Assessing and modeling seed germination of Mediterranean wildflowers for low input landscape restoration

Native species are recommended for use in landscape restoration because they adapt well to the local pedo-climatic conditions. Despite the high biodiversity in the Mediterranean, the use of native plants is hampered by the limited knowledge of their seed germination. This is particularly true for a number of plants which are appropriate for creating species-rich herbaceous communities. In this study, seeds of 35 species were collected in different roadside and degraded sites in rural and urban areas. Two experiments were carried out to determine the influence of light and thermal conditions on seed germination. In the first experiment, seeds of 17 species were tested at different temperatures (5, 15, and 25°C). At 15°C, seed germination was tested under both dark and light conditions. In the second experiment, the germination of 30 species was tested under alternating temperatures (25/15°C) and dark/light conditions. The responses of the various species differed in relation to thermal levels and light conditions, e.g., Bartsia trixago did not germinate in the dark at constant temperatures (5, 15, and 25°C), while in the light (15°C) and at alternating temperatures (25/15°C) in light and dark conditions, germination was over 60%. In both experiments, Tragopogon porrifolius and Triticum ovatum showed the highest germination rate (>=88%). With the sole exception of Medicago orbicularis, all members of the Fabaceae showed no or low germination. The definition of the germination requirements of some Mediterranean species, highlighted in these experiments, provides useful information for the creation of low input green areas and environmental restoration using these species.