Long-term trends of subtidal macrobenthos in North Inlet,South Carolina

Analyses of seasonal and yearly trends in subtidal macrobenthic samples collected bi-weekly at a sandy site (1981–1984) and a muddy site (1981–1985) in North Inlet, South Carolina, show large fluctations in abundance and high variability between replicate samples. Sampling variability at the sandy site, thought to be influenced more by physical disturbance than by biotic interactions, was especially high and prevented the interpretation of seasonal trends in abundance. Increased replication at the muddy site in 1985 revealed abundance patterns of winter/spring maxima and summer minima. Despite short-term (seasonal) and high year-to-year variability, the fauna at both sites were characterized by long-term stability in abundance. That is, although abundances varied considerably between seasons or years only 9 of 22 taxa analyzed showed a directional change in abundance. These 9 taxa increased in abundance over the four (sandy site) or five (muddy site) years of examination while the other 13 taxa fluctuated about a mean value. The taxonomic composition of benthic fauna at both sites was also very stable through time, with the sandy site always numerically dominated, in order, by polychaetes, amphipods, and bivalves and the muddy site by polychaetes, oligochaetes, and bivalves.     

Stratigraphy and geologic history of a southeastern salt marsh basin,North Inlet,South Carolina,USA

Forty seven vibracores and fifteen radiocarbon dates have beenobtained to outline the Holocene history of the North Inlet saltmarsh basin. Marsh deposits date from about 3500 years BP and havetransgressed over a Late Pleistocene beach-ridge terrain that waspartly eroded by Late Holocene tidal channel meandering. Marsh mudalso has prograded southward over shallow subtidal estuarine Macomamuds which date from about 4500 years BP and which are stillaccumulating in adjacent Winyah Bay. The southward migration of themarsh environment probably is due to the southward migration ofboth North Inlet and the mouth of Winyah Bay. The stratigraphy ofthe North Inlet basin offers no evidence for Late Holocene sea-level oscillations.Application of this model of marsh history to the study long-term ecosystem succession driven by slowly rising sea level isdiscussed.     

Wood abundance in urban and rural streams in northwestern South Carolina

Hydrobiologia - In streams and rivers, wood from riparian vegetation contributes to habitat complexity and substrates for stream biota, influences channel geomorphology, alters flow, retains...     

The suprapopulation dynamics of Bothriocephalus acheilognathi in a North Carolina reservoir: abundance, dispersion, and prevalence

A 2 1/2-year study (September 1980-March 1983) of abundance, dispersion, and prevalence of the pseudophyllidean cestode, Bothriocephalus acheilognathi, in 3 species of fish (Gambusia affinis, Notropis lutrensis, and Pimephales promelas) was conducted in 3 ecologically distinct areas of a North Carolina cooling pond. Mean infrapopulation density and prevalence differed by site, season, and species and size of hosts. Degree of aggregation and abundance and prevalence of gravid worms differed by species of host. Abundance of gravid worms was significantly lower in metapopulations from localities that received power plant effluents. The differences in infrapopulation density, prevalence, and aggregation appeared to be related to predator-prey interactions, which varied with season and local community structure. Differences in abundance of gravid worms, on the other hand, were probably caused by differential suitability of hosts and by local variation in selenium concentration in the water column. Thus, it appears that both biotic and abiotic components of the host community determined the suprapopulation dynamics of B. acheilognathi in Belews Lake.     

Respiration rates of dominant hydromedusae in the North Inlet tidal estuary during winter and summer

The objective of this study was to quantify the respiratoryrequirements and oxygen consumption rates for seasonal hydromedusaepopulations in the North Inlet estuary, Georgetown, SC, USA.Respiration rates were determined for hydromedusae collectedin January 2006, 2007 and July 2006 using microrespirometry.The numerically dominant gelatinous predators were Nemopsisbachei (January 2006 and 2007) and Bougainvillia muscus (July2006). Seasonal oxygen consumption rates were low (0.80–1.27µmol O₂ g^–1 h^–1). Q₁₀ values were high duringJanuary 2006 and July 2006 (4.7), but low during January 2007(0.5), suggesting hydromedusae were sensitive to the exposuretemperatures (7–34°C) in this study and well adaptedto the temperature range encountered in this estuary. Moreover,the oxygen consumption rates during July 2006 showed significantdifferences between the two species. The allometric relationshipbetween respiration rate and hydromedusae weight differed seasonally.Our findings suggest hydromedusae can persist in hypoxic conditionsand may partially explain the frequently observed increase inthese cnidarians under conditions of low dissolved oxygen concentrations.     

Distribution of the Family Hydropsychidae (Trichoptera) in the Savannah River Basin of North Carolina,South Carolina and Georgia

Hydropsychids were collected along the length of the Savannah River and its headwaters and tributaries. Species distribution was correlated with chemical and physical properties of water, altitude and stream size. Seven genera and 35 species were found among approximately 100,000 specimens collected. Fourteen species divided into three groups on the bases of altitude and stream size preferences. Turbidity, conductivity, temperature, carbonate, nitrate and nitrite increased along the river's course, whereas maximum velocity and dissolved oxygen decreased. For these factors the maximum value tolerated by a species was associated with the species distribution. The genera Hydropsyche and Cheumatopsyche were the most widely distributed. Several species of these two genera had quite large distributional ranges while others had quite restricted ranges.     

Life histories,abundance and distribution of some macroinvertebrates from a South Carolina,USA coastal plain stream

The life histories, densities and distribution patterns of the most abundant macroinvertebrates, exclusive of chironomids and oligochaetes, are reported for a low-gradient, second-order, blackwater stream on the Coastal Plain of South Carolina, USA. Univoltine life histories were found for all species of Coleoptera (Ancyronyx variegata, Macronychus glabratus, Dubiraphia quadrinotata and Hydroporus clypealis) and most species of Ephemeroptera (Eurylophella temporalis, Paraleptophlebia volitans and Hexagenia munda), although the mayfly Stenonema modestum was at least bivoltine. Both univoltinism (Macrostemum carolina and Pycnopsyche luculenta), partial bivoltinism (Nyctiophylax affinis) and complete bivoltinism (Hydropsyche decalda, Cheumatopsyche sp., Phylocentropus placidus and probably Chimarra florida) were found among the Trichoptera. Odonate species were both univoltine (Calopteryx dimidiata, Enallagma divagans and Epitheca cynosura) and semivoltine (Boyeria vinosa, Gomphus lividus and Macromia georgina). The alderfly Sialis aequalis and the isopod Asellus laticaudatus were univoltine, while the blackfly Simulium taxodium produced at least 6 generations per year. Groups of functionally-related species within the orders Odonata, Trichoptera and Coleoptera each exhibited possible temporal and/or spatial segregation.     

Impact of drought upon fish assemblage structure in two South Carolina Piedmont streams

The effects of drought on fish assemblages were studied in the Indian Creek (228 km²) and Kings Creek (46 km²) watersheds located in the Piedmont Province of South Carolina. Water and fish samples were collected at 13 localities during drought conditions in 2000 and again under post-drought conditions in 2003. Abundance, species richness, and Simpson’s diversity were calculated for each locality, and the masses and lengths of individual fishes were measured to determine total biomass and length distributions for each species. Assemblages were significantly different from 2000 to 2003 at 10 of the 13 sample localities (χ² test for association; p < 0.05). The family Cyprinidae (minnows) was numerically dominant in both years and in both watersheds, but their dominance declined somewhat following the drought due to lower numbers of Nocomis leptocephalus and Notropis lutipinnis in 2003 collections. However, some cyprinids increased in abundance in 2003 collections, most notably Semotilus atromaculatus and Hybopsis hypsinotus. Abundance of catostomids (suckers) and ictalurids (catfish) was also decreased post drought. Conversely, centrarchids (sunfish) increased in dominance in 2003, especially the species Lepomis macrochirus and Lepomis gulosus. Many more juveniles and young of the year were observed in 2003 collections, suggesting that most species exhibited greater reproductive success following the drought. The significant differences in water chemistry observed between the two years were not associated with any change in fish community structure. Instead, we attributed the observed differences in fish assemblages to changes in habitat structure associated with higher rainfall during post-drought conditions. Finally, sample localities showed high variability in common measures of assemblage structure, including abundance, species richness, and diversity. We hypothesize that the observed variability in community structure is caused by the heterogeneous habitat structure and morphology of these small Piedmont Province streams.     

The intra-annual variability of soft-bottom macrobenthos abundance patterns in the North Channel of the Seine estuary

Temporal and spatial variability of the Abra alba–Pectinaria koreni and Macoma balthica communities was examined in the northern part of the Seine estuary (North Channel) over different space and time scales in order to assess the role that the hydrologic regime and/or anthropogenic influences play in defining benthic communities over time. Sediment in the North Channel displayed strong spatial and temporal variability, sustained by intense sediment transport episodes. Total macrobenthic abundances ranged widely on the course of the year and there was no evidence of a seasonal signal for the density fluctuations, whatever the spatial scale considered. The bio-sedimentary dynamics can be divided into two periods: the first corresponds to the high flow rate period (January–May) during which fauna is influenced by fine silt/clay deposition, and the second to the low flow rate period (June–December) during which sandy deposits prevail. Despite the absence of significant correlations between sediment composition and abundance, episodes of sediment transport seem to be an important structuring mechanism in the Seine estuary. As a consequence, the faunal composition varied throughout the year. The winter and spring fauna, characterised by species living on muddy fine-sands or muds, were enriched during the summer and autumn by species living in clean fine sand, such as Donax vittatus, Nephtys cirrosa or Spio decoratus, mainly represented by adult individuals. Secondary settlement of drifters may explain the rapid structuration of assemblages a few days after the sandy deposits. Our results suggest the importance of the bentho-pelagic coupling, primarily induced by the sedimentary instability, on the macrobenthic fauna dynamics. The intra-annual variability of assemblages at the mouth of the Seine river and the silted situation of the North Channel might simply be the result of the silting up and alteration of the inner estuary, generated by several decades of man-made modifications and natural processes.     

Population density, species abundance, and breeding structure of subterranean termite colonies in and around infested houses in central North Carolina

Pressure from subterranean termites is known to vary geographically across the United States, but there are few quantitative studies concerning the threat of structural infestation for any geographic region. We assessed the number and locations of termite colonies present on 20 infested residential properties in central North Carolina, where subterranean termite pressure is considered to be heavy. This was achieved by using microsatellite markers to determine colony identity of termites collected over 6-14 mo from mud tubes in structures, below-ground monitors, and wood debris in the yard. In total, we identified 188 distinct colonies and determined their breeding structures. Reticulitermes flavipes (Kollar) was by far the most common species, accounting for nearly 90% of all colonies; the remaining colonies belonged to Reticulitermes hageni Banks and Reticulitermes virginicus (Banks). In four cases, there were two colonies infesting a structure simultaneously; in all other cases only a single colony was detected in the structure. Colony densities were high, averaging 62 colonies per ha (25 per acre) with a maximum of 185 colonies per ha (75 colonies per acre). Foraging ranges of R. flavipes and R. hageni colonies were generally small (<30 linear m), and most colonies were headed by a single pair of monogamous reproductives with nearly all the remaining colonies headed by relatively few inbreeding descendants of the original monogamous pair. These results provide the most detailed picture to date of the number, distribution, and colony characteristics of subterranean termite colonies located in and around residential structures.     

Diversity and Occurrence of Plant-parasitic Nematodes Associated with Golf Course Turfgrasses in North and South Carolina,USA

One hundred and eleven golf courses from 39 counties in the Carolinas were surveyed for plant-parasitic nematodes. Species diversity within habitats was analyzed with five diversity indices including Diversity index (H’), Evenness (J’), Richness (SR), Dominance (λ) and Diversity (H₂). The results revealed a remarkably high diversity of 24 nematode species belonging to 19 genera and 11 families. Of those, 23 species were found in SC, 19 species in NC, and 18 species were detected in both states. Helicotylenchus dihystera, Mesocriconema xenoplax, Hoplolaimus galeatus, Tylenchorhynchus claytoni, Belonolaimus longicaudatus, Meloidogyne graminis and Paratrichodorus minor were the most prevalent and abundant species in golf course turfgrasses in both states. Twelve species were new records of plant parasitic nematodes in turfgrasses in both NC and SC. The results also revealed effects of different habitats on diversity of nematode species in turfgrass ecosystem. H’ and SR values were higher in SC than in NC. H’, J’ and H₂ values were significantly higher in sandy than in clay soil in NC, but no significant differences between sand and clay soil were detected in SC or in pooled data from both states. There were no significant differences for all indices among the management zones (putting green, fairway and tee) in NC. However, in SC and pooled data, H’, SR and H₂ were significantly higher in putting greens than in fairways and tees. Significant differences from different grass species (bermudagrass, creeping bentgrass and zoysiagrass) were detected only in H’, which was significantly higher in zoysiagrass than in bentgrass or bermudagrass in NC. In pooled data, H’ was significantly higher in zoysiagrass samples than in creeping bentgrass samples but was not significantly different from bermudagrass samples.     

Sediment quality of the Neuse River estuary, North Carolina: an integrated assessment of sediment contamination, toxicity, and condition of benthic fauna

A study of ecological conditions associatedwith bottom sediments in the Neuse Riverestuary, U.S.A. was undertaken during summer1998. Sampling of macroinfauna, sedimentsfor toxicity and chemical contaminant analyses,and physical properties of water was carriedout synoptically over a four-day period at 20stations from the mouth of the Neuse River atPamlico Sound to approximately 90 km upstream. The distribution and condition of benthicinfauna were found to vary in response tonatural and anthropogenic factors, and apparentassociations between degraded infaunalcondition and sediment contamination and/ortoxicity were observed over roughly half of thesampled area (7 stations, 47% area). With fewexceptions, degraded benthic conditions wereassociated with significant sedimentcontamination or toxicity. High sedimentcontaminant levels were found to occur almostexclusively in fine-grained, organic-rich muds. These results suggest that high organic loadingand chemical contaminant inputs to the NeuseRiver, coupled with low freshwater dischargerates and high residence times in the lowerestuary, have contributed to degraded benthicconditions at these sites.     

High sympagic metazoan abundance in platelet layers at Drescher Inlet, Weddell Sea, Antarctica

The metazoan fauna of platelet layers was investigated at Drescher Inlet, Weddell Sea, Antarctica in the late summer of 1995. Twenty-eight species were found, many of them new to science. The most abundant subclass was the Copepoda, of which almost 90% of the individuals belong to only three species: Drescheriella glacialis, Stephos longipes and Paralabidocera antarctica. Among copepods, Harpacticoida was the largest group, represented by 16 species. Total abundance varied between 40 and 120 individuals l⁻¹. Abundances and population structure were comparable to other especially porous sea-ice habitats. Results indicate competitive exclusion among the three dominant species. The finding of a profuse meiofauna in platelet layers may explain enigmatic concentrations of ammonium and phosphate commonly detected there. Accepted: 5 February 1999     

Bat rabies in South Carolina, 1970-90.

This retrospective study examines the geographic and temporal distribution of bat species submitted for rabies testing in South Carolina (USA) from 1970 to 1990. Histories of human or animal exposures to rabid and nonrabid bats submitted during this time period were compared. Two hundred and thirty-one bats were found to be rabid from the 2,657 bats submitted over this 20 yr period. The two species most frequently submitted for testing were Lasiurus borealis with 785 specimens (30% of the total) and Nycticeius humeralis with 607 specimens (22% of the total). Lasiurus borealis also had the highest prevalence of rabies (18%) while N. humeralis had the lowest prevalence (3%). Fifty-one percent (1,259) of the bats received for testing were submitted from June through August. The majority (54%) of rabid bats were received from August through October.     

Influence of preceding crop on wireworm (Coleoptera: Elateridae) abundance in the coastal plain of North Carolina

Three studies were conducted to determine the effect of preceding crop on wireworm (Coleoptera: Elateridae) abundance in the coastal plain of North Carolina. In all three studies, samples of wireworm populations were taken from the soil by using oat, Avena sativa L., baits. Treatments were defined by the previous year's crop and were chosen to reflect common crop rotations in the region. Across all three studies, eight wireworm species were recovered from the baits: Conoderus amplicollis (Gyllenhal), Conoderus bellus (Say), Conoderus falli (Lane), Conoderus lividus (Degeer), Conoderus scissus (Schaeffer), Conoderus vespertinus (F.), Glyphonyx bimarginatus (Schaeffer), and Melanotus communis (Gyllenhal). The effect of corn, Zea mays L.; cotton, Gossypium hirsutum L.; fallow; soybean, Clycine max (L.) Merr.; sweet potato, Ipomoea batatas (L.) Lam.; and tobacco (Nicotiana spp.) was evaluated in a small-plot replicated study. M. communis was the most frequently collected species in the small-plot study and was found in significantly higher numbers following soybean and corn. The mean total number of wireworms per bait (all species) was highest following soybean. A second study conducted in late fall and early spring assessed the abundance of overwintering wireworm populations in commercial fields planted to corn, cotton, peanut (Arachis hypogaea L.), soybean, sweet potato, and tobacco in the most recent previous growing season. C. lividus was the most abundant species, and the mean total number of wireworms was highest following corn and soybean. A survey was conducted in commercial sweet potato in late spring and early summer in fields that had been planted to corn, cotton, cucurbit (Cucurbita pepo L.), peanut, soybean, sweet potato, or tobacco in the most recent previous growing season. C. vespertinus was the most abundant species, and the mean total number of wireworms per bait was highest following corn.