Abstract
BackgroundClimate extremes are likely to become more common in the future and are expected to change ecosystem processes and functions. As important consumers of seeds in forests, rodents are likely to affect forest regeneration following an extreme weather event. In April 2015, we began a field experiment after an extreme snowfall event in January 2015 in a primary forest that was > 300 years old. The heavy snow broke many tree limbs, which presumably reduced the numbers of seeds produced. Two treatments (rodent exclusion and rodent access) were established in the forest, in which rodent exclusion were achieved by placing stainlessness nets around the plot borders. Plant abundance, plant species richness, soil properties, soil microbial community composition, basal and substrate-induced respiration were determined in December 2017.ResultsPlant abundance and species richness significantly increased, but soil microbial biomass decreased with rodent exclusion. Urease activity and soil basal respiration also significantly decreased with rodent exclusion. Most other soil properties, however, were unaffected by rodent exclusion. The relative effects of multiple predictors of basal respiration were mainly explained by the composition of the soil microbial community.ConclusionsAfter a heavy snowfall in an old-growth forest, exclusion of rodents increased plant regeneration and reduced microbial biomass and soil basal respiration. The main factor associated with the reduction in soil basal respiration was the change in the composition of the soil microbial community. These findings suggest that after a heavy snowfall, rodents may interfere with forest regeneration by directly reducing plant diversity and abundance but may enhance carbon retention by indirectly altering the soil microbial community.
Highlights
Forests cover about 4 billion ha worldwide and provide important ecosystem goods and functions (Fei et al 2018; Jactel et al 2018; Keenan et al 2015)
We found that rodent exclusion significantly decreased soil microbial biomass, which was inconsistent with our hypothesis and with previous findings that increases in plant diversity increased soil microbial biomass (Jing et al 2015; Lange et al 2015)
As we suggested earlier in the Discussion that heavy snowfall is likely to increase the percentage of seeds consumed by rodents, such that the effects of rodents on plant regeneration would differ depending on whether or not exclusion occurred after a heavy snowfall
Summary
Forests cover about 4 billion ha worldwide and provide important ecosystem goods and functions (Fei et al 2018; Jactel et al 2018; Keenan et al 2015). Extreme snowfall events are likely to have substantial effects on forest ecosystems (Ashley et al 2020; Zhao et al 2016). The snowpack in winter can change soil carbon emission by affecting soil temperature and moisture (Contosta et al 2016). Consistent with the latter result, a meta-analysis revealed that an increase in snowpack depth can increase soil respiration and microbial biomass by increasing soil temperature and water content (Li et al 2016). Climate extremes are likely to become more common in the future and are expected to change ecosystem processes and functions. Plant species richness, soil properties, soil microbial community composition, basal and substrate-induced respiration were determined in December 2017
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