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.     

The legitimacy of leadership in international climate change negotiations

Leadeship is an essential ingredient in reaching international agreements and overcoming the collective action problems associated with responding to climate change. In this study, we aim at answering two questions that are crucial for understanding the legitimacy of leadership in international climate change negotiations. Based on the responses of the three consecutive surveys distributed at COPs 14-16, we seek first to chart which actors are actually recognized as leaders by climate change negotiation participants. Second, we aim to explain what motivates COP participants to support different actors as leaders. Both these questions are indeed crucial for understanding the role, importance, and legitimacy of leadership in the international climate change regime. Our results show that the leadership landscape in this issue area is fragmented, with no one clear-cut leader, and strongly suggest that it is imperative for any actor seeking recognition as climate change leader to be perceived as being devoted to promoting the common good.     

Environmental monitoring and research in the Abisko area-an overview

This article gives an overview of the studies on the environment surrounding the Abisko Scientific Research Station in Swedish Lapland. The long-term monitoring of the Station on processes related to the climate, and to the physical, biotic, and chemical environmental conditions is particularly addressed. Some variables are recorded since more than 100 years. The obtained data in combination with results from short-term studies and manipulation experiments are important to understand past and future conditions of the ecosystems. This has practical applications for the planning of tourism, transports, reindeer herding, and for societal purposes.     

Experimental methods of determining the activity depth distribution of implanted 210Pb in glass

Glass is often used in radon surveys to estimate retrospective radon concentrations, as radon progenies are embedded in the upper surface layer. Experimental methods based on etching to determine the depth distribution of recoil-implanted 210Po in glass from radon decay in air is presented. By carefully controlling chemical concentrations and exposure time during which the glass is etched, stepwise removal of the surface material was possible. Two different etching agents, diluted HF/HNO3 and NaOH were utilised, with very similar results. Experimental recoil depths of 210Po agree with theoretical calculations from the literature. The maximum implantation depth obtained using this procedure was 100 +/- 20nm.     

Reproductive synchrony in the fieldfare (Turdus pilaris) in relation to spring arrival,nest predation and nestling starvation

Summary In SW Sweden, solitary fieldfares (Turdus pilaris) were synchronized to the same degree as those living in colonies. In N Sweden, I investigated the degree of synchronization among colonies of varying size because solitary breeding occurred only occasionally. The degree of synchronization was not related to colony size. Synchronization was strongest in years when breeding started late and weakest in years when breeding commenced early. In N Sweden, the nest predation risk increased slightly as the season progressed. In SW Sweden, nestling mortality due to starvation was highest in early breeders, but their fledgling production exceeded that of late breeders. Increased nest predation penalized late layers.     

Road dust emissions from paved roads measured using different mobile systems

Very few real-world measurements of road dust suspension have been performed to date. This study compares two different techniques (referred to as Sniffer and Emma) to measure road dust emissions. The main differences between the systems are the construction of the inlet, different instruments for recording particulate matter (PM) levels, and different loads on the wheel axes (the weight of Sniffer was much higher than that of Emma). Both systems showed substantial small-scale variations of emission levels along the road, likely depending on-road surface conditions. The variations observed correlated quite well, and the discrepancies are likely a result of variations in dust load on the road surface perpendicular to the driving direction that cause variations in the measurements depending on slightly different paths driven by the two vehicles. Both systems showed a substantial influence on the emission levels depending on the type of tire used. The summer tire showed much lower suspension than the winter tires (one nonstudded and one studded). However, the relative importance of the nonstudded versus studded tire was rather different. For the ratio of studded/nonstudded, Emma shows higher values on all road sections compared with Sniffer. Both techniques showed increased emission levels with increasing vehicle speed. When the speed increased from 50 to 80 km hr(-1), the relative concentrations increased by 30-170% depending on the tire type and dust load. However, for road sections that were very dirty, Sniffer showed a much higher relative increase in the emission level with the nonstudded tire. Sniffer's absolute concentrations were mostly higher than Emma's. Possible reasons for the differences are discussed in the paper. Both systems can be used for studying relative road dust emissions and for designing air quality management strategies.     

Basic principles and ecological consequences of changing water regimes: riparian plant communities

Recent research has emphasized the importance of riparian ecosystems as centers of biodiversity and links between terrestrial and aquatic systems. Riparian ecosystems also belong among the environments that are most disturbed by humans and are in need of restoration to maintain biodiversity and ecological integrity. To facilitate the completion of this task, researchers have an important function to communicate their knowledge to policy-makers and managers. This article presents some fundamental qualities of riparian systems, articulated as three basic principles. The basic principles proposed are: (1) The flow regime determines the successional evolution of riparian plant communities and ecological processes. (2) The riparian corridor serves as a pathway for redistribution of organic and inorganic material that influences plant communities along rivers. (3) The riparian system is a transition zone between land and water ecosystems and is disproportionately plant species-rich when compared to surrounding ecosystems. Translating these principles into management directives requires more information about how much water a river needs and when and how, i.e., flow variables described by magnitude, frequency, timing, duration, and rate of change. It also requires information about how various groups of organisms are affected by habitat fragmentation, especially in terms of their dispersal. Finally, it requires information about how effects of hydrologic alterations vary between different types of riparian systems and with the location within the watershed.     

Chromosomal genes conferring tolerance to heavy metal (Ag) toxicity

Bacterial strains were isolated from sediment samples from the Thames River. Successive transfer growth of the various strains on nutrient agar containing increasing concentrations of AgNO₃ revealed that three of the bacterial isolates were found to be capable of tolerating high concentrations of AgNO₃ ranging from 20 to 80 mM on a solid medium and up to 10 mM AgNO₃ in liquid medium. Molecular characterization and identification based on 16S rDNA gene sequencing of three strains of bacteria that are tolerant to silver nitrate showed that the major tolerant strains include the superbug, Shewanella oneidensis, Pseudomonas sp. and Bacillus sp. Protein extraction and two-dimensional (2D) sodium dodecyl sulfate SDS-polyacrylamide gel electrophoresis (PAGE) of the protein extracts in bacteria exposed to very high concentrations of AgNO₃ revealed a general reduction in the number of expressed proteins, although two protein spots were conspicuously over expressed in the exposed bacteria compared to control. The N-terminal amino acid sequence analysis of the protein spots identified the major up-regulated proteins as the outer membrane protein To1C (45.2 kDa) and the structural protein of the flagellar filament, flagellin (28.34 kDa), encoded for by the to1C and fliC genes, respectively. The roles of these genes in a number of multi-drug resistant pathogen and potentials for biotechnological applications in toxic metal control for treatment of contaminated ecosystems and biomining were discussed.