Florian Hartig Theoretical Ecology & Ecological Data Science

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Environmental heterogeneity predicts global species richness patterns better than area

Kristy Udy, Matthias Fritsch, Katrin M. Meyer, Ingo Grass, Sebastian Hanß, Florian Hartig, Thomas Kneib, Holger Kreft, Collins B. Kukunda, Guy Pe'er, Hannah Reininghaus, Britta Tietjen, Teja Tscharntke, Clara-Sophie van Waveren, Kerstin Wiegand

Global Ecology and Biogeography, 30(4), 842–851 (2021)
Cite this
@article{udy2021environmental,
  author = {Kristy Udy and Matthias Fritsch and Katrin M. Meyer and Ingo Grass and Sebastian Hanß and Florian Hartig and Thomas Kneib and Holger Kreft and Collins B. Kukunda and Guy Pe'er and Hannah Reininghaus and Britta Tietjen and Teja Tscharntke and Clara-Sophie van Waveren and Kerstin Wiegand},
  title = {Environmental heterogeneity predicts global species richness patterns better than area},
  journal = {Global Ecology and Biogeography},
  volume = {30},
  number = {4},
  pages = {842–851},
  year = {2021},
  doi = {10.1111/geb.13261},
}

DOI: 10.1111/geb.13261
Cited by 99 (Google Scholar) · 88 (OpenAlex), as of 07 September 2026

View article (DOI)

Abstract

It is widely accepted that biodiversity is influenced by both niche-related and spatial processes from local to global scales, but their relative importance is still disputed, and empirical tests are surprisingly scarce at the global scale. Here, we compare the importance of area (as a proxy for pure spatial processes) and environmental heterogeneity (as a proxy for niche-related processes) for predicting native mammal species richness world-wide and within biogeographical regions, applying a spreading dye algorithm to a global snapshot of IUCN richness data for all terrestrial mammal species, using elevation ranges and precipitation ranges as measures of environmental heterogeneity. We found that environmental heterogeneity explained species richness relationships better than did area, suggesting that niche-related processes are more prevalent than pure area effects at broad scales. Our results imply that niche-related processes are essential to understand broad-scale species-area relationships, and that habitat diversity is more important than area alone for the protection of global biodiversity.

What the paper shows and why it matters (AI-generated)

The classic species-area relationship treats area as the main predictor of how many species a region holds, but this global analysis of IUCN mammal range data finds environmental heterogeneity — elevation and precipitation variation — explains richness patterns better than area does, across biogeographic regions worldwide. For conservation planning that's a real, actionable distinction: it argues for prioritising habitat diversity within a protected area, not just maximising the area's size.