Refine
Year of publication
Document Type
- Doctoral Thesis (23) (remove)
Keywords
- Biodiversität (2)
- Pestizid (2)
- 1H-NMR Relaxometry (1)
- Amphibia (1)
- Aquatic Ecotoxicology (1)
- Bedrohte Tiere (1)
- Benetzung (1)
- Bestäubung (1)
- Biodiversity (1)
- Biogasanlage (1)
Institute
- Institut für Umweltwissenschaften (23) (remove)
Vertebrate biodiversity is rapidly decreasing worldwide with amphibians being the most endangered vertebrate group. In the EU, 21 of 89 amphibian species are recognized as being endangered. The intensively used European agricultural landscape is one of the major causes for these declines. As agriculture represents an essential habitat for amphibians, exposure to pesticides can have adverse effects on amphibian populations. Currently, the European risk assessment of pesticides for vertebrates requires specific approaches for fish regarding aquatic vertebrate toxicity and birds as well as mammals for terrestrial vertebrate toxicity but does not address the unique characteristics of amphibians. Therefore, the overall goal of this thesis was to investigate the ecotoxicological effects of pesticides on Central European anuran amphibians. For this, effects on aquatic and terrestrial amphibian life stages as well as on reproduction were investigated. Then, in anticipation of a risk assessment of pesticides for amphibians, this thesis discussed potential regulatory risk assessment approaches.
For the investigated pesticides and amphibian species, it was observed that the acute aquatic toxicity of pesticides can be addressed using the existing aquatic risk assessment approach based on fish toxicity data. However, lethal as well as sublethal effects were observed in terrestrial juveniles after dermal exposure to environmentally realistic pesticide concentrations, which cannot be covered using an existing risk assessment approach. Therefore, pesticides should also be evaluated for potential terrestrial toxicity using risk assessment tools before approval. Additionally, effects of co-formulants and adjuvants of pesticides need specific consideration in a future risk assessment as they can increase toxicity of pesticides to aquatic and terrestrial amphibian stages. The chronic duration of combined aquatic and terrestrial exposure was shown to affect amphibian reproduction. Currently, such effects cannot be captured by the existing risk assessment as data involving field scenarios analysing effects of multiple pesticides on amphibian reproduction are too rare to allow comparison to data of other terrestrial vertebrates such as birds and mammals. In the light of these findings, future research should not only address acute and lethal effects, but also chronic and sublethal effects on a population level. As pesticide exposure can adversely affect amphibian populations, their application should be considered even more carefully to avoid further amphibian declines. Overall, this thesis emphasizes the urgent need for a protective pesticide risk assessment for amphibians to preserve and promote stable amphibian populations in agricultural landscapes.
Während es eine Vielzahl von Arbeiten zu der technologischen Entwicklung im Bereich der erneuerbaren Energien gibt, fehlt es jedoch bislang an einer mikroökonomischen Analyse
der Verhaltensmuster der Akteure im Umfeld von Anlagen nach dem EEG. Als Akteure kommen hier in erster Linie der Anlagenbetreiber selbst und der Staat in Betracht.
Im Hinblick auf Anlagenbetrieb und Vergütung der erzeugten Energie können beide mit unterschiedlichsten Interessen und Nutzenkalkülen aufeinander treffen. Diese Arbeit untersucht
mikroökonomische Aspekte des EEG-Förderungssystems. Im Mittelpunkt der Betrachtung stehen die Förderungsmechanismen für Biogasanlagen, die im Hinblick auf mögliche Prinzipal-Agenten-Konflikte einer Untersuchung unterzogen werden.
In dieser Studie sollte hinsichtlich der Entwicklung eines faunistisch begründeten Monitoringkonzeptes für hydrologische Interaktionen untersucht werden, inwieweit die Meiofauna in Hyporheal und Grundwasser in der Lage ist, Oberflächenwasser-Grundwasser-Interaktionen zu reflektieren und die hydrologischen Verhältnisse einer Uferfiltrationsanlage aufzuzeigen. Dafür wurden hydrochemische und faunistische Analysen bezüglich ihrer Aussagekraft miteinander verglichen. Außerdem wurde die Anwendbarkeit des Grundwasser-Fauna-Index (GFI) zur Beurteilung der Stärke des Oberflächenwassereinflusses auf unterirdisches Wasser überprüft. Für die Untersuchung wurde die Uferfiltrationsanlage Flehe der Stadtwerke Düsseldorf ausgewählt, auf deren Gelände 70 vertikale Entnahmebrunnen über eine Strecke von 1,4 km eine Brunnengalerie bilden, die im Jahr insgesamt 11 Mio. m3 Wasser fördert. Am Untersuchungsstandort wurden insgesamt 15 Observationspegel von Februar 2005 bis Januar 2006 faunistisch und hydrochemisch beprobt. Die physikochemische Untersuchung ergab eine Aufteilung des Untersuchungsgebietes in vier Zonen. Neben dem Oberflächenwasser des Rheins [OW Rhein] konnten das Uferfiltrationswasser zwischen Rhein und den Entnahmebrunnen [Hyporheal], alluviales Grundwasser hinter der Brunnengalerie [Alluv. GW] und bei größerer Entfernung zum Rhein landseitiges Grundwasser [landseitiges GW] differenziert werden. Dabei wies der Rhein die typische Charakteristik eines Fließgewässers auf, gekennzeichnet durch eine große Temperaturamplitude mit einem Sommermaximum, hohen Sauerstoffkonzentrationen mit einem Wintermaximum und erhöhten AOX-, DOC- und SAK254nm-Werten. Am Uferfiltrat der Gruppe [Hyporheal] wurde die Wirksamkeit der mikrobiellen Abbauprozesse während der Uferfiltration mit deutlichen Reduzierungen der DOC- und SAK- und Sauerstoffkonzentrationen ersichtlich. Die Gruppe [Alluv. GW] und verstärkt das [landseitige GW] waren durch eine höhere elektrische Leitfähigkeit und erhöhten Bor- und Sulfatkonzentrationen sowie z. T. geringen Sauerstoffgehalten gekennzeichnet. Anhand dieser hydrochemischen Differenzen konnte die unterschiedliche Herkunft des Wassers im Untersuchungsgebiet ermittelt werden Die faunistischen Untersuchungen zeigten ein differenzierteres Bild von den hydrologischen Verhältnissen als die Hydrochemie. Insgesamt konnten fünf ökologische Gruppen ermittelt werden. Die Gruppe [Hyporheal 1] der A-Pegelreihe wies als einzige euryöke Arten auf, die einen stärkeren Oberflächenwassereinfluss anzeigten. Im [Hyporheal 2] der B-Pegelreihe konnte eine artenreiche ökotonale Fauna nachgewiesen werden, während die Proben des alluvialen Grundwassers der C-Pegelreihe [Alluv. GW (Pumpe)] den Einfluss der Entnahmebrunnen reflektierten. In den Pegeln des alluvialen Grundwassers [Alluv. GW] wurde aufgrund der geringeren Beeinflussung der Pumpen artenreichere Zoozönosen vorgefunden. Das [landseitige GW] wies schließlich eine arten- und abundanzarme Fauna auf, die charakteristisch ist für Grundwasser mit geringem Oberflächenwassereinfluss. Folglich konnte die Fauna nicht nur die Herkunft des Grundwassers anzeigen, sondern auch den Einfluss und die Intensität des Oberflächenwassers auf das Grundwasser sowie anthropogene Störungen wie eine verstärkte Kolmation bzw. die Effekte der Wasserentnahme durch die Brunnen. Die Meiofauna im Grundwasserleiter der Uferfiltrationsanlage dürfte somit als Indikator für hydrologische Verhältnisse gut geeignet sein. Der Grundwasser-Fauna-Index konnte als der wichtigste Faktor aller physikochemischen Parameter ermittelt werden, der die faunistischen Gruppen am stärksten beeinflusst. Außerdem war der GFI in der Lage, die Auswirkung und Intensität des Einflusses von Oberflächenwasser auf die einzelnen Probestandorte anzuzeigen. Die hier dargestellten Ergebnisse zeigen, dass die Grundwasserfauna und der GFI viel versprechende Methoden zur Bewertung der hydrologischen Verhältnisse, insbesondere des Einflusses von Oberflächenwasser auf das Grundwasser sind. Daher sind sie als Ergänzung zur hydrochemischen Analyse zu empfehlen und können auch einen wichtigen Beitrag für die Vulnerabilitätsabschätzung leisten.
The research described in this thesis was designed to yield information on the impact of particle-bound pesticides on organisms living in the interface between sediment and water column in a temporarily open estuary (TOCEs). It was hypothesized that natural variables such as salinity and temperature and anthropogenic stressors such as particle-bound pesticides contribute to the variability of the system. A multiple line of evidence approach is necessary due to the variability in sediment type, contaminant distribution and spatial and temporal variability within the ecosystem in particular within TOCEs. The first aim of this thesis was to identify which particle-bound pesticides are important to the contamination of the Lourens River estuary (Western Cape, South Africa), taking into account their environmental concentrations, physico-chemical and toxicological properties (Exposure assessment). The second aim was to identify spatial and temporal variations in particle bound pesticide contamination, natural environmental variables and benthic community structure (effect assessment). The third aim was to test the hypothesis: "does adaptation to fluctuating salinities lead to enhanced survival of the harpacticoid copepod Mesochra parva when exposed to a combination of particle associated chlorpyrifos exposure and hypo-osmotic stress during a 96 h sediment toxicity test?" The last aim was to identify the driving environmental variables (including natural and anthropogenic stressors) in a "natural" (Rooiels River) compared to a "disturbed" (Lourens River) estuary and to identify if and how these variables change the benthic community structure in both estuaries. Data produced in this research thus provide important information to understand the impact of pesticides and its interaction with natural variables in a temporarily open estuary. To summarise, this study indicated, by the use of the multi-evidence approach, that the pesticides endosulfan and chlorpyrifos posed a risk towards benthic organisms in a temporarily open estuary in particular during spring season. Furthermore an important link between pesticide exposure/ toxicity and salinity was identified, which has important implications for the management of temporarily open estuaries.
Organic substances play an essential role for the formation of stable soil structures. In this context, their physico-chemical properties, interactions with mineral soil constituents and soil-water interactions are particu-larly important. However, the underlying mechanisms contributing to soil particle cementation by swollen or-ganic substances (hydrogels) remains unclear. Up to now, no mechanistic model is available which explains the mechanisms of interparticulate hydrogel swelling and its contribution to soil-water interactions and soil structur-al stability. This mainly results from the lack of appropriate testing methods to study hydrogel swelling in soil as well as from the difficulties of adapting available methods to the system soil/hydrogel.
In this thesis, 1H proton nuclear magnetic resonance (NMR) relaxometry was combined with various soil micro- and macrostructural stability testing methods in order to identify the contribution of hydrogel swelling-induced soil-water interactions to the structural stability of water-saturated and unsaturated soils. In the first part, the potentials and limitations of 1H NMR relaxometry to enlighten soil structural stabilization mechanism and vari-ous water populations were investigated. In the second part, 1H-NMR relaxometry was combined with rheologi-cal measurements of soil to assess the contribution of interparticulate hydrogel swelling and various polymer-clay interactions on soil-water interactions and soil structural stability in an isolated manner. Finally, the effects of various organic and mineral soil fractions on soil-water interactions and soil structural stability was assessed in more detail for a natural, agriculturally cultivated soil by soil density fractionation and on the basis of the experiences gained from the previous experiments.
The increased experiment complexity in the course of this thesis enabled to link physico-chemical properties of interparticulate hydrogel structures with soil structural stability on various scales. The established mechanistic model explains the contribution of interparticulate hydrogels to the structural stability of water-saturated and unsaturated soils: While swollen clay particles reduce soil structural stability by acting as lubricant between soil particles, interparticulate hydrogel structures increase soil structural stability by forming a flexible polymeric network which interconnects mineral particles more effectively than soil pore- or capillary water. It was appar-ent that soil structural stability increases with increasing viscosity of the interparticluate hydrogel in dependence on incubation time, soil texture, soil solution composition and external factors in terms of moisture dynamics and agricultural management practices. The stabilizing effect of interparticulate hydrogel structures further in-crease in the presence of clay particles which is attributed to additional polymer-clay interactions and the incor-poration of clay particles into the three-dimensional interparticulate hydrogel network. Furthermore, the simul-taneous swelling of clay particles and hydrogel structures results in the competition for water and thus in a mu-tual restriction of their swelling in the interparticle space. Thus, polymer-clay interactions not only increase the viscosity of the interparticulate hydrogel and thus its ability to stabilize soil structures but further reduce the swelling of clay particles and consequently their negative effects on soil structural stability. The knowledge on these underlying mechanisms enhance the knowledge on the formation of stable soil structures and enable to take appropriate management practices in order to maintain a sustainable soil structure. The additionally out-lined limitations and challenges of the mechanistic model should provide information on areas with optimization and research potential, respectively.
Abstract The present work investigates the wetting characteristics of soils with regard to their dependence on environmental parameters such as water content (WC), pH, drying temperature and wetting temperature of wettable and repellent soils from two contrasting anthropogenic sites, the former sewage disposal field Berlin-Buch and the inner-city park Berlin-Tiergarten. The aim of this thesis is to deepen the understanding of processes and mechanisms leading to changes in soil water repellency. This helps to gain further insight into the behaviour of soil organic matter (SOM) and identifying ways to prevent or reduce the negative effects of soil water repellency (SWR). The first focus of this work is to determine whether chemical reactions are required for wetting repellent samples. This hypothesis was tested by time and temperature dependence of sessile drop spreading on wettable and repellent samples. Additionally, diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy was used to determine whether various drying regimes cause changes in the relative abundance of hydrophobic and hydrophilic functional groups in the outer layer of soil particles and whether these changes can be correlated with water content and the degree of SWR. Finally, by artificially altering the pH in dried samples applying acidic and alkaline reagents in a gaseous state, the influence of only pH on the degree of SWR was investigated separately from the influence of changes in moisture status. The investigation of the two locations Buch and Tiergarten, each exceptionally different in the nature of their respective wetting properties, leads to new insights in the variety of appearance of SWR. The results of temperature, water content and pH dependency of SWR on the two contrasting sites resulted in one respective hypothetical model of nature of repellency for each site which provides an explanation for most of the observations made in this and earlier studies: At the Tiergarten site, wetting characteristics are most likely determined by micelle-like arrangement of amphiphiles which depends on the concentration of water soluble amphiphilic substances, pH and ionic strength in soil solution. At low pH and at high ionic strength, repulsion forces between hydrophilic charged groups are minimized allowing their aggregation with outward orientated hydrophobic molecule moieties. At high pH and low ionic strength, higher repulsion forces between hydrophilic functional groups lead to an aggregation of hydrophobic groups during drying, which results in a layer with outward oriented hydrophilic moieties on soil organic matter surface leading to enhanced wettability. For samples from the Buch site, chemical reactions are necessary for the wetting process. The strong dependence of SWR on water content indicates that hydrolysis-condensation reactions are the controlling mechanisms. Since acid catalyzed hydrolysis is an equilibrium reaction dependent on water content, an excess of water favours hydrolysis leading to an increasing number of hydrophilic functional groups. In contrast, water deficiency favours condensation reactions leading to a reduction of hydrophilic functional groups and thus a reduction of wettability. The results of the present investigation and its comparison with earlier investigations clearly show that SWR is subject to numerous antagonistically and synergistically interacting environmental factors. The degree of influence, which a single factor exerts on SWR, is site-specific, e.g., it is dependent on special characteristics of mineral constituents and SOM which underlies the influence of climate, soil texture, topography, vegetation and the former and current use of the respective site.
Systemic neonicotinoids are one of the most widely used insecticide classes worldwide. In addition to their use in agriculture, they are increasingly applied on forest trees as a protective measure against insect pests. However, senescent leaves containing neonicotinoids might, inter alia during autumn leaf fall, enter nearby streams. There, the hydrophilic neonicotinoids may be remobilized from leaves to water resulting in waterborne exposure of aquatic non-target organisms. Despite the insensitivity of the standard test species Daphnia magna (Crustacea, Cladocera) toward neonicotinoids, a potential risk for aquatic organisms is evident as many other aquatic invertebrates (in particular insects and amphipods) display adverse effects when exposed to neonicotinoids in the ng/L- to low µg/L-range. In addition to waterborne exposure, in particular leaf-shredding invertebrates (= shredders) might be adversely affected by the introduction of neonicotinoid-contaminated leaves into the aquatic environment since they heavily rely on leaf litter as food source. However, dietary neonicotinoid exposure of aquatic shredders has hardly received any attention from researchers and is not considered during aquatic environmental risk assessment. The primary aim of this thesis is, therefore, (1) to characterize foliar neonicotinoid residues and exposure pathways relevant for aquatic shredders, (2) to investigate ecotoxicological effects of waterborne and dietary exposure on two model shredders, namely Gammarus fossarum (Crustacea, Amphipoda) and Chaetopteryx villosa (Insecta, Trichoptera), and (3) to identify biotic and abiotic factors potentially modulating exposure under field conditions.
During the course of this thesis, ecotoxicologically relevant foliar residues of the neonicotinoids imidacloprid, thiacloprid and acetamiprid were quantified in black alder trees treated at field relevant levels. A worst-case model – developed to simulate imidacloprid water concentrations resulting from an input of contaminated leaves into a stream – predicted only low aqueous imidacloprid concentrations (i.e., ng/L-range). However, the model identified dietary uptake as an additional exposure pathway relevant for shredders up to a few days after the leaves’ introduction into the stream. When test organisms were simultaneously exposed (= combined exposure) to neonicotinoids leaching from leaves into the water and via the consumption of contaminated leaves, adverse effects exceeded those observed under waterborne exposure alone. When exposure pathways were separated using a flow-through system, dietary exposure towards thiacloprid-contaminated leaves caused similar sublethal adverse effects in G. fossarum as observed under waterborne exposure. Moreover, the effect sizes observed under combined exposure were largely predictable using the reference model “independent action”, which assumes different molecular target sites to be affected. Dietary toxicity for shredders might, however, be reduced under field conditions since UV-induced photodegradation and leaching decreased imidacloprid residues in leaves and thereby the toxicity for G. fossarum. In contrast, both shredders were found unable to actively avoid dietary exposure. This thesis thus recommends considering dietary exposure towards systemic insecticides, such as neonicotinoids, already during their registration to safeguard aquatic shredders, associated ecosystem functions (e.g., leaf litter breakdown) and ultimately ecosystem integrity.
This thesis was motivated by the need to advance the knowledge on the variability and dynamics of energy fluxes in lakes and reservoirs, as well as about the physical processes that regulate the fluxes at both the air and water side of the air-water interface.
In the first part, I re-examine how mechanical energy, resulting from its major source – the vertical wind energy flux - distributes into the various types of water motions, including turbulent flows and surface and internal waves. Although only a small fraction of the wind energy flux from the atmosphere is transferred to the water, it is crucial for physical, biogeochemical and ecological processes in lentic ecosystems. Based on extensive air- and water-side measurements collected at two small water bodies (< 10 km2), we estimated the energy fluxes and energy content in surface and in internal waves. Overall, the estimated energy fluxes and energy content agree well with results reported for larger water bodies, suggesting that the energetics driving the water motions in enclosed basins is similar, independently of the basin size. Our findings highlight the importance of the surface waves that receive the largest fraction of the wind energy flux, which strongly nonlinearly increases for wind speeds exceeding 3 m s-1. We found that the existing parameterization of the wave height as a function of wind speed and fetch length did not reproduce the measured wave amplitude in lakes. On average, the highest energy content was observed in basin-scale internal waves, together with high-frequency internal waves exhibiting seasonal variability and varies among the aquatic systems. During our analysis, we discovered the diurnal variability of the energy dissipation rates in the studied lake, suggesting biogenic turbulence generation, which appears to be a widespread phenomenon in lakes and reservoirs.
In the second part of the thesis, I addressed current knowledge gaps related to the bulk transfer coefficients (also known as the drag coefficient, the Stanton number and the Dalton number), which are of a particular importance for the bulk estimation of the surface turbulent fluxes of momentum, sensible and latent heat in the atmospheric boundary layer. Their inaccurate representation may lead to significant errors in flux estimates, affecting, for example, the weather and climate predictions or estimations of the near-surface current velocities in lake hydrodynamic models. Although the bulk transfer coefficients have been extensively studied over the past several decades (mainly in marine and large-lake environments), there has been no systematic analysis of measurements obtained at lakes of different size. A significant increase of the transfer coefficients at low wind speeds (< 3 m s-1) has been observed in several studies, but, to date, it has remained unexplained. We evaluated
the bulk transfer coefficients using flux measurements from 31 lakes and reservoirs. The estimates were generally within the range reported in previous studies for large lakes and oceans. All transfer coefficients increased substantially at low wind speeds, which was found to be associated with the presence of gusts and capillary waves (except the Dalton number). We found that the Stanton number is systematically higher than the Dalton number. This challenges the assumption made in the Bowen-ratio method, which is widely used for estimating evaporation rates from micrometeorological measurements. We found that the variability of the transfer coefficients among the lakes could be associated with lake surface area. In flux parameterizations at lake surfaces, it is recommended to consider variations in the drag coefficient and the Stanton number due to wind gustiness and capillary wave roughness while the Dalton number could be considered as constant at all wind speeds.
In the third part of the thesis, I address the key drivers of the near-surface turbulence that control the gas exchange in a large regulated river. As all inland waters, rivers are an important natural source of greenhouse gases. The effects of the widespread alteration and regulation of river flow for human demands on gas exchange is largely unknown. In particular, the near-surface turbulence in regulated rivers has been rarely measured and its drivers have not been identified. While in lakes and reservoirs, near-surface turbulence is mainly related to atmospheric forcing, in shallow rivers and streams it is generated by bottom friction of the gravity-forced flow. The studied large regulated river represents a transition between these two cases. Atmospheric forcing and gravity were the dominant drivers of the near-surface turbulence for a similar fraction of the measurement period. Based on validated scalings, we derived a simple model for estimating the relative contributions of wind and bottom friction to near-surface turbulence in lotic ecosystems with different flow depths. Large diel variability in the near-surface energy dissipation rates due to flow regulation leads to the same variability in gas exchange. This suggests that estimates of gas fluxes from rivers are biased by measurements performed predominantly during daytime.
In addition, the novelty in all the analyses described above is the use of the turbulent surface fluxes measured directly by the eddy-covariance technique – at the moment of writing, the most advanced method. Overall, this thesis is of a potential interest for a broad range of scientific disciplines, including limnology, micrometeorology and open channel hydraulics.
The largest population of the anadromous Allis shad (A. alosa) of the 19th century was found in River Rhine and has to be considered extinct today. To facilitate the return of A. alosa into River Rhine an EU LIFE-project was initiated in 2007. The overall objective of this thesis was to assist aquaculture and stocking-measures at River Rhine, as well as to support restoration and conservation of populations of Allis shad in Europe.
By culturing the free-swimming nematode T. aceti in a solution of cider vinegar we developed a cost-effective live food organism for the larviculture of fish. As indicated by experiments with C. maraena, T. aceti cannot be regarded as an alternative to Artemia nauplii. However it has to be considered a suitable supplemental feed in the early rearing of C. maraena by providing essential fatty acids, thereby optimizing growth.
Also mass-marking practices with Oxytetracycline, as they are applied in the restocking of Allis shad have been evaluated. In experiments with D. rerio we demonstrated that water hardness can detrimentally affect mortality during marking and has to be considered crucial in the development of marking protocols for freshwater fish.
In order to get independent from wild spawners an ex-situ Broodstock-facility for Allis shad was established in 2011. Upon examination of two complete year classes of this broodstock, we found a high prevalence of various malformations, which could be traced back to distinct cysts developing one month post hatch. Despite applying a variety of clinical tests we could not identify any infectious agents causing these malformations. The observed malformations are probably a consequence of suboptimal feeding practices or the properties of the physio-chemical rearing environment.
The decline of stocks of A. alosa in Europe has been largely explained with the increase of river temperatures as a consequence of global warming. By investigating the temperature physiology of larval Allis shad we demonstrated that A. alosa ranges among the most thermo-tolerant species in Europe and that correlations between rising temperatures and the disappearance of this species have to be understood in a synecological context and by integrating a variety of stressors other than temperature. By capturing and examining juvenile and adult Allis shad from River Rhine, we demonstrated the first natural reproduction of A. alosa in River Rhine since nearly 100 years and the success of stocking measures within the framework of the LIFE project.
In the last decades, it became evident that the world is facing an unprecedented, human-induced global biodiversity crisis with amphibians being one of the most threatened species groups. About 41% of the amphibian species are classified as endangered by the IUCN, but even in amphibian species that are listed as "least concern", population declines can be observed on a local level. With land-use change and agrochemicals (i.e. pesticides), two of the main drivers for this amphibian decline are directly linked to intensive agriculture, which is the dominant landscape type in large parts of Europe. Thus, understanding the situation of amphibians in the agricultural landscape is crucial for conservation measures. In the present thesis, I investigated the effects of viticulture on amphibian populations around Landau in der Pfalz (Germany) in terms of habitat use, pesticide exposure, biometric traits as well as genetic and age structure. From the perspective of amphibians, land-use change means usually the destruction of habitats in agricultural landscapes, which often leads to landscape fragmentation. Thus, I followed the question if also vineyards lead to the fragmentation of the landscape and if pesticides that are frequently used in viticulture have to be considered as a factor too, so if there is a chemical landscape fragmentation. Using telemetry, I could show that common toads (Bufo bufo) can be found directly in vineyards, but that they tend to avoid them as habitat. Analysing the genetic structure of common frogs (Rana temporaria) revealed that vineyards have to be considered as a barrier for amphibians. To identify if pesticides contribute to the resulting landscape fragmentation, I conducted an arena choice experiment in the laboratory in which I found evidence for an avoidance of pesticide-contaminated soil. Such an avoidance could be one of the underlying reasons for a potential chemical landscape fragmentation. By combining telemetry data with information about pesticide applications from local wine growers, I could show that a large part of the common toads is likely to come in contact with pesticides. Further, I demonstrated that the agricultural landscape, probably due to the application of pesticides, can have negative effects on the reproduction capacity of common toads. By studying palmate newts (Lissotriton helveticus) I found that adult newts from agricultural ponds are smaller than those from forest ponds. As I did not find differences in the age structure and growth, these differences might be carry-over effects from earlier life stages. While agricultural ponds might be suitable habitats for adult palmate newts, the potential carry-over effect indicates suboptimal conditions for larvae and/or juveniles. I conclude that the best management measure for sustaining amphibians in the agricultural landscape would be a heterogeneous cultural landscape with a mosaic of different habitat patches that work without or at least a reduced amount of pesticides. Green corridors between populations and different habitats would allow migrating individuals to avoid agricultural and thus pesticide-contaminated areas. This would reduce the pesticide exposure risk of amphibians, while preventing the fragmentation of the landscape and thus the isolation of populations.