Two taxa of Taxodium, bald cypress and pond cypress, occur in the south-eastern United States. The ranges of these taxa overlap in the south-eastern Coastal Plain, with the range of the latter being more restricted. Although these taxa co-occur throughout a portion of the more expansive range of bald cypress (Taxodium distichum (L.) L. C. Rich), the habitats of the two taxa appear to di er. Consequently, considerable debate has occurred regarding the taxonomic status of pond cypress. Some authors recognize pond cypress as a distinct species (Taxodium ascendens Brongn.), whereas others recognize it as a variety/ecotype (Taxodium distichum var. imbricarium (Nutt.) Croom). In this study, the genetic diversity of these two taxa was investigated using 10 DNA markers based on sequences from cDNA clones of Cryptomeria japonica. Cryptomeria is a monospeci®c genus native to Japan, and is a close relative of Taxodium. These markers were codominant in Cryptomeria and were presumed to be codominant in Taxodium. DNA was extracted from leaf tissue collected from six populations of bald cypress and seven populations of pond cypress throughout Florida and Georgia. The average heterozygosities of bald cypress and pond cypress were 0.386 (SE 0.040) and 0.380 (SE 0.040), respectively. Most of the genetic variation (91.9%) was found within populations, 4.9% was found between populations and 3.2% between taxa. Results of DNA analysis using cleaved ampli®ed polymorphic sequences (CAPS) in this study did not suggest that pond cypress was a species distinct from bald cypress. Our conclusion is that the two taxa of Taxodium should be given varietal status.Keywords: bald cypress, CAPS, Cryptomeria, pond cypress, STS, Taxodium. IntroductionFossil records suggest that Taxodium was widely distributed throughout North America, Europe, and East Asia from the Cretaceous to the Pleistocene (Small, 1931; Florin, 1963). As the Pleistocene seas receded, Taxodium settled into its present distribution in the south-eastern United States and Mexico. Two taxa, bald cypress and pond cypress, occur in the south-eastern United States. The ranges of these taxa overlap in the south-eastern Coastal Plain, with the range of the latter being more restricted.The taxonomic status of Taxodium has been debated since the early 19th century (Watson, 1985). Britton (1926), Dallimore & Jackson (1966) and Rehder (1940) recognized three species: T. distichum (L.) L. C. Rich. (bald cypress), T. ascendens Brongn. (pond cypress) and T. mucronatum Ten. (Montezuma bald cypress). Godfrey (1988) concurred with this taxonomic treatment of pond cypress and bald cypress, suggesting temporal di erences in phenology.Watson (1983, 1985) evaluated morphological, anatomical, biochemical and cytological aspects of pond cypress and bald cypress, and concluded that the di erences between them for the characteristics he considered were minor. He suggested that pond cypress be considered as a variety of bald cypress (T. distichum In molecular phylogenetic studies, no di erences wer...

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In theory, "aquifer storage and recovery" (ASR) is a form of artificial aquifer recharge consisting of three components: (1) aquifer injections of fluids; (2) withdrawals of the injected fluids; and (3) a period of time between the injections and withdrawals that is considered to be aquifer "storage" of the injected fluids. The injected fluids may be: (1) treated sewage effluent (also known as reclaimed, reuse, or bright water); (2) stormwater runoff pumped out of canals, mine pits or other areas; (3) surface waters from natural lakes and streams; or (4) ground water from different aquifer zones. An evaluation of existing data from more than 80 injection/withdrawal cycle tests at 18 ASR sites in 9 counties throughout southern Florida, in the regional karst Floridan aquifer system of the United States (US) revealed that less than 25% actual "recovery" was achieved from ASR wells where water from various sources was injected into the regional karst aquifer system. Determination of actual "recovery" was based on the reported chloride content of injected and recovered water and was more suggestive of fluid disposal than aquifer "recharge." Actual "recovery" for those ASR tests, adjusted to the chloride concentrations of injected fluids, ranged from 0-17% for "storage" periods that ranged from 0-181 days. Although results of actual "recovery" provide little support for the concept of "stored" water, in reality those results also overestimate the volume of injected water that is stored because it assumes that water recovered at the same chloride concentration is the same water that was injected. There is no evidence in the ASR data to support that assumption. The low actual "recovery" rates occurred despite the fact that 28 of the cycle tests had a "storage" period < 1 day and the longest "storage" period tested did not exceed 181 days. Those brief "storage" periods also were insufficient to meet the stated agency objectives of retrieving the injected fluids during the dry season, more than six months after injection of what is termed "excess water" during the rainy season. Despite those results, the agency's Final Technical Data Report (TDR) and groundwater model released in 2014 concluded that: (1) "recovery" from those wells would range from 70-100% and (2) 232 ASR wells (94 in the upper Floridan aquifer, 37 in the Avon Park Permeable Zone of the middle Florida aquifer and 101 in the Boulder Zone) could be completed in Florida's Greater Everglades Basin (basin) as restoration. That Final TDR did not consider differences in chloride content between water that was injected into and withdrawn from the ASR cycle tests and that groundwater model for the basin did not include the anisotropy option or preferential flow through karst conduits such as fractures. Preferential flow of water injected and withdrawn could result in both low ASR "recovery" rates and environmental harm, such as submarine groundwater discharge (SGD) contaminated with pollutants, including nutrients that result in harmful algal blooms (HABs). That TD...

Abstract:Pond-cypress (Taxodium ascendens Brong.) is a dominant canopy species in depressional wetlands of the south-eastern Coastal Plain. Unsustainable withdrawals from the karst Floridan aquifer system have caused premature decline and death of pond-cypress trees, presumably owing to altered hydroperiods (which alter the flow of water and nutrients in trees). There has been no scientifically based means to determine sustainable yield from this regional aquifer system or to detect early stages of physical/ecological damage associated with groundwater mining and aquifer storage and recovery (ASR, which also can alter natural hydroperiods). In this study, the relationship between visual symptoms (indicators) of stress or premature decline, and spectral reflectance was evaluated using dried, milled branch tips collected from natural stands of mature pond-cypress. Depressional systems evaluated represented four of the six aquifer system subregions where subsurface perturbations from groundwater mining: (i) were presumed not to be occurring (reference wetlands); (ii) may be occurring but are not documented; and (iii) have been confirmed. Sampled trees were assigned to one of three stress classes (1, no/minimal; 2, moderate; 3, severe) based on the visual indicators. Partial least squares-linear discriminant analysis of second derivative spectral transformations in the visible/shortwave near-infrared (NIR) region (400-1100 nm) and the NIR region (1100-2500 nm) was used to evaluate the samples in assigned classes.Class 1 samples were discriminated from combined class 2 and 3 samples in the NIR region with 100% and 97% accuracy for consecutive winter sample periods (before bud-break). The percentage of correctly classified samples in this spectral region was lower (85%) for summer samples (full leaf-out). Second-derivative models for the NIR region developed from the winter data sets predicted assigned classes for alternate winter's samples with an accuracy of 97% and 100%. High correlation between spectral reflectance of dried, milled branch tips collected from mature pond-cypress in winter and visual indicators of premature decline suggests in situ pond-cypress are hydroecological indicators of anthropogenic subsurface hydroperiod perturbations. This approach provides objective means for early detection of unsustainable aquifer yield and adverse impacts from ASR activities in the south-eastern Coastal Plain. Used in conjunction with hydrological monitoring and modelling, the hydroecological indicators should provide the means with which sustainable yield in the south-eastern Coastal Plain can be achieved and maintained.

Sustainable development of any type that utilizes water or involves excavations in karst aquifer systems, such as the regional Floridan aquifer system (FAS), requires knowledge of preferential groundwater flow pathways that can extend adverse impacts beyond the development site and alter natural hydroperiods. Such pathways include fractures and other types of karst conduits that are associated with modern and relict sinkholes. Developments, including power plants and mines, that have not accounted for these features have caused induced recharge, altered hydroperiods and saltwater intrusion in the FAS, resulting in destruction of wetlands and adverse impacts to other surface waters, wildlife habitat and threatened and endangered species. This study analyzed indicators of preferential groundwater flow by considering surface expressions of underlying geological conditions (lineaments and modern sinkholes) in the FAS, which coincide with the United States southeastern coastal plain. Lineament mapping by Vernon (1951) and the Florida Department of Transportation (FDOT, 1973), incorporating analog mapping techniques and hardcopy prints of satellite imagery, preceded extensive urbanization, groundwater extractions, and mining in the region. All of these alterations limit the ability to identify fractures using lineaments by reducing groundwater discharges and vegetation indicative of those discharges. In this study, established methods for georectification, including control-point identification and spatial matching of scanned maps and remotely sensed images, were applied to these previously mapped lineaments. These results were applied to the environmentally sensitive karst study area of Citrus and Levy Counties, Florida in the southern extent of the FAS. Geospatial analyses of lineament distribution and modern sinkhole locations from the state database showed a dense network of lineaments with associated sinkholes throughout the study area and seven surrounding counties, including the proposed sites for a nuclear power plant and two mines in Levy County. Proposed excavations and water use for construction and operation of the power plant and mines would result in irreversible adverse environmental impacts on extensive depressional wetlands beyond the surface-footprint impact of these developments via these preferential flow pathways that were not evaluated during the review process.