Are several small wildlife crossing structures better than a single large? Arguments from the perspective of large wildlife conservation

Crossing structures for large wildlife are increasingly being constructed at major roads and railways in many countries and current guidelines for wildlife mitigation at linear infrastructures tend to advocate for large crossing structures sited at major movement corridors for the target species. The concept of movement corridors has, however, been challenged and pinching animal movements into bottlenecks entails risks. In this paper, I address the SLOSS dilemma of road ecology, i.e. the discussion whether a Single Large Or Several Small crossing structures along a linear barrier would produce the most benefit for wildlife, using the case of crossing structures for large wildlife in Sweden. I point out risks, ecological as well as practical, with investing in one large crossing structure and list a number of situations where it may be more beneficial to distribute the conservation efforts in the landscape by constructing several smaller crossing structures; for example, when the ecological knowledge is insufficient, when animal interactions are expected to be significant, when the landscape changes over time or when future human development cannot be controlled. I argue that such situations are often what infrastructure planning faces and that the default strategy, therefore, should be to distribute, rather than to concentrate passage opportunities along major transport infrastructures. I suggest that distributing passage opportunities over several smaller crossing structures would convey a risk diversification and that this strategy could facilitate the planning of wildlife mitigation. What to choose would however depend on, inter alia, landscape composition and ecology and on relationships amongst target species. A single large structure should be selected where it is likely that it can serve a large proportion of target animals and where the long-term functionality of the crossing structure can be guaranteed. New research is needed to support trade-offs between size and number of crossing structures. Cost-effectiveness analyses of wildlife crossing structures are currently rare and need to be further explored. Camera trapping and video surveillance of crossing structures provide opportunities to analyse details concerning, for example, any individual biases according to sex, age, status and grouping and any antagonism between species and individuals. Wildlife ecology research needs to better address questions posed by road and railway planning regarding the importance of specific movement routes and movement distances

Effectiveness of small road tunnels and fences in reducing amphibian roadkill and barrier effects at retrofitted roads in Sweden.

Schemes to reduce road impacts on amphibians have been implemented for decades in Europe, yet, several aspects on the effectiveness of such schemes remain poorly understood. Particularly in northern Europe, including Sweden, there is a lack of available information on road mitigation for amphibians, which is hampering implementation progress and cost-effectiveness analyses of mitigation options. Here, we present data derived from systematic counts of amphibians during spring migration at three previous hot-spots for amphibian roadkill in Sweden, where amphibian tunnels with guiding fences have been installed. We used the data in combination with a risk model to estimate the number of roadkills and successful crossings before vs. after mitigation and mitigated vs. adjacent non-mitigated road sections. In mitigated road sections, the estimated number of amphibians killed or at risk of being killed by car traffic decreased by 85-100% and the estimated number successfully crossing the road increased by 25-340%. Data, however, suggested fence-end effects that may moderate the reduction in roadkill. We discuss possible explanations for the observed differences between sites and construction types, and implications for amphibian conservation. We show how effectiveness estimates can be used for prioritizing amphibian passages along the existing road network. Finally, we emphasize the importance of careful monitoring of amphibian roadkill and successful crossings before and after amphibian passages are constructed

Renens användning av broar vid väg och järnväg

Den här rapporten redovisar renarnas användning av 12 st broar vid väg och järnväg i Norrbottens län, med tyngdpunkt på broar inom området för koncessionsrenskötsel. Broarna som studerats utgör en blandning av över- och underpassager, med olika dimensioner och utformning, varav några anlagda eller anpassade för fauna. Det främsta syftet med rapporten är att redovisa olika sätt att kvantifiera användningen och funktionen av broarna för renar, baserat på antal renar vid broarna (även fördelat mellan kön och åldrar), andel som passerar och beteenden. Rapporten ska kunna utgöra underlag för att ta fram systematiska mått för broars effektivitet för ren och renskötsel.Resultaten pekar inte på att något enskilt mått är bättre än andra; istället kan en möjlighet vara att kombinera olika mått. Det var stora variationerna över året i antal renar som besökte broarna och även i besökens karaktär (större antal passerande under årstidsvandring; ett fåtal som uppehöll sig vid broarna sommartid). Den aktuella förekomsten av ren i omgivningen behöver beaktas när renarnas användning av broar följs upp.Insamlade data (fotografier) erbjuder möjligheter till noggrannare analyser, särskilt av renarnas beteenden, vilket skulle kunna vägleda en ytterligare utveckling av funktionsmåtten

Situational adapting system supporting team situation awareness

ABSTRACT Military fighter pilots have to make suitable decisions fast in an environment where continuously increasing flows of information from sensors, team members and databases are provided. Not only do the huge amounts of data aggravate the pilots' decision making process: time-pressure, presence of uncertain data and high workload are factors that can worsen the performance of pilot decision making. In this paper, initial ideas of how to support the pilots accomplishing their tasks are presented. Results from interviews with two fighter pilots are described as well as a discussion about how these results can guide the design of a military fighter pilot decision support system, with focus on team cooperation

Why do top predators engage in superpredation? FRom an empirical scenario to a theoretical framework

Lethal interactions can shape ecosystem structure, and consequently understanding their causes is ecologically relevant. To improve both empirical and theoretical knowledge on superpredation (i.e. predation on high-order predators), we studied an eagle owl population, including its main prey and mesopredators, and then we crossed these results with existing theories to provide a reasoning framework. We ftted our feld data into four main causes explaining lethal interactions: food stress, opportunistic superpredation, removal of a competitor, and removal of a potential threat. Empirically, superpredation seemed to be mostly determined by the combination of the food-stress and opportunistic-superpredation hypotheses, which highlights the complexity of the factors triggering superpredation. Therefore, besides being a response to lower food availability, superpredation may also represent an effective mechanism to remove potential predators and/or competitors, either intentionally or not. Our theoretical framework focused on the decision-making process in superpredation, considering four inter-related stages: encountering; attacking; and capturing a mesopredator; as well as consuming a mesopredator once killed. Superpredation almost certainly results from a complex process of decision-making, accounting for costs and benefts assessed moment-to-moment and for each mesopredator individual. It is time to build bridges between theoretical and empirical studies to further understand the mechanisms driving complex interactions among top predators and mesopredators

Avian top predator and the landscape of fear: responses of mammalian mesopredators to risk imposed by the golden eagle

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Effects of an unexpected and expected event on older adults’ autonomic arousal and eye fixations during autonomous driving

© Copyright © 2020 Stephenson, Eimontaite, Caleb-Solly, Morgan, Khatun, Davis and Alford. Driving cessation for some older adults can exacerbate physical, cognitive, and mental health challenges due to loss of independence and social isolation. Fully autonomous vehicles may offer an alternative transport solution, increasing social contact and encouraging independence. However, there are gaps in understanding the impact of older adults’ passive role on safe human–vehicle interaction, and on their well-being. 37 older adults (mean age ± SD = 68.35 ± 8.49 years) participated in an experiment where they experienced fully autonomous journeys consisting of a distinct stop (an unexpected event versus an expected event). The autonomous behavior of the vehicle was achieved using the Wizard of Oz approach. Subjective ratings of trust and reliability, and driver state monitoring including visual attention strategies (fixation duration and count) and physiological arousal (skin conductance and heart rate), were captured during the journeys. Results revealed that subjective trust and reliability ratings were high after journeys for both types of events. During an unexpected stop, overt visual attention was allocated toward the event, whereas during an expected stop, visual attention was directed toward the human–machine interface (HMI) and distributed across the central and peripheral driving environment. Elevated skin conductance level reflecting increased arousal persisted only after the unexpected event. These results suggest that safety-critical events occurring during passive fully automated driving may narrow visual attention and elevate arousal mechanisms. To improve in-vehicle user experience for older adults, a driver state monitoring system could examine such psychophysiological indices to evaluate functional state and well-being. This information could then be used to make informed decisions on vehicle behavior and offer reassurance during elevated arousal during unexpected events