Thünen Institute
  • Braunschweig, Germany
Recent publications
This study investigates the economic, social, and environmental impacts of dust storms on pastoralists' livelihoods in the Chaqakdo rangeland of West Iran. Data was collected through face-to-face interviews with 100 pastoralists in 2019. The research adopts a quantitative approach using Structural Equation Modeling (SEM). The results demonstrate a significant and positive relationship between pastoralists' livelihoods and the three independent variables (environmental, economic, and social), with the strongest correlation observed in environmental factors. The path coefficients indicate positive effects on pastoralists' livelihoods. Additionally, dust storms were found to have detrimental environmental effects, such as plant leaf pollution, reduced grazing, and decreased growth of grassland plants. Therefore, it is crucial to establish adaptive measures to mitigate the impacts of dust storms on pastoralists, considering their heavy reliance on the local pastures.
While the bioeconomy permeates all sectors, respective markets are subject to different dynamics. Markets for bio‐based amino acids and insect biomass illustrate this. The global and EU markets for bio‐based amino acids are well‐established and growing. However, the increase in production in the EU of some ‘new’ amino acids is much smaller than the decrease in production of well‐established lysine and threonine that has resulted from the relocation of the production of these amino acids from the EU to Asia (an effect of higher production costs and stricter environmental standards in the EU). The result is that overall production of amino acids has decreased significantly. The market for insect biomass is just emerging in the EU. Production is low, but companies are starting to upscale. The animal feed market is a major target market for free amino acids and insect biomass. Free amino acids are classified as feed additives and placing them on the feed market is costly. Insect meal is a feed material and placing it on the market is quite straightforward, although its use in feed for poultry and pigs was approved only in September 2021. Free amino acids are common ingredients of animal feed, but their use is prohibited in organic farming. The use of insect meal in organic farming is not prohibited, but a corresponding certification is not yet developed in the EU.
Understanding individual growth in commercially exploited fish populations is key to successful stock assessment and informed ecosystem‐based fisheries management. Traditionally, growth rates in marine fish are estimated using otolith age‐readings in combination with age‐length relationships from field samples, or tag‐recapture field experiments. However, for some species, otolith‐based approaches have been proven unreliable and tag‐recapture experiments suffer from high working effort and costs as well as low recapture rates. An important alternative approach for estimating fish growth is represented by bioenergetic modelling which in addition to pure growth estimation can provide valuable insights into the processes leading to temporal growth changes resulting from environmental and related behavioural changes. We here developed an individual‐based bioenergetic model for Western Baltic cod (Gadus morhua), traditionally a commercially important fish species that however collapsed recently and likely suffers from climate change effects. Western Baltic cod is an ideal case study for bioenergetic modelling because of recently gained in‐situ process knowledge on spatial distribution and feeding behaviour based on highly resolved data on stomachs and fish distribution. Additionally, physiological processes such as gastric evacuation, consumption, net‐conversion efficiency and metabolic rates have been well studied for cod in laboratory experiments. Our model reliably reproduced seasonal growth patterns observed in the field. Importantly, our bioenergetic modelling approach implementing depth‐use patterns and food intake allowed us to explain the potentially detrimental effect summer heat periods have on the growth of Western Baltic cod that likely will increasingly occur in the future. Hence, our model simulations highlighted a potential mechanism on how warming due to climate change affects the growth of a key species that may apply for similar environments elsewhere.
Livestock farming is one of the main sources of greenhouse gas emissions. In Europe, the agricultural sectors of Ireland and Denmark are the most livestock-intensive. Based on a scenario analysis using the CGE model MAGNET, this study estimates the effects of dietary changes toward the recommendations of the EAT-Lancet Commission in Europe on the agricultural sector of Ireland and Denmark. Results show that full adoption of the diet leads to significant reductions in agricultural emissions, particularly methane, with potential emission savings of 26.4% or 5.4 Mt CO2-equivalent in Ireland and 21.7%, or 1.9 Mt CO2-equivalent in Denmark. Global agricultural emissions can be reduced by 2.4% or 193.7 Mt CO2-equivalent. However, income losses are observed in livestock production, which are offset to varying degrees by gains in horticulture and trade dynamics, leading to different outcomes across regions. Policymakers should promote plant-based diets and monitor export dynamics to achieve effective emission reductions. Additionally, methane mitigation strategies should be integrated into climate plans. This study highlights the need for further research on country-specific environmental impacts and trade-offs associated with dietary changes.
Soil organic carbon (SOC) dynamics are vital in the context of climate change and sustainable soil management. The ẟ13C signatures of SOC are powerful indicators and tracers of C fluxes through soils and of transformation processes within soils. Depth gradients of ẟ13C can be considered as their archive. However, many different drivers and processes impact ẟ13C signatures of SOC simultaneously, thus hampering their interpretation. Here we summarize the current knowledge about drivers, processes and C sources determining the δ13C signatures of organic matter along soil profiles. The largest ẟ13C gradients within soil profiles (> 10‰) have been observed at sites where vegetation has shifted between C3 and C4 plants, thus changing the isotopic signatures of C inputs. In soil profiles without such vegetation changes, the δ13C signatures typically increase by 1–3‰ from topsoil to subsoil. Three main reasons for this are (i) the decreasing ẟ13C of atmospheric CO2 (Suess effect) has led to a depletion in plant biomass by about 2.0‰ since 1850, (ii) increasing atmospheric CO2 concentrations have also depleted plant biomass by about 1.8‰, and (iii) isotopic fractionation occurs during continuous microbial C recycling and necromass accumulation. Moreover, a greater mobility of 13C-enriched hydrophilic dissolved organic C and other C input sources may impact ẟ13C gradients in soils. External drivers, such as climatic and atmospheric changes, affect the ẟ13C signature of C inputs, and have stronger and increasing influence on ẟ13C gradients in soil profiles compared to soil internal processes.
Background The lack of water is a major constraint for microbial life in hyperarid deserts. Consequently, the abundance and diversity of microorganisms in common habitats such as soil are strongly reduced, and colonization occurs primarily by specifically adapted microorganisms that thrive in particular refugia to escape the harsh conditions that prevail in these deserts. We suggest that plants provide another refugium for microbial life in hyperarid deserts. We studied the bacterial colonization of Tillandsia landbeckii (Bromeliaceae) plants, which occur in the hyperarid regions of the Atacama Desert in Chile, one of the driest and oldest deserts on Earth. Results We detected clear differences between the bacterial communities being plant associated to those of the bare soil surface (PERMANOVA, R² = 0.187, p = 0.001), indicating that Tillandsia plants host a specific bacterial community, not only dust-deposited cells. Moreover, the bacterial communities in the phyllosphere were distinct from those in the laimosphere, i.e., on buried shoots (R² = 0.108, p = 0.001), indicating further habitat differentiation within plant individuals. The bacterial taxa detected in the phyllosphere are partly well-known phyllosphere colonizers, but in addition, some rather unusual taxa (subgroup2 Acidobacteriae, Acidiphilum) and insect endosymbionts (Wolbachia, “Candidatus Uzinura”) were found. The laimosphere hosted phyllosphere-associated as well as soil-derived taxa. The phyllosphere bacterial communities showed biogeographic patterns across the desert (R² = 0.331, p = 0.001). These patterns were different and even more pronounced in the laimosphere (R² = 0.467, p = 0.001), indicating that different factors determine community assembly in the two plant compartments. Furthermore, the phyllosphere microbiota underwent temporal changes (R² = 0.064, p = 0.001). Conclusions Our data demonstrate that T. landbeckii plants host specific bacterial communities in the phyllosphere as well as in the laimosphere. Therewith, these plants provide compartment-specific refugia for microbial life in hyperarid desert environments. The bacterial communities show biogeographic patterns and temporal variation, as known from other plant microbiomes, demonstrating environmental responsiveness and suggesting that bacteria inhabit these plants as viable microorganisms. 1mJ_tDG7agf2H2TZP3DsmgVideo Abstract
This article presents models to predict the time until mechanical failure of in-ground wooden test specimens resulting from fungal decay. Historical records of decay ratings were modelled by remotely sensed data from ERA5-Land. In total, 2,570 test specimens of 16 different wood species were exposed at 21 different test sites, representing three continents and climatic conditions from sub-polar to tropical, spanning a period from 1980 until 2022. To obtain specimen decay ratings over their exposure time, inspections were conducted in mostly annual and sometimes biannual intervals. For each specimen's exposure period, a laboratory developed dose-response model was populated using remotely sensed soil moisture and temperature data retrieved from ERA5-Land. Wood specimens were grouped according to natural durability rankings to reduce the variability of in-ground wood decay rate between wood species. Non-linear, sigmoid-shaped models were then constructed to describe wood decay progression as a function of daily accumulated exposure to soil moisture and temperature conditions (dose). Dose, a mechanistic weighting of daily exposure conditions over time, generally performed better than exposure time alone as a predictor of in-ground wood decay progression. The open-access availability of remotely sensed soil-state data in combination with wood specimen data proved promising for in-ground wood decay predictions.
The European Deforestation Regulation 2023/1115 (EUDR) prohibits trading of wood and wood products obtained from illegal logging on the EU market. While the identification of solid wood via anatomy, chemistry and genetics has already been established, there is a lack of identification methods for pulp and paper that complement anatomy. This publication presents a newly developed chemotaxonomic method for identifying mixed tropical hardwood (MTH) species in pulp and paper products based on their extractives analyzed with thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). The measured data was processed and compared to identify marker substances and was then merged into a fingerprint database for identifying MTH species in paper of unknown composition. As database references, fully bleached kraft pulps were produced from 38 anatomically identified wood samples and then cryo-ball milled and extracted successively with n -hexane and acetone. The results show that the remaining wood extractives generated from bleached pulps are specific enough to find chemical relevant marker substances to detect MTH species. As chemical composition and anatomy are independent characteristics of wood, this paper makes a completely independent method available, which potentially improves the screening for Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) protected species.
Coarse woody debris (CWD) is a major component of the ecosystem carbon (C) balance. The estimation of C storage in CWD is an important element of the German greenhouse gas (GHG) reporting of forests, which is mainly based on the German National Forest Inventory. The deadwood C stock is calculated based on deadwood volume and, according to deadwood density (DD) and carbon concentration (CC) for each decay class (DC). Yet, the data basis of DD and CC per DC for above-ground CWD is still insufficient since there are very few country-specific measurements. Values from literature provide a first approximation for national-level estimates. However, different DC systems often prevent the use of DD and CC of other countries. Therefore, we developed a conversion method for harmonization of these data with the German four-class system. Following this, we conducted a meta-analysis to calculate mean DD and CC values for the main Central European tree species and to assess their variation. Significantly lower DDs were observed with increasing DC, except for beech between DC 3 and 4. Compared to spruce and pine, DD of beech CWD was significantly higher, overall as well as in DC 1 and 2. Species became similar in DD in advanced decay stages. A maximum of 92% of the variation in DD could be explained mainly by DC, CWD type, tree species and their interaction. DD values were mostly higher than current values in GHG reporting. CC increased with increasing DC in spruce and pine and was higher than in beech CWD, where no variation was detected. About 86% of the variation in CC could be explained mainly by DC, tree species and their interactive effect. The default value of 50% employed by the Intergovernmental Panel on Climate Change might under- (spruce, pine) and/or overestimate (spruce, pine, beech) the real CC depending on DC by up to 3.4 (pine) and/or 4.2% (beech). Based on our calculated mean DD and CC values, the accuracy of C stock assessment in deadwood as part of the GHG reporting for Germany can be substantially improved.
Environmental factors can cause cancer in both wild animals and humans. In ecological settings, genetic variation and natural selection can sometimes produce resilience to the negative impacts of environmental change. An increase in oncogenic substances in natural habitats has therefore, unintentionally, created opportunities for using polluted habitats to study cancer defence mechanisms. The Baltic and North Sea are amongst the most contaminated marine areas, with a long history of pollution. Two flatfish species (flounder, Platichthys flesus and dab, Limanda limanda) are used as ecotoxicological indicator species due to pollution-induced liver cancer. Cancer is more prevalent in dab, suggesting species-specific differences in vulnerability and/or defence mechanisms. We conducted gene expression analyses for 30 flatfishes. We characterize between- and within-species patterns in potential cancer-related mechanisms. By comparing cancerous and healthy fishes, and non-cancerous fishes from clean and polluted sites, we suggest also genes and related physiological mechanisms that could contribute to a higher resistance to pollution-induced cancer in flounders. We discovered changes in transcriptome related to elevated pollutant metabolism, alongside greater tumour suppression mechanisms in the liver tissue of flounders compared to dabs. This suggests either hormetic upregulation of tumor suppression or a stronger natural selection pressure for higher cancer resistance for flounders in polluted environment. Based on gene expression patterns seen in cancerous and healthy fish, for liver cancer to develop in flounders, genetic defence mechanisms need to be suppressed, while in dabs, analogous process is weak or absent. We conclude that wild species could offer novel insights and ideas for understanding the nature and evolution of natural cancer defence mechanisms.
Recreational fisheries catches are increasingly considered in the assessment and management of mixed recreational-commercial marine fisheries, while the contribution of recreational fisheries to the economy is often overlooked. Using a telephone diary survey targeting marine recreational anglers in Germany, we estimated the number of anglers and their expenditures over the course of 1 year (2014–2015). About 197,000 marine anglers spent €248 million in Germany. We then constructed regional input–output models and contrasted the economic impacts of resident and nonresident anglers fishing in coastal and transitional brackish waters of the state of Mecklenburg-Western Pomerania in north-eastern Germany. On a regional scale, the total economic impact was €210 million supporting 2044 jobs, nonresident anglers were responsible for eight times greater economic impact than resident anglers. Maintaining attractive fishing opportunities for the recreational fishing sector, specifically angling tourism, is critical for maintaining resource flows to local and regional economies.
Background: Peroxisome proliferator-activated receptor-gamma (PPAR-γ) plays a crucial role in regulating lipid and glucose metabolism, cancer, and inflammation, making it an attractive target for drug development. Meanwhile, β-Carotene, known for its antioxidant, anticancer and antiinflammatory properties, holds promise for modulating PPAR-γ activity. Understanding their interaction is crucial. Objective: This study aims to explore the therapeutic potential of β-carotene in modulating PPAR-γ activity by investigating their binding interactions. Objective To explore the potential therapeutic applications of β-carotene in modulating PPAR-γ activity, it is of great interest to comprehend the binding interactions between PPAR-γ and β-carotene. Methods: Screening of bioactive compounds from PubChem was conducted using GlideXP to identify potential PPAR-γ (PDB: 2PRG) ligands. During this screening, both protein and bioactive compounds were prepared following established protocols. Subsequently, the compounds were docked into the ligand binding domain (LBD) of the protein using XP docking. Rosiglitazone was used as an internal control. β-Carotene emerged as a lead based on Lipinski’s rule, docking score, free energy, and LBD interactions. Molinspiration analysis assessed its drug likeness. Molecular dynamics (MD) simulations utilizing Desmond with OPLS 2005 force field were employed to examine the dynamics and stability of the PPAR-γ/β-carotene complex. Results: β-carotene had strong hydrophobic interactions with specific residues within the ligandbinding domain of PPAR-γ. The calculated binding affinity (-9.07 kcal/mol) indicated a strong interaction between β-carotene and PPAR-γ, suggesting that β-carotene may modulate the activity of PPAR-γ. On a time scale of 100 ns, the MD simulations provided insights into the conformational changes, flexibility, and intermolecular interactions within the complex. Conclusion: In silico docking and dynamics simulation analyses show that PPAR-γ and β-carotene can form a stable complex, suggesting potential implications for metabolic modulation.
Land‐use intensification in grassland ecosystems (i.e. increased mowing frequency, intensified grazing) has a strong negative effect on biodiversity and ecosystem services. However, accurate information on grassland‐use intensity is difficult to acquire and restricted to the local or regional level. Recent studies have shown that mowing events can be mapped for large areas using satellite image time series. The transferability of such approaches, especially to mountain areas, has been little explored, however, and the relevance for ecological applications in biodiversity and conservation has hardly been investigated. Here, we used a rule‐based algorithm to produce annual maps for 2018–2021 of grassland‐management events, that is, mowing and/or grazing, for Switzerland using Sentinel‐2 and Landsat 8 satellite data. We assessed the detection of management events based on independent reference data, which we acquired from daily time series of publicly available webcams that are widely distributed across Switzerland. We further examined the relationships between the generated grassland‐use intensity measures and plant species richness and ecological indicator values derived from a nationwide field survey. The webcam‐based verification for 2020 and 2021 revealed that most detected management events were actual mowing/grazing events (≥78%), but that a substantial number of events were not detected (up to 57%), particularly grazing events at higher elevations. We found lower plant species richness and higher mean ecological indicator values for nutrients and mowing tolerance with more frequent management events and those starting earlier in the year. A large proportion of the variance was explained by our use‐intensity measures. Our findings therefore highlight that remotely assessed management events can characterise land‐use intensity at fine spatial and temporal resolutions across broad scales and can explain plant biodiversity patterns in grasslands.
Molecular responses to drought stress have been mainly studied in deciduous tree species although conifers dominate boreal forests. Here, we analysed the transcriptional response of Picea abies (L.) H. Karst. needles after exposure to severe drought by quantitative RNA-sequencing. In total, 2,402 differentially expressed genes (DEGs) were identified, of which 1,186 were up- and 1,216 downregulated. The upregulated DEGs are mainly involved in responses to stress, nitrogen compound, water deprivation, and abscisic acid as well as in channel activity. Although only one bZIP was identified among the DEGs, several other transcription factors involved in ABA-dependent pathways such as MYB, bHLH and WRKY showed differential expression. AP2/EREBP transcription factors related to ABA-independent pathways were also identified as DEGs. A functional interaction network of the 40 most connected Arabidopsis thaliana homologs of all Picea abies DEGs placed the two top-hubs P5CS1 and P5CS2 in the center. P5CS1 is the key enzyme in the biosynthesis of proline known to be accumulated in plants under abiotic stress. Lignin synthesis and DNA-related processes, among others, are overrepresented in this network. Our data highlight interesting gene targets for functional studies and natural genetic variation analyses to support the future identification and selection of potential drought tolerant trees.
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566 members
Jan Thiele
  • Institute of Biodiversity
Andreas Klärner
  • Institute of Rural Studies
Tanja G M Sanders
  • Institute of Forest Ecosystems
Stefan Erasmi
  • Institute of Farm Economics
Christian Bruemmer
  • Institute of Climate-Smart Agriculture
Bundesallee 50, 38116 , Braunschweig, Germany
Head of institution
Folkhard Isermeyer