Using multilevel spatial models to understand salamander site occupancy patterns after wildfire

Studies of the distribution of elusive forest wildlife have suffered from the confounding of true presence with the uncertainty of detection. Occupancy modeling, which incorporates probabilities of species detection conditional on presence, is an emerging approach for reducing observation bias. However, the current likelihood modeling framework is restrictive for handling unexplained sources of variation in the response that may occur when there are dependence structures such as smaller sampling units that are nested within larger sampling units. We used multilevel Bayesian occupancy modeling to handle dependence structures and to partition sources of variation in occupancy of sites by terrestrial salamanders (family Plethodontidae) within and surrounding an earlier wildfire in western Oregon, USA. Comparison of model fit favored a spatial N-mixture model that accounted for variation in salamander abundance over models that were based on binary detection/non-detection data. Though catch per unit effort was higher in burned areas than unburned, there was strong support that this pattern was due to a higher probability of capture for individuals in burned plots. Within the burn, the odds of capturing an individual given it was present were 2.06 times the odds outside the burn, reflecting reduced complexity of ground cover in the burn. Ther was weak support that true occupancy was lower within the burned area. While the odds of occupancy in the burn were 0.49 times the odds outside the burn among the five species, the magnitude of variation attributed to the burn was small in comparison to variation attributed to other landscape variables and to unexplained, spatially autocorrelated random variation. While ordinary occupancy models may separate the biological pattern of interest from variation in detection probability when all sources of variation are known, the addition of random effects structures for unexplained sources of variation in occupancy and detection probability may often more appropriately represent levels of uncertainty.     

Timing and flight mode of departure in migrating European bee-eaters in relation to multi-scale meteorological processes

Understanding departure decisions of migratory birds and the environmental factors affecting them is important for predicting their distribution, abundance, and arrival times to breeding and wintering areas. In the past, methodological difficulties to obtain fine-scale bird departure and meteorological data have limited testing the multi-scale effects of meteorology on bird departure during migration. We investigated departure timing of European bee-eaters (Merops apiaster) staging in southern Israel, identified their departure flight mode (flapping or soaring) using radio telemetry, and measured local meteorological conditions to study if bird departure was affected by these. Departure timing was examined using a timescale analysis design. The conditions before, during, and after the time of departure were compared using timescales of 24 h, 6 h, 1 h, and 10 min and in relation to bird flight mode. At the between-days timescale, barometric pressure at departure time was significantly lower compared with 2–1 day earlier, whereas temperature at departure was significantly higher compared with 3–2 days earlier. Temperature at departure was also higher compared with 6 h and 3–2 h earlier. Tailwind assistance had no significant effect at any timescale. Soaring birds departed at significantly higher temperature compared with flapping birds. We suggest that bee-eater departure is tuned to the infrequent passage of warm atmospheric depressions at the between-days timescale and with an increasing temperature trend within these days enabling the birds to use energetically cheap soaring flight. We thus suggest that energetic considerations dictate the departure decisions of migrating European bee-eaters.     

Sexual selection based on egg colour: physiological models and egg discrimination experiments in a cavity-nesting bird

It has been proposed that the blue-green bird egg colourations of many avian species may constitute a sexually selected female signal that males can use to modulate their parental investment. A fundamental untested assumption for the validation of this hypothesis is that males can accurately assess differences in the colour of eggs. A recent review suggests that this could be particularly problematic when egg clutches were located within a dimly lit nest cavity, due to limitations of the visual system in low light conditions. Here, we first used a photoreceptor noise-limited model of colour discrimination ability that accounts for visual performance under low light conditions to study whether a typical cavity-nesting passerine, the spotless starling Sturnus unicolor, can discriminate their eggs under the ambient illumination in their nest-holes. Secondly, we tested the validity of model predictions with behavioural data collected in two egg discrimination experiments performed in this species. Estimated egg detectability depended entirely on model assumptions about visual limitations linked to light intensity. Starlings would not be able to discriminate egg differences in their nests if the model was based on the assumption that light intensity limited detectability, whereas they could potentially perceive as different many possible pairwise clutch comparisons if the model assumption was that light intensity did not limit detectability. Results of behavioural experiments fitted the prediction of the visual model where light intensity did not limit detectability. Our results suggest that photoreceptor noise-limited colour models based on stimulation of single photoreceptors cannot, at present, be used to predict egg discrimination ability in spotless starlings under low light conditions. Future studies aiming to test egg discrimination constraints in the frame of the sexual selection hypothesis should therefore combine both modelling and behavioural experiments to determine which are the components of the models that produce the mismatch with the behavioural conditions.     

Impact of land-cover change in the Southern Amazonia climate: a case study for the region of Alta Floresta,Mato Grosso,Brazil

The transformation of forest into pastures in the Brazilian Amazon leads to significant consequences to climate at local scale. In the region of Alta Floresta (Mato Grosso, Brazil), deforestation has been intense with over half the forests being cut since 1970. This article first examines the evolution of precipitation observed in this region and shows a significant trend in the decrease in total precipitation especially at the end of the dry season and at the beginning of the rainy season. The study then compares the temperatures measured in cleared and forested sectors within a reserve in the area of Alta Floresta (Mato Grosso, Brazil) between 2006 and 2007. The cleared sector was always hotter and drier (from 5% to 10%) than the forested area. This difference was not only especially marked during the day when it reached on average 2°C but also seemed to increase during the night with the onset of the dry season (+0.5°C). The Urban Heat Island effect is also evident especially during the night and in the dry season.     

PFAS Experts Symposium: Statements on regulatory policy,chemistry and analytics,toxicology, transport/fate,and remediation for per‐ and polyfluoroalkyl substances (PFAS) contamination issues

Sixty leading members of the scientific, engineering, regulatory, and legal communities assembled for the PFAS Experts Symposium in Arlington, Virginia on May 20 and 21, 2019 to discuss issues related to per‐ and polyfluoroalkyl substances (PFAS) based on the quickly evolving developments of PFAS regulations, chemistry and analytics, transport and fate concepts, toxicology, and remediation technologies.  The Symposium created a venue for experts with various specialized skills to provide opinions and trade perspectives on existing and new approaches to PFAS assessment and remediation in light of lessons learned managing other contaminants encountered over the past four decades. The following summarizes several consensus points developed as an outcome of the Symposium:

• Regulatory and policy issues: The response by many states and the US Environmental Protection Agency (USEPA) to media exposure and public pressure related to PFAS contamination is to relatively quickly initiate programs to regulate PFAS sites. This includes the USEPA establishing relatively low lifetime health advisory levels for PFAS in drinking water and even more stringent guidance and standards in several states. In addition, if PFAS are designated as hazardous substances at the federal level, as proposed by several Congressional bills, there could be wide‐reaching effects including listing of new Superfund sites solely for PFAS, application of stringent state standards, additional characterization and remediation at existing sites, reopening of closed sites, and cost renegotiation among PRPs.
• Chemistry and analytics: PFAS analysis is confounded by the lack of regulatory‐approved methods for most PFAS in water and all PFAS in solid media and air, interference with current water‐based analytical methods if samples contain high levels of suspended solids, and sample collection and analytical interference due to the presence of PFAS in common consumer products, sampling equipment, and laboratory materials.
• Toxicology and risk: Uncertainties remain related to human health and ecological effects for most PFAS; however, regulatory standards and guidance are being established incorporating safety factors that result in part per trillion (ppt) cleanup objectives. Given the thousands of PFAS that may be present in the environment, a more appropriate paradigm may be to develop toxicity criteria for groups of PFAS rather than individual PFAS.
• Transport and fate: The recalcitrance of many perfluoroalkyl compounds and the capability of some fluorotelomers to transform into perfluoroalkyl compounds complicate conceptual site models at many PFAS sites, particularly those involving complex mixtures, such as firefighting foams. Research is warranted to better understand the physicochemical properties and corresponding transport and fate of most PFAS, of branched and linear isomers of the same compounds, and of the interactions of PFAS with other co‐contaminants such as nonaqueous phase liquids. Many PFAS exhibit complex transport mechanisms, particularly at the air/water interface, and it is uncertain whether traditional transport principles apply to the ppt levels important to PFAS projects. Existing analytical methods are sufficient when combined with the many advances in site characterization techniques to move rapidly forward at selected sites to develop and test process‐based conceptual site models.
• Existing remediation technologies and research: Current technologies largely focus on separation (sorption, ion exchange, or sequestration). Due to diversity in PFAS properties, effective treatment will likely require treatment trains. Monitored natural attenuation will not likely involve destructive reactions, but be driven by processes such as matrix diffusion, sorption, dispersion, and dilution.

The consensus message from the Symposium participants is that PFAS present far more complex challenges to the environmental community than prior contaminants. This is because, in contrast to chlorinated solvents, PFAS are severely complicated by their mobility, persistence, toxicological uncertainties, and technical obstacles to remediation—all under the backdrop of stringent regulatory and policy developments that vary by state and will be further driven by USEPA. Concern was expressed about the time, expense, and complexity required to remediate PFAS sites and whether the challenges of PFAS warrant alternative approaches to site cleanups, including the notion that adaptive management and technical impracticability waivers may be warranted at sites with expansive PFAS plumes. A paradigm shift towards receptor protection rather than broad scale groundwater/aquifer remediation may be appropriate.     

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.     

Expert System for Terrestrial Vegetation Distribution, Potential Impact and Mitigation Abatement Measures

The tropical rainforest of Malaysia holds one of the richest flora in the world. The favourable climate has produced flora of amazing richness and variety. Terrestrial vegetation of tropical rainforests is an important feature of the environment. Plants play a major role in the environment and conservation of a particular environment depends fundamentally on the maintenance of existing plants and their communities and hierarchies. Interference in the balance of the ecosystem may produce radical changes that lead to progressive deviations from the original situation. Therefore, the application of a computer technology in the form of an expert system (ES) will be able to help in the analysis and management of the EIA information. The ES is named VEGEVIC. Application of the system will lead to greater consistency in the application of EIA through implementation of a standard approach.     

Ecological scenario planning and the question of the best regime in the political theory of Hans Jonas

In The Imperative of Responsibility, Hans Jonas elevates the practice of ecological scenario planning in political analysis. Not only does he provide an ethical justification for ecological scenario planning, but he also uses it as a means to discern an ethical imperative for the technological age. Jonas engages in regime analysis while keeping before him a vision of the worst-case ecological scenario, a combination that is morally and politically necessary due to the colossal consequences of cumulative human actions. Jonas’s work thus provides a good, even necessary, starting point for examining the relevance of scenario planning for environmental political theory.     

Urban stormwater runoff pollutant loadings: GIS land use classification vs. sample-based predictions

Environmental Science and Pollution Research - Cities are growing worldwide with an increase in stormwater quantity and decrease in quality, negatively impacting receiving water bodies. The...