Are You Your Friends’ Friend? Poor Perception of Friendship Ties Limits the Ability to Promote Behavioral Change

Persuasion is at the core of norm creation, emergence of collective action, and solutions to ‘tragedy of the commons’ problems. In this paper, we show that the directionality of friendship ties affect the extent to which individuals can influence the behavior of each other. Moreover, we find that people are typically poor at perceiving the directionality of their friendship ties and that this can significantly limit their ability to engage in cooperative arrangements. This could lead to failures in establishing compatible norms, acting together, finding compromise solutions, and persuading others to act. We then suggest strategies to overcome this limitation by using two topological characteristics of the perceived friendship network. The findings of this paper have significant consequences for designing interventions that seek to harness social influence for collective action.     

Response of floodplain understorey species to environmental gradients and tree invasion: a functional trait perspective

Plants are connected to habitats by functional traits which are filtered by environmental gradients. Since tree species composition in the forest canopy can influence ecosystem processes by changing resource availability, litter accumulation, and soil nutrient content, we hypothesised that non-native invasive trees can establish new environmental filters on the understorey communities. In the hardwood floodplain forests in Northern Italy, the invasive trees Robinia pseudoacacia L. and Prunus serotina Ehrh. are the dominant canopy species. We used trait data assembled from databases and iterative RLQ analysis to identify a parsimonious set of functional traits responding to environmental variables (soil, light availability, disturbance, and stand structure) and the dominant native and invasive canopy species. Then, RLQ and fourth-corner analysis was conducted to investigate the joint structure between macro-environmental variables and species traits and functional groups were identified. The trait composition of the herb-layer was significantly related to the main environmental gradients and the presence of the invaders in the canopy showed significant relationships with several traits. In particular, the presence of P. serotina may mitigate or even erase the effect of disturbances, maintaining a stable forest microclimate and thus favouring ‘true’ forest species, while R. pseudoacacia may slow down forest succession and regeneration by establishing new stable associations with a graminoid-dominated understorey. The impact of the two invasive trees on herb layer composition appears to differ, indicating that different management and control strategies may be needed.     

Higher mental functions and the systems analysis of behavior under conditions of uncertainty

Superior psychical functions (skills) are usually formed in great subjective uncertainty conditions. Because of that exact knowledge of information mechanisms of behavior activity under uncertainty conditions is very importent. Some difficulties of traditional notions (classic behavior act model developed by P. K. Anokhin, systems quantization of behavior) are discussed. The model of probabilitive training allows to describe various training uncertainty conditions, and it operates as the Anokhin model in a specific case. The system-shaping factor in this model is an adaptive result. Afferent synthesis, aim for action, acceptor of the action result and the programme of actions have the traditional senses. Besides those it is proposed to use a concept of probability decision to alter the program of action, as well as an idea of memory buffer (results of search reactions). The organizational features of the functional system of behavior under great uncertainty conditions should be taken into account while specifying the informational mechanism responsible for systems quantization of behavior. The above mechanism can be used for explain the discreteness of an action in the program alteration process when the same quantum of behavior is implemented. These ideas are profitable for systems analysis of superior psychical functions, based on the reflex formation under environmental uncertainty conditions.     

Governing fisheries through the critical decade: the role and utility of polycentric systems

The next 10 years are considered a critical decade for fisheries. Declining fish stocks in combination with mounting climate pressure are likely to lead to significant and adverse socio-ecological impacts, threatening sustainability. Responding to these challenges requires modes of governance that are capable of dealing with the complexity and uncertainty associated with the world’s fisheries and their ecosystems. While a range of governance frameworks exist, the concept of polycentric governance has gained prominence in the environmental sector and is posited as a key principle underpinning the resilience of complex socio-ecological systems. However, the application of polycentric governance to fisheries management has been seldom explored. To examine this prospect, we review the literature on polycentric governance to elucidate its potential value in improving the outlook for fisheries and their associated ecosystems. We highlight a number of unique characteristics that overcome known limitations in other forms of governance—polycentric systems are highly participatory and promote the broadest levels of stakeholder involvement, they increase policy freedom at the local level, and they improve the spatial fit between knowledge, action and socio-ecological contexts to ensure that governance responses are implemented at the most appropriate scale. Through fisheries case-studies, we demonstrate that these characteristics are important in helping fisheries respond to complex challenges. Finally, we articulate key knowledge gaps that should be addressed through future research to understand the conditions under which polycentric governance systems are most suited, and the ways in which they can be operationalised most effectively.     

Governance of genetic biocontrol technologies for invasive fish

The modification of living agents for biological control can be collectively regarded as genetic biocontrol (GBC). Applications to invasive fish are an area of significant work in GBC, employing a diversity of techniques. Some of these techniques are governed by particular legislation, policy or treaty, (e.g., transgenesis), while others deliver agents with similar properties with minimal regulation. Together, this heterogeneity of governance and biology creates a number of challenges for effective use of GBC. In some cases, there are gaps and inconsistencies that pose real threats to biodiversity, and the long term sustainability of oversight arrangements as they currently stand is questionable. Researchers and would-be users of GBC for invasive fish must proactively engage with a variety of stakeholders to improve governance (in fish and other taxa), which we contend may include reconfiguration of relevant national governance systems, meaningful stakeholder dialogue and the creation of a new international treaty dedicated to biological control.     

Uncertainties in Predicting Species Distributions under Climate Change: A Case Study Using Tetranychus evansi (Acari: Tetranychidae), a Widespread Agricultural Pest

Many species are shifting their distributions due to climate change and to increasing international trade that allows dispersal of individuals across the globe. In the case of agricultural pests, such range shifts may heavily impact agriculture. Species distribution modelling may help to predict potential changes in pest distributions. However, these modelling strategies are subject to large uncertainties coming from different sources. Here we used the case of the tomato red spider mite (Tetranychus evansi), an invasive pest that affects some of the most important agricultural crops worldwide, to show how uncertainty may affect forecasts of the potential range of the species. We explored three aspects of uncertainty: (1) species prevalence; (2) modelling method; and (3) variability in environmental responses between mites belonging to two invasive clades of T. evansi. Consensus techniques were used to forecast the potential range of the species under current and two different climate change scenarios for 2080, and variance between model projections were mapped to identify regions of high uncertainty. We revealed large predictive variations linked to all factors, although prevalence had a greater influence than the statistical model once the best modelling strategies were selected. The major areas threatened under current conditions include tropical countries in South America and Africa, and temperate regions in North America, the Mediterranean basin and Australia. Under future scenarios, the threat shifts towards northern Europe and some other temperate regions in the Americas, whereas tropical regions in Africa present a reduced risk. Analysis of niche overlap suggests that the current differential distribution of mites of the two clades of T. evansi can be partially attributed to environmental niche differentiation. Overall this study shows how consensus strategies and analysis of niche overlap can be used jointly to draw conclusions on invasive threat considering different sources of uncertainty in species distribution modelling.     

The evolutionary ecology of deception

Through dishonest signals or actions, individuals often misinform others to their own benefit. We review recent literature to explore the evolutionary and ecological conditions for deception to be more likely to evolve and be maintained. We identify four conditions: (1) high misinformation potential through perceptual constraints of perceiver; (2) costs and benefits of responding to deception; (3) asymmetric power relationships between individuals and (4) exploitation of common goods. We discuss behavioural and physiological mechanisms that form a deception continuum from secrecy to overt signals. Deceptive tactics usually succeed by being rare and are often evolving under co‐evolutionary arms races, sometimes leading to the evolution of polymorphism. The degree of deception can also vary depending on the environmental conditions. Finally, we suggest a conceptual framework for studying deception and highlight important questions for future studies.     

Annual rhythms that underlie phenology: biological time-keeping meets environmental change

Seasonal recurrence of biological processes (phenology) and its relationship to environmental change is recognized as being of key scientific and public concern, but its current study largely overlooks the extent to which phenology is based on biological time-keeping mechanisms. We highlight the relevance of physiological and neurobiological regulation for organisms’ responsiveness to environmental conditions. Focusing on avian and mammalian examples, we describe circannual rhythmicity of reproduction, migration and hibernation, and address responses of animals to photic and thermal conditions. Climate change and urbanization are used as urgent examples of anthropogenic influences that put biological timing systems under pressure. We furthermore propose that consideration of Homo sapiens as principally a ‘seasonal animal’ can inspire new perspectives for understanding medical and psychological problems.     

“Wrong,but Useful”: Negotiating Uncertainty in Infectious Disease Modelling

For infectious disease dynamical models to inform policy for containment of infectious diseases the models must be able to predict; however, it is well recognised that such prediction will never be perfect. Nevertheless, the consensus is that although models are uncertain, some may yet inform effective action. This assumes that the quality of a model can be ascertained in order to evaluate sufficiently model uncertainties, and to decide whether or not, or in what ways or under what conditions, the model should be ‘used’. We examined uncertainty in modelling, utilising a range of data: interviews with scientists, policy-makers and advisors, and analysis of policy documents, scientific publications and reports of major inquiries into key livestock epidemics. We show that the discourse of uncertainty in infectious disease models is multi-layered, flexible, contingent, embedded in context and plays a critical role in negotiating model credibility. We argue that usability and stability of a model is an outcome of the negotiation that occurs within the networks and discourses surrounding it. This negotiation employs a range of discursive devices that renders uncertainty in infectious disease modelling a plastic quality that is amenable to ‘interpretive flexibility’. The utility of models in the face of uncertainty is a function of this flexibility, the negotiation this allows, and the contexts in which model outputs are framed and interpreted in the decision making process. We contend that rather than being based predominantly on beliefs about quality, the usefulness and authority of a model may at times be primarily based on its functional status within the broad social and political environment in which it acts.     

U.S. Environmental Protection Agency's revised guidelines for carcinogen risk assessment: evaluating a postulated mode of carcinogenic action in guiding dose–response extrapolation

There are new opportunities to using data from molecular and cellular studies in order to bring together a fuller biological understanding of how chemicals induce neoplasia. In 1996, the Environmental Protection Agency (EPA) published a proposal to replace its 1986 Guidelines for Carcinogen Risk Assessment to take advantage of these new scientific advances in cancer biology. The analytical framework within the new guidelines focuses on an understanding of the mode of carcinogenic action. Mode of action data come into play in a couple of ways in these new guidelines. For example, such information can inform the dose–response relationship below the experimental observable range of tumours. Thus, mode of action data can be useful in establishing more appropriate guidance levels for environmental contaminants. It is the understanding of the biological processes that lead to tumour development along with the response data derived from experimental studies that can help discern the shape of the dose–response at low doses (linear vs. nonlinear). Because it is experimentally difficult to establish “true thresholds” from others with a nonlinear dose–response relationship, the proposed guidelines take a practical approach to depart from low-dose linear extrapolation procedures when there is sufficient experimental support for a mode of action consistent with nonlinear biological processes (e.g., tumours resulting from the disruption of normal physiological processes).     

Performance and responses to competition in two congeneric annual species: does seed heteromorphism matter?

Variations in seed characteristics observed in heteromorphic species may affect various stages of their life cycles, e.g. seed dormancy, germination characteristics or even adult plant performance. Highly specialised seed morphs – described as colonisers and maintainers – exhibit a trade‐off between colonisation capacity and competitive traits. The performance of distinct seed morph progeny under competitive conditions, and especially in multi‐species arrangements, had previously not been given much attention. In this study, we compared performance and response to competition among distinct seed morph progenies in two congeneric, co‐occurring species: the invasive Bidens frondosa and the non‐invasive Bidens tripartita. We hypothesised that maintainer seed morphs of both species would perform better under increased plant densities and within inter‐morphic mixtures, while coloniser morphs would show stronger responses to increased densities and perform relatively poorly in inter‐morphic mixtures. We conducted a growth trial and a greenhouse experiment, which revealed that seed morph progeny differed significantly in plant height when grown without competition, while under competitive conditions such differences became less apparent. The observed pattern was more strongly pronounced in B. frondosa, which showed a general predominance in stature and biomass over its non‐invasive congener. Although seed morphs performed equally well under competitive conditions, increased plant height and more rapid germination can favour the maintainer seed morph on sites where vegetation is already present.     

A collaborative GIS method for integrating local and technical knowledge in establishing biodiversity conservation priorities

Methods for establishing biodiversity conservation priorities are urgently required, as the number of species and habitats that are threatened increases relative to the material resources available for their conservation. The identification of priority areas demands the integration of biophysical data on ecosystems together with social data on human pressures and planning opportunities. But comprehensive and reliable data are rarely available to demarcate where the need for action is most urgent and where the benefits of conservation strategies can be maximized. Strategic conservation initiatives cannot wait for the creation of comprehensive databases. In order to fill the missing data gaps, the combined knowledge of local and technical experts can be used. This study presents a collaborative geographic information system (GIS) method for integrating the knowledge of local and technical experts with existing spatial environmental data to establish priority areas for biodiversity conservation. Procedures for structuring and framing the discussions, establishing assessment criteria, integrating knowledge with data, and building consensus are incorporated into the method. The method provides a novel cooperative mechanism to aid spatial knowledge management and inclusive biodiversity planning.     

Dynamics of a stochastic predator-prey model with habitat complexity and prey aggregation

Interplay between predator and prey is a complex process in ecosystems due to its nature. The population dynamics can be affected by many extrinsic and intrinsic factors. In this paper, we make an attempt to uncover the effects from environmental disturbances when populations are subject to habitat complexity and aggregation effect. We firstly propose a stochastic predator-prey model with habitat complexity and aggregation efficiency for prey. We then mathematically analyze the model, to demonstrate the existence, uniqueness and the stochastically ultimately boundedness of the global positive solution, and to establish sufficient conditions for the existence of ergodic stationary distribution of the solution. We also establish sufficient conditions under which either only predator population dies out or the entire predator-prey model becomes extinct. Our theoretical and numerical results indicate that: (1) the environmental noises are disadvantage for the survival of biological populations; (2) when the density of prey is greater than one, prey aggregation can heighten the capability of predator species to capture prey and reduce the effect of environmental fluctuations, while when the density of prey is less than one, the results are opposite; (3) habitat complexity is propitious to the survival of prey population and may seriously threaten the persistence of the predator population.     

U.S. Environmental Protection Agency's revised guidelines for carcinogen risk assessment: evaluating a postulated mode of carcinogenic action in guiding dose-response extrapolation

There are new opportunities to using data from molecular and cellular studies in order to bring together a fuller biological understanding of how chemicals induce neoplasia. In 1996, the Environmental Protection Agency (EPA) published a proposal to replace its 1986 Guidelines for Carcinogen Risk Assessment to take advantage of these new scientific advances in cancer biology. The analytical framework within the new guidelines focuses on an understanding of the mode of carcinogenic action. Mode of action data come into play in a couple of ways in these new guidelines. For example, such information can inform the dose-response relationship below the experimental observable range of tumours. Thus, mode of action data can be useful in establishing more appropriate guidance levels for environmental contaminants. It is the understanding of the biological processes that lead to tumour development along with the response data derived from experimental studies that can help discern the shape of the dose-response at low doses (linear vs. nonlinear). Because it is experimentally difficult to establish "true thresholds" from others with a nonlinear dose-response relationship, the proposed guidelines take a practical approach to depart from low-dose linear extrapolation procedures when there is sufficient experimental support for a mode of action consistent with nonlinear biological processes (e.g., tumours resulting from the disruption of normal physiological processes).     

Risk-sensitive mating decisions in a visually compromised environment

Reproductive activities are often conspicuous and can increase the risk of predation. Evidence suggests that individuals are capable of responding to predators in a risk-sensitive manner. However, most studies tend to consider only the predator-mediated responses of males and females in isolation and with little regard to differences in local environmental conditions. Here, we experimentally investigate the effects of environmental visibility (turbidity) and predation risk on reproductive decisions in the sand goby, Pomatoschistus minutus, when exposed to a visually oriented predator, the European perch, Perca fluviatilis. We found that gobies were more reluctant to spawn in the predator''s presence, although larger males spawned sooner than smaller males. Interestingly, latency to spawning was unaffected by the visual environment, suggesting that gobies may be relying on non-visual cues under turbid conditions.     

A dominance‐based approach to map risks of ecological invasions in the presence of severe uncertainty

Aim Uncertainty has been widely recognized as one of the most critical issues in predicting the expansion of ecological invasions. The uncertainty associated with the introduction and spread of invasive organisms influences how pest management decision makers respond to expanding incursions. We present a model‐based approach to map risk of ecological invasions that combines two potentially conflicting goals: (1) estimating the likelihood of a new organism being established at a given locale and (2) quantifying the uncertainty of that prediction. Location Eastern and central Canada. Methods Our methodology focuses on the potential for long‐distance, human‐assisted spread of invasive organisms. First, we used a spatial simulation model to generate distributions of plausible invasion outcomes over a target geographical region. We then used second‐degree stochastic dominance (SSD) criteria to rank all geographical locations in the target region based on these distributions. We applied the approach to analyze pathways of human‐assisted spread (i.e., with commercially transported goods) of the emerald ash borer (EAB) (Agrilus planipennis Fairmaire), a major pest of ash trees in North America. Results The projected potential of the pest to establish at remote locations is significantly shaped by the amount of epistemic uncertainty in the model‐based forecasts. The estimates based on the SSD ranking identified major ‘crossroads’ through which the movement of the EAB with commercial transport is most likely to occur. The system of major expressways in Ontario and Quebec was confirmed as the primary gateway of the pest’s expansion throughout the Canadian landscape. Main conclusions Overall, the new approach generates more realistic predictions of long‐distance introductions than models that do not account for severe uncertainties and thus can help design more effective pest surveillance programmes. The modelling technique is generic and can be applied to assess other environmental phenomena when the level of epistemic uncertainty is high.     

Determination of elastic moduli of thin layers of soft material using the atomic force microscope

We address three problems that limit the use of the atomic force microscope when measuring elastic moduli of soft materials at microscopic scales. The first concerns the use of sharp cantilever tips, which typically induce local strains that far exceed the linear material regime. We show that this problem can be alleviated by using microspheres as probes, and we establish the criteria for their use. The second relates to the common use of the Hertz contact mechanics model, which leads to significant errors when applied to thin samples. We develop novel, simple to use corrections to apply for such cases. Samples that are either bonded or not bonded to a rigid substrate are considered. The third problem concerns the difficulty in establishing when contact occurs on a soft material. We obtain error estimates for the elastic modulus resulting from such uncertainty and discuss the sensitivity of the estimation methods to error in contact point. The theoretical and experimental results are compared to macroscopic measurements on poly(vinyl-alcohol) gels.     

Using and communicating uncertainty for the effective control of invasive non-native species

Estimates of quantities needed to plan invasive species control, such as population size, are always uncertain; this is an issue that can become a problem when mishandled in ecological science and its communication. The complexities of incorporating uncertainty into sophisticated decision-support tools may be a barrier to their use by decision makers, leading to decisions being made without due regard to uncertainty and risking misplaced certainty of predicted outcomes. We summarise ways in which uncertainty has been incorporated into and used to advise decisions on the management of invasive non-native species and other problem species, and offer a simple conceptual model for accommodating and using uncertainty at the planning stage. We also demonstrate how frequently uncertainty has been misused and miscommunicated in the wildlife management literature. We contend that uncertainty in estimates of natural quantities must be acknowledged, can inform decisions and can be made to derive decisions, and should not be ignored if invasive species policy is to be delivered effectively. Uncertainty must be communicated thoroughly and correctly by scientists if decision makers are to understand its consequences for planning and resourcing control programmes.     

Trait plasticity in species interactions: a driving force of community dynamics

Evolutionary community ecology is an emerging field of study that includes evolutionary principles such as individual trait variation and plasticity of traits to provide a more mechanistic insight as to how species diversity is maintained and community processes are shaped across time and space. In this review we explore phenotypic plasticity in functional traits and its consequences at the community level. We argue that resource requirement and resource uptake are plastic traits that can alter fundamental and realised niches of species in the community if environmental conditions change. We conceptually add to niche models by including phenotypic plasticity in traits involved in resource allocation under stress. Two qualitative predictions that we derive are: (1) plasticity in resource requirement induced by availability of resources enlarges the fundamental niche of species and causes a reduction of vacant niches for other species and (2) plasticity in the proportional resource uptake results in expansion of the realized niche, causing a reduction in the possibility for coexistence with other species. We illustrate these predictions with data on the competitive impact of invasive species. Furthermore, we review the quickly increasing number of empirical studies on evolutionary community ecology and demonstrate the impact of phenotypic plasticity on community composition. Among others, we give examples that show that differences in the level of phenotypic plasticity can disrupt species interactions when environmental conditions change, due to effects on realized niches. Finally, we indicate several promising directions for future phenotypic plasticity research in a community context. We need an integrative, trait-based approach that has its roots in community and evolutionary ecology in order to face fast changing environmental conditions such as global warming and urbanization that pose ecological as well as evolutionary challenges.     

Preadapted for invasiveness: do species traits or their plastic response to shading differ between invasive and non‐invasive plant species in their native range?

Aim Species capable of vigorous growth under a wide range of environmental conditions should have a higher chance of becoming invasive after introduction into new regions. High performance across environments can be achieved either by constitutively expressed traits that allow for high resource uptake under different environmental conditions or by adaptive plasticity of traits. Here we test whether invasive and non‐invasive species differ in presumably adaptive plasticity. Location Europe (for native species); the rest of the world and North America in particular (for alien species). Methods We selected 14 congeneric pairs of European herbaceous species that have all been introduced elsewhere. One species of each pair is highly invasive elsewhere in the world, particularly so in North America, whereas the other species has not become invasive or has spread only to a limited degree. We grew native plant material of the 28 species under shaded and non‐shaded conditions in a common garden experiment, and measured biomass production and morphological traits that are frequently related to shade tolerance and avoidance. Results Invasive species had higher shoot–root ratios, tended to have longer leaf‐blades, and produced more biomass than congeneric non‐invasive species both under shaded and non‐shaded conditions. Plants responded to shading by increasing shoot–root ratios and specific leaf area. Surprisingly, these shade‐induced responses, which are widely considered to be adaptive, did not differ between invasive and non‐invasive species. Main conclusions We conclude that high biomass production across different light environments pre‐adapts species to become invasive, and that this is not mediated by plasticities of the morphological traits that we measured.