"Wood Decomposition in Poorly-drained Forested Wetland Soils: How Impor" by Mary Beth Adams, Chris Miller et al.
 

Wood Decomposition in Poorly-drained Forested Wetland Soils: How Important are Termites?

Document Type

Article

Publication Date

5-2025

Department

College of Forest Resources and Environmental Science

Abstract

Termites are important wood decomposers in tropical and sub-tropical forest ecosystems, but less is known about termite activity in temperate forests, especially poorly-drained wetlands. Therefore, we carried out a 5-year study to assess the effects of a seasonally-variable water table on wood decomposition by termites. The study was carried out on three forested wetland sites on the Atlantic Coastal Plain of the US where the water table was: 1) only in the mineral soil, 2) at the soil surface for 3.7 months/year, and 3) at the soil surface for 5.7 months/year, and on an adjacent drier upland forest. We used wood stakes of aspen (Populus tremuloides Michx.), red maple (Acer rubrum L.) and loblolly pine (Pinus taeda L.), which were placed on the surface litter, at the litter-mineral soil interface, and in mineral soil, and sampled annually. Stake mass loss was used to measure the effect of termites on wood decomposition.

Wood decomposition and termite activity on the three wetland sites was controlled by soil depth to the water table, being greatest where the water table was rarely above the mineral soil surface, and least where the litter layer was inundated the longest. At the end of 5 years the effect of termites on wood stake mass loss was highest at the litter surface (51%), and lowest in the mineral soil (30%) where microbial decay dominated. However, small differences in surface elevation can affect termite activity and wood mass loss in the mineral soil. Termites likely fed on stakes during drier summer months, often only on the stake surface, and favored aspen, less for red maple, and least for pine. Termites dominated decomposition in the upland. Stake mass loss was lowest on the litter surface but exceeded 85% at all three soil locations. In contrast to the wetlands, termites showed little difference in wood stake feeding preference. This effect of soil water content on termite feeding preference has not been observed elsewhere.

Our study suggests that altered precipitation amounts projected in future climate scenarios could have a greater effect than temperature on wood decomposition by termites in poorly-drained wetland ecosystems. Much more information is needed on termite activities in mineral soil across different climate regimes, and what factors control termite preference for wood species in soils with different water regimes.

Publication Title

Soil Biology and Biochemistry

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