Correction: Populations of arable weed species show intra-specific variability in germination base temperature but not in early growth rate.

[This corrects the article DOI: 10.1371/journal.pone.0240538.].

The utility of the 'Arable Weeds and Management in Europe' database: Challenges and opportunities of combining weed survey data at a European scale.

Over the last 30 years, many studies have surveyed weed vegetation on arable land. The 'Arable Weeds and Management in Europe' (AWME) database is a collection of 36 of these surveys and the associated management data. Here, we review the challenges associated with combining disparate datasets and explore some of the opportunities for future research that present themselves thanks to the AWME database. We present three case studies repeating previously published national scale analyses with data from a larger spatial extent. The case studies, originally done in France, Germany and the UK, explore various aspects of weed ecology (community composition, management and environmental effects and within-field distributions) and use a range of statistical techniques (canonical correspondence analysis, redundancy analysis and generalised linear mixed models) to demonstrate the utility and versatility of the AWME database. We demonstrate that (i) the standardisation of abundance data to a common measure, before the analysis of the combined dataset, has little impact on the outcome of the analyses, (ii) the increased extent of environmental or management gradients allows for greater confidence in conclusions and (iii) the main conclusions of analyses done at different spatial scales remain consistent. These case studies demonstrate the utility of a Europe-wide weed survey database, for clarifying or extending results obtained from studies at smaller scales. This Europe-wide data collection offers many more opportunities for analysis that could not be addressed in smaller datasets; including questions about the effects of climate change, macro-ecological and biogeographical issues related to weed diversity as well as the dominance or rarity of specific weeds in Europe.

Muscular Activation Patterns During Exercise on the Treadmill, Stepper, and Elliptical Trainer.

ABSTRACT: Eken, MM, Withers, A, Flanagan, K, Burger, J, Bosch, A, and Lamberts, RP. Muscular activation patterns during exercise on the treadmill, stepper, and elliptical trainer. J Strength Cond Res 36(7): 1847-1852, 2022-Because of the low-impact, the stepper and elliptical trainer are popular alternatives to running when runners sustain running-related injuries. Muscular effort is expected to be lower during exercise on the stepper and elliptical trainer compared with running. The aim of this study was to quantify this by comparing muscular effort when exercising at similar moderate-to-high exercise intensities on a treadmill, stepper, and elliptical trainer. Seventeen well-trained runners (V̇o2max: 53.3 ml·min-1·kg-1 [male: n = 9], 44.8 ml·min-1·kg-1 [female: n = 8]; average peak treadmill running speed: 18.7 km·h-1 [male], 16.3 km·h-1 [female]) performed exercise at submaximal levels (60%-70%-80% of peak workload) on the treadmill, stepper, and elliptical trainer. Peak workload was determined during peak exercise tests on separate days. Surface electromyography was recorded from lower extremity muscles. Root-mean-squared (RMS) values were calculated and compared between exercise modalities and submaximal levels. Significance was set at p < 0.05. Root-mean-squared levels of lower extremity muscles were significantly reduced during exercise on the stepper and elliptical trainer compared with treadmill running (p < 0.05, except for quadriceps (p > 0.05). Overall, similar RMS levels were found on stepper and elliptical trainer (p > 0.05), whereas in several cases higher RMS levels were found on the stepper compared with elliptical trainer (p < 0.05). These findings support clinical expectations that exercise on the stepper and elliptical trainer reduces muscular effort up to 60% compared with (treadmill) running, and therefore can be effective training modalities during rehabilitation from running-related injuries by restricting impact on lower extremities.

Physiological and Metabolic Responses to Exercise on Treadmill, Elliptical Trainer, and Stepper: Practical Implications for Training.

Elliptical trainers and steppers are proposed as useful exercise modalities in the rehabilitation of injured runners due to the reduced stress on muscles and joints when compared to running. This study compared the physiological responses to submaximal running (treadmill) with exercise on the elliptical trainer and stepper devices at three submaximal but identical workloads. Authors had 18 trained runners (male/female: N = 9/9, age: mean ± SD = 23 ± 3 years) complete randomized maximal oxygen consumption tests on all three modalities. Submaximal tests of 3 min were performed at 60%, 70%, and 80% of peak workload individually established for each modality. Breath-by-breath oxygen consumption, heart rate, fuel utilization, and energy expenditure were determined. The value of maximal oxygen consumption was not different between treadmill, elliptical, and stepper (49.3 ± 5.3, 48.0 ± 6.6, and 46.7 ± 6.2 ml·min-1·kg-1, respectively). Both physiological measures (oxygen consumption and heart rate) as well as carbohydrate and fat oxidation differed significantly between the different exercise intensities (60%, 70%, and 80%) but did not differ between the treadmill, elliptical trainer, and stepper. Therefore, the elliptical trainer and stepper are suitable substitutes for running during periods when a reduced running load is required, such as during rehabilitation from running-induced injury.

Populations of arable weed species show intra-specific variability in germination base temperature but not in early growth rate.

Key plant traits affecting growth performance can differ among and within species, influencing competitive plant community dynamics. We determined the intra-specific variability of germination base temperature among 13 arable weed species and the seedlings' early post-emergence relative growth rate among 21 species in climate chamber and green house experiments. Intra-specific variability was quantified with two seed populations (originating from contrasting climate in Germany & France) for the germination base temperature of 6 species and for the early growth rate of 16 species. Inter-specific variability for both traits was always higher than intra-specific variability. Within a given species, we found that germination base temperatures were higher in seeds stemming from colder climate populations. Seedling relative growth rates did not differ between seed populations. Models simulating weed growth should reflect these differences in germination traits among populations, especially when they are used for weed community assembly studies in a local to regional extent.