Lifemapper

[Thomas DiBenedetto]

-----Original Message-----
From: Robert Mesibov
....
While I respect the efforts and intentions of range modellers, I can't help
thinking that modelling is no substitute for field work,...

I wonder about the goals of predictive range modellers. I understand that if
one were to have a well-working model, capable of predicting areas where
particular species might be found, that that might be an interesting thing.
However I dont see that as being really very useful. My instinct would be to
agree wholeheartedly with Robert about the primacy of observations in the
field when it comes to defining the actual range of species.
This is not to say however, that I dont see great use for predictive models,
but it is not for the predictions per se. As I see it, the model serves as a
vehicle for organizing our knowledge of the factors that influence
distributions. The models will incorporate some factors, may choose not to
incorporate others, and will necessarily define relationships between the
factors. All of this equals a complex hypothesis regarding the causes for
particular distributions. Armed with the output of such models, we can then
examine real-world distributions as a test of the models. And in such a
manner, we can refine the models until we arrive at a model that best
indicates that which we find in nature. We will then have reason to claim to
having increased our knowledge of why species are distributed as they are.
Yet I constantly hear discussions of these models that seem to indicate that
their proponents are not so much focussed on seeing the models as formal,
general hypotheses, but as useful predictors of actual occurences. Even if
they were, I dont see that as anywhere near their most valuable use.

Tom diBenedetto