The installation of minirhizotrons at Ainsdale Dune Slacks has allowed the team at Loughborough University to understand how plant communities change in dune slacks over time as a result of grazing.
[Above photo credit: Ellen Fry]
Ainsdale Dune Slacks are a part of the Sefton Coast near Southport. The Sefton sand dune system on the north-west coast of England is the largest dune system in the country. It is home to a high number of rare and specialised plant species as well as nationally protected wildlife. The dunes are a dynamic landscape shaped by the wind. However, the stabilisation of the slacks by vegetation is an undesirable outcome. Therefore, the site is grazed by cattle and sheep in a carefully rotated pattern.
To understand the effects of mammal grazing on the slacks, a long-term grazing experiment was set up in 1974 to determine how rabbit grazing impacts vegetation composition. In 1991, these small plots were enclosed in a sheep-proof fence creating a nested design with grazed control plots outside. The data obtained so far has indicated that rabbits and sheep halt succession in dune slacks as the ungrazed plots develop into a scrub community. Further information on root growth could allow an insight into seasonal growth patterns as well as below-ground interactions.
The team at Loughborough University received an ECT small grant which was been used to build minirhizotrons based on a design from a team at the University of Leeds (Arnaud et al., 2019). These are tubes of clear Perspex that were installed in the soil at an angle to view the below-ground portion of the plants. Using a small endoscope camera and a 3D printed apparatus, the team at Loughborough University are able to return annually and measure the same plant roots.
Minirhizotron installed. The tube is clear Perspex, and has been stoppered against influxes of rain. These will be visited periodically over the next five years to monitor root growth in situ. Photo credit: Jonathan Millett.
Setup and usage of minirhizotrons, image taken with kind permission from Arnaud et al. (2019) Creative Commons Attribution 4.0 International License).
This provides a time integrated, non-invasive estimation of root growth, and is an alternative method to digging up roots destructively which is not possible in long-term plots. By integrating the data with above-ground vegetation characteristics, the team can begin to understand how plant communities change in dune slacks over time. While this method has been used in many habitats, this is the first example it is being used on dune slacks.
