bluuebunny/crossref_metadata_2025_split huggingface dataset:
Defoliation and gender effects on fitness components in three congeneric and sympatric understorey palms
Authors: Hernández‐Barrios Juan C. , Anten Niels P. R. , Ackerly David D. , Martínez‐Ramos Miguel 
Published: May 2013

Summary
Rain forest understorey perennial plants can be frequently exposed to leaf area losses induced by herbivory or physical damage from falling canopy debris. In dioecious species, tolerance to defoliation may differ between genders (e.g. females may suffer more than males), but this topic has so far received little attention.
Here, we quantified gender‐dependent effects of increased levels (0–100%) of sustained defoliation (applied bi‐annually for 2 years) on vital rates in three economically important dioecious understorey palm species in the genus Chamaedorea (C. elegans, C. ernesti‐augustii and C. oblongata). We also quantified gender differences in functional and life‐history traits and assessed the direct reproductive costs in terms of biomass allocation to reproduction.
In the three species, non‐defoliated (control) females were smaller and had three to seven times higher reproductive allocation than males.
Defoliation did not affect survivorship in any of the three species, except in the 100% defoliation treatment. Stem growth (RGR) and especially reproduction (probability of reproduction and reproductive output) were negatively affected by defoliation. Females of C. ernesti‐augustii suffered higher mortality than males at 100% defoliation, but this was not the case for the other two species. Also, only in C. ernesti‐augustii females exhibited lower RGR than males. In all species, the probability of reproduction did not differ between genders. The reproductive output (production rate of inflorescences) differed among genders only in C. ernesti‐augustii, where males were more productive than females.
Interestingly, in most cases, defoliation effects on vital rates did not differ significantly between males and females, indicating that tolerance to defoliation was similar between genders. Such results were independent of plant size (stem length).
Synthesis. Our results do not support the prevailing theory that the greater reproductive costs of females will lead to reduced tolerance to stresses such as defoliation. The implications of these results and their importance for designing sustainable leaf harvesting regimes are discussed.
Extirpation‐resistant species do not always compensate for the decline in ecosystem processes associated with biodiversity loss
Authors: Davies Thomas W. , Jenkins Stuart R. , Kingham Rachel , Hawkins Stephen J. , Hiddink Jan G. 
Published: May 2013

Summary

Accelerating rates of biodiversity loss may result in a rapid decline in important ecosystem processes such as carbon capture. Whether extirpation‐resistant species compensate for the decline in ecosystem processes associated with the loss of extirpation‐prone species is poorly understood.

We apply a novel approach to answer this question using an assemblage of salt marsh plants. First, manipulations were performed to simulate a realistic sequence of species loss, based on observed sensitivity to disturbance. Then, changes in biomass and primary production of extirpation‐resistant species were monitored over three consecutive growing seasons.

Extirpation‐resistant species did not compensate for the loss of either biomass or primary production associated with the removal of extirpation‐prone species.

Factors that determine the potential for compensation within ecosystems are discussed. These include resource‐regulated compensation rates, the level of functional redundancy within an assemblage and the extirpation resistance of species which possess good compensation traits.

Synthesis. These results suggest that we cannot assume extirpation‐resistant species will compensate for the decline in ecosystem processes associated with biodiversity loss across all ecosystems. Understanding those factors that influence the ability of ecosystems to compensate for declines in ecosystem processes associated with biodiversity loss constitutes a significant challenge.
Predicting invasiveness and range size in wetland plants using biological traits: a multivariate experimental approach
Authors: Hovick Stephen M. , Peterson Chris J. , Carson Walter P. 
Published: May 2013

Summary

Predicting invasion potential across a wide range of plant species using only their biological traits is often challenging. We present a novel approach, aligning species along a multivariate axis of putative invasiveness traits. The traits were quantified in a common garden in which we manipulated two critical variables thought to strongly influence invasiveness: herbivory and resource availability.

We used principal component analysis (PCA) to characterize 20 species based on seven key traits (percentage germination, specific leaf area, seed mass, above‐ground biomass, below‐ground biomass, response to fertilization and response to herbivory). We then assessed whether the linear combination of traits identified by axis 1 of the PCA could predict invasiveness.

Axis 1 of the trait‐based PCA explained nearly 40% of variation in two literature‐based invasiveness scores; thus, we considered it to be useful as a trait‐based invasiveness index. Literature‐based invasiveness was greatest in large species (both above‐ground and below‐ground) with high percentage germination, small positive responses to fertilization and small negative responses to herbivory.

Contrary to expectations from the enemy release hypothesis, species that were native to our region and highly invasive elsewhere were associated with only weak responses to insect herbivory. This suggests that invasion potential may be highest in species that are insensitive to herbivore pressure, rather than species benefitting the most from enemy release.

Native range size is often an effective predictor of invasiveness, although the underlying mechanisms are unclear; we therefore compared the predictive ability of range size versus biological traits. Our trait‐based index was a better predictor of invasiveness than range size, while also explaining nearly 20% of the variation in longitudinal range size.

Synthesis. We present a novel method for using traits to quantify invasiveness that appears to have broad predictive utility. Our results explicitly link biological traits to range size and global invasiveness, perhaps reflecting a general ecological strategy in plants. Following additional testing, this simple method could be utilized in a pre‐introduction screening protocol, and we provide practical recommendations for doing so.
Species traits and plant performance: functional trade‐offs in a large set of species in a botanical garden
Authors: Herben Tomáš , Nováková Zuzana , Klimešová Jitka , Hrouda Lubomír 
Published: May 2013

Summary

Earlier research has established a number of relationships between community structure and plant traits. However, these relationships are mediated by demographic processes that are constrained, but not determined, by the trait values, and involve responses of plants to their environments. In particular, life‐history costs and associated trade‐offs need to be examined at the level of demographic processes such as plant survival and reproduction, not only at the level of individual trait values.

We examined these demographic trade‐offs using data on vegetative and seed reproduction from 951 species of the Central European flora kept in the Botanical Garden of Charles University in Prague. With each species grown under conditions close to its natural habitat, we view the data as information on vegetative and seed reproduction under favourable conditions. We used nonparametric tests and ordinal regressions to examine relationships of the vegetative and seed reproduction to each other, as well as to commonly used traits such as plant height, leaf size, specific leaf area, seed size and clonal traits.

There was an overall negative correlation between seed and vegetative reproduction, indicating trade‐off between these two modes of reproduction. In contrast, there was no evidence of a trade‐off between clonal and seed traits.

Traits of clonal growth were related to vegetative reproduction in the garden and seed trait to seed reproduction in the garden. Further, there were correlations between seed reproduction and clonal traits and vice versa. These results suggest that seed reproduction is associated with a wider array of traits than only seed traits, and vegetative reproduction with a wider array than clonal traits again indicating complex life‐history relationships. These relationships did not change substantially after the incorporation of phylogenetic information.

Synthesis. The results suggest that trade‐offs between vegetative and seed reproduction are not revealed by analysis of species traits, probably due to the fact that trade‐offs often only arise due to life‐history costs that are shaped by the local environment. This highlights the importance of examining life‐history processes associated with trait values.
A general modelling framework for resource‐ratio and CSR theories of plant community dynamics
Authors: Jabot Franck , Pottier Julien 
Published: May 2013

Summary

Grime's CSR and Tilman's resource‐ratio theories are two major contributions to our understanding of plant community dynamics. They have both been corroborated empirically, whilst providing several contradictory predictions. Notably, contrary to Tilman, Grime predicts that competition for soil resources is unimportant on poor soils.
We show that Grime's CSR theory can be modelled with the same type of differential equations for resource and plant biomass dynamics used by Tilman in his resource‐ratio theory.
Using this unified modelling framework, we demonstrate that both models predict intense competition for soil resources on poor soils, as long as biomass loss per unit mass is modelled as a size‐independent process. When considering biomass loss per unit mass as a size‐dependent process mimicking farming activities, both models predict a unimodal relationship between soil fertility and the intensity of soil resource competition, and a decreasing relationship between disturbance rate and resource competition.
Synthesis. Our modelling analysis reveals that the resource‐ratio and CSR theories make different predictions regarding competition on poor soils, not because of their differing schemes of plant strategies, but because of the different disturbance types that they are considering. Tilman's predictions apply to little disturbed natural habitats, whilst Grime's predictions apply to disturbed ones.
Seed size and provenance mediate the joint effects of disturbance and seed predation on community assembly
Authors: Maron John L. , Pearson Dean E. , Potter Teal , Ortega Yvette K. 
Published: May 2013

Summary

Local plant community assembly is influenced by a series of filters that affect the recruitment and establishment of species. These filters include regional factors that limit seeds of any given species from reaching a local site as well as local interactions such as post‐dispersal seed predation and disturbance, which dictate what species actually establish. How these filters interact to influence recruitment into local assemblages, and whether they act differentially on individual species based on traits such as seed size or their provenance (i.e. native vs. exotic), has not been well examined. Such studies, however, are crucial for understanding community assembly and for making predictions about what species might be favoured under specific ecological circumstances.

We added 20 native and 19 exotic species that varied in seed size to undisturbed or experimentally disturbed subplots in and out of larger rodent exclusion plots at ten grassland sites across the Blackfoot River drainage in western Montana, USA.

Individually, exclusion of rodent seed predators and disturbance substantially increased cumulative (summed across all species) seedling recruitment. Exclusion of rodent seed predators enhanced recruitment to a greater extent in disturbed rather than undisturbed plots and for native species compared with exotics, while disturbance enhanced recruitment to a greater extent for exotics compared with natives. Examination of individual species responses indicated that results were generalizable across species within each group and not driven by the response of a few species.

Seed size mediated these patterns. Notably, the positive effect of rodent exclusion on recruitment was greater for large‐ versus small‐seeded species, while the impact of disturbance on recruitment was more pronounced for small‐seeded exotics relative to other groups.

Synthesis. These results reveal that local ‘filters’ such as post‐dispersal seed predation and disturbance can individually and collectively impose strong limitation on seedling recruitment into local assemblages. Seed size importantly predicts how strongly individual species are influenced by these local filters. Interestingly, in situ community filters have differential effects on native versus exotic species, suggesting that processes that limit native recruitment may not have the same inhibitory influence on exotics.
Differential seedling establishment of woody plants along a tree density gradient in Neotropical savannas
Authors: Salazar Ana , Goldstein Guillermo , Franco Augusto C. , Miralles‐Wilhelm Fernando 
Published: May 2013

Summary

Seedling dynamics are crucial for understanding spatial plant distribution patterns, yet little is known about seedling establishment in Neotropical savannas because empirical studies at the community level are scarce.
Over 2 years, we studied the recruitment and survival of an initial seedling assemblage and three cohorts of recruits of woody plants within 216 plots of 1 m2 located along a tree density gradient in the savannas of central Brazil. These savannas differ in tree density and canopy cover, from closed (high canopy cover) to open savannas (low canopy cover), and are located along shallow topographic gradients.
We measured community‐wide seedling limitation (i.e. proportion of 1‐m2 plots without seedlings of any woody species), photosynthetic photon flux density, litter cover, soil moisture and soil nutrients in each savanna type. Because closed savannas had lower PPFD and higher leaf litter cover than open savannas, we evaluated the effects of light level and litter cover on seedling emergence of nine dominant savanna woody species under controlled conditions in a glasshouse.
Density, recruitment and survival of seedlings decreased over time because of mortality in all savanna types, but they were consistently higher in closed than in open savannas. Community‐wide seedling limitation was significantly lower in closed (0.16 ± 0.03) than in open (0.30 ± 0.05) savannas.
In the glasshouse, high litter cover and very low light levels reduced seedling emergence of most species, suggesting an adaptation to delay seed germination until the wet season when soil water availability is high and leaf litter rapidly decomposes.
Synthesis: In Neotropical savannas, tree canopy cover facilitates seedling establishment of woody species by reducing stressful environmental conditions. In particular, low irradiance and high litter cover in closed savannas enhance the recruitment and survival of woody seedlings relative to open savannas by reducing soil water deficits and increasing nutrient availability in the upper soil layers. The higher seedling limitation of tree species in open than in closed savannas contributes to maintain relatively different balances between trees and herbaceous plants along topographic gradients in Neotropical savannas and helps to explain spatial distribution patterns of woody species in these ecosystems.
Use of Plain Radiography in the Diagnosis, Surgical Management, and Postoperative Treatment of Obstructive Urolithiasis in 25 Goats and 2 Sheep
Authors: Kinsley Marc A. , Semevolos Stacy , Parker Jill E. , Duesterdieck‐Zellmer Katja , Huber Michael 
Published: May 2013

AbstractObjectiveTo describe use of plain radiography for diagnosis, surgical management, and postoperative treatment of obstructive urolithiasis in small ruminants.Study DesignRetrospective case series.AnimalsSmall ruminants (n = 27; 25 goats, 2 sheep).MethodsMedical records (January 2002–November 2011) and radiographs for all small ruminants diagnosed with obstructive urolithiasis and having plain abdominal radiographs were reviewed. Signalment, surgical procedures, radiographic findings, ultrasonographic findings, position of calculi, and how plain radiography influenced surgical management and postoperative treatment were recorded.ResultsRadiopaque urinary calculi were detected in 23 (85%) plain radiographic studies. Location of uroliths determined by plain radiography included: cystic only (n = 5), distal to the sigmoid flexure and cystic (5), subischial (5), distal to the sigmoid flexure only (3), sigmoid flexure (3), and subischial and cystic (2). In 8 of these animals, postoperative radiographs revealed residual calculi in the urethra and were essential for their targeted removal by urethrotomy in 7 animals.ConclusionsIn regions where radiopaque calculi (calcium carbonate, calcium oxalate, silica) are commonly encountered in small ruminants, plain radiographs are recommended to determine the appropriate surgical approach(es) and to confirm resolution of the obstruction.
Does policy name matter? The effect of framing on the evaluations of African American applicants
Authors: Awad Germine H. 
Published: May 2013

AbstractAffirmative action continues to be one of the most contentious policies in the U.S. The current study examined the effect of hiring policy framing on the evaluation of African American applicants. Participants (N = 204) reviewed the résumé of an African American man either hired under an affirmative‐action or a diversity‐initiative frame. Results indicated that the applicant was evaluated as more competent under the diversity‐initiative frame than the affirmative‐action frame. This was especially true for White and conservative raters. The findings suggest that shifting to an emphasis on diversity instead of affirmative action may decrease negative attitudes toward affirmative‐action beneficiaries.
Exploring the effect of in‐group and out‐group race‐related stressors on anxiety among Asian Pacific Islander American students
Authors: French Sabine Elizabeth , Tran Nellie , Chávez Noé Rubén 
Published: May 2013

AbstractThis cross‐sectional study examined (a) the impact of in‐group (own‐group conformity pressure) and out‐group (perceived discrimination, stereotype confirmation concern) race‐related stressors; (b) the direct effect of 2 in‐group‐ (private regard, centrality) and 1 out‐group‐oriented (public regard) racial identity factors; and (c) the potential protective role of these identity factors on the impact of stressors on the anxiety of Asian Pacific Islander American (API) college students attending a racially diverse university. As predicted, positive feelings toward one's own racial group (i.e., private regard) had a significant negative relationship with anxiety. Private regard protected APIs from own‐group conformity pressures and stereotype confirmation concerns. Findings address the diverse university context that may create acculturative pressures or stereotype confirmation concern conditions.
Sleep and prejudice: a resource recovery approach
Authors: Ghumman Sonia , Barnes Christopher M. 
Published: May 2013

AbstractDoes sleepiness make one more likely to engage in stereotyping? Are people more likely to be prejudiced because of a poor night of sleep? Borrowing from ego depletion theory and research on self‐control and prejudice, the present work investigates these questions. We suggest that sleep is a diminishable resource that fuels self‐control and is, therefore, necessary for inhibiting prejudice. A series of 3 studies show that sleep did influence prejudice. Furthermore, we found that the relationship between sleep and prejudice was marginally moderated by negative implicit associations, such that this relationship primarily held true for individuals who have high negative implicit associations. These results highlight the critical role that sleep plays in suppressing prejudice.
Inter‐Arm Blood Pressure Differences in Young, Healthy Patients
Authors: Grossman Alon , Prokupetz Alex , Gordon Barak , Morag‐Koren Nira , Grossman Ehud 
Published: May 2013

The prevalence and magnitude of inter‐arm BP difference (IAD)in young healthy patients is not well characterized. Flight academy applicants and designated aviators undergo annual evaluation that includes blood pressure (BP)measurement on both arms. AllBPmeasurements performed from January 1, 2012, to April 30, 2012, were recorded andIADwas calculated. Results were compared between patients in whomBPwas initially measured in the right arm (group 1), those in whomBPwas initially measured in the left arm (group 2), and those in whom the arm in whichBPwas initially measured was not recorded (group 3). A total of 877 healthy patients hadBPmeasured during the study period. In the entire group, mean systolicBPwas the same in both arms. AbsoluteIADwas 5.6±5.5 mm Hg for systolic and 4.7±4.5 mm Hg for diastolicBP.IAD>10 mm Hg was recorded in 111 (12.6%) and 77 (8.8%) patients for systolic and diastolicBP,respectively.IADwas the same in the 3 groups and was unrelated to age, body mass index, and heart rate, but was related to systolicBP.IADis common in young healthy patients, is not dependent on which arm was measured first, and unrelated to age, body mass index, and heart rate.
Estimation of vitamin D levels in patients with pemphigus vulgaris
Authors: EL‐Komy M.H.M. , Samir N. , Shaker O.G. 
Published: May 2013

AbstractBackgroundKeratinocyte acantholysis as a result of pathogenic Dsg3‐antibodies production by B cells leads to Pemphigus vulgaris (PV). Vitamin D, through its participation in several immune modulatory functions including B cells apoptosis, Th2 cell differentiation, apoptotic enzyme regulation and Tregs functions, may be actively involved in the immune regulation of PV.ObjectiveTo evaluate Vitamin D status in PV patients in comparison to controls in an attempt to determine its role in this autoimmune disease.MethodsUsing ELISA technique, 25‐hydroxyvitamin D (25OHD) was determined for 34 pemphigus vulgaris patients and 20 healthy volunteers. Phosphorus and parathormone were also determined in the patient group.Results25OHD was significantly lower in patients than controls (P = 0.008). There was a statistically significant difference between both groups regarding suboptimal Vit. D levels (P = 0.007).ConclusionPatients with PV have significantly lower serum vitamin D levels in comparison to controls and that these low levels were not related to age, BMI or pattern of sun exposure. The associated Vitamin D insufficiency in patients with PV may possibly exacerbate their disease through various immune related mechanisms.