Latitudinal and longitudinal barriers in global biogeography

Area of Science:

• Biogeography and Evolutionary Biology
• Paleoclimatology and Paleogeography

Background:

• Earth's changing climate and continental configurations have historically influenced species dispersal and distribution.
• Organisms diversifying during the Gondwanan-Laurasian separation exhibit distinct distribution patterns compared to more recent groups.

Purpose of the Study:

• To map and analyze the biogeographical distribution of two globally distributed taxa using principal component analysis.
• To identify historical dispersal barriers and their impact on the diversification of gymnosperms and bats (chiropterans).

Main Methods:

• Utilized principal component analysis to derive biogeographical maps for two large, globally distributed species groups (approx. 1000 species each).
• Interpreted distribution patterns in the context of paleogeographic events and climate change throughout Earth's history.

Main Results:

• Gymnosperm assemblages clearly demonstrate a division into southern (Gondwanan) and northern (Laurasian) components, reflecting ancient temperate floras.
• Bat (chiropteran) assemblages indicate that longitudinal separation between the Old and New Worlds was the primary Cenozoic dispersal barrier.

Conclusions:

• Ancient continental separation (Gondwanan-Laurasian) created significant latitudinal biogeographical barriers, particularly influencing temperate flora like gymnosperms.
• The diversification and dispersal of bats were primarily shaped by longitudinal barriers arising from continental drift, separating Old and New World populations.