FIG. 48.21 Latitudinal diversity gradient in vascular plants. Species diversity is highest in the wet tropics and declines toward the poles. Data from Jens Mutke and Wilhelm Barthlott, 2008, “Biodiversität und ihre Veränderung im Rahmen des Globalen Umweltwandels: Biologische Aspekte” (Biodiversity and its change in the context of global environmental change: biological aspects) In Dirk Lanzerath, Jens Mutke, Wilhelm Barthlott, Stefan Baumgärtner, Christian Becker, and Tade M. Spranger, 2008, Biodiversität (Biodiversity.) (Ethik in den Biowissenschaften– s–