Çağatay Tavşanoğlu

Fire‐related traits for plant species of the Mediterranean Basin

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 inclu...

Local versus regional intraspecific variability in regeneration traits

Intraspecific trait variability has a fundamental contribution to the overall trait variability. However, little is known concerning the relative role of local (e.g. disturbances and species interaction) and regional (biogeographical) processes in generating this intraspecific trait variability. While biogeographical processes enhance plant trait variability between distant populations, in fire-prone ecosystems, recurrent fires may have a preponderant role in generating variability at a local scale. We hypothesize that plants respond to the local spatio-temporal heterogeneity generated by fire by having a relatively large local variability in regeneration traits in such a way that overrides the variability at a broader biogeographical scale. We test this hypothesis by assessing the intraspecific variability in fire-related regeneration traits of two species (Cistus salviifolius and Lavandula stoechas) growing in fire-prone ecosystems of the Mediterranean Basin. For each species, we selected six populations in two distant regions, three in the east (Anatolian Peninsula) and three in the west (Iberian Peninsula). For each species and population, we analysed the following regeneration traits: seed size, seed dormancy and stimulated germination by fire-related cues (heat and smoke). To evaluate the distribution of the variability in these traits, we decomposed the variability of trait values at each level, between regions (regional) and between population within region (local), using linear mixed-effect models. Despite the biogeographical and climatic differences between regions, for the two species, intraspecific variability in regeneration traits was higher at a local (within regions) than at a regional scale (between regions). Our results suggest that, in Mediterranean ecosystems, fire is an important source of intraspecific variability in regeneration traits. This supports the prominent role of fire as an ecological and evolutionary process, producing trait variability and shaping biodiversity in fire-prone ecosystems.

Seed Size Explains within-Population Variability in Post-Fire Germination of Cistus salviifolius

In fire-prone environments, studying the variability of regeneration traits is important to show the potential of plant species to survive under consecutive post-fire and fire-free conditions. We studied the relationship between seed size and germination patterns in Cistus salviifolius (Cistaceae), which is a fire-follower species distributed throughout the Mediterranean Basin. Since fire plays an important role in the life cycle of the studied species, we made a germination experiment that included a heat-shock treatment (to simulate fire) and a control without a heat-shock (to simulate fire-free conditions) using seeds collected from individual plants to assess within-population germination responses to fire. Seed germination of most of the individuals was stimulated by heat-shock, but the germination characteristics showed substantial variation among individuals within the population. Mean seed mass (i.e. seed size) was positively correlated with germination percentage in the heat treatment, but no correlation was found between seed mass and germination percentage in the control. On the other hand, mean seed mass was negatively correlated with seed mortality both in the heatshock treatment and in the control. The results show that even if the response of the majority of the individuals in the population follows the population-level germination response of the species, a significant variability in germination actually exists within this population (among individuals). Individuals with larger seeds may be favored in post-fire conditions, while seed size is unimportant in fire-free conditions. Together with the positive selective pressure of seed predation over small-seeded individuals, fire shapes the within-population variability of the regeneration traits such as seed size and post-fire germination in C. salviifolius. This variability might have evolved as a bet-hedging strategy against unpredictable conditions in the Mediterranean environment, especially the occurrence of fire and fire-free periods.

Long-term post-fire dynamics of co-occurring woody species in Pinus brutia forests: the role of regeneration mode

Regeneration mode is one of the key attributes determining population structure and dynamics of plant species. We investigated long-term patterns after fire in the cover of plant species in a 100-year chronosequence of burned Pinus brutia forests in a humid Mediterranean climate region in Turkey. Significant trends were present in the change of cover in major species through post-fire chronosequence, and species with similar trends were clustered in relation to their regeneration modes. Obligate resprouters increased their cover from the early post-fire years to the later stages, while cover of obligate seeders with a soil seed bank increased in the early years, but then decreased through time. Facultative resprouters were at an intermediate position, with an increase in cover until mid-successional stages and then a decrease through time. The cover of the only obligate seeder with a canopy seed bank (P. brutia) followed a linear increasing trend during the succession. When species with the same regeneration mode were grouped, the same trends were observed with more explained variances. A few life-history traits were enough to explain the observed trends. Our study shows that regeneration mode is an explanatory functional grouping system for describing long-term post-fire dynamics of Mediterranean Basin woody species. We suggest that regeneration mode must be a major component of any vegetation or forest stand dynamics model in the Mediterranean Basin. This result has important implications for the management of Mediterranean Basin ecosystems, and can potentially be extrapolated to other Mediterranean-type fire-prone ecosystems.

Effects of Aqueous Smoke and Nitrate Treatments on Germination of 12 Eastern Mediterranean Basin Plants

Determining the relative role of various cues on seed germination in Mediterranean plants is important to understanding their response to variable conditions. We studied germination responses of 12 eastern Mediterranean Basin species (Alyssum caricum, A. minus, Carthamus dentatus, Daucus broteri, D. carota, Hypericum aviculariifolium, Muscari comosum, Onopordum caricum, Rumex crispus, Sarcopoterium spinosum, Silene vulgaris, Smyrnium rotundifolium) to different smoke and nitrate concentrations in laboratory. Smoke treatments resulted in significant increase in germination of D. carota, O. caricum, and S. spinosum, but had a negative effect on germination of Hypericum aviculariifolium. Of the 12 studied species, five showed significant improvement in germination after at least one of the nitrate treatments compared with the control. In total, smoke and nitrate treatments significantly increased the germination percentage in six of the 12 studied species. All the species that have smoke- and/or nitrate-stimulated germination were propagule-persisters (P+), able to recruit after fire. The results reveal that both smoke and nitrate improve germination of Mediterranean species. Our results also suggest the presence of species-specific germination response to smoke and nitrate in Mediterranean plants.

Multiple fire-related cues stimulate germination in Chaenorhinum rubrifolium (Plantaginaceae), a rare annual in the Mediterranean Basin

In Mediterranean fire-prone ecosystems, annual species specific to post-fire habitats should have a soil seed bank and should be able to germinate after a fire. Therefore, various fire-related cues can be expected to stimulate germination in post-fire annuals. Germination patterns of the rare annual Chaenorhinum rubrifolium (Plantaginaceae) were examined in response to mechanical scarification, heat shock, aqueous smoke, nitrogenous compounds, gibberellic acid, karrikinolide (KAR 1 ), and mandelonitrile (a cyanohydrin analogue, MAN) under dark and photoperiod conditions in the laboratory. Combinations of these treatments were also included in the experiment. Strong physiological dormancy in the seeds of C. rubrifolium was partially broken by several fire-related germination cues, including smoke and nitrate, under light conditions. KAR 1 and MAN also stimulated germination, and the highest improvement in germination was achieved in the KAR 1 treatment in the presence of light. Heat shock + smoke and KAR 1 + MAN combinations had positive synergetic and additive effects on germination under light conditions, respectively. The light played a crucial role in the promotion of germination. The results suggest that multiple fire-related cues operate to stimulate germination in C. rubrifolium , an annual species from the Mediterranean Basin. However, the species may have a broader germination niche than a fire-restricted one.

A functional trait database for Mediterranean Basin plants

Functional trait databases are emerging as crucial tools for a wide range of ecological studies across the world. Here, we provide a database of functional traits for vascular plant species of the Mediterranean Basin. The database includes 25,764 individual records of 44 traits from 2,457 plant taxa distributed in 119 taxonomic families. This database (BROT 2.0) is an updated and enlarged version of a previous database (BROT 1.0; 8,263 records, 14 traits, 952 taxa). Trait data were obtained from a comprehensive literature review, plus some field and experimental observations. All records are fully referenced and, in many cases, include geographic coordinates. The database is structured to include different levels of accuracy of trait information for each entry. BROT 2.0 should facilitate testing hypotheses on plant functional ecology within the Mediterranean Basin, and comparing this region with other ecosystems worldwide. The BROT 2.0 database and its trait definitions can be used as a template for creating similar trait databases in other regions of the world.

Taxonomic notes on the genus Chaenorhinum (Plantaginaceae) in Turkey

Abstract Chaenorhinum gerense is an eastern Mediterranean species with rare distribution and a large variety in plant and seed morphology. In this study, the accuracy of the taxonomic status of this species, which was initially reported by P.H. Davis as C. rubrifolium from south eastern Turkey, is discussed and the typical representatives of C. rubrifolium were collected for the first time for Turkey from Muğla province, southwestern Anatolia. C. gerense is closely related to the C. rubrifolium, from which it differs by having a small and cream corolla with red blotch, capsule as long as or smaller 1/2-calyx teeth and triangular or rectangular blunt crest on seed. Detailed descriptions and identification keys for these two taxa are provided.

Modelling the drivers of natural fire activity: the bias created by cropland fires

Wildland and cropland fires, which differ considerably in fire regime characteristics, have often been evaluated jointly to estimate regional or global fire regimes using satellite-based fire activity data. We hypothesised that excluding cropland fires will change the output of the models regarding the drivers of natural fire activity. We modelled MODIS fire activity data of western and southern Turkey for the years 2000–2015 using binomial generalised linear models in which many climatic, anthropogenic and geographic factors were included as predictor variables. For modelling, we used different datasets created by the exclusion of various cropland and vegetation land cover classes. More fire activity was observed as the number of cropland-dominated cells increased in a dataset. The explained deviance (%) of the binomial GLM differed substantially in the separate datasets for most of the variables. Moreover, excluding croplands gradually from the overall dataset resulted in a substantial decrease in the explained deviance (%) in the models for all variables. The results suggest that cropland fires have a significant effect on the output of fire regime models. Therefore, a clear distinction should be drawn between wildland and cropland fires in such models for a better understanding of natural fire activity.

Inter-population variability in seed dormancy, seed mass and germination in Helianthemum salicifolium (Cistaceae), a hard-seeded annual herb

Many plant traits show variability within species in response to ecological gradients. In this study, we examined the variability in seed traits among ten populations of Helianthemum salicifolium (L.) Miller in Anatolia, Turkey. Since the Anatolian Peninsula has a geographic structure exhibiting longitudinal, elevational and climatic gradients, we hypothesized that seed dormancy, seed mass and germination show inter-population variability. We also postulated that seed traits are correlated to climatic and geographic characteristics of the populations. Since H. salicifolium is a species with a hard seed coat, we conducted germination experiments using heat shock and mechanical scarification. The germination percentage was improved significantly by mechanical scarification but remained unaltered by heat shock treatments in all sampled populations. As expected, seed traits exhibited substantial variation among the populations. We found no association between germination traits (dormancy level and germination rate in different treatments) and environmental variables. By contrast, seed mass showed an elevational/longitudinal/climatic pattern: Populations in cooler and higher-elevation areas had larger seed mass. However, when the influence of climate was controlled, the geographic location became an important factor affecting seed mass. We conclude that seed mass variation among populations of H. salicifolium in Anatolia is shaped by the climate at the regional scale, but at the same time, geographically closer populations exhibit more similarity in seed mass.