Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2019
Authors
Henning Horn Janka Dibdiakova Kim H. Esbensen A VestlundAbstract
No abstract has been registered
Authors
Ana de la Moneda Maria Dolores Carro Martin Riis Weisbjerg Michael Roleda Vibeke Lind Margarita Novoa-Garrido Eduarda Molina-AlcaideAbstract
No abstract has been registered
Abstract
Multi-temporal Sentinel 2 optical images and 3D photogrammetric point clouds can be combined to enhance the accuracy of timber volume models on large spatial scale. Information on the proportion of broadleaf and conifer trees improves timber volume models obtained from 3D photogrammetric point clouds. However, the broadleaf-conifer information cannot be obtained from photogrammetric point clouds alone. Furthermore, spectral information of aerial images is too inconsistent to be used for automatic broadleaf-conifer classification over larger areas. In this study we combined multi-temporal Sentinel 2 optical satellite images, 3D photogrammetric point clouds from digital aerial stereo photographs, and forest inventory plots representing an area of 35,751 km2 in south-west Germany for (1) modelling the percentage of broadleaf tree volume (BL%) using Sentinel 2 time series and (2) modelling timber volume per hectare using 3D photogrammetric point clouds. Forest inventory plots were surveyed in the same years and regions as stereo photographs were acquired (2013–2017), resulting in 11,554 plots. Sentinel 2 images from 2016 and 2017 were corrected for topographic and atmospheric influences and combined with the same forest inventory plots. Spectral variables from corrected multi-temporal Sentinel 2 images were calculated, and Support VectorMachine (SVM) regressions were fitted for each Sentinel 2 scene estimating the BL% for corresponding inventory plots. Variables from the photogrammetric point clouds were calculated for each inventory plot and a non-linear regression model predicting timber volume per hectare was fitted. Each SVMregression and the timber volume model were evaluated using ten-fold cross-validation (CV). The SVMregression models estimating the BL% per Sentinel 2 scene achieved overall accuracies of 68%–75% and a Root Mean Squared Error (RMSE) of 21.5–26.1. The timber volumemodel showed a RMSE% of 31.7%, amean bias of 0.2%, and a pseudo-R2 of 0.64. Application of the SVMregressions on Sentinel 2 scenes covering the state of Baden-Württemberg resulted in predictions of broadleaf tree percentages for the entire state. These predicted values were used as additional predictor in the timber volume model, allowing for predictions of timber volume for the same area. Spatially high-resolution information about growing stock is of great practical relevance for forest management planning, especially when the timber volume of a smaller unit is of interest, for example of a forest stand or a forest districtwhere not enough terrestrial inventory plots are available to make reliable estimations. Here, predictions from remote-sensing based models can be used. Furthermore, information about broadleaf and conifer trees improves timber volume models and reduces model errors and, thereby, prediction uncertainties.
Authors
Katharina Strobl Christoph Moning Johannes KollmannAbstract
Drainage and afforestation of peatlands cause extensive habitat degradation and species losses. Restoration supports peatland biodiversity by creating suitable habitat conditions, including stable high water tables. However, colonization by characteristic species can take decades or even fail. Peatland recovery is often monitored shortly after restoration, but initial trends may not continue, and results might differ among taxonomic groups. This study analyzes trends in plant, dragonfly, and butterfly diversity within 18 years after rewetting of montane peatlands in central Germany. We compared diversity and species composition of 19 restored sites with three drained peatlands and one near‐natural reference site. Restoration resulted in improved habitat conditions and benefited species diversity, but there were marked differences among taxonomic groups. Dragonflies rapidly colonized small water bodies but their diversity did not further increase in older restoration sites. Characteristic peatland vegetation recovered slowly, since it depended on a high water holding capacity that was only reached after peat started accumulating. Generally, plant diversity developed toward reference conditions albeit incompletely, even 18 years after restoration. Butterflies responded less to peatland restoration; generalists increased only temporarily and specialists could not establish. In conclusion, peatland restoration improves habitat conditions and biodiversity, while trajectories of recovery are nonlinear and incomplete after two decades. This highlights the need for long‐term monitoring and a strategic selection of indicator species for evaluation of restoration success.
Authors
Wiktoria Kaczmarek-Derda Marit Helgheim Jan Netland Hugh Riley Kjell Wærnhus Samson Øpstad Liv Østrem Lars Olav BrandsæterAbstract
No abstract has been registered
Authors
B. S. Steidinger T. W. Crowther J. Liang M. E. Van Nuland G. D. A. Werner P. B. Reich G. J. Nabuurs S. de-Miguel M. Zhou N. Picard B. Herault X. Zhao C. Zhang D. Routh Meinrad Abegg C. Yves Adou Yao Giorgio Alberti Angelica Almeyda Zambrano Esteban Alvarez-Davila Patricia Alvarez-Loayza Luciana F. Alves Christian Ammer Clara Antón-Fernández Alejandro Araujo-Murakami Luzmila Arroyo Valerio Avitabile Gerardo Aymard Timothy Baker Radomir Bałazy Olaf Bánki Jorcely Barroso Meredith Bastian Jean-Francois Bastin Luca Birigazzi Philippe Birnbaum Robert Bitariho Pascal Boeckx Frans Bongers Olivier Bouriaud Pedro H. S. Brancalion Susanne Brandl Francis Q. Brearley Roel Brienen Eben Broadbent Helge Bruelheide Filippo Bussotti Roberto Cazzolla Gatti Ricardo Cesar Goran Cesljar Robin Chazdon Han Y. H. Chen Douglas Sheil K. G. PeayAbstract
The identity of the dominant root-associated microbial symbionts in a forest determines the ability of trees to access limiting nutrients from atmospheric or soil pools1,2, sequester carbon3,4 and withstand the effects of climate change5,6. Characterizing the global distribution of these symbioses and identifying the factors that control this distribution are thus integral to understanding the present and future functioning of forest ecosystems. Here we generate a spatially explicit global map of the symbiotic status of forests, using a database of over 1.1 million forest inventory plots that collectively contain over 28,000 tree species. Our analyses indicate that climate variables—in particular, climatically controlled variation in the rate of decomposition—are the primary drivers of the global distribution of major symbioses. We estimate that ectomycorrhizal trees, which represent only 2% of all plant species7, constitute approximately 60% of tree stems on Earth. Ectomycorrhizal symbiosis dominates forests in which seasonally cold and dry climates inhibit decomposition, and is the predominant form of symbiosis at high latitudes and elevation. By contrast, arbuscular mycorrhizal trees dominate in aseasonal, warm tropical forests, and occur with ectomycorrhizal trees in temperate biomes in which seasonally warm-and-wet climates enhance decomposition. Continental transitions between forests dominated by ectomycorrhizal or arbuscular mycorrhizal trees occur relatively abruptly along climate-driven decomposition gradients; these transitions are probably caused by positive feedback effects between plants and microorganisms. Symbiotic nitrogen fixers—which are insensitive to climatic controls on decomposition (compared with mycorrhizal fungi)—are most abundant in arid biomes with alkaline soils and high maximum temperatures. The climatically driven global symbiosis gradient that we document provides a spatially explicit quantitative understanding of microbial symbioses at the global scale, and demonstrates the critical role of microbial mutualisms in shaping the distribution of plant species.
Authors
Jari Vauhkonen Ambros Berger Thomas Gschwantner Klemens Schadauer Philippe Lejeune Jérôme Perin Mikhail Pitchugin Radim Adolt Miroslav Zeman Vivian Kvist Johannsen Sebastian Kepfer-Rojas Allan Sims Claire Bastick François Morneau Antoine Colin Susann Bender Pál Kovácsevics György Solti László Kolozs Dóra Nagy Kinga Nagy Mark Twomey John Redmond Patrizia Gasparini Monica Notarangelo Maria Rizzo Kristaps Makovskis Andis Lazdins Ainars Lupikis Gintaras Kulbokas Clara Antón-Fernández Francisco Castro Rego Leónia Nunes Gheorghe Marin Catalin Calota Damjan Pantić Dragan Borota Joerg Roessiger Michal Bosela Vladimír Šebeň Mitja Skudnik Patricia Adame Iciar Alberdi Isabel Cañellas Torgny Lind Renats Trubins Esther Thürig Golo Stadelmann Ben Ditchburn David Ross Justin Gilbert Lesley Halsall Markus Lier Tuula PackalenAbstract
No abstract has been registered
Authors
Min-Rui Wang Zhibo Hamborg Jiří Zámečník Alois Bilavčík Dag-Ragnar Blystad Sissel Haugslien Qiao-Chun WangAbstract
The present study described a droplet-vitrification cryopreservation for shoot tips of shallot (Allium cepa var. aggregatum), a small bulb onion. Shoot tips taken from in vitro stock shoots were precultured with 0.3 M and 0.5 M of sucrose, with 1 day for each concentration. Precultured shoot tips were treated with a loading solution containing 2 M glycerol and 0.6 M sucrose for 20 min and then exposed to plant vitrification solution 3 (PVS3) at 24 °C for 3 h of dehydration. Following exposure to PVS3, shoot tips were moved onto 5.0 μl PVS3 droplets on aluminum foil strips, followed by direct immersion into liquid nitrogen for 1 h. Frozen shoot tips were thawed by incubation in liquid MS medium containing 1.2 m sucrose for 20 min at room temperature, and then post-thaw cultured for shoot regrowth. Exposure of the shoot tips to PVS3 produced shoot regrowth (58%). Differential scanning calorimetry (DSC) detected 1.8% of freezable water in the shoot tips that had been dehydrated by PVS2, and no freezable water in those by PVS3 treatment. Exposure to PVS3 provided a broader safe temperature range (− 196 °C to − 88 °C), compared to that (− 196 °C to − 116 °C) of PVS2, for cryopreserved samples. Histological observations found that PVS3 dehydration allowed many cells in the apical dome and in the leaf primordia to survive following freezing in LN, while PVS2 dehydration resulted in much fewer surviving cells in the apical dome. The droplet-vitrification cryopreservation produced 56%, 72% and 32% shoot regrowth in cryopreserved shoot tips taken from in vitro shoots, adventitious buds regenerated from stem discs and field-grown bulbs, respectively. Advantages and disadvantages of the use of different source explants for cryopreservation were discussed. The droplet-vitrification cryopreservation produced 45% and 70% shoot regrowth in the additional two shallot genotypes ‘Kverve’ and ‘Lunteviga’. The results obtained in this study provide technical supports for setting-up cryo-bankings of genetic resources of shallots and other Allium species.
Abstract
No abstract has been registered
Abstract
No abstract has been registered