Population characteristics of Siren lacertina and Amphiuma means in north Florida
Abstract not supplied at this time
Southeastern Naturalist↗
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Sediment-quality assessment of the Lower Oconee River
Sediment quality was assessed at multiple sites in the lower Oconee River, GA to identify contaminants potentially affecting the survival of an endemic ?At-Risk? species of fish, the robust redhorse (Moxostoma robustum). Five major tributaries that drain urban and agricultural watersheds enter this stretch of river and several carry permitted municipal and industrial effluents containing Cd, Cu, and Zn. Sediments for chemical analyses and toxicity tests with Hyalella azteca (Amphipoda) were collected at 12 locations that included sites above and below the major tributaries. Compared to national data bases and to the nearby Apalachicola-Chattahoochee-Flint watershed, sediments from the Oconee River had elevated concentrations of Cr, Cu, Hg and Zn. Zinc concentrations showed a marked increase in sediment downstream of the confluence of Buffalo Creek demonstrating contributions from permitted municipal and industrial effluents discharged to that tributary. When exposed to these sediments, growth of H. azteca was significantly reduced. Amphipod growth was also reduced when exposed to sediments collected from another site due to toxicity from Cr. Sediments in the lower Oconee River appear to be impaired due to metal contamination and could pose a threat to organisms, such as the robust redhorse, that are closely associated with this matrix during their life cycle.
Southeastern Naturalist↗
Unionid habitat and assemblage composition in coastal plain tributaries of the Flint River (Georgia)
Effective conservation of mussels in streams of the lower Flint River basin, southwest Georgia, requires more rigorous understanding of mussel-habitat associations and factors shaping assemblage composition in stream reaches. We surveyed mussels and habitat conditions at 46 locations, and used regression, correlation and multivariate direct gradient analysis (Canonical Correspondence Analyses) to identify species-habitat relationships and characteristic species-assemblage types in Flint basin streams. Riparian wetland and catchment forest cover, average mid-channel depth, and drainage network position accounted for 49% of the variability in mussel species richness, 36% of the variability in unionid abundance, and 32% of the variability observed in Shannon-Wiener diversity across survey sites. Species were grouped into four assemblage types based on their habitat associations: large-river-riffle associates, slackwater associates, habitat generalists, and stream-run associates. Results are broadly concordant with anecdotal reports of mussel-habitat relationships and provide insight into the habitat conservation needs of mussels.
Southeastern Naturalist↗
Analysis of spawning behavior, habitat, and season of the federally threatened Etheostoma scotti, Cherokee darter (Osteichthyes: Percidae)
Etheostoma scotti (Cherokee darter) is a member of the subgenus Ulocentra and a federally threatened endemic to the Etowah River system, GA. Field observations of spawning behavior of the Cherokee darter were made at five stream sites to identify spawning season and habitat over two field seasons. Cherokee darters primarily spawn in pool habitats between mid-March and early June, at temperatures between 11 and 18 ?C. Egg deposition was typically on large gravel substrate, but ranged from gravel to bedrock in size and included woody debris. Spawning occurred in a variety of depths (0.09-0.59 m) and velocities (0-0.68 m/s).
Southeastern Naturalist↗
The vertebrate fauna of Ichauway, Baker County, GA
Less than 4% of the once extensive Pinus palustris (longleaf pine) ecosystem remains today. Although longleaf pine habitats are recognized for their high species diversity, few published accounts document the vertebrate faunas of remaining tracts. Here we report on the vertebrate species richness of lchauway, an 11,300-ha property in Baker County, GA. The property includes ca. 7300 ha of longleaf pine with native ground cover, along with more than 30 seasonal wetlands and ca. 45 km of riparian habitat associated with Ichawaynochaway Creek, Big Cypress Creek, and the Flint River. The fauna includes 61 species of fish, 31 amphibians, 53 reptiles, 191 birds, and 41 mammals. Despite the relative isolation of the property from other natural ecosystems, the vertebrate fauna of lchauway is remarkably diverse and may offer an example of reference conditions to guide restoration of longleaf pine forests, associated seasonal wetlands, and riparian areas elsewhere in the southeastern U S.
Southeastern Naturalist↗
Winter bird population studies and project prairie birds for surveying grassland birds
We compared 2 survey methods for assessing winter bird communities in temperate grasslands: Winter Bird Population Study surveys are area-searches that have long been used in a variety of habitats whereas Project Prairie Bird surveys employ active-flushing techniques on strip-transects and are intended for use in grasslands. We used both methods to survey birds on 14 herbaceous reforested sites and 9 coastal pine savannas during winter and compared resultant estimates of species richness and relative abundance. These techniques did not yield similar estimates of avian populations. We found Winter Bird Population Studies consistently produced higher estimates of species richness, whereas Project Prairie Birds produced higher estimates of avian abundance for some species. When it is important to identify all species within the winter bird community, Winter Bird Population Studies should be the survey method of choice. If estimates of the abundance of relatively secretive grassland bird species are desired, the use of Project Prairie Birds protocols is warranted. However, we suggest that both survey techniques, as currently employed, are deficient and recommend distance- based survey methods that provide species-specific estimates of detection probabilities be incorporated into these survey methods.
Southeastern Naturalist↗
Predictors of occurrence of the aquatic macrophyte Podostemum ceratophyllum in a southern Appalachian River
The aquatic macrophyte Podostemum ceratophyllum (Hornleaf Riverweed) commonly provides habitat for invertebrates and fishes in flowing-water portions of Piedmont and Appalachian streams in the eastern US. We quantified variation in percent cover by P. ceratophyllum in a 39-km reach of the Conasauga River, TN and GA, to test the hypothesis that cover decreased with increasing non-forest land use. We estimated percent P. ceratophyllum cover in quadrats (0.09 m 2 ) placed at random coordinates within 20 randomly selected shoals. We then used hierarchical logistic regression, in an information-theoretic framework, to evaluate relative support for models incorporating alternative combinations of microhabitat and shoal-level variables to predict the occurrence of high (≥50%) P. ceratophyllum cover. As expected, bed sediment size and measures of light availability (location in the center of the channel, canopy cover) were included in best-supported models and had similar estimated-effect sizes across models. Podostemum ceratophyllum cover declined with increasing watershed size (included in 8 of 13 models in the confidence set of models); however, this decrease in cover was not well predicted by variation in land use. Focused monitoring of temporal and spatial trends in status of P. ceratophyllum are important due to its biotic importance in fast-flowing waters and its potential sensitivity to landscape-level changes, such as declines in forested land cover and homogenization of benthic habitats.
Southeastern Naturalist↗
Life history of the striped newt at a north-central Florida breeding pond
I studied the life history of Striped Newts (Notophthalmus perstriatus) at a breeding pond in north-central Florida. Newts were captured in pitfall traps at a drift-fence as they migrated into and out of the pond basin. During the 2-year study, I recorded 10,290 captures (8,127 individuals) of newts at the drift-fence. Newts were active during each month of the study, but there were four peak activity periods, each of which included immigration and emigration events. Immigration events were almost exclusively comprised of adults, whereas emigration events were comprised of adults and recently transformed larvae. I documented 5,296 recently transformed, immature larvae (efts) and 435 recently transformed mature larvae (paedomorphs) during four distinct periods of emigration. Efts matured in the uplands before returning to the pond to breed. In the uplands, male efts (n = 16) grew 0.0183 mm/day on average, whereas average female (n = 24) growth was 0.0167 mm/day. Immigrating adults of both sexes were significantly smaller than emigrating adults. Emigrating efts were smallest, followed by emigrating paedomorphs, immigrating adults, then emigrating adults. The overall adult sex ratio was 1:1.25 (m:f). Sex ratio of emigrating paedomorphs was highly skewed towards females, with one male for every 4.43 females. Newts tended to move during wetter periods, and captures were significantly correlated with rainfall, but rainfall was a poor predictor of the magnitude of newt movements.
Southeastern Naturalist↗
Status and reproduction of Gulf coast strain walleye in a Tombigbee River tributary
Walleye (Sander vitreus [Mitchill]) are native to rivers and streams in the Mobile River basin in Mississippi and Alabama. These populations comprise a genetically unique strain (Gulf coast walleye, GCW) and represent the southernmost distribution of walleye in the United States. Luxapallila Creek was considered an important spawning site for GCW prior to and shortly after impoundment of the Tombigbee River in 1980. Extensive sampling in Luxapallila Creek in 2001 and 2002 collected only one larval walleye. Microsatellite DNA analysis suggested 14 of 16 adult walleye from Luxapallila Creek were hatchery-produced fish or their progeny. Controlled angling catch rates of adult walleye have declined since 1997. The scarcity of wild-spawned walleye and the similarity of wild-caught and hatchery broodstock walleye indicates that the GCW population in, or spawning in, Luxapallila Creek is sustained by stocking and recruitment from these stocked fish may be diminishing.
Southeastern Naturalist↗
Density and habitat associations of Barred Owls at the edge of their range in Oklahoma
We assessed breeding-pair density and habitat associations of Barred Owls (Strix varia) at the edge of their range in north-central Oklahoma in 1995-1996. We played taped calls of Barred Owls to solicit and record responses (visual and auditory) and thereby determine density in our 1155-ha study area. Numbers of owls ranged from 7 pairs in 1995 to 11 pairs in 1996, or 1 Barred Owl pair/105-165 ha in a relatively contiguous bottomland forest. To assess habitat associations, we overlaid core areas of owl activity, as inferred from the locations of Barred Owl responses, on aerial photographs and quantified habitats in a 0.65-km2 cell surrounding owl core areas. Barred owl pairs were associated with closed-canopy forest (62.8%), fallow agricultural fields (10.6%), water (8.1%), and treeless (open) areas (6.2%), which differed from single owls (presumed nonbreeders) that showed a greater affinity for open-canopy forest and agricultural fields.
Southeastern Naturalist↗
Composition of breeding bird communities in Gulf Coast Chenier Plain marshes: Effects of winter burning
Marsh managers along the Gulf Coast Chenier Plain frequently use winter burns to alter marsh vegetation and improve habitat quality for wintering waterfowl. However, effects of these burns on marsh avifauna are not well documented. We recorded abundances of breeding bird species and vegetation structure in burned and unburned control marshes during one breeding season before (1996) and two breeding seasons after (1997, 1998) experimental winter burns. We used non-metric multidimensional scaling analysis to assess the extent and direction of changes in bird community compositions of burned and unburned control marshes and to investigate the influence of vegetation structure on bird community composition. Overall, we found that Seaside Sparrows (Emberizidae: Ammodramus maritimus [Wilson]) and Red-winged Blackbirds and Boat-tailed Grackles (Icteridae: Agelaius phoeniceus [L.] and Quiscalus major Vieillot, respectively) comprised > 85% of observed birds. In burned marshes during the first breeding season following experimental burns (1997), icterid abundance increased while Seaside Sparrow abundance decreased relative to pre-burn (1996) conditions. This pattern was reversed during the second breeding season post-burn. No obvious patterns of change in avian abundance were detected in unburned control marshes over the 3-year period. Qualitative changes in breeding bird community composition were related to effects of winter burning on percent cover of dead vegetation and Spartina patens (Aiton) Muhl.
Southeastern Naturalist↗
Marine fishes new to continental United States waters, North Carolina, and the Gulf of Mexico
Along the southeastern coast of the United States, hardground systems support a high diversity of sub-tropical and tropical fishes. Many of these hardgrounds occur in deep (ca. ??? 50 m) waters and their fauna is still poorly described; however, with concentrated sampling in these deeper areas, new records of fishes continue to emerge. In the northeastern Gulf of Mexico and off North Carolina, we used the Johnson-Sea-Link submersible, remotely operated vehicles, trawling gear, and angling gear to sample deep reef systems (38-248 m). We document five records of fishes new to continental United States waters, including Liopropoma aberrans, Parasphyraenops incisus, Lipogramma regia, Apogon gouldi, and Prognathodes guyanensis. We also report range extensions for eleven species: Gymnothorax hubbsi, Gymnothorax vicinus, Lepophidium staurophor, Cypselurus comatus, Liopropoma mowbrayi, Serranus annularis, Rypticus saponaceus, Caranx lugubris, Prognathodes aculeatus, Centropyge argi, and Canthigaster jamestyleri.
Southeastern Naturalist↗
Distribution and abundance of American eels in the White Oak River estuary, North Carolina
Apparent widespread declines in abundance of Anguilla rostrata (American eel) have reinforced the need for information regarding its life history and status. We used commercial eel pots and crab (peeler) pots to examine the distribution, condition, and abundance of American eels within the White Oak River estuary, NC, during summers of 2002-2003. Catch of American eels per overnight set was 0.35 (SE = 0.045) in 2002 and 0.49 (SE = 0.044) in 2003. There was not a significant linear relationship between catch per set and depth in 2002 (P = 0.31, depth range 0.9-3.4 m) or 2003 (P = 0.18, depth range 0.6-3.4 m). American eels from the White Oak River were in good condition, based on the slope of a length-weight relationship (3.41) compared to the median slope (3.15) from other systems. Estimates of population density from grid sampling in 2003 (300 mm and larger: 4.0-13.8 per ha) were similar to estimates for the Hudson River estuary, but substantially less than estimates from other (smaller) systems including tidal creeks within estuaries. Density estimates from coastal waters can be used with harvest records to examine whether overfishing has contributed to the recent apparent declines in American eel abundance.
Southeastern Naturalist↗
Ant community composition across a gradient of disturbed military landscapes at Fort Benning, Georgia
Military training, soil texture, and ground cover influence ant communities at Fort Benning, a military installation in west-central Georgia. We sampled 81,237 ground-dwelling ants (47 species in 20 genera) with pitfall traps at 40 sites on a continuum from nearly pristine forest to highly disturbed training areas. We also measured 15 environmental variables related to vegetation and soil. Sites disturbed by military training had fewer trees, less canopy cover, more bare ground, and more compact soils with shallower A-horizons than comparable undisturbed sites. Pheidole bicarinata, Dorymyrmex smithi, and Pogonomyrmex badius dominated the most highly disturbed sites. Competitively submissive myrmicines, such as Aphaenogaster and Crematogaster, and formicines, such as Camponotus and Formica, were abundant in the undisturbed sites. Solenopsis invicta occurred in all but the least disturbed sites. Ant community composition was a useful indicator of disturbance at Fort Benning.
Southeastern Naturalist↗
Size of spawning population, residence time, and territory shifts of individuals in the spawning aggregation of a riverine catostomid
Little is known about the behavior of individual fish in a spawning aggregation, specifically how long an individual remains in an aggregation. We monitored Moxostoma robustum (Cope) (Robust Redhorse) in a Savannah River spawning aggregation during spring 2004 and 2005 to provide an estimate of the total number of adults and the number of males comprising the aggregation and to determine male residence time and movements within a spawning aggregation. Robust Redhorse were captured using prepostioned grid electrofishers, identified to sex, weighed, measured, and implanted with a passive integrated transponder. Spawning aggregation size was estimated using a multiple census mark-and-recapture procedure. The spawning aggregation seemed to consist of approximately the same number of individuals (82-85) and males (50-56) during both years of this study. Individual males were present for a mean of 3.6 ?? 0.24 days (?? SE) during the 12-day spawning period. The mean distance between successive recaptures of individual males was 15.9 ?? 1.29 m (?? SE). We conclude that males establish spawning territories on a daily basis and are present within the spawning aggregation for at least 3-4 days. The relatively short duration of the aggregation may be the result of an extremely small population of adults. However, the behavior of individuals has the potential to influence population estimates made while fish are aggregated for spawning.
Southeastern Naturalist↗
Forward to the conservation, biology, and natural history of North American crayfishes
No abstract available.
Alabama, Arkansas, Georgia, Indiana, Maryland, Mis↗
Observations of acrobat ants (Crematogaster sp.) preying on the eggs of the invasive giant applesnail (Pomacea maculata)
Herein we provide direct evidence for the consumption of Pomacea maculata (Giant Applesnail) eggs by ants in the genus Crematogaster . The observations were made during removal of snail egg masses at the Hudson Woods Unit of the Texas Mid-Coast National Wildlife Refuge, TX. We observed acrobat ants ( Crematogaster sp.) removing snail eggs from an egg mass and carrying eggs back to their nest. While predation on Pomacea applesnail eggs has been reported elsewhere, to our knowledge this is the first time that it has been observed in North America.
Texas↗
Species richness, relative abundance, and habitat associations of nocturnal birds along the rio grande in Southern texas
The segment of the Rio Grande between International Falcon Reservoir and Del Rio, Texas (distance ca. 350 km), remains largely unexplored ornithologically. We surveyed nocturnal birds monthly during February-June 1998 at 19 stations along the Rio Grande (n = 6) and at upland stock ponds (n = 13) in Webb County, Texas. We conducted 10-min point counts (n = 89) after sunset and before moonset. Four species of owls and five species of nightjars were detected. Nightjars, as a group, were nearly five limes more abundant (mean number/count = 2.63) than owls (mean number = 0.55). The most, common owl, the great horned owl (Bubo virginianus), had a mean number of 0.25/point count. The mean for elf owls (Micrathene whitneyi) was 0.16/point count. The most common nightjars were the common poorwill (Phalaenoptilus nuttallii; 1.21/point count) and lesser nighthawk (Chordeiles acutipennir, 1.16/point count). Survey sites on the river supported more species (mean = 2.2) than did upland stock ponds (mean = 1.4). However, only one species (common pauraque, Nyctidromus albicollis) showed a preference for the river sites. Our results establish this segment of the Rio Grande in southern Texas as an area of high diversity of nightjars in the United States, matched (in numbers of species) only by southeastern Arizona and southwestern New Mexico.
Southwestern Naturalist↗