1. Although anthropogenic edges are an important consequence of timber harvesting, edges due to natural disturbances or landscape heterogeneity are also common. Forest edges have been well studied in ...temperate and tropical forests, but less so in less productive, disturbance-adapted boreal forests. 2. We synthesized data on forest vegetation at edges of boreal forests and compared edge influence among edge types (fire, cut, lake/wetland; old vs. young), forest types (broadleaf vs. coniferous) and geographic regions. Our objectives were to quantify vegetation responses at edges of all types and to compare the strength and extent of edge influence among different types of edges and forests. 3. Research was conducted using the same general sampling design in Alberta, Ontario and Quebec in Canada, and in Sweden and Finland. We conducted a meta-analysis for a variety of response variables including forest structure, deadwood abundance, regeneration, understorey abundance and diversity, and non-vascular plant cover. We also determined the magnitude and distance of edge influence (DEI) using randomization tests. 4. Some edge responses (lower tree basal area, tree canopy and bryophyte cover; more logs; higher regeneration) were significant overall across studies. Edge influence on ground vegetation in boreal forests was generally weak, not very extensive (DEI usually < 20 m) and decreased with time. We found more extensive edge influence at natural edges, at younger edges and in broadleaf forests. The comparison among regions revealed weaker edge influence in Fennoscandian forests. 5. Synthesis. Edges created by forest harvesting do not appear to have as strong, extensive or persistent influence on vegetation in boreal as in tropical or temperate forested ecosystems. We attribute this apparent resistance to shorter canopy heights, inherent heterogeneity in boreal forests and their adaptation to frequent natural disturbance. Nevertheless, notable differences between forest structure responses to natural (fire) and anthropogenic (cut) edges raise concerns about biodiversity implications of extensive creation of anthropogenic edges. By highlighting universal responses to edge influence in boreal forests that are significant irrespective of edge or forest type, and those which vary by edge type, we provide a context for the conservation of boreal forests.
To integrate biochar as a practical and successful remedial amendment at northern landfarms, components of its formulation and application must be optimized for site-specific environmental ...conditions. Different biochar amendments were applied to petroleum hydrocarbon (PHC)-contaminated soil at two northern field sites (Iqaluit and Whitehorse) and in a laboratory study at -5°C to determine the effects of application method (injection or incorporation) and biochar type (wood, fishmeal, bonemeal, and/or compost) on PHC degradation and associated soil properties. Incorporation decreased F2 (equivalent C-C) and F3 (equivalent C-C) PHC concentrations in soil after 31 d, whereas injection did not decrease PHC concentrations until Day 334. Bonemeal-derived biochar selectively stimulated F3-PHC degradation in frozen soil over 90 d under controlled laboratory conditions. In the field, there was little difference in PHC degradation between biochar types and the fertilizer control. Incorporation also increased NO availability, and in field trials, all biochars increased NO availability relative to the fertilizer control, whereas the effects of biochars on NH and PO were variable. Aromatic functional gene abundance was enhanced when treatments were incorporated, compared with when injected. In field trials, 6% Zakus wood plus fertilizer inhibited aliphatic and aromatic gene abundance. Liquid water content increased in incorporated treatments, specifically those amended with fishmeal biochar. Incorporation was the most successful application method for these northern soils, and although biochar amendments are not clearly effective in reducing PHC concentrations, there is evidence to suggest it can beneficially influence soil properties and PHC degradation under specific environmental conditions.
Sulphur cinquefoil (Potentilla recta L.) is an invasive plant of concern within grasslands in western North America. To better understand the role of native plant communities and soil seedbank in P. ...recta invasion within grasslands, we conducted two greenhouse studies to examine (1) P. recta growth response when grown with and without fertilizer in established native plant communities of varying functional groups (grasses, forbs, or grasses and forbs), and (2) the prevalence of P. recta and other species in the soil seedbank at varying soil depths (0 to 5 cm, 5 to 10 cm, 10 to 15 cm) of grasslands invaded by P. recta in southeastern British Columbia, Canada. The growth response of P. recta did not differ between the native plant communities. However, P. recta above- and belowground biomass declined as native plant aboveground biomass increased, suggesting a productive plant community may be important to suppress P. recta. Fertilizer did not affect the growth response of P. recta or native plants, suggesting nutrients may not have been a dominant limiting factor under greenhouse conditions. Nine species were identified in the soil seedbank. Seven were nonnative, which included P. recta, and native species represented less than 2% of the seedbank. Of the average number of emerged nonnative seedlings, more than 20% were P. recta. The number of emerged P. recta seedlings was 69% lower at 10- to 15-cm compared with 0- to 5-cm soil depth, although the successful germination of P. recta at greater soil depths suggests viable P. recta seeds are persisting in the seedbank. Active revegetation may be an important strategy to mitigate P. recta reinvasion or secondary invasion by other invasive species from the soil seedbank.
Available soil N is a key factor limiting plant productivity in most low arctic terrestrial ecosystems. Atmospheric N2-fixation by cyanobacteria is often the primary source of newly fixed N in these ...nutrient-poor environments. We examined temporal and spatial variation in N2-fixation by the principal cyanobacterial associations (biological soil crusts, Sphagnum spp. associations, and Stereocaulon paschale) in a wide range of ecosystems within a Canadian low arctic tundra landscape, and estimated N input via N2-fixation over the growing season using a microclimatically driven model. Moisture and temperature were the main environmental factors influencing N2-fixation. In general, N2-fixation rates were largest at the height of the growing season, although each N2-fixing association had distinct seasonal patterns due to ecosystem differences in microclimatic conditions. Ecosystem types differed strongly in N2-fixation rates with the highest N input (10.89 kg ha−1 yr−1) occurring in low-lying Wet Sedge Meadow and the lowest N input (0.73 kg ha−1 yr−1) in Xerophytic Herb Tundra on upper esker slopes. Total growing season (3 June–13 September) N2-fixation input from measured components across a carefully mapped landscape study area (26.7 km2) was estimated at 0.68 kg ha−1 yr−1, which is approximately twice the estimated average N input via wet deposition. Although biological N2-fixation input rates were small compared to internal soil N cycling rates, our data suggest that cyanobacterial associations may play an important role in determining patterns of plant productivity across low arctic tundra landscapes.
Edge effects resulting from adjacent land uses are poorly understood in agroecosystems yet understanding above and belowground edge effects is crucial for maintaining ecosystem function. The aim of ...our study was to examine impacts of land management on aboveground and belowground edge effects, measured by changes in plant community, soil properties, and soil microbial communities across agroecosystem edges. We measured plant composition and biomass, soil properties (total carbon, total nitrogen, pH, nitrate, and ammonium), and soil fungal and bacterial community composition across perennial grassland-annual cropland edges. Edge effects due to land management were detected both aboveground and belowground. The plant community at the edge was distinct from the adjacent land uses, where annual, non-native, plant species were abundant. Soil total nitrogen and carbon significantly decreased across the edge (P < 0.001), with the highest values in the perennial grasslands. Both bacterial and fungal communities were different across the edge with clear changes in fungal communities driven directly and indirectly by land management. A higher abundance of pathogens in the more heavily managed land uses (i.e. crop and edge) was detected. Changes in plant community composition, along with soil carbon and nitrogen also influenced the soil fungal community across these agroecosystems edges. Characterizing edge effects in agroecosystem, especially those associated with soil microbial communities, is an important first step in ensuring soil health and resilience in these managed landscapes.
There is an abundance of research on the health consequences of sexual assault during university, but less attention has been paid to how sexual assault also shapes women’s everyday lives. To develop ...an understanding of the everyday aftermath of sexual assault, we used narrative inquiry to analyze how women textually represent everyday living after sexual assault during university within four memoirs. Memoirists discussed their lives as significantly changed and worked to repair their lives after sexual assault by engaging in a range of everyday activities. Although no single behavioral response was described, some memoirists were perceived as deviant if they engaged in behaviors that contradicted prevailing cultural myths and expectations about how one should behave after sexual assault. We need to create room for women to engage in personal, idiosyncratic responses if we are to challenge restrictive standards for doing in the aftermath of sexual assault during university.
In the Yukon Territory, transmission rights-of-way (ROWs) are managed using brushing and mowing techniques alone. When cut, target species such as Michx. and spp. grow rapidly shortening maintenance ...cycles. Long-term vegetation control may be improved by integrating herbicide application. However, prior to implementation, the dissipation and toxicity of herbicides in northern latitudes needed to be assessed. The dissipation of Garlon XRT (triclopyr) and Arsenal Powerline (imazapyr) in soils was assessed at five ROW locations representative of the main ecoregion types where ROWs occur within the Yukon Territory. Soils from four sites were collected at 1, 30, and 365 d after treatment to determine persistence of herbicides for each of three application methods (backpack spraying, cut stump, and point injection). Increased sampling intervals were added to better determine the dissipation rate of each herbicide in Yukon Territory soils. Soil dissipation data were linked to a series of standardized toxicity tests, including three soil invertebrates (, , and ). Additionally, the dissipation of both herbicides from the target species L. was assessed at one site. Herbicide residues persisted in soils for longer than 365 d after treatment and longer than 30 d after treatment in . However, concentrations were below the concentration that would affect 25% of the invertebrate species tested. Weight of evidence and toxic exposure ratios were used to characterize the risks associated with herbicide application in northern latitudes and provided both qualitative and quantitative means to communicate the results to the public.
This paper presents a novel single-port multi-pole resonant sensor array fabricated on a novel Frame-Flex flexible substrate for a wearable epidermal ethanol sensor system, in which individual ...sensors carrying different functional polymers are brought together to share the same electrical input and output, and their resonance behavior along with inter-resonator coupling are captured through the single reflected array response curve ( S 11). The coupling-matrix readout extraction (CMRE) technique is then further proposed to determine, from the S 11 response, the changes in the diagonal-coupling coefficient, ΔM ii , which are used to identify different chemical analytes as the coupling signature. Two sensor arrays implementing different functional polymer sets-one with siloxane-based polymers and the other with crystalline-based polymers-are fabricated and tested under two selected mechanical loading conditions. The CMRE technique is then employed to obtain the coupling signatures of ethanol, methanol, acetone, and benzene on the arrays. It is successfully shown that the array response analyzed through the CMRE technique can clearly distinguish the presence of ethanol from other chemical interferents. For complicated mixtures of ethanol and other unwanted analytes, the distinctive coupling signatures obtained by CMRE can be used as a reliable data source fed to post-readout multi-variant analysis for pattern recognition.
Previous work has shown American obstetrics and gynecology (OB/GYN) residents are lacking in menopause training. Our objective was to assess the effectiveness of a 2-year menopause medicine ...curriculum in improving OB/GYN residents' knowledge and self-assessed competency in menopause topics.
We developed a menopause medicine-teaching curriculum for OB/GYN residents at our academic hospital-based residency program. The 2-year curriculum was composed of year 1: four 1-hour lectures and one 2-hour lab with cases presentations, and year 2: three 1-hour lectures and one 2-hour lab. Core topics included menopause physiology, hormone therapy, breast health, bone health, cardiovascular disease, and autoimmune disease. Pre- and posttests assessed resident knowledge and comfort in core topics, and a pre- and postcurriculum survey assessed utility and learning satisfaction.
From July 2011 to June 2013, 34 OB/GYN residents completed the menopause curriculum annually with an average attendance at each module of 23 residents. Pre-/posttest scores improved from a mean pretest score of 57.3% to a mean posttest score of 78.7% (P < 0.05). Before the curriculum, most residents did not feel comfortable managing menopause patients with 75.8% reporting feeling "barely comfortable" and 8.4% feeling "not at all comfortable." After the 2-year curriculum, 85.7% reported feeling "comfortable/very comfortable" taking care of menopause patients. The majority of residents (95.2%) reported the menopause curriculum was "extremely useful."
A 2-year menopause medicine curriculum for OB/GYN residents utilizing lectures and a lab with case studies is an effective modality to improve resident knowledge required to manage menopause patients.
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