In the absence of native forests, non-native plantation forests have been identified as having an important function in conserving native biodiversity world-wide, including fungal biodiversity. The non-native tree species Sitka spruce (Picea sitchensis (Bong.) Carrière) is now the most abundant tree species in forests in Ireland and Britain, and these forests have been the focus of recent research into their ability to conserve native biodiversity. We conducted an analysis using data from macrofungal surveys from Sitka spruce forests in its native (Vancouver Island, Canada) and non-native (Ireland and Britain) range. Also included in all analyses were data for macrofungal diversity from other native tree species forests in each of the three regions. A total of 630 macrofungal species from seven forest types were analyzed, including 122, 247, and 70 species from Irish, British, and Vancouver Island Sitka spruce forests, respectively. In all three regions, notwithstanding differences in the ages of the sites surveyed in each region, the Sitka spruce forests were found to have species richness similar to that of the other forests types investigated. The communities of the Sitka spruce forests were clearly different in each of the regions, with only 17 species shared among Sitka spruce forests in all three regions. Overall, we found that Sitka spruce plantations in Ireland and Britain could provide a complementary ecosystem for native macrofungi, acting as a suitable forest type for many macrofungi in the absence of native forests. By encouraging the development of old-growth conditions in some plantations, along with the conservation of already existing seminatural forests in Britain and Ireland, we believe the best situation for macrofungal conservation can be achieved.
Lessons from native spruce forests in Alaska: managing Sitka spruce plantations worldwide to benefit biodiversity and ecosystem services