Spatial dynamics

Abstract

As defined in Chapter 1, the designation of species as rare or otherwise is made with reference to a particular area or spatial scale. Having been established, the categories might usefully be employed to investigate questions in other areas and at other scales. As emphasized, this approach agrees with the bulk of past applications of the term rare. Nonetheless, it still has to be determined whether there is any tendency for species which have been defined as rare in one area also to be defined as rare in another. That is, do species demonstrate spatially concordant rarity? In a similar vein, Schoener (1987, 1990) posed the question whether rarity (in his sense of occurrence in relatively few censuses and/or at relatively low abundances) was typically diffusive or typically suffusive. A species that was diffusively rare would be one which although rare in certain parts of its geographic range was common in others, while a suffusively rare species would be one which was rare everywhere.

Nothing puzzles me more than time and space; and yet nothing troubles me less, as I never think about them. C. Lamb (1810)