The choice of provenance for pedunculate oak influences associated biodiversity
Pedunculate oak is an important host tree for many insect species, including gall wasps. In a trial planting involving trees of Flemish, French and Danish origin, we studied the summer galls of nine gall wasp species over a five-year period.
For seven species, the numbers were significantly lower on the French origin trees than on the Danish and Flemish ones. Furthermore, regardless of origin, gall wasps were more common on trees that budded later in the spring. Some species also responded to tree size and leaf colour.
These results demonstrate that the choice of source material for forest plantings is relevant not only to growth and climate resilience, but also to the biodiversity that depends on these trees. The choice of provenance therefore deserves attention in forest management, planting guidelines and adaptation strategies in the context of climate change. Further monitoring is needed to determine how these insect communities will evolve in the longer term.
Kristine Vander Mijnsbrugge, Kevin Maebe
Image above: Cynips longiventris: (photo INBO)