What is the standard for determination of Exceptional Species status?
Is it only species that have seeds that exhibit no viability in both desiccation and cold? Or is it a lower bar of reduced viability in both, and if so, how reduced?
There has been discussion around this question, but my current thinking is that it is "seeds that cannot be conserved long-term in conventional seed banks." This includes species without seeds (either because they are not producing seeds, or sufficient seeds, or accessible seeds), recalcitrant seeds, cold sensitive seeds, and short-lived seeds. Of course the terms short-lived and long-lived are not precise, although one definition has been those species with longevities <20% of the maximum longevity of seeds. I don't think that is published at this point. Other definitions I've heard are 10 or 20 years longevity at -20oC.