[tdwg-tag] taxonomic rank terms

Hi Roger and others, I know that the tdwg ontology effort is currently in a state of flux, but I have a specific question that perhaps someone can answer here. What is or will be the fate of the vocabulary of rank terms at http://rs.tdwg.org/ontology/voc/TaxonRank? The disclaimer at the top of the page includes that the http URIs of 'key concepts' will be maintained, but are these rank terms going to be preserved? If so, will their URI's remain stable? Are there plans to prune any out?

Thanks,

Peter Midford