plant diversity effects on soil collembola in boreal forest
abstract
collembola are one of the most abundant soil fauna in terrestrial ecosystems. they play essential
roles in ecosystem processes like litter decomposition. ongoing biodiversity loss across taxa
harms the stability and resilience of ecosystems and therefore threatens our sustainable
development. recent evidence has shown that biodiversity loss negatively impacts ecosystem
processes and functions such as productivity, soil microbes, and the production of fine roots.
despite the critical importance of soil collembola, our understanding of the effects of plant
diversity on soil collembola remains uncertain. the purpose of this dissertation is first to
summarize previous studies and reveal the general response of collembola to plant species
diversity across ecosystems. the second objective is to test whether tree mixtures affect the
collembola community in young boreal forests and if these mixture effects change with water
conditions and stand ages.
in my first study, by conducting a meta-analysis of 623 paired observations of plant
mixtures and corresponding monocultures from 40 studies, i examined the effects of plant
mixtures on soil fauna abundance and diversity across global terrestrial ecosystems and
summarized consistent responses of soil fauna to plant species diversity across soil depths,
ecosystem types, and climate conditions. i found that the diversity of soil fauna was on average
10% greater in plant mixtures than expected from corresponding monocultures. in contrast, the
abundance of fauna did not respond to plant mixtures. importantly, plant mixture effects on both
soil fauna abundance and diversity significantly increased with plant species richness in
mixtures. moreover, the effects of plant mixtures on soil fauna abundance increased over time in
diverse species mixtures. [...]