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Uncertainty of Future Forest Development with Special Regard to Site and Survivability of Scots pine (Pinus sylvestris L.) in Northern Germany
No full textWaldklimafonds unter Aufsicht der Bundesministerien für Ernährung und Landwirtschaft sowie für Umwelt, Naturschutz, nukleare Sicherheit und Verbraucherschutz aufgrund eines Beschlusses des Deutschen BundestagsDie Wald-Kiefer (Pinus sylvestris L.) ist die hinsichtlich Anbaufläche und erwarteter Trockenstresstoleranz bedeutendste Baumart Norddeutschlands. Typisch sind wenig durchmischte, störungsanfällige Bestände im Alter von etwa 75 Jahren. Vor dem Hintergrund des Klimawandels und einer unausgewogenen Altersstruktur stellt sich die Frage, wie die Bewirtschaftung von Kiefernwäldern ökologisch und ökonomisch weiterentwickelt werden kann, um ihre Funktionalität zu erhalten. Diese Arbeit untersucht die zukünftige Entwicklung von Kiefernwäldern unter verschiedenen realitätsnahen Bewirtschaftungs- und Klimaszenarien mit Fokus auf Standortbedingungen und Sterblichkeitsprozesse. Ziel ist es, die Bandbreite möglicher Entwicklungsgänge aufzuzeigen, bestehende Unsicherheiten zu quantifizieren und waldbauliche Handlungsempfehlungen zur Ernte und Anbaueignung unter dynamischen Umweltbedingungen abzuleiten.
Thematische Schwerpunkte liegen in der Analyse von Ursache-Wirkungs-Zusammenhängen sowie der Entwicklung eines Ziel-Mittel-Systems für die Waldentwicklung unter Unsicherheit. Dabei werden für Nordwest- und Nordostdeutschland differenzierte, ertragskundlich und waldbaulich relevante Einflussgrößen auf den naturnahen Waldumbau simuliert – jeweils unter Einbeziehung und Ausschluss von Störungen. Ergänzend erfolgt eine Modellierung von Störungsschweregraden in nordwestdeutschen Kiefernwäldern. Zur prioritären Umsetzung waldbaulicher Anpassungsmaßnahmen wird ein multikriterielles Entscheidungsunterstützungssystem entwickelt, das sich auf die Landschaftsebene fokussiert.
Basierend auf Daten der dritten Bundeswaldinventur wurden acht forstliche Bewirtschaftungsszenarien für einen Zeitraum von 50 Jahren auf Einzelbaumbasis simuliert. In vier ungestörten standort- und klimasensitiven Szenarien erfolgt die Auswahl von Waldentwicklungstypen mit dem Ziel, entweder hohe oder niedrige Kiefernanteile zu fördern. In einer anschließenden Monte-Carlo-Simulation wurden für die Szenarien mit hohem Kiefernanteil vier weitere Störungsszenarien mit verschiedenen Schweregraden definiert, die diskrete Bestandes- und diffuse Einzelbaumschäden kontrastieren. Anhand eines gleitenden Fensters von Klimadaten wird prognostiziert, dass sich die Sterblichkeit je nach Baumart zukünftig verdoppeln könnte. Durch die Gegenüberstellung unterschiedlicher Bewirtschaftungs- und Störungsszenarien wurde sowohl die Bandbreite möglicher Entwicklungen als auch das Ausmaß der Unsicherheit abgeschätzt.
Die Ergebnisse zeigen, dass die Anbauflächen und die Vorräte der Kiefer selbst unter fördernder Bewirtschaftung zurückgehen könnten. Dabei steigen die Starkholzvorräte und Nutzungsmengen sowohl mit als auch ohne Störungseinfluss. Die Waldentwicklung wird stärker von der Wahl der Waldbauziele und -verfahren, als von der Wahl der Klimamodelle beeinflusst. Die Waldumbaurate variiert bei ausgeprägten Reinbeständen zwischen 50 und 72 %; maßgeblich abhängig vom Durchforstungsregime sowie vom Zeitpunkt und Turnus der Ernte. Diskrete, hohe Schweregrade neigen dazu, den Waldumbau gemäß den Modellannahmen zu beschleunigen. Angesichts des gegenwärtig hohen Anteils alter Kiefernbestände erfolgt der Waldumbau insgesamt zu langsam und zu wenig differenziert, um den Herausforderungen des fortschreitenden Klimawandels und der unausgewogenen Altersstruktur angemessen zu begegnen.
Untersucht wurde ferner, welche Störungsfaktoren die Mortalität von Kiefern beeinflussen und ob sich daraus Schweregrade modellieren lassen. Diese Analyse basiert auf Massenerfassungen im staatlichen Waldschutz-Meldeportal, die mit Forsteinrichtungs- und Wetterdaten verknüpft wurden. Die Ergebnisse zeigen, dass diffuse Störungen mit niedrigen Schweregraden über einen Zeitraum von zehn Jahren am häufigsten auftreten und meist durch Wind ausgelöst werden. Die durchschnittliche Schadfläche beträgt 0,5 ha und die mediane Fläche liegt bei 0,12 ha. Biotische Störungsfaktoren verursachen im Vergleich zu abiotischen Faktoren höhere Schweregrade und nehmen zu. Der Schweregrad von Störungen in Kiefernwäldern wird besonders effektstark durch Konkurrenzverhältnisse, abgebildet durch den Mischungsanteil, sowie die Wasserverfügbarkeit beeinflusst. Insbesondere weisen Kiefern auf trockenen Standorten die stärksten Schäden auf. Es zeigt sich jedoch die Tendenz, dass die Schweregrade mit zunehmender Standortsgüte wieder ansteigen, wenn gleichzeitig die Baumartenvielfalt hoch ist. Die verwendete bayesianische Beta-Regression erreicht eine Erklärungskraft von 38 %.
Im Fallbeispiel des Landkreises Lüchow-Dannenberg dienen die vielfältigen Standorts- und Bestockungsattribute auf Landschaftsebene als Grundlage zur Priorisierung eines besitzübergreifenden Waldumbaus. Mithilfe einer multikriteriellen Entscheidungsanalyse wurden Fernerkundungs- und Feldbeobachtungsdaten genutzt, um die Baumartenvielfalt im Oberstand und deren Trockenstresstoleranz zu bewerten. Durch Gleichgewichtung der Indikatoren ergibt sich eine differenzierte Reihenfolge, die die bislang monokriterielle Erntedefinition anhand eines Zieldurchmessers ergänzen kann.
Die Arbeit betont die Bedeutung evidenzbasierter Entschei-dungsinstrumente für eine resiliente Waldentwicklung und unterstreicht die Notwendigkeit, die Waldbau-Richtlinien weiterzuentwickeln. Insbesondere kombinierte, ungleichmäßige Verjüngungsformen eignen sich, das natürliche Störungsregime der Kiefer in Norddeutschland nachzubilden. Für das Erreichen naturnaher Zielstellungen ist der Umgang mit dem Nebenbestand zentral, wofür Überhälter – durch früheren Erntebeginn als bisher – langfristig und in ausreichender Dichte ausreifen sollten. Die Ernteabfolge sollte durch eine multikriterielle Priorisierung auf Landschaftsebene und durch einen Zielstärkenrahmen ausgestaltet werden.
Die zielgerichtete Waldentwicklung wird voraussichtlich weniger durch statische Planungen gelingen, sondern vielmehr durch dynamische Anpassungsprozesse. Vor dem Hintergrund der klimawandelbedingten Unsicherheit erscheint die Praktizierung einer Vielfalt an kombinierten Waldbauverfahren als ein geeigneter Ansatz, um differenziert auf unbekannte Herausforderungen reagieren zu können.Scots pine (Pinus sylvestris L.) is the most important tree species in northern Germany in terms of both area of cultivation and expected tolerance to drought stress. It typically occurs in poorly mixed, disturbance-prone stands that are around 75 years old. Against the backdrop of climate change and an imbalanced age structure, the question arises of how pine forest management can be further developed in ecological and economic terms to ensure long-term functionality and viability. This study investigates the future development of Scots pine forests under different realistic forest management and climate scenarios, with a particular focus on site conditions and survivability. The aim is to illustrate the range of potential development trajectories, to quantify associated uncertainties, and to derive silvicultural recommendations for an adaptation to dynamic environmental conditions.
The research focuses on analyzing cause-effect relationships and developing a goal-means framework for forest development under uncertainty. Simulations were conducted for northwestern and northeastern Germany, regionally differentiated, in terms of yield sciences and silviculture significant drivers of forest restoration, both with and without disturbance impact. Additionally, the severity of disturbances in northwestern pine forests was modeled. To support the prioritization of silvicultural adaptation measures, a multi-criteria decision support system was developed that emphasizes the landscape level scale.
Based on data from the third National Forest Inventory, eight forest management scenarios were simulated over a 50-year period at the single-tree level. In four site-specific and climate-sensitive scenarios without disturbance impact, forest development types were selected to promote either high or low stand mixture proportions of Scots pine. In a subsequent Monte Carlo simulation, four disturbance scenarios with varying severity levels were applied to the high-pine proportion scenarios. These scenarios contrast discrete, stand-wise disturbances with diffuse, tree-wise damage. Using a moving window approach of climate data, mortality was projected to potentially double in the future, depending on the tree species. By comparing the different management and disturbance scenarios, both the range of possible developments and the range of uncertainty were estimated.
The results suggest that both the area of cultivation and growing stock of Scots pine could decline even under management practices designed to support the species. However, the stock of large-dimensioned timber and the amount of harvest increase under both disturbance severity scenarios. Forest development is more strongly influenced by silvicultural objectives and practices than by the choice of climate model. In monospecific stands, the forest landscape restoration rate ranges from 50 % to 72 %, largely depending on thinning intensity, as well as starting time and cycles of harvests. High-severity, discrete disturbances were found to accelerate forest restoration under the model assumptions. Given the currently high proportion of mature pine stands, the restoration rate is too slow and lacks sufficient differentiation to meet the challenges posed by climate change and the imbalance of the age structure.
The study further investigated which disturbance factors influence Scots pine mortality and whether a severity can be modeled accordingly. This analysis was based on crowd sensing data from the governmental forest health notification portal, which was linked with forest management plans and weather data. The findings show that diffuse, low-severity disturbances are the most frequent over a ten-year period and are mainly triggered by wind. The average disturbance size covers 0.5 ha, with a median of 0.12 ha. Biotic disturbance factors cause higher severity than abiotic ones and are increasing in frequency. The severity of disturbances in Scots pine forests is strongly influenced by competitive pressure, as indicated by pine’s volume mixture ratio, as well as by site water availability. Particularly severe damage occurs on dry sites, although severity tends to rise again under favorable growing conditions. The Bayesian beta regression applied in this study achieves an explanatory power of 38 %.
In the case study of the Lüchow-Dannenberg county, diverse site and stocking conditions at the landscape level scale were used to prioritize forest restoration across ownership boundaries. A multi-criteria decision analysis was conducted using remote sensing and field observation data to assess overstory tree species diversity and their tolerance to drought stress. Equal weighing of indicators produced a differentiated prioritization sequence, supplementing the previously monocriterial harvest definition based on target diameter.
This work emphasizes the importance of evidence-based decision tools for fostering resilient forest development and highlights the need to revise existing silvicultural guidelines. In particular, uneven-aged and combined regeneration systems are suitable for emulating the natural disturbance regime of Scots pine in northern Germany. For achieving close-to-nature goals, the treatment of the subsidiary stand is substantial: To this end, reserves should be retained at sufficient densities and the initiation of harvests in the main stand should begin earlier than has been common practice. Harvesting sequences should be guided by multi-criteria prioritization at the landscape level and by a framework of target diameters.
Overall, the intended forest development is less likely to succeed through static planning alone and will increasingly depend on dynamic adaptation processes. In light of uncertainty associated with climate change, the application of diverse silvicultural strategies represents a promising approach for responding flexibly and effectively to unforeseen challenges for Scots pine survivability.2025-11-2
Monitoring of Fusarium species on oats in Germany - identification, mycotoxin production and cultivar effects
No full textAufgrund seiner ernährungsphysiologischen Vorzüglichkeit und der anhaltenden Nachfrage
ist der Haferanbau in Deutschland in den letzten Jahren kontinuierlich angestiegen.
Allerdings gab es zur gleichen Zeit immer wieder Berichte über die Kontamination von
Erntegut mit Mykotoxinen, hervorgerufen durch den Befall der Rispe mit Fusarium spp.. Um
die Bedeutung der Rispenfusariose für den deutschen Haferanbau zu bewerten, wurden in
der vorliegenden Studie im Rahmen eines dreijährigen Monitorings das Vorkommen und
die Zusammensetzung des Spektrums von Fusarium spp. und der assoziierten Mykotoxine
in deutschem Sommerhafer untersucht. Weiterhin wurde in der vorliegenden Arbeit die
Anfälligkeit ausgewählter Sorten gegenüber F. langsethiae und deren Reaktion auf die
Kontamination mit dem T-2-Toxin in vitro und in Feldversuchen untersucht.
Im Rahmen des Monitorings wurden von 2020 bis 2022 Ernteproben aus fungizid-freien
Parzellen der Hafersorten Max, Apollon und Lion von verschiedenen Standorten in
Deutschland gesammelt und auf den Befall mit Fusarium spp. untersucht. Dazu erfolgte die
Isolation und Identifikation von Fusarium spp. von infizierten Körnern, sowie die
Quantifizierung von Fusarium-DNA mittels qPCR. Zur Bewertung des Einflusses von
Umweltfaktoren und pflanzenbaulichen Praktiken auf die Befallsstärke, wurden zusätzlich
standortspezifische Daten zu Fruchtfolge, Niederschlag, Temperatur und relativer
Luftfeuchtigkeit erhoben. In den Jahren 2020 und 2022 konnte mit 11,4% und 12,8% nur
eine geringe Befallshäufigkeit mit Fusarium spp. festgestellt werden, während sie im Jahr
2021 auf 38,4% anstieg. Insgesamt konnten bis zu 17 verschiedene Fusarium-Arten von
Haferkörnern isoliert werden. Im Untersuchungszeitraum wurden F. poae, F. tricinctum und
F. avenaceum als vorherrschende Arten im deutschen Haferanbau festgestellt. Im
Gegensatz dazu konnten die Produzenten von Typ A oder Typ B Trichothecenen nur mit
geringerer Häufigkeit isoliert werden. Der molekulare Nachweis mittels qPCR-Analyse
zeigte ebenfalls das erhöhte Auftreten von F. poae und F. tricinctum in natürlich infizierten
Körnern. Während das hohe Vorkommen von F. avenaceum in den Ergebnissen der qPCR
nicht bestätigt werden konnte, wurde demgegenüber eine erhöhte Konzentration an
F. langsethiae-DNA in den Körnern nachgewiesen.
Die Analyse des Mykotoxinauftretens erfolgte mittels HPLC-MS/MS und bestätigte das
Vorkommen von DON, NIV, T-2 und HT-2 im deutschen Haferanbau. Die durchschnittlichen
Konzentrationen betrugen dabei 36,8 µg/kg für DON, 33,1 µg/kg für NIV, 31,0 µg/kg für T-2,
7,7 µg/kg für HT-2 und 38,7 µg/kg als Summe aus T-2+HT-2. Trotz durchschnittlich niedriger
Konzentrationen wurden gelegentlich erhöhte Gehalte von DON (max. 224,53 µg/kg) oder
T-2+HT-2 (max. 637,6 µg/kg) nachgewiesen. In keiner der untersuchten Proben wurden Konzentrationen für DON, T-2 und HT-2 nachgewiesen, die die geltenden gesetzlichen
Grenzwerte überschritten.
Die Ergebnisse des Monitorings zeigten starke jährliche Schwankungen in der
Befallshäufigkeit, der Zusammensetzung des Spektrums an Fusarium spp. und dem
Vorkommen von Mykotoxinen. Qualitative Veränderungen in der Zusammensetzung des
Fusarium-Artenspektrums traten dabei in Abhängigkeit von den jährlichen Schwankungen
der monatlichen Niederschlagsmenge und Durchschnittstemperatur auf. Jedoch konnten
nur geringe Korrelationen zwischen klimatischen Faktoren und der Höhe der pilzlichen DNA
einzelner Arten oder der Konzentration einzelner Mykotoxine ermittelt werden.
Die Ergebnisse zeigten zudem einen Einfluss der Vorfrüchte auf die DNA-Konzentrationen
von F. tricinctum und F. langsethiae. Höhere DNA-Gehalte beider Arten wurden in
Haferproben gemessen, die nach Sommer- und Wintergetreide angebaut wurden. Für
F. poae konnte hingegen kein signifikanter Effekt der Fruchtfolge auf den Gehalt an
pilzlicher DNA festgestellt werden. Höhere Konzentrationen von T-2 und HT-2 wurde nach
getreideartigen Vorfrüchten festgestellt werden, während signifikant höhere DON-Werte
nach getreidefreien Sommerungen gemessen werden konnten. Für die untersuchten
Sorten konnten keine signifikanten Unterschiede bezüglich der Befallshäufigkeit, der
Konzentration an pilzlicher DNA oder dem Mykotoxingehalt für die analysierten Fusarium
Arten nachgewiesen werden. Insgesamt zeigte das Monitoring ein geringeres Risiko für die
deutsche Haferproduktion auf, da die wichtigsten Fusarium spp. von geringerer
toxikologischer Relevanz sind und die nachgewiesenen Mykotoxinkonzentrationen niedrig
waren.
Zur Bewertung der Sortenresistenz gegenüber F. langsethiae wurden zwei Feldversuche
und eine Gewächshausstudie mit 32 Genotypen mit künstlicher Inokulation durchgeführt.
Sowohl bei den beiden Feldversuchen als auch bei der Gewächshausstudie konnten große
Unterschiede in der Konzentration der pilzliche DNA in den infizierten Kernen festgestellt
werden. In den Sorten Talkunar, KLAR185 und Apollon wurden in allen Umwelten die
niedrigsten Konzentrationen an F. langsethiae-DNA gemessen, während die Sorten Gabriel
und Magellan durchweg hohe DNA-Konzentrationen aufwiesen. Im Gegensatz dazu
konnten für die Sorten Karl, Simon und Dominik starke Unterschiede zwischen den
Umwelten beobachtet werden. Trotzdem konnten in einigen Sorten niedrige
Konzentrationen bzw. hohe Konzentrationen an F. langsethiae DNA in allen Umwelten
gemessen werden, während für andere Sorten starke Unterschiede zwischen den
Umwelten beobachtet werden konnte Die Interaktion verschiedener Sorten mit dem Mykotoxin T-2 wurde in mehreren in vitro
Experimenten deren Schwerpunkt auf der Aufnahme des Toxins durch die Pflanze lag
untersucht. Die Untersuchung wurde in zwei Ansätzen durchgeführt: der Kultivierung von
Keimlingen in einer T-2 haltigen Lösung und der Applikation von T-2 auf die Blätter von
Keimlingen. Zur Bewertung der Aufnahme wurden alle Proben mittels HPLC-MS/MS
analysiert. Die Ergebnisse zeigten, dass alle Sorten in der Lage waren, T-2 über Wurzeln
und Blätter aufzunehmen und zu HT-2 zu metabolisieren. Bei den Versuchen zur
Wurzelaufnahme zeigten die Sorten zudem nicht nur signifikante Unterschiede bei der
Aufnahme, sondern auch bei der Anreicherung von T-2 und HT-2 in der Pflanze. Ebenso
konnten nach der Behandlung der Blätter mit T-2 signifikante Unterschiede hinsichtlich der
Anreicherung von T-2 und HT-2 beobachtet werden. Nach beiden Behandlungen konnten
Sorten mit geringer Anreicherung von T-2 und HT-2 sowie mit hoher Anreicherung
identifiziert werden. Darüber hinaus unterschieden sich die Sorten erheblich hinsichtlich des
Verhältnisses von HT-2 zu T-2 in den analysierten Pflanzenteilen. Das größte Verhältnis
wurde bei der Sorte Symphony festgestellt, was auf eine höhere Umsatzrate von T-2 zu
HT-2 hinweist. Zudem konnten in den Keimlingen auch niedrige Konzentrationen an T-2
und HT-2 von im Mittel bis zu 0,1 µg/g in den Pflanzenorgane unterhalb des behandelten
Blattes nachgewiesen werden, was auf eine potenzielle Verlagerung der Mykotoxine durch
die Pflanze hindeutet. Weiterhin konnte in beiden Versuchen eine Ausscheidung von T-2
oder HT-2 über die Wurzeln von bis zu 1,55% der applizierten Menge beobachtet werden.
Insgesamt konnten mit beiden Methoden resistente oder tolerante Sorten identifiziert
werden, die zu einer geringeren Mykotoxinakkumulation in den Körnern beitragen können,
indem sie entweder eine geringere Akkumulation in den behandelten Organen oder höhere
Umsatzraten aufweisen
Die Behandlung der Blätter von Keimlingspflanzen mit 13C-markiertem T-2, sowie der
anschließenden Analyse mittels LC-QTOF zeigte, dass als wichtigster Metabolit von T-2
und HT-2 in Pflanzen HT-2-3-G nachgewiesen werden konnte. Nach der Behandlung der
Blätter mit T-2 konnte HT-2-3-G nicht nur in den behandelten Blättern nachgewiesen
werden, sondern auch im unbehandelten Stängel. Diese Beobachtung deutet ebenfalls auf
eine Translokation des Toxins in der Pflanze hin.
Die dargestellten Ergebnisse geben Einblicke in das Auftreten von Fusarium spp. und
assoziierter Mykotoxine im deutschen Haferanbau, sowie der potenziellen Bedrohung, die
sich daraus für die Sicherheit und Qualität von Lebensmitteln ergeben könnten. Die
gewonnenen Erkenntnisse können genutzt werden, um Strategien zur Minimierung des
Fusarium-Risikos für Landwirte und Züchter zu entwickeln. Die Ergebnisse zur Sortenresistenz gegenüber einer Infektion mit F. langsethiae und der Aufnahme von T-2
können in die künftige Züchtungsforschung einfließen.The use of oats in human nutrition has increased in recent years due to their beneficial
nutritional components. Nonetheless, with the implementation of new legal limits, elevated
levels of mycotoxins in the harvested material have become an issue of concern throughout
oat production in Europe. For this purpose, the occurrence and composition of the
Fusarium spp. spectrum and their associated mycotoxins in German spring oats were
determined over a three-year monitoring period in the present study. The investigation also
focused on analysing the susceptibility of selected cultivars to F. langsethiae and their
reaction to contamination with T-2 toxin in vitro and in field experiments.
Within the framework of the monitoring, samples were collected from fungicide-free plots of
the cultivars Max, Apollon and Lion at multiple locations across Germany from 2020 to 2022.
Samples were analysed by isolation and identification of Fusarium spp. and the detection
of Fusarium DNA by qPCR. For the evaluation of environmental factors and agronomic
practices, site-specific data concerning crop rotation, precipitation, temperature and relative
humidity were collected at each location. Low disease incidence was observed in 2020
(11,4%) and 2022 (12,8%), while the incidence in 2021 (38,4%) nearly tripled. In total, up
to 17 different Fusarium spp. were isolated from oat kernels. Throughout the monitoring
period, F. poae, F. tricinctum and F. avenaceum were found to be the prevalent species.
Important producers of type A or type B trichothecenes on the other hand were isolated with
a lower frequency. qPCR analysis further underlined the high presence of F. poae and
F. tricinctum in naturally infected kernels. While the high presence of F. avenaceum could
not be replicated, the qPCR analysis also revealed a frequent occurrence of F. langsethiae
DNA in infected kernels.
Mycotoxin analysis was performed using HPLC-MS/MS and confirmed the presence of
DON, NIV, T-2 and HT-2. Average concentrations during the monitoring period were
36.8 µg/kg for DON, 33.1 µg/kg for NIV, 31.0 µg/kg for T-2, 7.7 µg/kg for HT-2 and
38.7 µg/kg for the sum of T-2+HT-2. Despite low average concentrations, peak
concentrations of DON (max: 224.53 µg/kg) or the sum of T-2+HT-2 (max: 637.6 µg/kg)
were occasionally detected. In none of the analysed samples, DON, T-2 and HT-2 were
detected at concentrations above the current legal limits.
High annual variation in the disease incidence, the composition of the Fusarium spp.
spectrum and the occurrence of mycotoxins was observed throughout the monitoring
period. Qualitative alterations in the composition of the Fusarium species spectrum
coincided with annual environmental variation concerning precipitation and mean temperature. However, correlations between climatic variables and the level of fungal DNA or the concentrations of mycotoxins were rather low.
Concentrations of F. tricinctum and F. langsethiae DNA measured in infected kernels varied
significantly between different types of preceding crops. Higher concentrations were found
in oats grown after spring and winter cereals. No significant effect of crop rotation was found
for the levels of F. poae DNA. Similarly, higher concentrations of T-2 and HT-2 were found
when the previous crops were cereals, while significant higher DON concentrations were
detected after non-cereal spring crops. The examined cultivars did not show any significant
differences regarding disease incidence, concentration of fungal DNA or mycotoxin content
for any of the analysed Fusarium spp.. All in all, the monitoring revealed a lower risk for
German oat production as the most frequent Fusarium spp. are of a lesser toxicological
relevance and detected mycotoxin concentrations were low.
Resistance to initial infection by F. langsethiae was examined in a set of 32 cultivars in two
field experiments and one greenhouse study. High variation of the concentration of fungal
DNA in infected kernels was observed between the two field trials as well as the greenhouse
study. Nonetheless, some cultivars accumulated consistently low, respectively high,
concentrations of fungal DNA across all environments, while others showed strong variation
between the examined environments. These results indicated that there are already more
resistant cultivars present on the German market.
The interaction of cultivars with the mycotoxin T-2 was evaluated in multiple in vitro
experiments focussing on the uptake of the toxin by roots and leaves of seedlings. Studies
were performed by cultivating seedlings in a solution containing T-2 or the treatment of
leaves with T-2. All samples were analysed using HPLC-MS/MS. Results revealed that all
cultivars were able to take up T-2 through roots and leaves and to metabolize it to HT-2. In
the root uptake experiments, cultivars showed significant differences concerning the uptake,
but also the accumulation of T-2 and HT-2 in the plant. Significant differences concerning
the accumulation of T-2 and HT-2 were also observed after treating leaves with T-2.
Following both treatments, cultivars with low accumulation of T-2 and HT-2 and high
accumulation could be observed.
Furthermore, cultivars varied significantly in the ratio of HT-2/T-2 detected in plants. The
highest ratio was found in the cultivar Symphony indicating a higher turnover rate of T-2 to
HT-2. In seedlings only treated on leaves, low concentrations of T-2 and HT-2 were also
detected in untreated plant parts up to 0.1 µg/g on average indicating that plants were able
to translocate the mycotoxins. Additionally, excretion of T-2 or HT-2 through the roots of up
to 1.55% of the applied amount was observed in both experiments with some variation between cultivars. Overall, both methodologies were able to identify resistant or tolerant
cultivars that are able to contribute to lower mycotoxin accumulation in kernels, by either
low accumulation in treated organs or higher turnover rates.
Mycotoxin analysis of plant material using LC-QTOF, following the treatment of leaves with
13C-labelled T-2, revealed that the major metabolite of T-2 in plants, besides HT-2, was
HT-2-3-G. After leaf treatment, HT-2-3-G was most not only abundant in the treated leaves,
but also the untreated stem, suggesting translocation.
The results of this study offer closer insights into the occurrence of Fusarium spp. and the
threat they may pose to oats produced in Germany through their ability to produce
mycotoxins. These findings can be used to design strategies to manage the risk of Fusarium
for farmers and breeders. The results on cultivar resistance to infection with F. langsethiae
and the uptake of T-2 could be incorporated into future breeding research.2025-11-1
Nonlinear Parsimonious Modeling with Information Filtering Networks: Theory and Practice
No full textThis thesis offers a comprehensive exploration and methodological advancement of Information Filtering Networks (IFNs), emphasizing Triangulated Maximally Filtered Graphs (TMFG), Local-Global (LoGo) models, and their nonlinear extensions. IFNs represent sparse, interpretable, and computationally efficient network structures designed to retain essential information from complex datasets by systematically filtering correlations and dependencies. The principal objective of this research is to develop, validate, and demonstrate robust IFN-based frameworks across diverse domains such as financial forecasting, clustering, and image processing, showcasing their broad applicability and methodological superiority relative to traditional modeling techniques.
Initially, the thesis addresses the challenges of information extraction from complex web structures through a novel hybrid web crawler that integrates dynamic and static crawling methods, enhanced by parallel computing techniques. This method significantly accelerates data extraction from online databases and websites requiring natural language processing techniques, achieving efficiency improvements of up to 100-fold compared to single conventional methods, thus providing a high-quality, large-scale financial data extraction approach essential for subsequent financial time series modeling.
Subsequently, using the acquired financial data, this research advances into financial forecasting through an advanced hybrid modeling framework. This approach combines Variational Mode Decomposition (VMD) for signal preprocessing, TMFG for feature selection, and Long Short-Term Memory (LSTM) networks for predictive modeling. TMFG systematically filters and selects structurally significant features, resulting in predictive models that achieve enhanced forecasting accuracy and interpretability. This hybrid model efficiently decomposes financial signals, reduces redundancy, and captures intrinsic data patterns, notably enhancing predictive accuracy and computational efficiency over traditional statistical and machine learning models.
Further contributions include integrating Grey Relational Analysis (GRA) with the LoGo framework, constructing localized sparse inverse covariance matrices for accurate short-term forecasting. Leveraging sparse precision matrices derived from IFNs, the LoGo model captures intricate global and local dependency structures. Combining GRA as a preprocessing and ranking mechanism significantly improves model robustness, especially within volatile financial environments.
To address theoretical limitations of linear correlation matrices, the thesis introduces nonlinear dependency transformation techniques for effectively modeling non-Gaussian and nonlinear relationships. Applying TMFG within this transformed space generates decomposable networks suited for constructing sparse, parsimonious models. This methodological innovation overcomes the limitations of conventional Pearson-based correlation approaches, enabling more accurate modeling of complex, non-normal datasets. It turns out that Gaussian-Copula transformation outperforms other normalization methods for its effectiveness in stabilizing data distributions, significantly enhancing the performance and accuracy of nonlinear LoGo models.
Building upon these developments, this thesis proposes a nonlinear parsimonious model integrating Gaussian-Copula transformations with the LoGo framework. This integration allows for a more accurate representation of nonlinear dependencies, facilitating the precise construction of sparse precision matrices from TMFG-generated decomposable networks. The proposed Copula–LoGo method significantly outperforms traditional models, such as Principal Components Analysis (PCA), Support Vector Machines (SVM), and standalone LSTM networks, in predictive accuracy and computational efficiency.
However, when applying the new nonlinear Copula–LoGo model, certain drawbacks are encountered, particularly errors arising during data transformation into Copula distributions. To address this issue, a novel classification-forecast methodology utilizing the Copula–LoGo model is proposed. This approach utilizes dynamic clustering to reveal hidden structural patterns within high-dimensional time series data, subsequently employing these patterns as contextual priors in nonlinear LoGo regression models. This integration significantly enhances model adaptability, particularly beneficial for datasets characterized by dynamic regime shifts.
Finally, the applicability of IFNs extends into image processing, proposing a TMFG-based framework for image segmentation and denoising. This model effectively captures spatial dependencies between pixel intensities and edge features, leveraging the sparse, planar structure of TMFG for computational efficiency and high-resolution feature preservation. This confirms the generalizability and efficacy of IFN methodologies beyond temporal data, highlighting their potential for spatial data analysis and computer vision.
Collectively, this thesis contributes a robust and versatile methodological framework centered around IFNs and LoGo models. It underscores the effectiveness and adaptability of TMFG and LoGo models as powerful tools for dependency modeling, forecasting, clustering, and spatial analysis. By advancing the core principles of sparsity, decomposability, and locality inherent to IFNs, the research presented herein lays a rigorous foundation for future developments in interpretable and computationally efficient modeling across various scientific and engineering domains.2025-11-1
Site-Selective C–H Activation for Small Molecules and π-Conjugated Polymers
No full textThe selective installation of organic fragments onto aromatic scaffolds remains a central challenge in organic synthesis. Due to growing concerns over resource depletion and environmental impact, chemists are increasingly striving not only to perform these reactions efficiently but also to render them more sustainable. In this regard, this thesis explores sustainable strategies that integrate cross-electrophile coupling and C–H activation through electrochemical or photochemical methodologies. First, a nickel-catalyzed electrochemical cross-electrophile coupling is presented. The reaction enables site-selective modification of non-prefunctionalized arenes through the formation of aryl sulfonium salts. Notably, one-pot electrocatalytic alkylations are viable, highlighting the user-friendly nature of the approach. Second, a low-temperature ruthenium-catalyzed C–H activation using ruthenium trichloride as a simple precatalyst is explored. The present ruthenium catalysis allows for ortho- or meta-functionalizations of diverse substrates, including pharmaceutical molecules and natural products. Electrochemical analysis supports a ruthenium(III/II) system through cathodic reduction. Third, a ruthenium-catalyzed C–H arylation polymerization proceeding at ambient temperature is showcased. The mild conditions are enabled by visible-light irradiation, affording polymers with narrow polydispersity and high chemoselectivity. Overall, these studies demonstrate how electrochemical and photochemical techniques can drive site-selective functionalizations in a sustainable manner, advancing the field of green organic synthesis.2025-11-2
Achieving Scalable AI Inference in a Unified Cloud and HPC Environment by Employing System of Systems Architecture Design
No full textProviding access to AI powered services commonly requires access to powerful compute infrastructure equipped with hardware accelerators such as GPUs. The recent rise of LLMs further emphasized this need and already caused many companies to invest in the construction of compute and data centers as well as the development of specialized AI hardware. Many HPC centers are equipped with GPUs but only support batch job orchestration and cannot deploy and expose AI models to provide AI-as-a-Service. Moreover, as AI models might be required to process sensitive and personal data, the platforms exposing them must be designed to handle said data with respect to the applicable privacy regulations, e.g., GDPR.
In this work we present two architecture designs of AI inference platforms that enable access to AI models deployed in an HPC environment. The designs preserve the batch job orchestration capabilities of the respective HPC environments while also adhering to privacy regulations. The two designs represent a cloud-native and an HPC-native approach, respectively. The first of the two designs is called Scalable Kubernetes Inference Platform (SKIP) and focuses on a cloud-native approach by building on Kubernetes and employing and configuring mature software products from the Kubernetes ecosystem.
The second design is called Scalable AI Accelerator (SAIA), which represents the HPC-native approach and builds on top of Slurm in the HPC-environments. In order to contrast the cloud-native and HPC-native approaches we systematically compared SKIP and SAIA to identify significant tradeoffs and limitations. Furthermore, as both designs consist of many subsequent systems, for instance, to handle the respective cloud and HPC environments, we developed a novel scientific workflow to design and validate System of Systems (SoS) architectures. This method enables the systematic design and evaluation of SoS architectures that internally consist of intermediate SoSs.2025-12-1
Designing a System for Tracking and Spatio-Temporal Action Classification of Primates
No full textPrimate researchers in both laboratory settings and natural environments are fundamentally interested in primate behavior. Approaches range from controlled laboratory setups enabling implant-based neuronal recordings to field studies observing natural individual and group behavior.
Recent advances in recording devices and computer vision have made it possible to automatically collect behavioral data at large scales. This includes highly calibrated static camera systems in the lab, as well as camera traps and handheld recordings in the wild, triggered automatically or operated manually.
The rapid increase in data volume renders manual analysis infeasible, while providing abundant training material for computer vision methods. This allows researchers to use data-driven approaches to efficiently detect and analyze behaviors in long video recordings or image sequences.
Given this complex video data, we present CNN-based methods for multi-animal multi-object tracking and spatio-temporal action detection of individual primates.
The overarching aim is to reduce manual annotation effort and support large-scale behavioral analysis by providing robust tools for tracking, identifying and classifying bodily actions, thereby enabling data-driven research in primatology and neuroscience.
Towards supporting automated primate behavior analysis, in this thesis we present two main contributions:
1. Tracking:
A multi-object tracker based on bounding boxes, adapted from the single-class pedestrian tracking architecture FairMOT, to track both primates and additional objects of interest. Bounding boxes can be annotated efficiently and generalize well across environments and primate species. Extending the tracker from single- to multi-class detection enables researchers to include other relevant objects --such as feeders or enrichment devices-- depending on the experimental setup. This supports richer behavioral analyses.
2. Action detection:
Multiple approaches for automatic action classification, building on the bounding box–based tracking:
(a) joint action detection within the tracking framework, offering an integrated end-to-end solution that is easy to use for behavioral researchers;
(b) a second-stage ResNet-based classifier operating on cropped primate detections, enabling flexible retraining for new action sets, eliminating the need to retrain the tracker;
(c) a lightweight and conceptually simple MLP-based model that predicts actions from time-series of bounding box traces across multiple camera perspectives, capturing movement dynamics over time.
We trained and evaluated our tracking and action classification methods on a dataset collected in the Exploration Room at the German Primate Center. The dataset focuses on on rhesus macaques (Macaca mulatta) engaging in a free-foraging experiment designed to encourage a wide range of full-body behaviors, while interacting with multiple objects of interest.
The adaptability of our tracking framework was further demonstrated by successfully applying a closely related variant --with modifications to the association strategy-- to recordings from the wild.
The architectures developed as part of this work are available at https://github.com/mnuske/PrEFairMOT.2025-12-1
Impacts of warmer temperatures on the above- and belowground system of four economically important timber species
No full textRecent decades of climate warming, along with more frequent heatwaves, have profoundly
affected European forests, causing vitality loss and increased mortality in many tree
species. Given the essential role forests play as carbon sinks in mitigating climate change,
it is crucial to deepen our understanding of species-specific responses to warming aiming
to inform forest management and preserve ecosystem functionality. While most existing
studies focus on the impacts of drought, there has been comparatively less attention on the
effects of elevated temperatures.
This thesis investigates how four major timber species—European beech (Fagus sylvatica),
sessile oak (Quercus petraea), Scots pine (Pinus sylvestris), and Douglas fir (Pseudotsuga
menziesii)—respond to a warmer climate. The study compares forest stands in two regions
of Germany, the northern German lowlands and the Upper Rhine Valley. In the Rhine
Valley, mean annual temperatures are approximately 2°C higher, reflecting conditions
expected in large parts of Germany by the middle to end of the century. The research
examines both aboveground growth using dendroecological methods and belowground
responses through analyses of fine root traits.
Radial growth data from the past three decades was analyzed to discern trends since the
significant onset of climate warming and to identify climatic variables that limit growth in
both study regions. Findings reveal that a higher mean annual temperature of 2°C, alongside
more frequent hot days, increases the sensitivity of beech and oak to water stress, while
conifers in both regions are sensitive. Moreover, Douglas fir and Scots pine exhibited a
stronger negative response to summer heat. Over recent decades, basal area increment
(BAI) has declined for Scots pine and Douglas fir across both regions. Beech exhibited
similar declines in the warmer Upper Rhine Valley, while oak showed a positive growth
trend. Negative pointer years were closely associated with dry conditions. Although a radial
growth decrease resulting from climatic stress was observed, all species recovered within
one to three years, which highlights their potential resilience to short-term climate
fluctuations.
Belowground responses were assessed through a fine root inventory and the use of ingrowth
cores. In the warmer region, fine root biomass was significantly lower for beech and
Douglas fir, while cumulative fine root surface area decreased for pine, Douglas fir, and
beech. Oak, however, remained unaffected. Root productivity and longevity also declined
for Douglas fir and pine in the warmer region, reflecting their vulnerability to warming.
Beech displayed a slight, non-significant reduction in productivity, but its root longevity
increased marginally. Oak, in contrast, demonstrated tendencies toward both increased
productivity and longevity, suggesting highest resilience across species. These findings
reveal significant differences in belowground vulnerability to warming among Central
Europe's major timber species in favor of broadleaved species.
The results emphasize the complex and species-specific responses of Central Europe's
major timber species to climate warming, emphasizing the importance of considering both
aboveground and belowground processes. The studies underscore the elevated vulnerability
of conifers compared to broadleaved species, with sessile oak standing out as the most
resilient. The findings align with previous research highlighting oak as a critical component
of future management strategies to promote forest resilience under climate change.
However, long-term effects of more frequent and severe heatwaves in combination with
droughts remain uncertain, emphasizing the need for further studies on physiological and
ecological mechanisms underlying the species-specific responses. This research provides
valuable insights that can are beneficial for adaptive management strategies in climate-
smart forestry. By integrating more heat- and drought-tolerant species, enhancing forest
structural diversity, and prioritizing site-specific approaches, we can improve forest
resilience and vitality, thus protecting their role as carbon sinks in a rapidly warming world.2025-12-2
Basement-Cover Relationships in the Dom Feliciano Belt
No full textDAAD, GoeLemDie Interaktion der Hauptkratone, die die heutige geologische Struktur Südamerikas und Afrikas prägen, zusammen mit mehreren kleineren Krustenblöcken, führte im späten Neoproterozoikum zur Bildung von Südwest-Gondwana. Dieser lang andauernde orogene Prozess wird als Afrikanisch–Brasilianische Orogenese bezeichnet. Im globalen Kontext ist die Entstehung Gondwanas das Ergebnis konvergenter Plattenbewegungen nach dem Zerfall des Superkontinents Rodinia im frühen Neoproterozoikum. Die Beteiligung vieler Krusteneinheiten aus dem südlichen Südamerika und Afrika an Rodinia ist jedoch umstritten. Daher spiegelt das geologische Archiv dieser Regionen nicht zwingend die Spaltung Rodinias wider. In diesem Zusammenhang kommt tonischen Gesteinseinheiten in West-Gondwana eine strategische rolle bei der Rekonstruktion des Übergangs vom Zerfall Rodinias zur Entstehung Gondwanas zu.
Diese Studie präsentiert neue geologische, petrologische und geochronologische Daten aus dem südamerikanischen Dom-Feliciano-Gürtel, der im Zuge der Wechselwirkungen zwischen dem Kongo-, dem Río-de-la-Plata- und dem Kalahari-Kraton entstand. Die Ergebnisse verfeinern unser Verständnis der tonisch-kryogenischen Entwicklung dieses Gürtels und erweitern es insbesondere in Bezug auf das orogene Grundgebirge und die zugehörigen Deckserien. Darüber hinaus liefern sie neue Hinweise auf eine prä-kollisionale tektonische Verbindung mit dem Kaoko-Gürtel im südwestlichen Afrika.
Die Entwicklung des östlichen Abschnitts des Gürtels, des sogenannten Punta-del-Este-Terrans, wird als Folge einer rückschreitenden Bogenorogenese entlang des aktiven westlichen Rands des Kongo-Kratons interpretiert. Dieses tektonische Umfeld, geprägt durch Subduktion und rückwärtige Extension, erklärt die beobachteten hochkaliumhaltigen kalk-alkalinen Gesteinstypen sowie die Kombination aus juvenilen und krustalen Isotopensignaturen im Grundgebirge. Detritische Zirkonspektren aus metasedimentären Gesteinen bestätigen zudem die geodynamische Verbindung zum Kaoko-Gürtel und weisen auf lokale magmatische Bogenquellen hin, was auf eine Ablagerung in einem syn- bis postmagmatischen Dehnungsmilieu schließen lässt. Die extensiven Verhältnisse im Bogen deuten außerdem auf eine teilweise Riftbildung des westlich angrenzenden Grundgebirges, des Nico-Pérez-Terrans, vom Kongo-Kraton hin – eine Interpretation, die durch geologische und geochronologische Korrelationen mit dem Angola-Schild gestützt wird.
Erstmals wird hier eine hochgradige Granulitfazies-Metamorphose im Nico-Pérez-Terran dokumentiert. Druck-Temperatur-Schätzungen liegen bei etwa 1,0–1,3 GPa und 800–850 °C, Titanit-U–Pb-Datierungen ergeben ein Alter von 650 ± 11 Millionen Jahren. Diese Bedingungen sind zeitgleich mit denen im Punta-del-Este–Küstenterran und deuten auf ein regionales kollisionsbedingtes Ereignis im Cryogenium hin, das mit der Bildung von Südwest-Gondwana verknüpft ist. Die Ergebnisse widersprechen bisherigen Modellen, die die Akkretion des Nico-Pérez-Terrans erst im Ediacarium annehmen, und stützen stattdessen seine frühere Position am Rand des Kongo-Kratons. Die schnelle, beinahe isotherme Exhumierung des orogenen Kerns – belegt durch die analysierten Mineralparagenesen – weist auf einen Übergang von frontaler zu schräger Konvergenz hin. Detritische Zirkonalter und Isotopendaten belegen zudem die Ähnlichkeit der Rocha-Formation – der Hauptdeckabfolge des Punta-del-Este-Terrans – mit Einheiten des Gariep-Gürtels. Strukturelle Beziehungen sprechen für eine Akkretion an den Dom-Feliciano-Gürtel vor etwa 580 Millionen Jahren.
Nach der Kollision setzte im Dom-Feliciano-Gürtel eine post-kollisionale Extension ein, begleitet von starkem Magmatismus während des Ediacariums. Dies führte zur Bildung von Becken mit umfangreicher vulkanischer Füllung, wie sie beispielsweise in der Sierra-de-Aguirre-Formation erhalten ist. Die späten Phasen des orogenen Zyklus waren geprägt durch transpressionale Deformation entlang großräumiger Scherzonen sowie durch Exhumierung im Zeitraum zwischen etwa 570 und 450 Millionen Jahren.
Insgesamt untermauern die neuen Befunde eine gemeinsame neoproterozoische tektonische Entwicklung des südamerikanischen Dom-Feliciano-Gürtels und des Kaoko-Gürtels in Westafrika. Darauf folgte eine spätere Akkretion des Gariep-Gürtels an diesen bereits vereinigten Komplex. Das hier vorgestellte Modell,mit einer tonischen rückschreitenden Bogenorogenese, partieller Riftbildung des Nico-Pérez-Terrans und großräumiger kryogener Metamorphose, bietet ein schlüssiges Bild für die geodynamische Entwicklung dieses Teils von Gondwana.The interaction of the main cratons that constitute the present-day configuration of South America and Africa, together with several minor blocks, led to the amalgamation of Southwest Gondwana in the late Neoproterozoic, a protracted orogenic process known as African/Brasiliano Orogeny. From a global perspective, the assembly of Gondwana was the result of the convergence that followed the early Neoproterozoic Rodinia break-up. However, the participation of many southern South American and African crustal blocks in Rodinia has been challenged and, therefore, the early Neoproterozoic geologic record of these regions may not necessarily record the Rodinia break-up. In this context, Tonian units in Western Gondwana are the key to understanding the transition from the break-up of Rodinia to the assembly of Gondwana.
This study presents new geological, petrological, and geochronological data from the South American Dom Feliciano Belt, formed due to the interaction of the Congo, Río de la Plata and Kalahari cratons, within the framework of the aforementioned orogeny. The results refine and extend our understanding of its Tonian–Cryogenian evolution, focusing on the geological record of its orogenic basement and associated cover successions. These findings also offer tighter constraints on its pre-collisional tectonic connection with the Kaoko Belt of southwestern Africa.
The Tonian evolution of its eastern portion, known as Punta del Este Terrane, is interpreted as the product of a retreating arc orogeny developed along the western active margin of the Congo Craton. This tectonic setting characterized by subduction with back-arc extension satisfactory explains the high-K calc-alkaline geochemical signatures and mixed juvenile–crustal isotopic characteristics recorded within its basement. Detrital zircon spectra from metasedimentary rocks associated to the last further confirm its conextion with the African Kaoko belt and indicate a component of local arc sources, supporting their deposition within a syn- to post-magmatic enviromment. The extensional nature of this arc also implies partial rifting of its western orogenic basement, the Nico Pérez Terrane, from the Congo Craton, a scenario reinforced by the geological and geochronological correlations explored in this study .
High-grade granulite-facies metamorphism within the Nico Pérez Terrane is here reported for the first time, with P–T estimates of ca. 1.0–1.3 GPa and 800 – 850°C, and titanite U–Pb ages yielding 650 ± 11 Ma. These metamorphic conditions are synchronous and comparable to those in the Punta del Este–Coastal Terrane, suggesting a regional Cryogenian collisional event associated with the amalgamation of South-west Gondwana. This evidence contradicts models that place the Nico Perez Terrane accretion in the Ediacaran, instead confirming its position at the border of the Congo Craton. The fast isotermal exhumation of the orogenic core, indicated by the studied mineral assambleges, suggests a shift from an initial frontal collision to oblique convergence. Detrital zircon ages and isotopic data indicate a Gariep-Belt-like nature of the Rocha Formation, the main cover succession of the Punta del Este Terrane, while structural relationships indicate its accretion to the Dom Feliciano Belt prior to ca. 580Ma.
Following the collisional phase, the Dom Feliciano experienced Ediacaran post-collsional extensional tectonics with associated widespread magmatism, leading to the formation of basins with important amounts of volcanic filling (e.g., the Sierra de Aguirre Formation). The final stages of the orogenic cycle were marked by transpressional deformation along regional-scale shear zones and exhumation between ca. 570 and 450 Ma.
Altogether, these new findings reinforce a shared Neoproterozoic tectonic evolution of the South-American Dom Feliciano Belt and the African Kaoko Belt in western Africa, followed by a later accretion of the Gariep Belt to the prior assamblage. The proposed model including a Tonian retreating-arc orogeny leading to the partial rifting of the NPT and widespread Cryogenian metamorphism, satisfactory explains the evolution of the considered portion of Gondwana.2026-01-1
Housing pigs with undocked tails: methods for the early detection and prevention of tail biting
Get PDFThe occurrence of tail biting is a widespread problem in global pig farming. Painful biting incidents lead to a significant impairment of animal health, animal welfare and the performance of pigs in various production stages. The background to this multifactorial behavioral disorder is very complex due to the large number of risk factors involved, which make targeted prevention and prediction almost impossible. Docking the pigs’ tails within the first few days of life has become a common and effective prevention strategy in agricultural practice, which is a short but painful procedure for the animal. This method has been officially banned in the EU for several years now, but it is still permitted if a farm has proven observed tail biting in its herd and other preventive measures have been implemented but have failed. Nevertheless, alternative strategies to prevent tail biting are needed in order to gradually avoid tail docking in the long term. The provision of organic enrichment material, for example, has proven to be particularly effective in promoting the animals' natural exploratory behavior and distracting them from the actual biting. In addition, the early detection and intervention of tail biting are essential in order to stop it as soon as the first biting occurred and to prevent it from escalating in the entire herd. For this approach, the potential and implementation of various digital systems is in the focus of the research and increasingly tested in practice. Those systems make it possible to continuously and objectively record animal behavior and housing conditions in order to individually support pig farms in their daily work.
The aim of this dissertation was to investigate possibilities for the prevention and early detection of tail biting in weaner pigs with intact tails by implementing different sensor systems in a piglet rearing compartment. To prevent tail biting, an automatic enrichment device with pen-specific supplies was installed in the compartment to regularly provide the pigs with pelleted organic material. This serves not only to prevent tail biting, but also to support the animals' natural exploratory behavior and thus increase animal welfare, which is to be evaluated in this dissertation. To objectively observe the animals' behavior, cameras with connected microphones were installed above each pen for continuously recording. In addition to the existing and described early indicators for tail biting, new methods for the early detection of this behavioral disorder in weaner pigs should be researched.
The first study investigated whether tail biting and in particular individual tail biters can be identified by recognizing pig screams in sound recordings, as the rapid removal of tail biters is an effective intervention strategy to maintain animal health and welfare. For this approach, 288 undocked rearing piglets were housed in six pens during two batches. The pigs were marked individually by colored ear tags and their tails were examined biweekly. The tail posture of the animals was recorded daily as a common early indicator for ongoing biting. As soon as the barn staff identified a tail biter (n = 7) during the daily animal checks, the video and audio recordings of the previous days were retrospectively analyzed for pig screams (sudden increase in volume with frequencies above 1 kHz) and evaluated in the video until no more biting incidents were observed anymore. A total of 2,893 screams were observed and analyzed in four tail-biting pens. Of these screams, 52.9 % were caused by tail biting in the observed pen, 25.6 % originated from other pens, 8.8 % were unclassifiable and 12.7 % were due to other causes. In the case of a tail biting incident, the screams were individually assigned to the biter and victim pigs by identifying them by their colored ear tags. Based on the audio analysis, tail biters were identified between one and nine days before they were removed by the farm staff. The screams were also recognized earlier than the increase in hanging tails and could therefore be favored as an early warning indicator. Analyzing the vocalizations of pigs to detect screams has the potential to identify tail biters at an early stage. In combination with individual animal markings and automatic analysis algorithms, tail biters could be identified and tail biting efficiently reduced. This would help the farmers to react faster and remove tail biters from the pen earlier in order to improve the health and welfare of the other animals.
In the second study, the effects of automatically supplied enrichment material of three different types (alfalfa pellets, oat bran pellets or a mixture of both) and different enrichment frequencies (2, 4 or 6 supplies/day) on the behavior, tail biting incidence and daily weight gain of weaned piglets were investigated during six batches. The results showed significant effects and interactions of material, frequency and time of day on exploratory behavior, the incidence of tail biting and daily weight gain. Pigs were most likely to use the enrichment material when they received only two supplies per day or oat bran pellets. In addition, more pigs explored the material when it was provided in the afternoon compared to the morning. Tail lesions increased significantly from the fourth week of rearing. The probability of a tail lesion occurring was highest in groups with two supplies per day. The groups that received two supplies per day also had the highest probabilities of a tail loss at the end of the rearing period, with 0.170 for alfalfa pellets, 0.342 for the mixture and 0.486 for oat bran pellets. For daily weight gain, only the alfalfa groups differed significantly from the mixture groups at two supplies/day. There were no differences for the other factor combinations. These results show the potential of an automated enrichment device to support the pigs in performing their natural exploratory behavior in a conventional housing system. A higher number of daily supplies is beneficial for reducing the occurrence of tail lesions and tail losses.
The third study builds on the first study with the aim of automatically detecting pig screams for the early identification of tail biters by developing a detector software that automatically analyses video and audio recordings and detects screams that can be caused by tail biting incidents. For this purpose, video recordings of rearing piglets from different pens and two batches were recorded over a period of 39 days each. Screams were automatically identified by the developed detector by analyzing the audio track of the video recordings and then evaluated by the outcome from the two batches of the first study. The results of the detector were assessed by testing various user-defined parameters (e.g. volume threshold, call duration, frequency range). A total of 2,898 screams were detected manually in four pens (748 hours), with 52.8 % caused by tail biting. In the second step, 89.9% of the detected screams were correctly classified as screams by the detector (accuracy 0.81-1.00), of which 64.0% were caused by tail biting. The detector automatically analyses the latest videos in user-defined time periods (e.g. hourly) and sends alerts via email if a threshold of screams per hour is exceeded in a pen. Subsequently, the detector extracts video clips that can be used for visually identifying the tail biters. In summary, the automatic analysis of pig screams has great potential for early detection and intervention of tail biting by recognizing tail biting events directly through the screams and providing video clips for identification of tail biters.
All in all, the various systems in the piglet rearing compartment had a positive influence and high potential on the prevention and early detection of tail biting. The automatic enrichment device was able to reduce the risk of tail injuries by increasing the enrichment frequency and encouraging the pigs’ natural exploratory behavior. Targeted evaluation of video recordings with an integrated audio track enables automatic scream detection, which can be used for identifying tail biting incidents. The direct detection of biting incidents in particular offers major advantages compared to other early indicators, as targeted intervention measures can be initiated like identifying and removing the biter. The automatic scream detection has great potential to support pig farms in their daily work and has already been tested over several rounds under practical conditions.2025-04-2
Longitudinal Structural Voxel based Morphometry of 1.5 tesla MRI in early Parkinson’s disease
Get PDFParkinson’s disease is a multisystemic, progressive neurodegenerative disorder characterized by the gradual loss of dopaminergic neurons in the substantia nigra, resulting in a wide range of motor and non-motor symptoms that extend beyond the classical features of rigidity, tremor, bradykinesia and postural instability. The incidence of Parkinson's disease is steadily increasing with demographic changes and requires biomarkers to detect the disease at an early stage in order to develop strategies for management with the disease and a form of therapy to be applied as early as possible. The aim of this thesis was to analyze a continuous reduction in grey matter volume in patients with newly diagnosed Parkinson's disease (DeNoVo) and healthy controls with structural voxel-based morphometry in vivo at baseline and after 2- and 4-year follow-up. Additionally, correlations between grey matter atrophy and clinical assessments such as the Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Clock Drawing Test (CDT) and the Movement Disorder Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) were examined across all three time points (BL, FU1, FU2). As part of the longitudinal DeNoPa study, structural MRI examinations of the participants were conducted using a 1.5-Tesla MRI at the radiology clinic in Baunatal-Kassel. Using voxel-based morphometry based on 3D-T1 images, volumetric changes in grey matter were assessed and statistically analyzed in 216 participants, including 118 patients with Parkinson’s disease and 98 healthy controls.
Over the course of the measurement time points, both Parkinson’s patients and healthy controls showed a significant reduction in grey matter and hippocampal volume.
The findings suggest that the volume loss in Parkinson’s patients was more pronounced and consistently significant across a greater number of regions, including four areas of the frontal lobe, five areas of the parietal lobe, four areas of the temporal lobe, three areas of the occipital lobe as well as the left caudate nucleus. The significant correlations between grey matter volume reductions, particularly in the frontal lobe and hippocampus, and cognitive performance in the aforementioned tests in Parkinson's patients suggest that cognitive decline and neuropsychiatric symptoms occur in the early stages of the disease. The detection of non-motor symptoms is of particular importance as they significantly impair the quality of life of those affected, make every day functioning more difficult and contribute significantly to the burden on caregivers.
The fact that the control group also showed a significant reduction of grey matter but no correlations with motor and cognitive tests, suggests that brain atrophy is subject to a physiological aging process.
The results in the present study suggest that although continuous brain atrophy in grey matter is common in PD patients and a heterogeneous atrophy pattern seems to exist, it cannot yet be considered a specific disease pattern for PD. Overall, the data highlight the potential of imaging as a biomarker in combination with cognitive tests in the early stages of the Parkinson’s disease and a risk stratification tool for the emergence of cognitive decline as NMS and dementia in de novo Parkinson’s patients. These findings underscore the importance of a multimodal diagnostic approach in Parkinson's disease, particularly in the early stages, integrating complementary assessments to capture the heterogeneous nature of the disorder, with special attention to non-motor symptoms.2025-05-2