ECOTYPIC VARIATION IN RELATION TO MAN-MADE HABITATS IN CAPSELLA - FIELD AND TRAMPLING AREA

Intraspecific differentiation of the worldwide distributed weed Capsel la bursa-pastoris has been studied on a local scale. Differentiation p atterns are clearly correlated to man made habitats (arable field as o pposed to trampling area). a) The seeds of the arable field population seemed to increase germination when covered with soil in contrast to the trampling area population. b) Arable field - early flowering with low variability; greater plant height and more stem branches; larger s eed pots; higher seed output. c) Trampling area - late flowering, well developed rosettes;high phenotypic plasticity in begin of flowering, plant height, branching number and fruit dimensions. d) Nutrient suppl y increased rosette diameter, plant height, number of stem branches, f ruit dimensions and seed number within the arable field population, bu r not the trampling area plants; instead, numbers of rosette leaves an d branching number. The reaction norm between the populations was diff erent for some fitness parameters: nutrient supply decreased phenotypi c variability in rosette diameter within the arable field population w hereas in the trampling area population it decreased phenotypic variab ility in plant height, branching number and fruit dimensions. Both pop ulations differed significantly in all measured parameters. The relati on of characters to habitat is discussed.