Force-up the peat!: Impact of water table increase on peat meadow soil fauna communities

 

Background

The meadow landscape surrounding Amsterdam is rich in peat soil and has a high biodiversity value. One of the greatest challenges we face in the preservation of these meadows is peat oxidation. Low water table that allow farmer early excess on the field in early spring results in the layer of peat exposed to air. The resulting lift of anaerobic conditions gives many decomposers, especially fungi and bacteria, the change to degrade peat, followed by soil subsidence and an increase in CO2 emission to the atmosphere. Land subsidence has potentially strong impacts on regional water quality (due to salinization) and discharge of excess water after high precipitation events (due to less time to discharge water at low tide in the Wadden Sea). To hold peat degradation to a stop an increase in the water table is a logical step. Landschap Noord-Holland, a society that manages natural peat meadow areas, has recently started with experiment to rise the water table using flooded ditches.

Soil fauna are sensitive to changes in water content. Given their importance in nutrient dynamics, due to grazing of microbes and soil structure modification by digging through soil, it is necessary that we know how they respond to this chnage in water tables. So far, using trait-based approaches, we have been able to predict species response to an increase in soil drought using the trait drought tolerance. However, we do not know if we can also predict the opposite, the reaction of soil fauna communities to high soil water content, using flooding tolerance. In this project, which is in cooperation with Landschap Noord-Holland, we would like to (i) measure soil fauna community composition across transects running perpendicular from the border of flooded ditches to drier parts of peat meadows, and (ii) use species-specific traits (such as body size, tolerance, vertical stratification) to understand shifts in species composition.

Approach

This MSc project is a combination of field work conducted at the experimental site Ilperveld of Landschap Noord-Holland near Amsterdam and laboratory work (soil variables, soil fauna extraction and identification). Remaining work (reading, writing, analysis) can be done at home or at the VU if possible. It might be that a part of the laboratory work can be done at the experimental site in Ilperdam. There is no back-up data available if due to the Covid-crisis it is not possible to perform lab work.

You will learn:

  • how to plan and execute a field ecological survey
  • how to extract and identify the most important soil fauna groups
  • how to measure soil physico-chemical variables (pH, water content, organic matter)
  • how to apply trait-based approaches to understand the reaction of soil fauna communities
  • writing a report, in the form of a scientific article. Depending on the results a small paper in the Dutch journal De Levende Natuur is a possibility.
  • There are no specific skills required.

The timing of this project is open to discussion. You can start in the usual period January/February but if you want to start later (or sooner) that is also possible (as long as it does not freeze).

Supervision and information

Interested? Contact Prof.dr. Matty P. Berg
E-mail: m.p.berg@vu.nl
M: 06 – 12530372