| 1. |
- Blicharska, Malgorzata, et al.
(författare)
-
Old Trees: Cultural Value
- 2013
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 339, s. 904-
-
Annan publikation (övrigt vetenskapligt/konstnärligt)
|
|
| 2. |
|
|
| 3. |
- Renes, Sophia Elise, et al.
(författare)
-
Disturbance history can increase functional stability in the face of both repeated disturbances of the same type and novel disturbances - dataset
- 2020
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1
-
Annan publikationabstract
- Climate change is expected to increase the incidences of extremes in environmental conditions. To investigate how repeated disturbances affect microbial ecosystem resistance, natural lake bacterioplankton communities were subjected to repeated temperature disturbances of two intensities (25 °C and 35 °C), and subsequently to an acidification event. We measured functional parameters (bacterial production, abundance, extracellular enzyme activities) and community composition parameters (richness, evenness, niche width) and found that, compared to undisturbed control communities, the 35 °C treatment was strongly affected in all parameters, while the 25 °C treatment did not significantly differ from the control. Interestingly, exposure to multiple temperature disturbances caused gradually increasing stability in the 35 °C treatment in some parameters, while others parameters showed the opposite, indicating that the choice of parameters can strongly affect the outcome of a study. The acidification event did not lead to stronger changes in community structure, but functional resistance of bacterial production towards acidification in the 35 °C treatments increased. This indicates that functional resistance in response to a novel disturbance can be increased by previous exposure to another disturbance, suggesting similarity in stress tolerance mechanisms for both disturbances. These results highlight the need for understanding function- and disturbance-specific responses, since general responses are likely to be unpredictable.
|
|
| 4. |
- Söderquist, Linus, et al.
(författare)
-
Genetic structure and diversity of the declining orchid Gymnadenia conopsea in Scandinavia: implications for conservation and management
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Understanding how historical versus contemporary processes shape population genetic structure and variation is important to design effective management actions for threatened species. To unravel population structure, connectivity, and genetic variation in the declining Gymnadenia conopsea, we genotyped 1,834 SNPs in 1,120 individuals in 110 populations, in three different habitats (fen, meadow, coastal) across Scandinavia. We further tested if genetic diversity increases with census population size, and is higher in core habitats (fen and meadow) than in marginal, coastal habitats. We identified three main genetic clusters and pronounced isolation by distance, consistent with two independent colonization routes after last glacial maximum, followed by admixture. Estimates of effective migration using EEMS indicated reduced gene flow between coastal and inland populations, suggesting that the complex topography of the fjord landscape constitutes a dispersal barrier. Genetic diversity increased with census population size. The highest genetic diversity was found in core habitats, in meadows in southern Sweden and in inland fens along the Scandes mountains, while the lowest genetic diversity was found on the Atlantic coast and in a few populations scattered across Scandinavia. Genetic diversity did not vary significantly among habitat types. In conclusion, current genetic structure suggests a strong legacy of historical events, and the high genetic diversity documented in the main Scandinavian range indicates that both current viability and future adaptation potential is high. To maintain genetic diversity and connectivity, it is particularly important to preserve southern meadow populations, which depend on traditional land use, along with central fen populations.
|
|
| 5. |
- Söderquist, Linus, et al.
(författare)
-
Population viability of the orchid Gymnadenia conopsea increases with population size but is not related to genetic diversity
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Population size is a main indicator of conservation value, thought to indicate both current and long-term population viability. However, few studies have directly examined the links between the size and the genetic and demographic properties of populations using metrics that integrate effects across the whole life cycle. In this study, we combine six years of demographic data with SNP-based estimates of genetic diversity from 18 Swedish populations of the orchid Gymnadenia conopsea, a species that is becoming increasingly rare in Europe. We investigated how population growth rate varied among populations and years, and used LTRE analysis to evaluate how underlying vital rates contribute to the variation. We examined if stochastic growth rate increased with population size and genetic diversity. For each population, we estimated the probability of quasi-extinction and of a 90% decrease in population size, within the next 30 years. Deterministic growth rate varied among populations and years, and the LTRE decomposition suggested that variation in both fecundity, and survival and growth of adults, contributed to this variation. Estimates of stochastic growth rate indicated that ten populations are declining, seven increasing, and one population approximately stable. Stochastic growth rate increased with population size, mainly due to higher survival in larger populations, but was not related to genetic diversity. One third of the populations were predicted to go extinct and eight populations to undergo a 90% decrease in population size in the coming 30 years. The results suggest that ongoing declines are not due to genetic erosion. Low survival in small populations most likely reflects a positive association between local environmental conditions and population size. More generally, the results suggest that demographic metrics can be more informative than genetic metrics, regarding conservation priority.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Sassenhagen, Ingrid
(författare)
-
Ciliate grazing on the bloom-forming microalga Gonyostomum semen
- 2023
-
Annan publikationabstract
- The freshwater raphidophyte Gonyostomum semen forms extensive summer blooms in northern European humic lakes. The development of these blooms might be facilitated by a lack of natural top-down control, as few zooplankton species are able to prey on these large algal cells (up to 100µm) that expel trichocysts upon physical stress. In this study, we describe a small ciliate species (<17µm) that preys on G. semen by damaging the cell membrane until cytoplasm and organelles spill out. Sequencing of clonal cultures of the ciliate tentatively identified it as the prostomatid species Urotricha pseudofurcata. Grazing experiments illustrated that feeding by U. cf. pseudofurcata can significantly reduce cell concentrations of the microalga. However, differences in cell size and growth rate between two investigated ciliate strains resulted in noticeably different grazing pressure. Environmental sequencing data from five different lakes supported potential interactions between the two species. Urotricha cf. pseudofurcata might, thus, play an important role in aquatic ecosystems that are regularly dominated by G. semen, reducing the abundance of this bloom-forming microalga and enabling transfer of organic carbon to higher trophic levels.
|
|
| 9. |
|
|
| 10. |
|
|
