with differing morphologies and habitats, which are here interpreted as separate species, one newly named and the other Chamaecrista deeringiana returned to its original and narrower interpretation as a south Florida endemic. Waltheria (Malvaceae) has sometimes been interpreted as being represented in Florida by a single taxon, Waltheria indica, but we disentangle the concepts of the widespread W. indica and the West Indian W. bahamensis and clarify that both are present in the southeastern United States. We reconsider the occurrence and habitat of Toxicoscordion nuttallii (Melanthiaceae) in three states in which it has been reported as a rare species, Mississippi, Missouri, and Louisiana, and remove it from the Mississippi flora as a garbled and false report. In Louisiana, its occurrence in calcareous prairie complexes limits its potential occurrence in the state to a specialized and rare habitat, but careful exploration of habitat remnants may result in the discovery of additional populations. Taxonomic studies and re-assessments of this kind are critical in laying the best scientific foundation for regulatory, policy, and land conservation decisions. This paper names or makes the case for the renewed acceptance of six species with range-wide conservation concern: one Critically Imperiled (G1 – Euphorbia ogdenii), one Imperiled (G2 – E. hammeri), and four Vulnerable (G3 – E. garberi, E. porteriana, Chamaecrista deeringiana, C. horizontalis).

Population Genomics of the Commercially Important Gulf of Mexico Pink Shrimp Farfantepenaeus duorarum (Burkenroad, 1939) Support Models of Juvenile Transport Around the Florida Peninsula

The Gulf of Mexico pink shrimp, Farfantepenaeus duorarum, supports large fisheries in the United States and Mexico, with nearly 7,000 tons harvested from the region in 2016. Given the commercial importance of this species, management is critical: in 1997, the southern Gulf of Mexico pink shrimp fishery was declared collapsed and mitigation strategies went into effect, with recovery efforts lasting over a decade. Fisheries management can be informed and improved through a better understanding of how factors associated with early life history impact genetic diversity and population structure in the recruited population. Farfantepenaeus duorarum are short-lived, but highly fecund, and display high variability in recruitment patterns. To date, modeling the impacts of ecological, physical, and behavioral factors on juvenile settlement has focused on recruitment of larval individuals of F. duorarum to nursery grounds in Florida Bay. Here, we articulate testable hypotheses stemming from a recent model of larval transport and evaluate support for each with a population genomics approach, generating reduced representation library sequencing data for F. duorarum collected from seven regions around the Florida Peninsula. Our research represents the first and most molecular data-rich study of population structure in F. duorarum in the Gulf and reveals evidence of a differentiated population in the Dry Tortugas. Our approach largely validates a model of larval transport, allowing us to make management-informative inferences about the impacts of spawning location and recruitment patterns on intraspecific genetic diversity. Such inferences improve our understanding of the roles of non-genetic factors in generating and maintaining genetic diversity in a commercially important penaeid shrimp species.

Further occurrences of melanism in a northern, peripheral, population of Bobcat (<i>Lynx rufus</i>)

Although melanism is understood to occur commonly among some felids, it is reported to be most frequent among cat species that occur in humid, tropical, and densely vegetated habitats. Previously, a single record of a melanistic Bobcat (Lynx rufus) from eastern Canada (New Brunswick) appeared to be a northern outlier, with all other reports of melanism in this species restricted to the warm, humid, climate of southern peninsular Florida. Here, I document a further five occurrences of melanism in Bobcat from New Brunswick and review evidence that a mutation in an agouti-signalling protein gene may be responsible for melanism in New Brunswick Bobcats.

Climate Change and Security: The Case of Florida

The low-lying subtropical Florida Peninsula, surrounded on three sides by the sea, is highly vulnerable to the manifestations of climate change. Rising sea levels are already responsable for significant coastal erosion that threatens infrastructure, real estate, and Florida’s subtropical habitats. The State lies in the path of hurricanes whose winds and storm surges pose great threats to life and property. Rising temperatures are likely to impact the most vulnerable sectors of the population, adversely impact agriculture, and threaten the health of Florida’s coral reef ecosystems. Some local governments are beginning to address the threats. However, the State of Florida irresponsibly continues to take a “business-as-usual” path.

Biogeography and predictors of wildlife killed on roads at peninsular Florida State Parks

AbstractWildlife‐vehicle collisions (WVCs) are a major source of wildlife mortality and should affect regional wildlife diversity and abundance, yet most WVC studies are locally scaled. Here, we evaluated biogeographic diversity (i.e., species richness, effective diversity) and abundance of WVCs at state parks across the Florida peninsula to answer two questions aimed to help inform wildlife conservation efforts: which parks have greatest WVC diversity, and why? We processed and compiled 9,254 WVC survey records collected by Florida State Parks personnel at 42 parks during a decade (2005–2015). Data for birds (138 species), mammals (35 species), reptiles (64 species), and all taxa combined were analyzed for patterns among parks (for the first question) and for biogeographic, climatic, ecoregion, and anthropogenic predictors of those patterns (for the second). Predictors represented nonexclusive alternative a priori hypotheses and were evaluated by model comparison. Parks differed widely in WVC diversity and abundance; we identify “hot spot” parks where management may most effectively reduce WVCs. Biogeographic and anthropogenic hypotheses were supported, but climatic and ecoregion hypotheses were not. Models for overall diversity fit data better (R2s > 0.50) than did models for specific taxa (e.g., birds). Larger parks closer to Florida's highly populated Atlantic Coast and with greater park attendance and perhaps faster speeds on adjacent roads have more WVC diversity and numbers. Of these predictors, attendance and speed limits are manageable. Traffic management in and near‐identified “hot spot” parks in Florida can most effectively reduce WVC effects on wildlife populations and diversity amidst a growing human population.

High density and survival of a native small carnivore, the Florida spotted skunk (Spilogale putorius ambarvalis), in south-central Florida

Abstract The eastern spotted skunk (Spilogale putorius) is a species of conservation concern across much of its range and has experienced a population decline since the 1940s. Little is known about the Florida spotted skunk (S. p. ambarvalis), a subspecies endemic to peninsular Florida, but previous studies and the frequency of incidental observations suggest that populations of this subspecies might be more abundant than the two eastern spotted skunk subspecies that occur elsewhere. To better understand the status and demography of the Florida spotted skunk, we assessed the density and survival of a population occurring predominantly in dry prairie habitat in south-central Florida. To obtain density estimates, we trapped spotted skunks on a mark–recapture grid over 11 independent 4-day trapping sessions from 2016 to 2018. To obtain survival estimates, we monitored weekly survival of 38 radiocollared spotted skunks (20 collared initially in 2016 and 18 collared initially in 2017) from February 2016 to August 2017. We captured a minimum of 91 unique spotted skunks on 404 occasions on the mark–recapture grid and our density estimates ranged from 6.52 ± 2.93 skunks/km2 to 23.29 ± 7.65 skunks/km2, depending on trapping session, but seasonal differences in density were not significant. The sex ratio of spotted skunks at our site was 1.0M:3.8F. Mean annual survival for all spotted skunks was 0.714 (0.503–0.925, 95% CI), and sex, season, and year did not have significant effects on survival. This survival estimate is the highest reported thus far for any skunk species. Collectively, the density and survival estimates from our study are higher than those of many other mephitids and mustelids of similar size, and these findings reinforce the value of studying locally abundant populations of small carnivores to better inform the conservation, management, and potential restoration of these species in the future.

Spatial variations of North Atlantic landfalling tropical cyclone wind speed decay over the continental United States

AbstractUnderstanding tropical cyclone wind speed decay during the post-landfall stage is critical for inland hazard preparation. This paper examines the spatial variation of wind speed decay of tropical cyclones over the continental United States. We find that tropical cyclones making landfall over the Gulf Coast decay faster within the first 24 hours after landfall than those making landfall over the Atlantic East Coast. The variation of the decay rate over the Gulf Coast remains larger than that over the Atlantic East Coast for tropical cyclones that had made landfall more than 24 hours prior. Besides an average weaker tropical cyclone landfall intensity, the near-parallel trajectory and the proximity of storms to the coastline also help to explain the slower post-landfall wind speed decay for Atlantic East Coast landfalling tropical cyclones. Tropical cyclones crossing the Florida peninsula only slowly weaken after landfall, with an average of less than 20% post-landfall wind speed drop while transiting the state. The existence of these spatial variations also brings into question the utility of a uniform wind decay model. While weak intensity decay over the Florida peninsula is well estimated by the uniform wind decay model, the error from the uniform wind decay model increases with tropical cyclones making direct landfall more parallel to the Atlantic East Coast. The underestimation of inland wind speed by the uniform wind decay model found over the western Gulf Coast brings attention to the role of land-air interactions in the decay of inland tropical cyclones.

Breeding Ecology of Mottled Ducks: A Review

ABSTRACTMottled ducks (Anas fulvigula) are endemic to the Gulf Coast of North America, and their range stretches from Alabama to the Laguna Madre of Mexico, with a distinct population in peninsular Florida and an introduced population in South Carolina. As one of the few non‐migratory ducks in North America, mottled ducks depend on a variety of locally available habitat throughout the annual cycle, and threats to these landscapes may affect mottled ducks more acutely than migratory species. Annual population monitoring has revealed declines in mottled duck populations in Texas and Louisiana since 2008, and the genetic integrity of the Florida population has been muddled by the presence of large numbers of feral mallards (Anas platyrhynchos) resulting in hybridization. Similar to other closely related dabbling ducks, mottled duck populations are influenced by recruitment and breeding season survival, so changes in these factors may contribute to population decline. Accordingly, researchers have attempted to address various aspects of mottled duck breeding season ecology and population dynamics since the 1950s. We conducted a literature review on this topic by searching a combination of key terms using Google Scholar, including mottled duck, nesting ecology, habitat use, breeding incidence, nest success, brood, and breeding season survival, and followed citation trees to eventually aggregate information from nearly 50 publications on mottled duck breeding ecology. Our review concluded that mottled ducks use brackish and intermediate coastal marsh, including managed impoundments, and agricultural land during the breeding season. Their nests can be found in pastures, levees, dry cordgrass marsh, cutgrass marsh, spoil banks, and small islands. Nesting propensity and nest success estimates are often lower than other waterfowl species that are characterized by stable or increasing populations. Broods use wetlands composed of a mix of open water with submerged and emergent vegetation. Breeding season survival is higher for the Florida population than the western Gulf Coast population, but adult survival in both geographies is comparable to (or higher than) that of other dabbling duck species. Breeding habitat use, breeding season survival, and nest‐site selection and success have been studied extensively in mottled ducks, whereas information on nesting propensity, renesting intensity, and post‐hatch ecology is lacking. © 2021 The Wildlife Society.

Pooling Data Improves Multimodel IDF Estimates over Median-Based IDF Estimates: Analysis over the Susquehanna and Florida

AbstractTraditional multimodel methods for estimating future changes in precipitation intensity, duration, and frequency (IDF) curves rely on mean or median of models’ IDF estimates. Such multimodel estimates are impaired by large estimation uncertainty, shadowing their efficacy in planning efforts. Here, assuming that each climate model is one representation of the underlying data generating process, i.e., the Earth system, we propose a novel extension of current methods through pooling model data: (i) evaluate performance of climate models in simulating the spatial and temporal variability of the observed annual maximum precipitation (AMP), (ii) bias-correct and pool historical and future AMP data of reasonably performing models, and (iii) compute IDF estimates in a nonstationary framework from pooled historical and future model data. Pooling enhances fitting of the extreme value distribution to the data and assumes that data from reasonably performing models represent samples from the “true” underlying data generating distribution. Through Monte Carlo simulations with synthetic data, we show that return periods derived from pooled data have smaller biases and lesser uncertainty than those derived from ensembles of individual model data. We apply this method to NA-CORDEX models to estimate changes in 24-h precipitation intensity–frequency (PIF) estimates over the Susquehanna watershed and Florida peninsula. Our approach identifies significant future changes at more stations compared to median-based PIF estimates. The analysis suggests that almost all stations over the Susquehanna and at least two-thirds of the stations over the Florida peninsula will observe significant increases in 24-h precipitation for 2–100-yr return periods.

Lessons from Four Decades of Monitoring Vegetation and Fire: Maintaining Diversity and Resilience in Florida’s Uplands

Worldwide, humans are altering the fire regimes (fire‐return intervals, severity, seasonality) of fire‐prone ecosystems, fragmenting natural landscapes, and altering climates. Efforts to restore fire regimes in natural areas are usually guided by fire management plans (FMP) that rely on prescribed burning. Despite the common use of FMPs, limited efforts have gone to assessing vegetative and faunal responses. While some insights into responses to fire from short‐term studies are available, there is less knowledge about FMP outcomes applied over multiple decades. Peninsular Florida hosts many fire‐prone communities including globally threatened Florida scrub. We repeatedly sampled species composition and abundance during a 38‐yr period (1977–2015) at 11 upland stands including wet prairies, flatwoods, and Florida scrub (i.e., oak scrub, rosemary scrub, hickory scrub). A total of 22 fires impacted the stands with individual stands experiencing as few as 2 and up to 11 fires. There was no invasion of non‐native plants following fires and stands showed remarkable ecological resilience with limited change in species composition and modest abundance shifts due to differential recovery rates. Importantly, ecological resilience was not eroded with repeated fire. Species richness, evenness, and diversity were significantly higher at the end vs. beginning of our study, suggesting that current fire regimes are within the range of those with which species evolved. While resprouting shrubs and trees persevered under a range of fire‐return intervals, an obligate‐seeding shrub was adversely impacted by fires more frequent than FMP‐recommended intervals. Several lessons are apparent from our findings. Best practice should: use the full range of fire‐return variation at evolutionarily appropriate intervals; utilize natural fire seasons to the extent possible; compare outcomes and modify prescriptions as necessary to meet FMP goals; give special consideration to burn units with embedded associations of widely differing fire regimes than principal associations in order to maintain diversity of both associations; and account for climate change in FMPs since fire behavior, frequency, and community responses to fire will likely change in the coming decades. Outcomes of FMPs must be carefully evaluated to ensure prescriptions are evolutionarily appropriate and to ameliorate the impacts of altered climates.

Breeding Cultivars from Blueberry × Deerberry Hybrids: Progress and Prospects

Vaccinium stamineum (deerberry) is a highly variable diploid species in section Polycodium. Deerberry is native on excessively drained sandy soils from southeastern Ontario, south through the Florida peninsula to Lake Okeechobee, west to eastern Texas and southeastern Kansas. The V. stamineum used in this study were tall plants (2–4 m) native in north Florida, with a plant architecture similar to rabbiteye blueberry (V. virgatum). Starting in 2013 with crosses between tetraploid highbush cultivars (section Cyanococcus) and colchicine-doubled V. stamineum, hundreds of F1 and thousands of later-generation seedlings were grown and evaluated in high-density field nurseries at Citra in North Florida. The populations studied included F1, F2, backcrosses to each parent species, and BC1 × BC1 seedlings. The goal of the study was to assess the feasibility of introgressing into highbush blueberry cultivars desirable traits from V. stamineum (drought tolerance, red-flesh berries, new flavor components, open flowers with short corolla cups and exserted anthers and stigmas) without introducing horticulturally problematic characteristics (bitter skin, berries that shatter when ripe, difficult vegetative propagation). Vigor averaged very low in F1 seedlings, higher in F2 seedlings and in seedlings from backcrosses to V. stamineum, and highest in seedlings from backcrosses to highbush. Most crosses yielded numerous plump seeds, but crosses to produce F1 hybrids yielded fewer than 10% as many seeds as highbush × highbush crosses. Most vegetative, flower, and fruit traits that differentiate highbush from V. stamineum were intermediate in F1 seedlings. Backcross seedlings more closely resembled the recurrent parent. Variability in morphological characters was high in every generation, giving much opportunity for selection. Some seedlings from backcrosses to highbush (≈5%) appeared to have the vigor, berry quality, and yield potential required in commercial cultivars. Producing highbush cultivars that strongly express a particular V. stamineum trait might best be accomplished by growing large, segregating F2 populations from which parents for backcrosses can be selected.

Vector Competence of Florida Culicoides insignis (Diptera: Ceratopogonidae) for Epizootic Hemorrhagic Disease Virus Serotype-2.

Epizootic hemorrhagic disease virus (EHDV; family Reoviridae, genus Orbivirus) is an arthropod-borne virus of ungulates, primarily white-tailed deer in North America. Culicoides sonorensis, the only confirmed North American vector of EHDV, is rarely collected from Florida despite annual virus outbreaks. Culicoides insignis is an abundant species in Florida and is also a confirmed vector of the closely related Bluetongue virus. In this study, oral challenge of C. insignis was performed to determine vector competence for EHDV serotype-2. Field-collected female midges were provided bovine blood spiked with three different titers of EHDV-2 (5.05, 4.00, or 2.94 log10PFUe/mL). After an incubation period of 10 days or after death, bodies and legs were collected. Saliva was collected daily from all females from 3 days post feeding until their death using honey card assays. All samples were tested for EHDV RNA using RT-qPCR. Our results suggest that C. insignis is a weakly competent vector of EHDV-2 that can support a transmissible infection when it ingests a high virus titer (29% of midges had virus positive saliva when infected at 5.05 log10PFUe/mL), but not lower virus titers. Nevertheless, due to the high density of this species, particularly in peninsular Florida, it is likely that C. insignis plays a role in the transmission of EHDV-2.

Variation in Seagrass-Associated Macroinvertebrate Communities Along the Gulf Coast of Peninsular Florida: An Exploration of Patterns and Ecological Consequences

Seagrasses form vast meadows of structurally complex habitat that support faunal communities with greater numbers of species and individuals than nearby unstructured habitats. The Gulf coast of peninsular Florida represents a natural laboratory ideally suited to the study of processes that shape seagrass-associated invertebrate and fish communities within meadows of a single species of seagrass, Thalassia testudinum. This suitability arises from a pronounced structural and chemical gradient that exists over ecologically relevant spatial and temporal scales, as revealed by extensive monitoring of water quality and seagrass. We hypothesized that seagrass-associated invertebrate communities would vary across five estuarine systems spread along a spatial gradient in phosphorus concentration, an important driver of seagrass and phytoplankton growth in this region. The quantitative results based on data acquired at 25 stations (75 samples, 52,086 specimens, and 161 taxa) indicated that each of the five estuarine systems were distinct with regard to species composition and differences among systems were driven by abundant or relatively common species. In addition, we found evidence to indicate food webs in seagrass meadows along this gradient may differ, especially in the relative dominance of algal grazers and predatory invertebrates. These changes in species composition and trophic roles could be driven by phosphorus directly, through increases in rates of primary production with higher concentrations of phosphorus, or indirectly, through nutrient-mediated changes in the physical structure of the seagrass canopy. Our results suggest that differences in the habitat created by T. testudinum under differing phosphorus supplies lead to ecologically significant shifts in macroinvertebrate communities.

Potential Distribution of Aedes (Ochlerotatus) scapularis (Diptera: Culicidae): A Vector Mosquito New to the Florida Peninsula.

Simple SummaryAedes scapularis is an important mosquito species capable of transmitting viruses and parasites to humans and animals. Aedes scapularis was previously known to occur throughout large portions of the Americas, from the lower Rio Grande Valley of southern Texas to Argentina and on several Caribbean Islands. Recently, this mosquito became established in southern Florida, marking the first time Ae. scapularis was found on the Florida Peninsula. Now that Ae. scapularis has reached the Florida Peninsula, it is expected to continue to expand its geographic distribution to fill contiguous areas with suitable environments. Here, we use a modeling approach that correlates environmental variables with known geographic collection locations of Ae. scapularis to predict the potential distribution of this species. The output of this model provides new information for mosquito control and public health agencies to help monitor the spread of this exotic vector mosquito and suggests a need for surveillance for the expansion of this mosquito in many of Florida’s coastal counties.Aedes scapularis is a neotropical mosquito known to transmit pathogens of medical and veterinary importance. Its recent establishment in southeastern Florida has potential public health implications. We used an ecological niche modeling approach to predict the abiotic environmental suitability for Ae. scapularis across much of the Americas and Caribbean Islands. Georeferenced occurrence data obtained from the Global Biodiversity Inventory Facility and recent collection records of Ae. scapularis from southern Florida served as input for model calibration. Environmental layers included bioclimatic variables provided in 2000 to 2010 average Modern Era Retrospective-analysis for Research and Applications climatic (MERRAclim) data. Models were run in the software program Maxent. Isothermality values often found in costal environments, had the greatest contribution to model performance. Model projections suggested that there are areas predicted to be suitable for Ae. Scapularis across portions of the Amazon Basin, the Yucatán Peninsula, the Florida Peninsula, and multiple Caribbean Islands. Additionally, model predictions suggested connectivity of highly suitable or relatively suitable environments spanning the United States Gulf Coast, which may facilitate the geographic expansion of this species. At least sixteen Florida counties were predicted to be highly suitable for Ae. scapularis, suggesting that vigilance is needed by vector control and public health agencies to recognize the further spread of this vector.

Estimating the Thermodynamic and Dynamic Contributions to Hydroclimatic Change over Peninsular Florida

AbstractIn this study we examine the thermodynamically and dynamically forced hydroclimatic changes in the four representative seasons over Peninsular Florida (PF) from an unprecedented pair of high-resolution regional coupled ocean–atmosphere model simulations conducted at 10-km grid spacing for both the atmospheric and the oceanic components forced by one of the global climate models that participated in CMIP5. The model simulation verifies reasonably well with the observations and captures the distinct seasonal cycle of the region. The projected change in the freshwater flux in the mid-twenty-first century (2041–60) relative to the late twentieth century (1986–2005) shows a precipitation deficit in the summer over PF, which is statistically significant. This projected change in freshwater flux over PF is enabled by the strengthening of the anticyclonic North Atlantic subtropical high circulation with corresponding changes in divergence of moisture, advection of moisture from changes in the winds and in the change in humidity gradient, and from the change in moisture flux convergence by the transient eddies. These changes suggest that a future warm climate could witness a drier summer over PF at the expense of a wetter West Florida Shelf. The analysis conducted in this study reveals that the changes in atmospheric circulation have a significant impact on the hydroclimate, far more than that implied by the Clausius–Clapeyron equation from changes in temperature.

Phylogenetic relationships, genetic diversity and biogeography of menhadens, genus Brevoortia (Clupeiformes, Clupeidae)

Brevoortia Gill 1861 is a genus of the Clupeidae (Teleostei) that includes six species of fishes commonly known as menhadens in eastern North America and “savelhas” or “saracas” in southeastern South America. Species of Brevoortia are important components of the marine food web of coastal ecosystems in the Atlantic and contribute significantly to fisheries. In this study, the first phylogenetic and biogeographic hypotheses including all species of Brevoortia are presented. A total of 113 specimens were analyzed using three molecular markers (two mitochondrial: COI and 16s; and one nuclear: RAG2). Maximum Parsimony, Maximum Likelihood and Bayesian Inference were employed to estimate phylogenetic relationships. A Bayesian multispecies coalescent approach was used to estimate a dated phylogeny, which supported biogeographic analyses of ancestral geographic ranges. Results corroborate previous hypotheses that the four North Atlantic species are grouped in two clades, one composed of B. tyrannus (Latrobe, 1802) and B. patronus Goode, 1878, and the second including B. smithi Hildebrand, 1941 and B. gunteri Hildebrand, 1948. The South Atlantic B. aurea (Spix and Agassiz, 1829) and B. pectinata (Jenyns, 1842) form a third clade, which is sister to the clade composed of B. smithi and B. gunteri. The monophyly and validity of the six nominal species of Brevoortia were not supported. Results also indicate that Brevoortia originated in the North Atlantic during the middle Miocene (about 15 Mya). A cooling event of the tropical Atlantic at around 10 Mya likely facilitated the range expansion of the genus to the South Atlantic, whereas a significant warming of the tropical Atlantic waters during the late Miocene at 6–7 Mya possibly promoted the isolation between the northern and southern counterparts of that ancestral lineage. The relevance of the Florida Peninsula in association with sea level fluctuations for the diversification within Brevoortia is also discussed.

Phylogeography and demographic expansion in the widely distributed horned passalus beetle, Odontotaenius disjunctus (coleoptera: Passalidae)

Dynamic climatic oscillations during the Pleistocene had profound effects on the distribution of species across North America. Although the role of historical climate change on speciation remains controversial, the impact on genetic variation within species has been well documented. Analyses of mtDNA sequences from the cytochrome oxidase I gene (911 bp) for 115 individuals of Odontotaenius disjunctus was combined with ecological niche modelling (ENM) to infer the demographic and population differentiation scenarios under present and past conditions. We inferred three lineages that diverged during the Pleistocene and replace each other geographically across the eastern United States. One of these lineages traverses previously identified genetic barriers for terrestrial animals including the Mississippi and Apalachicola Rivers and the Appalachian Mountains. We observed overlapping ranges between two haplotype groups as well as a region of secondary contact associated with ecological transition zone in northern Florida. The two continental lineages depict a genetic signature of a recent population increase associated with expanding niche envelope, whereas the clade restricted to peninsular Florida shows stable populations in a shrinking niche envelope. Given the lack of ecological separation, overlapping distribution of haplogroups and the presence of secondary contact zones, the taxonomic status of these lineages must await robust testing using multilocus DNA data to assess species boundaries.

Dissolved organic nutrients at the interface of fresh and marine waters: flow regime changes, biogeochemical cascades and picocyanobacterial blooms—the example of Florida Bay, USA

The availability of dissolved inorganic and organic nutrients and their transformations along the fresh to marine continuum are being modified by various natural and anthropogenic activities and climate-related changes. Subtropical central and eastern Florida Bay, located at the southern end of the Florida peninsula, is classically considered to have inorganic nutrient conditions that are in higher-than-Redfield ratio proportions, and high levels of organic and chemically-reduced forms of nitrogen. However, salinity, pH and nutrients, both organic and inorganic, change with changes in freshwater flows to the bay. Here, using a time series of water quality and physico-chemical conditions from 2009 to 2019, the impacts of distinct changes in managed flow, drought, El Niño-related increases in precipitation, and intensive storms and hurricanes are explored with respect to changes in water quality and resulting ecosystem effects, with a focus on understanding why picocyanobacterial blooms formed when they did. Drought produced hyper-salinity conditions that were associated with a seagrass die-off. Years later, increases in precipitation resulting from intensive storms and a hurricane were associated with high loads of organic nutrients, and declines in pH, likely due to high organic acid input and decaying organic matter, collectively leading to physiologically favorable conditions for growth of the picocyanobacterium, Synechococcus spp. These conditions, including very high concentrations of NH4+, were likely inhibiting for seagrass recovery and for growth of competing phytoplankton or their grazers. Given projected future climate conditions, and anticipated cycles of drought and intensive storms, the likelihood of future seagrass die-offs and picocyanobacterial blooms is high.

Impacts of Tropical Cyclones on Longleaf Pine Ecosystems of Florida: Tropical Cyclogenesis, Landfall Frequencies, and Climate Change

Tropical storms and hurricanes (collectively hereafter,tropical cyclones) are among the most destructive forces in nature. These threats are of particular concern to human populations and ecosystems of coastal areas of the southeastern United States, most especially in the State of Florida. This review begins with an overview of the effects of tropical cyclones on Florida’s most conspicuous terrestrial ecosystem—longleaf pine. Environmental factors leading to tropical cyclogenesis will also be reviewed, with a specific focus on (1) landfall history in Florida, and (2) the potential relationship between climate change and the frequency/intensity of tropical cyclones in the North Atlantic Ocean. Given its geographical distribution, it is not surprising that longleaf pine has long been impacted by tropical cyclones of the North Atlantic. Tropical cyclones are formed from a complex combination of meteorological conditions, driven initially by the release of excess heat from the surface waters of the ocean, along with an unstable atmosphere comprising air temperatures decreasing and wind speeds increasing with altitude. Among the coastal counties from Texas to Maine, those of Florida have experienced by far the highest frequency of tropical cyclones, especially the southern tip of peninsular Florida, with its most populous county (Miami-Dade) receiving 25 hits from 1900 to 2010, second only to Monroe County (32 hits) during that period. Frequencies of all categories of cyclones have increased significantly from 1850 to the present. Cyclone frequencies were significantly correlated with increases in air and ocean temperatures, both of which have increased over the past, suggesting a causal relationship with anthropogenic climate change. Of future concern is how increases in frequencies and intensities of tropical cyclones will negatively affect the structure and function of these ecologically and economically important longleaf pine ecosystems.