23 research outputs found
Aspects of Distribution, Abundance, Habitat, and Life History of the Caddo Madtom (\u3ci\u3eNoturus taylori\u3c/i\u3e), a Narrow Endemic of the Ouachita Highlands
The Caddo Madtom, Noturus taylori, is a small catfish endemic to the Ouachita Mountain ecoregion in Arkansas, with habitat altered by land use practices and reservoir dams. We examined aspects of distribution, abundance, habitat, and life history of N. taylori during seasonal sampling from winter 2016 through fall 2017. Our sampling data were concordant with previous studies that suggested N. taylori is more widespread and has higher catch per unit effort in the Caddo River drainage when compared to the upper Ouachita River drainage. We did not detect N. taylori in the Little Missouri River drainage, where it is presumed extirpated. A total of 370 individuals ranging from 14–76 mm (mean = 45.1 mm) standard length (SL) were collected during seasonal samples. Length-frequency analyses estimated a maximum age of 3 years for N. taylori, and we identified three discernable age classes with the emergence of young-of-year (age 0 cohort) in summer: age 0 (up to ~40 mm SL); age 1 (~41-60 mm SL); and age 2+ (\u3e60 mm SL). Sites where N. taylori was captured had an average depth of 20.6 cm, an average base velocity of 0.18 m/sec, and were dominated primarily by a mix of gravel, pebble, and cobble. Despite the relatively higher abundances of N. taylori in the Caddo River, we recommend that long-term, periodic monitoring of N. taylori would be an important conservation tool to assess potential future changes in distribution, habitat, occurrence, and abundance. Future studies that implement occupancy and habitat suitability modeling are needed to better understand suitable and preferred habitat of N. taylori
Disturbance and Recovery of Salt Marsh Arthropod Communities following BP Deepwater Horizon Oil Spill
Oil spills represent a major environmental threat to coastal wetlands, which provide a variety of critical ecosystem services to humanity. The U.S. Gulf of Mexico is a hub of oil and gas exploration activities that historically have impacted intertidal habitats such as salt marsh. Following the BP Deepwater Horizon oil spill, we sampled the terrestrial arthropod community and marine invertebrates found in stands of Spartina alterniflora, the most abundant plant in coastal salt marshes. Sampling occurred in 2010 as oil was washing ashore and a year later in 2011. In 2010, intertidal crabs and terrestrial arthropods (insects and spiders) were suppressed by oil exposure even in seemingly unaffected stands of plants; however, Littoraria snails were unaffected. One year later, crab and arthropods had largely recovered. Our work is the first attempt that we know of assessing vulnerability of the salt marsh arthropod community to oil exposure, and it suggests that arthropods are both quite vulnerable to oil exposure and quite resilient, able to recover from exposure within a year if host plants remain healthy
"Says Kabir": Unbounded sounds
Kabir, the weaver-poet, has continued to permeate many facets of Indian society since his life in the fifteenth century. The poetry attributed to him is a large body of work existing in oral, print, recording, and other forms that encompasses much more today than what Kabir said in his lifetime. Between the biting social criticisms and intimate devotional messages, the poetry bridges many ideological gaps, ensuring its longevity. Through fieldwork across India, I came to understand Kabir as a musical tradition, rooted in poetry, that continually renews its sonic character to speak to new generations while maintaining a heterogeneous variety of styles (folk, classical, semi-classical, and more). Predominantly studied previously as a text-based tradition, a focus on the range of musical styles and content that Kabir encompasses enables us to understand its popularity across religious, socioeconomic, and generational divisions and provides insights into Kabir's place in today's North Indian society
Stability at Low Densities or Endangered? Spatiotemporal Population Dynamics of the Caddo Madtom (Noturus taylori)
Imperilment in North American freshwater fishes is primarily due to habitat alteration, deterioration, and fragmentation. In response to the aquatic biodiversity crisis, there has been a call for action by the Center for Biological Diversity, with a petition for the federal listing of 404 aquatic species in the southeastern U.S. This thesis focuses on a petitioned species, the Caddo Madtom, Noturus taylori. The chapters in this thesis address the genetic variation, habitat limitations, and status of the Arkansas endemic. In summation, N. taylori was found to have a high level of genetic variation for an endemic madtom, and is relatively abundant throughout its distribution range. Additionally, N. taylori was found to exhibit variable habitat association within and among the drainages it inhabits. These data will provide an updated status for federal and state agencies for N. taylori, which will be informative for listing and conservation management decisions for the species
COMMUNITY ECOLOGY -ORIGINAL RESEARCH Geographic variation in salt marsh structure and function
Abstract We examined geographic variation in the structure and function of salt marsh communities along the Atlantic and Gulf coasts of the United States. Focusing on the arthropod community in the dominant salt marsh plant Spartina alterniflora, we tested two hypotheses: first, that marsh community structure varies geographically, and second, that two aspects of marsh function (response to eutrophication and addition of dead plant material) also vary geographically. We worked at eleven sites on the Gulf Coast and eleven sites on the Atlantic Coast, dividing each coast up into two geographic areas. Abiotic conditions (tidal range, soil organic content, and water content, but not soil salinity), plant variables (Spartina nitrogen content, height, cover of dead plant material, but not live Spartina percent cover or light interception), and arthropod variables (proportional abundances of predators, sucking herbivores, stem-boring herbivores, parasitoids, and detritivores, but not total arthropod numbers) varied among the four geographic regions. Latitude and mean tidal range explained much of this geographic variation. Nutrient enrichment increased all arthropod functional groups in the community, consistent with previous experimental results, and had similar effects in all geographic regions, contrary to our hypothesis, suggesting widespread consistency in this aspect of ecosystem function. The addition of dead plant material had surprisingly little effect on the arthropod community. Our results caution against the uncritical extrapolation of work done in one geographic region to another, but indicate that some aspects of marsh function may operate in similar ways in different geographic regions, despite spatial variation in community structure
Typical conditions at oiled sites.
<p>At the leading edge of the marsh, there was C) a zone up to 5 m wide of bare mud where all vegetation had died. Behind this was B) a zone of wrack up to 2 m wide consisting of heavily-oiled plant debris. Behind this was A) an extensive zone of live and apparently healthy <i>Spartina alterniflora</i>. Oil sheens were visible on the soil surface within the live <i>Spartina</i> zone. At some oiled sites, the dead zone and wrack line were absent, but oil sheens were visible within the live <i>Spartina</i> zone. Sampling at both oiled and control sites was done at least 2 m inside the live <i>Spartina</i> zone.</p
Measurements of soil and vegetation at oiled and control sites (means ± SE).
<p>Data were analyzed with ANOVA; p-values for the main effects of oil and year, and their interaction, are shown.</p
Densities of marine invertebrates and terrestrial arthropods at oiled and control sites in 2010 and 2011.
<p>A) <i>Littoraria</i> m<sup>−2</sup>; B) crab burrows m<sup>−2</sup>; C) total terrestrial arthropods 0.56 m<sup>−2</sup> (not including crustaceans); D) predators 0.56 m<sup>−2</sup>; E) sucking herbivores 0.56 m<sup>−2</sup>; F) stem-boring herbivores 0.56 m<sup>−2</sup>; G) parasitoids 0.56 m<sup>−2</sup>; and H) detritivores 0.56 m<sup>−2</sup>. Open bars indicate control sites; filled bars indicate oiled sites. Data are means ±1 SE.</p
Summary of ANOVA results (d.f., F statistics, and p-values) for invertebrate groups.
<p>Sample sizes are as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032735#pone-0032735-t001" target="_blank">Table 1</a>. Asterisks indicate variables that were natural log transformed before analysis.</p
A multi-site randomized clinical trial to reduce suicidal ideation in suicidal adult outpatients with Major Depressive Disorder: Development of a methodology to enhance safety
BACKGROUND/AIMS: Suicide is a major public health concern, yet there are very few randomized clinical trials that have been conducted to reduce suicidal ideation in patients at risk for suicide. We describe the rationale and refinements of such a trial that is designed to assess the effect of a hypnotic medication on suicidal ideation in adult outpatients currently experiencing suicidal ideation. METHODS: “Reducing Suicidal Ideation Through Insomnia Treatment (REST-IT)” is a multi-site randomized clinical trial that includes 3 recruiting sites and one data management site. This 4-year study is in its second year of recruitment. The purpose of the study is to compare hypnotic medication versus placebo as an add-on treatment to a selective serotonin reuptake inhibitor as a means of reducing suicidal ideation in depressed adult outpatients with insomnia and suicidal ideation. The safety features of the study follow the 2001 NIH guidelines for studies that include patients at risk of suicide. RESULTS: Five hundred and eighty-four potential participants have undergone telephone screening; 67% of these failed the phone screen, most often due to an absence of expressed suicidal ideation (26% of the telephone screen fails). One hundred and twelve persons appeared for a face-to-face baseline assessment, and 40 of these had completed a taper of their ineffective psychotropic medications before the baseline assessments. Sixty-four% of those who completed baseline assessments failed to proceed to randomization, most commonly because of no clinically significant suicidal ideation (51% of those excluded at baseline). One participant was offered and accepted voluntary psychiatric hospitalization in lieu of study participation. Thus far, 40 participants have been randomized into the study, 88.7% of scheduled visits have been attended, with 93.8% adherence for the SSRI and 91.6% adherence for the randomized hypnotic versus placebo. None of the randomized participants have required hospitalization or had a suicide attempt. CONCLUSIONS: By carefully considering the inclusion and exclusion criteria and other safety features, the safe conduct of randomized clinical trials in suicidal adult patients is possible, including the inclusion of participants who have undergone a prescribed tapering of psychotropic medications prior to baseline assessment