Circuit-theory applications to connectivity science and conservation

Conservation practitioners have long recognized ecological connectivity as a global priority for preserving biodiversity and ecosystem function. In the early years of conservation science, ecologists extended principles of island biogeography to assess connectivity based on source patch proximity and other metrics derived from binary maps of habitat. From 2006 to 2008, the late Brad McRae introduced circuit theory as an alternative approach to model gene flow and the dispersal or movement routes of organisms. He posited concepts and metrics from electrical circuit theory as a robust way to quantify movement across multiple possible paths in a landscape, not just a single least-cost path or corridor. Circuit theory offers many theoretical, conceptual, and practical linkages to conservation science. We reviewed 459 recent studies citing circuit theory or the open-source software Circuitscape. We focused on applications of circuit theory to the science and practice of connectivity conservation, including topics in landscape and population genetics, movement and dispersal paths of organisms, anthropogenic barriers to connectivity, fire behavior, water flow, and ecosystem services. Circuit theory is likely to have an effect on conservation science and practitioners through improved insights into landscape dynamics, animal movement, and habitat-use studies and through the development of new software tools for data analysis and visualization. The influence of circuit theory on conservation comes from the theoretical basis and elegance of the approach and the powerful collaborations and active user community that have emerged. Circuit theory provides a springboard for ecological understanding and will remain an important conservation tool for researchers and practitioners around the globe.     

Lower extremity injuries in children seated in forward facing child restraint systems

OBJECTIVE: The lower extremity is among the most frequently injured body regions for children restrained by forward facing child restraint systems (FFCRS), accounting for 28% of their clinically significant injuries, defined as AIS 2 and greater injuries excluding concussions. Despite the prevalence of these injuries, the current U.S. Motor Vehicle Safety Standard governing FFCRS (FMVSS 213) does not provide a direct assessment of the biomechanical risk of lower extremity fracture nor do the current pediatric test devices provide adequate instrumentation to detect the risk of such injuries. Before improvements can be made to the anthropometric test devices (ATDs) or test procedures to address these limitations, understanding of the sources and mechanisms of these injuries is necessary. Therefore, the objective of this study was to document location, source, and crash circumstances of lower extremity injuries in children seated in FFCRS. METHODS: Utilizing two sources of data, PCPS and CIREN, 20 in-depth investigations of crashes involving children seated in FFCRS with lower extremity injuries were reviewed to determine the nature of the injuries and the circumstances under which they occurred. RESULTS: Injuries below the knee were the most common, particularly to the tibia/fibula, and they most often occurred due to interaction with the vehicle seatback in front of the child's seating position. These injuries were sustained most commonly in frontal impacts although interaction with the seatback also occurred in other crash types. This interaction with the seatback was exacerbated by possible contributing factors such as intrusion of the front seatback into the child's occupant space or FFCRS misuse resulting in increased excursion of the child during impact. CONCLUSIONS: This review of cases of children in FFCRS with AIS 2 and greater lower extremity injury points to the role of the seatback in the occurrence of these injuries, suggesting the need to consider this interaction in the seatback design process and to adequately represent this interaction in regulatory procedures assessing the performance of child restraints.     

Building climate change resilience through local cooperation: a Peruvian Andes case study

Many of the problems faced by international projects intending to create adaptive social–ecological systems for climate change stem from lack of stakeholder engagement, limited understanding of local political, economic, and environmental complexities, and restricted time. Local organizations focused on conservation and development might have an advantage in creating adaptive social–ecological systems because they understand local processes and are involved with communities for extended periods of time. A local non-governmental organization, Asociación Ecosistemas Andinos (ECOAN), works in twenty-one communities in the Andean highlands outside of Cusco to conserve the endangered Polylepis forests. As part of the conservation project, ECOAN supports community-led development projects such as building greenhouses. Data for this project were gathered through interviews (with community members in three different communities, ECOAN staff, and donors) and participant observation. This paper shows that ECOAN’s extensive use of participation has led to community ownership of the conservation and development projects. The communities’ close connections to the Polylepis project contribute to resilience through creating networks, extending the local environmental ethic to the Polylepis trees, supporting projects that diversify and strengthen community sustenance, and contributing to the growth of economic activities. This case study provides a positive example of the potential for local organizations and people to take charge of their own resiliency efforts where international projects and protocols may otherwise prove ineffective.     

Use of standardized methods to improve extinction-risk classification

Standardized classification methods based on quantifiable risk metrics are critical for evaluating extinction threats because they increase objectivity, consistency, and transparency of listing decisions. Yet, in the United States, neither federal nor state agencies use standardized methods for listing species for legal protection, which could put listing decisions at odds with the magnitude of the risk. We used a recently developed set of quantitative risk metrics for California herpetofauna as a case study to highlight discrepancies in listing decisions made without standardized methods. We also combined such quantitative metrics with classification tree analysis to attempt to increase the transparency of previous listing decisions by identifying the criteria that had inherently been given the most weight. Federally listed herpetofauna in California scored significantly higher on the risk-metric spectrum than those not federally listed, whereas state-listed species did not score any higher than species that were not state listed. Based on classification trees, state endemism was the most important predictor of listing status at the state level and distribution trend (decline in a species’ range size) and population trend (decline in a species’ abundance at localized sites) were the most important predictors at the federal level. Our results emphasize the need for governing bodies to adopt standardized methods for assessing conservation risk that are based on quantitative criteria. Such methods allow decision makers to identify criteria inherently given the most weight in determining listing status, thus increasing the transparency of previous listing decisions, and produce an unbiased comparison of conservation threat across all species to promote consistency, efficiency, and effectiveness of the listing process.     

Assessing the impact of the U.S. Endangered Species Act recovery planning guidelines on managing threats for listed species

The Endangered Species Act (ESA) of the United States was enacted in 1973 to prevent the extinction of species. Recovery plans, required by 1988 amendments to the ESA, play an important role in organizing these efforts to protect and recover species. To improve the use of science in the recovery planning process, the Society for Conservation Biology (SCB) commissioned an independent review of endangered species recovery planning in 1999. From these findings, the SCB made key recommendations for how management agencies could improve the recovery planning process, after which the U.S. Fish and Wildlife Service and the National Marine Fisheries Service redrafted their recovery planning guidelines. One important recommendation called for recovery plans to make threats a primary focus, including organizing and prioritizing recovery tasks for threat abatement. We sought to determine the extent to which results from the SCB study were incorporated into these new guidelines and whether the SCB recommendations regarding threats manifested in recovery plans written under the new guidelines. Recovery planning guidelines generally incorporated the SCB recommendations, including those for managing threats. However, although recent recovery plans have improved in their treatment of threats, many fail to adequately incorporate threat monitoring. This failure suggests that developing clear guidelines for monitoring should be an important priority in improving ESA recovery planning.     

Connecting today's climates to future climate analogs to facilitate movement of species under climate change

Increasing connectivity is an important strategy for facilitating species range shifts and maintaining biodiversity in the face of climate change. To date, however, few researchers have included future climate projections in efforts to prioritize areas for increasing connectivity. We identified key areas likely to facilitate climate‐induced species’ movement across western North America. Using historical climate data sets and future climate projections, we mapped potential species’ movement routes that link current climate conditions to analogous climate conditions in the future (i.e., future climate analogs) with a novel moving‐window analysis based on electrical circuit theory. In addition to tracing shifting climates, the approach accounted for landscape permeability and empirically derived species’ dispersal capabilities. We compared connectivity maps generated with our climate‐change‐informed approach with maps of connectivity based solely on the degree of human modification of the landscape. Including future climate projections in connectivity models substantially shifted and constrained priority areas for movement to a smaller proportion of the landscape than when climate projections were not considered. Potential movement, measured as current flow, decreased in all ecoregions when climate projections were included, particularly when dispersal was limited, which made climate analogs inaccessible. Many areas emerged as important for connectivity only when climate change was modeled in 2 time steps rather than in a single time step. Our results illustrate that movement routes needed to track changing climatic conditions may differ from those that connect present‐day landscapes. Incorporating future climate projections into connectivity modeling is an important step toward facilitating successful species movement and population persistence in a changing climate.     

Safety evaluation of cable barriers installation on rural highways in British Columbia

Objective: The objective of this study was to evaluate the safety effectiveness of cable barrier systems installation on rural highway sections in British Columbia, Canada.

Methods: Data on police-attended serious collisions (injury?+?fatality) on a number of rural highway sections in British Columbia, Canada, were used in the analysis. An empirical Bayes (EB) approach was employed to ensure that the evaluation results were reliable and to account for the regression to the mean artifact. Safety performance functions (SPFs) were developed using data collected at similar sites. For both median cable barrier (MCB) and roadside cable barrier (RCB) sections, the evaluation was undertaken using all serious collisions, truck serious collisions, and off-road serious collisions.

Results: For MCB sections, the evaluation results showed statistically significant reductions of 21.7, 53.8, and 34.8% in all serious collisions, truck serious collisions, and off-road left (ORL) combined with head-on (HO) serious collisions. For RCB sections, statistically significant reductions of 74.7, 100, and 100% were found in all serious collisions, truck serious collisions, and off-road right (ORR) serious collisions, respectively. The impact of the after period on the evaluation results was explored. It was found that the changes in safety become more stable using an after period of 2–5 years.

Conclusions: Cable barriers were successful in reducing the frequency of serious collisions on provincial highways in British Columbia.     

Secondary succession dynamics in estuarine marshes across landscape-scale salinity gradients

Secondary succession plays a critical role in driving community structure in natural communities, yet how succession dynamics vary with environmental context is generally unknown. We examined the importance of seedling and vegetative recruitment in the secondary succession of coastal marsh vegetation across a landscape-scale environmental stress gradient. Replicate bare patches were initiated in salt, brackish, and oligohaline marshes in Narragansett Bay, Rhode Island, USA, and allowed to recover unmanipulated or with colonizing seedlings or vegetative runners removed for three years. Seed dispersal and seed bank studies were conducted at the same sites. We found that rates of recovery were 3-10 times faster in brackish and oligohaline marshes than in salt marshes. The fast pace of recovery in oligohaline marshes was driven by seedling colonization, while recovery was dominated by vegetative runners in brackish marshes and by both seedlings and runners in salt marshes. Seed and seedling availability was much greater in oligohaline marshes with up to 24 times the seed bank density compared with salt marshes. In contrast to the facilitated succession generally found in salt marshes, oligohaline marshes follow the tolerance model of succession where numerous species colonize from seed and are slowly displaced by clonal grasses whose recovery is slowed by preemptive competition from seedlings, contributing to the higher species diversity of oligohaline marshes. These findings reveal fundamental differences in the dynamics and assembly of marsh plant communities along estuarine salinity gradients that are important for conceptually understanding wetlands and for guiding the management and restoration of various types of coastal marshes.     

Differential toxicity of silver and titanium dioxide nanoparticles on Drosophila melanogaster development, reproductive effort, and viability: size, coatings and antioxidants matter

Silver and titanium dioxide nanoparticles are known to induce oxidative stress in vitro and in vivo. Here we test if they impact development, mating success, and survivorship in Drosophila melanogaster, and if so, if these effects are reversible by antioxidants. Ingestion of nanotitanium dioxide during the larval stage of the life cycle showed no effects on development or survivorship, up to doses of 200 μg mL⁻¹. Conversely, ingestion of nanosilver had major dose, size, and coating-dependent effects on each of these aspects of life history. Each of these effects was partially or fully reversible by vitamin C. Larvae growing on nanosilver supplemented with vitamin C showed a greater than twofold increase in survivorship compared to flies reared on nanosilver alone, and a threefold increase in mating success. Vitamin C also rescued cuticular and pigmentation defects in nanosilver fed flies. Biochemical assays of superoxide dismutase and glutathione show these markers respond to nanotitanium dioxide and nanosilver induced oxidative stress, and this response is reduced by vitamin C. These results indicate that life history effects of nanosilver ingestion result from oxidative stress, and suggest antioxidants as a potential remediation for nanosilver toxicity. Conversely, the lack of nanotitanium dioxide life history toxicity shows that oxidative stress does not necessarily result in whole organism effects, and argues that nanoparticle toxicity needs to be examined at different levels of biological organization.     

Creating conservation strategies with value-focused thinking

Biodiversity and human well-being strategies are only as good as the set of ideas people think about. We evaluated value-focused thinking (VFT), a framework that emphasizes creating objectives and strategies that are responsive to the objectives. We performed a proof-of-concept study of VFT with 6 conservation planning teams at a global conservation organization. We developed a package of materials related to VFT, including meeting–session agendas, a virtual facilitation template, facilitator's guide, and evaluation questionnaires. We used these materials to test whether VFT applied in a group setting resulted in high-quality conservation strategies and participant satisfaction and whether our materials were scalable, meaning that someone newly trained in VFT could facilitate planning meetings that resulted in high-quality strategies and participant satisfaction, as compared with an experienced VFT facilitator. Net response indicated positive compelling, feasible, creative, and representative ratings for the conservation strategies per team. Participants indicated satisfaction overall, although satisfaction was greater for objectives than for strategies. Among the participants with previous conservation planning experience, all were at least as satisfied with their VFT strategies compared with previously developed strategies, and none were less satisfied (p = 0.001). Changes in participant satisfaction were not related to facilitator type (experienced or inexperienced with VFT) (p > 0.10). Some participants had a preconceived sense of shared understanding of important values and interests before participating in the study, which VFT strengthened. Our results highlight the advantages of structuring the development and evaluation of conservation planning frameworks around VFT.