Leon Croizat

Leon Croizat was a Venezuelan phytogeographer who challenged the prevailing dispersalist explanation of species distribution. Phytogeography is the study of the geographical distribution of plants. Croizat argued that the regularity of biogeographic relationships was too significant to be attributed to chance barrier crossings. His ideas, developed in the 1950s and 1960s, were influential in the later development of vicariance theory, which posits that species distribution patterns arise from the fragmentation of a once-continuous range by geological or environmental barriers. While dispersalist and vicariance biogeography have historically been at odds, many scientists now believe that both processes contribute to understanding distributional diversity.12