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The Cretaceous lower Nanaimo Group in the Georgia Basin, Canada comprises multiple depositional phases with distinct depocentres that accumulated in a tectonically active forearc basin setting. Basal coarse-clastic strata are preserved in paleotopographic depressions and grade upwards into coal-bearing coastal plains and shallow-marine deposits. Coal-bearing and shallow-marine strata grade laterally into and are overlain by, regionally extensive mudstones and turbidites deposited in deep water. A glauconitic sandstone bed within the deep-water strata is interpreted as a condensed section and underlies a major disconformity that developed during a pause in the deposition of the lower Nanaimo Group. A second major coarse-clastic succession occurs hundreds of metres above the glauconite bed in the central Georgia Basin and comprises conglomerate, sandstone, mudstone and coal deposited in continental depositional environments. The shift in sedimentation from the northern Georgia Basin to the central Georgia Basin is interpreted to record the emergence of an island (Nanoose Uplift) in the central Georgia Basin that acted as a major sediment source to the adjacent depocentres. The stratigraphic break between the coal-bearing coarse-clastic strata in the northern Georgia Basin and the significantly younger coal-bearing coarse-clastic strata in the central Georgia Basin indicates that the lower Nanaimo Group was deposited in distinct depocentres. Between the older, coarse-clastic strata in the north and younger, coarse-clastic strata in the central Georgia Basin, we hypothesize that a major deepwater canyon system (Qualicum Canyon) existed and transferred sediment from the semi-restricted Georgia Basin to the Pacific Ocean to the west. Development of the Qualicum Canyon and exposure of the Nanoose Uplift during deposition of the younger, central coarse-clastic strata suggests that syntectonic activity drove basin uplift and erosion and this occurred throughout the deposition of the lower Nanaimo Group. [ABSTRACT FROM AUTHOR]

The genus Castanea, divided into seven extant species of trees worldwide, includes the American chestnut, C. dentata. This once common North American tree has been nearly eliminated from the landscape due to the appearance of chestnut blight early in the Twentieth Century. Castanea has a long history as a component of palynological assemblages, though megafossil paleobotanical remains are quite rare. The distributions of what are believed to be Castanea pollen as they have been derived from coastal plain and near-shore sediments dating back to the Neogene of the coastal plain of the southeastern US are discussed. The abundances of Castanea pollen in microfossil preparations are carefully considered relative to the concept of 'pollen sum' and while it appears that the trees were quite abundant as components of coastal woodlands during the Neogene, the actual number of pollen we found in samples is quite low. American chestnut trees continued to be important into the late Pleistocene and through the time when humans first occupied both coastal and inland areas of the southeastern US. [ABSTRACT FROM AUTHOR]

We inventoried the robber fly (Family Asilidae) fauna of 2 distinct Pinus palustris (Longleaf Pine) habitat types (mesic pine flatwoods, xeric sandhills) on a large, fire-managed landscape (Fort Stewart) located in the Coastal Plain of southeastern Georgia. We conducted aerial-net and sweep-net surveys at 30 sites on 111 dates from October 2020 to November 2022. We also sampled hardwood and mixed pine-hardwood communities. We collected a total of 380 robber flies comprising 25 genera and 62 species. We recorded 47 species from Longleaf Pine habitats, with 42 species collected from xeric Longleaf Pine sandhills and 20 species from mesic Longleaf Pine flatwoods. Thirty-two species were found in hardwood habitats. Machimus polyphemi, a poorly known obligate commensal of Gopherus polyphemus (Gopher Tortoise) burrows, was found at 5 sites. Two species that we documented from xeric Longleaf Pine sandhills, Machimus blantoni and Efferia slossonae, represent the first state records for Georgia. An Echthodopa cf. formosa population found in mesic pine flatwoods represents a significant range extension. Also, we report Stichopogon abdominalis from Georgia for the first time. [ABSTRACT FROM AUTHOR]

Tidal point bars are commonly developed in coastal plain meandering channels. They form by the same basic processes as fluvial point bars but are further modified by tidal action. This study analyses the sedimentary facies of six active tidal point bars and their relationships. The bars are situated along the Georgia coastal plain, USA, in the lower and upper reaches of the fluvial marine transition and in tidal channels without upstream river input. Based on millimetric logging of 31 cores, nine sedimentary facies were identified, which are proposed to be used for the characterization of tidal point bars in other depositional settings. These bars share common sedimentary facies; however, the internal organization of these facies and their associations differ appreciably in response to complex local tidal processes and fluvial–tidal interactions. The increase in tidal influence results in prominent heterogeneous architectures, with greater concentration of heterolithic stratification (mostly inclined), bioturbation and evidence of flow reversals. In contrast, when freshwater river discharge overcomes tidal stages in the fluvial marine transition bars, structureless coarse‐grained facies with attendant erosional surfaces and decreased bioturbation are predominantly developed. In the lower reach of the fluvial marine transition, along the estuarine turbidity maximum, alternations of fluvial and tidal sedimentation are evidenced by a bimodal facies association, where alternations of gravel lag and muddy facies (massive to heterolithic) dominate. Moreover, despite differences in local hydrodynamics, coarsening‐upward sequences, mostly composed of structureless coarser facies, are consistently distributed along the upper parts of the bars, which may indicate overprinting of regional events such as storm surge‐related floodings in the sedimentological record. This study provides a basis for better identifying the hydrodynamic processes that shape coastal systems, such as estuarine and backbarrier environments. Additionally, those deposits are analogues for certain hydrocarbon reservoirs, thereby increasing knowledge of their facies distribution and aiding production optimization. [ABSTRACT FROM AUTHOR]

In fields of the coastal plain of Georgia (USA), the seed bug, Neacoryphus bicrucis, feeds and mates exclusively on ragwort. The distribution of ragwort, Senecio tomentosus, is either dispersed, with small numbers of plants spread over large areas, or clustered, with large numbers of plants concentrated into relatively small areas. In dispersed habitat, the density of seed bugs is always low (< 20/0.25 m2) as is the proportion of adults who are mating (20%). In clustered habitat, adult densities are occasionally high (30–75/0.25 m2) as are mating rates (> 67%). In both habitats, mating males are in better condition (= mass – mass expected from length) than non-mating males. In clustered habitats, aggression between males occurs frequently and determines residency in areas of high ragwort abundance to which females are especially attracted for mating and oviposition. A mark-recapture study revealed that males move about more in dispersed than clustered habitats, possibly searching for mates. Variance in male mating efficiency (copulations/sightings) matches random expectations in dispersed habitats but is significantly higher than that in clustered habitats, suggesting greater opportunity for sexual selection. A multivariate analysis of selection intensity using mark-recapture data revealed that longer wings and shorter bodies are favored in dispersed habitat, suggesting selection on ability to search for mates. In clustered habitat, selection favors a longer body, antennae, and legs. This finding suggests selection favoring dominance in aggressive interactions, as legs and antennae are used to grapple with opponents and to seize females during aggressive courtship. [ABSTRACT FROM AUTHOR]

Gymnoscirtetes is endemic to the southeastern portion of the North American Coastal Plain and previously comprised two species: G. pusillus Scudder, 1897 and G. morsei Hebard, 1918. Here, this genus is revised based on male genital morphology and geographic data, and four new species are described: G. georgiaensis sp. nov., G. pageae sp. nov., G. rex sp. nov., and G. wadeorum sp. nov. Gymnoscirtetes is primarily associated with mesic grasslands such as pitcher plant bogs, flatwoods, and the edges of seasonal ponds, but can be found less commonly in a variety of other grasslands. [ABSTRACT FROM AUTHOR]

Pecan (Carya illinoinensis) orchards in Georgia and throughout the southeastern United States are commonly established from land that had previously been used for row cropping systems. Soil quality is characteristically low in the loamy-sand, low pH soils of the southeastern Coastal Plain. Changes in land use are known to exhibit different effects on soil quality; however, no studies specifically address soil enhancement from converting row crop land to pecan orchards in this region. Sampling was conducted in eight counties throughout the coastal plain of South Georgia in 2020 and 2021. The objectives of this study were to analyze and compare soil quality indicators of pecan orchards of varying ages and adjacent row crop fields. Soil quality indicators analyzed include soil organic matter (SOM), active carbon or permanganate oxidizable carbon (POXC), aggregate stability, cation exchange capacity (CEC), bulk density, porosity, Solvita CO2-Burst, SLAN (Solvita labile-amino nitrogen), pH, and total N. Results from this study demonstrate that pecan orchards under commercial management had higher soil quality compared with row crop fields based on the indicators measured. Active carbon and Solvita CO2-Burst measurements suggest that pecan orchards exhibited significantly higher rates of microbial activity and soil respiration. Indicators of soil microbial activity such as active carbon and Solvita CO2-Burst were strongly correlated with SOM, which explained much of the variation observed in these measurements of soil microbial activity. Selected soil quality indicators also provide evidence that the soil quality of commercial pecan orchards in this region improves with orchard age. [ABSTRACT FROM AUTHOR]

Myotis austroriparius (Southeastern Myotis) traditionally inhabit bottomland hardwood forests along the Atlantic coastal plain and lower Mississippi River Valley. This insectivorous bat is a species of conservation concern in Alabama and Georgia and was thought to be restricted to the Southern Coastal Plain and Southeastern Plains ecoregions. Based primarily on cave, transportation-structure, and mist-netting surveys, we documented occurrences of Southeastern Myotis in 14 Alabama and 20 Georgia counties outside and along the border of the accepted range, including in the Piedmont, Ridge and Valley, Interior Plateau, and Southwestern Appalachians ecoregions. We reviewed observations of bats year-round in both states, including pregnant and lactating females and winter hibernacula. Roosting sites included caves, culverts, bridges, and tree cavities. Combined, these observations provide strong evidence that the range of Southeastern Myotis should consist of all Alabama and Georgia except for the Blue Ridge ecoregion. This increase in distribution may result from increased surveying efforts and/or range expansion due to climate change, as observed in other southeastern bat species. [ABSTRACT FROM AUTHOR]

We examined geographic and racial variation in cancer mortality within the state of Georgia, and investigated the correlation between the observed spatial differences and county-level characteristics. We analyzed county-level cancer mortality data collected by the Centers for Disease Control and Prevention on breast, colorectal, lung, and prostate cancer mortality among adults (aged ≥ 18 years) in 159 Georgia counties from years 1999 through 2019. Geospatial methods were applied, and we identified hot spot counties based on cancer mortality rates overall and stratified by non-Hispanic white (NH-white) and NH-black race/ethnicity. Among all adults, 5.0% (8 of 159), 8.2% (13 of 159), 5.0% (8 of 159), and 6.9% (11 of 159) of Georgia counties were estimated hot spots for breast cancer, colorectal, lung, and prostate cancer mortality, respectively. Cancer mortality hot spots were heavily concentrated in three major areas: (1) eastern Piedmont to Coastal Plain regions, (2) southwestern rural Georgia area, or (3) northern-most rural Georgia. Overall, hot spot counties generally had higher proportion of NH-black adults, older adult population, greater poverty, and more rurality. In Georgia, targeted cancer prevention strategies and allocation of health resources are needed in counties with elevated cancer mortality rates, focusing on interventions suitable for NH-black race/ethnicity, low-income, and rural residents. [ABSTRACT FROM AUTHOR]

Loblolly pine (Pinus taeda L.) productivity over the past century has increased significantly from genetic improvements and more intensive management practices. The current study concludes a series of assessments of loblolly pine growth/physiological responses to continuous resource management treatments of weed control (W), weed control plus irrigation (WI), and weed control plus irrigation and fertigation (WIF). Increment cores were analyzed by X-ray densitometry to assess treatment impacts on wood properties. Plotting the wood property data against assigned years allowed results to be compared with available weather data. Mean values for all wood property determinations were similar between the W and WI treatments. Increased ring width for the WIF treatment was consistent with other studies demonstrating substantial increases in loblolly pine productivity by fertilization. Since decreases in ring specific gravity (SG) from fertilization can be offset by increases in ring SG from irrigation, gains in productivity were achieved without reducing wood quality. [ABSTRACT FROM AUTHOR]

Rare-earth elements (REE) are critical minerals that are indispensable for high-tech products and technologies. Significant efforts have been focused on the exploration and identification of new and domestic reserves of REE. This study reports geochemical and mineralogical occurrences of accumulated REE with significant fractions of ion-adsorption clays (IAC) within bauxite-kaolin ore, hosted within sedimentary strata. This deposit type can be found throughout portions of Georgia and eastern Alabama (USA) in the Southeast Upper Coastal Plain. These deposits were developed by high degrees of chemical weathering of older, kaolinite-rich sedimentary strata. Several major changes in whole rock mineralogy and geochemistry occurred, leading to the development of zones of REE depletion, fractionation, and accumulation. Depletions of REE in the bauxite zone were significant, with whole rock contents of ∼50% ΣREE relative to average upper continental crust (UCC). Fractionated REE were observed by low La/Yb N values (La/Yb N = 0.2) due to depletion in LREE (<40% UCC) with concomitant HREE retention (∼1.1–1.3 times UCC). Strongly positive Ce/Ce* anomalies (Ce/Ce* = 1.3), very low ion-exchangeable Ce contents (Ce/LREE = 0.1), and low solubility of Ce (0.9–1.2%) under reducing conditions compared to all other LREE (4.5–9.9%) were further observed. These characteristics were strong indications of REE fractionation that occurred during formation of the bauxite zone. Underlying the bauxite zone, accumulations of the remobilized REE were substantial. At the base of the lower kaolin zone, elevated ion-exchangeable REE contents were notable (11–33% for total REE), and more specifically 11–12% for LREE, ∼28% for ΣTb-Lu, and ∼ 33% for Y. The elevated ion-exchangeable contents coincided with whole rock contents that were ∼ 250% ΣREE relative to UCC. These REE accumulations occurred within organic-rich strata at the base of the section. This setting represents a significant difference relative to the REE accumulations in profiles for the granite-regolith deposit type. These findings highlighted the movement of dissolved REE, accumulation as sorbed species, as well as the potential role that organic ligands play during REE precipitation and sorption processes. These results permit consideration for further research into REE occurrences in clay deposits of sedimentary origin, which have been underexplored compared to granite-regolith REE deposits. [Display omitted] • The bauxite-kaolin deposit contains accumulated REE and ion-adsorption clays. • Bauxite zones were REE depleted and fractionated with positive Ce/Ce* anomalies. • Lower zones contained elevated whole rock and ion-exchangeable REE. • Differences were noted between bauxite-kaolin and granite-regolith deposits. • These sedimentary-hosted REE are potentially a new deposit model for REE. [ABSTRACT FROM AUTHOR]

Coarse woody debris (CWD) addition is a restoration technique that has been used to reduce effects of landscape disturbance on instream habitat. However, efficacy of this technique for improving ecosystem condition is not well established, in part because monitoring designed to evaluate long-term efficacy is rare. We assessed the effectiveness of CWD additions in disturbed Coastal Plain streams at Fort Benning Military Installation, Georgia, USA, 14 y after initial restoration. In October 2003, 4 disturbed streams received CWD additions (restored streams), and 4 streams were left as unrestored controls. Pre-restoration (2001–2003) and post-restoration (2003–2006) monitoring of nutrient uptake, stream metabolism, and water-quality variables revealed 1) minimal change in water-quality variables, 2) increased stream metabolism and nutrient-uptake rates immediately following restoration, and 3) decreased metabolism and uptake over the remainder of the 3-y post-restoration period. We returned to these streams in 2017 and 2018, measured the same variables, and found minimal long-term effects of restoration on water quality, nutrient uptake, and whole-stream metabolism indicators; however, streamwater pH decreased in all streams 14 y after restoration, and there was a weak treatment × period interaction, indicating that CWD additions may decrease pH in the long term. Further, we found few relationships between watershed disturbance and water-quality variables and ecosystem function metrics, although some relationships were apparent during certain seasons and years. Our study is one of the few that have assessed the long-term effects of CWD additions, or any other stream-restoration technique, on ecosystem function. These long-term assessments may be necessary to determine if restorations are a good use of limited resources. [ABSTRACT FROM AUTHOR]

Brassica carinata (carinata), a non‐food oilseed feedstock mainly used for biofuel, is a relatively new alternative winter crop in the southeastern (SE) United States (US). However, there are limited N rate and N application timing data available at the regional scale. These data are needed to expand production in the SE US. An N rate study was conducted during the winter–spring growing seasons during 2017–2018 and 2018–2019 in Florida, US, and at three locations during 2018–2019 in Georgia, US, to quantify the effects of N rate (0, 45, 90, 134, and 179 kg N ha−1) on carinata nutrient uptake, biomass, seed yield, and seed chemical composition. Seed yield showed a linear response up to 134 kg N ha−1. Seed protein and glucosinolate concentrations decreased from 0 to 90 kg N ha−1, then increased from 90 to 179 kg N ha−1. Seed oil concentration was inversely related to seed protein concentration. A two‐factor N application timing study (4 N application timing: at‐plant, pre‐bolting, at‐plant + pre‐bolting, at‐plant + pre‐bolting + bolting × 4 N rates: 0, 45, 90, and 134 kg N ha−1) was conducted in Georgia, US, over three site‐years to quantify the effect of N application timing on yield and agronomic and economic optimum N rates (AONR and EONR, respectively). All split applications increased AONR by at least 10 kg N ha−1 compared to a single at‐plant application. A two‐split N application was more profitable than either a single N application or a three‐split N application based on marginal return. A two‐way split application (at‐plant + pre‐bolting) at 134 kg N ha−1 is recommended to optimize yield and economical production. Based on uncertainty analyses, the 50% credible interval of EONR occurred between 116 and 152 kg N ha−1, with a median estimate at 130 kg N ha−1. [ABSTRACT FROM AUTHOR]

Little is known about the nesting habits of Drymarchon couperi (Eastern Indigo Snake), a federally threatened species native to the Coastal Plain of the southeastern United States. Here, we describe locations of nest sites based on reports in the literature and from our field observations of putative nests and hatched eggshells. All wild nest sites (n = 7) known for the species (i.e., excluding those from translocated and/or captive-bred snakes) have been found in xeric sandhill habitats in southern Georgia and all have been associated with Gopherus polyphemus (Gopher Tortoise) burrows, including in the sand of burrow aprons. To protect snake nests, buffers around tortoise burrows are highly recommended during all habitat management activities (e.g., selective thinning, Pinus palustris [Longleaf Pine] restoration). [ABSTRACT FROM AUTHOR]

Carinata (Brassica carinata) is an industrial oilseed feedstock for renewable fuels grown as a winter crop in the southeast US, which may provide a new rotation alternative and benefits for water quality. However, the effects of carinata on water quantity and quality at the watershed and local scales are unknown. In this study, we use the Soil and Water Assessment Tool (SWAT) to assess the potential influence of carinata on water balance components, nutrients and sediment loads under plausible future scenarios of land use change in the upper Suwannee River Basin in the Atlantic Coastal Plain Physiographic Region near Tifton in South‐Central Georgia. Three future scenarios are considered, including planting stand‐alone carinata in winter fallow land every third year, planting stand‐alone winter wheat in winter fallow land every third year, and carinata and winter wheat in rotation, one year of winter carinata followed by two years of winter wheat during simulation periods. The results show that under all three future scenarios, surface runoff, sediment, phosphorus, and nitrogen loadings decrease at both watershed and local scales, with higher average monthly reductions in the stand‐alone carinata scenario versus the stand‐alone winter wheat scenario. When carinata and winter wheat were planted over 36% of the total watershed area, reduction in total sediment, mineral phosphorus, and nitrate loads was ranging from 11.5% to 50.0%. However, when only 12% of the total watershed area was converted to carinata, the simulated reductions ranged from 3.8% to 14.0%. This suggests that the extent of carinata planting is crucial in assessing its hydrologic and water quality benefits. Overall, these results indicate that planting the biofuel carinata as a winter crop can reduce sediment and nutrient loading and provide water quality benefits to downstream waterbodies. [ABSTRACT FROM AUTHOR]

During the course of surveys for freshwater amphibians/reptiles in the Coastal Plain of southeastern Georgia and northern Florida, we documented parasitism of the Amphiuma means (Two-toed Amphiuma) by the leech Macrobdella ditetra (Family Macrobdellidae). We observed this leech on Two-toed Amphiumas at 4 different wetland sites, with 1–3 individual M. ditetra present on 6 of 16 (37.5%) Two-toed Amphiumas captured via aquatic trapping. Leeches were not found on Siren lacertina (Greater Siren; n = 10), a second large, eel-like salamander inhabiting some of the same wetlands. We did not document Philobdella floridana, a second macrobdellid leech species often found syntopically with M. ditetra, feeding on the Two-toed Amphiuma. [ABSTRACT FROM AUTHOR]

Aquatic macroinvertebrates are often the subject of biomonitoring efforts because they are ubiquitous in most systems and are known to be suitable indicators of water quality. The vast majority of biomonitoring efforts that use macroinvertebrates are tailored towards small, wadeable streams, whereas methods for sampling macroinvertebrates in non-wadeable streams (i.e., large rivers) are often less available. We compared the use of a wood sampler to collect aquatic macroinvertebrates with two more commonly used samplers (Hester-Dendy and leaf packs) to assess its suitability for sampling non-wadeable systems in the Georgia Coastal Plain. All three types of samplers were deployed at three sites on each of the Savannah and Ogeechee River for approximately 30 days during the fall of 2014. Mean, standard deviation, and variance components were examined from 53 common bioassessment metrics and 2 multi-metric indices to assess for potential differences in colonizing macroinvertebrates between the samplers. Only 9 of the metrics examined scored significantly different between sampling devices, however, assemblages colonizing the three sampling devices differed (PERMANOVA; F14,37 =1.6078, P = 0.001). Results suggest assemblage differences were primarily driven by the proportions of taxa collected by each device, rather than by different taxa colonizing devices altogether. Estimates of variance components attributed a large percentage (i.e., >20%) of the variability encountered to differences between sites, rather than devices. Our study shows that wood samplers are comparable to other devices commonly used for collecting macroinvertebrates from non-wadeable streams in the Georgia Coastal Plain. Furthermore, wood samplers can provide a suitable alternative for bioassessment, although some differences in the proportions of taxa collected with alternative devices should be expected. Determining the precision and overall efficiency of alternative sampling devices is an important step towards developing standard operating procedures for the bioassessment of large coastal plain rivers. [ABSTRACT FROM AUTHOR]

Understanding how past communities have been shaped by environmental alterations can provide insight into the impacts of future climate change. Local climate and river systems have changed significantly over the last glacial maximum, but little is known about the communities of the Georgian Coastal Plain earlier in the period. Plant fossils from Coffee Bluff, a Quaternary organic river deposit of the Ocmulgee River in southeastern Georgia, were used to determine past environmental and climatic conditions. The paleoflora were found imbedded in a mud matrix and were removed by a slaking method; they were later identified and separated to respective ecological environments. Of the eleven species identified, one was a wetland species (marsh sedges), while the remaining ten were woodland species. From using the coexistence approach with the plant fossils and aligning their growing conditions, we suggest that Coffee Bluff was a stream/riverine habitat with loamy and well-drained soils; local climate was humid, with temperatures and annual precipitation ranging from 10 to 210C and 1016 to 1524 mm, respectively. Few gymnosperm specimens were recovered in the material, though groups like conifers were dominant in the coastal plain environment during the late Pleistocene. It is most likely that there were fewer conifer trees near the collection area. [ABSTRACT FROM AUTHOR]

The elemental composition of soil plays an essential role in crop nutrition, but losses from croplands can negatively impact soil fertility and water quality. We compared the impact of strip tillage (ST) and conventional tillage (CT) on element concentrations and loads in surface runoff and subsurface flow from plots under rotational cotton (Gossypium hirsutum L.) and peanut (Arachis hypogaea L.) production with winter cover cropping. Total element concentrations (calcium [Ca], iron [Fe], potassium [K], magnesium [Mg], manganese [Mn], sodium [Na], phosphorus [P], sulfur [S], silicon [Si], and zinc [Zn]) in surface runoff and subsurface flow samples were measured using Inductively Coupled Plasma with Optical Emission Spectroscopy (ICP-OES). Element loads were estimated by multiplying the element concentrations by the surface runoff and drainage volumes. Significantly greater (p = 0.05) surface runoff loads for all elements (with the exception of K and Zn) were observed from the CT compared with the ST treatment plots only in 2006, likely due to the combined effects of hydrology and the timing of gypsum amendments that year. Surface runoff was the primary hydrologic pathway for Fe, K, Mn, P, Si, and Zn loss while subsurface flow was the primary hydrologic pathway for Ca, Mg, and S loss with both tillage treatments. Lower concentrations of Ca, Mg, Na, and S in the subsurface flow with ST compared to CT suggest that this tillage practice, in conjunction with the proper timing of fertilizer and soil amendment applications (e.g., poultry litter and gypsum) can be an effective method for reducing element losses from croplands. This finding highlights the importance of conservation practices in sustaining healthy cropland soils while reducing element losses and associated environmental impacts. [ABSTRACT FROM AUTHOR]

Despite efforts to improve water quality in US watersheds, recent assessments of water quality trends in these watersheds indicate concentrations of nitrogen (N) and phosphorus (P) show minimal changes in the majority of studied streams across the nation. Moreover, results of the US Geological Survey (USGS) National Water-Quality Assessment (NAWQA) indicate that nutrient concentrations in streams and groundwater in basins with significant agriculture or urban development are substantially greater than naturally occurring or background levels. Long-term hydrologic and water quality data from watersheds are a key component to building an understanding that will dictate what and where changes in watershed management need to be made to achieve improvements in water quality. Forty-one years of hydrologic and water quality data from the Little River Experimental Watershed (LREW) were assembled to evaluate trends in streamflow quantity and quality from the LREW and relationships to changes in land cover and management. Concentrations and loads of chloride (Cl), ammonium-N (NH4-N), nitrate plus nitrite-N (NO3-N), total kjeldahl N (TKN), total P (TP), and dissolved molybdate reactive P (DMRP) from 1974 to 2014 were determined. In general, concentrations of N and P have remained low and stable, with some increases observed from 1980 to 1999. In contrast, Cl concentration appears to be steadily increasing, possibly due to increased fertilization in the LREW. Flow-weighted mean concentrations were 0.21 mg L-1 y-1 for NO3-N, 0.08 mg L-1 y-1 for NH4-N, 1.41 mg L-1 y-1 for TKN, 9.30 mg L-1 y-1 for Cl, 0.15 mg L-1 y-1 for TP, and 0.03 mg L-1 y-1 for DMRP. Average annual loads were 0.64 kg ha-1 y-1 for NO3-N, 0.25 kg ha-1 y-1 for NH4-N, 4.47 kg ha-1 y-1 for TKN, 29.54 kg ha-1 y-1 for Cl, 0.46 kg ha-1 y-1 for TP, and 0.10 kg ha-1 y-1 for DMRP. The low nutrient loading in the watershed is attributed to the dense riparian buffers within the LREW, which have been shown to be effective for reducing N loading to the stream. Due to (1) small variations in nutrient concentrations and loads, (2) large variability in precipitation, (3) large variability in streamflow, and (4) small variations in land cover, no clear relationships among changes in land cover and management and nutrient loads were found. Loading rates of N and P, although somewhat influenced by changes in concentration, are largely dictated by changes in streamflow volume in the LREW. [ABSTRACT FROM AUTHOR]

Previous phylogenetic studies of the grape downy mildew pathogen, Plasmopara viticola, revealed five cryptic species in eastern North America that differed in their host range and geographic distribution. Preliminary comparative studies also documented differences in temperature responses during infection between certain cryptic species, indicating the biological relevance of knowing which cryptic species of the pathogen are present in a given region. However, limited information is available regarding the presence, prevalence and dynamics of cryptic species of P. viticola in the southeastern United States. Here, 301 P. viticola isolates obtained from cultivated grape species in five distinct grape‐growing regions of Georgia and Florida were subjected to cleaved amplified polymorphic sequence analysis and multilocus sequencing (internal transcribed spacer region of the rDNA, actin and β‐tubulin) to identify cryptic species and infer phylogenetic relationships. Three cryptic species, P. viticola clade aestivalis (Pva), clade vinifera (Pvv) and clade vulpina (Pvu), were identified in Georgia, whereas two, Pva and Pvv, were found in Florida; all three cryptic species are reported here for the first time in Georgia, whereas Pva is reported for the first time in Florida. Pva was the most prevalent cryptic species (72.1% of isolates) and was distributed widely from the North Georgia Mountains to Mid‐Florida, whereas Pvv (27.2%) and Pvu (0.7%) were found only in the Coastal Plain region of the two states. Interestingly, Pvu was obtained from French American hybrid Blanc du Bois and could be subcultured on Vitis vinifera Chardonnay, suggesting a broader host range than only the wild species Vitis vulpina reported previously. [ABSTRACT FROM AUTHOR]

Curculionidae (weevils) frequently are recognized as favoring moist environments and wetland vegetation. To better understand the relationship between wetland type and the presence of curculionid species, twenty-four isolated wetlands (previously characterized as marshes, savannas or forested swamps) were sampled. Seventeen genera and 27 species were identified. Indicator species analysis revealed an association between the genus Dirabius and marsh habitat. NMS (Non-Metric Multidimensional Scaling Ordination) found a significant 2-dimensional solution to abundance data. Auleutes nebulosus, Lissorhoptrus simplex, Notiodes laticollis, Rhinoncus longulus, Sphenophorus minimus, and an unidentified species of Dirabius and Listronotus were associated with marshes. Swamps were characterized by their absence of Curculionidae. Savannas were intermediate between marshes and swamps. Marshes, with their diversity of vascular plants, appear to provide more suitable habitat and possess characteristics that allow curculionid populations to persist in the landscape. [ABSTRACT FROM AUTHOR]

Highlights: [•] Anopheles quadrimaculatus and Culex erraticus mosquito larvae were associated with agricultural wetlands. [•] Culex territans mosquito larvae were associated with forested reference wetlands. [•] Landscape development intensity indices predicted the distributions of mosquito species in an agricultural landscape. [•] Mosquitoes are valuable bioindicators of wetland condition in an agroecosystem. [ABSTRACT FROM AUTHOR]

Abstract: The highly weathered, low-carbon, intensively cropped, drought-prone Coastal Plain soils of Georgia are susceptible to runoff and soil loss, especially at certain times of the year when soil water contents are elevated. We quantified the effects of antecedent water content (AWC) on runoff (R) and sediment (E) losses from two loamy sands managed under conventional- (CT), strip- (ST), and/or no-till (NT) systems. Two AWC treatments were evaluated: field moist (FM) and pre-wet (PW), created with and without post pesticide application irrigations (∼12mm of water added with the rainfall simulated over 30min) for incorporation. Treatments (5) evaluated were: CT+FM, CT+PW, ST+FM, ST+PW, and NT+PW. Field plots, each 2-m×-3m, were established on each treatment. Each 6-m2 field plot received simulated rainfall at a variable rainfall intensity (I v) pattern for 70min (site 1) or a constant rainfall intensity (I c) pattern for 60min (site 2; I c =50.8mmh−1). Adding ∼12mm of water as herbicide incorporation increased AWCs of the 0–2 (3–9-fold) and 2–15 (23–117%)cm soil depths of PW plots compared to existing field moist soil conditions. Increase in AWC increased R (as much as 60%) and maximum R rates (as much as 62%), and decreased E (at least 59%) and maximum E rates (as much as 2.1-fold) for corresponding tillage treatments. Compared to CT plots, ST and NT plots decreased R (at least 2.6-fold) and maximum R rates (as much as 3-fold), and decreased E (at least 2.7-fold) and maximum E rates (at least 3.2-fold). Runoff curves for pre-wetted CT and ST plots were always higher than corresponding FM curves, whereas E curves for field moist CT and ST plots were always higher than corresponding PW curves. Changes in AWC and tillage affected detachment and transport processes controlling runoff and sediment yields. A more accurate measure of rainfall partitioning and detachment and transport processes affecting R and E losses was obtained when commonly occurring field conditions (increased AWC with irrigation; I v pattern derived from natural rainfall; commonly used tillage systems) were created and evaluated. [Copyright &y& Elsevier]

Abstract: Since transport of planktonic larvae is essential to the maintenance and expansion of many marine species, we examined the spatial and temporal distribution of green porcelain crab Petrolisthes armatus (Gibbes, 1850) larvae and the possible underlying physical and behavioral mechanisms using a combination of field observations and numerical modeling. The field study consisted of observations of larval abundance and distribution as well as hydrographic surveys of the Satilla River estuary on the east coast of the USA in August 2006. Larvae were found throughout the water column within the tributaries but primarily at depth in the main river. A numerical model was used to examine the effect of flow and possible larval behavior responsible for the observed distribution and the consequences for larval retention in the estuary. Model results that included downward larval movement are consistent with the field observations, supporting the hypothesis that P. armatus larvae vertically migrate within the water column, which aids in their retention within the estuary. [Copyright &y& Elsevier]

Evidence suggests that fiber-tempered pottery from the Ocmulgee Big Bend of the interior Coastal Plain in Georgia was technologically distinctive since it was used for direct-heat as opposed to indirect-heat cooking. It is proposed here that early pottery, accompanied by soapstone vessels, was adopted by people living in the interior Coastal Plain, away from areas of previous pottery concentrations, as the result of a shift in trading alliances coinciding with the growth of trading networks during the Late Archaic. [ABSTRACT FROM AUTHOR]