Michael Traugott

University of Innsbruck | UIBK · Institute of Ecology

Intraguild predation is an extreme form of competition, that depends on resource availability, niche overlap, behaviour and diversity. However, despite modelling and mesocosm experiments, field studies are scarce, and we know nothing of its temporal dynamics within real-world food webs, particularly in the context of biological control. To address...

Knowledge of trophic interaction is necessary to understand the dynamics of ecosystems and develop ecosystem-based management. The key data to measure these interactions should come from large-scale diet analyses with good taxonomic resolution. To that end, molecular methods that analyze prey DNA from guts and feces provide high-resolution dietary...

Understanding trophic interactions in agroecosystems is crucial for harnessing ecosystem services such as pest control, thus enabling a reduction in pesticide use. Carabid beetles (Coleoptera: Carabidae) have the potential to regulate not only insect pests but also weed seeds and slugs. The aim of this study was to investigate the food choice of di...

The combination of entomopathogenic fungi (EPF) and trap crops was tested for its control potential of a below-ground pest insect in potatoes. Results of this field experiment showed synergistic control performance of wireworm damage and their abundance when both were combined. Especially with high wireworm abundances trap crops boosted the damage...

DNA metabarcoding is increasingly important for studying feeding interactions, yet it remains unresolved whether reporting read counts or occurrences is to be preferred. To address this issue for gut content samples, basic experimental data on the relationship between read numbers and initial prey DNA amounts and how both change over digestion time...

Many omnivorous arthropods act as important pest control agents in agroecosystems. Assessing their prey choices helps to better understand their biocontrol potential in different environmental settings. To this end, multi‐target approaches of molecular gut content analysis allow studying their prey choices. Yet, DNA‐based analysis of trophic intera...

The feeding ecology of the Great Cormorant Phalacrocorax carbo has been the subject of many studies in which the hard parts of fish, contained in dietary samples such as regurgitated pellets, were identified using morphological characteristics. However, morphological prey identification does not necessarily permit the reliable identification of all...

The analysis of environmental DNA (eDNA) is revolutionizing the monitoring of biodiversity as it allows to assess organismic diversity at large scale and unprecedented taxonomic detail. However, eDNA consists of an extracellular and intracellular fraction, each characterized by particular properties that determine the retrievable information on whe...

Facultative scavenging by predatory carnivores is a prevalent but frequently underestimated feeding strategy. DNA‐based methods for diet analysis, however, do not allow to distinguish between scavenging and predation, thus, the significance of scavenging on population dynamics and resource partitioning is widely unknown. Here, we present a methodol...

Piscivorous birds in aquatic ecosystems exert predation pressure on fish populations. But the site‐specific impact on fish populations, including stocked and commercially used fish species, remains disputed. One of the key questions for the management of piscivorous birds and fish is determining the origin of prey and thus which fish populations ar...

Over the last years, the analysis of environmental DNA (eDNA) has become an important approach to investigate species communities. Due to its non-invasive nature and high sensitivity, this method is excellently suited to monitor the occurrence of endangered or invasive species. Native freshwater crayfish are threatened across Europe. Due to their n...

High-throughput sequencing platforms are increasingly being used for targeted amplicon sequencing because they enable cost-effective sequencing of large sample sets. For meaningful interpretation of targeted amplicon sequencing data and comparison between studies, it is critical that bioinformatic analyses do not introduce artefacts and rely on det...

The focus of this study was to assess the potential of otolith microchemistry as a fishery management tool for different European freshwater fish species in an Alpine foreland with a diverse range of different water bodies but low geological variation. ⁸⁷ Sr/ ⁸⁶ Sr isotope and Sr/Ca ratios in water samples from 26 habitat sites in a pre-alpine catc...

The use of sensitive methods is key for the detection of target taxa from trace amounts of environmental DNA (eDNA) in a sample. In this context, digital PCR (dPCR) enables direct quantification and is commonly perceived as more sensitive than endpoint PCR. However, endpoint PCR coupled with capillary electrophoresis (celPCR) potentially embodies a...

DNA-based diet analysis of natural enemies is a valuable tool for unravelling the food choice of predators in agroecosystems. It enables the rapid identification of potential biocontrol agents of invertebrate pests. Here, we present a new multiplex PCR system for the identification of pest slug species in the diet of their natural enemies such as c...

Increased climate variability as a result of anthropogenic climate change can threaten the functioning of ecosystem services. However, diverse responses to climate change among species (response diversity) can provide ecosystems with resilience to this growing threat. Measuring and managing response diversity and resilience to global change are key...

Molecular analyses of feces are widely used to study the feeding ecology of bats. However, little is known about how detectability of prey DNA from bat feces is influenced by gut retention time, mass of prey eaten, or prey identity, which hampers the interpretation of field data. Here, we address these knowledge gaps by conducting a feeding experim...

The use of environmental DNA (eDNA) analysis for species monitoring requires rigorous validation—from field sampling to the analysis of PCR‐based results—for meaningful application and interpretation. Assays targeting eDNA released by individual species are typically validated with no predefined criteria to answer specific research questions in one...

eDNA analysis is ideally suited to monitor the occurrence of endangered or invasive species because of its non-invasive nature and high sensitivity. European freshwater crayfish are threatened across the whole continent. Classical crayfish monitoring is challenging and time consuming due to their nocturnal activity and hidden lifestyle. Therefore,...

Environmental DNA (eDNA) analysis utilises trace DNA released by organisms into their environment for species detection and is revolutionising non ‐ invasive species and biodiversity monitoring. However, this technology requires rigorous validation along the whole workflow – from field sampling to statistical analysis – to ensure appropriate and me...

Amphibians globally belong to the most threatened animal groups and monitoring their populations is of critical importance for their conservation. The fire salamander ( Salamandra salamandra ) is one of the European amphibian species which has been experiencing drastic regional population declines due to the spread of the invasive chytrid fungus Ba...

The quantitative measurement of environmental DNA (eDNA) from field-collected water samples is gaining importance for the monitoring of fish communities and populations. The interpretation of these signal strengths depends, among other factors, on the amount of target eDNA shed into the water. However, shedding rates are presumably associated with...

Assessing the status and distribution of fish populations in rivers is essential for management and conservation efforts in these dynamic habitats. Currently, methods detecting environmental DNA (eDNA) are being established as an alternative and/or complementary approach to the traditional monitoring of fish species. In lotic systems, a sound under...

Carabids are generalist predators that contribute to the agricultural ecosystem service of seedbank regulation via weed seed predation. To facilitate adoption of this ecosystem services by farmers, knowledge of weed seed predation and the resilience of seedbank regulation with co-varying availability of alternative prey is crucial. Using assessment...

The quantitative measurement of eDNA form field-collected water samples is gaining importance for the monitoring of fish communities and populations. The interpretation of these signal strengths depends, among other factors, on the amount of target eDNA shed into the water. However, shedding rates are presumably associated with species-specific tra...

The use of sensitive methods is key for the detection of target taxa, from trace amounts of environmental DNA (eDNA) in a sample. In this context, digital PCR (dPCR) enables direct quantification and is commonly perceived as more sensitive than endpoint PCR. However, endpoint PCR coupled with capillary electrophoresis (celPCR) potentially embodies...

Trophic interactions are monitored by molecular methods based on the identification of prey DNA in feces, regurgitates, or the gut content of consumers. In providing highly resolved taxonomic information on dietary choice, DNA‐based analysis has become a key approach to unraveling the structure and dynamics of food webs. It is crucial, however, to...

Assessing the status and distribution of fish populations in rivers is essential for management and conservation efforts in these dynamic habitats and currently, environmental DNA (eDNA) is established as an alternative and/or complementary approach to the traditional monitoring of fish species. In lotic systems, a sound understanding of hydrologic...

Fish are both consumers and prey and as such part of a dynamic trophic network. Measuring how they are trophically linked, both directly and indirectly, to other species is vital to comprehend the mechanisms driving alterations in fish communities in space and time. Moreover, this knowledge also helps to understand how fish communities respond to e...

Environmental DNA (eDNA) analysis utilises trace DNA released by organisms into their environment for species detection and is revolutionising non-invasive species monitoring. The use of this technology requires rigorous validation - from field sampling to interpretation of PCR-based results - for meaningful application and interpretation. Assays t...

Abundance and diversity of natural enemies increases with higher landscape complexity. However, more species can also increase negative interactions such as intraguild predation (IGP), which could be detrimental to pest control. Direct observations of these trophic interactions are still lacking. In the present study, we employed DNA-based gut cont...

Potamodromous fish are considered important indicators of habitat connectivity in freshwater ecosystems, but they are globally threatened by anthropogenic impacts. Hence, non-invasive techniques are necessary for monitoring during spawning migrations. The use of environmental DNA (eDNA) potentially facilitates these efforts, albeit quantitative exa...

Functional redundancy can increase the resilience of ecosystem processes by providing insurance against species loss and the effects of abundance fluctuations. However, due to the difficulty of assessing individual species' contributions and the lack of a metric allowing for a quantification of redundancy within communities, few attempts have been...

Agricultural intensification can impact agrobiodiversity in several ways such as in terms of population densities, community composition and food web interactions across all trophic levels. This effect can be investigated at two scales: field-scale and landscape scale. Here it was assessed how the impact of fertilisation (within field) and landscap...

Carabid beetles are abundant in temperate agroecosystems and can play a pivotal role as biocontrol agents. While there is good knowledge regarding their effects on invertebrate pests in some systems, comparably little is known on the rate of seed feeding under field conditions. Molecular approaches are ideally suited for investigating carabid feedi...

• The bird cherry‐oat aphid Rhopalosiphum padi is a major cereal pest with an almost cosmopolitan distribution. As one of the main groups of biocontrol agents for aphids, numerous Aphidiinae are associated with R. padi, including the genera Binodoxys and Trioxys. • As a recently described species parasitizing R. padi, Trioxys sunnysidensis is recor...

Most ecosystem functions and related services involve species interactions across trophic levels, for example, pollination and biological pest control. Despite this, our understanding of ecosystem function in multitrophic communities is poor, and research has been limited to either manipulation in small communities or statistical descriptions in la...

The nucleotide variation in the cytochrome c oxidase subunit I (COI) gene makes it ideal for assigning sequences to species. However, this variability also makes it difficult to design truly universal primers. Here, we present the forward primer “Sauron‐S878,” specifically designed to facilitate library preparation for metabarcoding. This primer is...

Next Generation sequencing (NGS) is increasingly used for diet analyses; however, it may not always describe diet samples well. A reason for this is that diet samples contain mixtures of food‐DNA in different amounts as well as consumer‐DNA which can reduce the food‐DNA characterized. Because of this, detections will depend on the relative amount a...

Carabids are abundant in temperate agroecosystems and play a pivotal role as biocontrol agents for weed seed and pest regulation. While there is good knowledge regarding their effects on invertebrate pests, direct evidence for seed predation in the field is missing. Molecular approaches are ideally suited to investigate these feeding interactions;...

Piscivorous birds frequently display sex‐specific differences in their hunting and feeding behavior, which lead to diverging impacts on prey populations. Cormorants (Phalacrocoracidae), for example, were previously studied to examine dietary differences between the sexes and males were found to consume larger fish in coastal areas during autumn and...

Primary succession on bare ground surrounded by intact ecosystems is, during its first stages, characterized by predator‐dominated arthropod communities. However, little is known on what prey sustains these predators at the start of succession and which factors drive the structure of these food webs. As prey availability can be extremely patchy and...

Facultative bacterial endosymbionts can protect their aphid hosts from natural enemies such as hymenopteran parasitoids. As such, they have the capability to modulate interactions between aphids, parasitoids and hyperparasitoids. However, the magnitude of these effects in natural aphid populations and their associated parasitoid communities is curr...

Drosophila suzukii (Diptera: Drosophilidae) is a highly polyphagous invasive pest threatening fruit production in the Americas and Europe. The current knowledge of its host plants is mainly based on oviposition and larval development in fruits, while little is known on the diet of the adult flies. This information is important for developing effect...

Food web structure influences ecosystem functioning and the strength and stability of associated ecosystem services. With their broad diet, generalist predators represent key nodes in the structure of many food webs and they contribute substantially to ecosystem services such as biological pest control. However, until recently it has been difficult...

Alpine grasslands in Europe were shaped by traditional low-input management for centuries. Especially those above the natural treeline were used as summer pastures for sheep and cattle. However, little knowledge is available on the structure and function of soil macro-invertebrate communities of high alpine zones (i.e. high elevation and high latit...

Soil macro-invertebrates play an important role in the formation and functioning of soils, which makes them indispensable for all terrestrial ecosystems, including high alpine soils. However, in the latter, knowledge on species identity, diversity, and functionality of macro-invertebrate soil communities is scarce. Here, we address this knowledge g...

The rapidly growing field of molecular diet analysis is becoming increasingly popular among ecologists, especially when investigating methodologically challenging groups, such as invertebrate generalist predators. Prey DNA detection success is known to be affected by multiple factors, however, the type of dietary sample has rarely been considered....

The vinegar fly Drosophila suzukii (Matsumura) is an invasive species that attacks ripening fruits and berries, leading to considerable losses in fruit production. So far, management mainly relies on chemical and cultural control, but additional measures such as biological control are needed. Hence, for the development of sustainable control measur...

The “habitat heterogeneity hypothesis” predicts positive effects of structural complexity on species coexistence. Increasing habitat heterogeneity can change the diversity (number of species, abundances) and the functional roles of communities. The latter, however, is not well understood as species and individuals may respond very differently and d...

Analysis of predator–prey interactions is a core concept of animal ecology, explaining structure and dynamics of animal food webs. Measuring the functional response, i.e. the intake rate of a consumer as a function of prey density, is a powerful method to predict the strength of trophic links and assess motives of prey choice, particularly in arthr...

Parasitoids are important natural enemies of aphids in wheat fields of northern China, and interest in them has increased in recent years. However, little is known regarding parasitoids of wheat aphids, which has hindered the study and understanding of aphid-parasitoid interactions. In the present study, three primary parasitoids and 15 hyperparasi...

Molecular methods allow non-invasive assessment of vertebrate predator-prey systems at high taxonomic resolution by examining dietary samples such as faeces and pellets. To facilitate the interpretation of field-derived data, feeding trials, investigating the impacts of biological, methodological, and environmental factors on prey DNA detection hav...