Global patterns of vascular plant alpha diversity

Area of Science:

• Ecology
• Botany
• Biodiversity Science

Background:

• Global patterns of regional (gamma) plant diversity are well-documented.
• However, the applicability of these patterns to local communities (alpha diversity) and their dependence on spatial grain remain debated.

Purpose of the Study:

• To create global maps of vascular plant alpha diversity at three spatial grains (fine, intermediate, coarse) for forests and non-forests.
• To investigate regional variations in diversity patterns and the influence of spatial grain.
• To analyze how climatic, topographic, and biogeographical factors affect alpha diversity across different grains.

Main Methods:

• Utilized a dataset of 170,272 georeferenced local plant assemblages.
• Generated global maps of alpha diversity for vascular plants at three distinct spatial grains.
• Analyzed diversity patterns in forest and non-forest ecosystems.

Main Results:

• Alpha diversity patterns are not uniform across spatial grains; some regions show consistent high diversity (e.g., Andean-Amazonian foothills).
• Identified 'scaling anomalies' where diversity patterns deviate from expectations, such as higher fine-grained richness in Eurasian temperate forests and higher coarse-grained richness in African tropical forests.
• Demonstrated that the influence of environmental variables on alpha diversity is scale-dependent.

Conclusions:

• Multi-grain analysis provides a more nuanced understanding of global vascular plant biodiversity than traditional hotspot maps.
• These findings are essential for improving predictions of biodiversity responses to global change.
• Highlights the importance of considering spatial grain in biodiversity research and conservation efforts.