What have herbaria ever done for us? The role of herbaria in conservation assessments

The world is entering a time of immense environmental upheaval, where experts increasingly are required to provide conservation assessments. A quantitative assessment of trends in range and abundance of flora is costly, requiring extensive field studies over a long period of time. Unfortunately, many plant species are known only from a few chance sightings or a handful of specimens. Specimen-based records provide information on the distribution of taxa through time and space, and a wealth of this knowledge can be found in the taxonomic collections and libraries of herbaria and museums. Conservation assessments are increasingly important, as lists of threatened species often form the primary source of information in the allocation of limited resources for conservation. One of the strengths of using herbarium data is that the results are built on current taxonomic expertise. Such data are derived directly from individual, verifiable records, which represent primary observations. Here we describe a number of techniques that are available for conservation assessments, including Red Listing of species.