Environmental variation is a crucial driver of ecological pattern, and spatial layers representing this variation are key to understanding and predicting important ecosystem distributions and processes. A national, standardised collection of different environmental gradients has the potential to support a variety of large-scale research questions, but to date these data sets have been limited and difficult to obtain.
There are many examples in the literature of a positive correlation between the distribution of a species and its local abundance, i.e., widely occurring species tend to be more abundant locally when they do occur. Such relations have been documented over a wide range of taxa and spatial scales. There are five major hypotheses seeking to explain the relation: Random placement, Sampling error, Niche width, Demography, and Metapopulation dynamics. However, there is little evidence to distinguish between them, especially for plants.