Boltersdorf S, Werner W. Regional variation in the nitrogen content and δ15N signatures of lichen... more Boltersdorf S, Werner W. Regional variation in the nitrogen content and δ15N signatures of lichens in relation to atmospheric nitrogen deposition. Presented at the 24ndTask Force Meeting - UNECE ICP Vegetation, Rapperswil-Jona (Switzerland)
Boltersdorf S, Pesch R, Schröder W, Werner W. Physiological responses: Do lichens, mosses and tre... more Boltersdorf S, Pesch R, Schröder W, Werner W. Physiological responses: Do lichens, mosses and tree bark react with different carbon and nitrogen isotope patterns along a nitrogen deposition gradient? Presented at the 27th Task Force Meeting – UNECE ICP Vegetation, Paris (France)
Boltersdorf S, Schultze J, Werner W. Comparison of nitrogen content and δ15N-signatures in mosses... more Boltersdorf S, Schultze J, Werner W. Comparison of nitrogen content and δ15N-signatures in mosses (*Hypnum cupressiforme*) and lichens (*Parmelia sulcata*) with nitrogen deposition rates of Germany. Presented at the 23rd Task Force Meeting - UNECE ICP Vegetation, Brussels (Belgium)
Abstract During the last decade a variety of perennial bioenergy crops (PECs) have been introduce... more Abstract During the last decade a variety of perennial bioenergy crops (PECs) have been introduced into European agriculture. This study was designed to investigate the impact of various PECs on earthworm community patterns (species composition, numbers, biomass, α-diversity, life-form categories) at a landscape scale in Western Germany. The PECs investigated were cup plant (CP), tall wheatgrass (TW) and giant knotweed (GK). In total, 4 field replicates of each perennial crop were investigated at 9 study sites with the exception of CP, for which only 3 replicate sites were available. PECs were compared with silage maize as an annual bioenergy crop (AEC) and permanent grasslands (PGL). The earthworm community of the study area consisted of 13 species in total. Mean species number ranged from 2.7 (AEC)
2015 7th Workshop on Hyperspectral Image and Signal Processing: Evolution in Remote Sensing (WHISPERS), 2015
During summer 2014 a water treatment experiment was adopted on potatoes plants (Solanum tuberosum... more During summer 2014 a water treatment experiment was adopted on potatoes plants (Solanum tuberosum L. Cilena, n=60) with the objective to detect plant water stress. Therefore, three different sensors were applied, a hyperspectral and broadband thermal infrared (TIR) camera to measure canopy temperature, as well as a leaf porometer to measure stomatal conductance. The results of this study show that water stress can be detected from 2 days after stress based on stomatal conductance measurements using a descriptive t-test (p=0.044∗ at 5% level of significance). Applying the prominent crop water stress index (CWSI) based on canopy, dry and wet references temperatures, control and treatment can be significantly separated starting 8 days after stress (p<0.001∗∗∗) using both hyperspectral and broadband data. Thus, our hypothesis of an earlier and more accurate water stress detection using a hyperspectral TIR system must be falsified for this study.
2014 6th Workshop on Hyperspectral Image and Signal Processing: Evolution in Remote Sensing (WHISPERS), 2014
A plant species discrimination experiment was carried out using emissive thermal infrared imaging... more A plant species discrimination experiment was carried out using emissive thermal infrared imaging spectroscopy. This was a first application of the Telops HyperCam-LW for vegetation analysis. The Telops HyperCam-LW is a Fourier-transform imaging spectrometer designed for airborne, field and laboratory application. Compared to laboratory spectrometers, this spectrometer allows fast measurements at high spectral resolution in the 8–12 μm spectral range. This paper shows that this spectrometer — in a field measurement setup — is capable of capturing high quality spectral information, comparable to laboratory instruments. We used this spectrometer to capture leaf spectra, generally considered as spectrally flat surfaces. Using the Telops HyperCam-LW, it was possible to capture the subtle signatures and perform species discrimination analysis with very good results. Further, the potential of a hyperspectral airborne or spaceborne study focusing on vegetation analysis is discussed.
Werner W, Schultze J, Boltersdorf S. Patterns of wet deposition types and element concentration i... more Werner W, Schultze J, Boltersdorf S. Patterns of wet deposition types and element concentration in mosses in Germany. Presented at the 24th Task Force Meeting - UNECE ICP Vegetation, Raperswil-Jona (Switzerland)
Boltersdorf S, Werner W. Regional variation in the nitrogen content and δ15N signatures of lichen... more Boltersdorf S, Werner W. Regional variation in the nitrogen content and δ15N signatures of lichens in relation to atmospheric nitrogen deposition. Presented at the 24ndTask Force Meeting - UNECE ICP Vegetation, Rapperswil-Jona (Switzerland)
Flächenbezogene Artenzahlen sind besonders im Kontext von Monitoringprojekten grundlegend für die... more Flächenbezogene Artenzahlen sind besonders im Kontext von Monitoringprojekten grundlegend für die Beurteilung von Veränderungen der Biodiversität. Diese Studie vergleicht die von neun Bearbeitern (5 Einzelbearbeiter, 2 Zweierteams) erfasste Zahl an Gefäßpflanzenarten bei Vegetationserhebungen auf markierten Flächen von 4, 100 und 400 m2 Größe in einem artenreichen Kalkbuchenwald im Göttinger Stadtwald. Dabei wurden Bearbeiter- und Zeiteffekte untersucht, sowie artspezifische Übersehensraten, Fehlbestimmungsraten und Ungenauigkeiten bei der Zuordnung von Pflanzenindividuen zur jeweiligen Aufnahmefläche (Fehlzuordnungsraten) abgeschätzt. Protokollierte Fragen ließen keine systematischen Unterschiede bei der Vertrautheit der Bearbeiter mit der Vegetation vor Ort erkennen, so dass Ausbildung und Erfahrung für gefundene Unterschiede ausschlaggebend sein dürften. Bei den 4 m2 großen Erhebungseinheiten ergaben sich bei der Artenzahl relative Abweichungen der Bearbeiter vom Erwartungswert v...
Studying the effect of surface ozone (O3) and water stress on tree growth is important for planni... more Studying the effect of surface ozone (O3) and water stress on tree growth is important for planning sustainable forest management and forest ecology. In the present study, a 22-year long time series (1998–2019) on basal area increment (BAI) and fructification severity of European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) H.Karst.) at five forest sites in Western Germany (Rhineland Palatinate) was investigated to evaluate how it correlates with drought and stomatal O3 fluxes (PODY) with an hourly threshold of uptake (Y) to represent the detoxification capacity of trees (POD1, with Y = 1 nmol O3 m−2 s−1). Between 1998 and 2019, POD1 declined over time by on average 0.31 mmol m−2 year−1. The BAI showed no significant trend at all sites, except in Leisel where a slight decline was observed over time (−0.37 cm2 per year, p < 0.05). A random forest analysis showed that the soil water content and daytime O3 mean concentration were the best predictors of BAI at all s...
Boltersdorf S, Werner W. Lichen nitrogen and carbon isotopic composition as indication for atmosp... more Boltersdorf S, Werner W. Lichen nitrogen and carbon isotopic composition as indication for atmospheric nitrogen pollution - a synopsis. Presented at the Joint European Stable Isotope Users group Meeting (JESIUM), Ghent (Belgium)
Werner W, Boltersdorf S. Nitrogen concentrations and δ15N-ratios in epiphytic lichen *Xanthoria p... more Werner W, Boltersdorf S. Nitrogen concentrations and δ15N-ratios in epiphytic lichen *Xanthoria parietina* in correlation to nitrogen depositions rates and δ15N-ratios of colonized tree bark. Presented at the 22nd Task Force Meeting - UNECE ICP Vegetation, Brunswick (Germany)
Boltersdorf S, Werner W. Characterisation of nitrogen deposition and source attribution by using ... more Boltersdorf S, Werner W. Characterisation of nitrogen deposition and source attribution by using N-concentrations and δ15N-signatures of epiphytic lichens (*Xanthoria parietina* and *Hypogymnia physodes*) in Germany. Presented at the 40th annual conference of the Ecological Society of Germany, Switzerland and Austria (GFOe), Giessen (Germany)
Boltersdorf S, Werner W. Trends in N quantity and δ15N signatures of different N deposition types... more Boltersdorf S, Werner W. Trends in N quantity and δ15N signatures of different N deposition types in Germany indicated by lichens and bark samples. Presented at the 25th Task Force Meeting - UNECE ICP Vegetation, Brescia (Italy)
ABSTRACT: This study evaluated the influence of lime (dolomite) and damage class on Norway spruce... more ABSTRACT: This study evaluated the influence of lime (dolomite) and damage class on Norway spruce (Picea abies) photosynthetic pigmentation (chlorophylls), needle water content and needle reflectance. As expected, total chlorophyll content (Chla+ b) increased ...
Boltersdorf S, Werner W. Regional variation in the nitrogen content and δ15N signatures of lichen... more Boltersdorf S, Werner W. Regional variation in the nitrogen content and δ15N signatures of lichens in relation to atmospheric nitrogen deposition. Presented at the 24ndTask Force Meeting - UNECE ICP Vegetation, Rapperswil-Jona (Switzerland)
Boltersdorf S, Pesch R, Schröder W, Werner W. Physiological responses: Do lichens, mosses and tre... more Boltersdorf S, Pesch R, Schröder W, Werner W. Physiological responses: Do lichens, mosses and tree bark react with different carbon and nitrogen isotope patterns along a nitrogen deposition gradient? Presented at the 27th Task Force Meeting – UNECE ICP Vegetation, Paris (France)
Boltersdorf S, Schultze J, Werner W. Comparison of nitrogen content and δ15N-signatures in mosses... more Boltersdorf S, Schultze J, Werner W. Comparison of nitrogen content and δ15N-signatures in mosses (*Hypnum cupressiforme*) and lichens (*Parmelia sulcata*) with nitrogen deposition rates of Germany. Presented at the 23rd Task Force Meeting - UNECE ICP Vegetation, Brussels (Belgium)
Abstract During the last decade a variety of perennial bioenergy crops (PECs) have been introduce... more Abstract During the last decade a variety of perennial bioenergy crops (PECs) have been introduced into European agriculture. This study was designed to investigate the impact of various PECs on earthworm community patterns (species composition, numbers, biomass, α-diversity, life-form categories) at a landscape scale in Western Germany. The PECs investigated were cup plant (CP), tall wheatgrass (TW) and giant knotweed (GK). In total, 4 field replicates of each perennial crop were investigated at 9 study sites with the exception of CP, for which only 3 replicate sites were available. PECs were compared with silage maize as an annual bioenergy crop (AEC) and permanent grasslands (PGL). The earthworm community of the study area consisted of 13 species in total. Mean species number ranged from 2.7 (AEC)
2015 7th Workshop on Hyperspectral Image and Signal Processing: Evolution in Remote Sensing (WHISPERS), 2015
During summer 2014 a water treatment experiment was adopted on potatoes plants (Solanum tuberosum... more During summer 2014 a water treatment experiment was adopted on potatoes plants (Solanum tuberosum L. Cilena, n=60) with the objective to detect plant water stress. Therefore, three different sensors were applied, a hyperspectral and broadband thermal infrared (TIR) camera to measure canopy temperature, as well as a leaf porometer to measure stomatal conductance. The results of this study show that water stress can be detected from 2 days after stress based on stomatal conductance measurements using a descriptive t-test (p=0.044∗ at 5% level of significance). Applying the prominent crop water stress index (CWSI) based on canopy, dry and wet references temperatures, control and treatment can be significantly separated starting 8 days after stress (p<0.001∗∗∗) using both hyperspectral and broadband data. Thus, our hypothesis of an earlier and more accurate water stress detection using a hyperspectral TIR system must be falsified for this study.
2014 6th Workshop on Hyperspectral Image and Signal Processing: Evolution in Remote Sensing (WHISPERS), 2014
A plant species discrimination experiment was carried out using emissive thermal infrared imaging... more A plant species discrimination experiment was carried out using emissive thermal infrared imaging spectroscopy. This was a first application of the Telops HyperCam-LW for vegetation analysis. The Telops HyperCam-LW is a Fourier-transform imaging spectrometer designed for airborne, field and laboratory application. Compared to laboratory spectrometers, this spectrometer allows fast measurements at high spectral resolution in the 8–12 μm spectral range. This paper shows that this spectrometer — in a field measurement setup — is capable of capturing high quality spectral information, comparable to laboratory instruments. We used this spectrometer to capture leaf spectra, generally considered as spectrally flat surfaces. Using the Telops HyperCam-LW, it was possible to capture the subtle signatures and perform species discrimination analysis with very good results. Further, the potential of a hyperspectral airborne or spaceborne study focusing on vegetation analysis is discussed.
Werner W, Schultze J, Boltersdorf S. Patterns of wet deposition types and element concentration i... more Werner W, Schultze J, Boltersdorf S. Patterns of wet deposition types and element concentration in mosses in Germany. Presented at the 24th Task Force Meeting - UNECE ICP Vegetation, Raperswil-Jona (Switzerland)
Boltersdorf S, Werner W. Regional variation in the nitrogen content and δ15N signatures of lichen... more Boltersdorf S, Werner W. Regional variation in the nitrogen content and δ15N signatures of lichens in relation to atmospheric nitrogen deposition. Presented at the 24ndTask Force Meeting - UNECE ICP Vegetation, Rapperswil-Jona (Switzerland)
Flächenbezogene Artenzahlen sind besonders im Kontext von Monitoringprojekten grundlegend für die... more Flächenbezogene Artenzahlen sind besonders im Kontext von Monitoringprojekten grundlegend für die Beurteilung von Veränderungen der Biodiversität. Diese Studie vergleicht die von neun Bearbeitern (5 Einzelbearbeiter, 2 Zweierteams) erfasste Zahl an Gefäßpflanzenarten bei Vegetationserhebungen auf markierten Flächen von 4, 100 und 400 m2 Größe in einem artenreichen Kalkbuchenwald im Göttinger Stadtwald. Dabei wurden Bearbeiter- und Zeiteffekte untersucht, sowie artspezifische Übersehensraten, Fehlbestimmungsraten und Ungenauigkeiten bei der Zuordnung von Pflanzenindividuen zur jeweiligen Aufnahmefläche (Fehlzuordnungsraten) abgeschätzt. Protokollierte Fragen ließen keine systematischen Unterschiede bei der Vertrautheit der Bearbeiter mit der Vegetation vor Ort erkennen, so dass Ausbildung und Erfahrung für gefundene Unterschiede ausschlaggebend sein dürften. Bei den 4 m2 großen Erhebungseinheiten ergaben sich bei der Artenzahl relative Abweichungen der Bearbeiter vom Erwartungswert v...
Studying the effect of surface ozone (O3) and water stress on tree growth is important for planni... more Studying the effect of surface ozone (O3) and water stress on tree growth is important for planning sustainable forest management and forest ecology. In the present study, a 22-year long time series (1998–2019) on basal area increment (BAI) and fructification severity of European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) H.Karst.) at five forest sites in Western Germany (Rhineland Palatinate) was investigated to evaluate how it correlates with drought and stomatal O3 fluxes (PODY) with an hourly threshold of uptake (Y) to represent the detoxification capacity of trees (POD1, with Y = 1 nmol O3 m−2 s−1). Between 1998 and 2019, POD1 declined over time by on average 0.31 mmol m−2 year−1. The BAI showed no significant trend at all sites, except in Leisel where a slight decline was observed over time (−0.37 cm2 per year, p < 0.05). A random forest analysis showed that the soil water content and daytime O3 mean concentration were the best predictors of BAI at all s...
Boltersdorf S, Werner W. Lichen nitrogen and carbon isotopic composition as indication for atmosp... more Boltersdorf S, Werner W. Lichen nitrogen and carbon isotopic composition as indication for atmospheric nitrogen pollution - a synopsis. Presented at the Joint European Stable Isotope Users group Meeting (JESIUM), Ghent (Belgium)
Werner W, Boltersdorf S. Nitrogen concentrations and δ15N-ratios in epiphytic lichen *Xanthoria p... more Werner W, Boltersdorf S. Nitrogen concentrations and δ15N-ratios in epiphytic lichen *Xanthoria parietina* in correlation to nitrogen depositions rates and δ15N-ratios of colonized tree bark. Presented at the 22nd Task Force Meeting - UNECE ICP Vegetation, Brunswick (Germany)
Boltersdorf S, Werner W. Characterisation of nitrogen deposition and source attribution by using ... more Boltersdorf S, Werner W. Characterisation of nitrogen deposition and source attribution by using N-concentrations and δ15N-signatures of epiphytic lichens (*Xanthoria parietina* and *Hypogymnia physodes*) in Germany. Presented at the 40th annual conference of the Ecological Society of Germany, Switzerland and Austria (GFOe), Giessen (Germany)
Boltersdorf S, Werner W. Trends in N quantity and δ15N signatures of different N deposition types... more Boltersdorf S, Werner W. Trends in N quantity and δ15N signatures of different N deposition types in Germany indicated by lichens and bark samples. Presented at the 25th Task Force Meeting - UNECE ICP Vegetation, Brescia (Italy)
ABSTRACT: This study evaluated the influence of lime (dolomite) and damage class on Norway spruce... more ABSTRACT: This study evaluated the influence of lime (dolomite) and damage class on Norway spruce (Picea abies) photosynthetic pigmentation (chlorophylls), needle water content and needle reflectance. As expected, total chlorophyll content (Chla+ b) increased ...
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