Negative effects of global change on seed viability of juniper

Knowledge about the interacting effects of various global-change drivers on sexual reproduction of plants, one of their key mechanisms to cope with change, is limited. Gruwez et al. study common juniper (Juniperus communis), a poorly regenerating and hence threatened species, to determine the impact of various factors associated with global change on key stages in reproduction. They find that negative effects of increasing temperature and atmospheric depositions on seeds mostly became visible after embryo development, when seeds are ripe and ready for dispersal. However, damaging influences begin during the development of the gamethophytes and around the fertilization period. They suggest that the failure of natural regeneration in many European juniper populations may be attributable to climate warming as well as high atmospheric deposition of nitrogen and sulphur.