Dynamics in submersed Charophyta vegetation in three Swedish lakes

• Main Author: Thureborn, Olle
• Format: Bachelor Thesis
• Language: English
• Published: Södertörns högskola, Institutionen för livsvetenskaper 2011
• Subjects: Chara aspera; Chara intermedia
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-15366

The vegetation dynamics of submersed Charophyta vegetation were studied in three shallow lakes, located around 25 km southeast of Gävle, close to theBaltic Sea. The samples were taken with a plastic tube used as a homemade sediment core sampler. The samples were then divided into a lower, middle and an upper layer so that temporal patterns inferred from sedimentation order could be studied. For making the statistical analyzes the program R version 2.12.1 for windows was used. The aims of this study were to describe how the vegetation dynamic changes over time in the three different lakes selected and develop methods on how to use the spore bank to make temporal surveys. Altogether three species were found at the study sites, Chara intermedia, Chara aspera and Chara tomentosa. The results showed that Chara in general behave differently between the communities, i.e. the lakes have different vegetation dynamics. Directional changes were shown for C. aspera and C. intermedia whereas C. tomentosa showed clear signs of patch dynamics. The results are discussed from different viewpoints, such as eutrophication, salinity variation, intraspecific competition and founder or dominance- controlled communities. Stoneworts are sensitive to eutrophication, and many of the Swedish species are today red listed. Understanding the vegetation dynamics of stonewort species are therefore of great relevance. This study show that it is possible to make a temporal vegetation dynamics survey using a spore bank. Vegetationsdynamiken hos Charophytavegetation har studerats i tre grunda sjöar. De studerade sjöarna ligger ungefär 25 km sydost om Gävle, nära Östersjön. Sedimentproverna togs upp med hjälp av ett plaströr som fungerade som en sedimentprovtagare. Varje prov skivades sedan upp i tre skikt, undre, mellan och övre för att kunna studera vegetationsförändringar över tid. För de statistiska analyserna användes programmet R version 2.12.1 för windows. Syftet med denna studie var att beskriva hur vegetationsdynamiken förändras över tid ...