The composition of the arthropod predator community and associated cascading effects on the plant community explained 41% of variation in soil C retention among 15 old-fields across a human land use gradient. We also evaluated the potential for several other candidate factors to explain variation in soil C retention among fields, independent of among-field variation in the predator community. These included live plant biomass, insect herbivore community composition, soil arthropod decomposer community composition, degree of land use development around the fields, field age, and soil texture. None of these candidate variables significantly explained soil C retention among the fields. The study offers a generalizable understanding of the pathways through which arthropod predator community composition can contribute to old-field ecosystem carbon storage.
The researchers used next generation sequencing of the DNA in soil from samples taken across the site that had a range of plantings between six and 10 years old.
The technique – high-throughput amplicon sequencing of environmental DNA (eDNA), otherwise known as eDNA metabarcoding – identifies and quantifies the different species of bacteria in a sample.
The researchers – students Nick Gellie and Jacob Mills, Dr Martin Breed and Professor Lowe – analysed soil samples at the restoration site at Mt Bold Reservoir in the Adelaide Hills, South Australia, and compared them with neighbouring wilderness areas as ‘reference sites’.
“We showed that the bacterial community of an old field which had been grazed for over 100 years had recovered to a state similar to the natural habitat following native plant revegetation – an amazing success story,” says Dr Breed, Research Fellow in the Environment Institute.
“A dramatic change in the bacterial community were observed after just eight years of revegetation. The bacterial communities in younger restoration sites were more similar to cleared sites, and older sites were more similar to the remnant patches of woodland.”
Revegetation rewilds the soil bacterial microbiome of an old field – Gellie – 2017 – Molecular Ecology – Wiley Online Library
Got Aphids? Plant onions or leeks, or chives…
Planet’s satellite network captures a lot more imagery than has typically been available, and on a more frequent basis – it can collect a new snapshot of every piece of land on Earth daily, via its network of 149 orbital satellites.
- At best one field saw a 2.5% change in %TOC over 5 years.
- Biggest increase came from not plowing.
- No longer bailing straw.