| 1. |
- Cousins, Sara, et al.
(författare)
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I nattviolens hage
- 2008
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Ingår i: Olsson, R. (red), Mångfaldsmarker. - Uppsala : Centrum för biologisk mångfald. - 9789189232297 ; , s. 9-28
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- I en svensk naturbetesmark kan man hitta över 40 växtarter inom en enda kvadratmeter. Det är världsrekord. En stor del av de arter som finns i betesmarkerna förekommer inte i andra naturtyper. Idag återstår inte mer än en tiondel av den areal naturbetesmarker som fanns i Sverige för drygt 100 år sedan. Igenväxningen hotar inte bara en lång rad arter. Också stora kulturhistoriska värden och vårt vackra, variationsrika odlingslandskap står på spel. Fortsatt hävd förutsätter att det finns en levande landsbygd med bärkraftiga jordbruksföretag.
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| 2. |
- Emanuelsson, Urban, et al.
(författare)
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Naturbetesmarker i Sverige och Europa
- 2008
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Ingår i: Olsson, R. (red), Mångfaldsmarker. - Uppsala : Centrum för biologisk mångfald. - 9789189232297 ; , s. 29-37
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Emanuelsson, Urban, et al.
(författare)
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Varifrån kommer naturbetesmarkernas arter?
- 2008
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Ingår i: Olsson, R. (red), Mångfaldsmarker. - Uppsala : Centrum för biologisk mångfald. - 9789189232297 ; , s. 47-52
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Jönsson, K. Ingemar, 1959-
(författare)
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Radiation tolerance in tardigrades : evidence and implications
- 2008
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Ingår i: Comparative Biochemistry and Physiology A. - 1095-6433 .- 1531-4332. ; 151:Suppl. 1, s. S33-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Tardigrades belong to the most desiccation-tolerant animals on Earth, and are able to lose practically all water in their cells without dying. Recent investigations have also confirmed a seminal study from 1964 showing that tardigrades have an extraordinary tolerance also to ionizing radiation. The biochemical and physiological mechanisms behind these two tolerance phenomena, and the possible functional link between them, is currently not understood. However, the finding that desiccated and non-desiccated tardigrades show similar tolerances to ionizing radiation suggests that radiation tolerance in these animals is not a physical function of the dry state. Rather, both mechanisms preventing damage and mechanisms repairing damage to cell components are likely to be involved. The possible involvement of DNA repair mechanisms in tolerances of anhydrobiotic animals make them of special interest for understanding naturally evolved adaptations for coping with environmental agents inducing damage to DNA. I will summarize our current knowledge about radiation tolerance in tardigrades and other anhydrobiotic animals, discuss some of its implications for our understanding of desiccation tolerance, and also present some recent data on radiation tolerance in tardigrade embryos.
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| 5. |
- Jönsson, K. Ingemar, 1959-, et al.
(författare)
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Tardigrades survive exposure to space in low earth orbit
- 2008
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Ingår i: Current Biology. - 0960-9822 .- 1879-0445. ; 18:17, s. R729-R731
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Tidskriftsartikel (refereegranskat)abstract
- Vacuum (imposing extreme dehydration) and solar/galactic cosmic radiation prevent survival of most organisms in space . Only anhydrobiotic organisms, which have evolved adaptations to survive more or less complete desiccation, have a potential to survive space vacuum, and few organisms can stand the unfiltered solar radiation in space. Tardigrades, commonly known as water-bears, are among the most desiccation and radiation-tolerant animals and have been shown to survive extreme levels of ionizing radiation. Here, we show that tardigrades are also able to survive space vacuum without loss in survival, and that some specimens even recovered after combined exposure to space vacuum and solar radiation. These results add the first animal to the exclusive and short list of organisms that have survived such exposure.
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| 6. |
- Magntorn, Ola, 1964-
(författare)
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Sötvattenmärlans hemlighet
- 2008
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Ingår i: Lytsy, A. (red.), Man måste tycka om dem!. - Stockholm : Skolporten. - 9789197623629 ; , s. 170-179
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Oweson, Carolina, et al.
(författare)
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A comparative study on the influence of manganese on the bactericidal response of marine invertebrates
- 2009
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Ingår i: Fish and Shellfish Immunology. - 1050-4648 .- 1095-9947. ; 27:3, s. 500-507
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Tidskriftsartikel (refereegranskat)abstract
- Manganese, Mn, is a naturally abundant metal in marine sediments. During hypoxic conditions the metal converts into a bioavailable state and can reach levels that have been shown immunotoxic to the crustacean Nephrops norvegicus. For this species it has previously been shown that exposure to 15 mg L(-1) of Mn decreased the number of circulating haemocytes while it for the echinoderm Asterias rubens increased the number of coelomocytes. Here, we compared if five days of exposure to the same concentration of Mn affects the bactericidal capacity of these two species and the mollusc Mytilus edulis when inoculated with the bacterium Vibrio parahaemolyticus. Viable counts of the bacteria were investigated at a time-course post-injection in the blood and the digestive glands of Mn-exposed and un-exposed (controls) animals. Accumulation of Mn was also analyzed in these tissues. When exposed to Mn the haemocyte numbers were significantly reduced in M. edulis and it was shown that the bactericidal capacity was impaired in the mussels as well as in N. norvegicus. This was most obvious in the digestive glands. These two species also showed the highest accumulation of the metal. In A. rubens the bactericidal capacity was not affected and the metal concentration was similar to the exposure concentration. After a recovery period of three days the concentration of Mn was significantly reduced in all three species. However, in M. edulis and N. norvegicus it was still double that of A. rubens which could explain the remaining bactericidal suppression observed in N. norvegicus. This study pointed out that exposure to such Mn-levels that are realistic to find in nature could have effects on the whole organism level, in terms of susceptibility to infections. The effect seemed associated to the accumulated concentration of Mn which differed on species level.
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| 8. |
- Elmberg, Johan, et al.
(författare)
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Within-season sequential density dependence regulates breeding success in mallards Anas platyrhynchos
- 2005
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Ingår i: Oikos. - 0030-1299 .- 1600-0706. ; 108, s. 582-590
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Tidskriftsartikel (refereegranskat)abstract
- Density dependence in vital rates is a key issue in population ecology but remains largely unexplored experimentally. We studied breeding success, lake use, and prey availability in wild mallards Anas platyrhynchos on small nemoral lakes in a replicated, two-year cross-over experiment in which pair density was increased. The number of wild mallards that settled on lakes prior to introductions of extra pairs did not differ between control and introduction years. Introductions led to a lake-level reduction in the number of broods observed. However, the number of stage 2/ (almost fledged) ducklings did not differ between treatments, nor did lake utilization by nonbreeding adults, broods and ducklings. Prey resource availability differed greatly among lakes, but it did not correlate with breeding success. Partialling out the possible effect of food competition from wild adult nonbreeding mallards did not change this conclusion. Our study demonstrates sequential density dependence in breeding success; introductions caused a decrease in brood number, but despite fewer broods a similar number of nearly fledged ducklings were produced. We suggest that predation and/or lake change of broods soon after hatching created these patterns. We conclude that using a single and late measure of breeding success such as fledged birds can mask regulatory processes. Implications of density dependence and its relation to individual reproductive success are understood better if breeding success is decomposed into nest success, duckling survival and fledgling survival.
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| 9. |
- Faurby, Sören, et al.
(författare)
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Variation in anhydrobiotic survival of two eutardigrade morphospecies : a story of cryptic species and their dispersal
- 2008
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Ingår i: Journal of Zoology. - 0952-8369 .- 1469-7998. ; 275:2, s. 139-145
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Tidskriftsartikel (refereegranskat)abstract
- Studies of geographic variation in anhydrobiotic tolerance may increase our understanding of the population dynamics of terrestrial meiofauna and the relative importance of local adaptation and microhabitat niche separation. Although anhydrobiosis in tardigrades has been studied extensively, few studies have dealt with intraspecific variation in survival and none of these included genetic data to validate the intraspecific nature of the comparisons. Such data are necessary when working with meiofauna as cryptic species are common. We analysed the anhydrobiotic survival and genetic variation in cytochrome oxidase subunit I of two eutardigrades (Richtersius coronifer and Ramazzottius oberhaeuseri) from Italy and Sweden to detect possible local adaptation. Survival was analysed as a multidimensional contingency table and showed that anhydrobiotic survival was higher in Sweden for Ra. oberhaeuseri whereas no significant geographic variation was found for Ri. coronifer. Our genetic analysis indicated the coexistence of two cryptic species of Ra. oberhaeuseri in Italy, only one of which was found in Sweden. It could not be determined whether the variation in Ramazzottius is intra- or interspecific due to the presence of these cryptic species. We suggest that geographic variation in anhydrobiotic survival may be a general phenomenon in tardigrades but further research is necessary to determine the degree of intraspecific variation. The genetic analysis showed indications of long-term isolation of the individual populations of Ri. coronifer but recent dispersal in one of the cryptic species of Ramazzottius. We found higher survival in Ra. oberhaeuseri than in Ri. coronifer. These results indicate a possible coupling between anhydrobiotic survival and dispersal rate.
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| 10. |
- Jönsson, K. Ingemar, 1959-, et al.
(författare)
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Sexual patterns of prebreeding energy reserves in the common frog Rana temporaria along a latitudinal gradient
- 2009
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Ingår i: Ecography. - : Wiley-Blackwell. - 0906-7590 .- 1600-0587. ; 32:5, s. 831-839
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Tidskriftsartikel (refereegranskat)abstract
- The ability to store energy is an important life history trait for organisms facing long periods without energy income, and in particular for capital breeders such as temperate zone amphibians, which rely on stored energy during reproduction. However, large scale comparative studies of energy stores in populations with different environmental constraints on energy allocation are scarce. We investigated energy storage patterns in spring (after hibernation and before reproduction) in eight common frog (Rana temporaria) populations exposed to different environmental conditions along a 1600 km latitudinal gradient across Scandinavia (range of annual activity period 3-7 months). Analyses of lean body weight (eviscerated body mass), weight of fat bodies, liver weight, and liver fat content, showed that (i) post-hibernation/pre-breeding energy stores increased with increasing latitude in both sexes, (ii) males generally had larger energy reserves than females and (iii) the difference in energy stores between sexes decreased towards the north. Larger energy reserves towards the north can serve as a buffer against less predictable and/or less benign weather conditions during the short activity period, and may also represent a risk-averse tactic connected with a more pronounced iteroparous life history. In females, the continuous and overlapping vitellogenic activity in the north may also demand more reserves in early spring. The general sexual difference could be a consequence of the fact that, at the time of our sampling, females had already invested their energy into reproduction in the given year (i.e. their eggs were already ovulated), while the males' main reproductive activities (e.g. calling, mate searching, sexual competition) occurred later in the season.
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