| 1. |
- Aad, G, et al.
(författare)
-
- 2015
-
swepub:Mat__t
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Soininen, E.M., et al.
(författare)
-
Location of studies and evidence of effects of herbivory on Arctic vegetation: a systematic map
- 2021
-
Ingår i: Environmental Evidence. - : BioMed Central (BMC). - 2047-2382. ; 10:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Herbivores modify the structure and function of tundra ecosystems. Understanding their impacts is necessary to assess the responses of these ecosystems to ongoing environmental changes. However, the effects of herbivores on plants and ecosystem structure and function vary across the Arctic. Strong spatial variation in herbivore effects implies that the results of individual studies on herbivory depend on local conditions, i.e., their ecological context. An important first step in assessing whether generalizable conclusions can be produced is to identify the existing studies and assess how well they cover the underlying environmental conditions across the Arctic. This systematic map aims to identify the ecological contexts in which herbivore impacts on vegetation have been studied in the Arctic. Specifically, the primary question of the systematic map was: “What evidence exists on the effects of herbivores on Arctic vegetation?”.Methods: We used a published systematic map protocol to identify studies addressing the effects of herbivores on Arctic vegetation. We conducted searches for relevant literature in online databases, search engines and specialist websites. Literature was screened to identify eligible studies, defined as reporting primary data on herbivore impacts on Arctic plants and plant communities. We extracted information on variables that describe the ecological context of the studies, from the studies themselves and from geospatial data. We synthesized the findings narratively and created a Shiny App where the coded data are searchable and variables can be visually explored.Review findings: We identified 309 relevant articles with 662 studies (representing different ecological contexts or datasets within the same article). These studies addressed vertebrate herbivory seven times more often than invertebrate herbivory. Geographically, the largest cluster of studies was in Northern Fennoscandia. Warmer and wetter parts of the Arctic had the largest representation, as did coastal areas and areas where the increase in temperature has been moderate. In contrast, studies spanned the full range of ecological context variables describing Arctic vertebrate herbivore diversity and human population density and impact.Conclusions: The current evidence base might not be sufficient to understand the effects of herbivores on Arctic vegetation throughout the region, as we identified clear biases in the distribution of herbivore studies in the Arctic and a limited evidence base on invertebrate herbivory. In particular, the overrepresentation of studies in areas with moderate increases in temperature prevents robust generalizations about the effects of herbivores under different climatic scenarios.
|
|
| 6. |
- Alcorn, J, et al.
(författare)
-
Basic instrumentation for Hall A at Jefferson Lab
- 2004
-
Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 522:3, s. 294-346
-
Tidskriftsartikel (refereegranskat)abstract
- The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electro-and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. The central components of Hall A are two identical high resolution spectrometers, which allow the vertical drift chambers in the focal plane to provide a momentum resolution of better than 2 x 10(-4). A variety of Cherenkov counters, scintillators and lead-glass calorimeters provide excellent particle identification. The facility has been operated successfully at a luminosity well in excess of 10(38) CM-2 s(-1). The research program is aimed at a variety of subjects, including nucleon structure functions, nucleon form factors and properties of the nuclear medium. (C) 2003 Elsevier B.V. All rights reserved.
|
|
| 7. |
- Klages, J. P., et al.
(författare)
-
Temperate rainforests near the South Pole during peak Cretaceous warmth
- 2020
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 580:7801, s. 81-86
-
Tidskriftsartikel (refereegranskat)abstract
- The mid-Cretaceous period was one of the warmest intervals of the past 140millionyears1–5, driven by atmospheric carbon dioxide levels of around 1,000parts per million by volume6. In the near absence of proximal geological records from south of the Antarctic Circle, it is disputed whether polar ice could exist under such environmental conditions. Here we use a sedimentary sequence recovered from the West Antarctic shelf—the southernmost Cretaceous record reported so far—and show that a temperate lowland rainforest environment existed at a palaeolatitude of about 82°S during the Turonian–Santonian age (92 to 83millionyearsago). This record contains an intact 3-metre-long network of in situ fossil roots embedded in a mudstone matrix containing diverse pollen and spores. A climate model simulation shows that the reconstructed temperate climate at this high latitude requires a combination of both atmospheric carbon dioxide concentrations of 1,120–1,680parts per million by volume and a vegetated land surface without major Antarctic glaciation, highlighting the important cooling effect exerted by ice albedo under high levels of atmospheric carbon dioxide. © 2020, The Author(s), under exclusive licence to Springer Nature Limited.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
- Sheikh, Sanea, et al.
(författare)
-
A New Classification of the Dictyostelids
- 2018
-
Ingår i: Protist. - : Elsevier BV. - 1434-4610 .- 1618-0941. ; 169:1, s. 1-28
-
Tidskriftsartikel (refereegranskat)abstract
- Traditional morphology-based taxonomy of dictyostelids is rejected by molecular phylogeny. A new classification is presented based on monophyletic entities with consistent and strong molecular phylogenetic support and that are, as far as possible, morphologically recognizable. All newly named clades are diagnosed with small subunit ribosomal RNA (18S rRNA) sequence signatures plus morphological synapomorphies where possible. The two major molecular clades are given the rank of order, as Acytosteliales ord. nov. and Dictyosteliales. The two major clades within each of these orders are recognized and given the rank of family as, respectively, Acytosteliaceae and Cavenderiaceae fam. nov. in Acytosteliales, and Dictyosteliaceae and Raperosteliaceae fam. nov. in Dictyosteliales. Twelve genera are recognized: Cavenderia gen. nov. in Cavenderiaceae, Acytostelium, Rostrostelium gen. nov. and Heterostelium gen. nov. in Acytosteliaceae, Tieghemostelium gen. nov., Hagiwaraea gen. nov., Raperostelium gen. nov. and Speleostelium gen. nov. in Raperosteliaceae, and Dictyostelium and Polysphondylium in Dictyosteliaceae. The “polycephalum” complex is treated as Coremiostelium gen. nov. (not assigned to family) and the “polycarpum” complex as Synstelium gen. nov. (not assigned to order and family). Coenonia, which may not be a dictyostelid, is treated as a genus incertae sedis. Eighty-eight new combinations are made at species and variety level, and Dictyostelium ammophilum is validated.
|
|
