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Träfflista för sökning "WFRF:(Jakobsson Sven 1951 ) "

Search: WFRF:(Jakobsson Sven 1951 )

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1.
  • Jonsson, B. G., et al. (author)
  • Skogspolitiken hotar biologiska mångfalden
  • 2008
  • In: Dagens Nyheter. ; 14 april
  • Journal article (other academic/artistic)abstract
    • Ledande svenska forskare varnar för att det nationella naturarvet äventyras: Vi skäms över våra beslutsfattares likgiltighet för miljön. Den svenska skogen har förvandlats till en jättelik odlingsyta. Där förr otaliga arter levde samman i harmoni dominerar numera helt gran, tall och inplanterade främmande trädslag. Denna skogsodling utgör ett hot mot den biologiska mångfalden vilket strider mot riksdagens miljökvalitetsmål. Den svenska skogspolitiken vilar officiellt på att produktion av skogsråvara och miljö är likvärdiga mål. Men i praktiken har produktionen satts i första rummet. Bortåt 2 000 skogslevande arters överlevnad hotas på grund av den förda politiken. Vi är djupt oroade och skäms över att det rika Sverige inte arbetar effektivt för att nå nationella och internationella miljömål. Det skriver 14 ledande forskare i bland annat växtekologi, ekologisk zoologi och botanik.
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2.
  • Hedlund, Johanna, et al. (author)
  • Increase in protandry over time in a long-distance migratory bird
  • 2022
  • In: Ecology and Evolution. - : Wiley. - 2045-7758. ; 12:7
  • Journal article (peer-reviewed)abstract
    • Protandry is a widespread life-history phenomenon describing how males precede females at the site or state of reproduction. In migratory birds, protandry has an important influence on individual fitness, the migratory syndrome, and phenological response to climate change. Despite its significance, accurate analyses on the dynamics of protandry using data sets collected at the breeding site, are lacking. Basing our study on records collected during two time periods, 1979 to 1988 and 2006 to 2016, we aim to investigate protandry dynamics over 38 years in a breeding population of willow warblers (Phylloscopus trochilus). Change in the timing of arrival was analyzed in males and females, and protandry (number of days between male and female arrival) was investigated both at population level and within breeding pairs. Our results show advancement in the arrival time at the breeding site in both sexes, but male arrival has advanced to a greater extent, leading to an increase in protandry both at the population level and within breeding pairs. We did not observe any change in sex ratio that could explain the protandry increase, but pronounced temperature change has occurred and been reported in the breeding area and along the migratory route. Typically, natural selection opposes too early arrival in males, but given warmer springs, this counteracting force may be relaxing, enabling an increase in protandry. We discuss whether our results suggest that climate change has induced sex-specific effects, if these could be evolutionary and whether the timing of important life-history stages such as arrival at the breeding site may change at different rates in males and females following environmental shifts.
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4.
  • Jakobsson, Sven, 1951- (author)
  • Tovetorps Forskningsstation
  • 2011
  • In: Sörmlandsbygden 2012. - Nyköping : Österbergs & Sörmlandstryck. ; , s. 49-66
  • Book chapter (pop. science, debate, etc.)
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5.
  • Vallin, Adrian, et al. (author)
  • Constant eyespot display as a primary defense – survival of male and female emperor moths when attacked by blue tits
  • 2010
  • In: The Journal of Research on the Lepidoptera. - : ISSN 0022-4324 (prINt) tHe lepIDopterA reSeArCH FoUNDAtIoN. - 0022-4324 .- 2156-5457. ; 43, s. 9-17
  • Journal article (peer-reviewed)abstract
    • Large conspicuous eyespots, commonly found on the wings of butterflies and moths, have been shown to thwart attacks from predators. Previous experiments have focused on lepidopteran species that expose eyespots only when harassed by a predator. In contrast, we investigate the potential efficiency of the constantly exposed eyespots of emperor moths thus constituting a primary defense. We staged experiments between blue tits and moths having either intact or painted over eyespots. Moths with eyespots were killed as often as moths without eyespots and were, additionally, approached earlier by the birds suggesting that birds were not intimidated by their eyespots. Female moths weighed three times more than males and were less often eaten, suggesting that their large size intimidated the birds. We suggest that the constant eyespot display of the emperor moth may be associated with a cost, because potential predators seem to be attracted rather than intimidated by the display.
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