VARIATION IN STAGE STRUCTURE AND FITNESS TRAITS BETWEEN ROAD VERGE AND MEADOW POPULATIONS OF COLCHICUM AUTUMNALE (LILIACEAE): EFFECTS OF HABITAT QUALITY

摘要

The frequency distribution and density of three life stages as well as fitness components of the perennial plant Colchicum autumnale growing in the unmanaged road verges and in the extensive mown and grazed meadows in the Sudeten Mts. were studied. Furthermore, investigated were the effects of population size and plant size (measured as number of flowers) on reproductive success and explored if variation in reproductive and vegetative traits of adults could be associated with soil characteristics. The t-test indicated that proportions of subadults and reproductive adults were significantly lower in verge than in meadow populations, and of vegetative adults significantly higher. The plant density of reproductive adults and the reproductive adults to all adults ratio were significantly lower in verge populations compared to meadow populations. Although habitat type accounted for significant variation in stage structure, no significant difference was found between vegetative and reproductive traits in adult plants, except for the number of flowers. In verge populations the number of flowers was significantly lower as compared to meadow populations. The traits related to reproduction were not significantly influenced by population size. However, the proportion of flowers setting fruit decreased significantly with increasing number of flowers. The stepwise multiple regression revealed significant relationships between soil characteristics and number of fruits per plant, fruit set, number seeds per plant and number of leaves in vegetative adults. The results suggest that the creation of the low and relatively open vegetation cover could increase the chance of persistence of C. autumnale living in verge habitats by promoting of seed germination, seedling establishment and flowering, and they also show that the reproductive success and vegetative components of fitness are most likely influenced by habitat quality.