Rare species

[Thomas G. Lammers]

At 09:39 AM 07-30-97 -0700, Dennis Paulson wrote:

>Thomas Lammers wrote that
>populations of the "lots of individuals in one or a few tiny areas" type
>are more at risk than those of the "few individuals scattered over a large
>area" type, and I can see his point. However, the former types are much
>more easily protected than the latter, so I don't agree that the latter are
>necessarily more secure. Because they are so scarce, they can disappear
>literally before we know it, whereas the concentrated, local populations
>can be more effectively monitored.

Point well taken, assuming that there is some mechanism for monitoring and
protection available.  I was thinking of situations (e.g., outside USA
borders) were there is little or no legal protection available, or where our
knowledge of the environment is so preliminary that we don't have good data
yet on rarity, distribution, etc.   I was thinking of a species of
angiosperm existing as thousands of individuals atop a single peak in, e.g.,
Peru, vs. a congener that occurs as scattered plants or small populations
along the length of the Andes.  One well placed logging camp could extirpate
the former in a single day, the other could survive many logging camps.  But
you are right: if the forces that are causing mortality to exceed
recruitment are pervasive enough,  a wide-ranging but "sparce" species can
disappear  while we are lulled into a false sense of security by its wide
distribution.


Thomas G. Lammers

Classification, Nomenclature, Phylogeny and Biogeography
of the Campanulaceae, s. lat.

Department of Botany
Field Museum of Natural History
Roosevelt Road at Lake Shore Drive
Chicago, Illinois 60605-2496 USA

e-mail:     lammers at fmppr.fmnh.org
voice mail: 312-922-9410 ext. 317

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