Sebastian Werner results 54
· Newest (Page 1/3, per page 25)
Author: Sebastian Werner ×Clear All Filters
Search Results
Temperate Forest Floors: Ecosystem Hubs in Transition?NARA Subscribed
The forest floor (FF) plays a key role in carbon, nutrient, and water cycling. It is the biologically most active compartment of forest soils, highly responsive to environmental conditions. Yet, its response to current changes in environmental conditions and forest management is understudied. Temperate forests are among the best studied ecosystems globally, providing the necessary ecological and biogeochemical background infor...
Tree Regeneration After Unprecedented Forest Disturbances in Central Europe Is Robust but Maladapted to Future Climate ChangeNARA Subscribed
Central Europe has been a hotspot of forest disturbance during 2018–2020, with large pulses of tree mortality from drought and bark beetles. Post‐disturbance recovery is crucial for forest resilience and the continued provision of ecosystem services. We surveyed 849 plots in disturbance hotspots across 10 Central European countries to assess the state of early (3–5 years) post‐disturbance tree regeneration. Our specific object...
We assessed responses of Arctic Isochrysis sp. grown under a matrix of temperature (2°C vs. 6°C), light intensity (55 vs. 160 μ mol photons m −2 s −1 ) and pCO 2 (400 vs. 1000 μ atm CO 2 ). Next to acclimation parameters (growth rates, particulate and dissolved organic C and N, chlorophyll a content), we measured physiological processes in vivo (electron transport rates and net photosynthesis) using fast‐repetition rate fluoro...
Dominance and rarity in tree communities across the globe: Patterns, predictors and threatsNARA Subscribed
Aim Ecological and anthropogenic factors shift the abundances of dominant and rare tree species within local forest communities, thus affecting species composition and ecosystem functioning. To inform forest and conservation management it is important to understand the drivers of dominance and rarity in local tree communities. We answer the following research questions: (1) What are the patterns of dominance and rarity in tree...
Biological nitrogen fixation, diversity and community structure of diazotrophs in two mosses in 25 temperate forestsNARA Subscribed
Many moss species are associated with nitrogen (N)‐fixing bacteria (diazotrophs) that support the N supply of mosses. Our knowledge relates primarily to pristine ecosystems with low atmospheric N input, but knowledge of biological N fixation (BNF) and diazotrophic communities in mosses in temperate forests with high N deposition is limited. We measured BNF rates using the direct stable isotope method and studied the total and...
We assessed the responses of solitary cells of Arctic Phaeocystis pouchetii grown under a matrix of temperature (2°C vs. 6°C), light intensity (55 vs. 160 μ mol photons m −2 s −1 ) and pCO 2 (400 vs. 1000 μ atm CO 2 , i.e., 40.5 vs. 101.3 Pa). Next to acclimation parameters (growth rates, particulate and dissolved organic C and N, Chlorophyll a content), we measured physiological processes in vivo (electron transport rates and...
Wood decomposition is increased by insect diversity, selection effects, and interactions between insects and microbesNARA Subscribed
Biodiversity drives ecosystem processes, but its influence on deadwood decomposition is poorly understood. To test the effects of insect diversity on wood decomposition, we conducted a mesocosm experiment manipulating the species richness and functional diversity of beetles. We applied a novel approach using computed tomography scanning to quantify decomposition by insects and recorded fungal and bacterial communities. Decompo...
Expansion microscopy in honeybee brains for high-resolution neuroanatomical analyses in social insectsNARA Subscribed
The diffraction limit of light microscopy poses a problem that is frequently faced in structural analyses of social insect brains. With the introduction of expansion microscopy (ExM), a tool became available to overcome this limitation by isotropic physical expansion of preserved specimens. Our analyses focus on synaptic microcircuits (microglomeruli, MG) in the mushroom body (MB) of social insects, high-order brain centers fo...
Ambient and substrate energy influence decomposer diversity differentially across trophic levelsNARA Subscribed
The species‐energy hypothesis predicts increasing biodiversity with increasing energy in ecosystems. Proxies for energy availability are often grouped into ambient energy (i.e., solar radiation) and substrate energy (i.e., non‐structural carbohydrates or nutritional content). The relative importance of substrate energy is thought to decrease with increasing trophic level from primary consumers to predators, with reciprocal eff...
Will forest dynamics continue to accelerate throughout the 21st century in the Northern Alps?NARA Subscribed
Observational evidence suggests that forests in the Northern Alps are changing at an increasing rate as a consequence of climate change. Yet, it remains unclear whether the acceleration of forest change will continue in the future, or whether downregulating feedbacks will eventually decouple forest dynamics from climate change. Here we studied future forest dynamics at Berchtesgaden National Park, Germany by means of a process...
Screening of sugar beet pre-breeding populations and breeding lines for resistance to Ditylenchus dipsaci penetration and reproductionNARA Subscribed
Ditylenchus dipsaci is an economically important plant-parasitic nematode affecting European sugar beets. To date, no sugar beet cultivars carrying resistance against D. dipsaci are available to farmers. To find potentially resistant sugar beet lines restricting reproduction and penetration of D. dipsaci , three consecutive in vivo bioassays were carried out. The first experiment determined the penetration rate of D. dipsaci i...
The stem nematode, Ditylenchus dipsaci , is a severe pest in European sugar beet production. In France, Germany, and Switzerland, D. dipsaci damage in sugar beet varies among specific geographic areas. In this study, the reproduction potential of four geographically distinct D. dipsaci populations was determined using sterile carrot disc cultures. In addition, virulence and pathogenicity were investigated in-vivo using sugar b...
Tropical forests host a remarkable proportion of global arthropod diversity. Yet, arthropod communities living in tropical forests are still poorly studied, particularly for dry forests of Eastern Africa. The aim of this study was to analyse community structures, species richness and relative abundances of insects across a heterogeneous forest consisting of various forest types. We collected insects in the lower canopies with...
Species–area relationships in continuous vegetation: Evidence from Palaearctic grasslandsNARA Subscribed
Aim Species–area relationships (SARs) are fundamental scaling laws in ecology although their shape is still disputed. At larger areas, power laws best represent SARs. Yet, it remains unclear whether SARs follow other shapes at finer spatial grains in continuous vegetation. We asked which function describes SARs best at small grains and explored how sampling methodology or the environment influence SAR shape. Location Palaearct...