Doug Yanega dyanega at POP.UCR.EDU
Wed Sep 4 11:25:11 CDT 2002

Stephen Manning wrote:

>>Clearly, every organism has habitat preferences, but these
>>preferences can be overridden in many cases. It seems to me that any
>>model based solely on preferences is going to miss many marginal
>>and/or suboptimal areas where a species could (or does) survive, and
>>for endangered species, especially, that's a VERY risky approach to
>>What does one do then?
>How about including locality data of existing collections of the species as
>part of the model?  The data entered into the model could then, if the
>model is flexible enough, be modified each time a range extension is

Maybe you misunderstood - when the model using locality data of
existing collections resulted in too large a potential range map, the
modeler *reduced* what they considered to be the potential range by
excluding outlying data until they liked the resulting map; instead
of range extensions, these data points are now considered
"transients" - based not on evidence that they are in fact
transitory, but because the model fails to generate satisfactory maps
when they're included - they argue that the data is bad, rather than
the model. Each time a new range extension is discovered, it's
*ignored* if it's outside the present boundaries predicted by the
model - they classify the data points so they don't get used in the
model (rather than revising the model), and are advocating
conservation decisions based on the reduced model. I was asking what
one must do to counter that approach. If no one here has ideas, maybe
we should take this off-list or drop it entirely.


Doug Yanega        Dept. of Entomology         Entomology Research Museum
Univ. of California - Riverside, Riverside, CA 92521
phone: (909) 787-4315 (standard disclaimer: opinions are mine, not UCR's)
   "There are some enterprises in which a careful disorderliness
         is the true method" - Herman Melville, Moby Dick, Chap. 82

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