Long-term priority effects among insects and fungi colonizing decaying wood

Abstract

Summary1. Priority effects have been hypothesized to have long-lasting impact on community structure in natural ecosystems. Long-term studies of priority effects in natural ecosystems are however sparse, especially in terrestrial ecosystems. 2. Wood decay is a slow process involving a high diversity of insect and fungus species. Species interactions that drive change in communities of insects and fungi during wood decay are poorly understood because of a lack of sufficient long-term studies. 3. In this paper, we followed the colonization and succession of wood-living insects and fungi on cut trees during 15 years, from tree death and onwards, in a boreal forest landscape. We test the long-term priority effects hypothesis that the identity and abundance of species that colonize first affect the colonization success of later-arriving species. We also hypothesize that species interact in both facilitative and inhibitory ways, which ultimately affect habitat quality for a red-listed late-succession beetle species. 4. Possible causal associations between species were explored by path analysis. The results indicate that one bark beetle species, Hylurgops palliatus, and one wood-borer species, Monochamus sutor, which colonized the wood during the first year after cutting, influenced the occurrence of a rare, wood-living beetle, Peltis grossa, that started to emerge from the stumps about 10 years later. The positive effects of Hylurgops palliatus and negative effects of M. sutor were largely mediated through the wood-decaying fungus species Fomitopsis pinicola. 5. The study shows that variable priority effects may have long-lasting impact on community assembly in decaying wood. The study also exemplifies new possibilities for managing populations of threatened species by exploring links between early, well-understood species guilds and late, more poorly understood species guilds.

Priority effects of early successional insects influence late successional fungi in dead wood

“…Patch continuity is very long in the dead wood system and both our correlative field study and that of Weslien et al. (2011) indicate that priority effects from early colonizing wood‐living beetles have a long‐lasting and strong influence on the establishment of wood‐decay fungi. Experimental or comparative studies including a wide range of short‐lived and long‐lived habitats are needed to establish whether priority effects in heterotrophic communities are modulated by patch continuity.…”

“…For instance, Weslien et al. (2011) found that colonization by the wood‐boring beetle Hylurgops palliatus (Gyllenhal, 1813) in early succession had an indirect positive effect on the endangered beetle Peltis grossa (Linnaeus, 1758) in late succession of spruce dead wood. Thus, loss of H. palliatus from a region would presumably have a negative influence on P. grossa .…”

“…2011; Weslien et al. 2011). Priority effects of species arriving early can be positive or negative for the late successional species, leading to facilitative or inhibitory succession (Connell and Slatyer 1977).…”

“…To our knowledge, there has only been one previous study of long‐term priority effects in dead wood communities (Weslien et al. 2011). Weslien et al.…”

“…Weslien et al. (2011) showed that early colonizing wood‐boring beetles (Coleoptera) affect subsequent establishment of the common wood‐decay fungus the Red‐belt conk ( Fomitopsis pinicola (Sw.: Fr.) P.…”