Over the past decades, mainly due to the agricultural policies of the EU, there has been a sharp increase in the number of sheep and semi-wild goats on the island of Samothraki. Overgrazing, coupled with the steepness of the terrain, has led to excessive soil erosion, thus posing a major threat to conservation efforts. As a result, a series of concerted research projects have been initiated, and one of the current priorities is to explore ways to increase plant productivity and grazing tolerance of overgrazed lands.
For this purpose, a pilot project is currently underway in collaboration with the University of Lisbon, its spin-off Terraprima, and local farmers, in order to assess the effectiveness of Sown Biodiverse Pastures (SBP) on Samothraki. The SBP system is based on sowing up to 20 species/varieties of legumes and grasses that are self-maintained for at least 10 years, with all used species native to the island. The legumes, being ‘natural factories’ of nitrogen, minimize the need for synthetic fertilisers.
After carefully assessing local soil and climatic characteristics, we are currently testing several seed mixtures that improve productivity and soil quality, while also being more resistant to grazing. Α first set of 13 experimental plots have been selected for application, and results to date are promising. In a second stage, a further set of plots, in olive groves and in very erosion-prone areas, will be tested.
Current findings and advice for future action
Results so far indicate that permanent, rather than annual, SBP present great potential for the island of Samothraki. Field trials indicated that if care is taken during soil preparation and actual sowing, establishment of SBP is successful. When sowing took place in the period of October-November, field trials indicated a large seed production in May of various sown species. In the first year after sowing, legume abundance in the field trials ranged from 33% to 63%, and the key species behind the rationale of permanent SBP, Trifolium subterranean, thrived well in all field trials. In addition, productivity in the permanent SBP was on average 30% higher as compared to conventional agricultural practices.
Overall, Samothraki provides excellent conditions for the installation of sown biodiverse permanent pastures and further extending the areas where SBP are sown can have multiple benefits, not only for farmers’ economic performance, but also for the pastures’ role in biodiversity conservation, and their high ecological, cultural and aesthetic value. Besides combating soil erosion and increasing forage production, SBP can also contribute to the development of a label of ‘sustainable agricultural products’ that can be potentially extended to goat meat, cheese, honey, and liquors that are produced as a result of the good agricultural practices associated with this type of pasture.
You can watch a video of a visit to one of the sown bio-diverse pastures which took place in 2017, on the page of the 4th Summer School on Aquatic and Social Ecology during which the field trip took place.
Also ongoing is the Master thesis of Markus Löw (ongoing), Creation of a land use/land cover map for Samothraki, for 4 different points in the last 4 decades.