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Research article2024Peer reviewedOpen access

Forest structure and heterogeneity increase diversity and alter composition of host-parasitoid networks

Rappa, Nolan J.; Staab, Michael; Ruppert, Laura-Sophia; Frey, Julian; Mello, Marco A. R.; Klein, Alexandra-Maria

Abstract

Antagonistic host-parasitoid interactions can be quantified using bipartite and metanetworks, which have the potential to reveal how habitat structural elements relate to this important ecosystem function.Here, we analysed the host-parasitoid interactions of cavity-nesting bees and wasps, as well as their abundance, diversity and species richness with forest structural elements from 127 forest research plots in southwestern Germany.We found that parasitoid abundance, diversity and species richness all increase with host abundance, a potential mediator between parasitoids and forest structure. Both parasitoid abundance and diversity increased with stand structural complexity, possibly mediated by the abundance of hosts. In addition, parasitoid abundance increased with increasing standing deadwood and herb cover.The bipartite networks of host-parasitoid interactions showed higher connectance with increasing standing deadwood, herb cover and host abundance. Analyses of interactions within the host-parasitoid metanetwork revealed that increasing host abundance and decreasing canopy cover diversify the suites of interactions present at the plot level.These results demonstrate that forest structural elements can improve the stability and resilience of host-parasitoid networks by promoting parasitoids and diversifying interactions in ecological networks.Cavity-nesting bees and wasps and their associated parasitoids rely on forest structural elements such as deadwood. Host-parasitoid interaction networks can reveal how these forest structures can support this important ecosystem function.Here, we sample cavity-nesting bee wasps and their parasitoids from 127 forest research sites, along with gradients of amounts of forest structural elements.We found that increasing amounts of forest structural elements increased the diversity of parasitoids and altered species composition, partly via increasing host abundance. In addition, canopy openness diversified suites of host-parasitoid interactions.image

Keywords

ecological networks; ecosystem functions; forest conservation; Hymenoptera; remote sensing

Published in

Ecological Entomology
2024, Volume: 49, number: 2, pages: 257-271