Local and landscape scale factors influencing edge effects on woodland salamanders

We examined local and landscape-scale variable influence on the depth and magnitude of edge effects on woodland salamanders in mature mixed mesophytic and northern hardwood forest adjacent to natural gas well sites maintained as wildlife openings. We surveyed woodland salamander occurrence from June-August 2006 at 33 gas well sites in the Monongahela National Forest, West Virginia. We used an information-theoretic approach to test nine a priori models explaining landscape-scale effects on woodland salamander capture proportion within 20 m of field edge. Salamander capture proportion was greater within 0-60 m than 61-100 m of field edges. Similarly, available coarse woody debris proportion was greater within 0-60 m than 61-100 m of field edge. Our ASPECT model, that incorporated the single variable aspect, received the strongest support for explaining landscape-scale effects on salamander capture proportion within 20 m of opening edge. The ASPECT model indicated that fewer salamanders occurred within 20 m of opening edges on drier, hotter southwestern aspects than in moister, cooler northeastern aspects. Our results suggest that forest habitat adjacent to maintained edges and with sufficient cover still can provide suitable habitat for woodland salamander species in central Appalachian mixed mesophytic and northern hardwood forests. Additionally, our modeling results support the contention that edge effects are more severe on southwesterly aspects. These results underscore the importance of distinguishing among different edge types as well as placing survey locations within a landscape context when investigating edge impacts on woodland salamanders.     

Residential Indoor,Outdoor, and Workplace Concentrations of Carbonyl Compounds: Relationships with Personal Exposure Concentrations and Correlation with Sources

Abstract

Personal 48-hr exposures of 15 randomly selected participants as well as microenvironment concentrations in each participant’s residence and workplace were measured for 16 carbonyl compounds during summer–fall 1997 as a part of the Air Pollution Exposure Distributions within Adult Urban Populations in Europe (EXPOLIS) study in Helsinki, Finland. When formaldehyde and acetaldehyde were excluded, geometric mean ambient air concentrations outside each participant’s residence were less than 1 ppb for all target compounds. Geometric mean residential indoor concentrations of carbonyls were systematically higher than geometric mean personal exposures and indoor workplace concentrations. Additionally, residential indoor/outdoor ratios indicated substantial indoor sources for most target compounds. Carbonyls in residential indoor air correlated significantly, suggesting similar mechanisms of entry into indoor environments. Overall, this study demonstrated the important role of non-traffic-related emissions in the personal exposures of participants in Helsinki and that comprehensive apportionment of population risk to air toxics should include exposure concentrations derived from product emissions and chemical formation in indoor air.     

Community vulnerability and resilience in disaster risk reduction: an example from Phojal Nalla,Himachal Pradesh,India

International Disaster Risk Reduction Frameworks and Indian Plans advocate shared responsibility for reducing disaster risk, in which community vulnerability and resilience conditions are central. This paper presents a case study from the Indian Himalaya (Kullu District) of community vulnerability and resilience conditions following damaging floods, primarily the 1994 Phojal Nalla flood, through the concepts of community heritage and capital. Data were collected in the period 2013–2016, using semi-structured interviews (n?=?129), village reconnaissance and archival/contemporary data searches. The connections between heritage, capital, vulnerability and resilience are complex, but results demonstrate ‘knowledge’ is the principal driver of resilience conditions, via facets of heritage (e.g. religious infrastructure and activities, traditional architectural vernacular, and multi-generational attachments to place) and capital (e.g. income diversification, access to communication technologies, societal welfare measures and positive interactions with water). Persisting vulnerabilities stem from differential access to and implementation of best practice knowledge, governed by social, economic and political conditions. Further improvements in risk reduction require greater consideration of the following: (1) the integration of community local knowledge into the overall disaster management process; (2) the opportunities offered by mobile phone and other technologies for generating and sharing knowledge across society; and (3) the value of under-utilised knowledge of past disaster events, assembled from a systematic evaluation of oral, documentary and landscape evidence, to risk reduction.     

An Investigation Into the Mechanism by Which Synthetic Zeolites Reduce Labile Metal Concentrations in Soils

The addition of synthetic zeolites and similar materials to metal contaminated soils has been shown to reduce soil phytotoxicity and to improve the quality of plant growth on such amended soils. To gain an understanding of the mechanism by which the phytotoxicity of contaminated soils is reduced when treated with synthetic zeolites, sequential extraction procedures and soil solution techniques have been used to identify changes associated with metal speciation in amended soils. Sequential extraction data and changes in soil solution composition are presented for three different contaminated soils, amended with three synthetic zeolites (P, 4A and Y) at concentrations of 0.5%, 1% and 5% w/w, or lime at 1%. The soils were collected from the site of a metal refinery, an old lead zinc mine spoil tip and from a field which had been treated with sewage sludge. After incubation of the zeolite treated soils for between one and three months, results showed a reduction in the metal content of the ammonium acetate fraction between 42% and 70%, depending on soil, zeolite and rate of addition, compared with the unamended soils. In addition, soil solution experiments indicated that synthetic zeolite amendments were more efficient at reducing metal content than comparable lime treatment. The mechanism by which synthetic zeolites reduce metal bioavailability in contaminated soils is discussed and compared to other amendments.     

Methane Fluxes from a Wetland using the Flux-Gradient Technique The Measurement of Methane Flux from a Natural Wetland Pond and Adjacent Vegetated Wetlands using a TDL-Based Flux-Gradient Technique

Methane emissions were measured from a bog andlake in the Experimental Lakes Area in Northern Ontario in 1992and 1993, prior to and following flooding. Bog fluxes were smallin 1992 (0.27 mg m^-2 d^-1) but increased 5-fold in 1993 afterflooding. Over the bog, there was a diel cycle of nighttimeemission and daytime uptake in 1992 in contrast to constantemission in 1993. Lake emissions decreased after flooding butwere much greater than bog emissions in both years (average = 7.3 mg m^-2 d^-1). Seasonally, the bog flux was correlated withground temperatures after flooding. In 1992, lake fluxes werecorrelated with air temperature on a daily basis. In contrast,seasonal lake fluxes were correlated with water and sedimenttemperatures in 1992, but only with sediment temperatures in1993. These results are explained with respect to the effects offlooding on lake and bog dynamics.     

Optimising the timing for nuchal translucency measurement

It appears from current evidence that the most effective screening strategy for Down syndrome will involve a combination of first trimester nuchal translucency and serum biochemistry, whether performed in the first or second trimester. The aim of this study was to determine the optimum gestation based upon menstrual dates at which to schedule nuchal translucency (NT) measurement for the evaluation of fetal Down syndrome risk. Five thousand eight hundred and thirty-five pregnancies had an ultrasound scan scheduled between 11 and 14 completed weeks of gestation based upon either the last menstrual period (n = 3199) or a prior ultrasound scan (n = 2636). For last menstrual period-based ultrasound scans, with advancing gestation the frequency of missed miscarriage significantly decreased (p = 0.009, chi squared test), as did the need to reschedule a further scan because the gestation of the scheduled scan was too early to measure NT (p < 0.0001, Chi-squared test). In contrast, with advancing gestation the rate of unsuccessful NT measurement because the crown–rump length (CRL) was greater than 84 mm significantly increased (p < 0.0001, Chi-squared test). Of the women who had had an earlier ultrasound, 42 (1.6%) had a missed miscarriage and 9 (0.3%) were over gestation at the time of the NT scan. These data suggest that when only the last menstrual period is known the optimum time to schedule a nuchal translucency measurement is at 12 to 13 weeks' gestation. Copyright © 2002 John Wiley & Sons, Ltd.     

The success of elutriate tests in extended prediction of water quality after a dredging operation under freshwater and saline conditions

Dredging simulation by elutriate tests accurately predicted concentrations of Hg, Cu, Mn and Fe released to the water column from contaminated sediment to within 1 order of magnitude. Hg and Cu concentrations increased by up to 7-fold after dredging, but declined to background concentrations within 48 h. Maximum loadings of Hg and Cu coincided with Fe and total organic carbon (TOC) water column concentrations, suggesting Hg and Cu are adsorbed onto particulates of Fe oxides and organic material. Seasonal changes in redox potential and temperature did not significantly affect metal release from sediments. Saline water did not cause significant increases in contaminant release from sediments to the water column over that observed for freshwater. Water quality standards of 1 µg l^–1 Hg and 28 µg l^–1 Cu as annual averages were not breached by dredging operations. Long-term effects of dredging on Hg and Cu availability, due to deposition of contaminated material as surficial sediments, is, however, of concern.     

BENTHIC MACROINVERTEBRATE COMMUNITY STRUCTURE IN A GREAT PLAINS STREAM RECEIVING FEEDLOT RUNOFF1

ABSTRACT The effect of feedlot runoff on the environmental quality of the Cottonwood River in east central Kansas was evaluated by analysis of community structure of benthic macroinvertebrates using the species diversity index, (d). The benthic fauna along the study reach was dominated by mayflies, caddisflies, midges, riffle beetles, and the pelecypod, Sphaerium. Sixty-five taxa were identified during the study; the benthic fauna was most abundant during the 1968–69 segment of the study. However, the mean 3 per station indicated the river was subject to moderate environmental stress, and 3's of those stations immediately downstream from feedlots were significantly lower than the 3 at the control station. There was a significant increase in d's during the 1970–71 segment of the study, following the closing of two feedlots. The results indicate periodic feedlot runoff had a continuing adverse affect on the environmental quality of the river, but recovery was rapid as the organic load on the river was reduced.