Seed production of a subalpine Festuca nigrescens-Agrostis capillaris semi-natural grassland in the eastern Italian Alps

Studying the seed production of semi-natural grasslands helps to understand their regeneration processes and to evaluate the possibility of collecting seed useful for ecological restoration. In a subalpine Festuca nigrescens-Agrostis capillaris meadow, the development of the main grasses' seed production and the standing seed yield at meadow maturity were studied. The inflorescence size was in the lower part of the variation range reported in previous studies. The seed viability was average to high and durable. The biological floret site utilization was mostly above 50%. With 458 fertile stems m(-2), the seeds produced (all seeds produced up to the time of the meadow maturity) by the main grasses were 21,000m(-2), of which 77% were of A. capillaris and 81% were viable. On a 3-year average, the standing seed yield (seeds present on the plants, i.e. produced minus shed seeds) at meadow maturity was 6953 seedsm(-2). Amount and composition of the produced seeds were affected mainly by the variability among years of the fertile stems density of the perennial grasses and the annual hemiparasite Rhinanthus freynii. The percentage of produced seeds which formed the standing seed yield was affected mainly by the collecting date.