Species Movement in Zoogeography

Seventy-five years of mammalogy, 1919-1994

“…In current terminology this is simply a vicariant event and the original hypothesis about different areas of different sizes and about vigor seems irrelevant, at least as it relates to Asia and North America. A probabilistic model was discussed by Horton (1974), basically as a null hypothesis, and the conclusion was reached that it is not 219.…”

Major Patterns in Vertebrate Evolution

“…The Holarctic, because of its sheer size would be expected to produce a high proportion of new lines. Horton (1974a) makes this point, noting that if two areas, both with all their niches full, are exchanging species, then more movement will take place from the area with the larger number of species, simply because it has the larger number of potential immigrants. Horton also suggests that smaller areas are likely to have unoccupied niches (in contrast to the larger ones), making it easier for them to be colonized.…”