XVI International Botanical Congess

We used two data sets on long term changes in vascular plant compositions in Finnish lakes to study theories of biogeography. First, we tested relationships between lake area and species immigration, extinction and turnover rates. We found that extinction rate was negatively related to shoreline length. We conclude that shoreline length is a better measure of suitable habitat to water plants than the lake area, and because correlation between turnover rate and area were insignificant, also small lakes can be valuable for conservation. Another data set was collected in lakes throughout Finland. We used these data to study if plant community persistence is related to latitude. A theory predicts that northern communities are unstable. However, we found that turnover rate was inversely related to latitude.