Replacing monocultures with mixed-species stands: Ecosystem service implications of two production forest alternatives in Sweden

Whereas there is evidence that mixed-species approaches to production forestry in general can provide positive outcomes relative to monocultures, it is less clear to what extent multiple benefits can be derived from specific mixed-species alternatives. To provide such insights requires evaluations of an encompassing suite of ecosystem services, biodiversity, and forest management considerations provided by specific mixtures and monocultures within a region. Here, we conduct such an assessment in Sweden by contrasting even-aged Norway spruce (Picea abies)-dominated stands, with mixed-species stands of spruce and birch (Betula pendula or B. pubescens), or spruce and Scots pine (Pinus sylvestris). By synthesizing the available evidence, we identify positive outcomes from mixtures including increased biodiversity, water quality, esthetic and recreational values, as well as reduced stand vulnerability to pest and pathogen damage. However, some uncertainties and risks were projected to increase, highlighting the importance of conducting comprehensive interdisciplinary evaluations when assessing the pros and cons of mixtures.     

Evaluating common drivers for color,iron and organic carbon in Swedish watercourses

The recent browning (increase in color) of surface waters across much of the northern hemisphere has important implications for light climate, ecosystem functioning, and drinking water treatability. Using log-linear regressions and long-term (6–21 years) data from 112 Swedish watercourses, we identified temporal and spatial patterns in browning-related parameters [iron, absorbance, and total organic carbon (TOC)]. Flow variability and lakes in the catchment were major influences on all parameters. Co-variation between seasonal, discharge-related, and trend effects on iron, TOC, and absorbance were dependent on pH, landscape position, catchment size, latitude, and dominant land cover. Large agriculture-dominated catchments had significantly larger trends in iron, TOC, and water color than small forest catchments. Our results suggest that while similarities exist, no single mechanism can explain the observed browning but show that multiple mechanisms related to land cover, climate, and acidification history are responsible for the ongoing browning of surface waters.     

Simulated Impacts of Climate Change on Current Farming Locations of Striped Catfish (Pangasianodon hypophthalmus; Sauvage) in the Mekong Delta,Vietnam

In Vietnam, culturing striped catfish makes an important contribution to the Mekong Delta’s economy. Water level rise during rainy season and salt intrusion during dry season affect the water exchange and quality for this culture. Sea level rise as a consequence of climate change will worsen these influences. In this study, water level rise and salt water intrusion for three sea level rise (SLR) scenarios (i.e., +30, +50, and +75 cm) were simulated. The results showed that at SLR +50, the 3-m-flood level would spread downstream and threaten farms located in AnGiang, DongThap and CanTho provinces. Rising salinity levels for SLR +75 would reduce the window appropriate for the culture in SocTrang and BenTre provinces, and in TienGiang’s coastal districts. Next to increasing dikes to reduce the impacts, the most tenable and least disruptive option to the farming community would be to shift to a salinity tolerant strain of catfish.     

Evidence-Based Knowledge Versus Negotiated Indicators for Assessment of Ecological Sustainability: The Swedish Forest Stewardship Council Standard as a Case Study

Assessing ecological sustainability involves monitoring of indicators and comparison of their states with performance targets that are deemed sustainable. First, a normative model was developed centered on evidence-based knowledge about (a) forest composition, structure, and function at multiple scales, and (b) performance targets derived by quantifying the habitat amount in naturally dynamic forests, and as required for presence of populations of specialized focal species. Second, we compared the Forest Stewardship Council (FSC) certification standards’ ecological indicators from 1998 and 2010 in Sweden to the normative model using a Specific, Measurable, Accurate, Realistic, and Timebound (SMART) indicator approach. Indicator variables and targets for riparian and aquatic ecosystems were clearly under-represented compared to terrestrial ones. FSC’s ecological indicators expanded over time from composition and structure towards function, and from finer to coarser spatial scales. However, SMART indicators were few. Moreover, they poorly reflected quantitative evidence-based knowledge, a consequence of the fact that forest certification mirrors the outcome of a complex social negotiation process.     

Evaluation of Multi-level Social Learning for Sustainable Landscapes: Perspective of a Development Initiative in Bergslagen, Sweden

To implement policies about sustainable landscapes and rural development necessitates social learning about states and trends of sustainability indicators, norms that define sustainability, and adaptive multi-level governance. We evaluate the extent to which social learning at multiple governance levels for sustainable landscapes occur in 18 local development initiatives in the network of Sustainable Bergslagen in Sweden. We mapped activities over time, and interviewed key actors in the network about social learning. While activities resulted in exchange of experiences and some local solutions, a major challenge was to secure systematic social learning and make new knowledge explicit at multiple levels. None of the development initiatives used a systematic approach to secure social learning, and sustainability assessments were not made systematically. We discuss how social learning can be improved, and how a learning network of development initiatives could be realized.     

Applications of isotope differentiation for metabolic studies with di‐(2‐ethylhexyl) phthalate

Abstract

The pervasiveness of the plasticizer di‐(2‐ethylhexyl) phthalate (DEHP) in the environment and especially in the laboratory results in a background that may cause severe interference with analytical studies. Animal‐to‐animal variability in the distribution of DEHP metabolites in excreta normally makes it necessary to use large groups of animals when different treatments are compared. Finally, radioactive tracers are usually considered undesirable for metabolic studies involving human subjects. All of these problems can be overcome through the use of muliple isotopic labels, especially ¹²C/¹³C/¹⁴C. Examples are given involving rats and monkeys, and applicability to humans is discussed. The principles involved are not limited to any particular class of test compounds. In rats, the competing pathways for metabolism of phthalate esters produce a different distribution of metabolites from a small intravenous dose of DEHP than from a large oral dose.     

Factorial validity of the Maslach burnout inventory—Dutch version (MBI‐NL) among dentists

Burnout is considered to be a long‐term reaction to occupational stress. It is characterized by emotional exhaustion, depersonalization, and diminished personal accomplishment. The most widely used instrument to measure burnout is the Maslach Burnout Inventory (MBI), developed by Maslach and Jackson (1986). From this instrument, Schaufeli and van Dierendonck (1995a) developed a somewhat modified Dutch version: the MBI‐NL. Burnout among dentists has hardly been studied. Since the professions that the MBI‐NL was developed upon are quite different from dentistry, the aim of this study was to test the three‐factor structure of the MBI‐NL against alternative structures among dentists. Both principal components analysis (PCA) and confirmatory factor analysis (CFA) were examined in a representative sample of 709 Dutch general dental practitioners (75 per cent response rate). The three‐factor structure shows the best fit to the underlying data, while other psychometric qualities are very satisfactory. It is concluded that the three‐factor structure of the MBI‐NL is superior to alternative structures, and that the MBI‐NL is a highly suitable instrument to measure burnout among dentists. Copyright © 1999 John Wiley & Sons, Ltd.     

Revisiting a statistical shortcoming when fitting the Langmuir model to sorption data

The Langmuir model is commonly used for describing the sorption behavior of reactive solutes to surfaces and is often fit to sorption data using nonlinear least squares regression. An important assumption of least squares regression is that the predictor variable is error free. In the case of sorption data, this assumption is not valid, and therefore the potential for parameter bias exists. Although alternative regression methods exist that either explicitly account for error in the predictor variable (Model II regression) or minimize the error in the predictor variable, these methods are not commonly used. Therefore, this paper more fully explores the differences in fitted parameters and model fits between these different data fitting methods by fitting P sorption data collected on 26 different soil samples using three different regression methods. For a majority of soils tested in this study, the differences in model fits between the three regression methods were not statistically significant. Statistical differences were observed in over a third of the soils, however, suggesting that errors in the predictor variable may be large enough to produce biased parameter estimates. These results suggest that multiple regression methods should be used when fitting the Langmuir model to sorption data to better assess the potential impact of error on model fits.     

Impact of growth conditions on transport behavior of E. coli

The aim of this investigation is to determine the effect that growth solution has on the cell surface properties and transport behavior of eleven Escherichia coli isolates through saturated porous media. The two growth solutions used were a standard laboratory growth medium (LB) and a dairy manure extract solution. In general, cells grown in manure extract were more hydrophobic, had a more negative zeta potential, had lower amounts of surface macromolecules, and had lower attachment efficiencies than isolates grown in LB. An inverse relationship between the natural log of zeta potential and the attachment efficiency of the isolates for the cells grown in LB media was the only statistically significant correlation observed between transport behavior and cell characteristics of the isolates. This study shows the need to consider growth conditions when studying bacteria to better mimic the environmental stresses that bacteria undergo in the natural environment. This approach could lead to a better understanding of the behavior of manure-derived bacteria in aquatic and terrestrial environments.