THE EFFECT OF BEDROCK TYPE, TEMPERATURE AND MOISTURE ON SPECIES RICHNESS OF PYRENEAN SCOTS PINE (PINUS-SYLVESTRIS L) FORESTS

The relationship between environmental parameters (bedrock type, tempe rature and moisture index) and understorey species richness was studie d from a large phytosociological data base on Pyrenean Scots pine (Pin us sylvestris L.) forests. Generalized linear models were used to test this relationship. Total species richness and species richness of the different life forms were considered. The results suggest different p atterns for the different life forms, and that the richest forest was on the calcareous bedrock of north-facing slopes at low altitudes.