Intense solar radiation constrains plant species richness in global grasslands
The search for predictors of plant diversity has challenged scientists for decades. Here we identify intense photosynthetically active radiation (PAR) as a major factor constraining plant species richness in global grasslands. We show that the strength of the negative relationship between species richness and PAR increases with increasing elevation and that species richness is more strongly correlated with intense PAR than with UV-B radiation, climate variables, and atmospheric nitrogen deposition. In addition to species richness, plant biomass was also negatively correlated with PAR at higher elevations, indicating that intense PAR also constrains plant biomass in montane grasslands. Furthermore, we show that the decrease in plant species richness with increasing PAR is mainly caused by a decrease in species richness of forbs, sedges, and rushes. In contrast, species richness of grasses was only negatively correlated with PAR at high elevations, and species richness of legumes was not significantly correlated with PAR. Our results suggest that PAR constrains plant species richness in global grasslands and limits the extent to which plant species of specific functional groups can migrate uphill in response to climate warming.
Authors
- Marc W. Cadotte (ORCID: https://orcid.org/0000-0002-5816-7693)
- Clinton Carbutt (ORCID: https://orcid.org/0000-0002-1540-0029)
- Ramesh Laungani
- Steven C. Pennings (ORCID: https://orcid.org/0000-0003-4757-7125)
- Kyle E. Harms (ORCID: https://orcid.org/0000-0002-8842-382X)
- Marie Spohn (ORCID: https://orcid.org/0000-0002-1010-7317)
- Mary Ellyn DuPre (ORCID: https://orcid.org/0000-0002-1567-2681)
- Holly M. Martinson (ORCID: https://orcid.org/0000-0003-1462-0051)
- Pengfei Zhang (ORCID: https://orcid.org/0000-0002-5753-7023)
- Risto Virtanen (ORCID: https://orcid.org/0000-0002-8295-8217)
- Carlos Alberto Arnillas (ORCID: https://orcid.org/0000-0003-1506-9978)
- Christiane Roscher (ORCID: https://orcid.org/0000-0001-9301-7909)
- Nicole Hagenah (ORCID: https://orcid.org/0000-0002-3864-2469)
- Kari Anne Bråthen
- Glenda M. Wardle (ORCID: https://orcid.org/0000-0003-0189-1899)
- Jonathan D. Bakker (ORCID: https://orcid.org/0000-0002-8973-2771)
- Anita C. Risch (ORCID: https://orcid.org/0000-0003-0531-8336)
- Sally A. Power (ORCID: https://orcid.org/0000-0002-2723-8671)
- Lauri Laanisto (ORCID: https://orcid.org/0000-0003-2215-7298)
- Meelis Pärtel
- Yann HAUTIER
- Jonathan Millett
- Sylvia Haider
- E. T. Borer
- E. Hersch-Green
- C. Stevens
- P. Macek
- E. W. Seabloom
- N. G. Smith
- C. Estrada
- J. M. H. Knops
- Ciara Dwyer
- Jane A. Catford
- Pablo L. Peri
- Nico Eisenhauer
Institutions
- Leuphana University of Lüneburg (DE)
- Australian National University (AU)
- Michigan Technological University (US)
- Louisiana State University (US)
- Texas Tech University (US)
- The University of Sydney (AU)
- University of Minnesota (US)
- Loughborough University (GB)
- McDaniel College (US)
- King's College London (GB)
- University of Toronto (CA)
- Lund University (SE)
- Utrecht University (NL)
- Estonian University of Life Sciences (EE)
- University of Washington (US)
- Czech Academy of Sciences (CZ)
- Scarborough Health Network (CA)
- Swiss Federal Institute for Forest, Snow and Landscape Research (CH)
- German Centre for Integrative Biodiversity Research (DE)
- Mammal Research Institute (PL)
- Swedish University of Agricultural Sciences (SE)
- Ministry of Agriculture (EE)
- Marist School (US)
- Scientific Services (ZA)
- Instituto Nacional de Tecnologia (BR)
- Department of Physiological Sciences (RU)
- Ecologie microbienne (FR)
- Czech Academy of Sciences, Biology Centre (CZ)
- Ecosystem Sciences (AU)
- University of Houston (US)
- Imperial College London (GB)
- Life University (US)
- University of Tartu (EE)
- Western Sydney University (AU)
- Lancaster University (GB)
- Xi’an Jiaotong-Liverpool University (CN)
- University of Pretoria (ZA)
- UiT The Arctic University of Norway (NO)
- Leipzig University (DE)
- University of KwaZulu-Natal (ZA)
- University of Oulu (FI)
Publication Details
- Journal
- Proceedings of the National Academy of Sciences
- Published
- 2026-02-05
- DOI
- https://doi.org/10.1073/pnas.2527128123
- Citations
- 1
- Primary Topic
- Remote Sensing in Agriculture
- Type
- article
- Field-Weighted Citation Impact
- 31.91
Funders
- National Science Foundation
- National Aeronautics and Space Administration
- Louisiana State University
- Eesti Teaduste Akadeemia
- Lanzhou University
- Natural England
- Leverhulme Trust
- Imperial College London
- Deutsche Forschungsgemeinschaft
- National Natural Science Foundation of China
- Eesti Teadusagentuur
- Natural Sciences and Engineering Research Council of Canada