Dr Cristian Navarro Waggershauser, researcher on the Endangered Landscapes & Seascapes Programme’s Advancing Restoration Knowledge project “Metabarcoding for Restoration”, takes us into the field in Portugal and Scotland. His work explores how DNA metabarcoding can uncover the hidden biodiversity of soils and what this means for ecosystem restoration.
Bending the curve of biodiversity loss depends on restoration efforts that are ambitious, sustained and measurable. Monitoring progress is essential, yet many schemes focus on what can be seen above ground – plants, birds or mammals – while overlooking the vast diversity hidden in the soil. Fungi, bacteria and invertebrates are key to ecosystem functioning, but we know relatively little about how they respond to restoration. This spring I set out on two field campaigns, one in Portugal and one in Scotland, to collect soil samples and explore how environmental DNA (eDNA) can fill these gaps.
Portugal: Rewilding with natural herbivory
The first stop was the Greater Côa Valley, where Rewilding Portugal is restoring natural processes and creating a wildlife corridor linking the Malcata mountains with the Douro valley. This Mediterranean landscape, shaped for centuries by grazing, is now undergoing change as land abandonment and fire risk open opportunities for biodiversity recovery. Semi-wild herds of Sorraia horses and Tauros cattle have been introduced to restore natural herbivory. At the same time, vultures, Bonelli’s eagle and even wolves are returning to the area.
I stayed at the local rewilding centre with volunteers and staff, and was guided by André Couto. The landscape was greener and wetter than I expected, not least because it rained most of the time I was there. Fieldwork meant crossing dense vegetation, occasionally startling the free-ranging Sorraia horses, and vice versa. Calm but imposing, they were a reminder of how rewilding is reshaping this landscape. Alongside the horses, vultures, red kites and other raptors were frequent companions overhead.
Scotland: Forest expansion in Cairngorms Connect
The second campaign took place closer to home, in Scotland, within the Cairngorms Connect partnership area. Here, restoration takes a different shape: reducing grazing pressure and expanding native pine and broadleaf forests across the western slopes of the Cairngorms plateau.
I know this landscape well, having spent much time in the area, though the monitoring sites chosen for this survey introduced me to new corners of the forest, especially up the steep slopes of Invereshie. Ironically, while it rained most of my time in the Côa Valley, I had beautiful sunshine throughout my time in Scotland. The wildlife was less dramatic than in Portugal – though a tick bite reminded me of the realities of fieldwork – but the scenery was as rewarding as ever.
Sampling days here were straightforward, supported by Cairngorms Connect staff member Ellie Dimambro-Denson. Together we prepared the samples using traditional soil mixing techniques and added to the project’s growing collection, which builds on ongoing monitoring efforts by Cairngorms Connect and underpins restoration in the area.
What we are doing
Across the two landscapes, we collected 120 samples spread over gradients of restoration. In Scotland, we sampled across different forest states, from upland heath outside the treeline to old growth stands. This will allow us to map how below-ground communities shift as forests expand.
In Portugal, we worked across two experiments run by Rewilding Portugal: exclusion fences that test the effects of reintroducing natural grazing patterns, and a recently restored mining site next to older regenerating woodlands.
Using eDNA metabarcoding, these samples will help fill monitoring gaps, advance our understanding of below-ground communities, and provide new insights into how soils respond as restoration progresses.
To find out more about Metabarcoding for Restoration, visit their project page. This article was written by Dr Cristian Navarro Waggershauser, researcher at the University of Inverness Institute for Biodiversity and Freshwater Conservation.
