Elevated CO2 affects the behavior of an ecologically and economically important coral reef fish

We tested the effect of near-future CO₂ levels (≈490, 570, 700, and 960 μatm CO₂) on the olfactory responses and activity levels of juvenile coral trout, Plectropomus leopardus, a piscivorous reef fish that is also one of the most important fisheries species on the Great Barrier Reef, Australia. Juvenile coral trout reared for 4 weeks at 570 μatm CO₂ exhibited similar sensory responses and behaviors to juveniles reared at 490 μatm CO₂ (control). In contrast, juveniles reared at 700 and 960 μatm CO₂ exhibited dramatically altered sensory function and behaviors. At these higher CO₂ concentrations, juveniles became attracted to the odor of potential predators, as has been observed in other reef fishes. They were more active, spent less time in shelter, ventured further from shelter, and were bolder than fish reared at 490 or 570 μatm CO₂. These results demonstrate that behavioral impairment of coral trout is unlikely if pCO₂ remains below 600 μatm; however, at higher levels, there are significant impacts on juvenile performance that are likely to affect survival and energy budgets, with consequences for predator–prey interactions and commercial fisheries.     

When three per cent may not be three per cent; device-equipped seabirds experience variable flight constraints

Current guidelines for instrumenting birds state that external devices should not exceed 3–5% of the birds’ body mass; however, the energetic consequences of carrying any given device mass are likely to vary according to the morphology and ecology of the species concerned. We used a freeware program to estimate the mechanical power requirements of flight at the minimum power speed for 80 species of flying seabird from 8 major groups with payloads of increasing mass. Devices representing 3% of the bird’s body mass resulted in an increase in energy expenditure for flight ranging from 4.67 to 5.71% without accounting for the increase in body drag coefficient associated with external devices. This effect differed within and between seabird lineages with members of the Alcidae and Phalacrocoracidae experiencing the highest energetic costs of any increase in device mass. We propose that device effects on seabirds could be further reduced through consideration of species-specific effects of added payload and drag.     

The importance of space, time, and stochasticity to the demography and management of Alliaria petiolata

As population modeling is increasingly called upon to guide policy and management, it is important that we understand not only the central tendencies of our study systems, but the consequences of their variation in space and time as well. The invasive plant Alliaria petiolata (garlic mustard) is actively managed in the United States and is the focus of a developing biological control program. Two weevils (Coleoptera: Curculionidae: Ceutorhynchus) that reduce fecundity (C. alliariae) and rosette survival plus fecundity (C. scrobicollis) are under consideration for release pending host specificity testing. We used a demographic modeling approach to (1) quantify variability in A. petiolata growth and vital rates and (2) assess the potential for single- or multiple-agent biocontrol to suppress growth of 12 A. petiolata populations in Illinois and Michigan studied over three plant generations. We used perturbation analyses and simulation models with stochastic environments to estimate stochastic growth rates (lambda(S)) and predict the probability of successful management using either a single biocontrol agent or two agent species together. Not all populations exhibited invasive dynamics. Estimates of lambda(S) ranged from 0.78 to 2.21 across sites, while annual, deterministic growth (lambda) varied up to sevenfold within individual sites. Given our knowledge of the biocontrol agents, this analysis suggests that C. scrobicollis alone may control A. petiolata at up to 63% of our study sites where lambda >1, with the combination of both agents predicted to succeed at 88% of sites. Across sites and years, the elasticity rankings were dependent on lambda. Reductions of rosette survival, fecundity, or germination of new seeds are predicted to cause the greatest reduction of lambda in growing populations. In declining populations, transitions affecting seed bank survival have the greatest effect on lambda. This contrasts with past analyses that varied parameters individually in an otherwise constant matrix, which may yield unrealistic predictions by decoupling natural parameter covariances. Overall, comparisons of stochastic and deterministic growth rates illustrate how analyses of individual populations or years could misguide management or fail to characterize complex traits such as invasiveness that emerge as attributes of populations rather than species.     

Modeling range dynamics in heterogeneous landscapes: invasion of the hemlock woolly adelgid in eastern North America

Range expansion by native and exotic species will continue to be a major component of global change. Anticipating the potential effects of changes in species distributions requires models capable of forecasting population spread across realistic, heterogeneous landscapes and subject to spatiotemporal variability in habitat suitability. Several decades of theory and model development, as well as increased computing power and availability of fine-resolution GIS data, now make such models possible. Still unanswered, however, is the question of how well this new generation of dynamic models will anticipate range expansion. Here we develop a spatially explicit stochastic model that combines dynamic dispersal and population processes with fine-resolution maps characterizing spatiotemporal heterogeneity in climate and habitat to model range expansion of the hemlock woolly adelgid (HWA; Adelges tsugae). We parameterize this model using multiyear data sets describing population and dispersal dynamics of HWA and apply it to eastern North America over a 57-year period (1951-2008). To evaluate the model, the observed pattern of spread of HWA during this same period was compared to model predictions. Our model predicts considerable heterogeneity in the risk of HWA invasion across space and through time, and it suggests that spatiotemporal variation in winter temperature, rather than hemlock abundance, exerts a primary control on the spread of HWA. Although the simulations generally matched the observed current extent of the invasion of HWA and patterns of anisotropic spread, it did not correctly predict when HWA was observed to arrive in different geographic regions. We attribute differences between the modeled and observed dynamics to an inability to capture the timing and direction of long-distance dispersal events that substantially affected the ensuing pattern of spread.     

使用Xevo TQ-S和APGC(大气压气相色谱)大幅降低二噁英分析中的样品残留

当有机化合物在含有氯的环境下燃烧时,会产生二噁英和呋喃,例如聚氯乙烯(PVC)生产、纸张漂白过程,以及火山爆发等自然原因.二噁英是剧毒物质,并且具有亲脂性,很容易在多种动物体内积累.它们还是潜在的诱变剂和致癌物质.2,3,7,8-四氯二苯并二噁英(TCDD)结构如下:Xevo TQ-S和大气压气相色谱(APGC)组成了一个非常灵敏的检测系统,可以准确测定出限制浓度的二噁英和呋喃.在分析未知浓度的样品时,可能会检测到浓度非常高的化合物.因此,目标化合物的存在会对下一次进样造成样品残留,进而导致定量结果有误.     

Socially facilitated antipredator behavior by ringed salamanders (<Emphasis Type="Italic">Ambystoma annulatum</Emphasis>)

Many aspects of animal behavior can be socially facilitated, including foraging behavior, exploration behavior, and antipredator behavior. Although larvae of the ringed salamander (Ambystoma annulatum) are not gregarious, they can live in high densities and face intense predation pressure during a short period following hatching. In a predator-recognition experiment, we found that these salamanders responded to chemical cues from dragonfly nymphs (Family: Libellulidae) with appropriate antipredator behavior (decreased activity), and this response was absent when salamanders were exposed to chemical cues from nonpredatory mayfly nymphs (Family: Heptageniidae). In a second experiment, we tested whether antipredator behavior in response to chemical cues of dragonflies could be socially facilitated by larval ringed salamanders. We placed an “observer” salamander into a central arena with four “demonstrator” salamanders behind clear barriers around an arena. The barriers ensured that chemical cues would not be detected by the observer. When demonstrators were exposed to chemical cues from dragonflies, the data were consistent with the hypothesis that both demonstrators and observers decreased activity relative to a blank control. Our results provide evidence that social facilitation can occur in larval ringed salamanders, a nonsocial species.     

Ecological boundary detection using Bayesian areal wombling

The study of ecological boundaries and their dynamics is of fundamental importance to much of ecology, biogeography, and evolution. Over the past two decades, boundary analysis (of which wombling is a subfield) has received considerable research attention, resulting in multiple approaches for the quantification of ecological boundaries. Nonetheless, few methods have been developed that can simultaneously (1) analyze spatially homogenized data sets (i.e., areal data in the form of polygons rather than point-reference data); (2) account for spatial structure in these data and uncertainty associated with them; and (3) objectively assign probabilities to boundaries once detected. Here we describe the application of a Bayesian hierarchical framework for boundary detection developed in public health, which addresses these issues but which has seen limited application in ecology. As examples, we analyze simulated spread data and the historic pattern of spread of an invasive species, the hemlock woolly adelgid (Adelges tsugae), using county-level summaries of the year of first reported infestation and several covariates potentially important to influencing the observed spread dynamics. Bayesian areal wombling is a promising approach for analyzing ecological boundaries and dynamics related to changes in the distributions of native and invasive species.     

A far-near sparse covariance model with application in climatology

Environmental and Ecological Statistics - Teleconnection, the strong dependence between two distant locations, provides interesting information for discovering the structures in spatial data. While...     

Keeping pace with forestry: Multi-scale conservation in a changing production forest matrix

The multi-scale approach to conserving forest biodiversity has been used in Sweden since the 1980s, a period defined by increased reserve area and conservation actions within production forests. However, two thousand forest-associated species remain on Sweden’s red-list, and Sweden’s 2020 goals for sustainable forests are not being met. We argue that ongoing changes in the production forest matrix require more consideration, and that multi-scale conservation must be adapted to, and integrated with, production forest development. To make this case, we summarize trends in habitat provision by Sweden’s protected and production forests, and the variety of ways silviculture can affect biodiversity. We discuss how different forestry trajectories affect the type and extent of conservation approaches needed to secure biodiversity, and suggest leverage points for aiding the adoption of diversified silviculture. Sweden’s long-term experience with multi-scale conservation and intensive forestry provides insights for other countries trying to conserve species within production landscapes.

     

High-resolution mass spectrometry analysis of secondary organic aerosol generated by ozonolysis of isoprene

The chemical composition of secondary organic aerosol (SOA) generated from the ozonolysis of isoprene (C₅H₈) in the presence of an OH scavenger was examined using high-resolution electrospray ionization mass spectrometry (ESI-MS) in the mass range m/z = 50–1000. The chemical composition of SOA is complex, with more than 1000 assigned peaks observed in the positive and negative ion mode spectra. Only a small fraction of peaks correspond to known products of isoprene oxidation, such as pyruvic acid, glycolic acid, methylglyoxal, etc. The absolute majority of the detected peaks correspond to highly oxidized oligomeric constituents of SOA, with an average O:C molar ratio of 0.6. The corresponding organic mass (OM) to organic oxygen (OO) ratio is 2.4. Approximately 8% of oxygen atoms in SOA are in the form of peroxides, as quantified with an iodide test. Double bond equivalency (DBE) factors, representing the sum of all double bonds and rings, increase by 1 for every 1–2 additional carbon atoms in the molecule. The number of unoxidized CC double bonds is estimated to be less than 10%; the remaining DBE is due to CO carbonyl groups. Kendrick analysis suggests that the prevalent oligomer building blocks are small carbonyls with a C₁–C₂ skeleton. Formaldehyde (CH₂O) is identified as the most common repetitive building block in the observed oligomeric compounds.