Bulletin of the Geobotanical Institute ETH, 68, 29–44 29 Morphological variation of plant populations from differently managed grasslands

1 Morphological traits of plant populations from differently managed grasslands were investigated to test whether genetic differentiation was apparent after 15–30 years of different management. Seeds of three species – Plantago lanceolata, Lotus corniculatus, Campanula rotundifolia – were collected in meadows with contrasting cutting frequency and level of fertilization. Plants were grown from these seeds in a growth room for five weeks, and several morphological traits were measured weekly. 2 In Plantago lanceolata, plants from intensively managed meadows (fertilized, 2–3 cuts per year) produced longer leaves with a lower tissue density than plants from extensively managed meadows (unfertilized, one cut per year). This might enable plants to place their leaf area higher in the canopy in meadows with dense vegetation. The biomass of the flower stalk increased more rapidly in plants from intensively managed meadows, which is interpreted as an adaptation in flowering time to the earlier cutting of the vegetation. 3 Campanula rotundifolia had a lower root/shoot ratio in plants that originate from intensively managed grasslands. This finding is consistent with the hypothesis that in-creased resource allocation to roots is an adaptation to enhance nutrient acquisition in habitats with low nutrient availability. 4 Within-population variation in morphological traits did not differ consistently be-tween populations from extensive and those from intensive meadows. Thus, our results do not show that genetic variability is reduced by intensive management. 5 This study indicates that genetic adaptation may develop within the relatively short period of 15–30 years as a consequence of changes in management practices