Editorial: Woody plants and forest ecosystems in a complex world—Ecological interactions and physiological functioning above and below ground

International audienc

Animal biotelemetry / The impact of shape and attachment position of biologging devices in Northern Bald Ibises

Background: The impact of biologging devices on the aerodynamics or hydrodynamics of animals is still poorly understood. This stands in marked contrast to the ever more extensive use of such technologies in wild-living animals. Recently, increasing concerns have been raised about the impairing effects of these devices on the animals concerned. In the early days of biotelemetry, attention was focused solely on reducing weight, but now aerodynamic effects are also increasingly being considered. To investigate these effects, we trained Northern Bald Ibises to fly in a wind tunnel in which we measured heart rate and dynamic body acceleration (VeDBA) as proxies for energy expenditure in relation to different logger shapes and wind flow directions. Results: Our data provide evidence that the position of biologging devices significantly influence the flight distances, and the shape of biologging devices has a considerable effect on heart rate and VeDBA, both of which have been used as proxies for energy expenditure. Unfavorable shape and positioning go beyond merely affecting the effort required during flapping flight. The energetically probably more important effect is that the devices impair the bird’s ability to glide or soar and thus force them to perform the energetically much more demanding flapping flight more frequently. This effect was more pronounced in rising air than in horizontal airflow. A complementary study with wild Northern Bald Ibises during spring migration provides evidence that the position of the devices on the bird’s back affects the length of the flight stages. Birds carrying the devices on the upper back, fixed by wing-loop harnesses, had significantly shorter flight stages compared to birds with a more caudally positioned device, fixed by leg-loop harnesses.Conclusion: The attachment of biologging devices on birds affects their performance and behavior and thus may influence their fitness and mortality. Our results show that detrimental effects can be reduced with relatively little effort, in particular through a strictly aerodynamic design of the housing and increased consideration of aerodynamics when attaching the device to the body. In birds, the attachment of biologging devices via leg loops to the lower back is clearly preferable to the common attachment via wing loops on the upper back, even if this affects the efficiency of the solar panels. Nevertheless, the importance of drag reduction may vary between systems, as the benefits of having a biologging devices close to the center of gravity may outweigh the increase in drag that this involves. Overall, more research is required in this field. This is both in the interest of animal welfare and of avoiding biasing the quality of the collected data.Ortal Mizrahy-Rewald, Herwig A. Grogger [und 6 weitere]Version of recor

A Mass Balance Approach to Identify and Compare Differential Routing of \u3csup\u3e13\u3c/sup\u3eC-Labeled Carbohydrates, Lipids, and Proteins In Vivo

All animals route assimilated nutrients to their tissues where they are used to support growth or are oxidized for energy. These nutrients are probably not allocated homogeneously among the various tissue and are more likely to be preferentially routed toward some tissues and away from others. Here we introduce an approach that allows researchers to identify and compare nutrient routing among different organs and tissues. We tested this approach by examining nutrient routing in birds. House sparrows Passer domesticus were fed a meal supplemented with one of seven 13C-labeled metabolic tracers representing three major classes of macronutrients, namely, carbohydrates, amino acids, and fatty acids. While these birds became postabsorptive (2 h after feeding), we quantified the isotopic enrichment of the lean and lipid fractions of several organs and tissues. We then compared the actual 13C enrichment of various tissue fractions with the predictions of our model to identify instances where nutrients were differentially routed and found that different classes of macronutrients are uniquely routed throughout the body. Recently ingested amino acids were preferentially routed to the lean fraction of the liver, whereas exogenous carbohydrates were routed to the brain and the lipid fraction of the liver. Fatty acids were definitively routed to the heart and the liver, although high levels of palmitic acid were also recovered in the adipose tissue. Tracers belonging to the same class of molecules were not always routed identically, illustrating how this technique is also suited to examine differences in nonoxidative fates of closely related molecules. Overall, this general approach allows researchers to test heretofore unexamined predictions about how animals allocate the nutrients they ingest

Using the Leiden Guidelines to address key issues in digitally derived evidence

The global developments have shown one thing clearly: there is a lack of guidance and clarity when it comes to using DDE in the courtroom. Due to the fast evolution of digital technology and the (often, by design) slow evolution of courts and tribunals, the treatment of DDE within and between national and international accountability fora suffers from an absence of uniformity at best, and a lack of any useful guidance at worst.  The Leiden Guidelines on the Use of Digitally Derived Evidence in International Criminal Courts and Tribunals (“The Leiden Guidelines”) were created to address this legal lacuna by examining the various ways in which DDE has been treated in international criminal law. The Guidelines identify overarching standards of treatment, derived from the jurisprudence of international criminal courts and tribunals (“ICCTs”), that practitioners should consider when collecting and tendering DDE. Exploring the Frontiers of International La

Phenotypic plasticity and water flux rates of Citrus root orders under salinity

Knowledge about the root system structure and the uptake efficiency of root orders is critical to understand the adaptive plasticity of plants towards salt stress. Thus, this study describes the phenological and physiological plasticity of Citrus volkameriana rootstocks under severe NaCl stress on the level of root orders. Phenotypic root traits known to influence uptake processes, for example frequency of root orders, specific root area, cortical thickness, and xylem traits, did not change homogeneously throughout the root system, but changes after 6 months under 90 mM NaCl stress were root order specific. Chloride accumulation significantly increased with decreasing root order, and the Cl− concentration in lower root orders exceeded those in leaves. Water flux densities of first-order roots decreased to <20% under salinity and did not recover after stress release. The water flux densities of higher root orders changed marginally under salinity and increased 2- to 6-fold in second and third root orders after short-term stress release. Changes in root order frequency, morphology, and anatomy indicate rapid and major modification of C. volkameriana root systems under salt stress. Reduced water uptake under salinity was related to changes of water flux densities among root orders and to reduced root surface areas. The importance of root orders for water uptake changed under salinity from root tips towards higher root orders. The root order-specific changes reflect differences in vulnerability (indicated by the salt accumulation) and ontogenetic status, and point to functional differences among root orders under high salinity

Semantic segmentation of plant roots from RGB (mini-) rhizotron images-generalisation potential and false positives of established methods and advanced deep-learning models

Background Manual analysis of (mini-)rhizotron (MR) images is tedious. Several methods have been proposed for semantic root segmentation based on homogeneous, single-source MR datasets. Recent advances in deep learning (DL) have enabled automated feature extraction, but comparisons of segmentation accuracy, false positives and transferability are virtually lacking. Here we compare six state-of-the-art methods and propose two improved DL models for semantic root segmentation using a large MR dataset with and without augmented data. We determine the performance of the methods on a homogeneous maize dataset, and a mixed dataset of > 8 species (mixtures), 6 soil types and 4 imaging systems. The generalisation potential of the derived DL models is determined on a distinct, unseen dataset. Results The best performance was achieved by the U-Net models; the more complex the encoder the better the accuracy and generalisation of the model. The heterogeneous mixed MR dataset was a particularly challenging for the non-U-Net techniques. Data augmentation enhanced model performance. We demonstrated the improved performance of deep meta-architectures and feature extractors, and a reduction in the number of false positives. Conclusions Although correction factors are still required to match human labelled root lengths, neural network architectures greatly reduce the time required to compute the root length. The more complex architectures illustrate how future improvements in root segmentation within MR images can be achieved, particularly reaching higher segmentation accuracies and model generalisation when analysing real-world datasets with artefacts-limiting the need for model retraining.O

Small energy benefits of in-wake flying in long-duration migratory flights

During long-distance migrations, some bird species make use of in-wake flying, which should allow them to profit from the upwash produced by another bird. While indirect evidence supports energy saving as the primary benefit of in-wake flying, measurements are still missing. We equipped migrating northern bald ibises (Geronticus eremita) with high-precision global navigation satellite system data loggers to track their position in the flock. We estimated birds’ energy expenditure through different proxies, namely dynamic body acceleration (DBA), heart rate and effective wingbeat frequency. During active flapping flight, DBA estimates dropped off when in-wake compared with when not-in-wake. In addition, effective wingbeat frequency decreased, suggesting an increased use of intermittent gliding flight during in-wake periods. Heart rate varied greatly among individuals, with a clear decrease during gliding—corroborating its energy-saving function. Furthermore, we found consistent proof for decreased heart rate during in-wake flying, by up to 4.2%. Hence, we have shown that flying in the wake of another individual reduces birds’ DBA, heart rate and effective wingbeat frequency, which could reflect reduced energy requirement