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.
Although aberrant coloration is known to occur in mammals, few records of the phenomenon exist in the literature for North American bats. Here we report on 2 leucistic Perimyotis subflavus (Tri-colored Bats) in Leon County, TX, that had a distinct white patch on their bodies. Our observation is the third documentation of leucism in Tri-colored Bats.
The seed germination ecology of Calycanthus floridus (Eastern Sweetshrub) has not been formally investigated. The purposes of this study were to determine the type of seed dormancy found in the species, the most effective method of breaking this dormancy, and the environmental conditions producing maximum germination. We employed a variety of standard treatments to determine the specific type(s) of dormancy present, as well as treatments to determine effective dormancy-breaking mechanisms. We determined that seeds possessed physical dormancy (PY) imposed by a water-impermeable seed coat. Mechanical scarification was the most effective method of breaking PY; submersion in acid was also moderately effective. Seed germination following scarification can occur over a wide range of temperatures. There is no light requirement for seed germination. This study represents the first case of physical dormancy reported for the genus and only the second for the family.
We used grasshoppers as a model organism to examine the response of prey to repeated approach from a persistent predator (human observer). We randomly assigned adult Chortophaga australior (Southern Greenstriped Grasshopper) to either low- or highrisk treatments. For both groups, we approached each grasshopper during 15 consecutive encounters and recorded the distance fled (DF) and overall flight path. We approached grasshoppers assigned to the low-risk treatment after a 30-second delay upon landing between each escape flight. Those in the high-risk treatment were approached immediately upon landing and given no opportunity to recover. Grasshoppers assigned to the low-risk treatment exhibited an erratic, or protean flight path to evade detection and traveled shorter distances across consecutive encounters. Those in the high-risk treatment exhibited longer escape flights that were more commonly oriented directly away from the approach of the observer. The results of our study provide additional evidence that prey may shift escape strategies in response to real-time assessment of predation risk.
Sayornis phoebe (Eastern Phoebe) has expanded its breeding range southeasterly at water-based anthropogenic structures along forested streams in the Pee Dee region of South Carolina. Its current range is truncated in the Upper Coastal Plain, 31–35 km below the lower boundary of the Sandhills subregion (Orangeburg Scarp). The predominance in the Upper Coastal Plain of South Carolina of structures that are less suitable for nesting by Eastern Phoebes (e.g., small bridges without ledges, box culverts), in contrast to preferred structures (i.e., small bridges with ledges) available upriver in the Sandhills and eastern Piedmont of North Carolina, has not limited their colonization (∼2 km y-1 since ca. 1990). This breeding-range expansion is consistent with a correlative ecological-niche model (ENM) prediction that the Eastern Phoebe is expanding its breeding range in the Pee Dee region across a broad front toward the SC coast. This breeding-range expansion, with a slight drop in latitude and elevation, has been slower than the contemporary expansion of Petrochelidon pyrrhonota (Cliff Swallow) in the same direction in the same region. Hirundo rustica (Barn Swallow) uses water-based anthropogenic structures, but has also widely colonized land-based structures during its faster past breeding range-expansion into the Pee Dee region. Differences in the number, size, and suitability of water-based anthropogenic structures used by these 3 species suggest additional constraints that influence the colonization rate and population size of Eastern Phoebes.
From 2004 to 2006, we used a variety of sampling techniques to survey the amphibians of Savannah National Wildlife Refuge (SNWR), a large protected area straddling the lower portions of the Savannah River on the border between South Carolina and Georgia. We documented 22 amphibian species—15 frogs and 7 salamanders—with a possible 23rd species present. Species richness was lower than what might be expected from amphibian field guides of species inhabiting the adjacent Coastal Plain, likely due to a lack of specialized habitats, such as temporary ponds and upland pine forest. Amphibians occupied a variety of habitats and appeared tolerant of the mildly acidic and low-oxygen conditions of many of the wetlands. Although additional species may be found at SNWR, this initial survey provides a historic baseline for monitoring amphibian populations as areas adjacent to the refuge are disturbed, the climate changes, and multi-use management objectives are implemented within refuge boundaries.
The relationships between environmental variables and the growth rates of fishes are important and rapidly expanding topics in fisheries ecology. We used an informationtheoretic approach to evaluate the influence of lake surface area and total phosphorus on the age-specific growth rates of Lepomis macrochirus (Bluegill) in 6 small impoundments in central Georgia. We used model averaging to create composite models and determine the relative importance of the variables within each model. Results indicated that surface area was the most important factor in the models predicting growth of Bluegills aged 1–4 years; total phosphorus was also an important predictor for the same age-classes. These results suggest that managers can use water quality and lake morphometry variables to create predictive models specific to their waterbody or region to help develop lake-specific management plans that select for and optimize local-level habitat factors for enhancing Bluegill growth.
Vireo atricapilla (Black-capped Vireo) is an endangered songbird whose habitat use has been well studied in central portions of its breeding range, which is characterized by successional vegetation communities. To expand our understanding of habitat use as it relates to reproductive success, we studied Black-capped Vireo habitat use at the territory and nest-site scales in southwest Texas in 2009 and 2010, an area characterized by xeric and stable vegetation communities. We measured vegetation in territories and at nests to evaluate the influence of habitat variables on nest parasitism and nest survival. Our results showed that Black-capped Vireo nest-site use in southwest Texas differed from that in breeding areas of central Texas and Oklahoma. Black-capped Vireos in southwest Texas used nest sites with a wide range of woody cover (70 ± 13%) and used Juniperus spp. (junipers) as a nest substrate proportionately more than its availability in territories, which is contradictory to previously published literature. Nest parasitism increased significantly with greater nest height, likely due to increased visibility to Molothrus ater (Brown-headed Cowbird). Increasing height of vertical cover above the nest was associated with decreased overall nest survival, likely because nests placed in habitat with taller vegetation are more susceptible to avian predators and Brown-headed Cowbird parasitism. Unlike the findings of studies conducted in the northern part of the species' breeding range, we found that parasitism did not increase the likelihood of depredation or abandonment. Our results indicate that Black-capped Vireo habitat structure and composition, as well as factors influencing nest success in Southwest Texas, differ from their breeding habitat in central Texas and Oklahoma, indicating that management guidelines need to be regi on-specific.
We compared water-quality effects of 13 beaver ponds on adjacent free-flowing control reaches in the Coastal Plain of rural North Carolina. We measured concentrations of nitrate, ammonium, soluble reactive phosphorus (SRP), and suspended sediment (SS) upstream and downstream of paired ponds and control reaches. Nitrate and SS concentrations decreased, ammonium concentrations increased, and SRP concentrations were unaffected downstream of the ponds and relative to the control reaches. The pond effect on nitrate concentration was a reduction of 112 ± 55 μg-N/L (19%) compared to a control-reach—influenced reduction of 28 ± 17 μg-N/L. The pond effect on ammonium concentration was an increase of 9.47 ± 10.9 μg-N/L (59%) compared to the control-reach—influenced reduction of 1.49 ± 1.37 μg-N/L. The pond effect on SS concentration was a decrease of 3.41 ± 1.68 mg/L (40%) compared to a control-reach—influenced increase of 0.56 ± 0.27 mg/L. Ponds on lower-order streams reduced nitrate concentrations by greater amounts compared to those in higher-order streams. Older ponds reduced SS concentrations by greater amounts compared to younger ponds. The findings of this study indicate that beaver ponds provide water-quality benefits to rural Coastal Plain streams by reducing concentrations of nitrate and suspended sediment.
Geomys personatus maritimus (Maritime Pocket Gopher) is a genetically distinct subspecies of pocket gopher that occurs only in deep, sandy soils located in Nueces and Kleberg counties of southern Texas. The US Fish and Wildlife Service considers it a species of concern. Pocket gophers are considered a nuisance because they dig burrows and create mounds in landscaped areas. Lethal control options are not advised because of the Maritime Pocket Gopher's rarity status and recent public attitude disfavoring lethal methods. However, short-distance translocation might be a management option, but research to determine its viability is lacking. We captured 15 Maritime Pocket Gophers from athletic fields and commercial properties in Corpus Christi, TX. For all captured gophers, we subcutaneously or intraperitoneally implanted a radio transmitter, translocated the animals to private property within 2 km from their capture site, and radio-tracked their movements for ≤⃒4 months to determine if their behavior and activity differed from 4 control gophers. Subcutaneous transmitters implanted in the scapular region were lost by 86% of the gophers (n = 12 of 14), while 100% (n = 5) of the gophers retained intraperitoneal-implanted transmitters. Relocated Maritime Pocket Gophers did not return to their site of origin. Gopher movements generally were away from their homing lines (i.e., an imaginary line drawn between each translocated gopher's capture site and release site), and they did not become successively closer to their respective sites of capture. Therefore, short-distance translocation has the potential to be a management option for nuisance gophers.
Sylvilagus aquaticus (Swamp Rabbit) is an imperiled species in Missouri that inhabits highly fragmented bottomland forested habitats in the southeastern portion of the state. Between 2010 and 2012, we conducted repeated, extensive presence—absence winterlatrine surveys in 15 counties to document their distribution. We compared our results to those of 2 previous winter-latrine surveys (2001–2002 and 1991–1992) conducted at the same sites. In addition, we used the Program MARK to estimate detection probability and site occupancy, and evaluate the influence of survey-site size on detectability and occupancy, and temperature at the time of the survey on detectability. We located 264 of 278 survey sites that were first surveyed in 1991, but could only survey 211. We detected Swamp Rabbits at 144 of 211 sites in 12 counties yielding a naïve occupancy estimate of 0.68. This estimate was higher than reported by both previous surveys: 0.53 in 2001–2002 and 0.40 in 1991–1992. Using occupancy modeling for the 2010–2012 survey, the estimated detection probability was 0.89 (SE = 0.02) and site occupancy was 0.70 (SE = 0.03). As expected, the size of a survey site influenced both detectability of and occupancy by Swamp Rabbits, and temperature influenced detectability. As the size of a site increased, both detectability and occupancy increased, and detectability increased as temperature decreased. Swamp Rabbits continue to occur in 13 counties and occupy fragmented, sometimes isolated blocks of bottomland forested habitat across the Mississippi River Alluvial Basin and along some Ozark Highlands streams.
We attempted to determine cross-shelf, diel, and seasonal distribution patterns of paralarval cephalopods off eastern Florida during a 5-year study that employed both open-net and discrete-depth closing-net sampling. Based on our 303 samples, abundant and common squid taxa included the squid Doryteuthis spp., which tended to be in coastal and intermediate waters, and Abralia cf veranyi (Eye-Flash Squid), Illex spp. (shortfin squid), and Ommastrephidae Type A (which could include Ommastrephes bartramii [Neon Flying Squid] and Ornithoteuthis antillarum [Atlantic Bird Squid]), mostly in intermediate and Florida Current waters. Species diversity and abundance were usually greatest in Florida Current waters versus coastal and intermediate waters. Overall, however, few patterns were obvious from these samples. Accessory sampling to examine variability indicated that a large number of samples are required to infer detailed distribution patterns. We also found that the difference in variation between sampling at a fixed location and sampling within a moving parcel of water was not consistent.
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