WorldCat Identities

Albert-Ludwigs-Universität Freiburg Geobotany

Works: 4 works in 4 publications in 2 languages and 10 library holdings
Roles: Contributor
Publication Timeline
Most widely held works by Albert-Ludwigs-Universität Freiburg
Environmental drivers of Ixodes ricinus abundance in forest fragments of rural European landscapes by Steffen Ehrmann( )

1 edition published in 2017 in English and held by 3 WorldCat member libraries worldwide

Abstract: Background: The castor bean tick (Ixodes ricinus) transmits infectious diseases such as Lyme borreliosis, which constitutes an important ecosystem disservice. Despite many local studies, a comprehensive understanding of the key drivers of tick abundance at the continental scale is still lacking. We analyze a large set of environmental factors as potential drivers of I. ricinus abundance. Our multi-scale study was carried out in deciduous forest fragments dispersed within two contrasting rural landscapes of eight regions, along a macroclimatic gradient stretching from southern France to central Sweden and Estonia. We surveyed the abundance of I. ricinus, plant community composition, forest structure and soil properties and compiled data on landscape structure, macroclimate and habitat properties. We used linear mixed models to analyze patterns and derived the relative importance of the significant drivers.<br><br>Results: Many drivers had, on their own, either a moderate or small explanatory value for the abundance of I. ricinus, but combined they explained a substantial part of variation. This emphasizes the complex ecology of I. ricinus and the relevance of environmental factors for tick abundance. Macroclimate only explained a small fraction of variation, while properties of macro- and microhabitat, which buffer macroclimate, had a considerable impact on tick abundance. The amount of forest and the composition of the surrounding rural landscape were additionally important drivers of tick abundance. Functional (dispersules) and structural (density of tree and shrub layers) properties of the habitat patch played an important role. Various diversity metrics had only a small relative importance. Ontogenetic tick stages showed pronounced differences in their response. The abundance of nymphs and adults is explained by the preceding stage with a positive relationship, indicating a cumulative effect of drivers.<br><br>Conclusions: Our findings suggest that the ecosystem disservices of tick-borne diseases, via the abundance of ticks, strongly depends on habitat properties and thus on how humans manage ecosystems from the scale of the microhabitat to the landscape. This study stresses the need to further evaluate the interaction between climate change and ecosystem management on I. ricinus abundance
Late neolithic agriculture in temperate Europe--a long-term experimental approach by M Rösch( )

1 edition published in 2017 in English and held by 3 WorldCat member libraries worldwide

Abstract: Long-term slash-and-burn experiments, when compared with intensive tillage without manuring, resulted in a huge data set relating to potential crop yields, depending on soil quality, crop type, and agricultural measures. Cultivation without manuring or fallow phases did not produce satisfying yields, and mono-season cropping on freshly cleared and burned plots resulted in rather high yields, comparable to those produced during modern industrial agriculture - at least ten-fold the ones estimated for the medieval period. Continuous cultivation on the same plot, using imported wood from adjacent areas as fuel, causes decreasing yields over several years. The high yield of the first harvest of a slash-and-burn agriculture is caused by nutrient input through the ash produced and mobilization from the organic matter of the topsoil, due to high soil temperatures during the burning process and higher topsoil temperatures due to the soil's black surface. The harvested crops are pure, without contamination of any weeds. Considering the amount of work required to fight weeds without burning, the slash-and-burn technique yields much better results than any other tested agricultural approach. Therefore, in dense woodland, without optimal soils and climate, slash-and-burn agriculture seems to be the best, if not the only, feasible method to start agriculture, for example, during the Late Neolithic, when agriculture expanded from the loess belt into landscapes less suitable for agriculture. Extensive and cultivation with manuring is more practical in an already-open landscape and with a denser population, but its efficiency in terms of the ratio of the manpower input to food output, is worse. Slash-and-burn agriculture is not only a phenomenon of temperate European agriculture during the Neolithic, but played a major role in land-use in forested regions worldwide, creating anthromes on a huge spatial scale
Pitfalls in root trait calculations: how ignoring diameter heterogeneity can lead to overestimation of functional traits by Laura Rose( )

1 edition published in 2017 in English and held by 2 WorldCat member libraries worldwide

Abstract: Specific root length (SRL) and root tissue density (RTD) are ecologically functional traits which are calculated from root length or volume and root dry weight. Both can be converted into each other using the root diameter assuming roots are cylindrical. The calculation of volume from length or length from volume is, however, problematic because samples of roots do usually not have a constant diameter. Ignorance of the diameter heterogeneity leads to an overestimation of length and an underestimation of volume if standard formulas are used. Here I show for two datasets that SRL and RTD are overestimated on average 67% for the two analyzed datasets, but up to 150%, if calculated from each other. I further highlight that the volume values for the total sample as provided by the commonly used software WinRHIZOTM should only be used for objects with constant diameter. I recommend to use volume values provided for each diameter class of a sample if WinRHIZOTM is used. If manual methods, like the line-intersect method, are used, roots should be separated into diameter classes before length measurements if the volume is calculated from length. Trait to trait conversions for whole samples are not recommended
Die Entwicklung und Erprobung einer kostengünstigen Methode zur Erfassung der raumzeitlichen Variation von photosynthetisch aktiver Strahlung by Max Metzger( )

1 edition published in 2016 in German and held by 2 WorldCat member libraries worldwide

Audience Level
Audience Level
  Kids General Special  
Audience level: 0.95 (from 0.95 for Environmen ... to 0.95 for Environmen ...)

Alternative Names
Albert-Ludwigs-Universität Freiburg Abteilung Geobotanik

Albert-Ludwigs-Universität Freiburg Institut für Biologie 2 Geobotany

Albert-Ludwigs-Universität Freiburg Lehrstuhl Geobotanik

University of Freiburg Department of Geobotany at the Faculty of Biology

University of Freiburg Faculty of Biology Geobotany