Tree diversity does not always improve resistance of forest ecosystems to drought

TY - JOUR

T1 - Tree diversity does not always improve resistance of forest ecosystems to drought

AU - Grossiord, Charlotte

AU - Granier, André

AU - Ratcliffe, Sophia

AU - Bouriaud, Olivier

AU - Bruelheide, Helge

AU - Chećko, Ewa

AU - Forrester, D.I.

AU - Dawud, Seid Muhie

AU - Finér, Leena

AU - Pollastrini, Martina

AU - Scherer-Lorenzen, Michael

AU - Valladares, Fernando

AU - Bonal, Damien

AU - Gessler, Arthur

PY - 2014/10/14

Y1 - 2014/10/14

N2 - Climate models predict an increase in the intensity and frequency of drought episodes in the Northern Hemisphere. Among terrestrial ecosystems, forests will be profoundly impacted by drier climatic conditions, with drastic consequences for the functions and services they supply. Simultaneously, biodiversity is known to support a wide range of forest ecosystem functions and services. However, whether biodiversity also improves the resistance of these ecosystems to drought remains unclear. We compared soil drought exposure levels in a total of 160 forest stands within five major forest types across Europe along a gradient of tree species diversity. We assessed soil drought exposure in each forest stand by calculating the stand-level increase in carbon isotope composition of late wood from a wet to a dry year (Δδ13CS). Δδ13CS exhibited a negative linear relationship with tree species diversity in two forest types, suggesting that species interactions in these forests diminished the drought exposure of the ecosystem. However, the other three forest types were unaffected by tree species diversity. We conclude that higher diversity enhances resistance to drought events only in drought-prone environments. Managing forest ecosystems for high tree species diversity does not necessarily assure improved adaptability to the more severe and frequent drought events predicted for the future.

AB - Climate models predict an increase in the intensity and frequency of drought episodes in the Northern Hemisphere. Among terrestrial ecosystems, forests will be profoundly impacted by drier climatic conditions, with drastic consequences for the functions and services they supply. Simultaneously, biodiversity is known to support a wide range of forest ecosystem functions and services. However, whether biodiversity also improves the resistance of these ecosystems to drought remains unclear. We compared soil drought exposure levels in a total of 160 forest stands within five major forest types across Europe along a gradient of tree species diversity. We assessed soil drought exposure in each forest stand by calculating the stand-level increase in carbon isotope composition of late wood from a wet to a dry year (Δδ13CS). Δδ13CS exhibited a negative linear relationship with tree species diversity in two forest types, suggesting that species interactions in these forests diminished the drought exposure of the ecosystem. However, the other three forest types were unaffected by tree species diversity. We conclude that higher diversity enhances resistance to drought events only in drought-prone environments. Managing forest ecosystems for high tree species diversity does not necessarily assure improved adaptability to the more severe and frequent drought events predicted for the future.

U2 - 10.1073/pnas.1411970111

DO - 10.1073/pnas.1411970111

M3 - Journal article

C2 - 25267642

SN - 0027-8424

VL - 111

SP - 14812

EP - 14815

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

IS - 41

ER -