No relationship between range size and germination niche width in the UK herbaceous flora

1. It is widely assumed that species with broad niches will be commoner (have larger ranges) than species with narrow niches, but attempts to demonstrate this in plants and animals have generally been unsuccessful. 2. We used seasonal seedling emergence data to define the width of one important niche axis for 175 UK herbaceous species. We then compared niche width with UK range, using species as independent data points and also phylogenetically independent contrasts. 3. We found no evidence of any relationship between niche width and range. Possible reasons for this are: (i) mature plant traits are more important than seedling emergence in determining plant ranges; and (ii) ranges of most plants are strongly dispersal-limited.