Ecosystem diversity in southern African savannas is fueled by pyrodiversity

Abstract

African savannas are experiencing a rapid decline in burned area, often entailing a simplification of landscape pyrodiversity. We used virtual landscapes generated from data collected in a multi-decadal fire experiment to test how pyrodiversity (measured as spatial variation in fire frequency) shapes multiple dimensions of three savannas spanning a rainfall gradient in South Africa. Results provide empirical evidence that pyrodiversity begets diversity across structural, functional, and taxonomic dimensions, especially at precipitation ≥650 mm yr⁻1. The positive effects of pyrodiversity arise because patches with different fire frequencies form a diverse landscape mosaic. Critically, the highest woody encroachment, carbon storage, soil nitrogen and woody species diversity was found in low fire frequency patches. On the contrary, the most diverse ground vegetation communities were detected in frequently burned patches. Our findings emphasize the importance of pyrodiversity-based management for maintaining ecosystem diversity and associated services in the face of ongoing environmental changes. Pyrodiversity leads to structural, functional, and taxonomic diversity in savannas, driven by landscapes with varying fire frequencies, based on data from a multi-decadal fire experiment across a rainfall gradient in South Africa