Serbian spruce and climate change: Possible outcomes and conservation strategy

Serbian spruce is an old, relict and currently rare and endangered spruce species particularly susceptible to climate change that attracts a lot of attention in the academic community since its discovery in 1875. Today, Serbian spruce is limited to the area of ~100 km2 localized around the mid-course of the Drina River in the mountainous central Balkans, at the border of Republic of Serbia and Republic of Srpska, Bosnia and Herzegovina. Within this small area, ~30 remnant populations of various sizes are scattered at north-to-northwest orientated slopes of hills. Given the current state of Serbian spruce populations as well as extreme climate events and poor natural regeneration in this species, applied “do not touch” conservation approach is severely questioned, and some alternative protection and in situ and ex situ conservation actions have been put forward. In situ actions should involve: (1) facilitation of natural regeneration by selective removal of individual competitor trees, (2) assisted natural regeneration by planting high quality seedlings throughout the species current natural range or at nearby suitable sites, and (3) assisted natural regeneration by direct seeding. Although in situ actions may provide short-term persistence of Serbian spruce, ex situ actions, i.e., assisted migration, achieved by both assisted range expansion and assisted species migration, are inevitable, since it is very likely that Serbian spruce will disappear from its natural habitats in the near future due to the rapid climate change.