First results in modelling distribution patterns of anecic earthworms on catchment scale: a Boosted Regres-sion Tree model approach

Earthworms can serve as indicator species for various important soil processes. Therefore we can link distribution patterns of earthworms to the incidence of induced soil processes. Species distribution models can help us to predict earthworm distributions on different scales. Studies on larger scales are rare due to large efforts in data acquisition, especially if the focus is on process understanding. The current study focuses on anecic earthworms using a Boosted regression tree model approach for predicting the earthworm distribution in an agricultural area in Baden- Württemberg (Germany). We surveyed management, topography, soil parameters and presence-absence, abundance and fresh weight of anecic earthworms (i.e. Lumbricus terrestris) at 75 locations within the Weiherbach catchment. Our final model has acceptable performance (AUC=0.76 after validation). Topographic indices (wetness and Beer’s index) as well as soil parameters such as moisture, texture and tillage are the most relevant environmental predictors

Habitat suitability models for the conservation of thermophilic grasshoppers and bush crickets—simple or complex?

One goal of conservation biology is the assessment of effects of land use change on species distribution. One approach for identifying the factors, which determine habitat suitability for a species are statistical habitat distribution models. These models are quantitative and can be used for predictions in management scenarios. However, they often have one major shortcoming, which is their complexity. This means that they need several, often costly-to-determine parameters for predictions of species occurrence. We first used habitat suitability models to investigate and determine habitat preferences of three different Orthoptera species. Second, we compared the predictive powers of simple habitat suitability models considering only the ‘habitat type' as predictor with more complex models taking different habitat factors into account. We found that the habitat type is the most reliable and robust factor, which determines the occurrence of the species studied. Thus, analyses of habitat suitability can easily be carried out on the basis of existing vegetation maps for the conservation of the three species under study. Our results can serve as a basis for the estimation of spatio-temporal distribution and survival probabilities of the species studied and might also be valuable for other species living in dry grassland

The influence of the geomorphological and sedimentological settings on the distribution of epibenthic assemblages on a flat topped hill on the over-deepened shelf of the western Weddell Sea (Southern Ocean)

Epibenthos communities play an important role in the marine ecosystems of the Weddell Sea. Information on the factors controlling their structure and distribution are, however, still rare. In particular, the interactions between environmental factors and biotic assemblages are not fully understood. Nachtigaller Hill, a newly discovered seabed structure on the over-deepened shelf of the northwest Weddell Sea (Southern Ocean), offers a unique site to study these interactions in a high-latitude Antarctic setting. Based on high-resolution bathymetry and georeferenced biological data, the effect of the terrain and related environmental parameters on the epibenthos was assessed. At Nachtigaller Hill, both geomorphological and biological data showed complex distribution patterns, reflecting local processes such as iceberg scouring and locally amplified bottom currents. This variability was also generally reflected in the variable epibenthos distribution patterns although statistical analyses did not show strong correlations between the selected environmental parameters and species abundances. By analysing the interactions between environmental and biological patterns, this study provides crucial information towards a better understanding of the factors and processes that drive epibenthos communities on the shelves of the Weddell Sea and probably also on other Antarctic shelves

Factors influencing vegetation cover change in Mediterranean Central Chile (1975-2008)

Las figuras y apéndices que contiene el documento se localizan al final del mismo.Questions: Which are the factors that influence forest and shrubland loss and regeneration and their underlying drivers?\ud \ud Location: Central Chile, a world biodiversity hotspot.\ud \ud Methods: Using land-cover data from the years 1975, 1985, 1999 and 2008, we fitted classification trees and multiple logistic regression models to account for the relationship between different trajectories of vegetation change and a range of biophysical and socio-economic factors.\ud \ud Results: The variables that most consistently showed significant effects on vegetation change across all time-intervals were slope and distance to primary roads. We found that forest and shrubland loss on one side and regeneration on the other often displayed opposite patterns in relation to the different explanatory variables. Deforestation was positively related to distance to primary roads and to distance within forest edges and was favoured by a low insolation and a low slope. In turn, forest regeneration was negatively related to the distance to primary roads and positively to the distance to the nearest forest patch, insolation and slope. Shrubland loss was positively influenced by slope and distance to cities and primary roads and negatively influenced by distance to rivers. Conversely, shrubland regeneration was negatively related to slope, distance to cities and distance to primary roads and positively related to distance from existing forest patches and distance to rivers.\ud \ud Conclusions: This article reveals how biophysical and socioeconomic factors influence vegetation cover change and the underlying social, political and economical drivers. This assessment provides a basis for management decisions, considering the crucial role of perennial vegetation cover for sustaining biodiversity and ecosystem services.This work was financed by the REFORLAN Project, INCO Contract CT2006-032132 (European Commission), with additional input from projects CGL2010-18312 (Spanish Ministry of Science and Innovation) and S2009AMB-1783 (Madrid Government REMEDINAL-2). We are in-\ud debted to Javier Salas and Cristian Echeverría for their input in this project. The manuscript benefited from\ud useful comments from Jorge Aubad and two anonymous\ud reviewers, who improved the contents and presentation\ud of this stud

Ion microscopy with evolutionary-algorithm-based autofocusing

Ion microscopy is an established technique for laser focus diagnostics and the accurate, intensity-resolved measurement of laser ionization processes. In the present feasibility study, we discuss a new ion microscope design, which improves its resolution across a large range of magnifications and simplifies its operation. Instead of the common two einzel lens configuration, which is usually optimized for a fixed magnification, we propose a generic design consisting of an array of equally spaced ring electrodes, whose individually adjustable voltages are controlled by an evolutionary algorithm. In this way, we can realize aberration minimized magnifications between 25 and 100. Moreover, the algorithm can adjust the voltage settings under changing experimental conditions and facilitates autofocusing for user-defined magnification

Discrete conformal mappings via circle patterns

We introduce a novel method for the construction of discrete conformal mappings from surface meshes of arbitrary topology to the plane. Our approach is based on circle patterns, that is, arrangements of circles---one for each face---with prescribed intersection angles. Given these angles, the circle radii follow as the unique minimizer of a convex energy. The method supports very flexible boundary conditions ranging from free boundaries to control of the boundary shape via prescribed curvatures. Closed meshes of genus zero can be parameterized over the sphere. To parameterize higher genus meshes, we introduce cone singularities at designated vertices. The parameter domain is then a piecewise Euclidean surface. Cone singularities can also help to reduce the often very large area distortion of global conformal maps to moderate levels. Our method involves two optimization problems: a quadratic program and the unconstrained minimization of the circle pattern energy. The latter is a convex function of logarithmic radius variables with simple explicit expressions for gradient and Hessian. We demonstrate the versatility and performance of our algorithm with a variety of examples

Detecting dominant changes in irregularly sampled multivariate water quality data sets

Time series of groundwater and stream water quality often exhibit substantial temporal and spatial variability, whereas typical existing monitoring data sets, e.g. from environmental agencies, are usually characterized by relatively low sampling frequency and irregular sampling in space and/or time. This complicates the differentiation between anthropogenic influence and natural variability as well as the detection of changes in water quality which indicate changes in single drivers. We suggest the new term "dominant changes" for changes in multivariate water quality data which concern (1) multiple variables, (2) multiple sites and (3) long-term patterns and present an exploratory framework for the detection of such dominant changes in data sets with irregular sampling in space and time. Firstly, a non-linear dimension-reduction technique was used to summarize the dominant spatiotemporal dynamics in the multivariate water quality data set in a few components. Those were used to derive hypotheses on the dominant drivers influencing water quality. Secondly, different sampling sites were compared with respect to median component values. Thirdly, time series of the components at single sites were analysed for long-term patterns. We tested the approach with a joint stream water and groundwater data set quality consisting of 1572 samples, each comprising sixteen variables, sampled with a spatially and temporally irregular sampling scheme at 29 sites in northeast Germany from 1998 to 2009. The first four components were interpreted as (1) an agriculturally induced enhancement of the natural background level of solute concentration, (2) a redox sequence from reducing conditions in deep groundwater to post-oxic conditions in shallow groundwater and oxic conditions in stream water, (3) a mixing ratio of deep and shallow groundwater to the streamflow and (4) sporadic events of slurry application in the agricultural practice. Dominant changes were observed for the first two components. The changing intensity of the first component was interpreted as response to the temporal variability of the thickness of the unsaturated zone. A steady increase in the second component at most stream water sites pointed towards progressing depletion of the denitrification capacity of the deep aquifer

Impact of Temporal Macropore Dynamics on Infiltration : Field Experiments and Model Simulations

Macropores greatly affect water and solute transport in soils. Most macropores are of biogenic origin; however, the resulting seasonal dynamics are often neglected. Our study aimed to examine temporal changes in biopore networks and the resulting infiltration patterns. We performed infiltration experiments with Brilliant Blue on pastureland in the Luxembourgian Attert catchment (spring, summer, and autumn 2015). We developed an image-processing scheme to identify and quantify changes in biopores and infiltration patterns. Subsequently, we used image-derived biopore metrics to parameterize the ecohydrological model echoRD (ecohydrological particle model based on representative domains), which includes explicit macropore flow and interaction with the soil matrix. We used the model simulations to check whether biopore dynamics affect infiltration. The observed infiltration patterns revealed variations in both biopore numbers and biopore–matrix interaction. The field-observed biopore numbers varied over time, mainly in the topsoil, with the largest biopore numbers in spring and the smallest in summer. The number of hydrologically effective biopores in the topsoil seems to determine the number and thereby the fraction of effective biopores in the subsoil. In summer, a strong biopore–matrix interaction was observed. In spring, the dominant process was rapid drainage, whereas in summer and autumn, most of the irrigated water was stored in the examined profiles. The model successfully simulated infiltration patterns for spring, summer, and autumn using temporally different macropore setups. Using a static macropore parameterization the model output deviated from the observed infiltration patterns, which emphasizes the need to consider macropores and their temporal dynamics in soil hydrological modeling

The “Hidden Urbanization”: Trends of Impervious Surface in Low-Density Housing Developments and Resulting Impacts on the Water Balance

Impervious surface is an important factor for the ecological performance of the built environment, in particular for the water balance. Therefore, the rainwater drainage infrastructure of new housing developments is planned according to the expected amount of impervious surface and the resulting surface runoff. Drainage infrastructure could be overwhelmed, however, due to small, dispersed, and often overlooked increases in impervious surface cover, a process we refer to as “hidden urbanization.” There is some evidence that impervious surface cover in housing areas has increased significantly over decades, but is there also a gap between planning and implementation? In order to find out, we compared eight development plans (i.e., the legally binding documents that steer building in Germany) of low-density (single-family) housing with the actual status-quo extracted from 2016 orthophotos. All sites are located in Lower Saxony, Germany; four are close to major urban centers and four are in small municipalities. We then modeled the local water balance for the plans and status-quo and compared results. All sites but one showed a relative increase between 8 and 56% of impervious surface, comparing plans with status-quo. For all sites with an increase of impervious cover, infiltration rates decreased by 4–19%, evaporation rates increased by 0.2–1% and surface runoff increased by 4–18%. In general, the more impervious surface, the stronger the effect. Our results point to a gap between planning and implementation and they underline the environmental consequences, illustrated by effects on the water balance. In order to prevent “hidden urbanization,” we suggest that more emphasis should be put on integrated design of housing areas and monitoring of impervious surface cover

B‐GATA factors are required to repress high‐light stress responses in Marchantia polymorpha and Arabidopsis thaliana

GATAs are evolutionarily conserved zinc-finger transcription factors from eukaryotes. In plants, GATAs can be subdivided into four classes, A–D, based on their DNA-binding domain, and into further subclasses based on additional protein motifs. B-GATAs with a so-called leucine-leucine-methionine (LLM)-domain can already be found in algae. In angiosperms, the B-GATA family is expanded and can be subdivided in to LLM- or HAN-domain B-GATAs. Both, the LLM- and the HAN-domain are conserved domains of unknown biochemical function. Interestingly, the B-GATA family in the liverwort Marchantia polymorpha and the moss Physcomitrium patens is restricted to one and four family members, respectively. And, in contrast to vascular plants, the bryophyte B-GATAs contain a HAN- as well as an LLM-domain. Here, we characterise mutants of the single B-GATA from Marchantia polymorpha. We reveal that this mutant has defects in thallus growth and in gemma formation. Transcriptomic studies uncover that the B-GATA mutant displays a constitutive high-light (HL) stress response, a phenotype that we then also confirm in mutants of Arabidopsis thaliana LLM-domain B-GATAs, suggesting that the B-GATAs have a protective role towards HL stress.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Peer Reviewe