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Outcomes of predator–prey interactions depend on biotic and abiotic factors. Habitat complexity, for example, mediates predator functional response type and parameters (attack rate and handling time). However, the relationship between habitat complexity and functional response varies across ecosystems. We assessed interactions between the giant water bug, Belostoma sp., and its prey, rams-horn snails, Helisoma trivolvis, across four prey densities (N = 2, 4, 8, 16 snails) and three habitat complexity levels (No-complexity, Low-complexity, High-complexity) to understand how complexity affected the functional response. We also tested effects of predator and prey body size on number of prey killed. Belostoma exhibited a Type III functional response in all habitat complexity treatments. Attack rate tended to increase with increasing complexity. Handling time was different among treatments, being lowest in the No-complexity treatment and highest in the Low-complexity treatment. Belostoma body size was positively related, while Helisoma body size was inversely related, to the number of Helisoma killed. We show habitat complexity does not affect the shape of predator functional response but impacts response parameters in the Belostoma–Helisoma system. We reaffirm that attack rate, handling time, and mortality outcomes for prey within predator–prey interactions are affected by abiotic factors through habitat complexity.

Phenology is a key driver of population and community dynamics. Phenological metrics (e.g., first date that an event occurred) often simplify information from the full phenological distribution, which may undermine efforts to determine the importance of life history events. Data regarding full phenological distributions are especially needed as many species are shifting phenology with climatic change which can alter life-history patterns and species dynamics. We tested whether skewness, kurtosis or maximum duration of breeding phenology affected juvenile emigration phenology and survival in natural populations of ringed (Ambystoma annulatum) and spotted salamanders (A. maculatum) spanning a 7-year period at two study locations. We evaluated the relative importance of different phenological metrics in breeding phenology and larval density dependence on emigration phenology and survival. We found that variability in emigration phenology differed by species, with ringed salamanders having a shorter duration and distributions that were more often right-skewed and leptokurtic compared to spotted salamanders. Emigration phenology was not linked to any measure of variability in breeding phenology, indicating phenological variability operates independently across life stages and may be subject to stage-specific influences. Emigration duration and skewness were partially explained by larval density, which demonstrates how phenological distributions may change with species interactions. Further tests that use the full phenological distribution to link variability in timing of life history events to demographic traits such as survival are needed to determine if and how phenological shifts will impact species persistence.

Direct and indirect effects both influence population and community dynamics. The relative strengths of these pathways are often compared using experimental approaches, but their evaluation in situ has been less frequent. We examined how individual and aggregate impacts of direct and indirect effects of species densities, proxies for competition and predation pressure, and habitat variables influenced patterns of larval density and body size of ringed (Ambystoma annulatum) and spotted salamanders (A. maculatum). We surveyed > 150 ponds in Missouri, USA, from 2012 to 2014 to measure the density and body size of each focal species, the density of co-occurring pond food web members, and select habitat features. We used structural equation modeling to quantify the relative importance of direct and indirect pathways on both body size and larval density. Overall, both responses were explained through a combination of direct and indirect effects. However, the magnitudes of direct effects were often greater than indirect effects. Some of the direct and indirect relationships with larval salamander size and density were also consistent with results from experimental studies. Finally, total direct and indirect effects were often weaker due to habitat and density variables negating each other’s impacts. Overall, our study shows that direct effects were equivalent to, or more important than, indirect effects. We also demonstrate that the effects stemming from individual relationships can sum to produce net patterns that are negligible in magnitude. Further work on direct and indirect effects with observational data are needed to examine their magnitudes in natural communities.

Population cycles are fundamentally linked with spatial synchrony, the prevailing paradigm being that populations with cyclic dynamics are easily synchronised. That is, population cycles help give rise to spatial synchrony. Here we demonstrate this process can work in reverse, with synchrony causing population cycles. We show that timescale-specific environmental effects, by synchronising local population dynamics on certain timescales only, cause major population cycles over large areas in white-tailed deer. An important aspect of the new mechanism is specificity of synchronising effects to certain timescales, which causes local dynamics to sum across space to a substantial cycle on those timescales. We also demonstrate, to our knowledge for the first time, that synchrony can be transmitted not only from environmental drivers to populations (deer), but also from there to human systems (deer-vehicle collisions). Because synchrony of drivers may be altered by climate change, changes to population cycles may arise via our mechanism.

Fluctuations in population abundances are often correlated through time across multiple locations, a phenomenon known as spatial synchrony. Spatial synchrony can exhibit complex spatial structures, termed ‘geographies of synchrony’, that can reveal mechanisms underlying population fluctuations. However, most studies have focused on spatial extents of 10s to 100s of kilometres, making it unclear how synchrony concepts and approaches should apply to dynamics at finer spatial scales. We used network analyses, multiple regression on similarity matrices, and wavelet coherence analyses to examine micro‐scale synchrony and geographies of synchrony, over distances up to 30 m, in a serpentine grassland plant community. We found that species' populations exhibited a geography of synchrony even over such short distances. Often, well‐synchronized populations were geographically separate, a spatial structure that was shaped mainly by gopher disturbance and dispersal limitation, and to a lesser extent by relationships with other plant species. Precipitation was a significant driver of site‐ and community‐wide temporal dynamics. Gopher disturbance appeared to drive synchrony on 2‐ to 6‐year timescales, and we detected coherent fluctuations among pairs of focal plant taxa. Synthesis. Micro‐geographies of synchrony are an intriguing phenomenon that may also help us better understand community dynamics. Additionally, the related geographies of synchrony and coherent temporal dynamics among some species pairs indicate that incorporating interspecific interactions can improve understanding of population spatial synchrony.

The interactions between top- and intermediate-level predators can have significant effects on community structure of food webs. The direct and indirect effects of top predators not only affect prey communities both negatively (e.g. predation) and positively (e.g. thinning effects), but can also impact intermediate-level predators (via intraguild predation [IGP]). These IGP interactions can have especially far-reaching implications when predators of increased ecological importance, such as keystone predators, are involved. Yet, the strength of these interactions are often context-dependent with relationships that are highly variable, and little is known about the factors that shape the outcomes. We conducted a mesocosm experiment to test for the potential IGP interactions among top (invertebrate) and intermediate (amphibian) predators and their effects on a diverse prey community. We used larval Boyeria vinosa (Fawn Darner), a rarely studied member of the family Aeshnidae, and Ambystoma opacum (Marbled Salamander), a known keystone predator in parts of its range, in a mesocosm study with an additive experimental design. Each mesocosm received an equal assemblage of five anuran prey species. Total prey survival was lowest when both predators were present, but A. opacum overwhelmingly reduced the survival of three prey species, lowering species diversity in all food webs when present. Species diversity was highest in the B. vinosa food web, with one prey species (Anaxyrus americanus) emerging smaller and sooner than from other food webs. We did not detect any interactions between predator species, indicating that B. vinosa may not be as voracious as other members of Aeshnidae. Our findings suggest that density mediated IGP interactions are non-existent among our focal species. Ultimately, we also demonstrate the importance of examining variability in keystone predators and how abundant, but less-known predator species affect community structure.

Variation in the timing of breeding (i.e., phenological variation) can affect species interactions and community structure, in part by shifting body size differences between species. Body size differences can be further altered by density-dependent competition, though synergistic effects of density and phenology on species interactions are rarely evaluated. We tested how field-realistic variation in phenology and density affected ringed salamander (Ambystoma annulatum) predation on spotted salamanders (Ambystoma maculatum), and whether these altered salamander dynamics resulted in trophic cascades. In outdoor mesocosms, we experimentally manipulated ringed salamander density (low/high) and breeding phenology (early/late) of both species. Ringed salamander body size at metamorphosis, development, and growth were reduced at higher densities, while delayed phenology increased hatchling size and larval development, but reduced relative growth rates. Survival of ringed salamanders was affected by the interactive effects of phenology and density. In contrast, spotted salamander growth, size at metamorphosis, and survival, as well as the biomass of lower trophic levels, were negatively affected primarily by ringed salamander density. In an additional mesocosm experiment, we isolated whether ringed salamanders could deplete shared resources prior to their interactions with spotted salamanders, but instead found direct interactions (e.g., predation) were the more likely mechanism by which ringed salamanders limited spotted salamanders. Overall, our results indicate the effects of phenological variability on fitness-related traits can be modified or superseded by differences in density dependence. Identifying such context dependencies will lead to greater insight into when phenological variation will likely alter species interactions.

Both abiotic and biotic factors influence population and community structure. However, the simultaneous assessment of the relative importance of both types of factors is rarely performed for multiple traits of a population, such as body size and abundance. Comparisons among different demographic rates are necessary for teasing apart the importance of species interactions and/or environmental conditions on both population and community structure. We tested whether biotic (e.g., larval competition) or abiotic factors influenced larval salamander density and body size in natural populations of two known salamander competitors, Ambystoma talpoideum and A. maculatum. Over six years, we surveyed 33 ponds where these species co-occur in western Kentucky, USA. We found that larval densities between species were positively correlated, and that habitat features had contrasting, species-specific effects. Larval sizes for each species showed negative intra- and interspecific relationships with larval densities of eac...

Understanding metapopulation dynamics requires knowledge about local population dynamics and movement in both space and time. Most genetic metapopulation studies use one or two study species across the same landscape to infer population dynamics; however, using multiple co‐occurring species allows for testing of hypotheses related to different life history strategies. We used genetic data to study dispersal, as measured by gene flow, in three ambystomatid salamanders (Ambystoma annulatum, A. maculatum, and A. opacum) and the Central Newt (Notophthalmus viridescens louisianensis) on the same landscape in Missouri, USA. While all four salamander species are forest dependent organisms that require fishless ponds to reproduce, they differ in breeding phenology and spatial distribution on the landscape. We use these differences in life history and distribution to address the following questions: (1) Are there species‐level differences in the observed patterns of genetic diversity and genetic structure? and (2) Is dispersal influenced by landscape resistance? We detected two genetic clusters in A. annulatum and A. opacum on our landscape; both species breed in the fall and larvae overwinter in ponds. In contrast, no structure was evident in A. maculatum and N. v. louisianensis, species that breed during the spring. Tests for isolation by distance were significant for the three ambystomatids but not for N. v. louisianensis. Landscape resistance also contributed to genetic differentiation for all four species. Our results suggest species‐level differences in dispersal ability and breeding phenology are driving observed patterns of genetic differentiation. From an evolutionary standpoint, the observed differences in dispersal distances and genetic structure between fall breeding and spring breeding species may be a result of the trade‐off between larval period length and size at metamorphosis which in turn may influence the long‐term viability of the metapopulation. Thus, it is important to consider life history differences among closely related and ecologically similar species when making management decisions.

Direct and indirect effects both influence population and community dynamics. The relative strengths of these pathways are often compared using experimental approaches, but their evaluation in situ has been less frequent. We examined how individual and aggregate impacts of direct and indirect effects of species densities, proxies for competition and predation pressure, and habitat variables influenced patterns of larval density and body size of ringed (Ambystoma annulatum) and spotted salamanders (A. maculatum). We surveyed 150 ponds in Missouri, USA, from 2012 to 2014 to measure the density and body size of each focal species, the density of co-occurring pond food web members, and select habitat features. We used structural equation modeling to quantify the relative importance of direct and indirect pathways on both body size and larval density. Overall, both responses were explained through a combination of direct and indirect effects. However, the magnitudes of direct effects were often greater than indirect effects. Some of the direct and indirect relationships with larval salamander size and density were also consistent with results from experimental studies. Finally, total direct and indirect effects were often weaker due to habitat and density variables negating each other's impacts. Overall, our study shows that direct effects were equivalent to, or more important than, indirect effects. We also demonstrate that the effects stemming from individual relationships can sum to produce net patterns that are negligible in magnitude. Further work on direct and indirect effects with observational data are needed to examine their magnitudes in natural communities.

Phenology is a key driver of population and community dynamics. Phenological metrics (e.g., first date that an event occurred) often simplify information from the full phenological distribution, which may undermine efforts to determine the importance of life history events. Data regarding full phenological distributions are especially needed as many species are shifting phenology with climatic change which can alter life-history patterns and species dynamics. We tested whether skewness, kurtosis or maximum duration of breeding phenology affected juvenile emigration phenology and survival in natural populations of ringed (Ambystoma annulatum) and spotted salamanders (A. maculatum) spanning a 7-year period at two study locations. We evaluated the relative importance of different phenological metrics in breeding phenology and larval density dependence on emigration phenology and survival. We found that variability in emigration phenology differed by species, with ringed salamanders having a shorter duration and distributions that were more often right-skewed and leptokurtic compared to spotted salamanders. Emigration phenology was not linked to any measure of variability in breeding phenology, indicating phenological variability operates independently across life stages and may be subject to stage-specific influences. Emigration duration and skewness were partially explained by larval density, which demonstrates how phenological distributions may change with species interactions. Further tests that use the full phenological distribution to link variability in timing of life history events to demographic traits such as survival are needed to determine if and how phenological shifts will impact species persistence.

This study was to examine the influences of manual acupuncture (MA) and electrical heat corresponding to reinforcing methods on nitric oxide (NO) release over the skin regions in humans. A device with collecting solution was taped to the skin surface along pericardium (PC) or lung (LU) meridian. Acupuncture needles were gently inserted into PC 4 with reinforcing stimulation (low force/rate) for 20 minutes in the MA group. LU11 on the finger was heated (43-44°C) by electrical heat for 20 minutes. Biocapture was consecutively conducted for two 20-minute intervals during and after each treatment. Total nitrite and nitrate (NOx-) in the collecting samples were quantified using chemiluminescence in blinded fashion. BaselineNOx-levels are higher and tended to be higher over PC and LU acupoints during the 1st biocapture.NOx-levels over PC regions were consistently increased by MA during both intervals.NOx-concentrations over LU acupoints were increased and tended to be increased by electrical heat in the 1st and 2nd biocapture. The results suggest that reinforcing MA and electrical heat induce NO released from the local skin regions with higher levels at acupoints, which improve local circulation and contribute to the beneficial effects of the therapies.

Ecological and evolutionary processes commonly result in morphological variation among larval amphibians. Variation in head shape plays a critical role in both food capture and predation risk in gape-limited salamanders, yet in situ studies of head shape variability are rare outside of cannibal morph assessments. We examined allometry differences in larval head width (HW) and snout–vent length (SVL) among three sympatric species of ambystomatid salamanders from 166 ponds in Missouri, USA: Ringed Salamander (Ambystoma annulatum), Marbled Salamander (A. opacum), and Spotted Salamander (A. maculatum). We also tested whether several abiotic and biotic factors would predict HW after accounting for SVL. We found that larval HW and SVL were strongly correlated for all species but that the strength of this relationship varied among species. For early-stage larvae, Marbled Salamanders showed isometric scaling relationships, whereas both Spotted Salamanders and Ringed Salamanders were allometric. For late-...

In size-structured populations of predators, the threat of cannibalism can influence behavior of prey that are attempting to avoid predation by larger conspecifics, including reducing their foraging rates. Such behavioral responses subsequently release basal prey of both cannibal and non-cannibal predators from predation risk. However, whether the non-consumptive effects of cannibalism on conspecific predators varies with basal heterospecific prey density is relatively unexplored. I conducted a laboratory study in plastic containers to test whether cannibalism risk influenced the functional response of dragonflies while foraging on three different densities of larval salamander prey. Dragonfly predators foraged with a Type II functional response, and when exposed to cannibalism cues, per capita feeding rates were lower at high prey densities. Salamander prey mortality rates declined with increasing prey densities, but the presence of cannibalism risk did not influence this pattern. Overall, this study shows that functional response curves of predators can vary in response to whether cannibalism risk is present in their environment across a small range of prey densities. Incorporating synergistic effects of multiple processes, such as non-consumptive risk factors and prey density, may help further elucidate the processes that structure both predator and prey population dynamics.

Comparisons of spatial and temporal variation in demographic rates are crucial to understanding population dynamics. Yet, even well-studied species are often lacking in comparisons of such variability in demographic data, making these contrasts imperative to conduct in population ecology research. We conducted a long-term monitoring study of Spotted Salamanders (Ambystoma maculatum) at five ponds in Missouri, USA. We sampled populations using drift fences, and monitored breeding immigration dates, adult population sizes, sex ratio, juvenile recruitment, metamorph sizes, and metamorph emigration dates. Generally, we found that our study populations exhibited characteristics similar to other populations across their distribution. We also found spatial and temporal variation among populations in nearly all demographic parameters, however, indicating that multipopulation and multiyear studies will likely improve our inferential abilities in understanding population dynamics. We observed an overall ...

Predation can have strong effects on the structure of pond-breeding amphibian communities. Many factors can influence the outcome of predator–prey interactions, including differences in densities, ...

A mobile testbed capable of real-time (10 Hz) standoff microwave imaging for concealed threat detection is presented. The system samples a scene with a 1m x 1m multistatic switched antenna array operating at 24–29 GHz. It constructs images on a cost-effective processor at video rate, through the use of Fast Fourier Transform (FFT) imaging. Design and operation of the testbed are discussed, and representative experimental images are presented.

Predator species and body size represent critical factors that have differential effects on prey populations, as well as overall community structure. However, investigations of how morphologically-similar predator species, simultaneous to variation in predator body size, influence lower trophic levels are infrequently performed. We tested whether predator species and body size influenced the functional response curve of three larval ambystomatid salamanders (Ringed Salamander, Ambystoma annulatum Cope, 1886; Spotted Salamander, Ambystoma maculatum (Shaw, 1802); Marbled Salamander, Ambystoma opacum (Gravenhorst, 1807)) while eating congeneric prey. We combined larval salamanders of varying body sizes with up to six prey densities within experimental microcosms. We tested for the shape of the functional response curve and obtained parameter estimates for attack rate and handling time for each predator size – species combination. We found variability among both species and size classes, with a combination of type I and type II functional response curves. Large size classes of predators had higher attack rates than smaller size classes, but equivalently-sized larvae of different species exhibited differences in attack rates and handling time. Our study shows that predation risk varies depending on the size structure and diversity of predators present in a food web, and that grouping predators by either species or size class may reduce the ability to predict changes in community structure resulting from such interactions.

Monitoring the inundation state (wet or dry) of wetlands is critical to understanding aquatic community structure but can be costly and labor-intensive. We tested the ability of temperature data from cost-effective iButton data loggers to reflect the inundation state of wetlands in central Missouri, based on our hypothesis that dry ponds would show greater daily temperature variance than ponds that remained inundated with water. We evaluated this method with two experiments in large outdoor mesocosms, and in existing natural wetlands in which we had deployed iButtons. True inundation state from pond visits was compared to predicted inundation state over different temperature variance thresholds expected to delineate wet or dry ponds. We confirmed that the daily temperature variances of dry iButtons were higher than that of iButtons under water, as expected, but that variance was influenced by factors such as canopy cover. We also describe an automated procedure that can be used to determine whether a pond was wet or dry with greater than 80 % accuracy. Using this approach, changes in inundation state, the number of days wet and dry, and the number of drying and filling events can be calculated. Several caveats are also provided that should be considered prior to using this method to maximize the accuracy in assessing inundation state.

We examined pond-breeding amphibian community composition at 210 ponds in Missouri between 2002 and 2012 using drift fence, dipnet, and funnel trap data. We encountered a total of 20 pond-breeding amphibian species in the combined surveys. We also examined whether the presence of American Bullfrogs, Lithobates catesbeianus, and fish influenced these patterns of diversity. Our results indicate the presence of American Bullfrogs, fish, and their interaction influenced the community composition of amphibians at these sites but in opposite patterns. American Bullfrogs often had a positive relationship with the total number of species, total caudate species, and total anuran species, whereas fish presence was negatively associated overall with species diversity, and the presence of both American Bullfrogs and fish was negatively associated with anuran species diversity. It is important to have baseline community species composition data from wide geographical ranges so spatiotemporal changes in community structure can be noted and assessed.

A fundamental goal of evolutionary ecology is to understand how asymmetric competition influences phenotype expression, yet few studies have quantified the relative effects of intra- and interspecific competition on phenotypes. We examined the effects of intra- and interspecific larval competition on both discrete and continuous phenotype expression of the facultatively paedomorphic mole salamander (Ambystoma talpoideum). We manipulated the density and frequency of larval A. talpoideum and a common competitor, the spotted salamander (A. maculatum), in experimental mesocosms within a response surface design. The production of discrete ontogenetic morphs (metamorphs, paedomorphs, and overwintering larvae) was affected more by intraspecific than interspecific competition, but the effect varied between morphs. Paedomorph and metamorph production were more strongly affected by intraspecific than interspecific competition, while the production of overwintering larvae was affected by each type of competition app...

Background Disparities of care among stroke survivors are well documented. Effective interventions to improve recurrent stroke preventative care in vulnerable populations are lacking. Methods and Results In a randomized controlled trial, we tested the efficacy of components of a chronic care model–based intervention versus usual care among 404 subjects having an ischemic stroke or transient ischemic attack within 90 days of enrollment and receiving care within the Los Angeles public healthcare system. Subjects had baseline systolic blood pressure (SBP) ≥120 mm Hg. The intervention included a nurse practitioner/physician assistant care manager, group clinics, self-management support, report cards, decision support, and ongoing care coordination. Outcomes were collected at 3, 8, and 12 months, analyzed as intention-to-treat, and used repeated-measures mixed-effects models. Change in SBP was the primary outcome. Low-density lipoprotein reduction, antithrombotic medication use, smoking cessation, and physical activity were secondary outcomes. Average age was 57 years; 18% were of black race; 69% were of Hispanic ethnicity. Mean baseline SBP was 150 mm Hg in both arms. SBP decreased to 17 mm Hg in the intervention arm and 14 mm Hg in the usual care arm; the between-arm difference was not significant (−3.6 mm Hg; 95% confidence interval, −9.2 to 2.2). Among secondary outcomes, the only significant difference was that persons in the intervention arm were more likely to lower their low-density lipoprotein Conclusions This intervention did not improve SBP control beyond that attained in usual care among vulnerable stroke survivors. A community-centered component could strengthen the intervention impact. Clinical Trial Registration URL: https://clinicaltrials.gov . Unique identifier: NCT00861081.

Assessment of the relative strengths of intra- and interspecific competition has increased in recent years and is critical to understanding the importance of competition. Yet, whether intra- and interspecific competition can have non-additive effects has rarely been tested. The resulting fitness consequences of such non-additive interactions are important to provide the context necessary to advance our understanding of competition theory. We compared the strength of additive and non-additive intra- and interspecific competition by manipulating densities of a pair of larval salamanders (Ambystoma talpoideum and A. maculatum) in experimental mesocosms within a response surface design. Intraspecific density had the strongest effect on the strength of competition for both species, and few observed comparisons indicated interspecific competition was an important factor in predicting body size, growth or larval period length of either species. Non-additive effects of intra- and interspecific competition influenced some response variables, including size and mass at metamorphosis in A. maculatum, but at a reduced strength compared to intraspecific effects alone. Intraspecific competition was thus the dominant biotic interaction, but non-additive effects also impact the outcome of competition in these species, validating the importance of testing for and incorporating non-additive density effects into competition models.

Predation is a key determinant of pond community structure, yet not all predators are equally effective and not all life stages of potential prey are similarly susceptible. Understanding the effects of native and introduced species is essential to informing management strategies, especially for endemic and species of conservation concern. We examined the effects of five common predators (three native: Central Newts [Notophthalmus viridescens louisianensis], aeshnid dragonfly naiads [Aeshnidae], and Southern Leopard Frog tadpoles [Lithobates sphenocephalus]; and two introduced: Fathead Minnows [Pimephales promelas] and Mosquitofish [Gambusia affinis]) on survival of eggs and recently hatched larvae of Ringed Salamanders (Ambystoma annulatum). We also examined the effect of supplemental food or cover availability on survival at each stage. Predators primarily showed a binary response to eggs, consuming all or none of them. Supplemental food did not influence whether eggs or larvae were consumed. ...

Phenology often determines the outcome of interspecific interactions, where early-arriving species often dominate interactions over those arriving later. The effects of phenology on species interactions are especially pronounced in aquatic systems, but the evidence is largely derived from experimental studies. We examined whether differences in breeding phenology between two pond-breeding salamanders (Ambystoma annulatum and A. maculatum) affected metamorph recruitment and demographic traits within natural populations, with the expectation that the fall-breeding A. annulatum would negatively affect the spring-breeding A. maculatum. We monitored populations of each species at five ponds over 4 years using drift fences. Metamorph abundance and survival of A. annulatum were affected by intra- and interspecific processes, whereas metamorph size and date of emigration were primarily influenced by intraspecific effects. Metamorph abundance, snout-vent length, date of emigration and survival for A. maculatum were all predicted by combinations of intra- and interspecific effects, but often showed negative relationships with A. annulatum metamorph traits and abundance. Size and date of metamorphosis were strongly correlated within each species, but in opposite patterns (negative for A. annulatum and positive for A. maculatum), suggesting that the two species use alternative strategies to enhance terrestrial survival and that these factors may influence their interactions. Our results match predictions from experimental studies that suggest recruitment is influenced by intra- and interspecific processes which are determined by phenological differences between species. Incorporating spatiotemporal variability when modeling population dynamics is necessary to understand the importance of phenology in species interactions, especially as shifts in phenology occur under climate change.

Understanding patterns of dispersal, gene flow, and population differentiation are critical to making informed management and conservation decisions. By assessing these processes in multiple sympatric species, we can increase the generality and applicability of management plans. In this study, we assess patterns of genetic differentiation and pop- ulation structure in two ecologically similar ambystomatid salamanders in Missouri, USA. Ambystoma annulatum (rin- ged salamander) and A. maculatum (spotted salamander) are both dependent upon forested habitats and fishless ponds for reproduction, but differ in their breeding phenology. In comparing these species, we assessed the support for five different processes that we hypothesized to affect genetic differentiation: (1) resistance of landscape features to move- ment, (2) distribution of breeding habitat, (3) dispersal pro- pensity, (4) dispersal ability, and (5) breeding habitat quality. Of these hypotheses, we found support for differences in dispersal ability and propensity. In both species, there was a strong pattern of isolation-by-distance. However, A. annula- tum exhibited greater overall differentiation (F 0 ¼ 0:31 ), had a greater rate of differentiation increase with distance, and were grouped into three spatially congruent genetic clusters. In contrast, A. maculatum consisted of a single population cluster and overall F 0 ST was 0.047. We estimated the mean genetic dispersal distance of A. annulatum and A. maculatum to be 1,693 m and 2,050 m, respectively. Our results under- score the importance of considering multiple species when developing management criteria to better account for differ- ences in dispersal ability.

Understanding community interactions, such as predator–prey dynamics, is vital for determining species viability. Outside of larger macroinvertebrate predators, such as crayfish and dragonfly larva...

Intraguild (IG) predator density can alter its effects on intraguild prey populations through several mechanisms, including density-dependent processes that affect IG predator traits such as size or growth that enhance or limit its predatory abilities. We examined whether intraspecific density-dependence altered IG predator traits, as well as the subsequent interspecific effects among its intraguild prey within a larval salamander guild. Four densities of ringed salamanders (Ambystoma annulatum), the IG predator, were combined with the presence/absence of spotted salamanders (A. maculatum), the IG prey, within experimental mesocosms. We modeled the effects of A. annulatum density on both conspecific and heterospecific responses that would be indicative of density-dependent competition and predation, respectively. We also modeled the reciprocal interspecific effects of A. maculatum on A. annulatum. We found that increasing intraspecific density negatively affected morphological traits but not survival of A. annulatum. No interspecific effects of A. maculatum on A. annulatum were observed. Alternatively, traits of A. maculatum showed nonlinear relationships with increasing A. annulatum density. Thinning effects of A. annulatum on A. maculatum were observed, as survival was positively and size negatively related for A. maculatum with IG predator density. The temporal overlap of the IG predator and prey also increased nonlinearly with IG predator density, intensifying the potential encounter rate of the two species. Overall, this study shows that density-dependent processes in IG predators can significantly affect traits of both themselves, as well as IG prey, which could ultimately change whether competition or predation occurs between the two groups.

Loss or alteration of natural wetland habitats is a near ubiquitous global phenomenon. In the US, legislation mandates that all lost wetland habitats be replaced; manmade wetland habitats rarely have the same structural form or ecological function as natural wetlands. In the eastern US, these manmade pond habitats often serve as water sources for wildlife, but many are also utilized by amphibians for reproduction. Understanding the features that maximize species’ abundance and diversity is critical to effective management. In this study, we surveyed for ambystomatid salamander larvae at 169 manmade ponds in a military training installation. Three species were present: Ambystoma maculatum, A. opacum and the regionally endemic A. annulatum. We estimated larval densities in each pond in relation to landscape- and pond-level covariates. Important factors relating to larval density were forest habitat surrounding each pond, canopy cover over a pond, the number of ponds within 300 m of the focal pond, presence of fish, slope of the pond basin, hydroperiod and amount of vegetation within the pond. Density estimates for each species were best predicted by different combinations of these factors, underscoring the need to provide a range of pond habitats to promote species diversity on the landscape. Our results indicate that manmade ponds are providing a valuable reproductive resource, but that future construction of ponds on the landscape will best serve the salamander and broader amphibian community if different combinations of hydroperiod and slope are utilized.

Predation risk is an important contributor to community structure that varies in response to abiotic and biotic factors. In aquatic habitats, predation risk is often linked to hydroperiod as the latter directly influences predator identity within these ecosystems. For pond-breeding salamanders, intraguild predation (IGP) and cannibalism are prevalent interactions in larval communities, but the frequency of each type of agonistic interaction, as well as changes in their pervasiveness along hydroperiod gradients are not well understood. Size-structured populations of aquatic life stages (paedomorphic adults and overwintered larvae) of mole salamanders (Ambystoma talpoideum) have the potential to be dominant IG predators and cannibals in permanent ponds because of large size advantages over successive cohorts, but the species exists as only a single larval cohort in temporary ponds with reduced predatory abilities on guild members. Thus, both the potential for and intensity of predation by this species is li...

Spatial synchrony, defined as correlated temporal fluctuations among populations, is a fundamental feature of population dynamics, but many aspects of synchrony remain poorly understood. Few studies have examined detailed geographical patterns of synchrony; instead most focus on how synchrony declines with increasing linear distance between locations, making the simplifying assumption that distance decay is isotropic. By synthesising and extending prior work, we show how geography of synchrony, a term which we use to refer to detailed spatial variation in patterns of synchrony, can be leveraged to understand ecological processes including identification of drivers of synchrony, a long-standing challenge. We focus on three main objectives: (1) showing conceptually and theoretically four mechanisms that can generate geographies of synchrony; (2) documenting complex and pronounced geographies of synchrony in two important study systems; and (3) demonstrating a variety of methods capable of revealing the geography of synchrony and, through it, underlying organism ecology. For example, we introduce a new type of network, the synchrony network, the structure of which provides ecological insight. By documenting the importance of geographies of synchrony, advancing conceptual frameworks, and demonstrating powerful methods, we aim to help elevate the geography of synchrony into a mainstream area of study and application.

A video-rate microwave imaging aperture for concealed threat detection can serve as a useful tool in securing crowded, high foot traffic environments. Realization of such a system presents two major technical challenges: 1) implementation of an electrically large antenna array for capture of a moving subject, and 2) fast image reconstruction on cost-effective computing hardware. This paper presents a hardware-efficient multistatic array design to address the former challenge, and a compatible fast imaging technique to address the latter. Prototype hardware which forms a partition of an imaging aperture is discussed. Using this hardware, it is shown that the proposed array design can be used to form high-fidelity 3D images, and that the presented image reconstruction technique can form an image of a human-sized domain in ≤0.1s with low cost computing hardware.

Background— Stroke is the leading cause of adult disability. Inpatient programs optimize secondary stroke prevention care at the time of hospital discharge, but such care may not be continued after hospital discharge. Methods— To improve the delivery of secondary stroke preventive services after hospital discharge, we have designed a chronic care model–based program called SUSTAIN (Systemic Use of STroke Averting INterventions). This care intervention includes group clinics, self-management support, report cards, decision support through care guides and protocols, and coordination of ongoing care. The first specific aim is to test, in a randomized, controlled trial, whether SUSTAIN improves blood pressure control among an analytic sample of 268 patients with a recent stroke or transient ischemic attack discharged from 4 Los Angeles County public hospitals. Secondary outcomes consist of control of other stroke risk factors, lifestyle habits, medication adherence, patient perceptions of care quality, functional status, and quality of life. A second specific aim is to conduct a cost analysis of SUSTAIN from the perspective of the Los Angeles County Department of Health Services by using direct costs of the intervention, cost equivalents of associated utilization of county system resources, and cost equivalents of the observed and predicted averted vascular events. Conclusions— If SUSTAIN is effective, we will have the expertise and findings to advocate for its continued support at Los Angeles County hospitals and to disseminate the SUSTAIN program to other settings serving indigent, minority populations. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00861081.

Objectives The aim of this study was to assess clinical safety and efficacy outcomes of renal denervation executed by an externally delivered, completely noninvasive focused therapeutic ultrasound device. Background Renal denervation has emerged as a potential treatment approach for resistant hypertension. Methods Sixty-nine subjects received renal denervation with externally delivered focused ultrasound via the Kona Medical Surround Sound System. This approach was investigated across 3 consecutive studies to optimize targeting, tracking, and dosing. In the third study, treatments were performed in a completely noninvasive way using duplex ultrasound image guidance to target the therapy. Short- and long-term safety and efficacy were evaluated through use of clinical assessments, magnetic resonance imaging scans prior to and 3 and 24 weeks after renal denervation, and, in cases in which a targeting catheter was used to facilitate targeting, fluoroscopic angiography with contrast. Results All patients tolerated renal denervation using externally delivered focused ultrasound. Office blood pressure (BP) decreased by 24.6 ± 27.6/9.0 ± 15.0 mm Hg (from baseline BP of 180.0 ± 18.5/97.7 ± 13.7 mm Hg) in 69 patients after 6 months and 23.8 ± 24.1/10.3 ± 13.1 mm Hg in 64 patients with complete 1-year follow-up. The response rate (BP decrease >10 mm Hg) was 75% after 6 months and 77% after 1 year. The most common adverse event was post-treatment back pain, which was reported in 32 of 69 patients and resolved within 72 h in most cases. No intervention-related adverse events involving motor or sensory deficits were reported. Renal function was not altered, and vascular safety was established by magnetic resonance imaging (all patients), fluoroscopic angiography (n = 48), and optical coherence tomography (n = 5). Conclusions Using externally delivered focused ultrasound and noninvasive duplex ultrasound, image-guided targeting was associated with substantial BP reduction without any major safety signals. Further randomized, sham-controlled trials will be needed to validate this unique approach.

Background: Effective interventions to improve stroke preventative care in vulnerable populations have not been reported. Methods: We tested the impact of a chronic care model-based intervention program among 407 subjects with a recent stroke or transient ischemic attack at four Los Angeles County public hospitals. All subjects had a baseline systolic blood pressure (SBP) of at least 120 mm Hg and were randomized after baseline assessment in a 1:1 ratio to usual care or intervention, stratified by hospital and by English/Spanish language. The care management intervention was led by bilingual nurse practitioners or physician assistants, and it consisted of group clinics, self-management support, report cards, decision support, and coordination of ongoing care. Intention-to-treat analyses were conducted using repeated-measures mixed-effects models. The primary outcome was change in SBP. Secondary outcomes were other measures of SBP, low-density lipoprotein (LDL), ACC/AHA 10-year cardiovascular risk, adherence to antihypertensive and to antithrombotic medications, and physical activity. Results: Mean age was 57 years, 60% were male, 18% were African-American race, and 69% were Hispanic ethnicity. 48% had not graduated from high school. Baseline SBP was 150 mm Hg in the usual care arm and 149 mm Hg in the intervention arm. 12 month data were obtained in 333 participants (82%). There were substantial declines in SBP in both the usual care and intervention arms (Table). However, there were no significant differences between the two arms in either improvement of SBP from baseline or other measures of stroke risk factor control. Subgroup analyses did not reveal a differential impact of the intervention by race/ethnicity. Conclusion: Our care management intervention did not improve stroke risk factor control beyond what was attained in usual care. Further analyses are ongoing, and those findings will be used to guide modification of the intervention for future testing.

Background: Invasive catheter based techniques for renal denervation have been extensively examined in treating patients with resistant hypertension, with mixed results and some periprocedural complications. New evidence suggested that not all renal nerves are in the range of invasive procedures limited to a distance 4 to 6 mm from the lumen. Aims: To evaluate the safety and efficacy of an entirely non-invasive approach to renal denervation using externally delivered focused ultrasound to the peri-renal artery tissue with real time Doppler-based image guidance. Methods and results: Twenty-seven patients with severe, treatment resistant hypertension, defined as persistent systolic blood pressure (BP) > 160 mmHg despite 3 or more antihypertensive medications, were treated non-invasively with the Kona Medical Surround Sound System™. Focused ultrasound energy was delivered to the renal arteries bilaterally and surrounding tissue using Doppler-based imaging and continuous tracking with automatic correction for kidney motion throughout treatment. Patients received conscious sedation during the treatment period. At this time, all patients have completed 24 weeks and 23 patients 52 weeks of follow up. Post-denervation, the mean changes from baseline BP (175/92 mmHg) were -16.8/-8.6 mmHg at 3 weeks, -23.2/-10.8 mmHg at 6 weeks, -29.7/-13.1 mmHg at 12 weeks, -21.6/-8.7 mmHg at 24 weeks and -25.6/-10.1 mmHg at 52 weeks . No serious device-related events have been reported to date. Forty-one percent of subjects (11/27) reported mild back pain immediately following the denervation treatment. The majority of cases (7/11) completely resolved within three days post treatment without any significant intervention and no case was associated with any motor, sensory deficits. Conclusions: This is the first study in humans using a non-invasive renal denervation system in severe resistant hypertension. Results showed clinically meaningful reductions from baseline in office BP through 52 weeks post-denervation. The procedure was well-tolerated with no serious adverse events. This technology should enable patients to benefit from renal denervation therapy without the invasive risks associated with catheter based techniques.

We present data on amphibian density, species richness, and diversity from a 7140-ha area consisting of 200 ponds in the Midwestern U.S. that represents most of the possible lentic aquatic breeding habitats common in this region. Our study includes all possible breeding sites with natural and anthropogenic disturbance processes that can be missing from studies where sampling intensity is low, sample area is small, or partial disturbance gradients are sampled. We tested whether pond area was a significant predictor of density, species richness, and diversity of amphibians and if values peaked at intermediate pond areas. We found that in all cases a quadratic model fit our data significantly better than a linear model. Because small ponds have a high probability of pond drying and large ponds have a high probability of fish colonization and accumulation of invertebrate predators, drying and predation may be two mechanisms driving the peak of density and diversity towards intermediate values of pond size. We also found that not all intermediate sized ponds produced many larvae; in fact, some had low amphibian density, richness, and diversity. Further analyses of the subset of ponds represented in the peak of the area distribution showed that fish, hydroperiod, invertebrate density, and canopy are additional factors that drive density, richness and diversity of ponds up or down, when extremely small or large ponds are eliminated. Our results indicate that fishless ponds at intermediate sizes are more diverse, produce more larvae, and have greater potential to recruit juveniles into adult populations of most species sampled. Further, hylid and chorus frogs are found predictably more often in ephemeral ponds whereas bullfrogs, green frogs, and cricket frogs are found most often in permanent ponds with fish. Our data increase understanding of what factors structure and maintain amphibian diversity across large landscapes.