Browsing by Subject "invaasio"

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  • Valtanen, Heli (University of Helsinki, 1997)
  • Kinnunen, Saara (Helsingfors universitet, 2011)
    Plants have always invaded to new locations. The invasion can be seen as a process that has several stages and in every stage different factors can be important. Climate and especially temperature affects on plant distribution and invasion and therefore climate change is predicted to shift plant distributions further north. As a consequence of climate change some harmful weeds, like redroot pigweed (Amaranthus retroflexus L.) and barnyard grass (Echinochloa crus-galli L. Beauv.), from southern regions could also spread to Finland. The aim of this study was to investigate the survival and growth of redroot pigweed and barnyard grass in field conditions in Finland and try to predict their establishment success and possible spread. Weeds were grown with maize in the field and in the greenhouse. Also the effect of climate warming was tested in the greenhouse. Redroot pigweed grew well in the field, despite its late emergence, but barnyard grass germinated and grew poorly. In the greenhouse they both grew well. Competition reduced the vegetative growth of redroot pigweeds and barnyard grass in greenhouse and it reduced seed production both in the field and in the greenhouse. In greenhouse, higher temperature did not cause any effects on the vegetative growth of redroot pigweed or barnyard grass, but redroot pigweed produced more seeds in the warmer temperature. Warmer temperature had no effect on barnyard grasses seed production. These results suggest that redroot pigweed could survive even in present climate conditions in Finland, but the seed production might be less certain. Redroot pigweed would probably benefit from the longer growing season of future. The results of barnyard grass were mixed and nothing certain can be said about its behavior in the future climate.