The article by Holger Kreft and Walter Jetz investigates the global patterns and determinants of vascular plant diversity. They analyze species richness across 1,032 geographic regions, focusing on environmental and historical factors. Key findings include: 1. **Environmental Predictors**: Potential evapotranspiration, the number of wet days per year, and topographical and habitat heterogeneity are core predictors of species richness. 2. **Historical Contingencies**: The South African Cape region stands out for its exceptionally high species richness, confirming its unique evolutionary history. 3. **Modeling**: A combined multipredictor model explains about 70% of the global variation in species richness, accounting for the latitudinal gradient in species richness. 4. **Interactions**: Water-energy dynamics play a dominant role, with interactions between potential evapotranspiration and the number of wet days being particularly significant. 5. **Geostatistical Approach**: The study demonstrates the utility of geostatistical methods in predicting species richness patterns, which can be applied to other taxa with limited distribution data. The authors conclude that different hypotheses about the causes of diversity gradients are not mutually exclusive but likely act synergistically, highlighting the importance of both environmental and historical factors in shaping plant diversity.The article by Holger Kreft and Walter Jetz investigates the global patterns and determinants of vascular plant diversity. They analyze species richness across 1,032 geographic regions, focusing on environmental and historical factors. Key findings include: 1. **Environmental Predictors**: Potential evapotranspiration, the number of wet days per year, and topographical and habitat heterogeneity are core predictors of species richness. 2. **Historical Contingencies**: The South African Cape region stands out for its exceptionally high species richness, confirming its unique evolutionary history. 3. **Modeling**: A combined multipredictor model explains about 70% of the global variation in species richness, accounting for the latitudinal gradient in species richness. 4. **Interactions**: Water-energy dynamics play a dominant role, with interactions between potential evapotranspiration and the number of wet days being particularly significant. 5. **Geostatistical Approach**: The study demonstrates the utility of geostatistical methods in predicting species richness patterns, which can be applied to other taxa with limited distribution data. The authors conclude that different hypotheses about the causes of diversity gradients are not mutually exclusive but likely act synergistically, highlighting the importance of both environmental and historical factors in shaping plant diversity.