Competitive ability of three native grass species during establishment

Abstract

Weed resistance is highly desirable in seed used for restoration. Therefore, assessing the competitiveness of target species during germination and establishment stages would help to plan effective restoration projects. Our study aims to assess the impact of competition in seedling establishment, height, leaf number, and aerial biomass of three native perennial forage grasses with different seed sizes. We conducted a competition experiment under greenhouse conditions with three native species Nassella longiglumis, N. tenuis and Piptochaetium napostaense), and one exotic annual species (Avena barbata). Two competition levels were established (with and without A. barbata) and two seeding densities for the perennial species were defined (15 and 30 seeds per pot). Established seedlings, leaf number, height and aerial biomass were measured. Seedling establishment was affected by competition only for N. tenuis. For all three species, N. longiglumis, with the larger seed size, was the least affected by competition. Competition reduced seedling biomass for all three species, with N. longiglumis, with the larger seed size, being the least affected. Increasing seeding density has little effect on the aerial biomass of the weed.The co-occurrence of native perennial species and the annual species A. barbata severely reduces growth, therefore it is important to implement management practices to control annual exotic species and effectively restore grassland ecosystems.