Track 1-1-2: Biodiversity, Growth and Management of Temperate and Mediterranean Grasslands

Description

Mediterranean grasslands are a highly diverse and complex ecological resource of considerable economic and environmental importance. Herbaceous plant production that determines the carrying capacity of these grasslands for beef cattle husbandry is not only influenced by climatic factors, habitat characteristics, soil fertility and depth, but also by the stocking density and the nature of the grazing system (Gutman et al., 1999). The yearly Mediterranean pasture cycle is characterized by a temperate, winter-spring growing season and a hot, dormant, summer-autumn dry season. Consequently, pasture growth dynamics result in extremely low biomass availability at the beginning of the rainy season and abundant biomass at the peak of the growing season (Henkin et al., 1998). This is followed by a sharp reduction in amount and quality of the herbaceous vegetation caused by seed dispersal, desiccation, grazing and weathering during the hot and dry summer. Grazing pressure and the consequently highly variable availability and quality of the pasture vegetation determine the nutritional intake of the grazing animals as well the impacts on the growth dynamics of the pasture. High stocking densities interact with forage biomass production, consequently, the amount of standing biomass in the pasture decreases when stocking density increases above a moderate stocking rate. During maturation and seed development, heavy grazing can reduce the potential for re-growth in the following season while at the beginning of the growth season, heavy grazing can inhibit pasture growth to far below that required for adequate animal nutrition. Deferment of heavy stocking at the beginning of the growing season can prevent the fall of pasture production to a low stable equilibrium (Noy-Meir 1975; Gutman et al., 1999). However, with increasingly heavy stocking, deferment must be severely increased to prevent serious reduction of both the growth of the pasture and the nutrition of the grazing herd. The aim of the current study was to identify the productivity and sustainability of Mediterranean grassland under different stocking densities and timing of the grazing on a predominantly annual Mediterranean pasture. The present analysis is based on a long-term experiment (1994 - 2014).

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Range Dynamic and Sustainability of Mediterranean Grassland

Mediterranean grasslands are a highly diverse and complex ecological resource of considerable economic and environmental importance. Herbaceous plant production that determines the carrying capacity of these grasslands for beef cattle husbandry is not only influenced by climatic factors, habitat characteristics, soil fertility and depth, but also by the stocking density and the nature of the grazing system (Gutman et al., 1999). The yearly Mediterranean pasture cycle is characterized by a temperate, winter-spring growing season and a hot, dormant, summer-autumn dry season. Consequently, pasture growth dynamics result in extremely low biomass availability at the beginning of the rainy season and abundant biomass at the peak of the growing season (Henkin et al., 1998). This is followed by a sharp reduction in amount and quality of the herbaceous vegetation caused by seed dispersal, desiccation, grazing and weathering during the hot and dry summer. Grazing pressure and the consequently highly variable availability and quality of the pasture vegetation determine the nutritional intake of the grazing animals as well the impacts on the growth dynamics of the pasture. High stocking densities interact with forage biomass production, consequently, the amount of standing biomass in the pasture decreases when stocking density increases above a moderate stocking rate. During maturation and seed development, heavy grazing can reduce the potential for re-growth in the following season while at the beginning of the growth season, heavy grazing can inhibit pasture growth to far below that required for adequate animal nutrition. Deferment of heavy stocking at the beginning of the growing season can prevent the fall of pasture production to a low stable equilibrium (Noy-Meir 1975; Gutman et al., 1999). However, with increasingly heavy stocking, deferment must be severely increased to prevent serious reduction of both the growth of the pasture and the nutrition of the grazing herd. The aim of the current study was to identify the productivity and sustainability of Mediterranean grassland under different stocking densities and timing of the grazing on a predominantly annual Mediterranean pasture. The present analysis is based on a long-term experiment (1994 - 2014).