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University of Michigan Biological Station

The University of Michigan Biological Station (UMBS) was founded in 1909.

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Predicting changes in carbon cycling services provided by soil arthropods

Terrestrial
Vegetation
Project Abstract: 
Project objectives: (A) Initiate the first stage of an international collaboration wherein we will investigate the impact of induced forest disturbance on arthropod biomass and diversity. (B) Assess the relative influence of changes in forest ecosystem composition, function, and structure on the regulation of soil arthropod biomass and diversity. (C) Quantify the contribution of soil arthropods to carbon cycling and storage in temperate forests. (D) Develop predictive models linking disturbance, arthropod biomass and diversity and carbon cycling across North America’s temperate forests Project description: Forest disturbance occurring aboveground can trickle down to reshape belowground communities, which play a crucial role in decomposition and carbon cycling. A large fraction of the world’s organic matter on land is stored in soils, which stores ~1500 Gt carbon, roughly equivalent to all the carbon stored in the vegetation (~560 Gt) and atmosphere (~750 Gt) combined. Changes in decomposer communities, comprising arthropods and microbes, can lead to changes in rates of carbon cycling and sequestration. Ants alone have a combined biomass equivalent to that of all mammals and birds in the world. With an estimated ~12 Mt of dry carbon stored into their biomass, ants and other soil arthropods can clearly help buffer or exacerbate the impact of disturbance on the cycling and storage of nutrients in terrestrial ecosystems. Nevertheless, the contribution of soil arthropods to nutrient cycling remains poorly documented and often ignored in biogeochemical models. Dr Gough’s team has access to data on forest productivity, tree species composition, forest structure, and soil respiration, chemistry, and microclimate, all of which will be instrumental to fulfill our research objectives. All these data are available from 2008-2021 and will be available until at least 2026. Dr Lessard’s research group will bring expertise in the sampling and identification of soil organisms, as well as in the statistical analyses of biodiversity data. In 2023, a student from Concordia University will sample arthropods in disturbed and undisturbed forest stands using standardized sampling protocols we previously developed. They will use a combination of pitfall traps and leaf-litter extraction. They will then proceed to estimating insect biomass, density, and diversity in relation to forest productivity, tree species composition, forest structure, and soil respiration, chemistry, and microclimate.
Investigators: 
jlessa
Associates: 
cmgough
Status of Research Project: 
Active
Years Active: 
2023 to 2024
Research sites: 
FoRTE Disturbance Plots
Methods: 
We will take advantage of the FoRTE experimental set up to assess the influence of disturbance severity (0, 45, 65 or 85%) and type (top-down vs. bottom-up) on the abundance, biomass and diversity of soil arthropods. Severity levels are replicated 4 times (4 plots) and types are replicated 16 times (16 half-plots). To get a comprehensive estimate of soil community structure, three different sampling techniques will be applied to each experimental plot: pitfall traps, leaf-litter extraction and soil core extraction. Arthropod sampling will take place in the 1m buffer zone around each plot. In the buffer zone of each plot, a total of 6 pitfall traps, 2 leaf-litter samples and 4 soil cores will be extracted. This means that in each half-plot, a total of 3 pitfall traps, 1 leaf-litter sample and 2 soil cores will be extracted. Sampling will be conducted four times throughout the summer, once each month, on warm and sunny days. Given the number of plots (n=16) and sampling periods (n=4), a total of 384 traps (6x16x4), 128 leaf-litter samples (2x16x4) and 256 soil cores will be collected during summer 2023. Pitfall traps: Each pitfall trap will be a Freshware® propylene container (11.43 cm top diameter, 8.89 cm bottom diameter, 7.62 cm deep, 473.18 mL in volume). We will dig in pitfall traps, flushed with ground surface. We will place the pitfall traps with a lid a week before capturing organisms to minimize digging-in effects . We will then remove the lid, add propylene glycol to the containers and capture organisms for 72 hours. After 72 hours, we will transfer the arthropods in a jar containing 70% ethanol. Leaf-litter samples: Each leaf-litter sample will be a 0.25m x 0.25m quadrat. All leaf litter and small twigs within the quadrat will be taken avoiding to grab the dead organic matter layer, and then transferred into a litter sifter. Following sifting, the core debris remaining in the sifter will be returned to the forest floor, where they were originally collected. Leaf-litter samples collected at different periods during the summer will all be taken within the same 1m x 1m quadrat. Soil cores: each soil core will be extracted by inserting a PVC pipe (5 cm diameter, 10 cm depth) to extract the O and BE horizons.