Flowchart

Taxonomy:

• Nomenclature (taxon name, authority, synonyms etc.).
• Recent taxonomic changes, any current taxonomic doubts or debates about the validity or identity of the species, or issues of synonymy.
• Note any subspecific taxa.
• Crop(s) the species is related to (common and scientific names) and information on the degree of relatedness between the wild relative and the crop (where known) using the Gene Pool concept (Harlan and de Wet 1971) or Taxon Group concept (Maxted et al. 2006).

Distribution and occurrence:

• Summary of the current information available regarding the geographic range of the species.
• Countries of occurrence (and sub-national unit(s), where applicable) recorded using built-in descriptors in IUCN’s Species Information Service (SIS).
• Extent of occurrence and/or area of occupancy (See the Box on ‘Geographic range measurements used in criterion B’).
• A map showing the distribution of the species.

Population:

• Summary of the size and trend information available (i.e. increasing, decreasing or stable) of the overall population of the species. If the population is severely fragmented, this is also recorded.
• Information about sizes and trends of subpopulations or populations of subspecific taxa, or trends in particular areas of the species’ range can also be included when available.
• Where no quantitative information on population sizes or trends is available, an indication of whether the species is common, abundant, or rare etc. should be noted where possible. If there really is no information about the population, this should be noted.

Habitats and ecology:

• A summary account of the suitable habitats and ecological requirements of the species, highlighting any potential traits that may be of interest for crop improvement (e.g. drought and salt tolerance).
• Comments on the area, extent and/or quality of habitat. In particular, whether the habitat is thought to be stable or declining.
• The habitat(s) in which the species occurs, documented using IUCN’s Habitats Classification Scheme.

Use and trade:

• A summary account of the information available for any utilization and/or trade of the taxon (local, national and international trade).
• A note of any known or potential uses of the species as a gene donor for crop improvement.

Threats:

• Major threats that have affected the species in the past, those that are affecting the species now, or those that are likely to affect the species in the future.
• The main reason for the threat, the scale of the threat and the stress placed on the species are also recorded where the information is available.
• Threats are documented using IUCN’s Threats Classification Scheme.

Conservation:

• Any conservation actions currently in place and any realistic actions needed to mitigate threats causing declines, including information on both in situ and ex situ conservation measures.
• Conservation actions are documented using IUCN’s Conservation Actions Classification Scheme.

Source: adapted from Kell et al. (2012)

Application of the IUCN Red List Categories and Criteria (IUCN 2012a) requires the use of ‘the best available evidence’. For plants, herbarium and genebank collections usually provide the only source of information for the threat assessment and must therefore qualify as ‘best available evidence’ (Willis et al. 2003), even though they can provide little help in estimating population changes over time. Schatz et al. (2000) and Golding (2002) consider that these data are sufficiently reliable to enable conservation decisions. However, information provided by specimens can result in inconsistent Red List classifications because of the uncertainty associated with population and distribution parameters that arise from the decision rules of the IUCN Red List (IUCN 1994, 2012a).

Often, information used in Red List assessments is interpreted from locality and habitat information contained on specimen labels and inferences and projections are made regarding distribution ranges, scarcity and declines of species. When limited information is available, data often need to be extrapolated in order to make informed estimates, inferences and projections (Golding 2004). On the other hand—while collections made over the last 50 to 60 years usually provide data regarding scientific name, locality, habitat, ecology, date of collection, collector name and collector number—the historical specimens (before or from early 20th century) may only contain few hand written details of the plant name, collector and locality and therefore may be of limited value to conservation assessments. MacDougall et al. (1998) refer to herbarium specimen sheets as a qualitative rather than quantitative data source. Locality coordinate data acquired from herbarium specimen data will often only provide an approximation of species distribution (Willis et al. 2003).

Therefore, the use of specimen passport information from a single population sample should be regarded as provisional because it can result in an inaccurate assignment of Red List statuses of poorly known species, and consequently, influence conservation recommendations (Golding 2004). However, despite the uncertainty, herbarium specimens can be a good start when assessing species extinction risk.