bluuebunny/crossref_metadata_2025 huggingface dataset:
Coenomorphs as phytometers of biotopes
Authors: Nazarenko N. N.
Published: May 2016

The article describes the A.L. Belgard system of vascular plant species coenomorphs as indicators of biotopes by using standardized Y.P. Didukh phytometer scales for 12 environmental factors. The classification and ordination of coenomorphs in the phytometer space was performed by using algorithms of discriminant analysis. The analysis is based on 2,186 species of the vascular plant flora of Ukraine. The classification accuracy was around 80% and above, the least homogenous was the petrophyte coenomorph. The validity of identification of ruderal coenomorphs was proved as an indicator of biotopes with increased content of soil nitrogen. Analysis of the a posteriori probability of species attribution to a coenomorph supports the validity of distinguishing transitional coenomorphs. Their number is small and each group contains a small number of species. The principal factors of classifying species by coenomorph are (in descending order of significance): minimum soil moisture, minimum light (shade), impoverishment of salts in the soil solution, high porosity of soil and impoverishment of carbonates of calcium in the soil and maximum values for radiation balance. The analysis of the distribution of coenomorphs in the space of the square of Mahalanobis distances and the ordination in the discriminant functions axis has determined the ranking of coenomorph of biotope and coenotic substitution: soil moisture (first discriminant function), radiation balance and shade (second discriminant function), salt regime and soil aeration (third discriminant function). For the vegetation of Ukraine this ordination of coenomorphs corresponds to the zonal factors of the distribution of biotopes and their limiting factors and the factors determining A.L. Belgard’s typology of natural and artificial forests: soil moisture, salinity of the soil solution, light conditions. The coenomorph optima for the principal factors have been defined in phytometer scales. This allows coenomorphs to be used as biotope phytometers and provides a preliminary assessment of those species whose place in the scales has not yet been determined. Analysis of posterior probabilities enabled us to determine the transitional coenomorphs, which are typical for ecotones between zonal and intrazonal vegetational ecosystems of Ukraine.
MARCOS DE LIDERAZGO EN LAS EMPRESAS: BUCARAMANGA Y SU AREA METROPOLITANA // FRAMES OF LEADERSHIP INTO THE COMPANIES: THE CITY OF BUCARAMANGA (COLOMBIA) AND ITS SOUROUNDED AREA // MARCOS DA LIDERANÇA EM EMPRESAS: O CASO DA CIDADE DE BUCARAMANG
Authors: Contreras Orlando , Vesga Morales Adriana Carolina , Barbosa Calderón Alejandra
Published: May 2016

El presente trabajo constituye un estudio exploratorio para la identificación de los estilos de liderazgo predominantes en los dirigentes de las empresas del Área Metropolitana de Bucaramanga (en adelante AMB). Para tal fin, se aplicó un instrumento de evaluación basado en el modelo de los cuatro marcos del liderazgo y el subsecuente análisis estadístico de los resultados. Considerando lo anterior, se encuentra que los gerentes tienden frecuentemente hacia prácticas como la definición de objetivos, procedimientos, normas claras, dirección a través del análisis y el diseño de planes ampliamente aceptados; y en menor medida hacia prácticas como el estímulo a la competencia interna, la resolución de conflictos y la conformación de una base de poder.
Exploring the micro-mechanics of triaxial instability in granular materials
Authors: Lopera Perez J. C. , Kwok C. Y. , O'Sullivan C. , Huang X. , Hanley K. J.
Published: May 2016

The instability of granular materials due to water infiltration under fully drained conditions has been previously considered in experimental studies. While laboratory experiments can provide macro-scale insight into drained instability, the micro-mechanics under such conditions are yet to be explored. This study has employed the discrete-element method (DEM) to simulate constant shear drained (CSD) tests for an ideal soil. CSD tests were initiated from a range of packing densities and stress conditions. The DEM simulations were able to qualitatively replicate laboratory CSD tests. The choice of the loading control parameter was seen to play a central role in the macro-scale second-order work to identify an effective failure. All samples considered attained an onset of instability that coincided with fluctuations in the second-order work from a particle scale. The time of occurrence of the onset of instability was seen to depend on initial packing density and stress state. A change in the evolution of macro- and micro-mechanical quantities, showing either a sharp increase or decrease, was observed once the CSD conditions had been reached. Finally, conventional drained then constant volume (CDCV) tests were carried out where the appearance of instabilities and the evolution of macro and micro quantities were found to be different from those observed in CSD tests. The results presented in this study indicate that the constant shear drained loading conditions can result in more unfavourable situations than for the undrained loading condition.
CKD Progression and Mortality among Hispanics and Non-Hispanics
Authors: Fischer Michael J. , Hsu Jesse Y. , Lora Claudia M. , Ricardo Ana C. , Anderson Amanda H. , Bazzano Lydia , Cuevas Magdalena M. , Hsu Chi-yuan , Kusek John W. , Renteria Amada , Ojo Akinlolu O. , Raj Dominic S. , Rosas Sylvia E. , Pan Qiang , Yaffe Kristine , Go Alan S. , Lash James P. ,   the Chronic Renal Insufficiency Cohort (CRIC) Study Investigators
Published: May 2016

Although recommended approaches to CKD management are achieved less often in Hispanics than in non-Hispanics, whether long-term outcomes differ between these groups is unclear. In a prospective longitudinal analysis of participants enrolled into the Chronic Renal Insufficiency Cohort (CRIC) and Hispanic-CRIC Studies, we used Cox proportional hazards models to determine the association between race/ethnicity, CKD progression (50% eGFR loss or incident ESRD), incident ESRD, and all-cause mortality, and linear mixed-effects models to assess differences in eGFR slope. Among 3785 participants, 13% were Hispanic, 43% were non-Hispanic white (NHW), and 44% were non-Hispanic black (NHB). Over a median follow-up of 5.1 years for Hispanics and 6.8 years for non-Hispanics, 27.6% of all participants had CKD progression, 21.3% reached incident ESRD, and 18.3% died. Hispanics had significantly higher rates of CKD progression, incident ESRD, and mean annual decline in eGFR than did NHW (P<0.05) but not NHB. Hispanics had a mortality rate similar to that of NHW but lower than that of NHB (P<0.05). In adjusted analyses, the risk of CKD progression did not differ between Hispanics and NHW or NHB. However, among nondiabetic participants, compared with NHB, Hispanics had a lower risk of CKD progression (hazard ratio, 0.61; 95% confidence interval, 0.39 to 0.95) and incident ESRD (hazard ratio, 0.50; 95% confidence interval, 0.30 to 0.84). At higher levels of urine protein, Hispanics had a significantly lower risk of mortality than did non-Hispanics (P<0.05). Thus, important differences in CKD progression and mortality exist between Hispanics and non-Hispanics and may be affected by proteinuria and diabetes.
Exome Sequencing Discerns Syndromes in Patients from Consanguineous Families with Congenital Anomalies of the Kidneys and Urinary Tract
Authors: Vivante Asaf , Hwang Daw-Yang , Kohl Stefan , Chen Jing , Shril Shirlee , Schulz Julian , van der Ven Amelie , Daouk Ghaleb , Soliman Neveen A. , Kumar Aravind Selvin , Senguttuvan Prabha , Kehinde Elijah O. , Tasic Velibor , Hildebrandt Friedhelm
Published: May 2016

Congenital anomalies of the kidneys and urinary tract (CAKUT) are the leading cause of CKD in children, featuring a broad variety of malformations. A monogenic cause can be detected in around 12% of patients. However, the morphologic clinical phenotype of CAKUT frequently does not indicate specific genes to be examined. To determine the likelihood of detecting causative recessive mutations by whole-exome sequencing (WES), we analyzed individuals with CAKUT from 33 different consanguineous families. Using homozygosity mapping and WES, we identified the causative mutations in nine of the 33 families studied (27%). We detected recessive mutations in nine known disease–causing genes: ZBTB24, WFS1, HPSE2, ATRX, ASPH, AGXT, AQP2, CTNS, and PKHD1. Notably, when mutated, these genes cause multiorgan syndromes that may include CAKUT as a feature (syndromic CAKUT) or cause renal diseases that may manifest as phenocopies of CAKUT. None of the above monogenic disease–causing genes were suspected on clinical grounds before this study. Follow-up clinical characterization of those patients allowed us to revise and detect relevant new clinical features in a more appropriate pathogenetic context. Thus, applying WES to the diagnostic approach in CAKUT provides opportunities for an accurate and early etiology–based diagnosis and improved clinical management.
A SEXUALIDADE NO HORIZONTE DO DISCURSO PÓS-MODERNO
Authors: Lago Clenio , Tarouco Sabryna Joane Voos Bortoncello , Silva Junior Edinaldo Enoque da
Published: May 2016

No momento de crise dos referenciais em que as relações passam do âmbito da estabilidade (até que a morte os separe, para eternas enquanto durem), a serem fruídas, voláteis, sem muita estabilidade, que qualquer comportamento parece correto, importa compreender o processo constitutivo da sexualidade, no horizonte do discurso pós-moderno. Para tanto, utilizou-se de pesquisa bibliográfica e coleta dos dados por meio de entrevistas individuais estruturadas com base em socialização e debate do tema no momento da entrevista. Com a pesquisa pode-se concluir que a crise moderna dá origem a várias “desconstruções” e traz como continuidade desse processo a pós-modernidade, com suas crises e quebra de tabus, mostrando-nos o quanto as relações pós-modernas estão vazias, inseguras e fragmentadas, mas representa um momento, um enfoque histórico que não pode ser ignorado, à medida que coloca em cena o humano em seu devir contingencial. Contudo, constitui possibilidade de diálogo enquanto poder fazer emergir a diversidade, que se, apenas em si, por si e para si é temerária e egoística.
MASCULINIDADES HEGEMÔNICAS E DISSIDÊNCIAS: TENSÕES CURRICULARES EM COTIDIANOS DE ESCOLAS DA PERIFERIA
Authors: Caetano Marcio Rodrigo Vale , Silva Junior Paulo Melgaço da , Goulart Treyce Ellen Silva
Published: May 2016

As identidades (sexuais), em sua relação com o espaço escolar estão, a todo tempo, tensionando e sofrendo a interpelação dos currículos. Considerando esse cenário, a partir das contribuições das teorias de gênero e sexualidades e da metodologia de Observação Participante, esse artigo objetivou questionar os modos como as masculinidades hegemônicas de duas escolas públicas da região da Baixada Fluminense do Rio de Janeiro são performatizadas e interagem com as identidades sexuais dissidentes, a exemplo de gays, travestis e transexuais (GT). Com os dados que subsidiaram a análise, produzidos a partir de práticas docentes dos autores, buscou-se questionar os currículos com vistas a interrogá-los sobre os discursos que produziram modos de subjetivação e ensinaram formas heteronormativas, complementares e assimétricas de projeção das identidades sexuais fortemente atravessadas pelas expectativas em torno da(s) masculinidade(s) negra(s).
GÊNEROS NÃO-BINÁRIOS: IDENTIDADES, EXPRESSÕES E EDUCAÇÃO
Authors: Dos Reis Neilton , Pinho Raquel
Published: May 2016

Neste texto, apresentamos um ensaio teórico sobre a construção não-binária de gêneros, no qual destacamos o processo educativo como privilegiado para socialização de adolescentes, jovens e adultos, seja para manutenção, seja para (des)(re)construção de signos e significados que permeiam as identidades. Partimos da problematização das diferenças entre características naturais supostamente pré-discursivas e processo socioculturais para a compreensão de uma estruturação binária na concepção de gênero. Buscamos ainda debater a construção realizada no espaço escolar acerca dos saberes sobre corpos, identidades e socializações. Com isso, propomos uma ação questionadora dos posicionamentos que as escolas têm assumido, de forma a repensar os contornos nos quais a pluralidade identitária pode ser trabalhada.
Living shorelines can enhance the nursery role of threatened estuarine habitats
Authors: Gittman Rachel K. , Peterson Charles H. , Currin Carolyn A. , Joel Fodrie F. , Piehler Michael F. , Bruno John F.
Published: May 2016

Coastal ecosystems provide numerous services, such as nutrient cycling, climate change amelioration, and habitat provision for commercially valuable organisms. Ecosystem functions and processes are modified by human activities locally and globally, with degradation of coastal ecosystems by development and climate change occurring at unprecedented rates. The demand for coastal defense strategies against storms and sea‐level rise has increased with human population growth and development along coastlines worldwide, even while that population growth has reduced natural buffering of shorelines. Shoreline hardening, a common coastal defense strategy that includes the use of seawalls and bulkheads (vertical walls constructed of concrete, wood, vinyl, or steel), is resulting in a “coastal squeeze” on estuarine habitats. In contrast to hardening, living shorelines, which range from vegetation plantings to a combination of hard structures and plantings, can be deployed to restore or enhance multiple ecosystem services normally delivered by naturally vegetated shores. Although hundreds of living shoreline projects have been implemented in the United States alone, few studies have evaluated their effectiveness in sustaining or enhancing ecosystem services relative to naturally vegetated shorelines and hardened shorelines. We quantified the effectiveness of (1) sills with landward marsh (a type of living shoreline that combines marsh plantings with an offshore low‐profile breakwater), (2) natural salt marsh shorelines (control marshes), and (3) unvegetated bulkheaded shores in providing habitat for fish and crustaceans (nekton). Sills supported higher abundances and species diversity of fishes than unvegetated habitat adjacent to bulkheads, and even control marshes. Sills also supported higher cover of filter‐feeding bivalves (a food resource and refuge habitat for nekton) than bulkheads or control marshes. These ecosystem‐service enhancements were detected on shores with sills three or more years after construction, but not before. Sills provide added structure and may provide better refuges from predation and greater opportunity to use available food resources for nekton than unvegetated bulkheaded shores or control marshes. Our study shows that unlike shoreline hardening, living shorelines can enhance some ecosystem services provided by marshes, such as provision of nursery habitat.
Estimating wildlife disease dynamics in complex systems using an Approximate Bayesian Computation framework
Authors: Kosmala Margaret , Miller Philip , Ferreira Sam , Funston Paul , Keet Dewald , Packer Craig
Published: May 2016

Emerging infectious diseases of wildlife are of increasing concern to managers and conservation policy makers, but are often difficult to study and predict due to the complexity of host–disease systems and a paucity of empirical data. We demonstrate the use of an Approximate Bayesian Computation statistical framework to reconstruct the disease dynamics of bovine tuberculosis in Kruger National Park's lion population, despite limited empirical data on the disease's effects in lions. The modeling results suggest that, while a large proportion of the lion population will become infected with bovine tuberculosis, lions are a spillover host and long disease latency is common. In the absence of future aggravating factors, bovine tuberculosis is projected to cause a lion population decline of ~3% over the next 50 years, with the population stabilizing at this new equilibrium. The Approximate Bayesian Computation framework is a new tool for wildlife managers. It allows emerging infectious diseases to be modeled in complex systems by incorporating disparate knowledge about host demographics, behavior, and heterogeneous disease transmission, while allowing inference of unknown system parameters.
Precision of systematic and random sampling in clustered populations: habitat patches and aggregating organisms
Authors: McGarvey Richard , Burch Paul , Matthews Janet M.
Published: May 2016

Natural populations of plants and animals spatially cluster because (1) suitable habitat is patchy, and (2) within suitable habitat, individuals aggregate further into clusters of higher density. We compare the precision of random and systematic field sampling survey designs under these two processes of species clustering. Second, we evaluate the performance of 13 estimators for the variance of the sample mean from a systematic survey. Replicated simulated surveys, as counts from 100 transects, allocated either randomly or systematically within the study region, were used to estimate population density in six spatial point populations including habitat patches and Matérn circular clustered aggregations of organisms, together and in combination. The standard one‐start aligned systematic survey design, a uniform 10 × 10 grid of transects, was much more precise. Variances of the 10 000 replicated systematic survey mean densities were one‐third to one‐fifth of those from randomly allocated transects, implying transect sample sizes giving equivalent precision by random survey would need to be three to five times larger. Organisms being restricted to patches of habitat was alone sufficient to yield this precision advantage for the systematic design. But this improved precision for systematic sampling in clustered populations is underestimated by standard variance estimators used to compute confidence intervals. True variance for the survey sample mean was computed from the variance of 10 000 simulated survey mean estimates. Testing 10 published and three newly proposed variance estimators, the two variance estimators (v) that corrected for inter‐transect correlation (v8andvW) were the most accurate and also the most precise in clustered populations. These greatly outperformed the two “post‐stratification” variance estimators (v2andv3) that are now more commonly applied in systematic surveys. Similar variance estimator performance rankings were found with a second differently generated set of spatial point populations,v8andvWagain being the best performers in the longer‐range autocorrelated populations. However, no systematic variance estimators tested were free from bias. On balance, systematic designs bring more narrow confidence intervals in clustered populations, while random designs permit unbiased estimates of (often wider) confidence interval. The search continues for better estimators of sampling variance for the systematic survey mean.
Acceleration and novelty: community restoration speeds recovery and transforms species composition in Andean cloud forest
Authors: Wilson Sarah Jane , Rhemtulla Jeanine M.
Published: May 2016

Community‐based tropical forest restoration projects, often promoted as a win‐win solution for local communities and the environment, have increased dramatically in number in the past decade. Many such projects are underway in Andean cloud forests, which, given their extremely high biodiversity and history of extensive clearing, are understudied. This study investigates the efficacy of community‐based tree‐planting projects to accelerate cloud forest recovery, as compared to unassisted natural regeneration. This study takes place in northwest Andean Ecuador, where the majority of the original, highly diverse cloud forests have been cleared, in five communities that initiated tree‐planting projects to restore forests in 2003. In 2011, we identified tree species along transects in planted forests (n = 5), naturally regenerating forests (n = 5), and primary forests (n = 5). We also surveyed 120 households about their restoration methods, tree preferences, and forest uses. We found that tree diversity was higher in planted than in unplanted secondary forest, but both were less diverse than primary forests. Ordination analysis showed that all three forests had distinct species compositions, although planted forests shared more species with primary forests than did unplanted forests. Planted forests also contained more animal‐dispersed species in both the planted canopy and in the unplanted, regenerating understory than unplanted forests, and contained the highest proportion of species with use value for local people. While restoring forest increased biodiversity and accelerated forest recovery, restored forests may also represent novel ecosystems that are distinct from the region's previous ecosystems and, given their usefulness to people, are likely to be more common in the future.
Determining the causes behind the collapse of a small pelagic fishery using Bayesian population modeling
Authors: Taboada Fernando G. , Anadón Ricardo
Published: May 2016

Small pelagic fish species present complex dynamics that challenge population biologists and prevent effective management. Huge fluctuations in abundance have traditionally been associated with external environmental forcing on recruitment, exempting other processes from contributing to fisheries collapse. On the other hand, theory predicts that density dependence and overexploitation can increase the likelihood of population oscillations. Here, we combined nonlinear population modeling with Bayesian analysis to examine the importance of different regulatory mechanisms on the collapse of European anchovy (Engraulis encrasicolus) in the Bay of Biscay. The approach relied on detailed population data and in a careful characterization of changes in the environment experienced by anchovy early stages based mainly on satellite remote sensing. Alternative hypotheses about external forcing on recruitment determined prediction skill and provided alternative interpretations of the causes behind the collapse. Density dependence was weak and unable to generate huge oscillations. Instead, models considering changes in phytoplankton phenology or in larval drift presented the best prediction skill. Nevertheless, an extensive surrogate analysis showed that environmental fluctuations alone barely explain anchovy collapse without considering the impact of fishing. Our results highlight the effectiveness of a Bayesian approach to analyze the dynamics and collapse of managed populations.
A characterization of autumn nocturnal migration detected by weather surveillance radars in the northeasternUSA
Authors: Farnsworth Andrew , Van Doren Benjamin M. , Hochachka Wesley M. , Sheldon Daniel , Winner Kevin , Irvine Jed , Geevarghese Jeffrey , Kelling Steve
Published: May 2016

Billions of birds migrate at night over North America each year. However, few studies have described the phenology of these movements, such as magnitudes, directions, and speeds, for more than one migration season and at regional scales. In this study, we characterize density, direction, and speed of nocturnally migrating birds using data from 13 weather surveillance radars in the autumns of 2010 and 2011 in the northeasternUSA. After screening radar data to remove precipitation, we applied a recently developed algorithm for characterizing velocity profiles with previously developed methods to document bird migration. Many hourly radar scans contained windborne “contamination,” and these scans also exhibited generally low overall reflectivities. Hourly scans dominated by birds showed nightly and seasonal patterns that differed markedly from those of low reflectivity scans. Bird migration occurred during many nights, but a smaller number of nights with large movements of birds defined regional nocturnal migration. Densities varied by date, time, and location but peaked in the second and third deciles of night during the autumn period when the most birds were migrating. Migration track (the direction to which birds moved) shifted within nights from south‐southwesterly to southwesterly during the seasonal migration peaks; this shift was not consistent with a similar shift in wind direction. Migration speeds varied within nights, although not closely with wind speed. Airspeeds increased during the night; groundspeeds were highest between the second and third deciles of night, when the greatest density of birds was migrating. Airspeeds and groundspeeds increased during the fall season, although groundspeeds fluctuated considerably with prevailing winds. Significant positive correlations characterized relationships among bird densities at southern coastal radar stations and northern inland radar stations. The quantitative descriptions of broadscale nocturnal migration patterns presented here will be essential for biological and conservation applications. These descriptions help to define migration phenology in time and space, fill knowledge gaps in avian annual cycles, and are useful for monitoring long‐term population trends of migrants. Furthermore, these descriptions will aid in assessing potential risks to migrants, particularly from structures with which birds collide and artificial lighting that disorients migrants.
Sperm whales reduce foraging effort during exposure to 1–2 kHz sonar and killer whale sounds
Authors: Isojunno Saana , Curé Charlotte , Kvadsheim Petter Helgevold , Lam Frans‐Peter Alexander , Tyack Peter Lloyd , Wensveen Paul Jacobus , Miller Patrick James O'Malley
Published: May 2016

The time and energetic costs of behavioral responses to incidental and experimental sonar exposures, as well as control stimuli, were quantified using hidden state analysis of time series of acoustic and movement data recorded by tags (DTAG) attached to 12 sperm whales (Physeter macrocephalus) using suction cups. Behavioral state transition modeling showed that tagged whales switched to a non‐foraging, non‐resting state during both experimental transmissions of low‐frequency active sonar from an approaching vessel (LFAS; 1–2 kHz, source level 214 dB re 1 μPa m, four tag records) and playbacks of potential predator (killer whale, Orcinus orca) sounds broadcast at naturally occurring sound levels as a positive control from a drifting boat (five tag records). Time spent in foraging states and the probability of prey capture attempts were reduced during these two types of exposures with little change in overall locomotion activity, suggesting an effect on energy intake with no immediate compensation. Whales switched to the active non‐foraging state over received sound pressure levels of 131–165 dB re 1 μPa during LFAS exposure. In contrast, no changes in foraging behavior were detected in response to experimental negative controls (no‐sonar ship approach or noise control playback) or to experimental medium‐frequency active sonar exposures (MFAS; 6–7 kHz, source level 199 re 1 μPa m, received sound pressure level [SPL] = 73–158 dB re 1 μPa). Similarly, there was no reduction in foraging effort for three whales exposed to incidental, unidentified 4.7–5.1 kHz sonar signals received at lower levels (SPL = 89–133 dB re 1 μPa). These results demonstrate that similar to predation risk, exposure to sonar can affect functional behaviors, and indicate that increased perception of risk with higher source level or lower frequency may modulate how sperm whales respond to anthropogenic sound.
Gene–environment interactions influence feeding and anti‐predator behavior in wild and transgenic coho salmon
Authors: Sundström L. F. , Lõhmus M. , Devlin R. H.
Published: May 2016

Environmental conditions are known to affect phenotypic development in many organisms, making the characteristics of an animal reared under one set of conditions not always representative of animals reared under a different set of conditions. Previous results show that such plasticity can also affect the phenotypes and ecological interactions of different genotypes, including animals anthropogenically generated by genetic modification. To understand how plastic development can affect behavior in animals of different genotypes, we examined the feeding and risk‐taking behavior in growth‐enhanced transgenic coho salmon (with two‐ to threefold enhanced daily growth rates compared to wild type) under a range of conditions. When compared to wild‐type siblings, we found clear effects of the rearing environment on feeding and risk‐taking in transgenic animals and noted that in some cases, this environmental effect was stronger than the effects of the genetic modification. Generally, transgenic fish, regardless of rearing conditions, behaved similar to wild‐type fish reared under natural‐like conditions. Instead, the more unusual phenotype was associated with wild‐type fish reared under hatchery conditions, which possessed an extreme risk averse phenotype compared to the same strain reared in naturalized conditions. Thus, the relative performance of genotypes from one environment (e.g., laboratory) may not always accurately reflect ecological interactions as would occur in a different environment (e.g., nature). Further, when assessing risks of genetically modified organisms, it is important to understand how the environment affects phenotypic development, which in turn may variably influence consequences to ecosystem components across different conditions found in the complexity of nature.
Multiyear drought‐induced morbidity preceding tree death in southeastern U.S. forests
Authors: Berdanier Aaron B. , Clark James S.
Published: May 2016

Recent forest diebacks, combined with threats of future drought, focus attention on the extent to which tree death is caused by catastrophic events as opposed to chronic declines in health that accumulate over years. While recent attention has focused on large‐scale diebacks, there is concern that increasing drought stress and chronic morbidity may have pervasive impacts on forest composition in many regions. Here we use long‐term, whole‐stand inventory data from southeastern U.S. forests to show that trees exposed to drought experience multiyear declines in growth prior to mortality. Following a severe, multiyear drought, 72% of trees that did not recover their pre‐drought growth rates died within 10 yr. This pattern was mediated by local moisture availability. As an index of morbidity prior to death, we calculated the difference in cumulative growth after drought relative to surviving conspecifics. The strength of drought‐induced morbidity varied among species and was correlated with drought tolerance. These findings support the ability of trees to avoid death during drought events but indicate shifts that could occur over decades. Tree mortality following drought is predictable in these ecosystems based on growth declines, highlighting an opportunity to address multiyear drought‐induced morbidity in models, experiments, and management decisions.
The adaptive capacity of lake food webs: from individuals to ecosystems
Authors: McMeans Bailey C. , McCann Kevin S. , Tunney Tyler D. , Fisk Aaron T. , Muir Andrew M. , Lester Nigel , Shuter Brian , Rooney Neil
Published: May 2016

Aquatic ecosystems support size structured food webs, wherein predator‐prey body sizes span orders of magnitude. As such, these food webs are replete with extremely generalized feeding strategies, especially among the larger bodied, higher trophic position taxa. The movement scale of aquatic organisms also generally increases with body size and trophic position. Together, these body size, mobility, and foraging relationships suggest that organisms lower in the food web generate relatively distinct energetic pathways by feeding over smaller spatial areas. Concurrently, the potential capacity for generalist foraging and spatial coupling of these pathways often increases, on average, moving up the food web toward higher trophic levels. We argue that these attributes make for a food web architecture that is inherently ‘adaptive’ in its response to environmental conditions. This is because variation in lower trophic level dynamics is dampened by the capacity of predators to flexibly alter their foraging behavior. We argue that empirical, theoretical, and applied research needs to embrace this inherently adaptive architecture if we are to understand the relationship between structure and function in the face of ongoing environmental change. Toward this goal, we discuss empirical patterns in the structure of lake food webs to suggest that ecosystems change consistently, from individual traits to the structure of whole food webs, under changing environmental conditions. We then explore an empirical example to reveal that explicitly unfolding the mechanisms that drive these adaptive responses offers insight into how human‐driven impacts, such as climate change, invasive species, and fisheries harvest, ought to influence ecosystem structure and function (e.g., stability, secondary productivity, maintenance of major energy pathways). We end by arguing that such a directed food web research program promises a powerful across‐scale framework for more effective ecosystem monitoring and management.
Fishery consequences of marine reserves: short‐term pain for longer‐term gain
Authors: Hopf Jess K. , Jones Geoffrey P. , Williamson David H. , Connolly Sean R.
Published: May 2016

Marine reserves are often established in areas that support fisheries. Larval export from reserves is argued to help compensate for the loss of fishable habitat; however, previous modeling studies have focused on long‐term equilibrium outcomes. We examined the transient consequences of reserve establishment for fished metapopulations, considering both a well‐mixed larval pool and a spatially explicit model based on a coral trout (Plectropomus spp.) metapopulation. When fishing pressure was reallocated relative to the area protected, yields decreased initially, then recovered, and ultimately exceeded pre‐reserve levels. However, recovery time was on the order of several years to decades. If fishing pressure intensified to maintain pre‐reserve yields, reserves were sometimes unable to support the increased mortality and the metapopulation collapsed. This was more likely when reserves were small, or located peripherally within the metapopulation. Overall, reserves can achieve positive conservation and fishery benefits, but fisheries management complementary to reserve implementation is essential.
Assessing cumulative impacts of forest development on the distribution of furbearers using expert‐based habitat modeling
Authors: Bridger M. C. , Johnson C. J. , Gillingham M. P.
Published: May 2016

Cumulative impacts of anthropogenic landscape change must be considered when managing and conserving wildlife habitat. Across the central‐interior of British Columbia, Canada, industrial activities are altering the habitat of furbearer species. This region has witnessed unprecedented levels of anthropogenic landscape change following rapid development in a number of resource sectors, particularly forestry. Our objective was to create expert‐based habitat models for three furbearer species: fisher (Pekania pennanti), Canada lynx (Lynx canadensis), and American marten (Martes americana) and quantify habitat change for those species. We recruited 10 biologist and 10 trapper experts and then used the analytical hierarchy process to elicit expert knowledge of habitat variables important to each species. We applied the models to reference landscapes (i.e., registered traplines) in two distinct study areas and then quantified the change in habitat availability from 1990 to 2013. There was strong agreement between expert groups in the choice of habitat variables and associated scores. Where anthropogenic impacts had increased considerably over the study period, the habitat models showed substantial declines in habitat availability for each focal species (78% decline in optimal fisher habitat, 83% decline in optimal lynx habitat, and 79% decline in optimal marten habitat). For those traplines with relatively little forest harvesting, the habitat models showed no substantial change in the availability of habitat over time. The results suggest that habitat for these three furbearer species declined significantly as a result of the cumulative impacts of forest harvesting. Results of this study illustrate the utility of expert knowledge for understanding large‐scale patterns of habitat change over long time periods.
Influences of prior wildfires on vegetation response to subsequent fire in a reburned Southwestern landscape
Authors: Coop Jonathan D. , Parks Sean A. , McClernan Sarah R. , Holsinger Lisa M.
Published: May 2016

Large and severe wildfires have raised concerns about the future of forested landscapes in the southwestern United States, especially under repeated burning. In 2011, under extreme weather and drought conditions, the Las Conchas fire burned over several previous burns as well as forests not recently exposed to fire. Our purpose was to examine the influences of prior wildfires on plant community composition and structure, subsequent burn severity, and vegetation response. To assess these relationships, we used satellite‐derived measures of burn severity and a nonmetric multidimensional scaling of pre‐ and post‐ Las Conchas field samples. Earlier burns were associated with shifts from forested sites to open savannas and meadows, oak scrub, and ruderal communities. These non‐forested vegetation types exhibited both resistance to subsequent fire, measured by reduced burn severity, and resilience to reburning, measured by vegetation recovery relative to forests not exposed to recent prior fire. Previous shifts toward non‐forested states were strongly reinforced by reburning. Ongoing losses of forests and their ecological values confirm the need for restoration interventions. However, given future wildfire and climate projections, there may also be opportunities presented by transformations toward fire‐resistant and resilient vegetation types within portions of the landscape.
Fire severity unaffected by spruce beetle outbreak in spruce‐fir forests in southwestern Colorado
Authors: Andrus Robert A. , Veblen Thomas T. , Harvey Brian J. , Hart Sarah J.
Published: May 2016

Recent large and severe outbreaks of native bark beetles have raised concern among the general public and land managers about potential for amplified fire activity in western North America. To date, the majority of studies examining bark beetle outbreaks and subsequent fire severity in the U.S. Rocky Mountains have focused on outbreaks of mountain pine beetle (MPB;Dendroctonus ponderosae) in lodgepole pine (Pinus contorta) forests, but few studies, particularly field studies, have addressed the effects of the severity of spruce beetle (Dendroctonus rufipennisKirby) infestation on subsequent fire severity in subalpine Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) forests. In Colorado, the annual area infested by spruce beetle outbreaks is rapidly rising, whileMPBoutbreaks are subsiding; therefore understanding this relationship is of growing importance. We collected extensive field data in subalpine forests in the eastern San Juan Mountains, southwestern Colorado, USA, to investigate whether a gray‐stage (<5 yr from outbreak to time of fire) spruce beetle infestation affected fire severity. Contrary to the expectation that bark beetle infestation alters subsequent fire severity, correlation and multivariate generalized linear regression analysis revealed no influence of pre‐fire spruce beetle severity on nearly all field or remotely sensed measurements of fire severity. Findings were consistent across moderate and extreme burning conditions. In comparison to severity of the pre‐fire beetle outbreak, we found that topography, pre‐outbreak basal area, and weather conditions exerted a stronger effect on fire severity. Our finding that beetle infestation did not alter fire severity is consistent with previous retrospective studies examining fire activity following other bark beetle outbreaks and reiterates the overriding influence of climate that creates conditions conducive to large, high‐severity fires in the subalpine zone of Colorado. Both bark beetle outbreaks and wildfires have increased autonomously due to recent climate variability, but this study does not support the expectation that post‐beetle outbreak forests will alter fire severity, a result that has important implications for management and policy decisions.
Long‐Term Corn Yield Impacted by Cropping Rotations and Bio‐Covers under No‐Tillage
Authors: Ashworth Amanda J. , Allen Fred L. , Saxton Arnold M. , Tyler Donald D.
Published: May 2016

Cropping diversity and bio‐covers are perceived as integral components of conservation tillage because of increased pest control and soil organic matter. Consequently, effects of cropping sequences and bio‐covers on corn (Zea mays L.) yields were assessed. Main effects were 10 cropping sequences of corn, cotton (Gossypium hirsutum L.), and soybean (Glycine max L.) on a Loring silt loam (fine‐silty, mixed, thermic Oxyaquic Fragiudalf) at the Research and Education Center (REC) at Milan, and seven cropping sequences of corn and soybean at the Middle Tennessee REC on a Maury silt loam (fine, mixed, active, mesic Typic Paleudalf). Sequences were repeated in 4‐yr cycles (i.e., Phases I, II, and III) from 2002 to 2013. Strip‐plot bio‐covers consisted of hairy vetch (Vicia villosa L.), Austrian winter pea (Pisum sativum L. sativum var. arvense), wheat (Triticum aestivum L.), poultry litter, and fallow control. Across 12‐ yr, bio‐covers, and locations, continuous corn and yields from all rotations were equivalent (7.6 and 7.9 Mg ha−1, respectively; P = 0.07). However, among phase × sequence interactions, corn–soybean–corn–soybean rotation was highest yielding during Phase III (10.1 Mg ha−1), which was greater than continuous corn during all phases (P < 0.05). Bio‐covers, particularly poultry litter and hairy vetch, increased yields (across locations and years) when compared to wheat (P < 0.05). Incorporating soybean or cotton once within 4‐yr cropping cycles was equivalent to continuous corn (P > 0.05). However, including soybean and cotton twice increased yields by 6 and 7%, respectively (P < 0.05). Results suggest including two crops within a 4‐yr phase increases yields compared to continuous corn.

Core Ideas

Increasing cropping sequence diversity promotes greater yields when two species are included in a rotation compared to continuous corn.

Including soybean and cotton twice increased yields by 6 and 7%, respectively.

Bio‐covers, particularly poultry litter and hairy vetch, increased corn yields compared to wheat cover crops.
Total Phosphorus Concentration Trends in 40 Iowa Rivers, 1999 to 2013
Authors: Wang Chao , Chan Kung‐Sik , Schilling Keith E.
Published: May 2016

Excessive phosphorus (P) in rivers is prompting states to develop strategies to reduce P concentrations and export. The goal of this study was to assess the current condition by analyzing trends in total P (TP) concentrations at 40 river monitoring sites in Iowa for the period 1998 to 2013. We used monthly river monitoring data collected by the State of Iowa at ambient sites located beyond the influence of point sources or cities. Study objectives were to assess the presence of any linear trends in the TP concentration data using a time‐series method that accounted for temporal correlation in the data and discharge and to combine the trend information from individual sites into an assessment of the statewide rate of change in river TP concentrations. Results indicated that annual TP concentrations were significantly decreasing at 12 sites (p < 0.05), with concentrations ranging from 7.5% (Maple River) to 2.6% (Boyer River) and averaging 4.1% for the 12 sites. No statistically significant change was measured at 28 sites (p > 0.05), although all but four of these sites had decreasing concentrations. As a population of sampled rivers across Iowa, TP concentrations were declining at an annual rate of approximately 2.6%. The decreasing trends are consistent with reported reductions in sediment concentrations measured in the Raccoon River and with decreasing trends detected in other midwestern rivers. We attribute the decreasing TP trends primarily to improvements in conservation and land management. Although reducing nonpoint source TP concentrations in Iowa rivers will be a tremendous challenge for the agricultural community, progress is being made toward meeting this goal with existing programs.

Core Ideas

Phosphorus concentrations were assessed at 40 Iowa rivers.

Phosphorus concentrations were decreasing by 4.1% at 12 sites.

Across Iowa, P concentrations are declining annually by 2.6%.

Reductions are most likely attributable to conservation.
Development of a New Manure Amendment for Reducing Ammonia Volatilization and Phosphorus Runoff from Poultry Litter
Authors: Moore Philip A.
Published: May 2016

Treating poultry litter with alum is a best management practice that reduces phosphorus (P) runoff and ammonia (NH3) emissions. However, alum prices have increased substantially during the past decade. The goal of this research was to develop inexpensive manure amendments that are as effective as alum in reducing NH3volatilization and P runoff. Sixteen amendments were developed using mixtures of alum mud, bauxite ore, sulfuric acid, liquid alum, and water. Alum mud is the residual left over from alum manufacture when produced by reacting bauxite with sulfuric acid. A laboratory NH3volatilization study was conducted using 11 treatments: untreated poultry litter, poultry litter treated with liquid or dry alum, or eight new mixtures. All of the litter amendments tested resulted in significantly lower NH3volatilization than untreated litter. Dry and liquid alum reduced NH3losses by 86 and 75%, respectively. The eight new litter amendments reduced NH3losses from 62 to 73% compared with untreated litter, which was not significantly different from liquid alum; the three most effective mixtures were not significantly different from dry alum. Water‐extractable P (WEP) was significantly reduced by all of the amendments, three of which resulted in significantly lower WEP than dry alum. The most promising new amendments were mixtures of alum mud, bauxite, and sulfuric acid. The potential impact of these amendments could be enormous because they could be produced for less than half the price of alum while being as effective in reducing NH3emissions and P runoff.

Core Ideas

Alum additions to poultry litter reduce ammonia emissions and P runoff.

The price of alum has increased dramatically, creating a need for cheaper products.

New manure amendments were developed using alum mud (a byproduct), bauxite, and sulfuric acid.

Three of these new products reduced ammonia volatilization and WEP as well as alum.

These new amendments should be more cost‐effective than alum because they are cheaper to produce.