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121 result(s) for "KOLB, ANNETTE"
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Latitudinal gradients as natural laboratories to infer species' responses to temperature
1. Macroclimatic variation along latitudinal gradients provides an excellent natural laboratory to investigate the role of temperature and the potential impacts of climate warming on terrestrial organisms. 2. Here, we review the use of latitudinal gradients for ecological climate change research, in comparison with altitudinal gradients and experimental warming, and illustrate their use and caveats with a meta-analysis of latitudinal intraspecific variation in important life-history traits of vascular plants. 3. We first provide an overview of latitudinal patterns in temperature and other abiotic and biotic environmental variables in terrestrial ecosystems. We then assess the latitudinal intraspecific variation present in five key life-history traits [plant height, specific leaf area (SLA), foliar nitrogen: phosphorus (N:P) stoichiometry, seed mass and root: shoot (R:S) ratio] in natural populations or common garden experiments across a total of 98 plant species. 4. Intraspecific leaf N:P ratio and seed mass significantly decreased with latitude in natural populations. Conversely, the plant height decreased and SLA increased significantly with latitude of population origin in common garden experiments. However, less than a third of the investigated latitudinal transect studies also formally disentangled the effects of temperature from other environmental drivers which potentially hampers the translation from latitudinal effects into a temperature signal. 5. Synthesis. Latitudinal gradients provide a methodological set-up to overcome the drawbacks of other observational and experimental warming methods. Our synthesis indicates that many lifehistory traits of plants vary with latitude but the translation of latitudinal clines into responses to temperature is a crucial step. Therefore, especially adaptive differentiation of populations and confounding environmental factors other than temperature need to be considered. More generally, integrated approaches of observational studies along temperature gradients, experimental methods and common garden experiments increasingly emerge as the way forward to further our understanding of species and community responses to climate warming.
Effects of Life-History Traits on Responses of Plant Species to Forest Fragmentation
Knowing the general principles of plant-environment relationships is required to be able to predict changes in species occurrence and abundance in changing landscapes. Because habitat fragmentation may affect the dispersal, establishment, and persistence of species in various ways, we expected associations between species life-history traits related to these processes and their responses to fragmentation. We tested (1) whether groups of plant species with specific biological attributes are especially affected by forest fragmentation and (2) whether regionally rare species are more negatively affected than more common species. We surveyed 145 deciduous forest patches in northwestern Germany for the presence of a large set of forest plant species. For each of 82 species, we collected data on eight life-history traits and estimated species' responses to decreased patch size and increased distance to other occupied forest patches. We classified species into two emergent groups that differed strongly with respect to most considered life-history traits. The group of species that was more negatively affected by isolation mostly consisted of clonal forest specialist species characterized by few and heavy diaspores, lack of dispersal structures, small size, short-lived seeds, and insect pollination. There was no effect of patch area. Univariate analyses revealed (marginally) significant relationships between species' responses to isolation and diaspore number and mass, plant height, and habitat preference and between responses to patch area and seed-bank longevity, plant height, and habitat preference. Regional frequency of occurrence was not correlated to species' responses to fragmentation and did not differ between the two emergent groups. Rare species, however, were smaller and produced fewer and shorter-lived diaspores than common species. Forest fragmentation may thus threaten species differently, depending on their specific biological characteristics. Approaches based on life-history traits potentially allow prediction of species' responses to habitat fragmentation and may therefore aid in the assessment of the endangerment of plant species and ultimately in the conservation of biological diversity.
The taxonomist - an endangered race. A practical proposal for its survival
Background Taxonomy or biological systematics is the basic scientific discipline of biology, postulating hypotheses of identity and relationships, on which all other natural sciences dealing with organisms relies. However, the scientific contributions of taxonomists have been largely neglected when using species names in scientific publications by not citing the authority on which they are based. Discussion Consequences of this neglect is reduced recognition of the importance of taxonomy, which in turn results in diminished funding, lower interest from journals in publishing taxonomic research, and a reduced number of young scientists entering the field. This has lead to the so-called taxonomic impediment at a time when biodiversity studies are of critical importance. Here we emphasize a practical and obvious solution to this dilemma. We propose that whenever a species name is used, the author(s) of the species hypothesis be included and the original literature source cited, including taxonomic revisions and identification literature - nothing more than what is done for every other hypothesis or assumption included in a scientific publication. In addition, we postulate that journals primarily publishing taxonomic studies should be indexed in ISI SM . Summary The proposal outlined above would make visible the true contribution of taxonomists within the scientific community, and would provide a more accurate assessment for funding agencies impact and importance of taxonomy, and help in the recruitment of young scientists into the field, thus helping to alleviate the taxonomic impediment. In addition, it would also make much of the biological literature more robust by reducing or alleviating taxonomic uncertainty.
Misperceived invasion: the Lusitanian slug (Arion lusitanicus auct. non‐Mabille or Arion vulgaris Moquin‐Tandon 1855) is native to Central Europe
The Lusitanian slug, presumed to be native to south‐west Europe, was ranked among the 100 worst invading species in Central Europe. However, from the very beginning of its recognition in the presumed invasion area, there was little evidence that the species was actually anthropogenically introduced. We investigated the invasive status of the species by comparing specific predictions on the population genetic structure in the invasion area with the pattern actually found. In a DNA‐taxonomy approach, the species could not be found in its presumed native range. Using statistical phylogeographic techniques on a mitochondrial (COI) and nuclear (ZF) marker and species distribution modelling, we could show that the species is with very high probability not an invasor, but native to Central Europe. The study underlines the value of statistical phylogeography in rigorously testing hypotheses on the dynamics of biological invasions.
Evolution of microgastropods (Ellobioidea, Carychiidae): integrating taxonomic, phylogenetic and evolutionary hypotheses
Background Current biodiversity patterns are considered largely the result of past climatic and tectonic changes. In an integrative approach, we combine taxonomic and phylogenetic hypotheses to analyze temporal and geographic diversification of epigean ( Carychium ) and subterranean ( Zospeum ) evolutionary lineages in Carychiidae (Eupulmonata, Ellobioidea). We explicitly test three hypotheses: 1) morphospecies encompass unrecognized evolutionary lineages, 2) limited dispersal results in a close genetic relationship of geographical proximally distributed taxa and 3) major climatic and tectonic events had an impact on lineage diversification within Carychiidae. Results Initial morphospecies assignments were investigated by different molecular delimitation approaches (threshold, ABGD, GMYC and SP). Despite a conservative delimitation strategy, carychiid morphospecies comprise a great number of unrecognized evolutionary lineages. We attribute this phenomenon to historic underestimation of morphological stasis and phenotypic variability amongst lineages. The first molecular phylogenetic hypothesis for the Carychiidae (based on COI, 16S and H3) reveals Carychium and Zospeum to be reciprocally monophyletic. Geographical proximally distributed lineages are often closely related. The temporal diversification of Carychiidae is best described by a constant rate model of diversification. The evolution of Carychiidae is characterized by relatively few (long distance) colonization events. We find support for an Asian origin of Carychium . Zospeum may have arrived in Europe before extant members of Carychium . Distantly related Carychium clades inhabit a wide spectrum of the available bioclimatic niche and demonstrate considerable niche overlap. Conclusions Carychiid taxonomy is in dire need of revision. An inferred wide distribution and variable phenotype suggest underestimated diversity in Zospeum . Several Carychium morphospecies are results of past taxonomic lumping. By collecting populations at their type locality, molecular investigations are able to link historic morphospecies assignments to their respective evolutionary lineage. We propose that rare founder populations initially colonized a continent or cave system. Subsequent passive dispersal into adjacent areas led to in situ pan-continental or mountain range diversifications. Major environmental changes did not influence carychiid diversification. However, certain molecular delimitation methods indicated a recent decrease in diversification rate. We attribute this decrease to protracted speciation.
An update on Peginterferon beta-1a Management in Multiple Sclerosis: results from an interdisciplinary Board of German and Austrian Neurologists and dermatologists
Background Interferon (IFN) beta drugs have been approved for the treatment of relapsing forms of multiple sclerosis (RMS) for more than 20 years and are considered to offer a favourable benefit-risk profile. In July 2014, subcutaneous (SC) peginterferon beta-1a 125 μg dosed every 2 weeks, a pegylated form of interferon beta-1a, was approved by the EMA for the treatment of adult patients with RRMS and in August 2014 by the FDA for RMS. Peginterferon beta-1a shows a prolonged half-life and increased systemic drug exposure resulting in a reduced dosing frequency compared to other available interferon-based products in MS. In the Phase 3 ADVANCE trial peginterferon beta-1a demonstrated significant positive effects on clinical and MRI outcome measures versus placebo after one year. Furthermore, in the ATTAIN extension study, sustained efficacy with long-term treatment for nearly 6 years was shown. Main text In July 2016, an interdisciplinary panel of German and Austrian experts convened to discuss the management of side effects associated with peginterferon beta-1a and other interferon beta-based treatments in MS in daily practice. The panel was composed of experts from university hospitals and private clinics comprised of neurologists, dermatologists, and an MS nurse. In this paper we report recommendations regarding best practices for adverse event management, focussing on peginterferon beta-1a. Injection site reactions (ISRs) and influenza-like illness are the most common adverse effects of interferon beta therapies and can present a burden for MS patients leading to non-adherence and discontinuation of therapy. Peginterferon beta-1a shows improved pharmacological properties. In clinical trials, the adverse event (AE) profile of peginterferon beta-1a was similar to other interferon beta formulations. The most common AEs were mild to moderate ISRs, influenza-like illness, pyrexia, and headache. Current information on the underlying cause of skin reactions associated with SC interferon treatment, and the management strategies for these AEs are limited. In pivotal trials, ISRs were mainly characterized and classified by neurologists, while dermatologists were only rarely consulted. Conclusions This report addresses expert recommendations on the management of most relevant adverse effects related to peginterferon beta-1a and other interferon betas, based on literature and interdisciplinary experience.
Homogenization of forest plant communities and weakening of species-environment relationships via agricultural land use
1 Disturbance may cause community composition across sites to become more or less homogenous, depending on the importance of different processes involved in community assembly. In north-eastern North America and Europe local (alpha) diversity of forest plants is lower in forests growing on former agricultural fields (recent forests) than in older (ancient) forests, but little is known about the influence of land-use history on the degree of compositional differentiation among sites (beta diversity). 2 Here we analyse data from 1446 sites in ancient and recent forests across 11 different landscapes in north-eastern North America and Europe to demonstrate decreases in beta diversity and in the strength of species-environment relationships in recent vs. ancient forests. 3 The magnitude of environmental variability among sites did not differ between the two forest types. This suggests the difference in beta diversity between ancient and recent forests was not due to different degrees of environmental heterogeneity, but rather to dispersal filters that constrain the pool of species initially colonizing recent forests. 4 The observed effects of community homogenization and weakened relationships between species distributions and environmental gradients appear to persist for decades or longer. The legacy of human land-use history in spatial patterns of biodiversity may endure, both within individual sites and across sites, for decades if not centuries.
Evolution of leaf warbler songs (Aves: Phylloscopidae)
Songs in passerine birds are important for territory defense and mating. Speciation rates in oscine passerines are so high, due to cultural evolution, that this bird lineage makes up half of the extant bird species. Leaf warblers are a speciose Old‐World passerine family of limited morphological differentiation, so that songs are even more important for species delimitation. We took 16 sonographic traits from song recordings of 80 leaf warbler taxa and correlated them with 15 potentially explanatory variables, pairwise, and in linear models. Based on a well‐resolved molecular phylogeny of the same taxa, all pairwise correlations were corrected for relatedness with phylogenetically independent contrasts and phylogenetic generalized linear models were used. We found a phylogenetic signal for most song traits, but a strong one only for the duration of the longest and of the shortest element, which are presumably inherited instead of learned. Body size of a leaf warbler species is a constraint on song frequencies independent of phylogeny. At least in this study, habitat density had only marginal impact on song features, which even disappeared through phylogenetic correction. Maybe most leaf warblers avoid the deterioration through sound propagation in dense vegetation by singing from exposed perches. Latitudinal (and longitudinal) extension of the breeding ranges was correlated with most song features, especially verse duration (longer polewards and westwards) and complexity (lower polewards). Climate niche or expansion history might explain these correlations. The number of different element types per verse decreases with elevation, possibly due to fewer resources and congeneric species at higher elevations. Song recordings of 80 leaf warbler taxa were analysed and 16 sonographic traits correlated with 15 potentially explanatory variables, correcting for phylogenetic relationships. A strong phylogenetic signal was only found for two element traits. Frequencies were correlated with body size, many other traits with various biogeographic attributes.
Habitat properties are key drivers of Borrelia burgdorferi (s.l.) prevalence in Ixodes ricinus populations of deciduous forest fragments
Background: The tick Ixodes ricinus has considerable impact on the health of humans and other terrestrial animals because it transmits several tick-borne pathogens (TBPs) such as B. burgdorferi (sensu lato), which causes Lyme borreliosis (LB). Small forest patches of agricultural landscapes provide many ecosystem services and also the disservice of LB risk. Biotic interactions and environmental filtering shape tick host communities distinctively between specific regions of Europe, which makes evaluating the dilution effect hypothesis and its influence across various scales challenging. Latitude, macroclimate, landscape and habitat properties drive both hosts and ticks and are comparable metrics across Europe. Therefore, we instead assess these environmental drivers as indicators and determine their respective roles for the prevalence of B. burgdorferi in I. ricinus.Methods: We sampled I. ricinus and measured environmental properties of macroclimate, landscape and habitat quality of forest patches in agricultural landscapes along a European macroclimatic gradient. We used linear mixed models to determine significant drivers and their relative importance for nymphal and adult B. burgdorferi prevalence. We suggest a new prevalence index, which is pool-size independent.Results: During summer months, our prevalence index varied between 0 and 0.4 per forest patch, indicating a low to moderate disservice. Habitat properties exerted a fourfold larger influence on B. burgdorferi prevalence than macroclimate and landscape properties combined. Increasingly available ecotone habitat of focal forest patches diluted and edge density at landscape scale amplified B. burgdorferi prevalence. Indicators of habitat attractiveness for tick hosts (food resources and shelter) were the most important predictors within habitat patches. More diverse and abundant macro- and microhabitat had a diluting effect, as it presumably diversifies the niches for tick-hosts and decreases the probability of contact between ticks and their hosts and hence the transmission likelihood. Conclusions: Diluting effects of more diverse habitat patches would pose another reason to maintain or restore high biodiversity in forest patches of rural landscapes. We suggest classifying habitat patches by their regulating services as dilution and amplification habitat, which predominantly either decrease or increase B. burgdorferi prevalence at local and landscape scale and hence LB risk. Particular emphasis on promoting LB-diluting properties should be put on the management of those habitats that are frequently used by humans. In the light of these findings, climate change may be of little concern for LB risk at local scales, but this should be evaluated further.
Environmental drivers of Ixodes ricinus abundance in forest fragments of rural European landscapes
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. 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. 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.