DISTRIBUTIONAL RANGE SIZE OF WEEDY PLANT SPECIES IS CORRELATED TO GERMINATION PATTERNS

Abstract

For plant species adapted to disturbances, the germination niche breadth (the time span within a year during which the species is able to germinate) may be a key in understanding the variability of range sizes across species. Species that are able to germinate throughout the year should be able to use more disturbances and build up large local populations. As population size is correlated to distribution, one would expect a correlation between the temporal germination pattern and distributional range sizes. For a test of this hypotheses, we used germination patterns and local abundance data from 31 weedy plant species from an abandoned field in eastern Germany. In cross-species and phylogenetically controlled analyses, the germination niche breadth was correlated to range size on the national, as well as the continental scale. However, significant correlations between ger- mination niche breadth and abundance, as well as abundance and range size, appeared only in a phylogenetically controlled analysis. In multiple regression analyses, the germination niche breadth turned out to be the most important predictor of distributional range sizes for our subset of weedy species. These results suggest that, for weedy species, the ger- mination niche breadth influences distributional range size. However, the detailed process behind these relationships remains elusive. Nevertheless, the regeneration niche of plants may be a useful concept for exploring macroecological relationships in plants.