Spectral fingerprinting: characterizing suspended sediment sources by the use of VNIR-SWIR spectral information

Purpose

Knowledge of sediment sources is a prerequisite for sustainable management practices and may furthermore improve our understanding of water and sediment fluxes. Investigations have shown that a number of characteristic soil properties can be used as “fingerprints” to trace back the sources of river sediments. Spectral properties have recently been successfully used as such characteristics in fingerprinting studies. Despite being less labour-intensive than geochemical analyses, for example, spectroscopy allows measurements of small amounts of sediment material (>60 mg), thus enabling inexpensive analyses even of intra-event variability. The focus of this study is on the examination of spectral properties of fluvial sediment samples to detect changes in source contributions, both between and within individual flood events.

Materials and methods

Sediment samples from the following three different origins were collected in the Isábena catchment (445 km²) in the central Spanish Pyrenees: (1) soil samples from the main potential source areas, (2) stored fine sediment from the channel bed once each season in 2011 and (3) suspended sediment samples during four flood events in autumn 2011 and spring 2012 at the catchment outlet as well as at several subcatchment outlets. All samples were dried and measured for spectral properties in the laboratory using an ASD spectroradiometer. Colour parameters and physically based features (e.g. organic carbon, iron oxide and clay content) were calculated from the spectra. Principal component analyses (PCA) were applied to all three types of samples to determine natural clustering of samples, and a mixing model was applied to determine source contributions.

Results and discussion

We found that fine sediment stored in the river bed seems to be mainly influenced by grain size and seasonal variability, while sampling location—and thus the effect of individual tributaries or subcatchments—seem to be of minor importance. Suspended sediment sources were found to vary between, as well as within, flood events; although badlands were always the major source. Forests and grasslands contributed little (<10 %), and other sources (not further determinable) contributed up to 40 %. The analyses further suggested that sediment sources differ among the subcatchments and that subcatchments comprising relatively large proportions of badlands contributed most to the four flood events analyzed.

Conclusions

Spectral fingerprints provide a rapid and cost-efficient alternative to conventional fingerprint properties. However, a combination of spectral and conventional fingerprint properties could potentially permit discrimination of a larger number of source types.     

New sources of resistance to Colletotrichum truncatum race Ct0 and Ct1 in Lens culinaris Medikus subsp. culinaris obtained by single plant selection in germplasm accessions

Anthracnose caused by the fungal pathogen Colletotrichum truncatum is a severe disease of lentil (Lens culinaris Medikus subsp. culinaris) causing premature defoliation and deep penetrating lesions on the stems leading to wilting and plant death. A total of 579 accessions from 20 countries were obtained from four germplasm collections in Russia, Poland, Bulgaria and Hungary. The accessions were collected between 1923 and 1988 and comprised mostly landraces. Consequently, many of the resistant entries contained susceptible plants which necessitated one or two cycles of selection of individual resistant plants for selfing and re-testing with the pathogen. Under controlled environmental conditions, plants of each accession were inoculated at early flower with C. truncatum race Ct0 (isolate 95A8) and race Ct1 (isolate 95B36), separately. Scoring of symptoms included number of lesions on the main stem, lesion penetration into the stem and amount of wilting. Resistance was obtained by single plant selection in 23 lentil accessions (4.0 %). Fifteen lines were generated with resistance to race Ct1 (2.6 %), seven with resistance to race Ct0 (1.2 %), and one line with resistance to both races. This is the first report on resistance in L. culinaris to C. truncatum race Ct0 as well as to the two races combined. Seed of homozygous resistant lines can be requested from the corresponding author, and are labeled with their original accession number with the prefix either -Ct0, -Ct1 or -Ct0Ct1 indicating resistance to one or both races of C. truncatum.     

An alternative method to estimate zero flow temperature differences for Granier's thermal dissipation technique

Calibration of the Granier thermal dissipation technique for measuring stem sap flow in trees requires determination of the temperature difference (DeltaT) between a heated and an unheated probe when sap flow is zero (DeltaT(max)). Classically, DeltaT(max) has been estimated from the maximum predawn DeltaT, assuming that sap flow is negligible at nighttime. However, because sap flow may continue during the night, the maximum predawn DeltaT value may underestimate the true DeltaT(max). No alternative method has yet been proposed to estimate DeltaT(max) when sap flow is non-zero at night. A sensitivity analysis is presented showing that errors in DeltaT(max) may amplify through sap flux density computations in Granier's approach, such that small amounts of undetected nighttime sap flow may lead to large diurnal sap flux density errors, hence the need for a correct estimate of DeltaT(max). By rearranging Granier's original formula, an optimization method to compute DeltaT(max) from simultaneous measurements of diurnal DeltaT and micrometeorological variables, without assuming that sap flow is negligible at night, is presented. Some illustrative examples are shown for sap flow measurements carried out on individuals of Erica arborea L., which has needle-like leaves, and Myrica faya Ait., a broadleaf species. We show that, although DeltaT(max) values obtained by the proposed method may be similar in some instances to the DeltaT(max) predicted at night, in general the values differ. The procedure presented has the potential of being applied not only to Granier's method, but to other heat-based sap flow systems that require a zero flow calibration, such as the Cermák et al. (1973) heat balance method and the T-max heat pulse system of Green et al. (2003).     

Concentrations of minerals in the canine prostatic fluid

Current knowledge about the composition of the prostate fluid in healthy male dogs is limited and restricted to small case numbers. Furthermore, published data often vary significantly regarding sample processing and analytical methods. Therefore, we aimed to provide data on the composition of electrolytes and minerals in the canine prostatic fluid in a larger population (n = 30 dogs/samples) and to compare these results with the existing literature. Concentrations of sodium, potassium and copper analysed in our population were most consistent with those in the literature. Different to this, concentrations of total calcium, magnesium, zinc and inorganic phosphate varied. Whereas magnesium, zinc and inorganic phosphate seemed to depend on the analysis method, total calcium concentrations differed if centrifugation was performed or not. Our results clearly indicate a need for standardization of methods for analysis of seminal plasma components.     

Einfluss unterschiedlicher grundwasserstandsverla¨ufe auf botanische zusammensetzung,wasserverbrauch und ertrag auf reliefiertem niedermoor bei differenzierter bewirtschaftung

Die Ausformung der Grünlandvegetation wird in entscheidendem Maße von den Grundwasserständen bestimmt. Die Nutzung spielt aber eine außerordentlich große Rolle bei entsprechenden Modifikationen. Ebenso ist wesentlich, welche Arten im Ausgangsbestand etabliert sind oder im Bodensamenvorrat bzw. als Diasporen vorkommen. Der Gesamtwasserverbrauch von Pflanzenbeständen wird durch komplizierte Wechselwirkungen zwischen Artenzusammensetzung und Nutzungsweise bestimmt. Mähbestände mit zweimaliger Nutzung benötigten in allen Versuchsjahren eindeutig mehr Wasser als Weidebestände, die viermal abgeweidet wurden. Im Ertrag gab es nur geringe Unterschiede zu Gunsten der Mähnutzung. Aus qualitativer Sicht ist das physiologisch jüngere Weidefutter überlegen. Im speziellen Wasserverbrauch bestätigte sich die Weide als wassersparende Variante der Niedermoorbewirtschaftung. Hochwüchsige und massereiche Mähbestände benötigen sehr viel Wasser, das in nordostdeutschen Niedermooren nur über Fremdwasserzufuhr bereitgestellt werden kann. Auch aus der Sicht des Bodenschutzes (Verdichtung, besserer kapillarer Wasseraufstieg, Reduktion der NO 3 -Freisetzung usw.) sollte die Weide die bestimmende Form der extensiven Grünlandnutzung sein.     

Kennzeichnung von eigenschaften der folgeböden nordostdeutscher niedermoore

Aufgrund intensiver landwirtschaftlicher Nutzung unterliegen Niedermoore gravierenden Struktur‐ und Funktionsveränderungen. Mineralisierung führt zur Abnahme des Gehaltes an organischer Bodensubstanz bis zum vollständigen Verzehr des Torfkörpers und damit zur Entstehung von Folgeböden. Dabei erlangen die unterschiedlichen Untergrundsubstrate, Mudden und mineralische Substrate unterschiedlicher Korngrößenzusammensetzung, immer größeren Einfluß auf die Ausprägung der neu entstehenden Bodentypen. Aus Mudden hervorgehende organische Folgeböden sind teilweise als vollkommen neue Bodensubstrate anzusehen, deren Eigenschaften wenig erforscht sind. Für die aus mineralisch unterlagerten Mooren entstehenden Folgeböden ist die Entwicklung zu Anmooren und Humussanden bekannt, jedoch noch nicht näher untersucht. Es werden erste Ergebnisse von Untersuchungen zu Bodenkennwerten dieser Böden vorgestellt. Mit welcher Entstehung von Bodentypen zu rechnen ist und welche Faktoren in diesem Prozeß von Bedeutung sind, wird abgeleitet. Mögliche Nutzungsperspektiven, die sich in Nutzungs‐ und Entwicklungskonzepte für Niedermoore eingliedern, werden aufgezeigt.     

Assessing natural hazards in forestry for risk management: a review

We address the problem of how to integrate risk assessment into forest management and therefore provide a comprehensive review of recent and past literature on risk analysis and modeling and, moreover, an evaluation and summary on these papers. We provide a general scheme on how to integrate concepts of risk into forest management decisions. After an overview of the risk management process and the main hazards in forests (storm, snow, insects, fire), the paper focuses on the principal methods used to assess risks from these hazards for commercial forestry. We review mechanistic models, empirical models, and expert systems and consider the needs for different spatial scales of risk assessment, from the regional to the single-tree level. In addition to natural hazards and their secondary effects, we deal with economic aspects of risk analysis. Monte Carlo simulations to deal with volatile timber prices and ways to include risk in classical Faustmann approaches are briefly discussed along with the integration of portfolio theory into forest management decision making and attitude toward risk. Special attention is paid to the implications for risk modeling under climate change.     

Drei Jahre Vogelschutzstatistik im saarländischen Staats- und Gemeindewald

Summary View of bird protection measures in Saarland Bird protection measures are carried out in the public and communal forests of Saarland since many years. From 1971 to 1973 the results of controlling the nest boxes in autumn were evaluated centrally. 12.6% of the boxes were damaged or stolen, 16.9% were unoccupied and 65,1% hatched. The rest were boxes containing died eggs or broods as well as wasps and other inquilines.Titmice were the most frequent breeding birds (68,1%), followed byMuscicapa spec. (14.1%) andSitta europaea (6.7%). This shows that nest boxes are for the benefit of common birds only. They don't show an advancement of rare species. Therefore a reorientation is planned with regard to the advancement of more rare bird species.     

Regeneration niches of Norway spruce (<Emphasis Type="Italic">Picea abies</Emphasis> [L.] Karst.) saplings in small canopy gaps in mixed mountain forests of the Bavarian Limestone Alps

Natural regeneration measurements are the main silvicultural objective in overaged protective forests of the Bavarian Limestone Alps. While manifold problems with these stands, especially the impact of browsing, are widely recognised, the regeneration niches of Norway spruce (Picea abies [L.] Karst.) are insufficiently known. The purpose of this study was to determine favourable combinations of site factors for the development of spruce in small, unfenced canopy gaps, located on Aposerido-Fagetum caricetosum albae forest sites. We recorded the occurrence of spruce saplings (as dependent variable) and of six site factors (as independent variables) on 480 0.5 m²-subplots. In addition, we estimated the coverage of six acid adapted plant species to determine correlations with the humus depth. A binary logistic regression analysis was used to predict the probability of the occurrence of a spruce sapling in dependency of the different site factors. Supported by other studies, we assumed that the supply of solar radiation was adequate for the sufficient regeneration of spruce within the canopy gaps. Other site factors significantly determined the regeneration niches of spruce saplings. More spruce saplings were found near hindrances and on rough surfaces than would be expected from a random occurrence of saplings. These microsite types may have characteristics, especially protection against snow gliding that promotes spruce establishment. A calculated “hindrance index”, which accounted for the number, and the distance of surrounding hindrances might be a good specific value to describe the influence of hindrances on steep slopes. The sapling establishment decreased on thin humus layers. Our assumption for the sites was that thick organic layers might represent a good seedbed for spruce. Decayed dead wood was scarce, but was exceedingly favoured by spruce saplings. Results obtained suggest that the natural regeneration establishment of spruce on steep slopes can be successfully influenced by site factors which inhibit the influence of snow gliding. According to a “positive microsite” concept, we recommend for artificial regeneration measurements with spruce, microsites close to hindrances (e.g. stumps, downed trees) and Vaccinium myrtillus as a predictor for thick, acid humus layers.     

Common Kibra alleles are associated with human memory performance

Human memory is a polygenic trait. We performed a genome-wide screen to identify memory-related gene variants. A genomic locus encoding the brain protein KIBRA was significantly associated with memory performance in three independent, cognitively normal cohorts from Switzerland and the United States. Gene expression studies showed that KIBRA was expressed in memory-related brain structures. Functional magnetic resonance imaging detected KIBRA allele-dependent differences in hippocampal activations during memory retrieval. Evidence from these experiments suggests a role for KIBRA in human memory.