Research

MSc Thesis: Effects of large-scale forest fires on insular bats

Wildfires have historically affected wildlife. However, over the last decades the intensity and severity of wildfires has considerably increased, further threatening a wide array of species and ecosystems already impacted by multiple anthropogenic threats. Vegetation structure and composition is highly impacted by forest fires which in turn impacts vertebrate communities, including bats. However, detailed knowledge about the effects of fires on the activity and occurrence of island bats is lacking, which hampers the conservation and management in fire-prone ecosystems. Madeira Island is home to three insectivorous bat species: Nyctalus leisleri verrucosus (endemic subspecies to Madeira), Pipistrellus maderensis (IUCN Vulnerable, endemic species to Macaronesia) and Plecotus austriacus, each representing one of the three main foraging guilds of insectivorous bats (open space foragers, edge space foragers, and narrow space foragers, respectively). The aim of this project was to evaluate how island insectivorous bats are affected by large-scale fires, using Madeira Island as a case study. In the summer of 2016 - during which Madeira was hit by multiple large wildfires - we conducted an island-wide bioacoustic bat survey. Here, we investigate the responses of Madeiran bats to the 2016 fires by resurveying 33 burned and 25 unburned sites, five years after the occurrence of the fires. We found an overall decline in bat activity and species-specific responses to post-fire vegetation. Moreover, we found that in 2016 bat activity was consistently lower in burned sites than in unburned sites, while in 2021 the activity of all species increased in sites that had been burned five years ago. Our results thus suggest species- and guild-specific responses to post-fire vegetation. Nyctalus leisleri verrucosus, an open space forager, exhibited a greater increase in activity in burned areas than Plecotus austriacus, a narrow space forager. Furthermore, our results show that specific habitat types such as forests and woodlands play an important role in the activity, foraging and social behavior of bats. This study provides key insights into the spatiotemporal effects of large-scale fires on insular bats. Identification of changes in the spatiotemporal activity levels of island-dwelling bats and their response to post-fire vegetation is important for the implementation of management and conservation strategies. Considering that ca. 60% of all bat species occur on islands, and ca. 25% are insular endemics, more such studies are needed, especially in anticipation of the increase in such extreme events that are likely to occur more frequently under future climate conditions. (Available on ResearchGate Link in picture)

MSc Research Project: Petri dish ecology - Screening interaction between microorganism associated to the ambrosia beetle Xyleborinus saxesenii and its galleries

Among ambrosia beetles, the most widespread group belongs to the genus Xyleborini, with X. saxesenii probably being the most widespread species worldwide. In recent decades, especially in Europe, the intensity and severity of economic damage caused by this beetle species has increased considerably. These beetles are particularly dependent on the composition of their microbiome and especially on the fungus species Raffaelea sp. with which they live in symbiosis. However, there is a lack of detailed knowledge about the composition of the microbiome in the galleries as well as in the glands of the beetles themselves, and the role of the interactions of the individual components (fungi and bacteria) in the microbiome in promoting the spread and damage of the beetles. The aim of this project was to investigate the interactions of the fungal isolates from galleries and elytra of the beetles, looking at additional side experiments of the interactions with the bacterial isolates. Here we investigate the interactions of the different fungi between each other, as well as their morphology and growth rates in different bioassays. We generally found that Raffaelea sufurea, the main symbiont of X. saxeesenii, has one of the highest growth rates. In addition, it seems to inhibit the growth of pathogenic fungi species such as Aspergillus, Penicillium and Cheatomium. Furthermore, it changes its morphology when in contact with alcohol. Our results thus suggest that Raffaelea sufurea fungi actively inhibit the growth of the beetle as well as their own. The morphological change in contact with alcohol suggests that ambrosia fungi are resistant to the cytotoxin ethanol, a constituent of freshly dead wood. The structure and position of the mycetangia on the body seems to have a selective effect on the ambrosia fungus associated with the beetle species. In addition, the first experiments with the isolated bacteria indicate that they have an important role in the fungus cultivation by the beetles. This study provides important insights into the interactions of the different fungal groups in the beetle species X. saxesenii. The identification of changes in growth and testing of these microbial communities supports sampling for significant statistical tests to further hypotheses about symbiotic associations as well as antibiotic responses in the environment.

HiWi at ConFoBi (Conservation of Forest Biodiversity in Multiple-Use Landscapes of Central Europe): Bats and forest structures (Project B5)

Work experience as a research assistant in the DFG-funded research training group ConFoBi ("Conservation of Forest Biodiversity in Multiple-Use landscapes of Central Europe") in the project B5 ("Landscape-moderated use of forest structures by bats"). I was responsible for the following tasks: working in the field, monitoring and maintaining equipment for the automated acoustic recording of bat calls, the processing and evaluation of data, the identification of bat species and their frequency based on the the recorded calls, logging of reports and preparation of reports.

BSc Thesis: The frequency of social calls of the bat genus Pipistrellus in relation to forest structure and temperature

Many forest use concepts for timber production elicit conflicts with the protection of biological diversity. Therefore, it is a special challenge to reduce these conflicts. In this work, bats of the genus Pipistrellus are used as indicators for forest structures and complexity. The aim of this work is to examine whether the local availability of dead wood can explain the intensity of bat activity, based on the frequency of social calls of the genus Pipistrellus. The influencing factors include the forest type, the total number of trees, the amount of deadwood and the proportion of dead wood, as well as the temperature and the months in which the records were taken. At 135 retention sites under investigation in the Black Forest,
the relation between frequency of social calls and forest structures were investigated without relevant results. Generalized linear models were used to model the data. There was a relevant reference to temperature fluctuations, which is due to the bat life cycle. Social activities are highest in autumn due to the mating season. The results showed that all methods had limitations and that the presence of roosting sides would have to be checked to complete a comprehensive data collection.

BSc Research Project - Universidad Austral de Chile: Dung beetles (Scarabaeidae: Scarabaeinae) as bio-indicators of diversity in native forest, plantation and natural grasslands

Translated from spanish: Despite the great geological differences that exist in Chile, it is accompanied by a unique biodiversity of flora and fauna due to its particular climate and geography, however there are few studies on its ecology. Intensive land use such as agriculture and plantation forestry determines the environment today, and is the main reason for the decrease in biological diversity. The species composition and community richness of dung beetle species are dependent on the density of grazing, the species of grasses and the history of use of a grazing area or forest; they are also factors in the biodiversity of a habitat, determine the whole and thus reflect the actual degree of nature protection. On the basis of current knowledge about this group of insects, which are characterised as indicators for local environmental developments, the main objective was to evaluate dung beetles as bioindicator insects in three different environments, native forest, grassland and plantation, located in the Arboretum of the city of Valdivia in Chile.

BSc Reaseach Project: Wasps detect pyrrolizidine alkaloid and whether wasps are subsequently repellent to it using the example of Creatonotos transiens

As part of a project study "entomological project work", the aim was to work out "how wasps detect pA and whether wasps subsequently repeat pA using the example of Creatonotos transiens". Based on thirty bait sites, the weather, the daily time of day and the daily air temperature, the best bait sites could be determined in phase one of the experiment at the Forest Zoological Institute, Stegen-Wittental branch of the Albert Ludwigs University of Freiburg. After five different methodological strategies at the best bait site, taking into account the weather, air temperature and time of day in phase two of the study, the result was that wasps detect pA due to feeding and are subsequently repellent from it.