Effekter av urbanisering på grönalgen trädgröna i Linköpings stad med omnejd. : Biologiundervisning i närmiljön

Sammanfattning: Urbanization has for a long time been a threat to our biodiversity. Epiphytic organisms such as lichens have been negative affected by traffic pollution and the new urban environment surrounding their old habitat (van Her 2001). Another epiphytic organism is the green algae Desmococcus olivaceus. Unlike lichens the green algae is favoured by polluted areas. The aim of this study was to investigate if time in urban environments affected the cover of the green algae on old oaks. 91 oaks were investigated in urban and rural environments in and around Linköping city, Sweden. Data were collected on cover from green algae, lichens and mosses and analysed with regard to the time in urban environment. There were no correlation between time in urban environments and the cover of the green algae, however, the presence of green algae on an oak increased by the time in urban environment. The results also indicated that green algae were distributed on the northwest side of the trunk, whereas lichens were distributed on the northeast side. This could be due to competition between the epiphytic groups. The study also contains findings of four exercises of outdoor education in the field of ecology for high school students.