Date: Tue, 21 Jan 97 16:46:40 MET From: Paul Temple 21-Jan-1997 1549 <temple_p@fangio.enet.dec.com> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg294$foo@default> Subject: Re: "CLODS"-Value of CP site info, repopulting sites (long-ish!)
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Following Barry's interesting CPN article this little nagging doubt stirred over
the true value of tagging plants with pseudo-exotic location names,
e.g. Utricularia gibba (Tar Lake, Trinidad). No, don't request any; I've seen
it there but I haven't got any!
There has also been a slow but steady related discussion on the practicality of
saving or repopulating a site with plants originally taken from that site, as
denoted by the site name appended to the plant name. I thought I'd comment.
Repopulation first.
In all the discussions, I've seen no mention of population densities. There
have also been suggestions that it is assumed that a small number of plants will
be taken from the wild for any conservation purposes (I'll call these "rescued"
plants). "Small" is a subjective word and the implication is that any "small"
number of rescued plants will be insignificant compared to the actual number of
plants found at the original site.
Reading CPN, it's clear that in America (for example), sites such as those for
Sarracenia are often threatened and this is made all the more apparent when one
is treated to wonderful pictures (or visits to) fields full of Sarracenia,
literally hundreds, if not thousands of plants. Based on examples such as this,
it's not surpising that a "small" number of rescued plants could not fully
replace the biodiversity lost if the whole field got ploughed under!
But fields full of plants are not the norm everywhere, if indeed a norm exists.
My Pinguicula hunts have led me to discover sites where the entire population
numbers maybe as much as 20 plants. Say, for example, that I can remove one
seed pod (with permission!!!) containing a small number of seeds (let's say 35
seed, about normal for a cross pollination). Although I have a "small" number
(35) of seeds, I actually have more potential plants than the entire population
of plants growing in the source location! As to biodiversity, in such a
situation, it is probable that there will be more biodiversity in the 20 wild
plants than in the resulting 35 cultivated seedlings but this is neither certain
nor is it necessarily significant as, with such small numbers in the wild, any
new seedlings will in themselves increase the biodiversity significantly (as
long as they are not all replanted back in the wild whereby their limited
biodiversity might smother the wild original). Further, by placing some of
these cultivated plants back in the wild, I can gain an opportunity to collect
seed from a different plant. I can also take every opportunity to "lend a hand"
and cross pollinate any flowers I can find in the wild. Work it out. For
species where the original population is small, this results in a near
exponential growth in biodiversity assuming seed is collected and grown
successfully from successive generations. Therefore it is not only one of very
few ways (if not the only way) to conserve a plant under dire threat, it is also
both viable and pragmatic and even an improvement on what natural processes
might be expected to achieve.
But back to the Sarracenia field (I wish!). Suppose over a period of 20 years
lots of people visit the field, some taking plants (surely not), others taking
seeds (and some taking only memories). If they all kept decent provenance
records or if the tagged the location name to the plant name, then potentially
even a field full of thousands of plants may be able to be matched by the sheer
weight of material collected over the years. Using such well documented
plants, a breeding p[rogramme could be set up to ensure the maximum biodiversity
was gained by multiple cross pollination of different partners. Effectively
this is identical to the procedure now adopted for rescuing threatened animal
species, it's just that I've never heard of its application to plants. But why
not? Surely another project a world wide CP conservation body could conduct
(remember, you heard it first here!). Either a geneticist or a mathematician
could work out how many crosses of which plants would be needed to replace a
wild population lost to a catastrophe (e.g. a plough).
There is some more maths that could be done on this.
Perhaps a mathematician amoungst us might like to look at the issue of very
small populations from a purely mathematical point of view. In the wild: assume
20 plants; assume about 5% germination success with an average of 35 seeds per
seed pod, assume 4 - 5 flowers per plant per year, assume 50% of the plants
flower each year; assume seedlings take 2 years to flower in the wild. In
cultivation, assume 90% germination success; assume seedlings take 1 year to
flower; assume other factors equal. How many seedpods would need to be taken
into cultivation to significantly increase the biodiversity after 1 year, 2
years, 5 years. If a single seed is taken from the wild and if the resultant
plant is self pollinated with a resultant 30 - 35 seedlings how many further
generations of plants would need to be cross pollinated to create a cultivated
group with the same biodiversity as the wild group of 20 plants. (This would
need a botanist to assist - with estimates of wild biodiversity and same for
cultivated seedlings from a selfed plant). Sorry to get all theoretical but I
happen to like this sort of stuff andf I feel it may in any case have a
practical result - perhaps some sort of "what if" mathematical model? Can the
model apply to any size population? (Why not?) Anyone out there able to take
the challenge? (Spock - where are you?)
As to appending those exotic names, OK, I agree in general with what Barry says.
And at least one other person has added comments in the conference. But I'll
also add that these "names" are a short cut which can be helpful scientifically.
Why a short cut? Because if anyone is collecting plants (or preferably seed),
then to be of any use scientically the provenance (details of where and when the
plant was found) must be recorded. Many plants are collected with inadequate
provenance details (and we've already heard that this now should include proof
of permission to collect). And most collectors do not have full documentation
processes for their plants (e.g. full written records). So the onlyy way that
the source location may be recorded is by making it a part of the plant's name.
OK, it's not scientific but those who understand the science understand what is
going on and those who don't understand the science don't mind! From
experience, I can tell you that the location name, whether tagged on as part of
the name or recorded separately (properly), can then help in future
identification of the plant. When searching through herbarium records I have
actually been able to link my plants to those found by others based partially on
the plant description but also on the loaction at which each collector found the
plant. And even this can give a clue as to conservation needs. If all the
plants found are from small populations and if each separate discovery is always
from the same location, one can soon begin to hypothesise that not too many
locations or plants exist.
But back to reality. There are two real reasons why most people tack on the
location names (or indeed other epithets such as "heavily veined", "red tube
green lid", green tube red lid", "giant", "pygmy", etc.) . The collectors use
it to turn a small collection into a large one (U. gibba is one plant. U.
gibba (Tar Lake, Trinidad) and U.gibba (Aripo) are two plants. The fact that
they are botanically identical doesn't count where our residual caveman
hunter/gatherer extincts are to be satisfied! And for the entrepreneur, there
is yet another opportunity to charge a lot for that very special plant that
no-one has. After all, which would sell better, Pinguicula sp. or Pinguicula
sp. (Cuba)!!! (My hat is off to Harald Weiner who made a living out of doing
this. I wonder where/how he is now?)
Regards
Paul
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