Interspecific observational memory in a non-caching Parus species,the great tit Parus major

Scatter-hoarding passerine birds have become a model system for research on spatial memory capacity. This research has focussed on two families, the Corvidae (crows, jays, nutcrackers, etc.) and the Paridae (titmice and chickadees). Corvids are considered to have highly developed cognitive skills that sometimes have been compared with the great apes. Even though pilfering, or stealing of caches made by others, is common among scatter-hoarding birds, the ability to memorize positions of caches made by others has only been demonstrated in some species of corvids. In parids, the ability to memorize positions of caches made by others has not been demonstrated. In a laboratory experiment, we allowed caged great tits to observe caching marsh tits and found that they remembered caching locations both 1 and 24 h after observation. This is the first time observational spatial learning of this type explicitly has been demonstrated in a parid. This ability is surprising since the great tit is not itself a food hoarder, meaning that it may not have the special memory adaptations in the brain that specialized food hoarders possess. Also, the memorization process in an observing pilferer may differ from the memorization that hoarders make of own caches. For example, the typical close inspection of the cache that hoarding parids do after caching will usually not be possible from a distance. Also, the visual perspective of the observing scrounger may be different from that of the hoarder, meaning that some understanding of allocentric space may be required.     

Comparison of different collection systems for sorted household waste in Sweden

Composition and quantity per person of municipal solid waste (MSW) have been analyzed in six municipalities in southern Sweden with similar socio-economic conditions but with different collection systems. Samples of residual waste have been sorted, classified and weighed in 21 categories during 26 analyses that took place from 1998-2004. Collection data of the total waste flow, including source sorted recycling materials, in the same area have been compiled and compared. Multivariate data analyses have been applied. Weight-based billing reduced delivered amounts of residual household waste by 50%, but it is unknown to what extent improper material paths had developed. With curbside collection more metal, plastic and paper packaging was separated and left to recycling. When separate collection of biodegradables was included in the curbside system, the overall sorting of dry recyclables increased. The large uncertainty associated with waste composition analyses makes it difficult to draw strong conclusions regarding the effects on specific recyclables or the changes in the composition of the residual waste.     

A boreal invasion in response to climate change? Range shifts and community effects in the borderland between forest and tundra

It has been hypothesized that climate warming will allow southern species to advance north and invade northern ecosystems. We review the changes in the Swedish mammal and bird community in boreal forest and alpine tundra since the nineteenth century, as well as suggested drivers of change. Observed changes include (1) range expansion and increased abundance in southern birds, ungulates, and carnivores; (2) range contraction and decline in northern birds and carnivores; and (3) abundance decline or periodically disrupted dynamics in cyclic populations of small and medium-sized mammals and birds. The first warm spell, 1930–1960, stands out as a period of substantial faunal change. However, in addition to climate warming, suggested drivers of change include land use and other anthropogenic factors. We hypothesize all these drivers interacted, primarily favoring southern generalists. Future research should aim to distinguish between effects of climate and land-use change in boreal and tundra ecosystems.     

Ethical Issues in Mitigation of Climate Change: The Option of Reduced Meat Production and Consumption

In this paper I discuss ethical issues related to mitigation of climate change. In particular, I focus on mitigation of climate change to the extent this change is caused by livestock production. I support the view—on which many different ethical approaches converge—that the present generation has a moral obligation to mitigate climate change for the benefit of future generations and that developed countries should take the lead in the process. Moreover, I argue that since livestock production is an important contributing factor to climate change, we should undertake mitigation measures also in this sector and not only in, for example, the transport and energy sectors. However, technological solutions do not seem sufficient in the livestock sector, leaving us with the option of reduced meat production and consumption. In order to reach significant results in mitigation of climate change, political steering seems necessary. With this in mind, I argue in favor of a tax on meat consumption.     

A temporal trend study (1972-2008) of perfluorooctanesulfonate, perfluorohexanesulfonate, and perfluorooctanoate in pooled human milk samples from Stockholm, Sweden

The widespread presence of perfluorooctanesulfonate (PFOS), perfluorooctanoate (PFOA), and perfluorohexanesulfonate (PFHxS) in human general populations and their slow elimination profiles have led to renewed interest in understanding the potential human neonatal exposures of perfluoroalkyls (PFAs) from consumption of human milk. The objective of this study was to evaluate the concentrations of PFOS, PFHxS, and PFOA in pooled human milk samples obtained in Sweden between 1972 and 2008 (a period representing the most significant period of PFA production) and to see whether the time trend of these analytes parallels that indicated in human serum. Chemical analysis of PFOS, PFHxS, and PFOA was performed on pooled Swedish human milk samples from 1972 to 2008 after methodological refinements. The 20 samples which formed the 2007 pool were also analyzed individually to evaluate sample variations. Analyses were performed by HPLC-MS/MS. Due to the complexities of the human milk matrix and the requirement to accurately quantitate low pg/mL concentrations, meticulous attention must be paid to background contamination if accurate results are to be obtained. PFOS was the predominant analyte present in the pools and all three analytes showed statistically significant increasing trends from 1972 to 2000, with concentrations reaching a plateau in the 1990s. PFOA and PFOS showed statistically significant decreasing trends during 2001-2008. At the end of the study, in 2008, the measured concentrations of PFOS, PFHxS, and PFOA in pooled human milk were 75 pg/mL, 14 pg/mL, and 74 pg/mL, respectively. The temporal concentration trends of PFOS, PFHxS, and PFOA observed in human milk are parallel to those reported in the general population serum concentrations.     

Two-dimensional gap analysis: a tool for efficient conservation planning and biodiversity policy implementation

The maintenance of biodiversity by securing representative and well-connected habitat networks in managed landscapes requires a wise combination of protection, management, and restoration of habitats at several scales. We suggest that the integration of natural and social sciences in the form of "Two-dimensional gap analysis" is an efficient tool for the implementation of biodiversity policies. The tool links biologically relevant "horizontal" ecological issues with "vertical" issues related to institutions and other societal issues. Using forest biodiversity as an example, we illustrate how one can combine ecological and institutional aspects of biodiversity conservation, thus facilitating environmentally sustainable regional development. In particular, we use regional gap analysis for identification of focal forest types, habitat modelling for ascertaining the functional connectivity of "green infrastructures", as tools for the horizontal gap analysis. For the vertical dimension we suggest how the social sciences can be used for assessing the success in the implementation of biodiversity policies in real landscapes by identifying institutional obstacles while implementing policies. We argue that this interdisciplinary approach could be applied in a whole range of other environments including other terrestrial biota and aquatic ecosystems where functional habitat connectivity, nonlinear response to habitat loss and a multitude of economic and social interests co-occur in the same landscape.     

Bone mineral density in male Baltic grey seal (Halichoerus grypus)

Bone mineral density (mg cm(-3)) was studied in male Baltic grey seals (4-23 years of age) by noninvasive computed tomography (pQCT). The material was grouped according to year of collection. Group A: 1850-1955, a period before the main introduction of organochlorines (OCs); Group B: 1965-1985, a period with very high OC contamination; and Group C: 1986-1997, a period with decreasing concentrations of OCs. The reproducibility of the measurements was good with a Coefficient of Variation (CV) ranging from 0.1% to 2.1%. Trabecular bone mineral density of the radius was significantly higher in specimens collected 1986-1997 than in those collected 1965-1985 (p < 0.05). Cortical bone mineral density of the mandible was significantly lower in specimens collected 1986-1997 compared with those collected 1850-1955 (p < 0.05). These results indicate different responses over time in trabecular and cortical bone. During the period of very high OC contamination (1965-1985), trabecular bone density was lowest, whereas cortical bone density was lowest in specimens collected 1985-1997, representing a period of fairly low OC contamination. The mechanisms behind these effects are not known. However, it can be assumed that OCs are involved. Information about residue levels of OCs in the studied individuals is lacking and, therefore, it was not possible to evaluate the impact of OCs in this respect.     

The potential of vehicle and road infrastructure interventions in fatal bicyclist accidents on Swedish roads—What can in-depth studies tell us?

Abstract

Objective: The objective of this article is to describe the characteristics of fatal crashes with bicyclists on Swedish roads in rural and urban areas and to investigate the potential of bicycle helmets and different vehicle and road infrastructure interventions to prevent them. The study has a comprehensive approach to provide road authorities and vehicle manufacturers with recommendations for future priorities.

Methods: The Swedish Transport Administration’s (STA) in-depth database of fatal crashes was used for case-by-case analysis of fatal cycling accidents (2006–2016) on rural (n?=?82) and urban (n?=?102) roads. The database consists of information from the police, medical journals, autopsy reports, accident analyses performed by STA, and witness statements. The potential of helmet use and various vehicle and road infrastructure safety interventions was determined retrospectively for each case by analyzing the chain of events leading to the fatality. The potential of vehicle safety countermeasures was analyzed based on prognoses on their implementation rates in the Swedish vehicle fleet.

Results: The most common accident scenario on rural roads was that the bicyclist was struck while cycling along the side of the road. On urban roads, the majority of accidents occurred in intersections. Most accidents involved a passenger car, but heavy trucks were also common, especially in urban areas. Most accidents occurred in daylight conditions (73%). Almost half (46%) of nonhelmeted bicyclists would have survived with a helmet. It was assessed that nearly 60% of the fatal accidents could be addressed by advanced vehicle safety technologies, especially autonomous emergency braking with the ability to detect bicyclists. With regard to interventions in the road infrastructure, separated paths for bicyclists and bicycle crossings with speed calming measures were found to have the greatest safety potential. Results indicated that 91% of fatally injured bicyclists could potentially be saved with known techniques. However, it will take a long time for such technologies to be widespread.

Conclusions: The majority of fatally injured bicyclists studied could potentially be saved with known techniques. A speedy implementation of important vehicle safety systems is recommended. A fast introduction of effective interventions in the road infrastructure is also necessary, preferably with a plan for prioritization.     

Interaction webs in arctic ecosystems: Determinants of arctic change?

How species interact modulate their dynamics, their response to environmental change, and ultimately the functioning and stability of entire communities. Work conducted at Zackenberg, Northeast Greenland, has changed our view on how networks of arctic biotic interactions are structured, how they vary in time, and how they are changing with current environmental change: firstly, the high arctic interaction webs are much more complex than previously envisaged, and with a structure mainly dictated by its arthropod component. Secondly, the dynamics of species within these webs reflect changes in environmental conditions. Thirdly, biotic interactions within a trophic level may affect other trophic levels, in some cases ultimately affecting land–atmosphere feedbacks. Finally, differential responses to environmental change may decouple interacting species. These insights form Zackenberg emphasize that the combination of long-term, ecosystem-based monitoring, and targeted research projects offers the most fruitful basis for understanding and predicting the future of arctic ecosystems.     

Limited microbial degradation of pyrene metabolites from the estuarine polychaete Nereis diversicolor

We compared microbial mineralization of [4,5,9,10-14C]pyrene and its eukaryotic [4,5,9,10-14C]pyrene metabolites in estuarine sediments. Metabolites were obtained by exposing the estuarine deposit-feeding polychaete Nereis diversicolor to sediment-associated 14C-pyrene, followed by homogenization of the worms and extraction of the pyrene-metabolites. In sediment from a pristine Danish Fjord only 2.6% of the added metabolite-label and 1.7% of the pyrene-label were mineralized to 14CO2 during 175 days incubation. Pre-exposure of the pristine sediment to unlabelled pyrene for 60 days increased the mineralization potential for 14C-pyrene substantially, as 81.2% was mineralized to 14CO2 during 95 days incubation, whereas 14C-pyrene metabolite label was unaffected by pre-exposure to pyrene. In comparison, naturally aged bunker-oil contaminated sediment did not show elevated potentials for mineralization of neither 14C-pyrene nor 14C-metabolites. Six bacterial strains of known pyrene degraders were tested for growth on crystalline 1-hydroxypyrene. 1-Hydroxypyrene is the only intermediate eucaryotic metabolite of pyrene. The results indicate that 1-hydroxypyrene was not utilized as a sole source of carbon and energy by any of them. In addition, respiration was depressed in all six strains when exposed to crystalline 1-Hydroxypyrene, demonstrating an acute toxic effect of 1-hydroxypyrene. The results presented here suggest that microbial degradation of pyrene is not enhanced by release of aqueous and polar metabolites by marine invertebrates.