G. robertsoniae and sustainable seed collecting

Michael Mace michaelcmace@gmail.com
Fri, 18 Nov 2011 10:09:40 PST
Alberto wrote:

> If they are rare species living as a single tiny population should people
buy it?

In the case of G. robertsoniae, the photos that accompany the article show
what looks like thousands of individuals at the sites where it grows best.
I personally believe a small amount of seed collecting at one of those
sites, done in a year when it blooms abundantly, would be a net benefit to
the species because it would get it established in cultivation.  

But I think Alberto's asking a more general question, and it's worth
discussing.  If a bulb is rare, when is it proper and not proper to collect
material from it, for the net benefit of a species?  Is it ever OK to dig
bulbs from a rare species (the only time I can think of is when the
bulldozers are coming tomorrow)?  How many individuals need to be growing in
order to make it safe to collect seeds?  What percent of the seeds should
you take at maximum?  How often?  If you collect in a situation like this,
should you plant some of the seeds on site (presumably to reduce predation,
offsetting the loss caused by what you took)?

The problem with any red list of endangered plants is that they get on the
list through multiple paths.  If you read through the South African list,
some of the most endangered plants are on the list because they have a
protected location, but there are only a few individuals in the wild.
Moraea loubseri comes to mind.  To me, it's hard to justify collecting more
seed from that one in the wild.  Others species are on the list because
they're locally abundant but growing in only a few sites that have no formal
protection.  G. robertsoniae sounds like the latter from what I've read.
Those might be prime candidates for some careful seed collection, as a
lifeboat for the species. 

I have heard anecdotal "rules of thumb" from various seed collectors in the
US and elsewhere on when to collect, how much, etc, but I've never heard of
any agreed guidelines.  Do those guidelines exist?  If not, can we create
some?  I don't know who else would do it, and I'd like to know that any
seeds I buy have been "sustainably harvested."

San Jose, CA

More information about the pbs mailing list