Droplet digital PCR assays for the quantification of brown trout (Salmo trutta) and Arctic char (Salvelinus alpinus) from environmental DNA collected in the water of mountain lakes

Classical methods for estimating the abundance of fish populations are often both expensive, time-consuming and destructive. Analyses of the environmental DNA (eDNA) present in water samples could alleviate such constraints. Here, we developed protocols to detect and quantify brown trout (Salmo trutta) and Arctic char (Salvelinus alpinus) populations by applying the droplet digital PCR (ddPCR) method to eDNA molecules extracted from water samples collected in 28 Swedish mountain lakes. Overall, contemporary fish CPUE (catch per unit effort) estimates from standardized survey gill nettings were not correlated to eDNA concentrations for either of the species. In addition, the measured environmental variables (e.g. dissolved organic carbon concentrations, temperature, and pH) appear to not influence water eDNA concentrations of the studied fish species. Detection probabilities via eDNA analysis showed moderate success (less than 70% for both species) while the presence of eDNA from Arctic char (in six lakes) and brown trout (in one lake) was also indicated in lakes where the species were not detected with the gillnetting method. Such findings highlight the limits of one or both methods to reliably detect fish species presence in natural systems. Additional analysis showed that the filtration of water samples through 1.2 mu m glass fiber filters and 0.45 mu m mixed cellulose ester filters was more efficient in recovering DNA than using 0.22 mu m enclosed polyethersulfone filters, probably due to differential efficiencies of DNA extraction. Altogether, this work showed the potentials and limits of the approach for the detection and the quantification of fish abundance in natural systems while providing new insights in the application of the ddPCR method applied to environmental DNA

Stimulus-Related Independent Component and Voxel-Wise Analysis of Human Brain Activity during Free Viewing of a Feature Film

Understanding how the brain processes stimuli in a rich natural environment is a fundamental goal of neuroscience. Here, we showed a feature film to 10 healthy volunteers during functional magnetic resonance imaging (fMRI) of hemodynamic brain activity. We then annotated auditory and visual features of the motion picture to inform analysis of the hemodynamic data. The annotations were fitted to both voxel-wise data and brain network time courses extracted by independent component analysis (ICA). Auditory annotations correlated with two independent components (IC) disclosing two functional networks, one responding to variety of auditory stimulation and another responding preferentially to speech but parts of the network also responding to non-verbal communication. Visual feature annotations correlated with four ICs delineating visual areas according to their sensitivity to different visual stimulus features. In comparison, a separate voxel-wise general linear model based analysis disclosed brain areas preferentially responding to sound energy, speech, music, visual contrast edges, body motion and hand motion which largely overlapped the results revealed by ICA. Differences between the results of IC- and voxel-based analyses demonstrate that thorough analysis of voxel time courses is important for understanding the activity of specific sub-areas of the functional networks, while ICA is a valuable tool for revealing novel information about functional connectivity which need not be explained by the predefined model. Our results encourage the use of naturalistic stimuli and tasks in cognitive neuroimaging to study how the brain processes stimuli in rich natural environments

A Psychometric Evaluation of the Danish Version of the Theory of Mind Storybook for 8-14 Year-Old Children

Background: Theory-of-Mind (ToM) keeps on developing in late childhood and early adolescence, and the study of ToM development later in childhood had to await the development of sufficiently sensitive tests challenging more mature children. The current study aimed to investigate the psychometric properties of the Danish version of the Theory-of-Mind Storybook Frederik (ToM-Frederik). Methods: We assessed whether ToM-Frederik scores differed between a group of 41 typically developing (TD) children and a group of 33 children with High Functioning Autism Spectrum Disorder (HFASD). A lower mean ToM Frederik score was expected in the HFASD group. To determine the convergent validity of ToM-Frederik, potential associations with Strange Stories and Animated Triangles (AT) were analyzed. Furthermore, potential associations between ToM-Frederik and the Social Responsiveness Scale (SRS) and between ToM Frederik and the Social Emotional Evaluation (SEE) Total score were analyzed. Results: A significantly higher ToM-Frederik score was observed in the TD group compared to the HFASD group. Furthermore, the convergent validity of ToM-Frederik as a measure of ToM was supported by significant and positive associations with the Strange Stories and the AT scores in the HFASD group, whereas ToM-Frederik was significantly correlated with Strange Stories, but not with AT in the TD group. ToM-Frederik was not significantly associated with SRS in neither the HFASD nor the TD group. Conclusion: The findings are supportive of ToM-Frederik as a valid indicator of deficits at the group level in children with HFASD between 7 and 14 years of age. Furthermore, the convergent validity is supported

Problempflanzen im Straßenbegleitgrün - was geht, was geht nicht?

Der Artikel beschreibt und gibt Hinweise wie bestimmte Pflanzenarten Probleme im Bereich der Verkehrssicherheit erzeugen und ob und wie der Betriebsdienst der Meisterein die Bestandsregulierung erfüllen kann und sollte. Siehe Abstract unter: https://doi.org/10.53184/SVT5-2024-2 siehe auch "Praxishilfe Problempflanzen" unter: https://www.bast.de/DE/Verkehrstechnik/Fachthemen/Daten/Praxishilfe-Problempflanzen.pd

Herausforderungen durch problematische Arten – ein Überblick über die aktuelle Situation auf Straßenbegleitgrün

Straßenbegleitflächen können einerseits wertvolle Lebensräume für eine Vielzahl von Tier- und Pflanzenarten darstellen, die inzwischen nur noch selten in unserer intensiv genutzten Landschaft zu finden sind. Andererseits kommen auf ihnen häufig gebietsfremde Pflanzenarten (Neophyten) vor und breiten sich bevorzugt entlang dieser aus. Einige dieser Arten können die heimische Artenvielfalt oder die menschliche Gesundheit gefährden oder hohe ökonomische Kosten verursachen. Ziel des Kernthemas „Verkehrsträgerübergreifendes und –spezifisches Management von invasiven Arten“ im BMVI-Expertennetzwerk ist es, verkehrsträgerübergreifende Managementpläne zur Prävention der Einbringung und Ausbreitung von gebietsfremden Arten auf Verkehrsbegleitflächen zu entwickeln. Um eine verlässliche Einschätzung zu erhalten, inwieweit Neophyten bereits an Bundesfernstraßen etabliert sind und welche Problematik daraus resultiert, wurde eine online-Umfrage entwickelt, die an die zuständigen Betriebsdienste der Bundesländer gerichtet wurde. Hierzu werden die Ergebnisse vorgestellt. Diese sollen helfen, effiziente Bekämpfungsmaßnahmen und Strategien zur Vermeidung der Einbringung und Ausbreitung von Neophyten und anderen Problemarten zu entwickeln. Mittel- bis langfristig sollen diese zur (Kosten-) Entlastung bei der Unterhaltung bestehender und der Planung zukünftiger Infrastruktureinrichtungen führen

Ecology across Boundaries : Food web coupling among and within ecosystems

Cross-boundary movements of energy and material are ubiquitous. Freshwater ecosystems receive nutrients, dissolved, and particulate organic matter from adjacent terrestrial ecosystems, whereas terrestrial ecosystems mainly receive prey organisms and detritus deposited by physical processes such as floods from freshwater ecosystems. Within lakes, fish are considered as integrators between habitats due to their high mobility, although they often occupy either near-shore littoral or open-water pelagic habitats and develop habitat-specific morphologies. Such intra-population divergence in morphological traits might limit the use of multiple habitats. In this thesis, I first focused on quantity and quality of reciprocal fluxes of particulate organic matter between freshwater and terrestrial ecosystems and responses of recipient consumers. Freshwater ecosystems generally received higher amounts of externally-produced resources than terrestrial ecosystems. Despite this discrepancy, aquatic and terrestrial consumer responses were similar, likely due to the differences in resource quality. Second, I investigated the potential of particulate organic carbon (POC) supporting benthic food webs in lakes; a pathway that has largely been neglected in previous studies. I found that POC can substantially subsidize the benthic food web and that the effects on the benthic food web were transferred to the pelagic habitat, thus emphasizing the importance of benthic pathways for pelagic production. Third, I examined how water transparency can affect intra-population divergence in perch (Perca fluviatilis). I observed that increased water transparency can considerably increase morphological divergence between littoral and pelagic populations likely due to its effects on foraging. Finally, I investigated the effects of such intra-population divergence on littoral-pelagic food web coupling. I found that low morphological divergence corresponded with high overlap in resource use, whereas strong morphological divergence resulted in low overlap in resource use. Here littoral populations mainly utilized littoral resources and pelagic populations primarily utilized pelagic resources, indicating that habitat coupling might be strongly limited when intra-population divergence is high. In conclusion, although different ecosystems seem separated by distinct physical boundaries, these boundaries are often crossed. However, the development of habitat-specific adaptive traits might limit movement between apparently contiguous habitats

Ecology across Boundaries : Food web coupling among and within ecosystems

Cross-boundary movements of energy and material are ubiquitous. Freshwater ecosystems receive nutrients, dissolved, and particulate organic matter from adjacent terrestrial ecosystems, whereas terrestrial ecosystems mainly receive prey organisms and detritus deposited by physical processes such as floods from freshwater ecosystems. Within lakes, fish are considered as integrators between habitats due to their high mobility, although they often occupy either near-shore littoral or open-water pelagic habitats and develop habitat-specific morphologies. Such intra-population divergence in morphological traits might limit the use of multiple habitats. In this thesis, I first focused on quantity and quality of reciprocal fluxes of particulate organic matter between freshwater and terrestrial ecosystems and responses of recipient consumers. Freshwater ecosystems generally received higher amounts of externally-produced resources than terrestrial ecosystems. Despite this discrepancy, aquatic and terrestrial consumer responses were similar, likely due to the differences in resource quality. Second, I investigated the potential of particulate organic carbon (POC) supporting benthic food webs in lakes; a pathway that has largely been neglected in previous studies. I found that POC can substantially subsidize the benthic food web and that the effects on the benthic food web were transferred to the pelagic habitat, thus emphasizing the importance of benthic pathways for pelagic production. Third, I examined how water transparency can affect intra-population divergence in perch (Perca fluviatilis). I observed that increased water transparency can considerably increase morphological divergence between littoral and pelagic populations likely due to its effects on foraging. Finally, I investigated the effects of such intra-population divergence on littoral-pelagic food web coupling. I found that low morphological divergence corresponded with high overlap in resource use, whereas strong morphological divergence resulted in low overlap in resource use. Here littoral populations mainly utilized littoral resources and pelagic populations primarily utilized pelagic resources, indicating that habitat coupling might be strongly limited when intra-population divergence is high. In conclusion, although different ecosystems seem separated by distinct physical boundaries, these boundaries are often crossed. However, the development of habitat-specific adaptive traits might limit movement between apparently contiguous habitats

Neophyte management on road verges

Straßenbegleitflächen können wertvolle Lebensräume für eine Vielzahl von Tier- und Pflanzenarten bieten und damit einen Beitrag zum Erhalt und der Förderung der Biodiversität leisten. Gleichzeitig kommen aber auch gebietsfremde Pflanzenarten (Neophyten) auf Straßenbegleitflächen vor und breiten sich bevorzugt entlang dieser aus. Einige dieser Arten können eine Gefahr für die Biodiversität darstellen, hohe ökonomische Kosten verursachen oder die menschliche Gesundheit gefährden. Ziel der vorliegenden Untersuchung war eine Erhebung der Verbreitung von Neophyten, den auftretenden Problemen und gegebenenfalls bereits ergriffener Maßnahmen zu deren Kontrolle auf Begleitgrün der Bundesfernstraßen in Deutschland. Um eine verlässliche Einschätzung zu erhalten, wurde eine online-Umfrage entwickelt, die an die zuständigen Straßen- und Autobahnmeistereien der Bundesländer gerichtet wurde. Dabei wurden 12 Fragen zu 10 ausgewählten Neophyten gestellt. Die Rücklaufrate betrug über 40 %. Laut der Angaben der Teilnehmer kommen die meisten der in der Umfrage aufgeführten Neophyten häufig auf Straßenbegleitflächen vor. Die beiden Arten, die laut der Umfrage am häufigsten vorkommen, die Herkulesstaude (Heracleum mantegazzianum) und der japanische Staudenknöterich (Fallopia japonica), verursachen auch die häufigsten Probleme in den Zuständigkeitsbereichen. Die Teilnehmer gaben an, dass die Herkulesstaude zu gesundheitlichen Problemen, der Staudenknöterich zu Sichtbehinderungen und beide Arten zu einem erhöhten Pflegeaufwand führen. Beide Arten werden in einem Großteil der Zuständigkeitsbereiche aktiv bekämpft. Die Herkulesstaude wird relativ erfolgreich durch manuelle oder chemische Maßnahmen beseitigt, während Maßnahmen gegen den Staudenknöterich größtenteils nicht erfolgreich sind. Auch Maßnahmen gegen die anderen aufgeführten Neophyten führen nur selten zu einer vollständigen und dauerhaften Beseitigung der Bestände. Die Umfrage verdeutlicht, dass ein dringender Bedarf an Maßnahmen zur Kontrolle von Neophyten, vor allem des Staudenknöterichs, besteht. Auf Grundlage dieser Ergebnisse sollen effiziente Bekämpfungsmaßnahmen und Strategien zur Vermeidung der Einbringung und Ausbreitung von Neophyten entwickelt werden. Mittel- bis langfristig sollen diese zur (Kosten-)Entlastung bei der Unterhaltung bestehender und der Planung zukünftiger Infrastruktureinrichtungen führen.Road verges can offer valuable habitats for many animal and plant species and thus contribute to maintain and promote biodiversity. At the same time many alien plant species (neophytes) occur on road verges and preferably spread along road sides. Some of those species can threaten biodiversity, cause high economic costs or can be a risk to human health. The objective of the present study was to investigate the occurrence of neophytes, problems caused by neophytes and measures applied to control neophytes on road verges along federal roads in Germany. In order to obtain a reliable estimate, we developed an online-survey that was sent out to the relevant road/highway maintenance departments in all federal states. The survey included 12 questions about 10 selected neophytes. The return rate exceeded 40%. Most of the selected neophytes occurred frequently on road verges according to the participants. The two species that occurred most frequently, giant hogweed (Heracleum mantegazzianum) and Japanese knotweed (Fallopia japonica), commonly caused problems in the areas of responsibility. The participants indicated that giant hogweed caused health problems while Japanese knotweed caused line-of-sight obstructions. The occurrence of both species results in higher maintenance efforts. Both species are actively controlled in many areas of responsibility. Giant hogweed can be controlled comparatively successfully by manual removal or with herbicides, whereas control measures for Japanese knotweed are mostly unsuccessful. Moreover, control measures for the other selected neophytes rarely result in complete and permanent removal of populations. The survey emphasises the urgent need for control measures of neophytes, in particular of Japanese knotweed. The results should help to develop efficient control measures and strategies to prevent the establishment and spread of neophytes. On intermediate to long-term they should result in a (cost) release in maintenance of existing and planned infrastructure facilities

Ecology across Boundaries : Food web coupling among and within ecosystems

Cross-boundary movements of energy and material are ubiquitous. Freshwater ecosystems receive nutrients, dissolved, and particulate organic matter from adjacent terrestrial ecosystems, whereas terrestrial ecosystems mainly receive prey organisms and detritus deposited by physical processes such as floods from freshwater ecosystems. Within lakes, fish are considered as integrators between habitats due to their high mobility, although they often occupy either near-shore littoral or open-water pelagic habitats and develop habitat-specific morphologies. Such intra-population divergence in morphological traits might limit the use of multiple habitats. In this thesis, I first focused on quantity and quality of reciprocal fluxes of particulate organic matter between freshwater and terrestrial ecosystems and responses of recipient consumers. Freshwater ecosystems generally received higher amounts of externally-produced resources than terrestrial ecosystems. Despite this discrepancy, aquatic and terrestrial consumer responses were similar, likely due to the differences in resource quality. Second, I investigated the potential of particulate organic carbon (POC) supporting benthic food webs in lakes; a pathway that has largely been neglected in previous studies. I found that POC can substantially subsidize the benthic food web and that the effects on the benthic food web were transferred to the pelagic habitat, thus emphasizing the importance of benthic pathways for pelagic production. Third, I examined how water transparency can affect intra-population divergence in perch (Perca fluviatilis). I observed that increased water transparency can considerably increase morphological divergence between littoral and pelagic populations likely due to its effects on foraging. Finally, I investigated the effects of such intra-population divergence on littoral-pelagic food web coupling. I found that low morphological divergence corresponded with high overlap in resource use, whereas strong morphological divergence resulted in low overlap in resource use. Here littoral populations mainly utilized littoral resources and pelagic populations primarily utilized pelagic resources, indicating that habitat coupling might be strongly limited when intra-population divergence is high. In conclusion, although different ecosystems seem separated by distinct physical boundaries, these boundaries are often crossed. However, the development of habitat-specific adaptive traits might limit movement between apparently contiguous habitats

Management von Verkehrsbegleitflächen − Förderung der Biodiversität und Umgang mit gebietsfremden Arten

Verkehrsbegleitflächen können wertvolle Lebensräume für eine Vielzahl von Tier- und Pflanzenarten bieten und damit einen Beitrag zum Erhalt und der Förderung der Biodiversität leisten. Gleichzeitig kommen aber auch gebietsfremde Pflanzenarten (Neophyten) auf Verkehrsbegleitflächen vor und breiten sich bevorzugt entlang dieser aus. Einige dieser Arten können eine Gefahr für die Biodiversität darstellen, hohe ökonomische Kosten verursachen oder die menschliche Gesundheit gefährden. Ziel der beiden Schwerpunktthemen SPT 201 „Ökologische Vernetzung“ und SPT 202 „Neobiota“ im BMVI-Expertennetzwerk ist es, verkehrsträgerübergreifende Managementpläne zur Prävention der Ein- und Ausbreitung von gebietsfremden Arten und zur Förderung der Biodiversität auf Verkehrsbegleitflächen zu entwickeln. Um eine verlässliche Einschätzung zu erhalten, inwieweit Neophyten bereits an Bundesstraßen und der Schiene etabliert sind und welche Problematik daraus resultiert, wurde eine online-Umfrage entwickelt, die an die zuständigen Betriebsdienste der Bundesländer und die Außenbezirke der DB Netz gerichtet wurde. Hierzu werden die vorläufigen Ergebnisse vorgestellt. Diese sollen helfen, effiziente Bekämpfungsmaßnahmen und Strategien zur Vermeidung der Einbringung und Ausbreitung von Neophyten zu entwickeln. Mittel- bis langfristig sollen diese zur (Kosten-) Entlastung bei der Unterhaltung bestehender und der Planung zukünftiger Infrastruktureinrichtungen führen