Species Numbers of Vascular Plants in Relation to Area, Isolation and Age of Ponds in Denmark

Partial correlation analysis indicate that area affects both the space for vegetational development and the immigration rate. Recently created or restored ponds display species numbers much higher than predicted by area. The influence of isolation is discussed in terms of a rescue-effect among close ponds. The need for better estimates of isolation within archipelagoes of small biotopes is stressed, and some components of a more precise estimate are proposed.