Responses of Mediterranean Plant Species to different fire frequencies in Garraf Natural Park (Catalonia,Spain): field observations and modelling predictions.

Dynamics of the coexisting Mediterranean species Pinus halepensis, Quercus coccifera, Erica multiflora, Rosmarinus officinalis, Cistus albidus, C. salviifolius and Ampelodesmos mauritanica, with contrasted life history traits have been studied under different fire scenarios, following two approaches: a) field survey in areas with three different fire histories (unburned for the last 31 years, once burned in 1982, and twice burned in 1982 and 1994), and b) simulations with different fire recurrence using the FATE vegetation model. We compared observed abundance in the field survey to simulation outputs obtained from fire scenarios that mimicked field fire histories. Substantial mismatching did not occur between field survey and simulations. Higher fire recurrences were associated with an increase in the resprouting Ampelodesmos grass, together with a decrease in Pinus abundance. Resprouting shrubs did not show contrasting changes, but trends of increase in Quercus and decrease in Erica were observed. The seeders Rosmarinus and Cistus achieved maximum abundance at intermediate fire recurrence. We also performed ten 200 year simulations of increasing fire recurrence with average times between fires of 100, 40, 20, 10, and 5 years. A scenario without fire was also simulated. High fire recurrence produces an increase in Ampelodesmos, a grass which is becoming dominant in the area, and a small increase in Erica, but Quercus abundance decreases and Pinus disappears. Rosmarinus and Cistus abundance peaks at intermediate fire frequencies. When comparing these simulations to those in which Ampelodesmos was excluded, we found that the absence of the grass only increased Cistus occurrence in the community, this effect being more important at frequent fire recurrence. The study suggests that simple models based on life history traits may be useful in interpreting plant community dynamics in Mediterranean ecosystems that are greatly influenced by differences in the fire regime.     

Linking post-fire regenerative strategy and leaf nutrient content in Mediterranean woody plants

We explored differences in leaf nutrient contents between species from Mediterranean shrublands with the ability to resprout after disturbances such as fire (resprouters) and others without this capacity (non-resprouters). Since it is to be expected that resprouting capacity is related to a more conservative use of nutrients, we hypothesize that resprouter and non-resprouter species will differ in their leaf nutrient concentrations.We measured the following leaf traits: leaf carbon content (LCC), leaf nitrogen content, leaf phosphorous content (LPC), leaf potassium content, leaf calcium content (LCaC), leaf magnesium content and leaf sodium content, in 30 woody species coexisting in a coastal shrubland. We also considered the influence of species’ taxonomic affiliation in our analysis.Non-resprouters had higher LPC and LCaC than resprouter species, and lower LCC, which could be related to their cell and life-history properties. This study also suggests that non-resprouter species have more P in their leaves and are less limited by P than resprouter species.Overall, the differences in leaf nutrient contents suggest that shifts in the proportion of resprouter and non-resprouter species resulting from changes in the fire regime may have effects on the functional properties of the ecosystem.     

Time of germination and establishment success after fire of three obligate seeders in a Mediterranean shrubland of central Spain

Aim Determining how differences in time of germination can affect plant establishment in plant communities that, after a disturbance, must reestablish from seeds under climatic conditions subject to extremes, such as the Mediterranean. Although early germination may be beneficial for survival in summer, when drought is severe, this may expose the seedlings to winter extremes, thus to higher mortality. Understanding how sensitive is the establishment of different species to temporal patterns of germination will help to understand the factors that control species distribution and community stability in disturbance‐prone environments, as well as its sensitivity to changes in weather patterns as climate changes. Methods An experimental fire was made in early fall in an old Cistus–Erica shrubland in Toledo (central Spain). After fire, germination, survival and growth of the three dominant seeder species (Cistus ladanifer, Erica umbellata and Rosmarinus officinalis) were monitored during the first 3 years after fire. Seedlings were tagged to identify their time of emergence, and divided into cohorts according to their month of germination. Differences in survival of the various cohorts were evaluated by means of a Wilcoxon (Gehan) statistic. Height of surviving, tagged plants was compared among cohorts by means of a Kolmogorov–Smirnov test. Results The year following fire was one of the driest on record, while the next one was one of the wettest. Germination was more abundant during the first than during the second year. Establishment was mainly from first‐year germination, as the majority of second‐year germinated seedlings died. Temporal patterns of germination within a year and between years varied between species. Seedling mortality was highest immediately following germination, not in summer. Mortality was related to time of germination: during a given period of time, the mortality of younger seedlings was higher than that of older ones. However, survival was not highest for the first cohorts. In general, the earlier the seedlings germinated the more vigourous they became, more clearly so for Cistus than for Rosmarinus, but differences tended to disappear with time. Overall, time of germination varied between species and affected differently seedling survival and vigour of the various species. Rosmarinus and Cistus had sufficient survivors to reestablish the initial population. Erica, despite abundant germination, suffered a strong population reduction. Main conclusions Mediterranean shrub species differ in their temporal patterns of germination and survival after fire. The effect of time of germination is complex: germinating early is advantageous since old seedlings fared better than younger ones when confronted with the same rigours. However, germinating early might expose the seedlings to greater hazards and the first cohort might not survive best. The temporal window for establishment is narrow and mainly restricted to the first year after fire. Second year seedlings, irrespective of most favourable conditions, survived very little. Missing the window of establishment might virtually lead to a population collapse, despite having very high germination, as found for Erica.     

Successional trends in standing dead biomass in Mediterranean basin species

Question: Landscape models of fire occurrence in ecosystems assume that the time since the last fire determines vegetation flammability by enabling the accumulation of dead biomass. In this study we ask if Mediterranean basin shrublands respond to these models or, on the contrary, if initial successional stages in these ecosystems could be more flammable than later stages. Location: Mediterranean shrubland in the Valencia region, eastern Spain. Methods: Using different stages of vegetation development (5, 9, 14 and 26 years since the last fire), we first study the structural comiosition of the above‐ground biomass in 375 individuals of nine woody species. Then, we measure how the standing dead biomass varies during succession, taking into account the surface cover of each species and the quantity of total dead biomass accumulated in different successional stages (3, 9, 14 and 26 years since the last fire). Results: The largest amount of standing dead biomass at the plant community level is observed in the middle stages of the succession. Early successional species, such as Cistus spp., Ulex parviflorus and Pinus halepensis, have a higher percentage of standing dead biomass at earlier stages in the succession than species typical of later successional stages, e.g. Juniperus oxycedrus, Quercus coccifera and Quercus ilex. Conclusions: The results suggest that monotonic increase in fire hazard with increasing stand age is not necessarily the rule in Mediterranean basin shrublands, since early successional species may accumulate large amounts of standing dead biomass and thus promote fire at early successional stages.     

Mesophication in temperate Europe: A dendrochronological reconstruction of tree succession and fires in a mixed deciduous stand in Białowieża Forest

1. The shift from shade‐intolerant species to shade‐tolerant mesophytic species in deciduous and mixed forests of the temperate zone is well described in studies from North America. This process has been termed mesophication and it has been linked to changes in fire regime. Fire suppression results in the cessation of establishment of heliophytic, fire‐dependent tree species such as oak (Quercus) and pine (Pinus). Due to the scarcity of old‐growth forests in Europe, data on long‐term compositional changes in mixed forests are very limited, as is the number of studies exploring whether fire played a role in shaping the dynamics.
2. The aim of this study was to reconstruct tree succession in a 43‐ha natural mixed deciduous forest stand in Bia?owie?a Forest (BF), Poland using dendrochronological methods. In addition, the presence of aboveground fire legacies (charred and fire‐scarred deadwood) enabled the fire history reconstruction.
3. Dendrochronological data revealed tree establishment (Quercus) back to the end of the 1500s and fires back to 1659. Under a regime of frequent fires until the end of the 18th century, only oak and pine regenerated, sporadically. A shift in the fire regime in the first half of the 19th century triggered oak and pine cohort regeneration, then gradually spruce (Picea) encroached. Under an increasingly dense canopy and less flammable conditions, regeneration of shade‐tolerant Carpinus, Tilia, and Acer began simultaneously with the cessation of oak and pine recruitment.
4. Synthesis. The study reports the first evidence of mesophication in temperate Europe and proves that fire was involved in shaping the long‐term dynamics of mixed deciduous forest ecosystems. Our data suggest that fire exclusion promoted a gradual recruitment of fire‐sensitive, shade‐tolerant species that inhibited the regeneration of oak and pine in BF.

     

Response to recurrent disturbance in two co-occurring resprouter heath species: the ecological consequences of withstanding herbivores

Resprouting woody plants are vulnerable to large mammal herbivores in the early stages of regeneration after disturbance (e.g., fire, slashing), because herbivory reduces the storage of below-ground starch reserves and may thus compromise regeneration success. Defence from herbivory may incur a cost to resprouter plants in terms of lengthening the time to recovery of pre-disturbance starch levels. Erica scoparia and E. australis (Ericaceae), two resprouter woody species that co-occur in Mediterranean heath-communities of the Strait of Gibraltar, differ in the way they cope with herbivory: E. scoparia is browsing-tolerant and E. australis is a browsing-avoider. Our experimental field study demonstrated that exposure to a moderate density of ungulate herbivores markedly lowered starch re-storage after resprouting in E. scoparia, but not in E. australis. Nevertheless, time to recover pre-disturbance starch levels was shorter in the tolerant E. scoparia, even under exposure to herbivores. The slower starch recovery rate of E. australis is a likely outcome of its resource-demanding browsing-avoidance mechanism. Differences in starch recovery rates after disturbance between the two Erica species partly explains their ecological segregation at the landscape scale.     

POSTFIRE RESPONSE AND GENETIC DIVERSITY IN ERICA COCCINEA: CONNECTING POPULATION DYNAMICS AND DIVERSIFICATION IN A BIODIVERSITY HOTSPOT

Understanding the processes of biological diversification is a central topic in evolutionary biology. The South African Cape fynbos, one of the major plant biodiversity hotspots out of the tropics, has prompted several hypotheses about the causes of generation and maintenance of biodiversity. Fire has been traditionally invoked as a key element to explain high levels of biodiversity in highly speciose fynbos taxa, such as the genus Erica. In this study, we have implemented a microevolutionary approach to elucidate how plant‐response to fire may contribute to explain high levels of diversification in Erica. By using microsatellite markers, we investigated the genetic background of seeder (fire‐sensitive) and resprouter (fire‐resistant) populations of the fynbos species Erica coccinea. We found higher within‐population genetic diversity and higher among‐population differentiation in seeder populations and interpreted these higher levels of genetic diversification as a consequence of the comparatively shorter generation times and faster population turnover in the seeder form of this species. Considering that genetic divergence among populations may be seen as the initial step to speciation, the parallelism between these results and the pattern of biodiversity at the genus level offers stimulating insights into understanding causes of speciation of the genus Erica in the Cape fynbos.     

A long‐term record of Quercus decline,logging and fires in a southern Swedish Fagus‐Picea forest

Abstract. We reconstructed forest development and disturbance events (fire and logging) during the last 1000 yr with tree‐ring data, pollen and charcoal analysis from a semi‐natural Fagus sylvatica‐Picea abies forest (ca. 1 km²) in the hemiboreal zone. According to pollen analysis, Quercus robur together with Pinus sylvestris was abundant in the forest until the turn of the 18th/19th centuries when these species disappeared completely (Quercus) or nearly completely (Pinus) and were replaced by Fagus and Picea. The disappearance of Quercus was corroborated by the remarkable discovery of a single Quercus stump that had been cut in the 18th century and had become overgrown and preserved by a very old Picea. In total 11 fires were dated from 1555 to 1748 from fire scars in several Pinus stumps cut 100 ‐ 200 yr ago. Since the last fire in 1748, no Quercus or Pinus have regenerated in the core of the reserve apart from single pines in neighbouring managed forest (80 yr ago). During the period of documented fires Fagus was protected from fires in a refuge made up of large boulders. Picea colonized the region at the time when the fires ceased 250 yr ago. We hypothesize that most of the fires were probably of human origin because of their patchiness and high frequency compared to the natural background levels of lightning ignitions in the region. On a 300‐yr time scale, logging and fire suppression seem to strongly overshadow the effect of climate change on forest composition and dynamics.     

Succession of secondary forests affected by pine wilt disease in western Japan followed on vegetation maps

Abstract. Succession, changes in the distribution pattern of forest vegetation, and Pinus forest survival following pine wilt disease were clarified based on phytosociological analysis and vegetation maps. Survival of Pinus forests was restricted to the early successional stages, which were located on ridges and the upper part of slopes. Subsequent to pine wilt disease, the succession progressed from early to late substages of Pinus forest, mixed deciduous and evergreen Quercus, to evergreen Quercus forest. Succession occurs in abandoned pine forests which apparently are in a bad state and are vulnerable to attacks by pine wilt disease.     

Spatial pattern of seedlings 1 year after fire in a Mediterranean pine forest

Summary The spatial distribution of seedlings of the dominant perennial plant species (Pinus halepensis, Cistus salviifolius, Rhus coriaria) and may annual species was studied after a wild fire in an eastern Mediterranean pine forest. The spatial distribution of all seedlings is affected by the location of the old burned pine trees. Seedling density of Pinus and Cistus is higher at a distance from the burned pine canopy and lower near the burned pine trunk. It is also higher beneath small burned pine trees than under big ones. Rhus seedling density is higher under big burned pine trees and also near the burned trunks. Seedlings of Pinus, Cistus and Rhus growing under the burned canopy of big pine trees tend to be taller than seedlings under small ones or outside the burned canopy. Most annual species germinate and establish themselves outside the burned canopies, and only a few annual species are found beneath them. It is suggested that variation in the heat of the fire, in the amount of ash between burned pine trees of different sizes, and in the distance from the burned canopy are responsible for the observed pattern of seedling distribution. The possible ecological significance of the spatial pattern of seedlings distribution and their differential growth rate are discussed.     

A study of variation in the pollen spectra of honeys sampled from the Baixa Limia‐Serra do Xurés Nature Reserve in north‐west Spain

The pollen content of eleven honey samples from ten different apiaries in the Baixa Limia – Serra do Xurés Nature Reserve and other honey commercialised by the cooperative as “Mel do Xurés” (north‐west Spain) was subjected to quantitative and qualitative melissopalynological analysis. The quantitative analysis found that ten samples belonged to Maurizio's Class III and one to Class IV. According to the qualitative analysis, four samples were classified as unifloral honey with Erica, four samples as multifloral honey with Erica pollen as the principal component and three samples as multifloral honey with Cytisus‐type pollen and Erica as the principal component pollen. The pollen spectra differ between the diverse honeys analysed, with a common denominator being Erica and Cytisus‐type pollen being abundant in all. For the rest of the samples, the pollen spectra were mainly the same, but with different relative percentages among secondary elements. Thus, either as a secondary or an important element, 91% of the honeys contained Quercus, 82% Castanea sativa Miller, 45% Rubus, 36% Cistus and 27% Lithodora prostrate (Loisel) Griseb,. In particular, we record for the first time the presence of Ribes and Ilex aquifolium L. pollen in Spanish honeys as an important minor or minor pollen component.     

Post‐fire succession and 20th century reduction in fire frequency on xeric southern Appalachian sites

Abstract. We document post‐fire succession on xeric sites in the southern Appalachian Mountains, USA and assess effects of 20th century reduction in fire frequency on vegetation structure and composition. Successional studies over 18 yr on permanent plots that had burned in 1976–1977 indicate that tree mortality and vegetation response varied with fuel load and fire season. In the first three years after fire, hardwood sprouts dominated tree regeneration. On sites where summer and autumn fires reduced litter depth to less than 1 cm, densities of shade‐intolerant Pinus seedlings increased steadily over this period. 4 to 8 yr after fire, large numbers of newly established seedlings and sprouts had grown to 1 – 10 cm DBH. By year 18 growth of these saplings led to canopy closure on most sites. Herbaceous cover and richness peaked in the first decade after fire, then declined. On similar sites that had not burned in more than 50 yr, regeneration of shade‐intolerant Pinus spp. and mean cover and richness of herbs were considerably lower than those observed on recently burned plots. Reconstructions of landscape conditions based on observed post‐fire succession and 20th century changes in fire regime suggest that reductions in fire frequency circa 1940 led to substantial changes in forest structure and decreases in cover and richness of herbaceous species.     

Old-field secondary succession in SE Spain: can fire divert it?

In the Mediterranean Basin, most cultivated areas were abandoned in the last century and are now in various stages of old-field succession. The aim of this work was to analyse the successional trajectories of these ecosystems, and to assess possible deviations in these pathways due to fire occurrence at high or low recurrence levels. Old-fields abandoned either about 50 or about 100 years ago were selected in SE Spain. Within the 50-year-old abandoned fields, plots were established which had been burned by 1, 2 and 3 fires in the last 25 years. Cover values of vascular species were sampled and then analysed by means of multivariate analysis. Euclidean distances between resulting communities were used as an indicator of the possible deviation from the unburned successional pathway. Our results pointed to the possibility that different successional pathways may exist depending on fire occurrence and recurrence. In the absence of fire, the vegetation is dominated by pioneer species, mainly Pinus. With the passage of time this vegetation will become dominated by later successional tree species (Quercus). However, when early-successional communities are affected by fire, the succession can be diverted. A single fire is enough to change Pinus forests into alternative stable states dominated by Rosmarinus officinalis shrub communities, where the colonisation of species in later successional stages is arrested. This deviation increases in high fire recurrence regimes where the vegetation changes to dwarf shrubs and herbs.     

Modern pollen and vegetation relationships in the mountains of southern California,USA

The relationship between modern pollen assemblages and modern vegetation along two elevational transects within the Transverse and Peninsular Ranges of southern California, USA, is demonstrated using cluster analysis of the pollen data. Cluster analysis separates the Sonora Desert vegetation, Valley grassland/agricultural land and chaparral vegetation types on the San Jacinto Mountains transect. Chaparral is not easily separated on the San Bernardino Mountains transect, probably due to the presence of Quercus dumosa (scrub oak) there. The lower montane Quercus – Pinus (oak – pine) community is distinct from other forest types, and can be subdivided palynologically based upon relative importance of Quercus, Pinus and Cupressaceae [primarily Calocedrus decurrens (incense cedar)] pollen. Subdivisions include Quercus – Pinus – Cupressaceae, Quercus – Cupressaceae – Pinus and Quercus – Pinus assemblages. Higher elevation Pinus – Abies (pine – fir) and Pinus-dominated communities are also differentiated from one another, although the subalpine vegetation type only occurs on the San Bernardino Mountains transect. Though the study area presently straddles a transition between winter-wet and summer-wet climatic regimes, differences between the pollen assemblages in the two mountain ranges are minimal. Pollen assemblages from lower elevations document the effects of human activities, primarily agriculture, on the modern pollen rain of the region, with the occurrence of introduced citrus (Citrus sp.) and shade (Eucalyptus sp.) trees and weedy disturbance indicators (e.g., Brassicaceae).     

Leaf physiological traits in relation to resprouter ability in the Mediterranean Basin

In Mediterranean ecosystems, fire is a strong selective agent among plants, and the different post-fire regeneration strategies (e.g. resprouting and non-resprouting) have implications for other plant traits. Because young plants of non-resprouters need to grow quickly and mature well before the next fire, we predict that they should possess leaf traits related to increased efficiency in growth and resource acquisition compared with resprouter species. To test this hypothesis, we measured specific leaf area, leaf nitrogen and carbon concentrations and leaf physiological traits, including gas exchange parameters and chlorophyll fluorescence, in 19 Mediterranean species cultivated in a common garden. Both cross-species and phylogenetically informed analyses suggest that non-resprouters have better physiological performance at the leaf level (i.e. higher photosynthetic capacity) than resprouters. All these results suggest that non-resprouter species are able to take greater advantage for vegetative growth and carbon fixation than resprouters during periods when water is readily available. The contrasted physiological differences between resprouters and non-resprouters reinforce the idea that these two syndromes are functionally different (i.e. they are functional types).     

What predicts the richness of seeder and resprouter species in fire‐prone Cape fynbos: Rainfall reliability or vegetation density?

In ecosystems subject to regular canopy fires, woody species have evolved two general strategies of post‐fire regeneration. Seeder species are killed by fire and populations regenerate solely by post‐fire recruitment from a seed bank. Resprouter species survive fire and regenerate by vegetative regrowth from protected organs. Interestingly, the abundance of these strategies varies along environmental gradients and across regions. Two main hypotheses have been proposed to explain this spatial variation: the gap dependence and the environmental‐variability hypotheses. The gap‐dependence model predicts that seeders are favoured in sparse vegetation (vegetation gaps allowing effective post‐fire recruitment of seedlings), while resprouters are favoured in densely vegetated sites (seedlings being outcompeted by the rapid crown regrowth of resprouters). The environmental‐variability model predicts that seeders would prevail in reliable rainfall areas, whereas resprouters would be favoured in areas under highly variable rainfall that are prone to severe dry events (leading to high post‐fire seedling mortality). We tested these two models using distribution data, captured at the scale of quarter‐degree cells, for seeder and resprouter species of two speciose shrub genera (Aspalathus and Erica) common in fire‐prone fynbos ecosystems of the mediterranean‐climate part of the Cape Floristic Region. Contrary to the predictions of the gap‐dependence model, species number of both resprouters and seeders increased with values of the Normalized Difference Vegetation Index (a widely used surrogate for vegetation density), with a more marked increase for seeders. The predictions of the environmental‐variability hypothesis, by contrast, were not refuted by this study. Seeder and resprouter species of both genera showed highest richness in environments with high rainfall reliability. However, with decreasing reliability, seeder numbers dropped more quickly than those of resprouters. We conclude that the environmental‐variability model is better able to explain the abundance of woody seeder and resprouter species in Southern Hemisphere fire‐prone shrublands (fynbos and kwongan) than the gap‐dependence model.     

Socioeconomic Factors Drive Fire-Regime Variability in the Mediterranean Basin

In recent decades, fires in Mediterranean Europe have become larger and more frequent. This trend has been driven by socioeconomic changes that have generated rural depopulation and changes in traditional land use. Within the Mediterranean Basin, the most contrasting socioeconomic conditions are found by comparing southern European with North African countries, and thus our hypothesis is that this difference generates contrasting fire regimes between the two regions. Specifically, we predict that current fire regimes in Mediterranean Africa resemble past fire regimes in the Mediterranean Europe when rural activities dominated the landscape. To test our hypothesis, we compared fire statistics from the western Rif (northern Morocco, 1988–2015) and from Valencia (eastern Spain, 1880–2014). The results suggest that the Rif has a typical Mediterranean fire regime with fires occurring in the hot, dry summer season. However, fires are very small and the annual proportion of burnt area is very low, compared to the current regime in Valencia (post-1970s). The current Rif fire size class distribution matches the fire regime in Valencia prior to the 1970s before the collapse of the rural population and when fires were fuel-limited. The shift in the recent decades in fire regime observed in different countries of the Mediterranean Europe (from small, fuel-limited fires to drought-driven fires) can be identified when moving from the southern to the northern rim of the basin. That is, most spatial and temporal variability in fire regimes of the Mediterranean Basin is driven by shifts in the amounts of fuel and continuity imposed by changes in socioeconomic drivers.     

Effects of repeated burning on Mediterranean communities of the northeastern Iberian Peninsula

Question: In relation to a single fire, do repeated wildfires in Mediterranean type ecosystems (1) reduce plant species richness or diversity; (2) modify patterns of abundance or dominance of plant species or (3) alter plant composition? Location: Pinus halepensis dominated communities of Catalonia, northeastern Iberian Peninsula, western Mediterranean Basin. Methods: Regional, paired design with 14 study sites, each consisting of a once burnt area (1994) and a twice burnt area (1975–1993 and 1994). Ten years after the last fire, we recorded all vascular plant species present in nested plots and quantified their relative abundances on transects. We compared species richness, diversity, dominance and relative abundance and species‐area correlations between paired once and twice burnt areas and assessed their floristic composition similarity. Results: No statistically significant differences were found in species richness or diversity. Slopes of species‐area correlations were higher in once burnt areas. In twice burnt areas, dominance by one or two species was higher. P. halepensis showed lower relative abundance and nanophanerophytes showed higher relative abundance. No differences were found for resprouter, seeder or resprouter‐seeder species. Floristic composition similarity between paired areas tended to be higher in less productive sites. Conclusions: Fire recurrence had contrasting effects on species richness at different spatial scales. Repeated burning reduced the relative abundance of the dominant tree species, which resulted in a higher relative abundance of shrubs. It also promoted the dominance of herbs, particularly Brachypodium retusum. However, it did not change the relative abundance of regenerative groups. Paired areas were more similar as they were more Mediterranean in terms of climatic conditions.     

Isolation and characterization of microsatellite loci in the Cape fynbos heath Erica coccinea (Ericaceae)

Enriched genomic libraries were used to isolate and characterize dinucleotide microsatellite loci in Erica coccinea, a South African Cape fynbos heath species with distinct resprouter and seeder populations. Microsatellites were required to investigate the effect of the contrasting demographic pattern driven by these two post-fire responses in the population genetic structure of seeder and resprouter forms within this species. Eight microsatellite loci were characterised and amplified a total of 106 alleles in 2 samples each of 30 individuals from 1 resprouter and 1 seeder population. Mean allele numbers were 7.88 and 11.0 for the resprouter and seeder population, respectively. Both populations showed similar average observed and expected heterozygosity levels, H _O(resprouter) = 0.683, H _O(seeder) = 0.696; H _E(resprouter) = 0.726, H _E(seeder) = 0.756, and average positive inbreeding coefficients F _IS(resprouter) = 0.058, F _IS(seeder) = 0.080. This set of microsatellite loci will be used to conduct a population genetic survey of seeder and resprouter populations throughout the range of the species. Cross-species transferability was also assayed in four other South African and four European species of the genus Erica, supporting their potential use for population genetic analyses.     

Vegetation recovery after fuel management in Mediterranean shrublands

Question: What is the effect of fuel management practices in the recovery capacity of seeder‐dominated shrublands? Location: Ulex parviflorus shrubland localities in Mediterranean regions of eastern Spain. Methods: We applied prescribed burning and brush‐chipping as fuel management techniques in three young and three mature shrublands, and evaluated the effects in the following four years. Results: Canopy opening by the treatments allowed increasing species richness through the four years of secondary succession. The treatments produced a change in community structure and dominant species, from the woody seeder Ulex parviflorus to the resprouter grass Brachypodium retusum. Vegetation response was conditioned by both shrubland developmental stage and treatment applied. Burning resulted in more severe modification of the ecosystem, increasing bare soil cover. Four years after fuel management in different aged Mediterranean gorse shrublands, vegetation response followed a similar pattern with the exception of the young, brush‐chipped shrublands. The treatments applied for controlling Ulex parviflorus were seen to be very effective, with the exception of brush‐chipping in young shrublands. Conclusions: Selective brush‐chipping in middle‐aged or mature gorse shrublands would combine a drastic reduction in fire hazard with ecosystem conservation and regeneration.