Search results for "Systematics"
showing 10 items of 6702 documents
A Bayesian stable isotope mixing model for coping with multiple isotopes, multiple trophic steps and small sample sizes
2022
We introduce a Bayesian stable isotope mixing model for estimating the relative contributions of different dietary components to the tissues of consumers within food webs. The model is implemented with the probabilistic programming language Stan. The model incorporates isotopes of multiple elements (e.g. C, N, H) for two trophic levels, when the structure of the food web is known. In addition, the model allows inclusion of latent trophic levels (i.e. for which no empirical data are available) intermediate between sources and measured consumers. Running the model in simulations driven by a real dataset from Finnish lakes, we tested the sensitivity of the posterior distributions by altering c…
Comparison of muscle and hair stable isotope ratios in three phocid seals
2020
Camouflage in arid environments: the case of Sahara-Sahel desert rodents
2020
Deserts and semi-deserts, such as the Sahara-Sahel region in North Africa, are exposed environments with restricted vegetation coverage. Due to limited physical surface structures, these open areas provide a promising ecosystem to understand selection for crypsis. Here, we review knowledge on camouflage adaptation in the Sahara-Sahel rodent community, which represents one of the best documented cases of phenotype-environment convergence comprising a marked taxonomic diversity. Through their evolutionary history, several rodent species from the Sahara-Sahel have repeatedly evolved an accurate background matching against visually-guided predators. Top-down selection by predators is therefore …
Interpretation of gut microbiota data in the ‘eye of the beholder’: A commentary and re‐evaluation of data from ‘Impacts of radiation exposure on the…
2021
1.Evidence that exposure to environmental pollutants can alter the gut microbiota composition of wildlife includes studies of rodents exposed to radionuclides. 2.Antwis et al. (2021) used amplicon sequencing to characterise the gut microbiota of four species of rodent (Myodes glareolus, Apodemus agrarius, A. flavicollis and A. sylvaticus) inhabiting the Chernobyl Exclusion Zone (CEZ) to examine possible changes in gut bacteria (microbiota) and gut fungi (mycobiota) associated with exposure to radionuclides and whether the sample type (from caecum or faeces) affected the analysis. 3.The conclusions derived from the analyses of gut mycobiota are based on data that represent a mixture of inges…
Return of the Apex Predator : How Brown Trout (Salmo trutta) Re-Establishment Shapes an Ecosystem
2021
Re-establishment of a declined apex predator fish species in a lake ecosystem may have dramatic effects on other fish and plankton community already inhabiting the ecosystem. We studied mechanistically potential impacts of re-establishment of the brown trout (Salmo trutta) in the west-central European Lake Constance focusing on two commercially important fish species: whitefish and Eurasian perch. We compared simulation model outputs from two versions of an allometric trophic network model for Lake Constance, one with and one without the trout as the apex predator. The re-establishment of the declined brown trout reduced the perch population directly by predation and indirectly by increased…
Environmental context determines pollution impacts on ecosystem functioning
2023
Global change assessments have typically ignored synthetic chemical pollution, despite the rapid increase of pharmaceuticals, pesticides and industrial chemicals in the environment. Part of the problem reflects the multifarious origins of these micropollutants, which can derive from urban and agricultural sources. Understanding how micropollutants harm ecosystems is a major scientific challenge due to asymmetries of stress across trophic levels and ecological surprises generated by multiple drivers interacting in human-impacted landscapes. We used field assays above and below municipal wastewater treatment plants (WWTPs) in 60 sampling locations across 20 Swiss streams to test how micropoll…
Interkingdom Gut Microbiome and Resistome of the Cockroach Blattella germanica
2021
Cockroaches are intriguing animals with two coexisting symbiotic systems, an endosymbiont in the fat body, involved in nitrogen metabolism, and a gut microbiome whose diversity, complexity, role, and developmental dynamics have not been fully elucidated. In this work, we present a metagenomic approach to study Blattella germanica populations not treated, treated with kanamycin, and recovered after treatment, both naturally and by adding feces to the diet, with the aim of better understanding the structure and function of its gut microbiome along the development as well as the characterization of its resistome.
Size-dependent aggression towards kin in a cannibalistic species.
2022
Abstract In juveniles extreme intraspecies aggression can seem counter-intuitive, as it might endanger their developmental goal of surviving until reproductive stage. Ultimately, aggression can be vital for survival, although the factors (e.g., genetic or environmental) leading to the expression and intensity of this behavior vary across taxa. Attacking (and sometimes killing) related individuals may reduce inclusive fitness; as a solution to this problem, some species exhibit kin discrimination and preferentially attack unrelated individuals. Here, we used both experimental and modeling approaches to consider how physical traits (e.g., size in relation to opponent) and genetic relatedness …
Expanding Acutuncus : Phylogenetics and morphological analyses reveal a considerably wider distribution for this tardigrade genus
2023
The tardigrade genus Acutuncus has been long thought to be an Antarctic endemism, well adapted to this harsh environment. The Antarctic endemicity of Acutuncus was recently dispelled with the description of Acutuncus mariae Zawierucha, 2020 found in the Svalbard archipelago. The integrated analyses on two newly found Acutuncus populations from UK and Italy, and a population of Acutuncus antarcticus found close to its type locality allowed us to expand the climatic and geographic range of the genus Acutuncus. These findings also allowed us to re-evaluate the morphological diagnoses of Acutuncus and accommodate it in the newly proposed monotypic family Acutuncidae fam. nov. Two new Acutuncus …
The toughest animals of the Earth versus global warming: Effects of long-term experimental warming on tardigrade community structure of a temperate d…
2021
Abstract Understanding how different taxa respond to global warming is essential for predicting future changes and elaborating strategies to buffer them. Tardigrades are well known for their ability to survive environmental stressors, such as drying and freezing, by undergoing cryptobiosis and rapidly recovering their metabolic function after stressors cease. Determining the extent to which animals that undergo cryptobiosis are affected by environmental warming will help to understand the real magnitude climate change will have on these organisms. Here, we report on the responses of tardigrades within a five‐year‐long, field‐based artificial warming experiment, which consisted of 12 open‐to…