Table 1.
List of species, number of populations studied per species (#Pop), location (Country) and date (month/year) of the seed collection, and seed age at the time of the experiment (in months).
Figure 1.
Hourly register of daily temperature (°C) observed during summer on the bare soil surface of a fire-break (with no slash).
Data from a typically Mediterranean fire-prone area (August 1998, Valencia, eastern Spain [16]). Boxplots represent daily variability in temperature for each hour (n = 28 days). Dashed vertical lines represent the data within 1.5 interquartile range, and open circles are values outside this range (outliers). The continuous line represents the treatment applied to simulate summer temperatures.
Figure 2.
Germination (%) in the fire scenario and germination in the summer scenario.
Relationship between the germination (%) after the treatment of 120°C for 5 minutes (Fire scenario, y-axis) and germination after the treatment simulating temperature fluctuations in the soil in open areas during August (Fig. 1; Summer scenario, x-axis). Intraspecific variability (i.e., among populations) is indicated by small symbols (mean population value) emerging from the large symbol (mean species value; Fumana thymifolia, n = 2 populations; Cistus salviifolius, n = 6 populations; Cistus albidus, n = 4 populations; Cistus parviflorus, n = 1 population; Cistus creticus, n = 3 populations; Ulex parviflorus, n = 5 populations). The 1∶1 line is also shown (dotted line).
Table 2.
Germination percentage (mean ± SE) of untreated seeds (Control), seeds treated with summer temperature fluctuations during 30 days (Summer 30) or 5 days (Summer 5) and heat-treated seeds (Fire treatments; 80°C, 100°C, 120°C or 150°C during 5 minutes), for each species and population (location of the different populations is given in Table S1).
Table 3.
Summary of the differences in germination between untreated seeds (Control), seeds subject to a summer treatment (Summer) and seeds subject to the fire treatments, for the six species studied.
Figure 3.
Conceptual model describing recruitment dynamics in mediterranean ecosystems for species with physical dormancy.
The x-axis represents an increase in the heat doses reaching the soil (during summer or fires). The y-axis represents the proportion of recruitment associated with dormancy release, for species with different levels of fire-dependent recruitment. For some species, fire is not the main factor shaping seed dormancy and thus they have fire-independent dormancy release and recruitment (dashed line). However, species living in fire prone mediterranean ecosystems have mostly fire-dependent dormancy release, with recruitment strictly related to fire (obligate fire-dependent dormancy release, continuous line) or with a small proportion of recruitment independent of fire (facultative fire-dependent dormancy release, dotted line).