In just a few cubic centimetres of soil you will find a complex web of life: predators and prey, destroyers and creators, who are helping to feed life itself.
The Marsden Fund has awarded University of Waikato’s Dr Andrew Barnes a Fast-Start grant to look into what lies beneath the ground in forest restoration projects, and the food web it entails. He has called the project Illuminating the dark side of restoration and it’s an area that really is in the dark in many ways. Dr Barnes says it’s an unexplored frontier. “We know alot about some very specific things down there, but we’re still actually in the dark about how the system works as a whole. It’s a massive area we really need to know a lot more about.”
The inspiration for the research came from the People Cities and Nature project. That’s an interdisciplinary research programme with six projects across New Zealand that are working towards restoring indigenous biodiversity in urban environments, lead by University of Waikato’s Professor Bruce Clarkson. Dr Barnes says the accessibility of the project attracted him. “Unlike many other restoration projects around the world it is completely focused in urban centres, so they’re environments which are directly open to everyday people, and are the majority of nature we see in our day to day lives.”
There are research sites in nine cities around the country, from Invercargill north to Tauranga. They’ve been restored by different organizations over a range of different times, so offer a lot of variety as essentially big laboratories. They’re being used to find out what restoration projects work, and why.
Dr Barnes says the main focus had been above ground, so the chance to look at how those factors are playing out in the soil was golden. He’ll be taking soil samples from the various sites, and finding out what soil biota is there - the biodiversity below ground. He’ll then extract the organisms from the soil. Dr Barnes says they have a general idea of what is down there - microbes, insects, mites, springtails. “But we still lack a lot of knowledge about which organisms are living in the soil, and whether or not there are any differences depending on the age of the forest.”
After the initial fact finding, the research will look for patterns in the way forests restore over time, and the way food-webs develop.. “Food-webs describe how the different species interact with each other through feeding. Which forms a kind of architecture so we can say whether the webs are becoming more complex over time. If they are becoming more complex does it mean they’re also becoming more stable? That’s important because we’re facing more stressors such as climate change, land-use intensification, and pollution. If these food webs are becoming more complex we may be able to see if they can withstand the increasing pressures of the future.”
While many of the organism in soil are workers, breaking down nutrients to feed plants, Dr Barnes says one of the fascinating things is that every trophic level is represented. If you want to know the big predators that lie beneath, he points to things like carnivorous mites. “You have centipedes which run down earthworm burrows. Many juvenile ground spiders will use tunnels to go hunting for their prey. There are a lot of things down there eating everything else.”
Other researchers involved in the project are: Chris Lusk (University of Waikato), Bruce Clarkson (University of Waikato) and Nico Eisenhauer (Leipzig University, Germany).