title: What functional strategies drive drought survival and recovery of perennial species from upland grassland?
abstract: OBJECTIVE
  Extreme climatic events such as severe droughts are expected to increase with climate change and to limit grassland perennity. The present study aimed to characterize the adaptive responses by which temperate herbaceous grassland species resist, survive and recover from a severe drought and to explore the relationships between plant resource use and drought resistance strategies.
  
  
  METHODS
  Monocultures of six native perennial species from upland grasslands and one Mediterranean drought-resistant cultivar were compared under semi-controlled and non-limiting rooting depth conditions. Above- and below-ground traits were measured under irrigation in spring and during drought in summer (50 d of withholding water) in order to characterize resource use and drought resistance strategies. Plants were then rehydrated and assessed for survival (after 15 d) and recovery (after 1 year).
  
  
  RESULTS
  Dehydration avoidance through water uptake was associated with species that had deep roots (>1·2 m) and high root mass (>4 kg m(-3)). Cell membrane stability ensuring dehydration tolerance of roots and meristems was positively correlated with fructan content and negatively correlated with sucrose content. Species that survived and recovered best combined high resource acquisition in spring (leaf elongation rate >9 mm d(-1) and rooting depth >1·2 m) with both high dehydration avoidance and tolerance strategies.
  
  
  CONCLUSIONS
  Most of the native forage species, dominant in upland grassland, were able to survive and recover from extreme drought, but with various time lags. Overall the results suggest that the wide range of interspecific functional strategies for coping with drought may enhance the resilience of upland grassland plant communities under extreme drought events.
authors: INRA, UR874, Grassland Ecosystem Research Team, 5 chemin de Beaulieu, F-63039 Clermont-Ferrand, France.
authors: Marine
authors: M
authors: Zwicke
authors: INRA, UR874, Grassland Ecosystem Research Team, 5 chemin de Beaulieu, F-63039 Clermont-Ferrand, France, catherine.cochard@clermont.inra.fr.
authors: Catherine
authors: C
authors: Picon-Cochard
authors: Normandie Université, France, UCBN, UMR 950 Ecophysiologie Végétale and Agronomie, Nutritions NCS, F-14032 Caen, France, INRA, UMR 950 EVA, F-14032 Caen, France and.
authors: Annette
authors: A
authors: Morvan-Bertrand
authors: Normandie Université, France, UCBN, UMR 950 Ecophysiologie Végétale and Agronomie, Nutritions NCS, F-14032 Caen, France, INRA, UMR 950 EVA, F-14032 Caen, France and.
authors: Marie-Pascale
authors: MP
authors: Prud'homme
authors: INRA, USC 1338, CEFE UMR 5175, Université de Montpellier-Université Paul Valéry-EPHE, 1919 route de Mende, F-34293 Montpellier Cedex 5, France.
authors: Florence
authors: F
authors: Volaire
mesh_terms: D057231:Climate Change; D055864:Droughts; D065948:Grassland; D018515:Plant Leaves / Q000502:physiology; D018517:Plant Roots / Q000502:physiology; D006109:Poaceae / Q000502:physiology*; D012621:Seasons; D014867:Water / Q000502:physiology*
chemical_list: D014867:Water
keywords: Dehydration avoidance; dehydration tolerance; drought survival; forbs; fructans; functional traits; grasses; membrane stability; resilience index; root system; sucrose; upland grassland