Learning abatement costs: On the dynamics of the optimal regulation of experience goods

We study the introduction of new technologies when their costs are subject to idiosyncratic uncertainty and can only be fully learned through individual experience. We set up a dynamic model of clean experience goods that replace old polluting consumption options and show how optimal regulation evolves over time. In our base setting where social and private learning incentives coincide, the optimal tax on the polluting consumption is increasing over time. We show, however, that if social and private learning incentives diverge because the private discount rate exceeds the social discount rate, it may be optimal to temporarily increase the tax rate beyond net marginal external damages to induce more learning before reducing the tax rate to the steady state level. Alternatively, one could complement the tax with subsidies for first-time users which can be phased out over time. Similar results apply if consumers have biased expectations. We therefore give a rationale for introductory subsidies on new, clean technologies and non-monotonic tax paths from a perspective of consumer learning.     

Neighboring groups and habitat edges modulate range use in Phayre’s leaf monkeys (<Emphasis Type="Italic">Trachypithecus phayrei crepusculus</Emphasis>)

An animal’s use of space may be strongly influenced by habitat edges and neighboring conspecifics encountered in and around its home range. Habitat edges are known to affect species density and distribution, but their impact on home range use is largely unknown. Additionally, among large animals, interactions with neighbors become particularly important as increasing home range size leads to decreasing exclusivity of resource use, but the effect of neighbors on home range use remains poorly understood. Here, we examine the influence of neighbors and habitat edges on the ranging patterns of three groups of Phayre’s leaf monkeys (Trachypithecus phayrei crepusculus) in northeast Thailand over a period of more than 2 years. The study animals occupied dry evergreen forest, and adjacent patches of dry dipterocarp forest created a habitat edge and formed barriers between some groups. We found that the use of home range interiors was 50–90% higher than the border areas, indicating concentrated use of resources within the home range. The use of peripheral areas was influenced by social organization, the presence of neighboring groups, and forest edges. While one multimale group showed no particular habitat preference, two single-male groups preferred areas bordering dry dipterocarp habitat and avoided areas bordering neighboring groups, suggesting that the threat of neighbors mediated border presence. Additionally, groups may have been attracted to the forest edge, where conspecific competitors are absent and increased sunlight may increase resource abundance and/or quality. This study revealed that the use of border areas can be modulated by neighboring groups and habitat edges, thereby adding to our understanding of home range use among territorial species in heterogeneous habitats.     

Strategic male signalling effort in a desert-dwelling fish

Males often use elaborate courtship displays to attract females for mating. Much attention, in this regard, has been focused on trying to understand the causes and consequences of signal variation among males. Far less, by contrast, is known about within-individual variation in signal expression and, in particular, the extent to which males may be able to strategically adjust their signalling output to try to maximise their reproductive returns. Here, we experimentally investigated male courtship effort in a fish, the Australian desert goby, Chlamydogobius eremius. When offered a simultaneous choice between a large and a small female, male gobies spent significantly more time associating with, and courting, the former, probably because larger females are also more fecund. Male signalling patterns were also investigated under a sequential choice scenario, with females presented one at a time. When first offered a female, male courtship was not affected by female size. However, males adjusted their courtship effort towards a second female depending on the size of the female encountered previously. In particular, males that were first offered a large female significantly reduced their courtship effort when presented with a subsequent, smaller, female. Our findings suggest that males may be able to respond adaptively to differences in female quality, and strategically adjust their signalling effort accordingly.     

Pathogen-associated self-medication behavior in the honeybee Apis mellifera

Honeybees, Apis mellifera, have several prophylactic disease defense strategies, including the foraging of antibiotic, antifungal, and antiviral compounds of plant products. Hence, honey and pollen contain many compounds that prevent fungal and bacterial growth and inhibit viral replication. Since these compounds are also fed to the larvae by nurse bees, they play a central role for colony health inside the hive. Here, we show that honeybee nurse bees, infected with the microsporidian gut parasite Nosema ceranae, show different preferences for various types of honeys in a simultaneous choice test. Infected workers preferred honeys with a higher antibiotic activity that reduced the microsporidian infection after the consumption of the honey. Since nurse bees feed not only the larvae but also other colony members, this behavior might be a highly adaptive form of therapeutic medication at both the individual and the colony level.     

A novel participatory and remote-sensing-based approach to mapping annual land use change on forest frontiers in Laos,Myanmar, and Madagascar

Tropical forests are under pressure from both commercial and smallholder agriculture. Forest frontiers are seeing dynamic land use changes that frequently lead to land system regime shifts, posing challenges for the sustainability of entire local social-ecological systems. Monitoring highly dynamic land use change and detecting land system regime shifts is methodologically challenging due to trade-offs between spatial and temporal data resolution. We propose an innovative approach that combines analysis of very-high-resolution satellite imagery with participatory mapping based on workshops and field walks. Applying it in Laos, Myanmar, and Madagascar, we were able to collect annual land use information over several decades. Unlike conventional land use change mapping approaches, which assess only few points in time, our approach provides information at a temporal resolution that enables detection of gradual and abrupt land system regime shifts.     

A unified approach for including non-extractable residues (NER) of chemicals and pesticides in the assessment of persistence

All chemicals form non-extractable residues (NER) to various extents in environmental media like soil, sediment, plants and animals. NER can be quantified in environmental fate studies using isotope-labeled (such as ¹⁴C or ¹³C) tracer compounds. Previous NER definitions have led to a mismatch of legislation and state of knowledge in research: the residues are assumed to be either irreversibly bound degradation products or at least parts of these residues can be released. In the latter assumption, soils and sediments are a long-term source of slowly released residues. We here present a conceptual experimental and modeling approach to characterize non-extractable residues and provide guidance how they should be considered in the persistence assessment of chemicals and pesticides. Three types of NER can be experimentally discriminated: sequestered and entrapped residues (type I), containing either the parent substance or xenobiotic transformation products or both and having the potential to be released, which has indeed been observed. Type II NER are residues that are covalently bound to organic matter in soils or sediments or to biological tissue in organisms and that are considered being strongly bound with very low remobilization rates like that of humic matter degradation rates. Type III NER comprises biogenic NER (bioNER) after degradation of the xenobiotic chemical and anabolic formation of natural biomolecules like amino acids and phospholipids, and other biomass compounds. We developed the microbial turnover to biomass (MTB) model to predict the formation of bioNER based on the structural properties of chemicals. Further, we proposed an extraction sequence to obtain a matrix containing only NER. Finally, we summarized experimental methods to distinguish the three NER types. Type I NER and type II NER should be considered as potentially remobilizable residues in persistence assessment but the probability of type II release is much lower than that of type I NER, i.e., type II NER in soil are “operationally spoken” irreversibly bound and can be released only in minute amounts and at very slow rates, if at all. The potential of remobilization can be evaluated by chemical, physical and biological methods. BioNER are of no environmental concern and, therefore, can be assessed as such in persistence assessment. The general concept presented is to consider the total amount of NER minus potential bioNER as the amount of xenoNER, type I?+?II. If a clear differentiation of type I and type II is possible, for the calculation of half-life type I NER are considered as not degraded parent substance or transformation product(s). On the contrary, type II NER may generally be considered as (at least temporarily) removed. Providing proof for type II NER is the most critical issue in NER assessment and requires additional research. If no characterization and additional information on NER are available, it is recommended to assess the total amount as potentially remobilizable. We propose our unified approach of NER characterization and evaluation to be implemented into the persistence and environmental hazard assessment strategies for REACH chemicals and biocides, human and veterinary pharmaceuticals, and pesticides, irrespective of the different regulatory frameworks.     

Investigation of odors in the fragrance industry

Scents form the basis for the fragrance industry and various research activities have been developed in different scientific disciplines all being linked by a common interest in odors and odor perception. In this paper, four different topics have been selected for a short discussion. Following a short overview on the history of perfumery, the first topic (Natural scents) is providing some insight into the investigation of natural scents and how this work has strongly stimulated fragrance creation as well as the quest to find new odoriferous substances for the perfumer’s palette. The second subject (Fragrance chemistry) gives a historical overview over the chemistry of fragrances and briefly describes the rational behind the synthesis and composition of new scents. Body odors and their biochemical formation concern the third topic (Body odor biochemistry) which describes our current understanding of this scientifically interesting field and how knowledge may find use to improve future deodorant products. The fourth subject (Olfactory mechanisms) deals with the biochemistry in the human nose when odorants are activating olfactory receptors and enzymes appear to rapidly metabolize the inhaled odorous stimuli. This review does not attempt to be comprehensive, but it describes selected successes in the fragrance industry and the motivation behind conducting various types of research. Ultimately, the activities are aiming to bring new ingredients onto the market and improve the quality of scented products but also to advance our understanding of the power of communication through fragrance.     

The four faces of the environmental state: environmental governance regimes in 28 countries

The primary task for the environmental state is to address problems related to the market’s externalisation of environmental costs. It has four main resources at its disposal: regulation, redistribution, organisation, and knowledge generation. The way these four resources are deployed make up a state’s environmental governance arrangements. Using data on environmental regulation, taxes, public administrations, and knowledge production from 28 countries, and a hierarchical cluster analysis, four different types of environmental states are identified: established, emerging, partial, and weak. This is followed by some suggestions for further research on the environmental state in a comparative perspective.     

Vegetation phenology gradients along the west and east coasts of Greenland from 2001 to 2015

The objective of this paper is to characterize the spatiotemporal variations of vegetation phenology along latitudinal and altitudinal gradients in Greenland, and to examine local and regional climatic drivers. Time-series from the Moderate Resolution Imaging Spectroradiometer (MODIS) were analyzed to obtain various phenological metrics for the period 2001–2015. MODIS-derived land surface temperatures were corrected for the sampling biases caused by cloud cover. Results indicate significant differences between West and East Greenland, in terms of both observed phenology during the study period, as well as the climatic response. The date of the start of season (SOS) was significantly earlier (24 days), length of season longer (25 days), and time-integrated NDVI higher in West Greenland. The sea ice concentration during May was found to have a significant effect on the date of the SOS only in West Greenland, with the strongest linkage detected in mid-western parts of Greenland.