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

Abstract

Abstract. 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.

How do sheep affect plant communities and arthropod populations in temperate grasslands?

“…Impact of stocking rate Decreasing stocking rate in our set of seminatural or fertilized temperate pastures led to an increase in the mean SSH ( Figure 1): Conversely, we did not find a global effect of stocking rate on plant species richness (F 1.47 5 0.31; P 5 0.58; Figure 2), despite significant effects in some experiments showing evidence of a detrimental effect of intensive grazing (Bullock et al, 2001;Dorrough et al, 2004;Louault et al, 2005) or of grassland abandonment (Fothergill et al, 2002;Sebastià et al, 2008), Impact of sheep on grassland biodiversity as predicted by the unimodal response of diversity along disturbance gradients (Grime, 1979). After a change in grazing intensity, species abundance changes more rapidly than plant species richness (Marriott et al, 2002;Louault et al, 2005;Scimone et al, 2007).…”

“…After a change in grazing intensity, species abundance changes more rapidly than plant species richness (Marriott et al, 2002;Louault et al, 2005;Scimone et al, 2007). However, we could not find any global effect of stocking rate on the Shannon index (F 1.30 5 0.06; P 5 0.81; Figure 3) or other indicators of plant community evenness (log normal diversity index: Bullock et al, 2001; Simpson dominance index: Scimone et al, 2007).…”

Grass strategies and grassland community responses to environmental drivers: a review

“…For example, productive meadows tend to be dominated by tall, fast growing species (Louault et al 2005) that can develop a disproportionately large competitive effect on local resources (e.g. light and nutrient, Grime et al 1997).…”

Development of a functional approach in a grassland vegetation

“…Broad functional responses based on well-demonstrated biological laws and long developed theoretical frameworks were to be used to reach the target without creating an overly complicated model (Pérochon et al, 2001;Baumont et al, 2002;Carrère et al, 2002). The role of such a model could be to explore a large number of hypotheses in the spatiotemporal heterogeneity in plant-animal interactions (Marriott and Carrère, 1998;Laca, 2000). Recent researches in natural and semi-natural European grassland vegetation are focusing on the reduction of the intensity of grassland ecosystem utilization (Louault et al, 2005).…”

“…These are to provide a simplified framework to better understand grazing systems and to be able to simulate their complexity (Marriott and Carrère, 1998). The Institut National de la Recherche Agronomique (INRA) has developed a simulation model with the aim of building a spatial multi-agent simulator capable of conducting a Acta Sci.…”