Apalachicola River Research Articles

Erosive dynamics of channels incised by subsurface water flow

We propose a dynamical model for channels incised into an erodible bed by subsurface water flow. The model is validated by the time‐resolved topographic measurements of channel growth in a laboratory‐scale experiment. Surface heights in the experiment are measured via a novel laser‐aided imaging technique. The erosion rate in the model is composed of diffusive and advective components as well as a simple driving term due to the seeping water. Steady driving conditions may exist whenever channels are incised into a flat and level erodible bed by a water table replenished via steady (on average) rainfall. Under such steady driving conditions, the model predicts an asymptotically self‐similar growing shape for the channel transects. Conversely, given a transect shape that evolved under steady driving conditions and an estimate of the erosion rate at the bottom of the channel, granular transport coefficients can be inferred from the static channel shape. We report an estimate of these transport coefficients for a system of ravines incised into unconsolidated sand in the Apalachicola River basin, Florida.

Application of cold neutron prompt-gamma activation analysis in environmental studies of aquatic plants

This paper describes the use of cold-neutron prompt-gamma activation analysis (CNPGAA) to determine carbon, nitrogen, and phosphorus in the aquatic plant Typha domingensis, commonly known as cattail, during spring and fall seasons. According to studies of the Florida Everglades, cattail replaces sawgrass as a result of nutrient enrichment from farm water runoff. Nutrient enrichment, especially phosphorus, in sediment and the water column can lead to undesirable expansion. Early signs of this expansion are apparent in the Apalachicola River floodplain near Apalachicola, Florida, USA. This research project is designed to use cattails as biomonitors of nutrient enrichment in the lower Apalachicola River floodplain. Determination of carbon, nitrogen, and phosphorus in cattail using cold neutron prompt-gamma activation has been developed in our previous studies at the CNPGAA facility at the National Institute of Standards and Technology (NIST), USA. The results of numerous field samples, collected from the study area during spring and fall seasons in 2002, will be presented in this paper.

Valuing nature-based recreation in public natural areas of the Apalachicola River region, Florida

As more people visit natural areas for tourism and recreation purposes, it is becoming increasingly important to understand the value they place on these natural resources. Specifically, tourists to Florida have been increasingly interested in visiting natural areas, forests, parks, and preserves—highlighting the importance of this new and growing phenomenon. We analyze visitors’ demand for nature-based recreation in the Apalachicola River region of Florida using the travel cost method. The results from a count data regression model reveal that on average visitors would pay $74.18 per visit-day for nature-based recreation resulting in a total economic value of $484.56 million attributable to nature-based recreation in the Apalachicola River region. Results of this study provide useful information for natural resources management in the region and a rationale to preserve Florida's unique ecosystems.

Phylogeographic concordance in the southeastern United States: the flatwoods salamander, Ambystoma cingulatum, as a test case

Well-supported, congruent phylogeographic and biogeographic patterns permit the development of a priori phylogeographic and distributional predictions. In the southeastern Coastal Plain of the United States, the common discovery of east-west disjunctions (phylogeographic breaks and species' distributional boundaries) suggests that similar disjunctions should occur in codistributed taxa. Despite the near ubiquity of these disjunctions, the most recent morphological analyses of the flatwoods salamander, Ambystoma cingulatum, indicate that none occur in this low-vagility, Coastal Plain endemic. We conducted molecular and morphological analyses to test whether the flatwoods salamander is an exception to this common biogeographic pattern. Assessing geographic variation in this species is also an important management tool for this threatened, declining amphibian. We demonstrate that flatwoods salamanders, as predicted by comparisons to codistributed taxa, are polytypic with a major disjunction at the Apalachicola River. This drainage is a common site for east-west phylogeographic breaks, probably because repeated marine embayments during the Pliocene and Pleistocene interglacials generated barriers to gene flow. Based on mitochondrial DNA, morphology, and allozymes, we recognize two species of flatwoods salamanders -- Ambystoma cingulatum to the east of the Apalachicola drainage and Ambystoma bishopi to the west. Given this increased diversity, the conservation status of these two taxa may warrant re-evaluation. More generally, these results emphasize that in the absence of taxon-specific data, established comparative patterns can provide strong expectations for designing management units for unstudied species of conservation concern.

Voices of Apalachicola

One of Florida's most endangered river systems is the Apalachicola River and Bay basin, and it is not just the natural areas that are threatened but also the history and culture of its people. In Voices of the Apalachicola, veteran storyteller Faith Eidse, together with the staff of the Northwest Florida Water Management District, has compiled a remarkable collection of oral histories from more than 30 individuals who have lived out their entire lives in this region, including the last steamboat pilot on the Apalachicola-Chattahoochee-Flint river system, sharecroppers who escaped servitude, turpentine workers in Tate's Hell, sawyers of old-as-Christ cypress, bee-keepers working the last large tupelo stand, and a Creek chief descended from a 200-year unbroken line of chiefs. As developers increase pressure and populations grow within the basin, this timely collection captures a fascinating and unique moment in history, recalling a resource that once brimmed with life - bigger oysters, larger sturgeon, healthier Torreya trees. The Apalachicola River system is one of the main resources of water not only for Florida, but also Alabama and Georgia. It flows unimpeded for 106 miles from Lake Seminole - where the Chattahoochee and Flint Rivers merge - through the Florida Panhandle into Apalachicola Bay and finally into the Gulf of Mexico. From emerging technologies to environmental health, Eidse captures the battle to preserve and persevere, providing historic and current photos that show how the basin has changed. Habitat maps indicate where our sensitive species live and land preservation maps illustrate how the state of Florida is trying to protect them.

Comparative phylogeography of unglaciated eastern North America

Regional phylogeographical studies involving co-distributed animal and plant species have been conducted for several areas, most notably for Europe and the Pacific Northwest of North America. Until recently, phylogeographical studies in unglaciated eastern North America have been largely limited to animals. As more studies emerge for diverse lineages (including plants), it seems timely to assess the phylogeography across this region: (i) comparing and contrasting the patterns seen in plants and animals; (ii) assessing the extent of pseudocongruence; and (iii) discussing the potential applications of regional phylogeography to issues in ecology, such as response to climatic change. Unglaciated eastern North America is a large, geologically and topographically complex area with the species examined having diverse distributions. Nonetheless, some recurrent patterns emerge: (i) maritime - Atlantic vs. Gulf Coast; (ii) Apalachicola River discontinuity; (iii) Tombigbee River discontinuity; (iv) the Appalachian Mountain discontinuity; (v) the Mississippi River discontinuity; and (vi) the Apalachicola River and Mississippi River discontinuities. Although initially documented in animals, most of these patterns are also apparent in plants, providing support for phylogeographical generalizations. These patterns may generally be attributable to isolation and differentiation during Pleistocene glaciation, but in some cases may be older (Pliocene). Molecular studies sometimes agree with longstanding hypotheses of glacial refugia, but also suggest additional possible refugia, such as the southern Appalachian Mountains and areas close to the Laurentide Ice Sheet. Many species exhibit distinct patterns that reflect the unique, rather than the shared, aspects of species' phylogeographical histories. Furthermore, similar modern phylogeographical patterns can result from different underlying causal factors operating at different times (i.e. pseudocongruence). One underemphasized component of pseudocongruence may result from the efforts of researchers to categorize patterns visually - similar patterns may, in fact, not fully coincide, and inferring agreement may obscure the actual patterns and lead to erroneous conclusions. Our modelling analyses indicate no clear spatial patterning and support the hypothesis that phylogeographical structure in diverse temperate taxa is complex and was not shaped by just a few barriers.

A seasonal analysis of riverflow trends

This paper presents a trend analysis of monthly riverflows recorded at the Apalachicola River at Chattahoochee, FL during the 1930–2001 water years. The environmental concern is that increasing urbanization upstream (Atlanta and Columbus, GA) increases downstream riverflows. In statistical terms, our objective is to test whether there are months in which riverflows are significantly increasing. For this purpose, a parsimonious periodic autoregressive moving-average time series model is fitted to the error structure of the series. The covariances of this time series model are then used to assess the significance of monthly and yearly linear trend estimators. In the end, we do not find strong evidence of increasing riverflows.

Phylogeography of the salamander genus Pseudobranchus in the southeastern United States

This study provides an extensive set of mitochondrial cytochrome b sequences for the salamander genus Pseudobranchus of the southeastern United States. These sequences were analysed by multiple phylogenetic methods that support a single set of major phylogeographic divisions for its two corroborated species ( P. axanthus and P. striatus). These phylogeographic divisions overlap with the geographic breakpoints of other freshwater and terrestrial taxa in this region. Collectively, these overlapping patterns highlight the Central Highland and Tifton/Vidalia uplands as a significant barrier to Atlantic vs. Gulf coast groups, while reconfirming the phylogeographic significance of the Altamaha and Apalachicola river drainages. Despite their distinct phylogeographic split, P. striatus from west and east of these uplands are not currently recognizable as separate species according to the concordance principles for species definition.

Flow regime alterations under changing climate in two river basins: implications for freshwater ecosystems

We examined impacts of future climate scenarios on flow regimes and how predicted changes might affect river ecosystems. We examined two case studies: Cle Elum River, Washington, and Chattahoochee–Apalachicola River Basin, Georgia and Florida. These rivers had available downscaled global circulation model (GCM) data and allowed us to analyse the effects of future climate scenarios on rivers with (1) different hydrographs, (2) high future water demands, and (3) a river–floodplain system. We compared observed flow regimes to those predicted under future climate scenarios to describe the extent and type of changes predicted to occur. Daily stream flow under future climate scenarios was created by either statistically downscaling GCMs (Cle Elum) or creating a regression model between climatological parameters predicted from GCMs and stream flow (Chattahoochee–Apalachicola). Flow regimes were examined for changes from current conditions with respect to ecologically relevant features including the magnitude and timing of minimum and maximum flows. The Cle Elum's hydrograph under future climate scenarios showed a dramatic shift in the timing of peak flows and lower low flow of a longer duration. These changes could mean higher summer water temperatures, lower summer dissolved oxygen, and reduced survival of larval fishes. The Chattahoochee–Apalachicola basin is heavily impacted by dams and water withdrawals for human consumption; therefore, we made comparisons between pre-large dam conditions, current conditions, current conditions with future demand, and future climate scenarios with future demand to separate climate change effects and other anthropogenic impacts. Dam construction, future climate, and future demand decreased the flow variability of the river. In addition, minimum flows were lower under future climate scenarios. These changes could decrease the connectivity of the channel and the floodplain, decrease habitat availability, and potentially lower the ability of the river to assimilate wastewater treatment plant effluent. Our study illustrates the types of changes that river ecosystems might experience under future climates. Copyright © 2005 John Wiley & Sons, Ltd.

The Presidio System in Spanish Florida 1565–1763

The Spanish founded at least 16 presidios in Florida, the first at San Agustin in 1565 and the last in Pensacola in 1756. Until 1698, there were no presidios west of the Apalachicola River. Beginning in that year and continuing into the early-18th century, the Spanish founded multiple presidios at Pensacola Bay and at St. Joseph’s Bay. When the Spanish ceded Florida to the British in the Treaty of Paris (1763), which ended the Seven Years’ War and exchanged all of Florida for Havana, only three presidios remained: San Agustin, Pensacola, and San Marcos.

Conservation and management implications of fine-scale genetic structure of Gulf sturgeon in the Pascagoula River, Mississippi

Summary The anadromous Gulf sturgeon occurs along the north central coast of the Gulf of Mexico and is federally listed as threatened. We analyzed fine-scale patterns of Gulf sturgeon population structure, focusing on the Pascagoula River drainage of Mississippi, in reference to movement patterns as determined via telemetry and capture data. We genotyped 361 Gulf sturgeon using eight microsatellite loci including samples from the Pascagoula, Pearl, Escambia, Yellow, Choctawhatchee, and Apalachicola river drainages. Pairwise FST estimates indicated that genetic structure occurs at least at the drainage level. The Pascagoula and Pearl rivers form a western group, demonstrating 100% bootstrap support for a division with drainages to the east. Assignment tests detected non-natal genotypes occurring in all drainages. According to assignment tests, the Pascagoula supports an admixture of individuals, containing minimal influence from drainages to the east (2%) and substantial interaction with the Pearl River (14.1%). The occurrence of Pascagoula River fish in the Pearl was non-reciprocal, observed at 1.1%. After accounting for non-natal genetic diversity within the Pascagoula, there remained a disparity between a pooled Pascagoula group and the only documented spawning site within the drainage located in the Bouie River. We interpret this as an indication of a second genetic stock within the Pascagoula River drainage. Radio telemetry data suggest that spawning likely occurs in the Chickasawhay River, in areas isolated from the Bouie River spawning site by about 350 river kilometers. We emphasize the utility of integrating field and molecular approaches when delineating fine-scale patterns of population structure in anadromous fishes.

Forecasting flows in Apalachicola River using neural networks

AbstractForecasting river flow is important to water resources management and planning. In this study, an artificial neural network (ANN) model was successfully developed to forecast river flow in Apalachicola River. The model used a feed‐forward, back‐propagation network structure with an optimized conjugated training algorithm. Using long‐term observations of rainfall and river flow during 1939–2000, the ANN model was satisfactorily trained and verified. Model predictions of river flow match well with the observations. The correlation coefficients between forecasting and observation for daily, monthly, quarterly and yearly flow forecasting are 0·98, 0·95, 0·91 and 0·83, respectively. Results of the forecasted flow rates from the ANN model were compared with those from a traditional autoregressive integrated moving average (ARIMA) forecasting model. Results indicate that the ANN model provides better accuracy in forecasting river flow than does the ARIMA model. Copyright © 2004 John Wiley & Sons, Ltd.

Conserving Slow‐Growing, Long‐Lived Tree Species: Input from the Demography of a Rare Understory Conifer,Taxus floridana

Abstract: Although land preservation and promotion of successful regeneration are important conservation actions, their ability to increase population growth rates of slow‐growing, long‐lived trees is limited. We investigated the demography ofTaxus floridanaNutt., a rare understory conifer, in three populations in different ravine forests spanning its entire geographic range along the Apalachicola River Bluffs in northern Florida (U.S.A.). We examined spatial and temporal patterns in demographic parameters and projected population growth rates by using four years of data on the recruitment and survival of seedlings and established stems, and on diameter growth from cross‐sections of dead stems. All populations experienced a roughly 10‐fold increase in seedling recruitment in 1996 compared with other years. The fates of seedlings and stems between 8 and 16 mm differed among populations. The fates of stems in two other size classes (the 2‐ to 4‐mm class and the 4‐ to 8‐mm class) differed among both populations and years. Individual stems in all populations exhibited similarly slow growth rates. Stochastic matrix models projected declines in all populations. Stochastic matrix analysis revealed the high elasticity of a measure of stochastic population growth rate to perturbations in the stasis of large reproductive stems for all populations. Additional analyses also indicated that occasional episodes of high recruitment do not greatly affect population growth rates. Conservation efforts directed at long‐lived, slow‐growing rare plants likeTaxus floridanashould both protect established reproductive individuals and further enhance survival of individuals in other life‐history stages, such as juveniles, that often do not appear to contribute greatly to population growth rates.

Stomatopoda (Crustacea: Hoplocarida) from the Shallow, Inshore Waters of the Northern Gulf of Mexico (Apalachicola River, Florida to Port Aransas, Texas)

Six species representing the order Stomatopoda are reported from the shallow, inshore waters (passes, bays, and estuaries) of the northern Gulf of Mexico limited to a depth of 10 m or less, and by the Apalachicola River (Florida) in the east and Port Aransas (Texas) in the west. With the exception of the “live bottom” gonodactylid, Neogonodactylus bredini (Manning), these predatory crustaceans usually inhabit burrows in mud, sand-mud, and sand substrata in coastal and shelf waters. The species treated in this paper are Neogonodactylus bredini (Manning), Lysiosquilla scabricauda (Lamarck), Bigelowina biminiensis (Bigelow), Coronis scolopendra Latreille, Squilla empusa Say, and Gibbesia neglecta (Gibbes). The questionable record of Squilla rugosa Bigelow by Archer (1948) is discussed. A review of the life history, ecology, distribution, and new northern Gulf of Mexico records is provided here for each of these species. Figures and an illustrated key are also presented.

Field Experiment Study of Transient Stratified Flow in an Estuary

An experimental study of stratified flow was conducted in this study. An electromagnetic measurement instrument, the S4 current meter, was used in field data collections of salinity and currents in the lower Apalachicola River estuary, Florida. The S4 current meter has an advantage in field deployments for long periods of time due to its preprogrammable capability for automatic data sampling and recording of fluid flow. Time series of surface and bottom salinity and currents obtained from field experiments were used to characterize the stratified flow at the measurement location in the Apalachicola River. Analysis of field data indicated that the river was strongly stratified. The stratification was affected by the upstream river flow and the downstream tidal variations. Stratification was stronger at high tide than at low tide. By removing the tidal signal using low-passing filtering, subtidal salinity, and currents were obtained to investigate the salinity stratification and currents responses to the changes of fresh water input. Subtidal vertical salinity and velocity profiles were presented at different flow conditions. At high flow conditions, both surface and bottom subtidal currents were in the seaward direction. At low flow conditions, the bottom subtidal currents were in the upstream direction due to the strong effects of density gradients. Empirical regression equations were obtained to quantify the effects of river flow on the subtidal salinity and the bottom currents. Regression analysis indicated good linear relationship between subtidal salinity stratification and the bottom currents.

DISTRIBUTION AND STATUS OF THE ALLIGATOR SNAPPING TURTLE (MACROCHELYS TEMMINCKII) IN GEORGIA

Historically, the alligator snapping turtle (Macrochelys temminckii Harlan) was heavily collected in Georgia to provide meat to soup canneries. With the exception of previous studies of the Flint River population, the current status of this species in Georgia is poorly known. We trapped most navigable streams within the species' range in Georgia, except the Flint River, to evaluate the population status and distribution of this threatened species. Populations in the Chattahoochee River catchment and Spring Creek (Apalachicola River drainage) are more robust than those found elsewhere in the state. Despite extensive trapping, M. temminckii was not caught in the Suwannee River. The current prohibition against collecting this species in Georgia should enhance its ongoing recovery, although the Suwannee River drainage warrants further investigation and possibly more intensive recovery strategies.

EVIDENCE FOR MULTIPLE PLEISTOCENE REFUGIA IN THE POSTGLACIAL EXPANSION OF THE EASTERN TIGER SALAMANDER, AMBYSTOMA TIGRINUM TIGRINUM

Abstract Pleistocene glaciations were important determinants of historical migration and, hence, current levels of genetic diversity within and among populations. In many cases, these historical migrations led to the existence of disjunct populations of plants and animals. However, the origin and timing of arrival of these disjunct populations is often debated. In the current study, we identify potential refugia and estimate the timing of vicariance events of the eastern tiger salamander, Ambystoma tigrinum tigrinum, using mitochondrial sequence data. The results suggest a vicariant event 0.75–2 million years ago, separating the tiger salamanders to the east and west of the Apalachicola River Basin. East of the Appalachians, there appear to be multiple independent refugia with little migration among the remaining populations. In particular, populations along the Atlantic Coastal Plain were likely isolated in a coastal plain refugium in the Carolinas. Migrants from this refugium were the likely source of colonists for populations occupying previously glaciated areas along the northeastern Atlantic Coast. A second potential refugium occurs in the Blue Ridge Mountains of western Virginia. This refugium contains a disjunct population of the eastern tiger salamander, as well as a community of nearly 70 other disjunct plant and animal species. The tiger salamanders here have been isolated from other populations for 200,000–500,000 years. These results suggest that disjunct mountain populations of Coastal Plain species may have existed in situ throughout the Pleistocene in Appalachian refugia. Therefore, these disjunct populations are not of recent origin, but rather exist as relicts of a warmer, more widespread fauna and flora that is now restricted to the Coastal Plain.

Evidence for multiple Pleistocene refugia in the postglacial expansion of the eastern tiger salamander, Ambystoma tigrinum tigrinum.

Pleistocene glaciations were important determinants of historical migration and, hence, current levels of genetic diversity within and among populations. In many cases, these historical migrations led to the existence of disjunct populations of plants and animals. However, the origin and timing of arrival of these disjunct populations is often debated. In the current study, we identify potential refugia and estimate the timing of vicariance events of the eastern tiger salamander, Ambystoma tigrinum tigrinum, using mitochondrial sequence data. The results suggest a vicariant event 0.75-2 million years ago, separating the tiger salamanders to the east and west of the Apalachicola River Basin. East of the Appalachians, there appear to be multiple independent refugia with little migration among the remaining populations. In particular, populations along the Atlantic Coastal Plain were likely isolated in a coastal plain refugium in the Carolinas. Migrants from this refugium were the likely source of colonists for populations occupying previously glaciated areas along the northeastern Atlantic Coast. A second potential refugium occurs in the Blue Ridge Mountains of western Virginia. This refugium contains a disjunct population of the eastern tiger salamander, as well as a community of nearly 70 other disjunct plant and animal species. The tiger salamanders here have been isolated from other populations for 200,000-500,000 years. These results suggest that disjunct mountain populations of Coastal Plain species may have existed in situ throughout the Pleistocene in Appalachian refugia. Therefore, these disjunct populations are not of recent origin, but rather exist as relicts of a warmer, more widespread fauna and flora that is now restricted to the Coastal Plain.

Spatial and temporal variability of phytoplankton biomass and community structure over the continental margin of the northeast Gulf of Mexico based on pigment analysis

Chlorophyll and carotenoid pigment distributions are used to describe spatial and temporal variations in phytoplankton biomass in the water column of the northeastern Gulf of Mexico (NEGOM) between the Mississippi River Delta in Louisiana and Tampa Bay in Florida from November 1997 through August 2000 and to infer seasonal changes in phytoplankton taxonomic composition. Chlorophyll a concentration in the water averaged 0.4 μg/l but ranged as high as 12 μg/l on nine cruises in this region during the 3 year period. The spatial distribution of chlorophyll a appeared to be controlled by riverine and estuarine input of nutrient-enriched freshwater. The Mississippi and Apalachicola River systems were the two main controlling features for the spatial distribution of chlorophyll in the NEGOM area. On average, the near-surface as well as subsurface waters near the Mississippi River–Mobile Bay outflow regions had the highest chlorophyll a concentrations of the study area during the 3 years. Subsurface waters near the Apalachicola River outflow region also had consistently high chlorophyll a concentrations during the nine cruises, even though the near-surface waters in this region did not. Algorithmic analyses of pigment composition indicated that prymnesiophytes, prokaryotes, cyanobacteria, diatoms, and pelagophytes were the major phytoplankton taxa on the NEGOM continental margin. On average, prymnesiophytes accounted for 25–40% of total chlorophyll in the water column over this continental margin during the 3 year period. Prokaryotes averaged 14–38% of chlorophyll a in the water column. Diatoms, which contributed 6–13% of chlorophyll a, were primarily found in inner shelf coastal waters. In contrast, prymnesiophytes and pelagophytes reached highest abundances in outer shelf and slope waters. Phytoplankton communities also differed vertically. Pelagophytes occurred in higher abundance in subsurface water, while dinoflagellates reached greater concentrations in near-surface waters.

New evidence for the West Florida Shelf Plume

The occurrence of an episodic chlorophyll plume detected on the West Florida Shelf between 1979 and 1986 was confirmed in March 1995 with shipboard data and in March 1998 with new ocean color data from the SeaWiFS sensor. New evidence is presented to support the hypothesis that diatom blooms off Apalachicola Bay are the precursor of the seasonal West Florida Shelf plume, and that the nutrient requirements for such blooms, especially silicate, can be supported by river discharge. The observations indicate that the impact of rivers is maximal over the middle shelf and decreases over the outer shelf. Salinity and discharge measurements support the concept that the Apalachicola River had a major impact at distances exceeding 100 km from the coast and that it plays an important role in the formation of offshore blooms. Preliminary analyses suggest that successional processes lead to cryptophytes dominating in the offshore blooms.