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Site-specific survey and reference data reveal drivers of fish community diversity changes in southwest Germany
No full textDespite efforts to minimize human impact on rivers, native teleost fish and lamprey species communities in Germany remain threatened. The aim of the study was to quantify current species diversity in the study area, identify the level of deviation from realistic reference conditions, and characterize relevant drivers of diversity loss. Site-specific survey data were consolidated with reference fish community data, and selected biodiversity metrics were calculated and compared for 390 river sections. A novel species deviation index was implemented that reflects the level at which a community deviates from a presumptive natural state. The obtained biodiversity data were cross-linked with environmental factors using generalized linear mixed modeling. A significant decline in biodiversity was revealed when comparing results of the recent surveys with the corresponding reference conditions. Non-native species, transverse structures, and human land use were identified as important drivers of low native species diversity. The deviation index was especially effective in quantifying changes in fish communities and revealed ongoing dynamic environmental influences, such as bioclimatic change, that do not necessarily affect biodiversity metrics but lead to significant deviation from reference conditions. Authorities and stakeholders are encouraged to establish site-specific reference data to develop more targeted species conservation measures.publishe
Adult survival has a stronger role than productivity in the annual population change of European songbirds
No full textBiodiversity is decreasing at an alarming rate, and there is an urgent need to understand the demographic drivers behind population declines. Therefore, it is important to study the different stages of a species’ life cycle, including adult survival and productivity. It is still poorly understood whether adult survival or productivity has a stronger role in population change, and how the role of adult survival and productivity varies spatially in relation to species’ traits. We used bird ringing data from the European Constant Effort Sites (EuroCES) project from the years 2000 to 2021, with 1.2 million captures of 33 songbird species from ten European countries. We investigated the role of productivity and adult survival in annual population change and how it was affected by spatio-climatic gradient (measured as average breeding season temperature per country), migratory strategy (long- vs. short-distance and sedentary birds), and breeding habitat (forest vs. reeds) using linear mixed effect models. Overall, our results show that adult survival is a more important driver of annual population change than productivity within European songbirds. The importance of adult survival and productivity varied spatially, both having a weaker influence in warmer regions. Furthermore, the role of adult survival was stronger for long-distance migrants compared to short-distance migrants. Acknowledging that adult survival has a stronger role in annual population change than productivity can help design more robust conservation actions, especially regarding long-distance migratory songbirds.publishe
Infraestructuras hidraulicas del buen vivir : Observaciones del cronista andino Guaman Poma de Ayala (1615)
No full textpublishe
Bogong moths use a stellar compass for long-distance navigation at night
No full textEach spring, billions of Bogong moths escape hot conditions across southeast Australia by migrating up to 1,000 km to a place that they have never previously visited—a limited number of cool caves in the Australian Alps, historically used for aestivating over summer 1,2 . At the beginning of autumn, the same individuals make a return migration to their breeding grounds to reproduce and die. Here we show that Bogong moths use the starry night sky as a compass to distinguish between specific geographical directions, thereby navigating in their inherited migratory direction towards their distant goal. By tethering spring and autumn migratory moths in a flight simulator 3–5 , we found that, under naturalistic moonless night skies and in a nulled geomagnetic field (disabling the moth’s known magnetic sense 4 ), moths flew in their seasonally appropriate migratory directions. Visual interneurons in different regions of the moth’s brain responded specifically to rotations of the night sky and were tuned to a common sky orientation, firing maximally when the moth was headed southwards. Our results suggest that Bogong moths use stellar cues and the Earth’s magnetic field to create a robust compass system for long-distance nocturnal navigation towards a specific destination.publishe
Factors influencing intergroup encounter dynamics in a wild bonobo population : the untold story of risk, reward and the roots of warfare
No full textIntergroup relationships represent consequential extensions of a social group that not only feedback to shape within-group social relationships and organization, but provide a bridge to the formation of more complex social systems. They range in nature from highly affiliative to lethally agonistic, and can be incredibly variable both within and between animal species. Humans stand out in this regard due to our extreme capacities for both intergroup cooperation that extends beyond kin, and intergroup hostility that extends to large-scale warfare. In a world where news headlines are increasingly dominated by stories of violent conflict, understanding what promotes intergroup tolerance vs. aggression seems especially relevant to understanding the world around us.
Relationships between groups form and change according to intergroup encounter (IGE) dynamics, which encompass when, where, why and how groups interact. These dynamics are influenced by local socioecological conditions; asymmetries in groups’ fighting abilities and/or interaction payoffs; and/or social or genetic ties between groups. In turn, they influence access to resources, which can have short-term energetic consequences, as well as long-term impacts on individual survival and reproductive success. Studies of these dynamics provide valuable insights into the selective forces that structure animal sociality, as well as what incentivizes tolerance and aggression towards outgroup members. To that end, chimpanzees and bonobos are often presented as analogous, dichotomous models of intergroup aggression and tolerance. In short, chimpanzees teach us about the roots of our warlike tendencies while bonobos teach us where our peaceable sides come from. Recent studies in both Pan species have started to blur this dichotomy, revealing that both species exhibit behavioural flexibility during intergroup encounters that may parallel our own.
To better understand the proximate causes of this behavioural flexibility, I integrated socioecological theory with real-world observational data to model IGE dynamics in a population of wild bonobos that exhibits unique behavioural extremes. For my first model, I investigated how different metrics of fruit abundance influence encounter frequency, and showed that rates of encounters track the seasonal abundance of a key food resource rather than overall fruit abundance. These results provide a more nuanced understanding of how fruit abundance influences encounter frequency than previous studies. As part of this investigation, I devised a new method for making spatially-explicit predictions about fruit productivity that can be applied across multiple spatial scales. This investigation also showcased the importance of using consumer-centric methods when modelling how fruit abundance influences animal behaviour. For my second model, I adopted a novel magnet-model approach to investigate how social factors influenced the decision of two parties to interact once they were within earshot. By testing hypotheses that have never been tested in bonobos, I demonstrated that infanticide risk and dispersal-related benefits for females have credible influence on the decisions of two groups to interact. For my third model, I investigated how socioecological factors influence the probability of an aggressive encounter. I found that encounters were more likely to be aggressive when parties from the bonobo group largely responsible for aggression were smaller – a result that completely upends theoretical expectations about imbalances in power. Finally, for my fourth model, I investigated whether winner-loser effects could explain patterns of ‘wins’ and ‘non-wins’ between two groups. I found preliminary evidence for a winner effect and intergroup dominance.
Collectively, results from this thesis provide new insights into what drives behavioural flexibility in one of our closest-living relatives. When synthesized alongside concurrent observations of range expansion and potential lethal aggression, they offer tantalizing evidence for war-like tendencies in a species that often exhibits remarkable outgroup tolerance. This truly shatters the dichotomy of the warrior chimpanzee and peace-loving bonobo. Overall, the work presented here lays the foundation for further investigations about how demography interacts with varying socioecological conditions to facilitate increased intergroup aggression.publishe
The role of aureochromes in transcriptional and circadian regulation
No full textLike most organisms on earth, diatoms are exposed to environmental conditions that regularly change on a daily basis. To anticipate those changes, many organisms have evolved circadian clocks. While it is known that diatoms must possess such circadian clock, very little is known about the molecular mechanism behind it. Two proteins, the bHLH-PAS transcription factor RITMO1 and the dual function photoreceptor/transcription factor PtAUREO1a were implicated as potential clock elements in the mode diatom Phaeodactylum tricornutum. RITMO1 has two paralogs, PtbHLH1b-PAS and PtbHLH2-PAS, while PtAUREO1a has three paralogs, PtAUREO1b, PtAUREO1c and PtAUREO2.
This work focused on the role of PtAUREO1a in the circadian clock and could provide additional evidence that it partakes in circadian regulation. By monitoring the circadian rhythmicity of single-cell chlorophyll fluorescence, it is shown that PtAUREO1a is essential for maintaining rhythmicity under constant (free-running) conditions.
Analyzing transcript rhythmicity analysis in a 24 h entrainment and a 48 h free-running RNA-Seq time series, it was determined that ~60% of the P. tricornutum transcriptome exhibit a rhythmic pattern under entrainment conditions and ~40% of the transcriptome maintain circadian rhythmicity under free-running conditions. The transcriptomic data also suggests that PtAUREO1a knockout (KO) affects the diel expression patterns of a large portion of the transcriptome, including other aureochromes and bHLH-PAS genes. It is shown that the effect of RITMO1 KO on the transcriptome is smaller.
Applying DNA Affinity Purification and Sequencing (DAP-Seq) the genomic DNA binding landscapes of the four aureochrome isoforms of P. tricornutum and their binding motifs are revealed. It is further shown that ~15% of all genes possess a PtAUREO1a binding site in their promotor, a number much lower for the other three aureochromes.
Further, it was attempted to generate a knockout of PtAUREO1b and a double knockout of PtAUREO1a and RITMO1 using the CRISPR/Cas9 system, both of which appear to be lethal, although hypomorphic PtAUREO1a - RITMO1 mutants were generated.
This work provides valuable data for advancing the understanding of the diatom circadian clock while suggesting an essential role of PtAUREO1a in diel and circadian regulation of P. tricornutum as well as a possible feedback loop between PtAUREO1a and RITMO1.publishe
Differential effects of childhood maltreatment types and timing on psychopathology in formerly out-of-home placed young adults
No full textBackground
Childhood maltreatment (CM) increases the risk for psychopathology and CM type, severity and timing are considered important modulating factors in this relationship. However, reported associations are heterogeneous and hardly considered vulnerable groups broadly exposed to CM.
Methods
We investigated the association between CM types and timing and psychopathology in formerly out-of-home placed young adults (N = 185; 32% women, age mean = 26.38 years, SD = 3.49). CM was assessed using the Maltreatment and Abuse Chronology of Exposure Scale. Conditional random forest regression was used to estimate the importance of CM types (abuse, neglect, peer victimization, and sexual abuse), timing (ages 3–18), and global measures (severity, multiplicity, and duration) on adult general, internalizing, and externalizing problems (Achenbach System of Empirically Based Assessment). We validated the results using diagnoses of mental disorders clustered with the Hierarchical Taxonomy of Psychopathology model.
Results
Global CM measures were stronger predictors of internalizing problems than CM type and timing. Abuse in early childhood was a stronger predictor of externalizing problems compared to global CM measures.
Conclusions
Considering CM type and timing might be valuable to guide maltreatment-informed interventions in therapeutic settings.publishe
Data collaboration in digital government research : A literature review and research agenda
No full textSovereign data infrastructures are a central building block of the European Data Strategy, yet little is known about how public administrations share and collaborate on both open and restricted data. This research addresses the gap by systematically analysing the existing literature on data collaboration within the field of digital government research. We thereby make a methodological contribution to digital government research through a rigorous literature review framework that includes Structural Topic Modelling to understand the different themes of the scientific discussion in the field of digital government. We propose an innovative data collaboration framework that includes the ecosystem, the organisational, and the individual levels, enhancing our understanding of the multidimensional nature of data collaboration. Our analysis reveals that while the emphasis is on innovation and participation, critical aspects like standardisation and data management have a declining topic prevalence, despite their importance in developing federated data ecosystems. This comprehensive analysis not only sheds light on the current landscape but also informs a structured research agenda in digital government, aiming to contribute to the advancement of the field.publishe
Structures in Arbitrary Object Theory
No full textThis article critically compares two approaches that seek to explain ante rem mathematical structures in terms of arbitrary objects. The first is a theory that was developed by Kit Fine, and the second is a view that was more recently developed by me. I make a plea for a synthesis between the two approaches.publishe
Discriminatory coercion : Understanding the biases of EU and US sanctions
No full textThis article examines the biases the two most important senders of economic sanctions, the European Union and the United States, frequently introduce into their coercive measures. Distinguishing between sanction incidence and intensity, our study identifies the conditions under which the two senders over- or under-sanctioned their targets during the post-Cold War era. Theoretically, we conceive of the executive branch of the two senders as opportunistic actors that balance the influence of special economic interests against the preference of the average citizen and the lobbying of public interest groups. We expect that senders shy away from harsh measures against allies and former colonies and that private interest groups try to prevent the imposition of strong sanctions that potentially harm their members’ business. However, strong diasporas from the target state and violations of core liberal values should increase the chance of forceful measures. Our examination of the post-Cold War era supports our demand- and supply-side analysis of the Western powers’ biased coercion. The measures of the two senders are often strikingly similar, reflecting the strong influence of the sanction bureaucracies of the two senders. However, a notable difference is that the EU imposes lighter measures against economically powerful targets. Counterfactual simulations demonstrate that the EU measures against Russia and the US sanctions against China have been repeatedly too weak during the post-Cold War era.publishe