CHANGES IN SPECIES TRAITS DURING SUCCESSION - A SEARCH FOR PATTERN

Cover data from 13 successional seres starting on bare ground in the w estern part of the Czech Republic sere analysed. The following questio ns were addressed: (1) whether the participation of species with parti cular traits exhibits some trends, and (2) whether primary and seconda ry seres differ from each other in the course of the first 10 yr of su ccession. Primary seres were distinguished from secondary ones a prior i on the basis of absence or presence of (a) organic topsoil, and (b) soil seed bank at the onset of succession. Traits important for the co urse of succession were considered, their relative importance expresse d for each sere and year on the basis of species quantities, and teste d for trends (increase, decrease, unimodal response, no evident trend or absence). The majority of traits considered exhibited some trends i n the course of succession. Participation of C-strategists, phanerophy tes, intensity of lateral spread, presence of VA mycorrhizae, dispersa l by animals and wind, and height of plants significantly increased du ring the first 10 yr of succession, whereas the participation of R-str ategists, therophytes, propagule weight, and capability of forming per sistent seed bank decreased. Participation of S-strategists, geophytes , hemicryptophytes, and all relevant types of pollination did not exhi bit any significant trend. Primary and secondary seres differed from e ach other neither in trends in life-history characteristics of constit uent species nor in their relative importance after the first 10 yr of succession.