The effects of invasive earthworms on decomposition are little known, and the controls of their effect on decomposition may be different than those of microbes. Sugar maple–dominated forests previously devoid of earthworms in the western Great Lakes region (USA) exhibit different degrees of earthworm invasion, presenting a natural experiment to study its effects on litter decomposition. We hypothesized that litter decomposition would depend on the degree of earthworm invasion, the presence or absence of worms of differing sizes, and initial litter chemistry. We established an experiment using fine- and coarse-mesh litterbags (to allow access by different-sized worms) to study decomposition of 3 different litters in mixture under different degrees of earthworm invasion in 12 Minnesota sites. The effect of earthworm invasion degree on litter decomposition varied by identity of the litter, mesh size, and time of litter collection. Decomposition of Quercus rubra, the litter with the lowest initial calcium concentration and highest lignin:nitrogen, was not significantly influenced by earthworm invasion degree. In contrast, decomposition of Tilia americana, the litter with the highest calcium concentration and lowest lignin:nitrogen, was fastest in coarse-mesh litterbags. After 15 months the mass of the highest-quality litters was highest in the fine-mesh bags of heavily invaded plots, suggesting that microbially mediated decomposition slowed where earthworms had removed the forest floor.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.