Ansaat artenreicher Samenmischungen in künstliche Störstellen: eine vielversprechende Methode zur Erhöhung der Diversität im artenarmen Grünland

Orsolya Valkó, Balázs Deák, Péter Török, Anita Kirmer, Sabine Tischew, András Kelemen, Katalin Tóth, Tamás Miglécz, Szilvia Radócz, Judit Sonkoly, Edina Tóth, Réka Kiss (+2 others)
Halting the loss of grassland biodiversity and restoring degraded ecosystems are high priority tasks in the EU Biodiversity Strategy. Sowing low-diversity seed mixtures is widely used in grassland restoration because of its high predictability and fast, promising results. Generally, the sown perennial grasses establish within a few years and form a dense sward, which effectively suppresses weeds. Unfortunately, these grasslands are often species-poor because the sown grasses hamper the
more » ... hamper the colonisation of target grassland forbs. Our aim was to test a novel approach to increase the diversity of species-poor grasslands. We selected eight 8-year-old grasslands restored by low-diversity seed sowing where we created 32 establishment gaps by breaking up the grass sward and sowing a high-diversity seed mixture (35 native species). Altogether, we established three grazed gaps (1 m × 1 m, 2 m × 2 m and 4 m × 4 m) and one fenced gap (4 m × 4 m) per site and monitored the presence and abundance of sown and non-sown species within a time frame of two years. We asked the following questions: (1) Which target species establish most successfully? (2) What is the effect of establishment gap size on the establishment success of target species and weeds? (3) What is the effect of management (grazed versus not managed) on the species composition of the establishment gaps? Our results showed that by creating establishment gaps and sowing diverse seed mixtures, we were able to overcome microsite and propagule limitation, successfully introducing target species into the species-poor grasslands. We found that all sown species established in the gaps, and the majority of the species maintained or even increased their first-year cover in the second year. Smaller gaps were characterised by lower cover of sown species and a quite stochastic development compared to the larger ones. Weed cover was moderate in the first year and decreased significantly in the second year, regardless of gap size. Therefore, in restoration practice, the use of larg [...]
doi:10.14471/2016.36.020 fatcat:555jrsaevjbxvaagsswju4ebye