In the Chicken Creek catchment, constructed in 2005, we studied the colonising plant species, their possible entry pathways via soil substrate and wind as well as the vegetation development. The surveys enabled us to understand the population dynamics of the dominant early colonisers. Peak abundances of some species occurred early, e.g. for C. canadensis in 2007. Afterwards this annual decreased significantly. While population increases are well comprehensible according to our data and the existing theoretical concepts, such early decreases are not. Our data indicate that life-processes of the dominating species C. canadensis do not match with its performance over time: In contrast to the decreasing Conyza population, the life-processes that drive succession gave reason to expect a further increase in importance. Thus we suppose other processes to play an important role, namely decreasing nutrient availability after catchment construction at first. We will introduce these ideas.