Ecotypic variation and Seed Transfer Zones
BACKGROUND
While plant species can generally be treated as discrete units that have a unique
ecological role relative to other species, all populations of a broadly distributed
plant species cannot be assumed to be ecologically equivalent. That is, populations
within a species can be grouped into ecotypes that are adapted to fit different
subsets of the total niche occupied by the species. In fact, such ecoptypic
differentiation seems to be the rule: locally sourced plants usually have significantly
higher fitness (greater productivity, higher seed output, etc.) than conspecific plants
derived from off-site [Leimu & Fischer 2008 (will there be references?)].
Furthermore, such local adaptation occurs at a spatial scale that suggests that native
plant species broadly dispersed across the Colorado Plateau are comprised of
distinct ecotypes. The implication for native plant restoration is that the use of
locally sourced plant materials is expected to increase establishment success, and,
importantly, persistence through local climatic cycles. A key question is how many
seed sources need to be developed for the Colorado Plateau for a given native plant
species, and over what geographic extent can each seed source be used, i.e., what is
the "seed transfer zone" for that source. In this section, we will outline multiple
approaches for defining native plant seed transfer zones and provide practical
advice on how to use available information to ensure that the most appropriate
native seed sources are used for a target site.
Methods for Delineating Seed Transfer Zones
 Genecological Approaches including use of molecular marker data; bring
discussion of generality based on mating system here, and in conclusion
 Reciprocal Transplant Studies most direct
 Climate Data Only web seed zone mapper. good start, in fact, and not
surprisingly, multiple recent studies have shown the temp and precip are
consistent drivers of ecolo caveats – eg doesn't include seasonality (or does it) of
precip. Example map. Need to know which species are in which seed zones by
filtering distribution data. Discuss and maybe insert image of monsoonal gradient
to make seasonality point. (Figure 1)
Conclusions
Abundant data make it clear that plant species are comprised of ecologically
differentiated populations, often at a fine scale. –market accommodation –
summarize +/- of each empirical approach. Where to look for information for target
species.
Figure 1. This map of provisional seed transfer zones for the Colorado Plateau is
based on average annual precipitation and maximum mean monthly temperatures.
The map was produced following the strategy of the online Seedzone Mapper tool:
http://www.wwetac.net/index_files/seedzone.shtml. It is important to note that
nearly all restoration species occur in only a fraction of these provisional seed
zones. [Example would make the point easier; have very good distr. data for BOGR2,
ACHY]