Abstract:
:Tropical diversity has generally exceeded temperate diversity in the present and at points in the past, but whether measured differences have remained relatively constant through time has been unknown. Here we examine tropical vs. temperate diversities from the Neogene to Recent using the within-habitat diversity measure Fisher's alpha of Cenozoic benthic foraminifera from the temperate Central Atlantic Coastal Plain and the tropical Central American Isthmus. During the Neogene, the mean value of alpha at temperate latitudes increased 1.4 times or 40%, whereas in the tropics it increased 2.1 times or 106%. Thus, while both areas exhibit an increase of diversity with time, past differences in the rate of increase have generated a more pronounced gradient today (164%) than existed in the Miocene (80%). These data disagree with the suggestion that the world reached an equilibrium number of species during the Paleozoic and demonstrate the need to consider both temperate and tropical components in global diversity assessments.
journal_name
Proc Natl Acad Sci U S Aauthors
Buzas MA,Collins LS,Culver SJdoi
10.1073/pnas.122241499keywords:
subject
Has Abstractpub_date
2002-06-11 00:00:00pages
7841-3issue
12eissn
0027-8424issn
1091-6490pii
99/12/7841journal_volume
99pub_type
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