Dwarf Mistletoe and Drought Contribute to Growth Decline, Dieback and Mortality of Junipers

Rising temperatures and aridification, combined with the stressing effect of some hemiparasitic plants such as mistletoes, may contribute to reduce vigour growth trees shrubs leading dieback increasing mortality. This has been rarely explored in pioneer junipers, which are assumed be more drought tolerant than coexisting trees. To test these ideas, we reconstructed radial patterns common junipers (Juniperus communis L.) different crown cover infestation degree by dwarf mistletoe (Arceuthobium oxycedri (DC.) M. Bieb.) two sites contrasting aspect water availability located north-eastern Spain. We used dendrochronology study response junipers’ climatic factors (temperature, precipitation, soil moisture), an index severity, infestation. Juniper was constrained elevated low precipitation during growing season. Infestation contributed a short-term decline junipers. The interaction between summer high juniper growth, particularly north-oriented wetter site, where hosts presented higher rates wet periods. negative impact on overrides effects due Aridification could trigger mortality slowing down successional dynamics delaying shrub encroachment into former croplands grasslands.