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| Introduced mammalian herbivores can negatively affect ecosystem structure and function if
they introduce a novel disturbance to an ecosystem. For example, belowground foraging herbivores that
bioturbate the soil, may alter process rates and community composition in ecosystems that lack native
belowground mammalian foragers. Wild boar (Sus scrofa) disturb the soil system and plant community via
their rooting behavior in their native range. Given their size and the numbers in their populations, this
disturbance can be significant in forested ecosystems. Recently, wild boar were introduced to Patagonian
forests lacking native mammalian herbivores that forage belowground. To explore how introduced wild
boar might alter forested ecosystems, we conducted a large-scale wild boar exclusion experiment in three
different forest types (Austroducedrus chilensisforest, Nothofagus dombeyi forest, and shrublands). Wild boar
presence altered plant composition and structure, reducing plant biomass 3.8-fold and decreasing both
grass and herb cover relative to areas where wild boar were excluded. Decomposition rates and soil
compaction also declined by 5% in areas where boar had access; however, rooting had no effect on soil
nutrient stocks and cycling. Interestingly, there were no differences in wild boar impacts on different forest
types. We found that after 3-years of exclusion, belowground foraging by wild boar had a larger impact on
plant community structure and biomass than it did on soil nutrient processes. | |
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