Plant traits and functional types in response to reduced disturbance in a semi-natural grassland

Question: How do functional types respond to contrasting levels of herbage use in temperate and fertile grasslands?Location: Central France (3°°1′′ E, 45°°43′′ N), 870 m a.s.l.Methods: Community structure and the traits of dominant plant species were evaluated after 12 years of contrasted grazing and mowing regimes in a grazing trial, comparing three levels of herbage use (high, medium and low).Results and Conclusions: Of 22 measured traits (including leaf traits, shoot morphology and composition, phenology), seven were significantly affected by the herbage use treatment. A decline in herbage use reduced individual leaf mass, specific leaf area and shoot digestibility, but increased leaf C and dry matter contents. Plants were taller, produced larger seeds and flowered later under low than high herbage use. Nine plant functional response types were identified by multivariate optimization analysis; they were based on four optimal traits: leaf dry matter content, individual leaf area, mature plant height and time of flowering. In the high-use plots, two short and early flowering types were co-dominant, one competitive, grazing-tolerant and moderately grazing-avoiding, and one grazing-avoiding but not -tolerant. Low-use plots were dominated by one type, neither hardly grazing-avoiding nor grazing-tolerant, but strongly competitive for light.Nomenclature: Tutin et al. (1993).Abbreviations: BE == Beginning of flowering period; DI == Digestibility; IT == Height at top of inflorescence; LA == Individual leaf area; LCC == Leaf carbon concentration; LDM == Leaf dry mass; LDMC == Leaf dry matter content; LFM == Leaf lamina fresh mass; LNC == Leaf nitrogen concentration; ME == Flowering plant height, highest leaf elongated; MH == Flowering plant height, highest leaf not elongated; NG == Number of growing green leaves; NM == Number of mature green leaves; PRT == Plant functional response type; RA == Leaf:Shoot dry matter ratio; SLAF == Specific leaf area (fresh mass based); SLAD == Specific leaf area (dry mass based); SM == Seed mass.