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 helpdesk@bioone.org with any questions.
Bottomland hardwood (BLH) forest ecosystems within the Lower Mississippi Alluvial Valley exist in narrow corridors composed of frequently flooded mature forests and complemented by afforested younger forest patches due to BLH afforestation efforts. Sylvilagus aquaticus (Swamp Rabbit), a BLH forest-specialist species, require a diversity of habitat conditions, but little information exists on fine-scale Swamp Rabbit use of mature and young forest habitats and the conditions that may influence Swamp Rabbit habitat use. We addressed this literature gap by assessing use of habitat by Swamp Rabbits in afforested and mature BLH stands in southern Illinois during March 2014–March 2016. At 746 plots (area = 3.15 m2, 60 m x 60 m spacing), we used Swamp Rabbit fecal pellets to quantify Swamp Rabbit habitat use and identified 9 habitat variables known to be important to Swamp Rabbits. We then created 18 a priori generalized linear models to evaluate variation in Swamp Rabbit habitat use relative to habitat variables each study year. Individual forest stands strongly influenced Swamp Rabbit habitat use in all 3 study years in addition to macro-habitat variables (i.e., distance to water, distance to afforested–mature stand interface) and micro-habitat variables (i.e., woody stem density, herbaceous ground cover) in some years. We found that both mature and afforested stands were used by Swamp Rabbits but that edaphic conditions specific to stands likely affected flooding and water inundation in localized areas impacting habitat conditions and thus Swamp Rabbit use. While we found increased ground vegetation and woody stem density had positive impacts on habitat use by Swamp Rabbits in 2014, these variables were no longer significant predictors of Swamp Rabbit occupancy when flooding was severe in 2015 and the following year, 2016. These results point towards water inundation from flooding as the main driver of Swamp Rabbit habitat use when it limits terrestrial habitat and the availability of vegetation resources important for food and hiding cover. Because Swamp Rabbit habitat use is driven by habitat at the stand scale, habitat management can focus on managing stands with more consistently dry conditions to provide all necessary habitat elements when lower elevations are unavailable due to inundation. This research underscores the annual variability of these forest ecosystems and the importance of incorporating forest vegetation dynamics, hydrogeomorphology and flooding incidence and severity into management plans for Swamp Rabbits.
Mountain streams with rocky substrates and high turbulence are generally characterized by bryophytes rather than vascular plants. Conocephalum salebrosum (Snakeskin Liverwort) is a thallose bryophyte that occurs in damp soil along streambanks as well as on rocks and boulders in stream channels. Our objectives were to determine its prevalence on boulders in western North Carolina streams and characterize its habitat and chlorophyll levels. We documented Snakeskin Liverwort in 11 streams across 6 counties and 3 river basins; all had a circumneutral pH and low conductivity. We found patches of Snakeskin Liverwort in a variety of light conditions, but overall, patches were situated on boulders that received significantly less sunlight than nearby random boulders. Within channels, patches occurred more often along the edges of streams than in the center. Chlorophyll concentrations in thalli collected from 2 streams at different elevations and river basins did not differ significantly, suggesting similar photosynthetic potential. Mosses were present on ≥92% of boulders supporting Snakeskin Liverwort and on ≥90% of nearby random boulders. Vascular plants occurred in 50–93% of Snakeskin Liverwort patches, compared with 10–28% of random boulders. Graminoids (sedges and grasses) were the most common vascular plants aasociated with liverwort patches, followed by forbs. Our results suggest the thallose mats of Snakeskin Liverwort facilitate the establishment of rooted plants on boulders, which could enhance overall primary production in mountain streams.
Sherman traps are widely used in ecological studies to live-trap small mammals. However, confinement in traps can expose captures to potentially lethal temperatures, especially in warm climates and seasons. We assessed several strategies to mitigate excessive heating in Sherman traps, including trap perforations, reflective paint, insulation, and shade (with and without conduction between shading materials and the trap). We measured maximum internal trap temperatures and the duration of temperatures above 35 °C (a temperature likely to endanger small mammals in our region) and compared the effectiveness of the cooling strategies. All strategies except perforations kept maximum internal temperatures significantly cooler than control traps, and cover which provided shade without conduction had the lowest maximum temperature. All strategies except perforations and shade with conduction significantly shortened the duration over which trap temperatures were above 35 °C, and traps under shade without conduction provided the best protection. Our results provide information which can help trappers avoid accidental mortality and consequences associated with heat stress.
Pinus spp. (pine) forests are common throughout the southeastern US, and many of these forests are managed to improve habitat for Odocoileus virginianus (White-tailed Deer) and Meleagris gallopavo (Wild Turkey). Previous studies have investigated the influence of forest management on deer and turkey habitat, but several aspects of understory vegetation response to management are not well understood. We measured understory composition and structure, overstory basal area, and deer-forage availability at 8 sites in summer 2020. Previous history of dormant-season fire increased grass and decreased vine coverage, but forb and understory tree coverage were not influenced. Vegetation providing visual obstruction for turkey nesting and deer fawning was correlated with increased coverage of semiwoody and woody plants. Forb coverage averaged 14% and was positively correlated with deer nutritional carrying capacity (NCC) using a 14% protein constraint. Conversely, NCC with a 6% protein constraint correlated with shrub and vine coverage. Sunlight available to the understory was most strongly influenced by hardwood overstory and midstory trees. Our results indicate that understory composition strongly influences forage and cover and that pine stands that are not intensively managed generally provided limited resources for deer and turkeys.
Grus americana (Whooping Crane) are particularly susceptible to colliding with power lines due to their wing loading, size, and flight behavior, often resulting in fatal collisions. This is the first study assessing the specific biological (sex, age, flock size), environmental (time of year, time of day), and structural (line type, line direction) circumstances associated with Whooping Crane collisions with power lines in all 4 reintroduced populations. We documented 65 instances of mortality from power lines and found that both migratory and nonmigratory reintroduced populations were at risk. In migratory populations, collisions seemed more likely to occur during migration. Significantly more males collided with power lines than females in nonmigratory populations. Both transmission and distribution lines posed threats for collisions in all populations. We documented more collisions of juvenile and sub-adult cranes than adults. This study aims to provide insight into the circumstances in which power lines pose a threat to cranes, which will inform efforts to mark power lines and guide decisions on release locations for captive-reared cranes, in hopes of ultimately reducing mortalities and improving population growth for reintroduced Whooping Cranes.
Marshallia legrandii (Oak Barrens Barbara's-buttons) is a critically imperiled perennial herb in North Carolina and Virginia's Piedmont region. We completed a flowering census of this species at 2 of its 3 known populations in 2021, and again at the largest of those measured populations in 2022. We compared flowering density with canopy openness at both sites. At the largest population, we also measured competing vegetation, soil properties, and Oak Barrens Barbara's-buttons density to describe its habitat. Here, we also implemented an experimental augmentation of Oak Barrens Barbara's-buttons to monitor planting survival and growth under different light environments. We found that Oak Barrens Barbara's-buttons can flower under a broader range of canopy openness than previously believed. In addition to light, we found that competing vegetation, soil temperature, and soil moisture are important predictors of flowering success. Survival of augmented Oak Barrens Barbara's-buttons was nearly 90%, and 28–42% of plants bloomed 2 years after planting.
Etheostoma punctulatum (Stippled Darter) was recently redescribed to recognize 2 additional species, E. autumnale (Autumn Darter) and E. mihileze (Sunburst Darter), as part of the E. punctulatum species complex. This taxonomic update rendered the collection of Stippled Darters in the Arkansas Tech Fish Collection (ATFC) inaccurate since the stored specimens were collected well before and just after the redescriptions. Upon reassessment, we found that the ATFC did not contain any specimens now considered as Stippled Darters but, instead, contained specimens of the 2 newly described species and misidentified Nothonotus juliae (Yoke Darter). We concluded that the collection consisted of 54 Autumn Darters, 96 Sunburst Darters, and 220 Yoke Darters. Additionally, external quantitative and qualitative characteristics did not exactly follow the expected trends as laid out in the study that described the new species. This study serves as a small, but clear, example of the importance of curating and updating natural history collections like that of the ATFC, for they play a vital role in a number of different areas of study including biogeographic range changes, phenological shifts, evolutionary changes, and more.
The Fungal, Lichen, and Myxomycete Collections of the University of North Carolina (UNC) at Chapel Hill Herbarium (NCU) contain 952 type specimens, representing 607 names, which, based on current taxonomy and nomenclature, amount to 596 unique taxa. This wealth of type specimens is a legacy of the taxonomic research on fungi conducted by William C. Coker, Alma Holland Beers, John N. Couch, and other UNC mycologists in the first half of the 20th century. This inventory is a compilation of these types plus specimens for invalidly published designations that were intended as types by the mycologists who worked on these specimens. Also included are original material specimens intended as types for taxa in invalid publications, which were not included in the publications by subsequent authors validating the taxa. Fungal groups particularly well represented in the types held at NCU are boletes, clavarioid fungi, gasteroid fungi, hydnoid fungi, and septobasidia. A lectotype is designated for Clavaria atroumbrina. Since 2014, more than 1000 collections including >100 types have been loaned by NCU to mycologists at institutions around the world.
Etheostoma striatulum (Striated Darter) is an increasingly rare darter found in the middle-to-upper regions of the Duck River watershed in Tennessee. This rarity, coupled with a lack of collection and sampling, has put them in review for listing under the Endangered Species Act. Because of the Striated Darters' reclusive and cryptic behavior, conventional techniques tend to be less effective for detection, requiring more precise and sensitive methods. To provide information regarding distribution and occupancy within the Duck River, we used molecular detection of species-specific environmental DNA to test for presence of the species at historical sampling sites. Assessments indicate that Striated Darter is persisting in all tributaries of historical occurrence, with the addition of 4 new tributaries. However, given that 16 sites produced positive signals for less than a third of qPCR replicates, it appears that 60% of these populations are persisting at low detection levels. Detection was positively correlated with turbidity, which could be explained by their preference for lower-velocity habitats. Our results will assist with identifying critical-habitat locations for the update on the status of Striated Darter while also aiding in the standardization of eDNA-assay development for rare and cryptic species.
Etheostoma fonticola (Fountain Darter) is federally listed as endangered and endemic to a single river basin in Texas, occupying stenothermal headwaters (22–23°C) of the spring-influenced San Marcos River and Comal River. Reported distribution is limited to the upper 6.4 river kilometers (rkm) of the San Marcos River, but a collection of a Fountain Darters farther downstream (11.5 rkm from the headwaters) in August 2022, along with visual observations of other small percids in the immediate area, prompted a preliminary assessment to document extent of the Fountain Darter's downstream distribution. Using seines to target mesohabitats (i.e., riffle, run, pool, backwaters) likely to contain Fountain Darters, we resampled the same site as the 2022 collection in April 2023 to assess overwinter survival. In June 2023, we sampled 5 sites located 10.2–19.0 rkm downstream from the headwaters. Between both sampling dates, we collected 243 Fountain Darters among 13 mesohabitats at 3 sites located 10.2–16.0 rkm downstream from the headwaters, including a mesohabitat with water temperatures reaching 29 °C. The occurrence and abundance of Fountain Darters in a reach of the San Marcos River within a more eurythermal environment offer a unique opportunity to assess population viability of Fountain Darters outside of a stenothermal environment, which in the past was considered to be a primary limiting factor in wider distributions of Fountain Darters.
Etheostoma parvipinne (Goldstripe Darter) is an ecologically enigmatic percid native to lowland streams in the coastal plain of the southeastern United States. Our observations from 6 separate localities across Alabama suggest that Goldstripe Darters seasonally move from resident stream habitats to isolated seepages and vernal pools to spawn. Specifically, at 6 separate sites in Alabama we documented Goldstripe Darters inhabiting and reproducing in isolated seasonal pools and semi-isolated seeps with other vernal pool spawners including mole salamanders (Ambystoma spp.). Notably, some vernal pools used by Goldstripe Darters for reproduction were located >100 m away from the nearest creek with no observed aquatic connection or atop incised stream banks several meters tall. Similar behaviors have been documented in some members of the revised clade Psychromaster and Etheostoma trisella (Trispot Darter), which are listed as special concern, threatened, or endangered by federal and state agencies. While the Goldstripe Darter was previously hypothesized to spawn in seasonal floodplain and spring seepage habitats, we are the first to document this behavior; however, it is not yet clear if this behavior is range wide. Our observations will have implications on the understanding of the evolution of complex reproductive life histories in the North American darters.
This article is only available to subscribers. It is not available for individual sale.
Access to the requested content is limited to institutions that have
purchased or subscribe to this BioOne eBook Collection. You are receiving
this notice because your organization may not have this eBook access.*
*Shibboleth/Open Athens users-please
sign in
to access your institution's subscriptions.
Additional information about institution subscriptions can be foundhere