Summary Additional biological evidence is presented for the alteration of biogeochemical cycles by human activities. The leaf δ 15 N and the concentrations of nutrients in herbarium specimens of 24 species of vascular plants and 3 species of bryophytes collected in northern and eastern regions of Spain have substantially changed throughout the XX century. In the second half of the century, when anthropogenic nitrogen fixation...

Summary Leaf mineral concentrations of co‐occurring Erica arborea, Juniperus communis and Myrtus communis were measured at bimonthly intervals throughout a year in a natural CO 2 spring and in a nearby control site with similar soil chemistry in a Mediterranean environment. There were different responses to the elevated [CO 2 ] ( c . 700 μL L −1 ) of the spring site plants depending on the element and the species. In the CO 2...