Data from: White-tailed deer (Odocoileus virginianus) exclusion shifts soil carbon dynamics in mature oak-dominated and hemlock-dominated forest stands

While the direct effects of white-tailed deer (Odocoileus virginianus) on
vegetation have been intensively studied, less is known about the indirect
and interactive effects of herbivory on lower trophic levels, such as soil
microbes and their processing of carbon pools. We explored how carbon
dynamics shift with release from over-browsing by white-tailed deer in two
mature stands of oak and hemlock trees. We measured soil carbon pools
(e.g., soil organic matter, carbon stocks, litter biomass, and litter
stabilization) and fluxes (e.g., soil respiration, methane uptake,
microbial substrate use, and litter decomposition) using a spatially
balanced survey design inside and outside two 24-year-old deer exclosures,
one in each forest stand. Soil carbon pools were higher inside the
exclosures than in deer-browsed plots in both forest stands, but the
effect of deer herbivory on fine-scale spatial patterning of soil carbon
pools and mean carbon fluxes varied by forest type. Release from deer
herbivory in the oak stand increased the patchiness of soil pools and led
to higher litter decomposition, soil respiration, and methane uptake
rates. Release from deer herbivory in the hemlock stand did not affect the
spatial structure of soil pools, had little effect on methane uptake, and
had negative effects on litter decomposition and soil respiration. These
differences may be due in part to the interactive effects of two
herbivores, deer and the hemlock woolly adelgid (Adelges tsugae), that
appear to be limiting regeneration and promoting the proliferation of
monodominant hay-scented fern (Dennstaedtia punctilobula) in the
hemlock-dominated stand. Our work suggests that future efforts consider
multiple zoogeochemical stressors simultaneously, in addition to variation
in environmental templates, to explain uncertainties in carbon pools and
fluxes in temperate forested ecosystems.