Climate change threatens on endangered relict Serbian spruce

The increase in length and severity of drought events predicted for South-Eastern Europe are expected to engender important changes to remaining native forests. To make informed management decisions promoting their conservation, it is important to better understand their responses to climate and environmental disturbances.
In this study, we analyze growth responses over a network of 15 sites of Serbian spruce (Picea omorika), an endemic relict conifer species of the Balkan region — with a natural range restricted to the canyon of the Drina river at the border between Serbia and Bosnia Herzegovina — that has already shown signs of decline and dieback likely induced by increasing temperature and drought.
Tree-ring analyses spanning the common period from 1974 to 2016 have shown a strong growth reduction and highlighted an increasing negative growth response to summer drought over the last 30–40 years. The strength of the response differed among individuals and sites, where younger trees and those growing at lower altitude suffered more from drought.
Management practices oriented at reducing drought impact, such as thinning to reduce competition for water resources and enhance survival of seedlings, together with assisted natural regeneration and migration to more suitable habitats, are recommended for the conservation of this relict species. The measures are even more necessary considering that this species is more vulnerable than others due to its weak capacity to naturally regenerate and compete.