Systematic distributions of interaction strengths across tree interaction networks yield positive diversity-productivity relationships.

Understanding the mechanisms underlying diversity-productivity relationships (DPRs) is crucial to mitigating the effects of forest biodiversity loss. Tree-tree interactions in diverse communities are fundamental in driving growth rates, potentially shaping the emergent DPRs, yet remain poorly explored. Here, using data from a large-scale forest biodiversity experiment in subtropical China, we demonstrated that changes in individual tree productivity were driven by species-specific pairwise interactions, with higher positive net pairwise interaction effects on trees in more diverse neighbourhoods. By perturbing the interactions strength from empirical data in simulations, we revealed that the positive differences between inter- and intra-specific interactions were the critical determinant for the emergence of positive DPRs. Surprisingly, the condition for positive DPRs corresponded to the condition for coexistence. Our results thus provide a novel insight into how pairwise tree interactions regulate DPRs, with implications for identifying the tree mixtures with maximized productivity to guide forest restoration and reforestation efforts.

Animal and plant space-use drive plant diversity-productivity relationships.

Plant community productivity generally increases with biodiversity, but the strength of this relationship exhibits strong empirical variation. In meta-food-web simulations, we addressed if the spatial overlap in plants' resource access and animal space-use can explain such variability. We found that spatial overlap of plant resource access is a prerequisite for positive diversity-productivity relationships, but causes exploitative competition that can lead to competitive exclusion. Space-use of herbivores causes apparent competition among plants, resulting in negative relationships. However, space-use of larger top predators integrates sub-food webs composed of smaller species, offsetting the negative effects of exploitative and apparent competition and leading to strongly positive diversity-productivity relationships. Overall, our results show that spatial overlap of plants' resource access and animal space-use can greatly alter the strength and sign of such relationships. In particular, the scaling of animal space-use effects opens new perspectives for linking landscape processes without effects on biodiversity to productivity patterns.

The hidden role of multi-trophic interactions in driving diversity-productivity relationships.

Resource-use complementarity of producer species is often invoked to explain the generally positive diversity-productivity relationships. Additionally, multi-trophic interactions that link processes across trophic levels have received increasing attention as a possible key driver. Given that both are integral to natural ecosystems, their interactive effect should be evident but has remained hidden. We address this issue by analysing diversity-productivity relationships in a simulation experiment of producer communities nested within complex food-webs, manipulating resource-use complementarity and multi-trophic animal richness. We show that these two mechanisms interactively create diverse communities of complementary producer species. This shapes diversity-productivity relationships such that their joint contribution generally exceeds their individual effects. Specifically, multi-trophic interactions in animal-rich ecosystems facilitate producer coexistence by preventing competitive exclusion despite overlaps in resource-use, which increases the realised complementarity. The interdependence of food-webs and producer complementarity in creating biodiversity-productivity relationships highlights the importance to adopt a multi-trophic perspective on biodiversity-ecosystem functioning relationships.

The impact of reference tones on the adjustment of interaural cues.

In the time-intensity trading paradigm, trading ratios are inconsistent in that they differ as a function of which cue is to be adjusted by the listener. Two explanations have been offered: First, the regression model assumes a regression to the interaural parameters of a reference tone played in alternation with the test tone to cause the phenomenon of inconsistent trading ratios. The second explanation is based on an inflated perceptual weighting of the to-be-adjusted cue. The perceptual-weight explanation has been supported by experimental results showing that the phenomenon of inconsistent trading ratios appears even in the absence of a reference tone. Those findings render regression as the sole explanation for inconsistent trading ratios implausible. The experiments presented in this paper address the question whether regression to the parameters of a reference tone plays a role if a reference tone is presented. Three experiments were conducted in which trials with and without reference tone were compared directly. Both within- and between-subject comparisons showed that a reference tone affects trading ratios and location judgments if present. Although regression cannot be the sole explanation for the phenomenon of inconsistent trading ratios it seems to play a role if a reference tone is presented.

The environment to the rescue: can physics help predict predator-prey interactions?

Understanding the factors that determine the occurrence and strength of ecological interactions under specific abiotic and biotic conditions is fundamental since many aspects of ecological community stability and ecosystem functioning depend on patterns of interactions among species. Current approaches to mapping food webs are mostly based on traits, expert knowledge, experiments, and/or statistical inference. However, they do not offer clear mechanisms explaining how trophic interactions are affected by the interplay between organism characteristics and aspects of the physical environment, such as temperature, light intensity or viscosity. Hence, they cannot yet predict accurately how local food webs will respond to anthropogenic pressures, notably to climate change and species invasions. Herein, we propose a framework that synthesises recent developments in food-web theory, integrating body size and metabolism with the physical properties of ecosystems. We advocate for combination of the movement paradigm with a modular definition of the predation sequence, because movement is central to predator-prey interactions, and a generic, modular model is needed to describe all the possible variation in predator-prey interactions. Pending sufficient empirical and theoretical knowledge, our framework will help predict the food-web impacts of well-studied physical factors, such as temperature and oxygen availability, as well as less commonly considered variables such as wind, turbidity or electrical conductivity. An improved predictive capability will facilitate a better understanding of ecosystem responses to a changing world.

The impact of practice on the adjustment of interaural cues in a lateralization task.

Lang and Buchner [J. Acoust. Soc. Am. 124, 3120-3131 (2008)] conducted trading experiments showing that the phenomenon of different trading ratios depending on which cue is adjusted by the listener is independent of the presentation of an explicit reference tone. Four experiments were conducted to test whether implicit reference tones during the preceding practice phase may have caused the different trading ratios. The results of Lang and Buchner were replicated, showing that an implicit reference learned during the practice phase cannot account for different trading ratios in experiments without the presentation of a reference tone.

Promoting resilience of large international collaborative research programs in times of global crisis.

The recent coronavirus disease (COVID-19) is impacting the research community worldwide with unforeseen long-term consequences for research, doctoral training, and international collaboration. It is already clear that the immediate effects of the crisis resulting from disrupted research stays and reduced career development opportunities are being most detrimental to early-career researchers. Based on a Sino-German international research training group dedicated to doctoral training and biodiversity-ecosystem functioning research, we show how resilience of large collaborative research programs can be promoted in times of global crisis. We outline possible adaptations in the areas of funding, research, teaching and learning, supervision and mentoring, and international collaboration helping to reduce detrimental impact for early-career researchers and to permanently strengthen the performance of large collaborative research groups in the postpandemic era.

Relative influence of interaural time and intensity differences on lateralization is modulated by attention to one or the other cue: 500-Hz sine tones.

When interaural time differences and interaural intensity differences are set into opposition, the measured trading ratio depends on which cue is adjusted by the listener. In an earlier article [Lang, A.-G., and Buchner, A., J. Acoust. Soc. Am. 124, 3120-3131 (2008)], four experiments showed that the perceived localization of a broad band sound for which differences in one cue were compensated by differences in the other cue such that the sound seemed to originate from a central position shifted back toward the location from which the sound appeared to originate before the adjustment. It was argued that attention shifted toward the effect of the to-be-adjusted cue during the compensation task, leading to an increased weighting of the to-be-adjusted cue. The use of broadband stimuli raises the question whether the "shift-back effect" was caused by attentional shifts to the effect of the to-be-adjusted binaural cue or by attention shifts to the particular frequency range which is most important for localizations based on the to-be-adjusted cue. Two experiments are reported in which sine tones of 500 Hz were used instead of broadband sounds. The shift-back effect could still be observed, supporting our original hypothesis. A control experiment showed that participants had accurate representations of the critical central position.

Statistical power analyses using G*Power 3.1: tests for correlation and regression analyses.

G*Power is a free power analysis program for a variety of statistical tests. We present extensions and improvements of the version introduced by Faul, Erdfelder, Lang, and Buchner (2007) in the domain of correlation and regression analyses. In the new version, we have added procedures to analyze the power of tests based on (1) single-sample tetrachoric correlations, (2) comparisons of dependent correlations, (3) bivariate linear regression, (4) multiple linear regression based on the random predictor model, (5) logistic regression, and (6) Poisson regression. We describe these new features and provide a brief introduction to their scope and handling.

Reassessing the token set size effect on serial recall: Implications for theories of auditory distraction.

Sequences of auditory objects such as one-syllable words or brief sounds disrupt serial recall of visually presented targets even when the auditory objects are completely irrelevant for the task at hand. The token set size effect is a label for the claim that disruption increases only when moving from a 1-token distractor sequence (e.g., "AAAAAAAA") to a token set size of 2 (e.g., "ABABABAB") but remains constant when moving from a token set size of 2 to a larger token set size (e.g., "ABCABCAB" or "DAGCFBEH"). Here we show that this claim was incorrect and based on experiments with insufficient statistical power. With sufficient statistical power it can be shown that disruption increases not only when the distractor token set size increases from 1 to 2, but also when it increases from two to eight one-syllable words (Experiment 1) and brief instrumental sounds (Experiment 2). These findings have implications for theories of auditory distraction which differ in their predictions about whether the distractor-induced performance decrement should (a) only be determined by acoustic differences between immediately adjacent distractor tokens (duplex-mechanism account) or (b) gradually increase as a function of the variability in the distractor set (attentional account). The present data are inconsistent with the duplex-mechanism account and support the attentional account. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Distraction by steady-state sounds: Evidence for a graded attentional model of auditory distraction.

Sound disrupts short-term retention in working memory even when the sound is completely irrelevant and has to be ignored. The dominant view in the literature is that this type of disruption is essentially limited to so-called changing-state distractor sequences with acoustic changes between successive distractor objects (e.g., "ABABABAB") and does not occur with so-called steady-state distractor sequences that are composed of a single repeated distractor object (e.g., "AAAAAAAA"). Here we show that this view can no longer be maintained. What is more, disruption by steady-state distractors is significantly reduced after preexposure to the distractor item, directly confirming a central assumption of attentional explanations of auditory distraction and parallel to what has been shown earlier for changing-state sounds. Taken together, the findings reported here are compatible with a graded attentional account of auditory disruption, and they are incompatible with the duplex-mechanism account. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Relative influence of interaural time and intensity differences on lateralization is modulated by attention to one or the other cue.

When setting interaural time differences and interaural intensity differences into opposition the measured trading ratio depends on which of the cues is adjusted by the listener. This paper provides some evidence that the different trading ratios may be an effect of a shift of attention toward the to-be-adjusted cue. The experiments consisted of two phases. In the compensation phase, participants canceled out the effect of one preset binaural cue by adjusting a compensatory value of the other cue until the sound was located in the center. In the localization phase participants assessed the virtual location of the sounds, again using the preset values of the fixed cue, but using the values of the other cue as previously adjusted. The sounds were no longer perceived as originating from the center. Instead, their perceived location was shifted back toward the location from which they appeared to originate before the adjustment. These findings suggest that during the compensation task the to-be-adjusted sound localization cue received an increased weight compared to the other cue. We propose shifts of attention between the cues as a mechanism that could account for this finding.

G*Power 3: a flexible statistical power analysis program for the social, behavioral, and biomedical sciences.

G*Power (Erdfelder, Faul, & Buchner, 1996) was designed as a general stand-alone power analysis program for statistical tests commonly used in social and behavioral research. G*Power 3 is a major extension of, and improvement over, the previous versions. It runs on widely used computer platforms (i.e., Windows XP, Windows Vista, and Mac OS X 10.4) and covers many different statistical tests of the t, F, and chi2 test families. In addition, it includes power analyses for z tests and some exact tests. G*Power 3 provides improved effect size calculators and graphic options, supports both distribution-based and design-based input modes, and offers all types of power analyses in which users might be interested. Like its predecessors, G*Power 3 is free.