Highlights• We conducted a species-area analysis of comprehensive regional floras of three tropical and the five Mediterranean-climate regions of the world.• Among tropical regions, the highest diversities were recorded in the Neotropics and Southeast Asia, with the Afrotropics generally recording the lowest diversities.• The floras of Mediterranean-climate regions showed high variation: the Cape region recorded the second highest diversity after a Neotropical Andean flora; the Mediterranean Basin and Southwestern Australian floras were comparably rich as many Neotropical and Southeast Asian floras; and California and Chile have floras richer than many Afrotropical regions.• The fact that the most plant-rich parts of the globe are shared amongst tropical and temperate regions challenges the hypothesis that global patterns of diversity are best explained by water-energy dynamics. Historical processes underpinned by high biome stability and high ecological heterogeneity are likely to be more effective predictors of global plant diversity patterns.

Aim: The expansion of subtropical thicket vegetation at the expense of more species-rich, fire-prone fynbos, potentially due to lower frequency and severity of fire and browsing, is a concern in many coastal dune landscapes of the Cape Floristic Region (CFR) where these two vegetation types co-occur. We were interested in the effects of severe fire and browsing treatment on the vigour of post-fire resprouts of dune thicket shrubs. Location: Cape St Francis, CFR, South Africa. Methods: We used an in-situ experimental approach to compare the effects of simulated fire and browsing by herbivores on mortality, resprouting vigour and resprouting rate of ten canopy-forming dune thicket shrub species from different architectural guilds, five years after a previous severe wildfire. Results: Survival was significantly lower after fire (85%) than after browsing (95%), and was significantly positively related to pre-treatment shrub size. All measures of resprouting vigour were significantly lower after fire than after browsing, and were significantly positively related to pre-treatment size. Resprouting rate was significantly lower after fire than after browsing, and was significantly positively affected by pre-treatment size. Survival and measures of resprouting vigour were generally decoupled from architectural guild and species identity. Conclusion: Dune thicket shrubs showed high survival after both fire and browsing treatments, suggesting that these species are resilient to frequent, severe defoliation disturbances. Our results suggest that short interval fires (5-15 years) of high severity will merely maintain the co-occurrence of dune fynbos and thicket vegetation by setting back thicket growth rather than causing large-scale mortality of thicket shrubs.