Troublesome plants in species-rich grasslands: can we maintain the toxic plant Carex brevicollis and alleviate its risk to livestock?

摘要

Carex brevicollis (DC in Lam. & DC) is a sedge naturally distributed on limestone, species-rich grasslands in the central and southern mountains of Europe. In areas where the species is abundant, frequent abortions associated with its consumption occur in pregnant sheep, cows and mares. Published studies indicate a high content of toxic alkaloids in C. brevicollis leaves. The toxicosis has led some farmers to the abandonment of grazing areas and, in some cases, to the controversial demand of measuresfor removing the species from grasslands. In order to ensure its maintenance and alleviate the risk to livestock, this research focused on 1) the nature of the alkaloids, and 2) the grazing practices followed by farmers. Toxic alkaloids seemed to be produced by the plant, but their concentrations were highly enhanced by the occurrence of endophyte fungal infection. This result highlights the complexity of the interactions plant-fungus-mammals and encourages further research. Independently, some farm management strategies may be implemented to decrease the risk of abortions, including the avoidance of grazing frost-covered pastures, the supplementation at starvation periods and the maintenance of the offspring with the herd during the summer grazing period.