Reintroduction of rare plant species on arable fields: Challenges and opportunities
Mit Prof. Dr. Johannes Kollmann, TU München
In the past decades the vegetation of arable fields has been largely depleted with negative effects on biodiversity. Thus, preservation of remnant populations is no longer sufficient, while the introduction of autochthonous seeds is a promising measure to promote threatened plant species and to restore agro-ecosystems. However, knowledge is scarce about the most reliable introduction methods and suitable establishment conditions for sown species. Thus, the Chair of Restoration Ecology in collaboration with various partners has investigated this topic in a series of experiments in climate chambers, greenhouses and arable fields. Topics covered include the choice of suitable provenances, sowning densities, cover crops and management. As target variables we have investigated the effects on plant fitness, seed bank and population dynamics, and on ecosystem services of rare arable plants. Overall, differentiation of source populations is weak, establishment successful in many species and different crop rotations, and negative effects on yield relatively low. However, dense cover crops (as clover grass) suppress establishment of the target species and re-introduction of arable plants in conventional agriculture is still a challenge. The talk offers a synthesis of these projects including potential applications and perspectives for future research.