On the Relationship between Abundance and Distribution of Species

摘要: There appears to be a general relationship between abundance and distribution that has two parts. First, within species, population density tends greatest in the center of range decline gradually toward boundaries. This pattern holds over spatial scales from steep environmental gradients local regions entire geographic range. Exceptions include: (1) abrupt changes usually correspond sharp, discontinuous single variables; (2) multimodal patterns are caused by patchiness. The second is among closely related, ecologically similar species positively correlated with average abundance. Again this variety ranges. These empirical have already been reported literature, but their generality demonstrated analysis additional data for divers...