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opencc-zeroSep 2020View details →

Data from: Experimental migration upward in elevation is associated with strong selection on life history traits

One of the strongest biological impacts of climate change has been the movement of species poleward and upward in elevation. Yet, what is not clear, is the extent to which the spatial distribution of locally adapted lineages and ecologically important traits may also shift with continued climate change. Here, we take advantage of a transplant experiment mimicking up-slope seed dispersal for a suite of ecologically-diverse populations of yellow monkeyflower (Mimulus guttatus sensu lato) into a high-elevation common garden during an extreme drought period in the Sierra Nevada mountains, California, USA. We use a demographic approach to quantify fitness and test for selection on life history traits in local vs. lower-elevation populations and in normal vs. drought years to test the potential for up-slope migration and phenotypic selection to alter the distribution of key life history traits in montane environments. We find that lower-elevation populations tend to outperform local populations, confirming the potential for up-slope migration. Although selection generally favored some local montane traits, including larger flowers and larger stem size at flowering, drought conditions tended to select for earlier flowering typical of lower elevation genotypes. Taken together, this suggests that monkeyflower lineages moving upward in elevation could experience selection for novel trait combinations, particularly under warmer and drier conditions that are predicted to occur with continued climate change.

opencc-by-4.0Sep 2020View details →

Data from Koch et al. 2020 Evolution: Genetic variance in fitness and its cross-sex covariance predict adaptation during experimental evolution.

Abstract In presence of rapid environmental changes, it is of particular importance to assess the adaptive potential of populations, which is mostly determined by the additive genetic variation (VA) in fitness. In this study we used Tribolium castaneum (red flour beetles) to investigate its adaptive potential in three new environmental conditions (Dry, Hot, Hot-Dry). We tested for potential constraints that might limit adaptation, including negative genetic covariance between female and male fitness.  Based on VA estimates for fitness, we expected the highest relative fitness increase in the most stressful condition Hot-Dry and similar increases in single stress conditions Dry and Hot. High adaptive potential in females in Hot was reduced by a negative covariance with male fitness. We tested adaptation to the three conditions after 20 generations of experimental evolution and found that observed adaptation mainly matched our predictions. Given that body size is commonly used as a proxy for fitness, we also tested how this trait and its genetic variance (including non-additive genetic variance) were impacted by environmental stress. In both traits, variances were sex and condition dependent, but they differed in their variance composition, cross-sex and cross-environment genetic covariances, as well as in the environmental impact on VA.   Method Strain and environmental conditions We used the Tribolium castaneum Cro1 strain collected from a wild population in 2010 and adapted to lab standard conditions (33°C, 70% relative humidity) for more than 20 generations. Beetles were kept in 24h darkness on organic wheat flour mixed with 10% organic baker's yeast. We sterilized flour and yeast by heating them for 12h at 80°C before use. To test for adaptation to new environmental conditions we used replicate lines and exposed them to three treatments and Control conditions. The conditions in the treatments were: Dry: 33°C and 30% relative humidity; Hot: 37°C and 70% r. h.; Hot-Dry: 37°C and 30% r. h.   Crossing, fitness assay and measurement of body size In order to be able to estimate genetic variances, we applied a split-brood paternal half-sib breeding design.  We produced 147 half-sib families by mating virgin males to three virgin females. Half- as well as full-sib families were split across all conditions. Male and female offspring (four females and two males per full-sib family and condition) were separated at the pupal stage and transferred to 10 mL tubes with 1 g of medium and remained there until they were used for the fitness assay eight weeks later. To estimate fitness, we mated each virgin male with two unrelated virgin females from the same condition in 15mL tube with 1g medium. The male was removed after 24h and females transferred into two separate tubes. Females were removed from the tubes after one week of egg laying, and 9g medium was added to provide food for the developing offspring. After five weeks the number of adult offspring was counted. While we conducted the matings for the fitness assay, we followed a specific crossing design and always crossed two pairs of full-sib families. Individuals resulting from these crosses (the F2 genaration) were double first cousins. Body size was measured in the F2, i.e. in the offspring of beetles that were used for the fitness assay. To estimate body size, we used the centroid size of the abdominal segment IV as proxy for total size since it can be measured more accurately than dry weight in very small insects and shows a high correlation with body mass.   Experimental evolution We used ten replicate lines per condition originating from the same ancestral population (Cro1) and let them adapt for 20 generations. Each new generation was set up by randomly selecting 120 pupae and placing them into a new vial with 70g medium. One selection line in Dry became extinct. Adult beetles of generation 20 from all selection lines were transferred to control conditions, in which they stayed for one week to mate and lay eggs. After removal of the adults, we waited until their offspring had reached the pupal stage and separated males and females. These individuals (generation 21) developed completely in control conditions. When they had reached the adult stage, each virgin male was mated with a virgin female of the same selection line and their offspring was transferred to all four conditions in the egg stage, resulting in full-sib families split across all conditions . As soon as these offspring (generation 22) had reached the pupal stage, males and females were separated. To compare fitness of different selection lines and test for adaptation, a virgin male and a virgin female of the same selection line in the same condition, but from different families were mated and the number of adult offspring produced within four days of mating and egg laying was used as a fitness estimate.     Files This data publication contains the following files: Fitness_data.txt: Fitness data (offspring number) of the first generation in new environmental conditions. ANIMAL: ID of female individuals; male: ID of mating partner, father of the offspring; fitness: number of adult offspring per female produced within one week of egg laying; condition: condition under which the individuals grew up, mated, reproduced (CTL: control, D: dry, H: hot, HD: hot-dry, see Methods for details); MOTHER: mother of the female; Batch: samples where fitness assay was started on the same day   Size_data.txt: Centroid size of abdominal segment IV. ANIMAL: ID of measured individuals; condition: condition under which the individuals grew up (CT: control, D: dry, H: hot, HD: hot-dry, see Methods for details); sex: sex of individuals (f: female, m: male); AS: centroid size [Pixel] of abdominal segment IV; Mother: ID of their mother; batch: Batches represent individuals that grew up at the same time, and thus accounts for variations in the medium or lab temperature   Pedigree.txt: Pedigree of measured individuals. ANIMAL: individual ID ; MOTHER: mother ID; FATHER: father ID   Transplant_data.txt: Offspring number of different selection lines under different conditions after 20 generations of experimental evolution. Line: Selection-line ID; Selection: condition, in which the selection-line spent 20 generations (CT: Control; D: Dry; Hot; HD: Hot-Dry); Fam: each selection line consisted of several families; Treatment: condition, in which offspring number was measured; offspring: number of adult offspring that a female produced within four days of egg-laying

opencc-zeroSep 2019View details →

Data from: Evolution alters post-invasion temporal dynamics in experimental communities.

1. The causes and consequences of temporal variation in the abundance of organisms constitute central themes in ecological inquiry. Rapid evolution can occur over ecological time scales, potentially resulting in altered temporal variation in abundance and complicating inferences about the consequences of temporal variation. 2. We assessed whether evolution altered the temporal variability in species' abundances in simple assemblages of species. We then compared experimental results to predictions from two-species models to better understand our results in the context of competitive and predator-prey interactions. 3. We compared founder populations and their evolved descendants in experimental communities of ciliates and rotifers. Using a series of orthogonal contrasts, we then evaluated whether: 1) evolutionary history of invaders or 2) residents, 3) coevolution among invaders and residents, and 4) invasion itself altered temporal variability in species abundances following invasion by a novel species. Using two-species competition and predator-prey models, we also generated predictions to better understand the effects of evolution on temporal variation in the abundances of interacting species. Finally, we compared experimental and modeling results to aid in the interpretation of which interspecific interactions might be affected by ongoing evolution in our communities. 4. In experimental populations, differing evolutionary histories resulted in significant differences among treatments in abundances and temporal variation in abundances of both resident and invading species. For the contrasts, we found evidence that evolutionary history of the invader and residents, coevolution among invaders and residents, and invasion itself affected temporal variability in abundance, but the importance of each differed for the two communities and the species within those communities. When comparing experimental results to model predictions, the increased abundance and decreased temporal variation of one invader, Euplotes daidaleos, are potentially consistent with evolution resulting in reduced attack rates in the novel community. 5. Evolutionary history alone can affect temporal variation in the abundances of species, generating important consequences for interspecific interactions among species and complicating inferences about the consequences of temporal variability in biological communities.

opencc-zeroDec 2020View details →

Data from: Experimental evaluation of spectral efficiency from a circular array antenna producing a Laguerre-Gauss mode

We present the 4D volumetric electromagnetic field measurements (x, y, z and frequency) of the complex radiated field produced by an 8-element circular antenna array. The array is designed to produce a Laguerre-Gauss (LG) mode l = -1 over the frequency range of 9 - 10 GHz. We evaluate our findings in terms of far-field LG mode purity and spectral efficiency in terms of the QAM modulation scheme that can be supported. The application of LG modes in radio systems is as a means of multiplexing several data streams onto the same frequency, polarisation and time slot, thus making highly spectrally efficient transmission system or enhancing radar systems by means of exploiting mode behaviour as an additional degree of freedom. Our results show that for the circular antenna array, we find that mode purity allows BPSK or QPSK modulation over a 0.3GHz bandwidth. Closer to the antennas' design frequency, 256QAM modulation may be used over a 0.05 GHz band. We anticipate the practical insights provided in this paper to contribute to the successful design of such systems.

opencc-by-4.0Oct 2020View details →

Experimental data: measurement campaign Hintereisferner Experiment, HEFEX.

The HEFEX micrometeorological measurement campaign was conducted during three weeks in August 2018. Measurement towers were installed on the 1. and 2. August and removed on 22. August. The measurement network consisted of five 3-m tripod towers  located at an along- and an across-glacier transect to capture the spatial variations of the atmospheric flow system at the glacier and associated heat exchange processes. The across-glacier transect consisted of three turbulence towers installed from the peripheral zones of the glacier towards the centreline. The location of the across-glacier transect coincides with where the valley of Langtaufererjochferner discharges into the valley of the Hintereisferner glacier. In this area, thermal flows from the surrounding area were hypothesized to influence the surface of Hintereisferner. All stations were installed at comparatively flat areas of the glacier with slope angles varying between 6 and 8°. Measurement towers were installed directly at the ice surface. Due to pronounced changes in the ice surface caused by strong ice melt during the measurement campaign, frequent visual inspection and small adjustments to the location of the towers were essential for good data quality. This mainly consisted of repositioning the tower feet to ensure the tower stability and re-levelling the sensors. Post-processing of data, i.e. correction of data for height changes and rotation of the mast further ensured data quality

opencc-by-4.0Oct 2020View details →

Unmanned Aerial Vehicle (UAV) data acquired over an experimental area of the UFSM campus Frederico Westphalen, at October 20, 2020, Rio Grande do Sul, Brazil

Fábio Marcelo Breunig¹ (author) ¹ Universidade Federal de Santa Maria, Departamento de Engenharia Florestal, Frederico Westphalen, Rio Grande do Sul, Brasil. E-mail: breunig@ufsm.br Title:   Unmanned Aerial Vehicle (UAV) data acquired over an experimental area of the UFSM campus Frederico Westphalen, at October 20, 2020, Rio Grande do Sul, Brazil Data description:   The data were acquired from an aerial survey conducted with an Unmanned Aerial Vehicle (UAV, also Drone) covering an experimental area of the Federal University of Santa Maria – UFSM in the municipality of Frederico Westphalen, in the Rio Grande do Sul, Brazil (Figure 1). The climate of the region is subtropical (Cfa in the Köppen-Geiger classification) with an average annual temperature of 18 °C and annual precipitation of 1919 mm (<a href="https://www.sciencedirect.com/science/article/pii/S0303243419309481#bib0015">Alvares et al., 2013</a>). The rainfall is well distributed throughout the year.   Figure 1. Location of the site of data acquisition. Based on Google Earth Pro scenes. The KML and KMZ are appended to the files. UAV and camera settings for the acquisition (Specifications Table):   Parameters Specification/value Date (YYYYMMDD): 20201020 Time of day (BRT = -3) 11 h a.m. UAV – Drone - Camera Matrice 100 X3 Fly high (meters above ground) 80 m View angle 90° automatic mode. Sky conditions ( x ) Clear sky (  ) Low cloud coverage (some clouds) (  ) Completely cloudy Wind condition ( x ) no wind (  ) Low speed (  ) High speed wind Approximate data acquisition duration 16 minutes Total of photographs acquired 224 Across track coverage 80% Cross-track coverage 80% Fly planning software Pix4D Capture   For more information contact: Fábio Marcelo Breunig, <a href="mailto:breunig@ufsm.br">breunig@ufsm.br</a> An example of the mosaic is showed (Figure 2), referring to a screen capture of Agisoft Metashape (Agisoft LLC, 11 Degtyarniy per., St. Petersburg, Russia, 191144) and, the workflow adopted.   Figure 2. The capture of an orthomosaic and processing workflow     References to the main project/publications:   Breunig, Fabio Marcelo. CONESAT – Monitoring the CONESUL using remote sensing data. Project. Federal University of Santa Maria, Campus of Frederico Westphalen. Brazil. Available at: <https://www.researchgate.net/project/CONESAT-Monitoring-the-CONESUL-using-remote-sensing-data>.   Breunig, Fabio Marcelo. Integration of multiscale remote sensing data in the precision agriculture and silviculture (in Portuguese: Integração de dados multiescala de sensoriamento remoto na agricultura e silvicultura de precisão). Project. National Council for Scientific and Technological Development (CNPq). Grant 113769/2018-0   Breunig, Fabio Marcelo. Combination of UAV, PlanetScope, Landsat and Sentinel-2 images to precision silviculture and agriculture in a subtropical region (in Portuguese: Combinação de imagens de VANT, PlanetScope, Landsat e Sentinal-2 para a silvicultura e agricultura de precisão em uma região subtropical). Project of the National Council for Scientific and Technological Development (CNPq). Grant 305084/2020-8   Acknowledgments:   This work was supported by the National Council for Scientific and Technological Development (CNPq) (Grants 113769/2018-0, 312081/2013-8, 478085/2013-3 and, 305084/2020-8) and Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul  (Grant 23830.388.22048.19092016).   Other considerations   PS. A pdf file is also attached with this description   Declaration of Competing Interest   The author declares that he has no competing interests or personal relationships that have or could be perceived to have influenced the work reported in this report.   References associated:   Breunig, Fábio Marcelo (2017, July 7). Unmanned Aerial Vehicle (UAV) data acquired over a subtropical forest area of the UFSM campus Frederico Westphalen, at July 7, 2017, Rio Grande do Sul, Brazil. Zenodo. http://doi.org/10.5281/zenodo.4327943 Alvares, Clayton Alcarde, José Luiz Stape, Paulo Cesar Sentelhas, José Leonardo De Moraes Gonçalves, and Gerd Sparovek, ‘Köppen’s Climate Classification Map for Brazil’, Meteorologische Zeitschrift, 22 (2013), 711–28 <https://doi.org/10.1127/0941-2948/2013/0507> Breunig, Fábio Marcelo (2019): UAV images acquired over the UFSM campus in Frederico Westphalen, RS, Brazil. Universidade Federal de Santa Maria, PANGAEA, https://doi.org/10.1594/PANGAEA.897548 Breunig, Fábio Marcelo (2019): UAV derived orthomosaic over the “prainha” in the municipality of Iraí, Rio Grande do Sul, Brazil. Universidade Federal de Santa Maria, PANGAEA, https://doi.org/10.1594/PANGAEA.897909 Sestari, Geovane (2019): RPAS orthomosaic over the remnant of rainforest on UFSM/IFFar campus in the municipality of Frederico Westphalen, Rio Grande do Sul, Brazil. PANGAEA, https://doi.org/10.1594/PANGAEA.910114 Breunig, Fábio Marcelo  (2017, July 11). Unmanned Aerial Vehicle (UAV) data acquired over a subtropical forest area of the UFSM campus Frederico Westphalen, at July 11, 2017, Rio Grande do Sul, Brazil. Zenodo. http://doi.org/10.5281/zenodo.4328340

opencc-by-4.0Dec 2020View details →

Experimental Data for "Seismic wave attenuation and dispersion due to partial fluid saturation: Direct measurements and numerical simulations based on X-Ray CT"

Experimental Data from a Berea sandstone sample. Includes X-ray CT scans and mechanical response of sample. Abstract Quantitatively assessing seismic attenuation caused by fluid pressure diffusion (FPD) in partially saturated rocks is challenging because of its sensitivity to the spatial fluid distribution. To address this challenge we performed depressurisation experiments to induce the exsolution of carbon dioxide from water in a Berea sandstone sample. In a first set of experiments we used medical X-ray computed tomography (CT) to characterise the fluid distribution. At an equilibrium pressure of ~1 MPa and applying a fluid pressure decline rate of ~0.6 MPa per minute, we allowed a change in saturation of less than 1 %. The gas was heterogeneously distributed along the length of the sample, with most of the gas exsolving near the sample outlet. In a second set of experiments, at the same pressure and temperature, following a very similar exsolution protocol, we measured the frequency dependent attenuation and modulus dispersion between 0.1 and 1000 Hz using the forced oscillation method. We observed significant attenuation and dispersion in the extensional and bulk deformation modes, however not in the shear mode. Lastly, we use the fluid distribution derived from the X-ray CT as an input for numerical simulations of FPD to compute the attenuation and modulus dispersion. The numerical solutions are in close agreement with the attenuation and modulus dispersion measured in the laboratory. Our methodology allows for accurately relating attenuation and dispersion to the fluid distribution, which can be applied to improving the seismic monitoring of the subsurface.

Data from: Are house sparrow populations limited by the lack of cavities in urbanized landscapes? an experimental test.

Current urban policies are associated with deep changes in urban structures, which may impoverish urban biodiversity. A major concern is the disappearance of nesting sites for wild vertebrate species living in urban areas. New urban structures without any cracks or cavities may especially preclude cavity nesters from breeding in cities and they may cause population declines. In that context, we experimentally investigated this question in an urban exploiter bird species (the house sparrow, Passer domesticus), which is dramatically declining in most European cities. To test if the lack of cavities is limiting house sparrow populations in urban areas, we equipped 11 sites along an urbanization gradient with nest boxes and we then evaluated the rate of occupancy of these nest-boxes. This urbanization gradient was characterized by very rural places (isolated farms) and moderately urbanized areas (town of medium size, i.e. 60 000 inhabitants). Surprisingly, rural nest boxes were more occupied than urban ones, suggesting that cavity availability is probably more constraining in rural areas relative to urban ones. Therefore, our study suggests that urban house sparrow populations are probably not constrained by a lack of nesting sites in medium size cities with urban designs similar to our city of interest (Niort, Western France). This hypothesis definitely needs now to be tested in further urban landscapes (e.g. large cities and urban landscapes with other architecture and management policies).

Data from: No selection for change in polyandry under experimental evolution

What drives mating system variation is a major question in evolutionary biology. Female multiple mating (polyandry) has diverse evolutionary consequences, and there are many potential benefits and costs of polyandry. However, our understanding of its evolution is biased towards studies enforcing monandry in polyandrous species. What drives and maintains variation in polyandry between individuals, genotypes, populations and species remains poorly understood. Genetic variation in polyandry may be actively maintained by selection, or arise by chance if polyandry is selectively neutral. In Drosophila pseudoobscura, there is genetic variation in polyandry between and within populations. We used isofemale lines to found replicate populations with high or low initial levels of polyandry, and tracked polyandry under experimental evolution over seven generations. Polyandry remained relatively stable, reflecting the starting frequencies of the experimental populations. There were no clear fitness differences between high versus low polyandry genotypes, and there was no signature of balancing selection. We confirmed these patterns in direct comparisons between evolved and ancestral females, and found no consequences of polyandry for female fecundity. The absence of differential selection even when initiating populations with major differences in polyandry casts some doubt on the importance of polyandry for female fitness.

opencc-zeroDec 2014View details →

Data from: A controlled quasi-experimental study of an educational intervention to reduce the unnecessary use of antimicrobials for asymptomatic bacteriuria

Background: Asymptomatic bacteriuria (ABU) should only be treated in cases of pregnancy or in-patients undergoing urologic procedures; however, unnecessary treatment of ABU is common in clinical practice. Objective: To identify risk factors for unnecessary treatment and to assess the impact of an educational intervention focused on these risk factors on treatment of ABU. Design: Quasi-experimental study with a control group. Setting: Two tertiary teaching adult care hospitals. Participants: Consecutive patients with positive urine cultures between January 30th and April 17th, 2012 (baseline) and January 30th and April 30th, 2013 (intervention). Intervention: In January 2013, a multifaceted educational intervention based on risk factors identified during the baseline period was provided to medical residents (monthly) on one clinical teaching unit (CTU) at one hospital site, with the CTU of the other hospital serving as the control. Results: During the baseline period, 160/341 (46.9%) positive urine cultures were obtained from asymptomatic patients at the two hospitals, and 94/160 (58.8%) were inappropriately treated with antibiotics. Risk factors for inappropriate use included: female gender (OR 2.1, 95% CI 1.1-4.3), absence of a catheter (OR 2.5, 1.2-5), bacteriuria versus candiduria (OR 10.6, 3.8-29.4), pyuria (OR 2.0, 1.1-3.8), and positive nitrites (OR 2.2, 1.1-4.5). In 2013, only 2/24 (8%) of ABU patients were inappropriately treated on the intervention CTU as compared to 14/29 (52%) on the control CTU (OR 0.10; 95% CI 0.02-0.49). A reduction was also observed as compared to baseline on the intervention CTU (OR 0.1, 0.02-0.7) with no significant change noted on the control CTU (OR 0.47, 0.13-1.7). Conclusions: A multifaceted educational intervention geared towards medical residents with a focus on identified risk factors for inappropriate management of ABU was effective in reducing unnecessary antibiotic use.

opencc-zeroDec 2011View details →

Data from: Experimental evidence of early costs of reproduction in conspecific viviparous and oviparous lizards

Reproduction entails costs, and disentangling the relative importance of each stage of the reproductive cycle may be important to assess the costs and benefits of different reproductive strategies. We studied the early costs of reproduction in oviparous and viviparous lizard females of the bimodal reproductive species Zootoca vivipara. Egg-retention time in oviparous females is approximately one third of the time in viviparous females. We compared the vitellogenesis and egg-retention stages which are common to both reproductive modes. Precisely, we monitored the thermoregulatory behaviour, the weight gain and the immunocompetence of the females. Moreover, we injected an antigen in half of the females (immune challenge) to study the trade-offs between reproductive mode and immune performance, and between different components of the immune system. Finally, we experimentally induced parturition in viviparous females at the time of egg-laying in oviparous females. Oviparous and viviparous females did not show strong differences in response to the immune challenge. However, viviparous females spent more time thermoregulating while partially hidden and gained more weight than oviparous females. The greater weight gain indicates that the initial period of egg-retention is less costly for viviparous than for oviparous females or that viviparous females are able to save and accumulate energy at this period. This energy may be used by viviparous females to cope with the subsequent costs of the last two thirds of the gestation. Such an ability to compensate the higher costs of a longer egg-retention period may account for the frequent evolution of viviparity in squamate reptiles.

opencc-zeroDec 2017View details →

Data from: Experimental evidence that female rhesus macaques (Macaca mulatta) perceive variation in male facial masculinity

Among many primate species, face shape is sexually dimorphic, and male facial masculinity has been proposed to influence female mate choice and male-male competition. However, whether conspecifics pay attention to facial masculinity has only been assessed in humans. Here, working with free-ranging rhesus macaques, Macaca mulatta, we used a two-alternative look-time experiment to test whether females perceive male facial masculinity. We presented 107 females with pairs of images of male faces – one more masculine and one more feminine – and recorded their looking behaviour. Females looked toward the masculine face longer than the feminine face in more trials than predicted by chance. Although there was no overall difference in average look-time between masculine and feminine faces across all trials, females looked significantly longer at masculine faces in a subset of trials for which the within-pair difference in masculinity was most pronounced. Additionally, the proportion of time subjects looked toward the masculine face increased as the within-pair difference in masculinity increased. This study provides evidence that female macaques perceive variation in male facial shape, a necessary condition for intersexual selection to operate on such a trait. It also highlights the potential impact of perceptual thresholds on look-time experiments.

Data from: Experimental N and P additions alter stream macroinvertebrate community composition via taxon‐level responses to shifts in detrital resource stoichiometry

1. Increases in nitrogen (N) and phosphorus (P) availability are changing animal communities, partly by altering stoichiometric imbalances between consumers and their food. Testing relationships between resource stoichiometry and consumer assemblage structure requires ecosystem-level manipulations that have been lacking to date. 2. We analyzed patterns of macroinvertebrate community composition in five detritus-based headwater streams subject to experimental whole-stream N and P additions that spanned a steep gradient in dissolved N:P ratio (2:1, 8:1, 16:1, 32:1, 128:1) over two years, following a one-year pre-treatment period. 3. We predicted that shifts in leaf litter stoichiometry would drive overall patterns of community composition via greater responses of shredders to enrichment than other taxa, as shredders dominate primary consumer biomass and experience larger consumer-resource elemental imbalances than other functional groups in stream ecosystems. Specifically, we expected litter C:P to be a significant predictor of shredder biomass given the greater relative imbalances between shredder and litter C:P than C:N. Finally, we tested whether shredder responses to enrichment were related to other taxon-level traits, including body size and stoichiometry, larval lifespan and growth rate. 4. Whole-community composition shifted similarly across the five streams after enrichment, largely driven by increased shredder and predator biomass. These shifts were limited to the autumn/winter seasons and related to decreased leaf litter C:P, highlighting important links between the quality of seasonal litter subsidies and community phenology. 5. Among 10 taxa that drove structural shifts, two declined while other taxa from the same functional/taxonomic groups responded positively, suggesting that specific life-history traits may determine sensitivity to enrichment. 6. Increases in total shredder biomass, and in biomass of several common shredders, were associated with lower litter C:P. Body C:P did not predict shredder response to enrichment. However, weak negative relationships between shredder response and body size, and larval lifespan, suggest that small-bodied and short-lived taxa may be more responsive to shifting resource stoichiometry. 7. Moderate anthropogenic increases in N and P availability affect resource stoichiometry and can alter animal communities, influencing additional food-web and ecosystem properties. We provide support for ecological stoichiometry as a framework for predicting such outcomes based on changes in the elemental composition of resource pools.

opencc-zeroDec 2012View details →

Data from: Sexual selection can remove an experimentally induced mutation load

Sexual selection is argued to be important for the removal of deleterious mutations, promoting population fitness, accelerating adaptation, and compensating for the two-fold cost of sex. Here we induced mutations in the dung beetle Onthophagus taurus using ionizing radiation, and tested the efficacy of sexual selection in their removal. Mutations reduced male precopulatory (strength) and postcopulatory (testes mass) sexual traits. Two generations of sexual selection were sufficient to remove mutations that affected male strength, but not testes mass. Induced mutations did not affect female productivity, which was elevated by sexual selection. Our results provide empirical support for the hypothesis that condition-dependent traits offer a large target for mutational variation, and that sexual selection can purge the genome of deleterious mutations and promote population fitness.

opencc-zeroDec 2017View details →

Data from: Asymmetric competitive effects during species range expansion: an experimental assessment of interaction strength between 'equivalent' grazer species at their range overlap

1. Biotic interactions are central to the development of theory and concepts in community ecology; experimental evidence has shown their strong effects on patterns of population and community organization and dynamics over local spatial scales. The role of competition in determining range limits and preventing invasions at biogeographic scales is more controversial, partly because of the complexity of processes involved in species colonization of novel habitats and the difficulties in performing appropriate manipulations and controls. 2. We examined experimentally whether competition is likely to affect poleward range expansion hindering or facilitating the establishment of the limpet Scurria viridula along the southeastern Pacific rocky shore (30°S, Chile) in the region occupied by the congeneric S. zebrina. We also assessed whether competition with the "invader" or range expanding species could reduce individual performance of the 'native' S. zebrina and depress local populations 3. Geographic field surveys were conducted to characterize the abundance and identity of limpets along the south-eastern Pacific coast from 18°S to 41°S, and the micro-scale (few cm) spatial distribution across the range overlap of the two species. Field-based competition experiments were conducted at the southern leading edge of the range of S. viridula (33°S) and at the northern limit of S. zebrina (30°S). 4. Field surveys showed poleward range expansion of S. viridula of ca. 210 km since year 2000, with an expansion rate of 13.1 km year -1. No range shift was detected for S. zebrina. The resident S. zebrina had significant negative effects on the growth rate of the invading juvenile S. viridula, while no effect of the latter was found on S. zebrina. Spatial segregation between species was found at the scale of cms. 5. Our results provide novel evidence of an asymmetric competitive effect of a resident species on an invader, which may hamper further range expansion. No negative effect of the invader on the resident species was detected. This study highlights the complexities of evaluating the role of species interactions in setting range limits of species, but showed how interspecific competition might slow the advance of an invader by reducing individual performance and overall population size at the advancing front.

Data from: Increasing plant diversity of experimental grasslands alters the age and growth of Plantago lanceolata from younger and faster to older and slower

The persistence of plant populations depends on the ability of individuals to cope with the conditions provided by the community. So far, it is not known whether differences in the diversity and composition of plant communities affect the age structure of plant populations or the expression of stem anatomical traits reflecting investment into plant growth and storage. We analyzed annual growth rings in the secondary xylem and measured stem anatomical traits in individuals from 18 populations of Plantago lanceolata growing in a 12-year old grassland biodiversity experiment (Jena Experiment). Plant individuals of P. lanceolata were on average older and reproduced later with increasing species richness. Individuals of P. lanceolata were slightly younger and the age distribution within populations skewed to younger individuals in the presence of grasses. The presence of legumes did not affect mean age, but led to a more even age distribution within populations. The width of growth-related tissues (xylem, phloem, phellem) decreased with increasing species richness. Plant diversity-effects on storage-related tissues (pith, cortex) were less consistent, as pith showed increasing width with species richness, while cortex did not change with plant diversity. Our results imply that plant diversity effects on population age structure and the expression of stem anatomical traits of P. lanceolata reflect a trade-off: growth and turnover is fast at low diversity (younger age, higher allocation to growth-related tissue, faster generative reproduction), while it is slow at high diversity (older age, higher allocation to storage-related tissue, later generative reproduction).

opencc-zeroDec 2019View details →

Data from: The variation of grain size distribution in rock granular material in seepage process considering the mechanical-hydrological-chemical coupling effect: An experimental research

As a common solid waste in geotechnical engineering, rock granular material should be properly treated and recycled. Rock granular material often coexists with water when it is used as the filling material in geotechnical engineering. Water flowing in rock granular materials is a complex progress with the mechanical-hydrological-chemical (MHC) coupling effect, i. e. the water scours in the gaps and spaces in the rock granular material structure, produces chemical reactions with rock grains, rock grains squeeze each other under the water pressure and compression leading re-breakage and producing secondary rock grains, the fine rock grains are migrated with water and rushed out. In this process, rock grain size distribution (GSD) changes, it affects the physical and mechanical characteristics of the rock granular materials, and even influences the seepage stability of the rock granular materials. To study the variation of GSD in the rock granular material considering the MHC coupling effect after the seepage process, seepage experiments of rock grain samples are carried out and analyzed in this paper. The result is expected to have a positive impact on further studies of the properties of the rock granular material.

opencc-zeroFeb 2020View details →

Data from: Transmural impedance detects graded changes of inflammation in experimental colitis

Ulcerative colitis is a chronic disease in which the mucosa of the colon or rectum becomes inflamed. An objective biomarker of inflammation will provide quantitative measures to support qualitative assessment during an endoscopic examination. Previous studies show that transmural electrical impedance is a quantifiable biomarker of inflammation. Here we hypothesise that impedance detects spatially restricted areas of inflammation, thereby allowing the distinction between regions that differ in their severity of inflammation. A platinum ball electrode (3.2 mm² surface area) was placed into normal or 2,4,6-trinitrobenzene sulfonic acid (TNBS) inflamed colonic regions of rats and impedance measurements obtained by passing current between the intraluminal and a large subcutaneous return electrode. Histology of the colon was correlated with impedance measurements. The impedance of normal tissue was 1.6-1.8 kOhms. Following TNBS injection, impedance significantly decreased within the inflammatory penumbra (P < 0.05), and decreased more in the inflammatory epicentre (P = 0.02). Histological damage correlated with impedance values (P < 0.05). Thus, impedance values of 1.6-1.8 kOhms, 1.3-1.4 kOhms and 1.0 – 1.1 kOhms were predictors of normal, mildly inflamed and moderately inflamed tissue, respectively. In conclusion, transmural impedance is a real-time, in vivo biomarker of mucosal integrity, and distinguishes between severities of intestinal inflammation.

opencc-zeroDec 2014View details →

Data from: Does predation risk affect mating behavior? An experimental test in dumpling squid (Euprymna tasmanica)

Introduction: One of the most important trade-offs for many animals is that between survival and reproduction. This is particularly apparent when mating increases the risk of predation, either by increasing conspicuousness, reducing mobility or inhibiting an individual's ability to detect predators. Individuals may mitigate the risk of predation by altering their reproductive behavior (e.g. increasing anti-predator responses to reduce conspicuousness). The degree to which individuals modulate their reproductive behavior in relation to predation risk is difficult to predict because both the optimal investment in current and future reproduction (due to life-history strategies) and level of predation risk may differ between the sexes and among species. Here, we investigate the effect of increased predation risk on the reproductive behavior of dumpling squid (Euprymna tasmanica). Results: Females, but not males, showed a substantial increase in the number of inks (an anti-predator behavior) before mating commenced in the presence of a predator (sand flathead Platycephalus bassensis). However, predation risk did not affect copulation duration, the likelihood of mating, female anti-predator behavior during or after mating or male anti-predator behavior at any time. Conclusions: Inking is a common anti-predator defense in cephalopods, thought to act like a smokescreen, decoy or distraction. Female dumpling squid are probably using this form of defense in response to the increase in predation risk prior to mating. Conversely, males were undeterred by the increase in predation risk. A lack of change in these variables may occur if the benefit of completing mating outweighs the risk of predation. Prioritizing current reproduction, even under predation risk, can occur when the chance of future reproduction is low, there is substantial energetic investment into mating, or the potential fitness payoffs of mating are high.