Response of sowed, flowering herbaceous communities suitable for anthropic Mediterranean areas under different mowing regimes

Growing traditional ornamental plants in urban soil often fails, due to the low quality of the soil modified by anthropic activities. The aim of this research was to study the behavior of herbaceous plants suitable for sowing in mixes in order to revegetate soils in different urban environments. Three different mixes of herbaceous plants were studied: N (native) was composed of autochthonous species, US (urban short) and UT (urban tall) were composed of both autochthonous and allochthonous species. Plant height was lower than 60 cm in N and US, and above 60 cm in UT. Each mix was sown in three randomized plots and each plot was mown at three different times: 110, 140 and 170 days after sowing (early, mid and late season respectively). Number of plants per square meter, plant height and biomass were recorded at each mowing time. In order to assess how well the plants would establish themselves we calculated the Shannon diversity index, the evenness of species and Simpson's index of dominance. The N mix composed of autochthonous species resulted to be well-balanced with an equal number of annual and perennial species grown. The presence of annuals and perennials made the community richer and the individual plants more evenly distributed. The best mowing time to improve diversity in all the mixes was late-season. Our study suggests that native species from southern Europe are suitable for creating diverse herbaceous communities for ornamental purposes, thus enhancing the role of Mediterranean urban areas in the conservation of biodiversity.