We don’t really know for sure (yet). Aboveground, we make sure we harvest after the flowering period, allowing the pollinators to have their feast, boosting all other sorts of insectivores (e.g. birds, bats, spiders). By harvesting rockrose on a rotational system, we end up with different heights and structural niches allowing a mosaic heterogeneity that is closely linked to higher biodiversity levels. Furthermore we do not harvest rockrose in the line of the trees in the agroforestry system, being a heaven for spiders with their beautiful webs. Furthermore, by having standing rockrose, even after harvest by coppicing, we maintain a protective layer for small mammals to thrive, ultimately to support the hunting of our beloved Iberian Lynx, that we were lucky to see twice in the last 3 years (sorry we can’t prove it… you have to believe us on this one!).
Belowground we are definitely sure that we are doing better that the regional business as usual where soil is turned over to kill rockrose for land to be eligible for Common Agricultural Policy, i.e. land having rockrose as a shrub is not considered to be in “Good Agricultural and Environmental Conditions” – the so called GAEC). Soil depletion processes are well known when turning the soil over, not only erosion and nutrient loss, but also biological activity (fungi, bacteria, mycorrhizae, etc) that gets hammered by oxidation and radiation, reducing the regulation function of soil biological control against unbalanced biota that may become a pest. We use a well-known proxy to assess our soil biodiversity levels: Organic matter content. By managing rockrose like we are managing we are transforming a landscape from a frequent 0.5% of soil organic matter (common in surrounding agricultural areas) towards higher levels. We are currently undergoing research where we took about 40 soil samples and we are finding organic matter levels increased by up to 10 fold (OM samples between 1 to 6%). We haven’t assessed directly the species inventory of different taxa, but we know from research that thy OM levels are a great proxy that indicate a regeneration of the soil we are aiming at.