Biology subjects

Muehlbauer, M.

Publications and source records attributed to Muehlbauer, M..

3 recordsLinked to original sources

bioRxiv2025

Why they occur here but not there - a case study of Great Spotted Woodpeckers in the city of Munich

O_LIMany animal species can occur in the urban environment. The factors determining whether a particular species can live in a particular place in the city are, however, often not known. Such knowledge is needed to be able to design a built environment that is suitable for species. C_LIO_LIThe Great Spotted Woodpecker, Dendrocopos major, breeds in self-made cavities in trees and regularly occurs in cities. Here, we used a number of approaches to elucidate the factors that influence the occurrence of woodpeckers in the build-up area of the city. C_LIO_LIWe studied the occurrence of D. major on 103 squares in Munich, Germany and linked their presence to a number of square features such as square size, position in the city, tree occurrences, and a number of other variables. We also observed the presence of woodpecker cavities and undertook behavioural observations to study tree use. C_LIO_LIWoodpeckers were observed on 60% of the squares. A random forest model showed that the number of humans on squares negatively affected woodpecker occurrence, while a number of tree-related variables, such as tree density, tree diversity, the number of old trees (>60 cm DBH), and the sum of DBH of trees on the square, positively affected occurrence. Some other variables were also important, such as the amount of green in the surroundings and the distance to the city centre. C_LIO_LINests were found only in trees with a DBH>20 cm, and there was a distinct preference for larger trees, whereby a range of species was accepted. Behavioural observations showed that woodpeckers used a wide variety of trees, including small ones. Particular species and trees with a DBH>20 cm are preferred. C_LIO_LIOur study shows that humans can design public places for the presence of the Great Spotted Woodpecker by providing a locally high abundance of trees of different species with total DBH close to 25m. Trees in the surroundings and the presence of softwood trees with >40 cm will make it more likely that woodpeckers will use such sites in the city. C_LI Statement on inclusionOur study brings both established scientists with permanent faculty positions with Ph.D.-students and students of the 2nd year of their B.Sc.-studies or 1st or 2nd year of their M.Sc.-studies for whom this work is the first experience in the publication of scientific results. Students were particularly encouraged to contribute to question and hypothesis development as well as analysis and interpretation.

ecology↗

bioRxiv2023

Connectivity at home: A data-driven connectivity modeling framework for home range movements in heterogeneous landscapes

The landscape connectivity of cities is increasingly recognized as crucial for biodiversity conservation and ecosystem services. Yet, modelling ecological connectivity in cities remains challenging because landscape resistance is often based on expert judgment rather than empirical evidence, leading to varying modelling results and limited use for planning. We developed and tested a data-driven framework for empirically parametrizing resistance and movement-distance parameters in functional connectivity models from movement-proxy data - information on the presence/absence of animal movement from direct observation or camera traps. At each step, we ensured that the connectivity model reflected the behavioural and spatial properties of the observations. We applied the framework for the common blackbird (Turdus merula) in Munich, Germany. We used observations of flying blackbirds as movement-proxy data in a logistic regression framework, testing alternative combinations of resistance and movement distances. Model selection identified the parameter sets best supported by the data. The resulting parameters were validated using repeated out-of-sample validation and compared against an expert-based connectivity model. Connectivity derived from empirically estimated parameters increased the probability of observing flying blackbirds. Across repeated validations, the empirical model achieved a mean AUC of 0.76 and R2 of 0.17. It performed moderately better than the expert-based model. Depending on their height, buildings exhibited varying resistance to flying blackbirds. Results indicate that expert assessments may oversimplify urban barriers. The approach provides a transparent, reproducible framework for using movement-proxy data to derive maps of landscape resistance. It offers a step toward more data-driven urban connectivity modelling.

ecology↗

bioRxiv2017

Structural basis for terminal loop recognition and processing of pri-miRNA-18a by hnRNP A1

Post-transcriptional mechanisms play a predominant role in the control of microRNA (miRNA) production. Recognition of the terminal loop of precursor miRNAs by RNA-binding proteins (RBPs) influences their processing; however, the mechanistic and structural basis for how levels of individual or subsets of miRNAs are regulated is mostly unexplored. We previously described a role for hnRNP A1, an RBP implicated in many aspects of RNA processing, as an auxiliary factor that promotes the Microprocessor-mediated processing of pri-mir-18a. Here, we reveal the mechanistic basis for this stimulatory role of hnRNP A1 by combining integrative structural biology with biochemical and functional assays. We demonstrate that hnRNP A1 forms a 1:1 complex with pri-mir-18a that involves binding of both RNA recognition motifs (RRMs) to cognate RNA sequence motifs in the conserved terminal loop of pri-mir-18a. Terminal loop binding induces an allosteric destabilization of base-pairing in the pri-mir-18a stem that promotes its down-stream processing. Our results highlight terminal loop RNA recognition by RNA-binding proteins as a general principle of miRNA biogenesis and regulation.

molecular biology↗