10. SAMPLING STRATEGY

For many potential users and uses of the collection, it is important to maximize the number of alleles present within the sample by capturing the greatest proportion of those alleles represented in the field population.  According to Brown and Marshall (1995), at least one copy of 95% of the alleles occurring in the population at frequencies of greater than 0.05 can be achieved by sampling from:

1. 30 randomly chosen individuals in a fully outbreeding sexual species, or
2. 59 randomly chosen individuals in a self fertilizing species.

The reproductive biology of most target species has not been studied, and the capture of rarer alleles would require a markedly increased sample size.  Therefore, collectors are advised to sample from a single population with individuals of the target species in excess of 50 individuals, and to look for populations with larger numbers of plants.  This analysis suggests that, with care, a single population seed sample collected in this way would possess the potential for re-establishment at that site.

As previously mentioned, between 10 and 20 collections across a species range are needed to establish seed zone guidelines and ecotype for a species.  Each collection needs to be of a unique population and contain more than 20,000 seeds.  The first collection of a species should be sent to MSB and subsequent collections should be sent to the Bend Seed Extractory or other domestic cleaning facility, detailed in Section 17. 

In addition, BLM is continually identifying species of priority restoration value needed for native plant materials development.  Teams collecting for BLM should work with their BLM colleagues to ensure that collections are being made of these high priority species.