[PCA] Isoaltion Distances

[Eric Mader]

Hi Clara,

I'm not sure if anyone has weighed in with a response, but here's a few
thoughts and resources that might be helpful:

First, like practically all native seed production issues, there is a
spectacular lack of research/development/technology transfer that has been
conducted on crop isolation differences. Hence for most of these species,
recommended isolation distances are simply guesswork.

Second, if you do want to look into the limited peer reviewed research out
there, switchgrass and sunflower are two native plants that have been
studied for gene flow between cultivated/hybrid varieties, and wild plants.
That info might provide you with a reasonable estimate of optimal isolation
distances that you could apply to all of your grasses and forbs
accordingly.

Third, crop isolation isn't simply a matter of distance. Vegetable seed
producers will sometimes try to isolate crops by taking advantage of
physical landscape features such as shelterbelts, forest patches, or
treelines, etc. to reduce pollinator movement between separate crop fields.

Fourth, pollen contamination can be confounded by local honey bees which
travel huge distances (relative to native pollinators) and can facilitate
pollen transfer through stray pollen grains inside the hive. In research on
genetically modified alfalfa, honey bee foragers leaving hives were found
to sometimes carry viable pollen accidentally picked up inside the hive.
This means honey bee forager X might pick up pollen while visiting a patch
of flowers two miles to the east, and accidentally drop some of those
pollen grains inside the hive or brush up against other bees inside the
hive, resulting in pollen grains being picked up by forager Y on her way
out to visit a patch of flowers two miles to the west.

Some of the basics of managing isolation distances for vegetable crops
might be useful to you, and I'd encourage you to check out the following
document here:

http://www.xerces.org/wp-content/uploads/2013/06/PollinatorManagementForOrganicSeedProducers.pdf

For what it's worth I've only see clear example of hybridization in seed
crops that were planted side by side, and I haven't even seen that very
often (mostly with a couple of western milkweed species). In other settings
I've managed large fields of various Silphiums, Echinaceas, etc., side by
side and never observed obvious intermediate types among the resulting
seed. Grasses are of course a little trickier to observe intermediate forms
potential hybrids in. Interestingly, sedges were a group that I always
suspected were prone to hybridization--adjacent seed production beds
sometimes resulted in seedling plants that defied existing taxonomic keys.

Good luck,

Eric

---
Eric Lee-Mӓder
- Pollinator Program Co-Director, The Xerces Society for Invertebrate
Conservation
- USDA-NRCS Technical Service Provider, TSP-10-6572


Salish Sea Regional Office, Whidbey Island, WA    (503) 989-3649   (日本語でどうぞ)

The Xerces Society is an international nonprofit organization that protects
wildlife through the conservation of invertebrates and their habitat. To
join the Society, make a contribution, or read about our work, please visit
www.xerces.org.


On Fri, Dec 23, 2016 at 10:27 AM, Holmes, Clara (Parks) <
Clara.Holmes at parks.nyc.gov> wrote:

>
> Happy Holidays Everyone,
>
> One of our partners is looking for information regarding isolation
> distances of species. They are trying to set up founder production of the
> following species and one of the sites a grassland is being installed near
> by, potentially compromising the ability to grow many of these species.
> They also want to be sure any hybridization is not occurring among genera
> ie. Euthamia, Lespedeza and Solidago. If anyone has information regarding
> these species it would be greatly appreciated!
>
> Euthamia spp.
> Solidago Spp.
> Schizachyrim scoparium
> Panicum virgatum
> Andropogon gerardii
> Sorghastrum nutans
> Tridens flavus
> Eragrostic spectablitis
> Ionactus linerifolius
> Chrysopsis mariana
> Lespedesa spp.
>
> Cheers,
> Clara
>
> Clara Holmes
> Seed Collection Coordinator
>
> T 718.370.9044 ext. 300 <(718)%20370-9044>
> F 718.370.0932 <(718)%20370-0932>
> E Clara.Holmes at parks.nyc.gov
> E cholmes at marsb.org <Clara.Holmes at parks.nyc.gov>
>
>
>
> *Mid-Atlantic Regional Seed Bank *Greenbelt Native Plant Center
> 3808 Victory Boulevard
> Staten Island, NY 10314
> www.marsb.org
> @_MARSB <https://twitter.com/_MARSB>
>
>
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