Natural and human-induced dynamics in plant–animal mutualistic networks

Species interactions are an integral part of ecological communities. Collectively, these interactions form complex and highly dynamic networks. The structure of these networks varies due to geographic and temporal variation in the abundance and co-occurrence of interacting species and due to species gains and losses after anthropogenic perturbation. In Europe’s last relict of old-growth lowland forest (Białowieża, Poland), I studied the outcomes of these natural and human-induced dynamics in highly diversified mutualistic networks of plants, pollinators and seed dispersers. These mutualistic interactions between plants and free-living animals are of great importance, as the flowers and fruits of many plant species are critical resources for a variety of animal species, which in turn contribute significantly to the regeneration of plant communities. As part of my studies, I was able to show that plant–animal mutualistic networks are highly dynamic systems that respond collectively to changing biotic context and human-induced perturbation. Observed shifts in facilitative and competitive interactions among plants sharing mutualistic partners show that biotic context is a strong determinant of the outcome of interspecific interactions. The use of network analyses, thereby, allowed me to identify some of the mechanisms that shape species interactions and their outcomes. For example, my studies show that a change in the population density of one species suffices to trigger cascading effects on the interactions and populations of other species. This finding highlights that species interactions may have a pervasive effect on the assembly and disassembly of ecological communities. Even more importantly, I could show that these community-wide dynamics were in all cases linked to consumer-resource relationships, which are key determinants of plant–animal mutualisms. Thus, changes in the foraging behaviour of animals in response to variation in the density of plant resources and competitors affected the structure of mutualistic communities. This underscores that despite the evolutionary conservatism in ecological interactions, biotic context determines to which extent these coevolved interactions are realized. The fact that the sharing of mutualistic partners among plant species was reflected in their co-occurrence demonstrates that the above-mentioned dynamics in ecological networks may also determine community assembly processes and species co-existence. Importantly, the comparison of several types of species interactions revealed how biotic context in its various forms can shape land-use effects on species interactions. I found that the mutualism between plants and seed dispersers was more susceptible to habitat degradation than the mutualism between plants and their pollinators. This finding highlights that a high degree of generalization, such as in the seed dispersal mutualism, does not necessarily buffer ecological communities against the loss of species. This becomes even more important if a few species have a disproportionate effect on a given target function and if species are particularly vulnerable to ecological perturbation, such as habitat specialists or large-bodied frugivores. Furthermore, I observed that shifts in the abundance of plant resources in degraded habitats can amplify land-use effects on plant–animal mutualistic interactions. Importantly, changes in the density of plant resources explained about 40 to 70 percent of the variation in land-use effects on interactions between plants and their pollinators and seed dispersers. This demonstrates that a consideration of biotic context (e.g. in the form of resources) may considerably improve predictions of the magnitude of land-use effects on species interactions. Thereby, the correlated responses of pollinators and seed dispersers to the shifts in plant population densities in degraded habitats highlight that these dynamics are not restricted to single types of interaction, but potentially operate at the level of ecosystems. Studies that only focus on subsets of species or interaction types may be unable to identify the consequences of human land-use that have been shown here. In principle, the results of the presented studies may also be valid for other types of mutualistic and antagonistic interactions that are based on consumer-resource relationships. Altogether, the results of my thesis suggest that natural and human-induced dynamics in plant–animal mutualistic networks follow similar principles. In the worst case these dynamics might have cascading effects on the functioning and integrity of ecosystems through a parallel loss of multiple animal-mediated ecosystem services after habitat degradation

Importance of momentum dependent interactions for the extraction of the nuclear equation of state from high-energy heavy ion collisions

We demonstrate that momentum-dependent nuclear interactions (MDI) have a large effect on the dynamics and on the observables of high-energy heavy-ion collisions: A soft potential with MDI suppresses pion and kaon yields much more strongly than a local hard potential and results in transverse momenta intermediate between soft and hard local potentials. The collective-flow angles and the deuteron-to-proton ratios are rather insensitive to the MDI. Only simultaneous measurements of these observables can give clues on the nuclear equation of state at densities of interest for supernova collapse and neutron-star stability

The role of quantum effects and nonequilibrium transport coefficients for relativistic heavy ion collisions

Stopping power and thermalization in relativistic heavy ion collisions is investigated employing the quantum molecular dynamics approach. For heavy systems stopping of the incoming nuclei is predicted, independent of the energy. The influence of the quantum effects and their increasing importance at low energies, is demonstrated by inspection of the mean free path of the nucleons and the n-n collision number. Classical models, which neglect these effects, overestimate the stopping and the thermalization as well as the collective flow and squeeze out. The sensitivity of the transverse and longitudinal momentum transfer to the in-medium cross section and to the pressure is investigated

Religionswissenschaft und Ideologiekritik

Der Artikel befasst sich mit Kurt Rudolphs Konzept der »Ideologiekritik« bzw. dem ideologiekritischen Potential der Religionswissenschaft. Es ist das Ziel der Ausführungen, die Notwendigkeit einer ideologiekritischen Betrachchtung der zeitgenössischen Religionswissenschaft herauszuarbeiten. Im ersten Teil des Beitrages wird Rudolphs Konzeption nachvollzogen. Dabei stehen die Bestimmungen der Begriffe Ideologie und Religion durch Rudolph und ihr Verhältnis zueinander im Zentrum der Ausführungen. Im zweiten Teil wird der historisch-politische Kontext von Rudolphs Überlegungen aufgezeigt. Dabei werden diese als Reaktion auf die Versuche der ideologischen Vereinnahmung der Religionswissenschaft von außen gedeutet. Im dritten Teil werden verschiedene Gegenstände religionswissenschaftlicher Ideologiekritik unterschieden, anhand welcher die Legitimität oder Notwendigkeit einer ideologiekritischen Reflexion des Faches in der Gegenwart diskutiert werden wird

Vom „Kohlrabi-Apostel“ zum „Bionade-Biedermeier“

For Jörg Albrecht, the increasing problematisation of meat consumption and the revaluation of sustainable nutritional styles is the starting point for a reconstruction of the history of alternative nutrition in Germany from the perspective of religious studies. From organised vegetarianism in the 19th century to wholefoods and natural foods in the 20th century to the "organic boom" of the recent past, he traces and analyses the transformations of non-conformist innovations into supposed mainstream phenomena: What exactly was adapted and made compatible and how? What factors influenced the processes? With his synthesis, Albrecht makes a sound theoretical contribution to modelling cultural dynamics.PublishedDie zunehmende Problematisierung von Fleischkonsum und die Aufwertung nachhaltiger Ernährungsstile sind für Jörg Albrecht Ausgangspunkt für eine Rekonstruktion der Geschichte alternativer Ernährung in Deutschland aus religionswissenschaftlicher Perspektive. Vom organisierten Vegetarismus im 19. Jahrhundert über Vollwert- und Naturkost im 20. Jahrhundert bis zum „Bio-Boom“ der jüngsten Vergangenheit zeichnet er die Transformationen von nonkonformistischen Innovationen zu vermeintlichen Mainstreamphänomenen nach und analysiert: Was genau wurde wie adaptiert und kompatibel gemacht? Welche Faktoren haben die Prozesse beeinflusst? Mit seiner Synthese leistet Albrecht einen fundierten theoretischen Beitrag zur Modellierung kultureller Dynamike

Vehicular Cooperative Maneuvers -- Quo Vaditis?

Vehicles will not only get more and more automated, but they will also cooperate in new ways. Currently, human-driven vehicles begin to communicate with each other using vehicle-to-everything technology. Future vehicles will use communication to share sensor data and even negotiate cooperative maneuvers. This lets them learn more about the environment and improves traffic flow and passenger comfort as more predictable maneuvers are likely to lead to a smoother ride. This paper introduces the most important concepts around cooperative vehicular maneuvers. We also summarize currently open challenges and questions to answer before a deployment can begin. Afterward, we give some perspectives on the further evolution of cooperative maneuvers and beyond.Comment: 8 pages incl. references and author biographies, 4 figures incl. multiple sub-figure