Registered users receive a variety of benefits including the ability to customize email alerts, create favorite journals list, and save searches.
Please note that a BioOne web account does not automatically grant access to full-text content. An institutional or society member subscription is required to view non-Open Access content.
Contact firstname.lastname@example.org with any questions.
The Southeastern American Kestrel (Falco sparverius paulus), a non-migratory subspecies of the widespread American Kestrel, has declined to the point that it is listed as threatened in Florida, the state in which it is most common. We studied the nesting biology of Southeastern American Kestrels in 1999 and 2000 at Eglin Air Force Base, FL, in old-growth longleaf pine savanna, a habitat type historically widely occupied by the kestrels. Most of the nest cavities we observed were in old-growth trees, both living and dead, and were originally excavated by Red-cockaded Woodpeckers (Picoides borealis) and then enlarged by other woodpecker species. Nesting success was 70% in 1999 and 56% in 2000. In 1999, 67% of eggs survived to become fledglings in successful nests, as did 58% in 2000. Nests in live pines and snags were equally successful, and nest success was positively related to cavity height in 1999. Reduced nesting success in 2000 may have been related to severe drought conditions. High nesting concentrations of up to 4 pairs per km2 were observed. We suggest that stands of old-growth longleaf pine, with little or no hardwood midstory and a relatively high number of snags, inhabited by Red-cockaded Woodpeckers, may constitute high quality habitat for Southeastern American Kestrels. Therefore, loss of longleaf pine habitat, degradation of remaining longleaf habitat due to fire suppression and removal of old-growth and snags, and the decline of the Red-cockaded Woodpecker, a species on which kestrels may have depended as a source of nest cavities historically, may have contributed to the decline of the Southeastern American Kestrel.
Since a comprehensive fish survey in 1968, four impoundments have been constructed in the Bear Creek (Tennessee River drainage) watershed in Alabama (Wall 1968). Data from this original study were compared to a recent survey in order to determine if any changes in fish species composition had occurred during the approximately 30 year time period. A comparison of similarity for 44 collections showed low similarity between the two surveys for a large percentage of sites visited (86% for Jaccard's Similarity and 62% for Morisita Similarity). Sites with low similarity between survey dates were typically associated with impoundments. Most species missing in the recent survey include species considered sensitive, such as cyprinids and percids. Species that have increased since 1968 include centrarchids, a group typically tolerant of impoundment and environmental change. Virtually all fish species composition differences indicate a less pristine fish assemblage in the more contemporary survey, suggesting that recent factors have had a negative effect on the fish assemblage of Bear Creek.
Benthic meiofauna are important food resources for marine fishes and crustaceans, some of which have important commercial value. Ray feeding activities produce pits that disturb intertidal and subtidal sediments. Our previous research showed that feeding pit formation reduced meiofaunal abundance inside intertidal pits. The purpose of the present study was to evaluate the recovery time of meiofauna as the summer season progressed. In July, meiofauna recovered by 4 tidal cycles (within 48 h) after pit formation. In August, meiofaunal numbers took 6–14 tidal cycles (72–168 h) to recover. The longer recovery time later in the summer may be due to the continuous disturbance of the sediments by ray feeding activity, as 16–19% of the intertidal surface area was disturbed by this activity.
The South Fork Holston River is one of three major tributaries of the Holston River, originating in Smyth County in southwestern Virginia and flowing southwesterly and then northwesterly to where it enters the Holston River at Kingsport, TN. Three dams constructed in the 1950s, Fort Patrick Henry, Boone and South Holston, impounded the entire stretch of river flowing through Tennessee. Identification of shell recovered from two prehistoric aboriginal sites, Eastman Rockshelter (40SL34) and Site 40SL330, and from two collections of relic shells plus species recorded from four localities by Ortmann (1918), provide evidence for a diverse and abundant naiad fauna prior to impoundment. Thirty-five species of mussels historically inhabited stretches of the South Fork Holston River flowing through Tennessee; all have been extirpated. Populations of Actinonaias pectorosa, Lampsilis fasciola, Fusconaia subrotunda, and Ptychobranchus subtentum appear to have been four of the most abundant naiads inhabiting the river. In addition to the Asian clam, Corbicula fluminea, the giant floater (Pyganodon grandis) and paper pondshell (Utterbackia imbecillis) are invader species now common throughout the reservoirs.
During 2000–2002 we surveyed for salamanders in the larger limestone caves of Mississippi, all within the Vicksburg Group rock unit. We found four species: Plethodon mississippi was the most abundant, followed by Eurycea guttolineata, Eurycea cirrigera, and Desmognathus conanti. We did not find Pseudotriton montanus in any of the caves, and question the validity of an investigator's statement made nearly 45 years ago that, “it is one of the most numerous salamanders in Mississippi limestone caves.” The salamander fauna we found is similar to that of the only other comprehensive survey of salamanders in Mississippi caves, conducted almost thirty years ago.
I conducted a mark-recapture study of Siren lacertina and Amphiuma means for one year at a lake in north Florida and documented average individual movement, size class distribution, seasonal activity patterns, survival rates, and density estimates. I captured Siren lacertina more frequently in winter and A. means more frequently in spring. Recapture probabilities of both species were low, whereas survival rates and density estimates (1.3 salamanders/m2 for S. lacertina, 0.28 salamanders/m2 for A. means) were high. I recorded no individual movement of over 10 m for either species. Sirens and amphiumas are large, predatory generalists that can have substantial biomass in wetlands (233 g/m2 and 44 g/m2, respectively, at this study site), and therefore can impact many other wetland species. Thus, more attention must be focused on evaluating and monitoring their populations.
We document the occurrence of the Bird-voiced Treefrog (Hyla avivoca), at 32 sites in the upper Ouachita River system of Arkansas, including specimens from the Little Missouri and Saline River tributaries. This more than doubles the total number of sites from which this frog is known in Arkansas, and the distributional limit coincides with the interface of the Ouachita Mountains and the Gulf Coastal Plain. West of the Mississippi River, only a few localities are known for this species in Oklahoma and Louisiana, making the Arkansas populations important for the conservation of the species.
A recent study suggested that reproductive nest-association of nonindigenous rough shiner (Notropis baileyi) may be contributing to changes in abundances of native bluehead chubs (Nocomis leptocephalus) and bandfin shiners (Luxilus zonistius) in the Chattahoochee River system. We used video-recording techniques to determine whether rough shiners associate with nests built by native fishes, and if so, whether they influence the reproduction of other native nest-associates. Results indicated that rough shiners did not appear to adversely affect native fish reproductive behavior, and in fact, may be competitively excluded from optimal spawning areas by other nest-associates. These results support the hypothesis that reproductive nest-association by nonindigenous rough shiner may facilitate its increase as well as the increase of bluehead chubs within this drainage. Previously unreported spawning behaviors of rough shiner are also described.
An association between vine habit and cordate leaf shape in higher plants has been reported, but previous comparative analyses have not taken into account phylogenetic history. We surveyed the flora of the Carolinas and used phylogenetic comparative methods to test the hypothesized relationship. We found 25 phylogenetically independent vine taxa in the Carolina flora and, for each, attempted to identify its hypothesized non-vine sister taxon based upon recent phylogenetic studies. Using conservative criteria for vine habit and leaf shape determinations, a sign test revealed a significant association between the two traits. The addition of taxa for which information was slightly more ambiguous increased the strength of the association. Our findings suggest that convergence in leaf shape of vine taxa may result from a selective advantage of cordate leaves in plants with a climbing habit. We discuss possible adaptive explanations for the observed association.
The savannah lilliput (Toxolasma pullus, Bivalvia: Unionidae) is the only member of its genus represented along the mid-Atlantic slope. The rarity, limited range, and declining status of this species have caused concern among resource managers for its conservation. Little is known about the life history of T. pullus; such information is necessary for recovery of the species. We conducted a fish host trial and examined population demographics of T. pullus from University Lake, NC. Toxolasma pullus appears to be a long-term brooder, brooding into August. Hybrid bluegill (Lepomis macrochirus × L. cyanellus) are suitable hosts for T. pullus, however, other Lepomis species may also serve as hosts. The sex ratio of the population was 1:1. Most specimens of T. pullus were between 4 and 6 years old; the oldest specimen was 9 years of age. Predation by muskrats and raccoons may be an important source of mortality in University Lake.
The species composition of the Southern Loam Hills was partially inventoried during a study to identify landscape scale land units. Eight land units with unique species composition were identified. The study identified 252 species in 83 families and 172 genera. These numbers partially express the plant diversity of the Southern Loam Hills. No riparian or depressional wetlands were included in the study.
Features of floral anatomy and pollination biology of Cyrilla racemiflora were studied to complement existing data on pollinators. Floral anatomy and development were observed through bright field, fluorescence, and scanning electron microscopy. Pollination biology was investigated through a pollinator-exclusion bagging experiment. During maturation the floral parts undergo a number of color changes, chief among them being the greening of the nectary at the base of the ovary. The bilobed stigma surfaces are of the wet type, the fluid being lipoidal. The ovarian nectary possesses papillate epidermal cells, a distinct cuticle, and stomates through which secretion probably occurs. Petals have an adaxial thickening whose precise function is unknown. Calcium-containing crystals appear at certain sites in the anthers and might influence the process of dehiscence. No self-incompatibility exists as regards pollen-tube germination and growth, although pollination is rare in the absence of a vector. Self-pollination can lead to seed set.
This paper describes an unmanaged 1930s-era pine-hardwood stand on a minor stream terrace in Ashley County, AR. Probably inventoried as a part of an early growth and yield study, the sample plot was approximately 3.2 ha in size and contained at least 21 tree species. Loblolly pine comprised 39.1% of all stems, followed by willow oak (12.7%), winged elm (9.6%), sweetgum (7.8%), water oak (6.7%), white oak (6.2%), red oak (4.9%), and hickory (4.6%). Pine, sweetgum, and oak dominated the midcanopy and overstory, with few late successional species. Stand basal area averaged 32 m2/ha, with 409 live trees/ha. The dominance of shade intolerant species, the lack of very big trees, and a scarcity of snags suggested that this stand was second-growth and likely arose from a disturbance in the mid-19th Century. Because this forest was sampled in the 1930s, its composition and structure should better reflect mature presettlement pine-hardwoods on minor stream terrace sites than modern examples.
Increasing development north of Charlotte, NC, threatens aquatic life in streams by reducing riparian zones and increasing runoff. Runoff, sedimentation from erosion, and poor construction practices are principal sources of pollution. We asked how land use and disturbance affected benthic insects. We visited nine streams from May to October 2001, collected data on insect diversity, chemistry, and physical habitat. We used a Geographic Information System to delineate watersheds and land use patterns. Watersheds were categorized based on land use, abiotic variables, and disturbance. Insect communities were more diverse in streams draining low disturbance watersheds than in streams draining highly developed watersheds. Sensitive taxa were found in streams with extensively forested watersheds, but were nonexistent in extensively developed watersheds. Disturbances occurring in streams caused declines in diversity, often eliminating sensitive taxa. Aquatic insect diversity is related to land use patterns and disturbances, and anthropogenic alteration of habitat has negative consequences to that diversity.
The effects of drying and rewetting on rotifer egg bank hatching were examined for three habitats in a mainstem reservoir embayment, Kentucky Lake, KY: a littoral zone with an annual drying and wetting cycle, a floodplain that was only rarely inundated, and a permanently wetted embayment. Hatching from surface sediments also was compared with hatching from sediments 4–10 cm and 14–20 cm deep. Seven rotifer species normally associated with littoral zones and two other zooplankton species hatched from sediments following rewetting. No pelagic species hatched. Surface sediments normally experiencing drying and rewetting cycles had a greater number of species than permanently wetted sediments. Eggs hatched more quickly from deeper than surface sediments. Results demonstrated that reservoir water level fluctuations may play a role in rotifer community dynamics by providing favorable conditions for littoral as well as pelagic species.
Discarded beverage bottles have been recognized as a source of mortality for small mammals since the 1960s. We walked 4.34 km of moderately to heavily traveled highways and interstate interchanges near Newport News, VA, and counted discarded bottles and vertebrates trapped inside. We found 10,681 bottles, for an average of 2461 bottles/km. Greater numbers of bottles per km were found along heavily-traveled roadways than along moderately-traveled roads. Although only 4% of bottles trapped vertebrates, 795 vertebrates were found in those bottles with an average of 183.2/km of roadway. Most animals killed in bottles were Blarina brevicauda. Other casualties included Peromyscus leucopus, Microtus pinetorum, Mus musculus, Sorex longirostris, Cryptotis parva, lizards, and plethodontid salamanders. Although we found no rare or endangered species, similar numbers of bottles likely occur in areas with species of shrews, rodents, or salamanders whose populations are declining.