Data assimilation in forest inventories at stand level

Data assimilation (DA) is a potentially interesting method for forestry if new stand level data about forest attributes are made available at short time intervals. DA is a method where an estimate is forecasted by a model and updated when a new measurement is made. A weighted average of the forecast and the measurement is obtained as the new current state, which increases the accuracy of the estimate. In areas like meteorology DA has been successfully applied for a long time. In this case the availability of very frequent satellite data makes it possible to update weather forecasts several times a day and obtain accurate forecasts. Forest inventories in the traditional way, by field campaigns, are expensive and thus provide new data only every 10-20 years. During this long time a lot of changes due to growth, management and disturbances might occur in the forest stands of interest. Thus, old data are discarded when new data are obtained from a new campaign, and the forecasts of the current state are only based on the last measurement. Since many types of remotely sensed data, e.g. from laser scanners, optical satellite sensors, and radars, have become available during recent years, there are now good opportunities to apply DA also in the context of forest inventory. In this thesis I focus on stand level forest inventories. A first theoretical study with simulated data showed that DA has a strong potential to be successfully applied in forestry and increase the accuracy of inventory estimates. However, the second study, the first with empirical data, pointed at problems to obtain equally good results in practice. In the third study, correlated prediction errors were identified as the plausible reason for this. The higher the correlations the less was found to be gained by applying DA. Despite several remaining challenges, the overall conclusion is that DA has a potential to make forest inventories more efficient in the future

Protection over mobility? How shell selection in the hermit crab Clibanarius erythropus (Paguroidea) is modulated by availability and ecological conditions.

Hermit crabs occupy empty gastropods shells, which have to provide both: mobility and protection. Yet, the process of shell selection and the preference for different architectural traits, such as globose or conical shapes, has not been fully understood. In this study we look into the selection behaviour of Clibanarius erythropus. Five gastropod shell types of similar size were offered in a laboratory setup. The results were compared to findings in a natural habitat in Le Cabellou, located on the French Atlantic Coast. Moreover, the radius of movement between consecutive tides was studied to infer how C. erythropus obtains shells in the absence of live gastropods. When offered in equal amounts, a vast majority selected a shell of conical shape as a final shelter, either Tritia reticulata or, to a lesser extent, Nucella lapillus. Consistent with this, these two gastropods provided the shells first selected and occupied the most time during the experiment. A similar preference for a conical shape was observed in the field. Yet, a greater fraction was found to occupy N. lapillus. Moreover, after two tides, 47 % of specimens were recovered in close vicinity to their original location. Due to this locational constancy we presume that the population depends on a passive import of certain shells. The different abundance of empty gastropod shells is likely to constitute a limiting factor that modulates shell selection under natural conditions. As a consistent result in the laboratory and the field, a clear preference for a conical shape over globose shells was identified. Although impeding mobility, this architectural trait has been discussed as providing a better protection from predation. Additionally we explain how a conical shape might be beneficial under strong hydrodynamic action, as found at Le Cabellou. Shell preference might therefore be regarded as less species-specific and more of a response to ecological conditions than previously assumed.Einsiedlerkrebse besetzen leere Schneckenschalen, die beides bieten müssen: Mobilität und Schutz. Der Prozess der Schalenauswahl und die Bevorzugung unterschiedlicher architektonischer Merkmale, wie z oder konische Formen, wurde noch nicht vollständig verstanden. In dieser Studie untersuchen wir das Selektionsverhalten von Clibanarius erythropus. Fünf Schneckenschalentypen ähnlicher Größe wurden in einem Laboraufbau angeboten. Die Ergebnisse wurden mit Befunden in einem natürlichen Lebensraum in Le Cabellou verglichen, der an der französischen Atlantikküste. Darüber hinaus wurde der Bewegungsradius zwischen aufeinanderfolgenden Gezeiten untersucht, um abzuleiten, wie C. erythropus erhält Schalen in Abwesenheit von lebenden Schnecken. Bei gleichem Angebot wählte die überwiegende Mehrheit eine kegelförmige Schale als endgültigen Schutz, entweder Tritia reticulata oder in geringerem Maße Nucella lapillus. In Übereinstimmung damit lieferten diese beiden Schnecken die zuerst ausgewählten Schalen und nahmen während des Experiments die meiste Zeit ein. Eine ähnliche Präferenz für eine konische Form wurde im Feld beobachtet. Es wurde jedoch festgestellt, dass ein größerer Anteil N. lapillus besetzt. Darüber hinaus wurden nach zwei Gezeiten 47 % der Exemplare in unmittelbarer Nähe ihres ursprünglichen Standorts geborgen. Aufgrund dieser Standortkonstanz gehen wir davon aus, dass die Population auf einen passiven Import bestimmter Muscheln angewiesen ist. Die unterschiedliche Häufigkeit leerer Schneckenschalen dürfte ein limitierender Faktor sein, der die Schalenauswahl unter natürlichen Bedingungen moduliert. Als konsistentes Ergebnis im Labor und im Feld wurde eine klare Bevorzugung einer konischen Form gegenüber kugeligen Schalen festgestellt. Obwohl diese architektonische Eigenschaft die Mobilität behindert, wurde diskutiert, dass sie einen besseren Schutz vor Prädation bietet. Darüber hinaus erklären wir, wie eine konische Form bei starker hydrodynamischer Wirkung von Vorteil sein kann, wie sie bei Le Cabellou gefunden wird. Die Schalenpräferenz könnte daher als weniger artspezifisch und stärker als Reaktion auf ökologische Bedingungen angesehen werden als bisher angenommen.Peer Reviewe

Deriving the exhumation history of the Alps with thermochronological data

Thermochronology is a unique tool to derive the exhumation history of rocks over millions of years. Exhumation in orogens is largely controlled by tectonic structures that formed during convergence. Therefore, thermochronological data can be used to reconstruct the geodynamic evolution of mountain ranges and, more precisely, the activity of large fault systems. The Alps are one of the best-studied mountain ranges, with several thousands of low-temperature thermochronological samples dated with a variety of methods (e.g. Herrman et al. 2013; Fox et al. 2015). In this study, we review the most recent thermochronological literature to summarise the exhumation history of the Alps and discuss their driving forces. The apatite (U-Th)/He system is sensitive to the most recent exhumation (closure temperature of ~60°C) and records in places the (over-)deepening and widening of valleys around the Alps (e.g., Valla et al. 2011; Glotzbach et al. 2011). The higher temperature systems, especially the ZFT system (closure temperature of ~240°C), reveal the location of deeper exhumation (>10 km) caused by large-scale fault activity (Fig. 1). While some parts of the Southern Alps and the northern part of the Western and Eastern Alps were not reset during the Alpine orogeny, most of the internal parts of the Alps reveal reset ZFT ages (Fig. 1). The timing of exhumation of these regions, however, varies significantly with distinct tectonic regions. The most recent ZFT ages are <15 Ma and located in the external crystalline massifs, the Lepontine Dome, and the Tauern Window. The latter two are exhumed by large-scale orogen-parallel extensional faulting and contemporaneous indentation. This event ceased in middle Miocene times when faulting and associated exhumation switched towards the Southern Alps (e.g. Eizenhöfer et al. 2021). Apatite fission-track ages (closure temperature of ~110°C) are the youngest (≤6 Ma) in the external crystalline massifs and record a long-lasting Miocene exhumation, whereas the early Miocene exhumation was caused by vertical tectonics related to rollback of the subducted European slab (e.g. Herwegh et al. 2017; 2019). Ongoing middle to late Miocene exhumation of the external crystalline massifs was instead related to in-sequence thrusting (Herwegh et al. 2019). The young thermochronological ages and related high post-Miocene exhumation in the western external crystalline massifs might be at least partly related to uplift caused by slab detachment (e.g. Fox et al. 2015). In the Eastern Alps, there is no evidence for comparable young (post-Miocene) exhumation ‘hotspots’, suggesting a rather stable geodynamic state and absence of large-scale changes in mantle processes

Constraining the geodynamic evolution of the Alps with sedimentary provenance and detrital thermochronometer data, II. Detrital thermochronology

This project was designed to disentangle sedimentary signals controlled by changes in the lithosphere, the upper crust, and climate change in the European Alps. The hypothesis was that if lithospheric reorganisation in the Alps (such as slab break-off or tearing) occurred, it would lead to spatio-temporal changes in buoyancy, influencing the location of rock uplift and erosion. Specifically, we wanted to test this hypothesis using a multi-proxy provenance approach (sedimentary provenance tools, detrital thermochronology) at key stratigraphic time slices (28, 25, 20, 17, 15, and 12 Ma) from the northern and southern foreland basins. Foreland basin deposits represent a rich archive of erosional processes controlled by tectonics, climate, and lithology. This presentation concerns part II of the study, the detrital thermochronology, which we use as "tracer thermochronology". Applications of tracer thermochronology exploit a known or assumed surface thermochronometric age map (based on either interpolated observed or modelled bedrock ages) to determine the provenance of detrital grains within fluvial or glacial catchments. The goal is to interpret the erosion pattern and processes within the sampled catchment. Before reconstructing and interpreting past erosion patterns and exhumation from detrital zircon fission-track (ZFT) age distributions and modelled bedrock ZFT ages back in time, we produce a frame of reference for today's situation. We do this by investigating signals from 26 modern river samples (21 previous [1,2] and nine new samples) and the present-day erosion pattern and mineral fertility in the Alps. We discuss observed and predicted (based on possible erosion scenarios) ZFT age distributions and potential pitfalls of the method (such as poor bedrock control in some areas of the Alps and challenges in combining previous and new data). Modern river results are consistent for adjacent, similar-size catchments and with expected erosion patterns. Most samples show a higher proportion of younger ZFT ages than would be predicted for uniform erosion and zircon fertility scenarios. Furthermore, we show preliminary results from stratigraphic sections from north and south of the Alps

High-Density Lipoprotein Metabolism in Human Apolipoprotein B\u3csub\u3e100\u3c/sub\u3e Transgenic/Brown Adipose Tissue Deficient Mice: A Model of Obesity-Induced Hyperinsulinemia

Obese and diabetic humans display decreased plasma high-density lipoprotein cholesterol (HDL-C) concentrations and an increased risk for coronary heart disease. However, investigation on HDL metabolism in obesity with a particular emphasis on hepatic ATP-binding cassette transporter A1 (ABCA1), the primary factor for HDL formation, has not been well studied. Human apolipoprotein B100 transgenic (hApoBtg) and brown adipose tissue deficient (BATless) mice were crossed to generate hApoBtg/BATless mice. Male and female hApoBtg and hApoBtg/BATless mice were maintained on either a regular rodent chow diet or a diet high in fat and cholesterol until 24 weeks of age. The hApoBtg/BATless mice that were fed a HF/HC diet became obese, developed hepatic steatosis, and had significantly elevated plasma insulin levels compared with their hApoBtg counterparts, but plasma concentrations of total cholesterol, HDL-C, triglycerides, and free fatty acids and lipoprotein distribution between genotypes were not significantly different. Hepatic expression of genes encoding HDL-modifying factors (e.g., scavenger receptor, class B, type I, hepatic lipase, lecithin:cholesterol acyltransferase, and phospholipid transfer protein) was either altered significantly or showed a trend of difference between 2 genotypes of mice. Importantly, hepatic protein levels of ABCA1 were significantly lowered by ∼35% in male obese hApoBtg/BATless mice with no difference in mRNA levels compared with hApoBtg counterparts. Despite reduced hepatic ABCA1 protein levels, plasma HDL-C concentrations were not altered in male obese hApoBtg/BATless mice. The result suggests that hepatic ABCA1 may not be a primary contributing factor for perturbations in HDL metabolism in obesity-induced hyperinsulinemia

Assessing Error Correlations in Remote Sensing-Based Estimates of Forest Attributes for Improved Composite Estimation

Today, non-expensive remote sensing (RS) data from different sensors and platforms can be obtained at short intervals and be used for assessing several kinds of forest characteristics at the level of plots, stands and landscapes. Methods such as composite estimation and data assimilation can be used for combining the different sources of information to obtain up-to-date and precise estimates of the characteristics of interest. In composite estimation a standard procedure is to assign weights to the different individual estimates inversely proportional to their variance. However, in case the estimates are correlated, the correlations must be considered in assigning weights or otherwise a composite estimator may be inefficient and its variance be underestimated. In this study we assessed the correlation of plot level estimates of forest characteristics from different RS datasets, between assessments using the same type of sensor as well as across different sensors. The RS data evaluated were SPOT-5 multispectral data, 3D airborne laser scanning data, and TanDEM-X interferometric radar data. Studies were made for plot level mean diameter, mean height, and growing stock volume. All data were acquired from a test site dominated by coniferous forest in southern Sweden. We found that the correlation between plot level estimates based on the same type of RS data were positive and strong, whereas the correlations between estimates using different sources of RS data were not as strong, and weaker for mean height than for mean diameter and volume. The implications of such correlations in composite estimation are demonstrated and it is discussed how correlations may affect results from data assimilation procedures

Lipid Extract of \u3ci\u3eNostoc commune\u3c/i\u3e var. \u3ci\u3esphaeroides\u3c/i\u3e Kützing, a Blue-Green Alga, Inhibits the Activation of Sterol Regulatory Element Binding Proteins in HepG2 Cells

Nostoc commune var. sphaeroides Kützing (N. commune), a blue-green alga, has been used as both a food ingredient and in medicine for centuries. To determine the effect of N. commune on cholesterol metabolism, N. commune lipid extract was incubated at increasing concentrations (25–100 mg/L) with HepG2 cells, a human hepatoma cell line. The addition of N. commune lipid extract markedly reduced mRNA abundance of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) and LDL receptor (LDLR) (P \u3c 0.05), with a concomitant decrease in their protein expression (P \u3c 0.001). Reduced HMGR activity by 90% with N. commune lipid extract confirmed the inhibitory role of N. commune in cholesterol synthesis (P \u3c 0.006). To elucidate a molecular mechanism underlying the repression of HMGR and LDLR by N. commune lipid extract, expression of sterol regulatory element binding protein 2 (SREBP-2) was assessed. Whereas mRNA for SREBP-2 remained unchanged, SREBP-2 mature protein was reduced by N. commune (P \u3c 0.009). In addition, N. commune lipid extract also decreased SREBP-1 mature protein by ~30% (P \u3c 0.002) and reduced the expression of SREBP-1-responsive genes such as fatty acid synthase and stearoyl CoA desaturase 1 (SCD-1) (P \u3c 0.05). Therefore, our results demonstrate that N. commune lipid extract inhibits the maturation process of both SREBP-1 and -2, resulting in a decrease in expression of genes involved in cholesterol and fatty acid metabolism

A longitudinal examination of heart-rate and heart rate variability as risk markers for child posttraumatic stress symptoms in an acute injury sample

Heart rate (HR) alterations in the immediate aftermath of trauma-exposure have been proposed to be potentially useful markers for child and adolescent posttraumatic stress disorder (PTSD). However, it is not yet clear if this holds true for measures taken more distal to the trauma, and no studies have investigated the predictive validity of more sensitive HR variability (HRV) indices. We recruited 76 parent-child pairs (child age 6 to 13 years) after the child experienced a traumatic event leading to presentation at a hospital emergency department. At 1-month post trauma (T1), HR recordings were obtained at rest, and while children verbally recounted their traumatic experience, both alone and together with a parent. Child post-traumatic stress symptoms (PTSS) were assessed concurrently (T1), and at 3 (T2) and 6-month (T3) follow-ups. We found that for T1, elevated mean HR during trauma narratives, but not at baseline, was positively associated with PTSS, with some evidence that HRV-indices were negatively cross-sectionally associated with PTSS. Furthermore, T1 HR indices predicted PTSS at T2 and partially at T3, although these effects did not hold when T1 PTSS were added to the model. Findings suggest that, consistent with the adult literature, HR indices in children may be a concurrent marker of higher PTSS and may be predictive of longer term distress. The findings encourage further investigations that track child HR and HRV in relation to PTSS over time after trauma, in order to examine how biological profiles evolve in those with persistent symptoms

Aquatic Polyphaga (Insecta: Coleoptera) from Kampong Speu Province, Cambodia

We present the results of a faunistic inventory undertaken on aquatic Polyphaga beetles as part of a workshop organised by the BIO-PHIL project in Cambodia. Three small rivers and a pond in Kampong Speu Province were sampled in July 2018. Twenty-one taxa were collected during the sampling and identifi ed to species or morphospecies level. These are described with comments on habitat, distribution and further remarks, where applicable. A checklist of the genera and species of aquatic Dryopidae, Elmidae, Hydraenidae, Hydrophilidae, Psephenidae and Spercheidae of Cambodia is presented which includes new records for the countr