Browsing by Person "Frank, Jonas"

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Disc mower versus bar mower: Evaluation of the direct effects of two common mowing techniques on the grassland arthropod fauna
(2025) von Berg, Lea; Frank, Jonas; Betz, Oliver; Steidle, Johannes L. M.; Böttinger, Stefan; Sann, Manuela; von Berg, Lea; Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology, University of Tübingen, Tübingen, Germany; Frank, Jonas; Fundamentals of Agricultural Engineering, Institute for Agricultural Engineering, University of Hohenheim, Stuttgart, Germany; Betz, Oliver; Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology, University of Tübingen, Tübingen, Germany; Steidle, Johannes L. M.; Chemical Ecology, Institute for Biology, University of Hohenheim, Stuttgart, Germany; Böttinger, Stefan; Fundamentals of Agricultural Engineering, Institute for Agricultural Engineering, University of Hohenheim, Stuttgart, Germany; Sann, Manuela; Chemical Ecology, Institute for Biology, University of Hohenheim, Stuttgart, Germany
1. In Central Europe, species‐rich grasslands are threatened by intensive agriculture with frequent mowing, contributing to the reduction of arthropods such as insects and spiders. However, comprehensive and standardised studies on the direct effects of the two most agriculturally relevant mowing techniques, e.g., double‐blade bar mower versus disc mower, are lacking. 2. In a 2‐year experiment, we have investigated the direct effect of mowing on eight abundant arthropod groups in grassland, covering two seasonal mowing events in both years, using a randomised block design. We compared (a) an unmown control, (b) a double‐blade bar mower and (c) a disc mower. 3. For most of the taxonomic groups studied, a significantly lower number of individuals was found in the experimental plots immediately after mowing, regardless of the mowing technique, compared to an unmown control. This was not the case for Orthoptera and Coleoptera, which did not show a significant reduction in the number of individuals for both mowing techniques (Orthoptera) or only for the double‐blade bar mower (Coleoptera). 4. Between both mowing techniques, no significant differences were found for all taxonomic groups investigated. 5. Synthesis and applications: Our findings suggest that mowing in general has a negative impact on abundant arthropod groups in grassland, regardless of the method used. Tractor‐driven double‐blade bar mowers do not seem to be a truly insect‐friendly alternative to a conventional disc mower. Other factors such as cutting height and mowing regimes should be seriously considered to protect spiders and insects from the negative effects of mowing. In addition, we strongly recommend the maintenance of unmown refugia. Insects and spiders that are spared by mowing can take refuge in these unmown areas to avoid subsequent harvesting and thermally unfavourable conditions that arise on mown areas. Further, unmown refugia are basic habitat structures for a subsequent recolonisation of mown areas once the flora has recovered.
DIY Insektenscheuche
Konzept und Umsetzung im Projekt InsectMow
(2024) Frank, Jonas
Quick guide to building the insect flushing bar from the InsectMow project
The effect of culture on trade over time
new evidence from the GLOBE data set
(2018) Frank, Jonas
In this essay I use the GLOBE research study by House et al. (2013) as a proxy for measuring cultural distance. Unlike other studies, GLOBE introduces nine cultural dimensions and focuses exclusively on managers, allowing for a distinct glimpse into the values of people actually making trade decisions. I make use of a state-of-the-art PPML approach using data on international trade flows together with intra-national trade flows (Yotov, 2012) and a comprehensive set of fixed effects to consistently es- timate a gravity equation using a panel from 1995 to 2004. I distinguish between different industries by following the goods classiffcation introduced by Rauch (1999). The results show that cultural differences indeed affect trade values differently over time, but their size and impact depends on the chosen measure of cultural distance and on the industry classification.
The effects of economic sanctions on trade
new evidence from apanel PPML gravity approach
(2018) Frank, Jonas
Economic sanctions are a popular diplomatic tool for countries to enforce political demands abroad or to punish non-complying countries. There is an ongoing debate in the literature about whether this tool is effective in reaching these goals. This paper looks at the consequences of sanctions for bilateral trade values between 1987 and 2005. In order to quantify the direct effects of sanctions on the trade flows between countries I use PPML as well as several other econometric specifications to estimate the gravity equation with country pair, sender-time, and target-time fixed effects. Following Heid et al. (2015) I include intra-national as well as international trade flows, to reduce the endogeneity bias of trade policy instruments. The estimates reveal that there is a signifucant decrease in the value of trade after the introduction of sanctions, which turns out to be driven by moderate sanctions. I also check whether countries that are affected by sanctions switch to other trade partners, but here is no robust evidence for behavior like this.
The trade effects of cultural distance and economic sanctions
a structural gravity approach
(2018) Frank, Jonas; Jung, Benjamin
In this doctoral thesis, I set out to empirically analyze the impact of different trade barrieres on the value of bilateral trade by means of a structural gravity approach.