Plant trait information is essential for understanding plant evolution, vegetation dynamics, and vegetation responses to disturbance and management. Furthermore, in Mediterranean ecosystems, changes in fire regime may be more relevant than direct changes in climatic conditions, making the knowledge of fire-related traits especially important. Thus the purpose of this data set was to compile the most updated and comprehensive information on fire-related traits for vascular plant species of the Mediterranean Basin, that is, traits related to plant persistence and regeneration after fire. Data were collected from an extensive literature review and from field and experimental observations. The data source is documented for each value. Since life history traits may vary spatially or with environmental conditions, we did not aggregate them by species; i.e., traits and species are repeated in different records if they were observed by different researchers and/or in different locations. Life history traits included in the data set are: life form, resprouting ability (after fire, after clipping, or after other disturbances that remove all the aboveground biomass), resprouting bud source, heat-stimulated germination, other germination cues, seed bank location and longevity, post-fire seedling emergence and survival, maturity age of resprouts and saplings, and seed mass. Several traits are unknown for many species; consequently, the data set reflects the state of the knowledge on the topic. However, since the ability to resprout is a trait of paramount relevance in fire-prone environments, it was considered a core trait in the data set, and thus species whose resprouting capacity was unknown were not included. Life form is also provided for all taxa. The structure of the database allows different levels of information (and accuracy) for each entry, and thus some traits may include different types of data (quantitative, semi-quantitative, or categorical) from different sources.The data set is structured in 8263 records and 11 columns, obtained from 301 published and unpublished sources of information. It includes 952 taxa determined at specific or infraspecific level, which comprise 859 species, 384 genera, and 79 families. Although this is the most comprehensive data set of fire-relevant plant traits for Mediterranean species, there is still a considerable need for observations and experiments, especially in little-studied Mediterranean areas, such as northern Africa.

No abstract

In assessing fire risk, it is important to determine whether all areas in a landscape burn at similar rates. This goal is complicated by the limitations of burned-area data and the temporally dynamic nature of landscapes. We assessed the differential degree of forest-fire burning for six landscape variables (land-use–land-cover type, distances to roads and towns, topography (slope, aspect, elevation)), each comprising several categories. The study area (95 × 55 km) was located in central Spain, and the study period covered 16 years. Landsat multispectral scanner images were used to annually map fire perimeters and to classify the landscape. We calculated an annual resource selection index for each category within a variable. The sizes and shapes of all fires occurring within a year were randomly distributed into the landscape 1000 times, and the corresponding resource selection index was calculated. This provided a null random-burning model against which we tested the actual resource selection index of the fires in each year. Pine woodlands showed consistent and significant positive fire selectivity, whereas deciduous woodlands showed consistent and significant negative selectivity. No differences in the resource selection indices of land-use–land-cover types were found between large (>100 ha) and small fires (<100 ha). Fires positively selected (resource selection index >1) areas at small or intermediate distances to towns and intermediate distances to roads. Selectivity for topographic variables was less marked. Our study demonstrates that landscape variables defining composition (land-use–land-cover type) or proximity to human influence are important factors for fire risk.

In fire-prone environments, the "event-dependent hypothesis" states that plant population changes are driven by the unique set of conditions of a fire (e.g., fire season, climate). Climate variability, in particular changes in rainfall patterns, can be most important for seeder species, since they must regenerate after fire from seeds, and for Mediterranean shrublands, given the high yearly variability of rainfall in these ecosystems. Yet, the role of rainfall variability and its interaction with fire characteristics (e.g., fire season) on plant populations has received little attention. Here we investigated the changes in seedling emergence and recruitment of three seeder species (<i>Cistus ladanifer</i>, <i>Erica umbellata</i> and <i>Rosmarinus officinalis</i>) after fires lit during three different years and at two times during the fire season (early and late in the fire season) to account for potential changes in the soil seed-bank during the year. Three plots were burned at each season, for a total of 18 plots burned during the three years. After fire, emerged seedlings were tallied, tagged and monitored during three years (two the last burning year). Rainfall during the study period was rather variable, and in some years was well below average. Seedling emergence after fire varied by a factor of 3 to 10, depending on the species and on the burning year. The bulk of seedling emergence occurred in the first year after fire, and seedling recruitment at the end of the study period was tightly correlated with this early emergence. Seedling emergence in <i>E umbellata</i> and <i>R officinalis</i>, but not in <i>C ladanifer</i>, were correlated with precipitation in the fall and winter immediately after the fire, being <i>E umbellata</i> most sensitive to low rainfall. Fire season was generally not an important factor in controlling emergence and recruitment. We discuss how projected changes in rainfall patterns with global warming can alter the balance of species in this shrubland, and can drive some species to near local extinction

The relationships between rarity (i.e., range-size, local abundance) and niche-breadth can be important to assess the risks the species face under global change, namely those resulting from fire regime change. In fire areas, germination is critical for establishing after fire for many species. We examined the relationships between rarity and germination niche-breadth for 53 plant species of two life-forms (chamaephytes and hemicryptophytes) growing in Eastern Spain. Rarity was measured as geographic range-size and as local abundance. Local abundance was evaluated at two sites differing in their post-fire successional status (a recently burned area and a long-unburned one). Germination niche-breadth was measured as the mean germination evenness index from four germination experiments that subjected the seeds to various germinating conditions characteristics of fire environments. Correlations between rarity (range-size, local abundance) and niche-breadth were calculated in cross-species mode or by way of phylogenetically independent contrasts, and either for the 53 species (all-species set) or for each of two life-form groups (chamaephytes, hemicryptophytes). In general, no significant correlations were found between the rarity measures and germination nichebreadth for the all-species set. However, significant correlations emerged when the analyses were done separating species by life-forms. Germination nichebreadth was positively correlated with range-size for chamaephytes, and negatively for hemicryptophytes. In addition, germination niche-breadth was uncorrelated, or negatively so, with local abundance for chamaephytes and hemicryptophytes, respectively. While no correlation between range-size and local abundance was found for chamaephytes, a negative one was obtained for hemicryptophytes. We conclude that rarity/germination-niche relationships varied by life-form. This pattern of relationships was obscured when all species were joined in a single group. Based on the contrasting patterns of correlations obtained for each life-form we argue that the changes in the germinating environment caused by alterations in fire regime are likely to differentially affect these two groups of species.

In fire-prone environments, the "event-dependent hypothesis" states that plant population changes are driven by the unique set of conditions of a fire (e.g. fire season, climate). Climate variability, in particular changes in rainfall patterns, can be most important for seeder species, since they regenerate after fire from seeds, and for Mediterranean shrublands, given the high yearly variability of rainfall in these ecosystems. Yet, the role of rainfall variability and its interaction with fire characteristics (e.g. fire season) on plant populations has received little attention. Here we investigated the changes in seedling emergence and recruitment of three seeder species (<I>Cistus ladanifer</I>, <I>Erica umbellata</I> and <I>Rosmarinus officinalis</I>) after fires lit during three different years and at two times (early and late) during the fire season. Three plots were burned at each season, for a total of 18 plots burned during the three years. After fire, emerged seedlings were tallied, tagged and monitored during three years (two in the last burning year). Rainfall during the study period was rather variable and, in some years, it was well below average. Postfire seedling emergence varied by a factor of 3 to 12, depending on the species and on the burning year. The bulk of seedling emergence occurred during the first year after fire; seedling recruitment at the end of the study period was tightly correlated with this early emergence. Emergence in <I>Erica</I> and <I>Rosmarinus</I>, but not in <I>Cistus</I>, was correlated with precipitation in the fall and winter immediately after fire, with <I>Erica</I> being the most sensitive to reduced rainfall. Fire season was generally neither an important factor in controlling emergence nor, in particular, recruitment. We discuss how projected changes in rainfall patterns with global warming could alter the balance of species in this shrubland, and could drive some species to near local extinction

Post-fire conditions are characterized by enhanced light and the availability of nitrogenous compounds in the soil. It is not known, however, to what extent light or nitrogenous compounds control the germination response of species growing in burned areas and, in particular, whether functional groups of plants differ in their response. The germination response to light and nitrate was tested for 53 species representative of the flora of a Mediterranean recently burned area in Central-Eastern Spain. Differences in germination among species, with and without taking into account their phylogeny, were studied by classifying them according to their life-form (chamaephytes, hemicryptophytes), regeneration strategy (non-sprouters, sprouters) and geographical distribution range (Iberian Peninsula endemics, Mediterranean, widely distributed species). The overall germination mean was not affected by any of the two treatments. There were statistically significant interactions between species and the two treatments. That is, not all species were equally affected, and about 30% of the species were significantly affected by light (half of them positively and the other half negatively) and 25% by nitrate (most of them positively). Species response was related to functional groups. Light response (stimulation vs. non-stimulation) was associated to life-form, regeneration strategy and distribution range. Hemicryptophytes, sprouters and widely distributed species were positively affected by light. No evidence of such an association for nitrate was found. No statistically significant effects of light and nitrate on the mean germination of the various groups (life-form, regeneration strategy, distribution range) were found. Moreover, significant interactions emerged between light and nitrate for all three groups. In summary, the studied set of plants appears to be nondependent on factors that may change with fire, such as increased light and soil nitrate, for germination. Nonetheless, some species and groups will be affected by such changes. That means that fire will modify the relative balance of germination among species and functional groups. Due to the particular sensitivity of Iberian Peninsula endemics to light, a factor that significantly changes with fire, these species may be at risk under the current fire regime.

Soil seed banks play a major role in the post-fire regeneration of Mediterranean shrublands. They vary throughout the year in species composition, abundance, and readiness to germinate. After fire, germination occurs mainly during the following fall to spring. Time of germination can determine recruitment success. It is unclear what factors control postfire germination and its timing. We tested the effects of season and fire on the readily germinable soil seed bank of a seeder-dominated shrubland. Plots were burned early and late in the summer season (ES, LS). Soil samples were collected before and after fire, and germinated in a chamber simulating successively autumn, winter, and spring conditions. Samples were kept moistened at all times. Fire intensity was similar between ES and LS. Several species of Cistus and herbs, mostly annuals, were dominant. Most germination occurred during the simulated-autumn period, with little subsequent germination during the following two periods. Germination speed (T 50 ) during simulated-autumn was similar for shrubs and herbs, and independent of season or fire. Germination was lower for two shrubs (Rosmarinus officinalis, Cistus salvifolius) and higher for herbaceous dicots in LS than in ES soils. Fire reduced monocots and enhanced Cistus. Germination period significantly interacted with fire and season in some groups or species, altering the simulated-autumn germination peak. We demonstrate that the seed bank can germinate swiftly under simulated-autumn conditions. Hence, water availability is the main controlling factor of germination. Fire season differentially affected some species or groups, and could affect the post-fire regeneration.