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29 páginas, 7 tablas, 4 figuras., The plant variability in the southern Iberian Peninsula consists of around 3500 different taxa due to its high bioclimatic, geographic, and geological diversity. The deciduous forests in the southern Iberian Peninsula are located in regions with topographies and specific bioclimatic conditions that allow for the survival of taxa that are typical of cooler and wetter bioclimatic regions and therefore represent the relict evidence of colder and more humid paleoclimatic conditions. The floristic composition of 421 samples of deciduous forests in the south-central part of the Iberian Peninsula were analyzed. The ecological importance index (IVI) was calculated, where the most important tree species were Quercus pyrenaica, Acer opalus subsp. Granatensis, and Corylus avellana. These species are uncommon in the south-central part of the Iberian Peninsula, forming forests of little extension. An analysis of the vertical distribution of the species (stratum) shows that the majority of the species of stratum 3 (hemicriptophics, camephytes, geophites, and nanophanerophytes) are characteristic of deciduous forests, and their presence is positively correlated with high values of bioclimatic variables related to humidity and presence of water in the soil (nemoral environments), while they are negatively correlated with high values of bioclimatic variables related to high temperatures, evapotranspiration, and aridity. This work demonstrates that several characteristic deciduous forest taxa are more vulnerable to disappearance due to the loss of their nemoral conditions caused by gaps in the tree or shrub canopy. These gaps lead to an increase in evapotranspiration, excess insolation, and a consequent loss of water and humidity in the microclimatic conditions., This research received no external funding. Acknowledgments: Pru Brooke Turner (MA Cantab.) for the English translation of this article and the anonymous reviewers who have improved our manuscript with their comments.

Navarro-Cerrillo, R. M., Clavero, I., Lorenzo Vidana, A., Quero J. L., Duque-Lazo J. 2016. Forest Inventories and habitat models to predictregeneration of Mediterranean woody species in forest plantations. Ecosistemas 25(3): 6-21. Doi.: 10.7818/ECOS.2016.25-3.02 Can we model the potential habitat of natural regeneration of Mediterranean woody species in forest plantations using distribution models? In this paper, dasometric variables from a forest inventory of Sierra de Baza Natural Park, combined with environmental variables (climatic, topographic) and biotic variables were analyzed to assess which factors influence the regeneration of seven woody species (Pinus sylvestris, P. nigra, P. pinaster, P. halepensis, Quercus ilex, Crataegus monogyna and Acer opalus). Modeling potential habitat for regeneration was done using Maxent in the current climate, and two future climate scenarios. The combination of biotic and climatic variables was important to predict regeneration of Pinus species, A. opalus subsp. granatense and C. monogyna, while the regeneration of Q. ilex was more related to climate predictors. In future climate change scenarios, P. halepensis optimum regeneration habitat could increase significantly, whereas the remaining species tend to moderate decreases (25%) for the period 2000-2050. Our results highlight the importance of species distribution models as a useful tool for achieving greater naturalization of forest plantations by identifying areas of future climatic optimum distribution. We further demonstrate the potential of forest inventory data to monitor changes in regeneration and prioritize restoration actions to facilitate regeneration.

The effects of changes in structure and composition on the dynamics and responses of secondary forests to climate change are understudied. Secondary forests of Abies pinsapo var. maroccana are often a mosaic of patches of various development stages showing different stand structures and successional stages. We hypothesise that the structure, species composition and tree-to-tree competition of A. pinsapo stands in Talassemtane National Park (Riff in northern Morocco) modulate the potential response of these secondary forests to climate change. Nine plots representing three species mixtures were established in A. pinsapo-dominated forests, and dendrometric and dendroecological surveys were conducted. The two-parameter Weibull function was used to investigate the diameter distributions of Abies pinsapo, Pinus nigra subsp. mauritanica. Cedrus atlantica, Acer opalus, Juniperus oxycedrus and Quercus ilex for each site along the compositional gradient. We quantified changes in radial growth, response to climate and drought, and components of growth resilience. Finally, the influence of neighbourhood competition on individual tree growth was evaluated using the a competition index. Diameter distributions had an exponential, reverse-J character for A. pinsapo in pure and C. atlantica mixed stands. By contrast, A. pinsapo presented a positively-skewed diameter distribution dominated by small-sized trees in P. nigra mixed stands. There was a significant correlation between tree growth and climate on all forest types, with differing magnitudes per species. Significant precipitation-growth correlations were found for the previous autumn and winter (October, December) in A. pinsapo. Drought events reduced A. pinsapo’s resistance to subsequent droughts when growing in pure and mixed stands with C. atlantica. This decline was statistically significant by the end of the studied period (1999–2005). In contrast, mixed forests showed the highest recovery after drought. Successive drought events consistently reduced A. pinsapo‘s resilience to drought, regardless of species composition. In pure A. pinsapo and in A. pinsapo-C. atlantica mixed forests, competition reduced A. pinsapo’s growth, while in A. pinsapo-P. nigra mixed forests increased competition with P. nigra seemed to have a positive-to-neutral effect on A. pinsapo growth. Here, we showed that the response to climate and resilience of A. pinsapo forests could be severely influenced by structure, species composition, and competition, potentially influencing our expectations of long-term persistence of old-growth coniferous trees in the Riff mountains. Understanding forest resilience and response to changing climate has important implications towards managing and safeguarding the productivity and health of these old growth forests.

Variation in flowering phenology is common in natural populations, and is expected to be, together with inter-mate distance, an important driver of effective pollen dispersal. In populations composed of plants with temporally separated sexual phases (i.e. dichogamous or heterodichogamous populations), pollen-mediated gene flow is assumed to reflect phenological overlap between complementary sexual phases. In this study, we conducted paternity analyses to test this hypothesis in the temporally dimorphic tree Acer opalus. We performed spatially explicit analyses based on categorical and fractional paternity assignment, and included tree size, pair-wise genetic relatedness and morph type as additional predictors. Because differences between morphs in flowering phenology may also influence pollination distances, we modelled separate pollen dispersal kernels for the two morphs. Extended phenological overlap between male and female phases (mainly associated with inter-morph crosses) resulted in higher siring success after accounting for the effects of genetic relatedness, morph type and tree size, while reduced phenological overlap (mainly associated with intra-morph crosses) resulted in longer pollination distances achieved. Siring success also increased in larger trees. Mating patterns could not be predicted by phenology alone. However, as heterogeneity in flowering phenology was the single morph-specific predictor of siring success, it is expected to be key in maintaining the temporal dimorphism in A. opalus, by promoting not only a prevalent pattern of inter-morph mating, but also long-distance pollination resulting from intra-morph mating events. Fil: Gleiser, Gabriela Laura. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Ecotono; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Chybicki, I.J.. Kazimierz Wielki University; Polonia Fil: González Martínez, S.C.. Institut National de la Recherche Agronomique; Francia. Universite de Bordeaux; Francia Fil: Aizen, Marcelo Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Ecotono; Argentina

The major goal of landscape genetics is to understand how landscape structure genetic variation in natural populations. We investigated molecular diversity in Acer opalus subsp. obtusatum sampled from 95 sites using 14 nuclear microsatellite loci. The average number of alleles per nuclear microsatellite locus differed among sampling sites; the number was high (4.9 alleles) in populations from the Basilicata and Molise regions, where heterozygosity was also high (0.679, Molise; 0.669, Basilicata). Differentiation between sites was often low (mean FST = 0.220), indicating few genetic differences between most sites. There was a clear excess of homozygotes (mean Ho = 0.450, mean He = 0.513) and a relatively high FIS (mean = 0.451), suggesting a consistent level of inbreeding in many A. opalus subsp. obtusatum populations. There was a significant pattern of isolation by distance across the study area (Mantel test; R2 = 0.0662, P

14 paginas, 3 figuras, 5 tablas., In sexually polymorphic species, the morphs are maintained by frequency-dependent selection through disassortative mating. In heterodichogamous populations in which disassortative mating occurs between the protandrous and protogynous morphs, a decrease in female fitness in one morph is hypothesized to drive sexual specialization in the other morph, resulting in dimorphic populations. We test these ideas in a population of the heterodichogamous species, Acer opalus. We assessed both prospective gender of individuals in terms of their allocations and actual parentage using microsatellites; we found that most matings in A. opalus occur disassortatively. We demonstrate that the protogynous morph is maintained by frequency-dependent selection, but that maintenance of males versus protandrous individuals depends on their relative siring success, which changes yearly. Seeds produced later in the reproductive season were smaller than those produced earlier; this should compromise reproduction through ovules in protandrous individuals, rendering them male biased in gender. Time-dependent gender and paternity analyses indicate that the sexual morphs are specialized in their earlier sexual functions, mediated by the seasonal decrease in seed size. Our results confirm that mating patterns are context-dependent and change seasonally, suggesting that sexual specialization can be driven by seasonal effects on fitness gained through one of the two sexual functions., We thank the staff of the Parque Natural Carrascal de la Font Roja for giving us permission to perform this study in the natural park. This study was funded by aMEC/CICYT (REPROFOR AGL2005-07440-C02-02/FOR) project grant to MV, a I3P/CSIC postdoctoral grant to JGS-M and a FPU/MEC Ph.D. grant to GG.

10 paginas, 3 figuras., Background and Aims Heterodichogamy (a dimorphic breeding system comprising protandrous and protogynous individuals) is a potential starting point in the evolution of dioecy from hermaphroditism. In the genus Acer, previous work suggests that dioecy evolved from heterodichogamy through an initial spread of unisexual males. Here, the question is asked as to whether the different morphs in Acer opalus, a species in which males co-exist with heterodichogamous hermaphrodites, differ in various components of male in fitness. Methods Several components of male fertility were analysed. Pollination rates in the male phase were recorded across one flowering period. Pollen viability was compared among morphs through hand pollinations both with pollen from a single sexual morph and also simulating a situation of pollen competition; in the latter experiment, paternity was assessed with microsatellite markers. It was also determined whether effects of genetic relatedness between pollen donors and recipients could influence the siring success. Finally, paternal effects occurring beyond the fertilization process were tested for by measuring the height reached by seedlings with different sires over three consecutive growing seasons. Key Results The males and protandrous morphs had higher pollination rates than the protogynous morph, and the seedlings they sired grew taller. No differences in male fertility were found between males and protandrous individuals. Departures from random mating due to effects of genetic relatedness among sires and pollen recipients were also ruled out. Conclusions Males and protandrous individuals are probably better sires than protogynous individuals, as shown by the higher pollination rates and the differential growth of the seedlings sired by these morphs. In contrast, the fertility of males was not higher than the male fertility of the protandrous morph. While the appearance of males in sexually specialized heterodichogamous populations is possible, even in the absence of a fitness advantage, it is not clear that males can be maintained at an evolutionary equilibrium with two classes of heterodichogamous hermaphrodites., We thank Jaume Tormo, Yolanda Orduna and Tono Bellido for field assistance, and the staff of the Parque Natural Carrascal de la Font Roja for giving us permission to conduct this study in the natural park. This study was funded by a MEC/CICYT (REPROFOR AGL2005–07440-C02-02/FOR) project grant to M. Verdú, a I3P/ CSIC postdoctoral grant to J.G. Segarra-Moragues and a FPU/MEC PhD grant to G. Gleiser.

Question: Positive interactions are predicted to be common in communities developing under high physical stress or high herbivory pressure due to neighbour amelioration of limiting physical and consumer stresses, respectively. However, when both stress sources meet in the same community, the relative importance of the two facilitation mechanisms is poorly understood. We ask: What is the relative importance of abiotic vs. biotic mechanisms of facilitation of tree saplings by shrubs in Mediterranean mountain forests? Location: Sierra Nevada, SE Spain (1800–1850 m a.s.l.) Methods: Saplings of four tree taxa (Acer opalus ssp. granatense, Quercus ilex, Pinus nigra ssp. salzmanii and P. sylvestris var. nevadensis) were planted following a 2 × 2 factorial design: two levels of herbivory (control and ungulate exclusion) and two microhabitats (under shrubs and in open areas). Sapling survival and growth were monitored for five years. Results: Shrubs had positive effects on sapling survival both in control...

Seed dispersal can severely limit the quantity of plant recruits and their spatial distribution. However, our understanding of the role of dispersal in regeneration dynamics is limited by the lack of knowledge of seed deposition patterns in space and time. In this paper, we analyse the spatiotemporal variability of seed dispersal patterns in the Mediterranean maple, Acer opalus subsp. granatense, by monitoring seed rain along two years at a broad spatial scale (2 mountain ranges, 2 populations per range, 4 microhabitats per population). We quantified seed limitation and its components (source and dispersal limitation), and explored dispersal limitation in space by analysing dispersal distances, seed aggregation, and microhabitat seed distribution. Acer opalus subsp. granatense was strongly seed-limited throughout the gradients explored, being always dispersal limitation much higher than source limitation. The distribution of seeds with distance from adult individuals was leptokurtic and right-skewed in all populations, being both kurtosis and skewness higher the year of the highest seed production. Dispersal distances were shorter than expected by random in the four populations, which suggests distance-limited dispersal. Dispersal patterns were highly aggregated and showed a preferential direction around adults. At the microhabitat scale, most seeds accumulated under adult maples. However, there were no more seeds under trees and shrubs other than maple than in open interspaces, implying that established vegetation does not disrupt patterns of seed deposition by physically trapping seeds. When compared with patterns of seedling establishment, limited dispersal ability and inter-annual spatial concordance in seed rain patterns suggest that several potentially safe sites for recruitment have a very low probability of receiving seeds in most maple populations. These findings are especially relevant for rare species such as Acer opalus subsp. granatense, and illustrate how dispersal studies are not only crucial for our understanding of plant population dynamics but also to provide conservation directions.

[Departement_IRSTEA]Territoires [TR1_IRSTEA]SEDYVIN; International audience; Long-term records of rockfalls have proven to be scarce and typically incomplete, especially in increasingly urbanized areas where inventories are largely absent and the risk associated with rockfall events rises proportionally with urbanization. On forested slopes, tree-ring analyses may help to fill this gap, as they have been demonstrated to provide annually-resolved data on past rockfall activity over long periods. Yet, the reconstruction of rockfall chronologies has been hampered in the past by the paucity of studies that include broadleaved tree species, which are, in fact, quite common in various rockfall-prone environments. In this study, we test the sensitivity of two common, yet unstudied, broadleaved species — Quercus pubescens Willd. (Qp) and Acer opalus Mill. (Ao) — to record rockfall impacts. The approach is based on a systematic mapping of trees and the counting of visible scars on the stem surface of both species. Data are presented from a site in the Vercors massif (French Alps) where rocks are frequently detached from Valanginian limestone and marl cliffs. We compare recurrence interval maps obtained from both species and from two different sets of tree structures (i.e., single trees vs. coppice stands) based on Cohen's k coefficient and the mean absolute error. A total of 1230 scars were observed on the stem surface of 847 A. opalus and Q. pubescens trees. Both methods yield comparable results on the spatial distribution of relative rockfall activity with similar downslope decreasing recurrence intervals. Yet recurrence intervals vary significantly according to tree species and tree structure. The recurrence interval observed on the stem surface of Q. pubescens exceeds that of A. opalus by N20 years in the lower part of the studied plot. Similarly, the recurrence interval map derived from A. opalus coppice stands, dominant at the stand scale, does not exhibit a clear spatial pattern. Differences between species may be explained by the bark thickness of Q. pubescens, which has been demonstrated to grow at twice the rate of A. opalus, thus constituting a mechanical barrier that is able to buffer low energy rockfalls and thus can avoid damage to the underlying tissues. The reasons for differences between tree structures are related to the clustered coppice-specific spatial stem distribution in clumps that could result on one hand in bigger gaps between clumps, which in turn decreases the probability of tree impacts for traveling blocks. On the other hand, data also indicate that several scars on the bark of coppice stands may stem from the same impact and thus may lead to an overestimation of rockfall activity.

Summary 1 Spatial patterns of seedling establishment have been shown to be largely affected by differences at the microhabitat scale. However, it is far from clear whether such differences are consistent both in space and time, and how they influence the spatial structure of plant populations. 2 We analyse the spatiotemporal variability in microhabitat quality for seedling emergence and survival of the Mediterranean tree Acer opalus ssp. granatense , examining seedling dynamics at the microhabitat scale in two maple populations intermingled in pine forests and two established on stony slopes during three consecutive years with different climatic conditions. 3 Seedling establishment varied markedly between microhabitats. In general, seedlings benefited from the presence of pre-established vegetation, with lower emergence and survival of maple seedlings in open interspaces than under adult maples, non-conspecific trees and shrubs. 4 However, the quality of most microhabitats depended on both habitat type and year. Emergence and survival under adult maples, heterospecific trees and in open interspaces was higher in forest than in stony-slope populations, and increased significantly with summer rainfall. Shrubs, on the contrary, showed relatively high values of seedling emergence and survival at all sites and in both dry and wet years. Consequently, the benefits of living under shrubs were comparatively greater at lower precipitation levels. 5 The different microhabitats found in heterogeneous landscapes such as Mediterranean forests vary, over relatively large spatiotemporal scales, in quality for seedling establishment. Shrubs showed the highest consistency in patterns of both seedling emergence and survival. This finding, together with the predominance of dry years in Mediterranean areas, may explain why Acer opalus ssp. granatense has a stable spatial distribution at a geographical scale with most saplings associated with shrubs. Spatiotemporal patterns of seedling dynamics at the microhabitat scale may cascade through later demographic stages, eventually impacting the spatial structure of plant populations.

Risk memory at long-term and inventories, especially geomorphologic, have proven to be limited in urbanized areas where the vulnerability associated increases in proportion to urbanization. Rockfall numerical models need to be parametrized and then validated by known events. Tree-ring analyses allow reconstructing past rockfall activity on forested slope at an annual scale. Yet, the reconstruction of rockfall chronologies has been hampered by the paucity of studies that include broadleaved species. This study is going to define the rockfall impacts sensibility of two common and unstudied broadleaved species: Quercus pubescens (Pubescent Oak) and Acer opalus (Italian Maple). The approach is based on the systematic mapping of trees and the counting of visible scars on the stem surface of both species. Data are presented from a site in the Vercors massif (French Alps), where rockfalls are frequently detached from Valanginian limestone marl cliff. A total of 1230 scars were observed on the stem surface of 847 A. opalus and Q. pubescens. Both species present similar spatial distributionof relative rockfall activity with similar downslope decreasing recurrence intervals. By comparing recurrence interval maps obtained from both species and two different tree structures (single trees vs coppice stools) maps based on the Cohen Kappa coefficient and the Mean Absolute Error, this study demonstrate that (i) recurrence intervals vary significantly according to tree species and tree structure; (ii) the recurrence interval observed on Q. pubescens exceeds that of A. opalus of > 20 year in the lower part of the studied plot; and (iii) A. opalus coppice stools do not exhibit a clear spatial pattern. These findings may be explained by the bark thickness and structure of Q. pubescens thougher than A. opalus which constituting a mechanical barrier buffering low energy rockfalls, and avoiding injury to underlying tissues. This master thesis prove the reliability of Q. pubescens and A. opalus for reconstructing rockfall activity and open methodological and practical reflexions on the use of tree-rings and modelling approach for regulatory hazard zoning., La mémoire du risque à long terme et l’inventaire des aléas, notamment géomorphologiques, apparaissent comme encore insuffisants dans les zones où la vulnérabilité s’accroît avec l’urbanisation. Les modèles numériques de chutes de pierres ont besoin d’être paramétrés et validés à partir d’événements connus. Sur les versants forestiers, la dendrogéomorphologie permet la reconstitution de l’activité passée des chutes de pierres à l’échelle annuelle. Néanmoins, la reconstitution des chronologies de chutes de pierres est limitée par le manque d’études qui utilisent des essences feuillues. Cette étude définit la sensibilité aux impacts de pierres en chute de deux espèces feuillues communes mais jamais étudiées : le chêne pubescent (Quercus pubescens) et l’érable à feuilles d’obier (Acer opalus). La méthodologie se base sur la cartographie systématique des arbres et le décompte des blessures visibles sur la surface des troncs de chaque espèce. Les données sont issues d’un site d’étude localisé dans le massif du Vercors (Alpes françaises), où les chutes de pierres proviennent d’un escarpement de calcaire marneux du Valanginien. Un total de 1230 blessures a été observé sur la surface de 847 A. opalus et Q. pubescens. Les deux essences présentent des distributions similaires de l’activité relative des chutes de pierres avec une décroissance amont-aval de l’intervalle de récurrence similaire. Par comparaison des cartes d’intervalles de récurrence, obtenues pour les deux essences et les deux types de structure spatiale des tiges (tiges uniques et cépées) et se basant sur le coefficient kappa de Cohen et sur l’erreur moyenne absolue, cette étude démontre que (i) les intervalles de récurrence varient significativement en fonction de l’essence et de la structure spatiale des tiges ; (ii) l’intervalle de récurrence observé sur A. opalus est inférieur de 20 ans à celui de Q. pubescens dans la partie inférieure de la parcelle d’étude ; et (iii) A. opalus en cépée ne révèle pas une emprise spatiale immédiatement intelligible. Ces résultats peuvent être expliqués par l’épaisseur et la structure d’écorce de Q. pubescens, différentes de celles d’A. opalus et qui constituent une barrière mécanique atténuant les chutes de pierres de faible énergie évitant ainsi l’endommagement des tissus internes. Cette étude prouve la fiabilité de Q. pubescens et d’A. opalus pour la reconstitution de l’activité des chutes de pierres et ouvre des réflexions méthodologiques et pratiques sur l’usage des techniques de dendrogéomorphologie et de modélisation du processus pour le zonage réglementaire de l’aléa « chute de pierres ».

13 pages, 3 figures, 2 tables, 57 references. I am most indebted to Regino Zamora and José María Gómez for their invaluable intellectual and logistical support during this study. I thank the Consejería de Medio Ambiente (Junta de Andalucía) and the Directors of the Sierra Nevada National Park and the Sierra de Baza Natural Park for permission to do fieldwork. Many thanks also to Sergio de Haro, Elena Baraza and José Antonio Hódar for field assistance. David Nesbitt improved the English version. This research is part of REDBOME (www.ugr.es/~redbome/) and GLOBIMED (www.globimed.net) networks on forest ecology., 1. Plant recruitment is a multiphase process that takes place in environments that are heterogeneous in space and time. In this work, I analyse how environmental heterogeneity in Mediterranean forests affects dynamics of early recruitment at different scales, using the wind-dispersed tree Acer opalus subsp. granatense as a case study. 2. Seed dispersal and viability, post-dispersal predation, seedling emergence and seedling and sapling survival were evaluated in different habitats (regional scale) and microhabitats (local scale). Simultaneously, a review of the literature on spatial dynamics of plant recruitment in Mediterranean systems was conducted to look for general patterns and investigate their fit to the Acer system. Nineteen woody and herbaceous species were included in the review. 3. At the regional scale, Acer recruitment dynamics strongly converged among sites of the same habitat. This was mainly due to large seedling emergence and survival differences among habitats. Although most of the studies reviewed analyzed only one site per habitat type, they also support strong regional variation (either site- or habitat-specific) in recruitment patterns. 4. At the local scale, Acer recruitment was microhabitat-specific, a result shared by almost all the reviewed species independently of their life form and dispersal syndrome. This was mostly due to spatial differences in seed arrival (higher under conspecifics) and seedling survival (higher under nurse shrubs). 5. Spatial discordance among seed rain and recruitment was found in 60% of the reviewed species at the regional scale, and in 67% at the local scale. Acer results supported this predominant lack of concordance. Discordance among seed rain and recruitment suggests that regeneration is largely limited by safe sites than by seed availability. Because seedling survival was the limiting process with a larger impact on the magnitude and spatial pattern of recruitment, safe sites might be defined as those where seedlings have a higher survival probability. 6. Synthesis : This study indicates that the influence of seed dispersal on the spatial patterns and demography of plant species could be limited in heterogeneous and stressful environments (as are found in the Mediterranean), where recruitment is restricted to a small fraction of the landscape. If we are to preserve the distribution and abundance of Mediterranean species in the face of environmental changes, we need to explicitly consider the strong patch-specificity that characterizes their recruitment process at all scales., This study was supported by a grant PFPU-MECD to L.G.A., the Andalusian government grant (PAI) rnm-220 and by the coordinated Spanish MEC projects HETEROMED (REN2002-04041-CO2-01/GLO) and DINAMED (CGL2005-05830-C03-03).

10 pages, 3 figures, 3 tables, 55 references., Most of our knowledge regarding ontogenetic niche shifts in plants has been derived from studies involving only two or unconnected life stages. Approaches covering a broader range of different life stages are still needed to fully understand the implications of ontogenetic niche shifts for plant regeneration dynamics. We investigated ontogenetic shifts in the endangered Mediterranean tree species Acer opalus ssp. granatense (A. opalus) comparing the environmental characteristics of individuals of different ages with those of a random sample of available microsites. In addition, since herbivory could be a limiting factor, herbivory damage was quantified. Differences in environmental characteristics between locations of individual plants and randomly selected points became larger with plant age, suggesting that the regeneration niche of A. opalus shifts during ontogeny, undergoing a contraction. The presence of shrubs and adult trees, the depth of the litter layer, and herbivory were the main factors influencing these changes. A. opalus can germinate in all available microhabitats its seeds can reach, but saplings establish and grow only in a subset of microhabitats, which represent a change in tolerance to extrinsic factors. Old saplings establish under the canopy of shrubs, far away from tree cover that could block light required in the oldest stage. Therefore, temporal changes in the nature and strength of plant–plant interactions are also occurring. The ecological concept of niche shifts reveals the microsites with higher probabilities of long-term sapling survival of A. opalus: shrub cover involves an array of environmental changes crucial for the successful establishment of A. opalus saplings under stressful Mediterranean conditions, from microhabitat amelioration to herbivory protection., This study was supported by the Grant FPI-MEC to JLQ (BES-2003-1716), and by the coordinated Spanish CICYT projects HETEROMED (REN2002-04041) and DINAMED (CGL2005-05830). LGA was supported by a postdoctoral fellowship from the University of Granada and by a Fullbright postdoctoral fellowship (FU2004-1288) from the Spanish Ministerio de Educación y Ciencia (MEC). FTM was supported by Fullbright (FU2003-0398) and Ramón y Cajal research fellowships from MEC. This research is part of the REDBOME (http://www.ugr.es/~redbome/) and GLOBIMED (http://www.globimed.net) networks on forest ecology.

4 paginas, 2 tablas., An enrichment protocol was used to isolate and characterize microsatellite loci in Acer opalus, a Mediterranean tree species. Highly polymorphic microsatellite loci were required for paternity analyses in a population of this species. Eight microsatellite loci were amplified and a total of 87 alleles were detected in a sample of 142 individuals from one population, allowing the identification of each individual with a unique multilocus genotype. The paternity exclusion probabilities varied from 0.261 for locus Aop820 to 0.806 for locus Aop450, and the parent-pair exclusion probabilities varied from 0.433 for Aop820 to 0.940 for Aop450. The cumulative probabilities of exclusion for paternity and parentage of the eight loci were both higher than 0.999, supporting the usefulness of these microsatellite loci for future paternity and parentage analyses in A. opalus. Cross-species transferability was also assayed, supporting their potential use in other eight Acer species., We thank B. Ortiz-Rivas for his assistance in laboratory work. This study has been supported by a Ministerio de Educación y Ciencia/Comisión Interministerial de Ciencia y Tecnología MEC/CICYT (REPROFOR AGL2005-07440-C02-02/FOR) project grant to M. Verdú. J.G. Segarra-Moragues was supported by a Itinerario Integrado de Inserción Profesional (I3P) postdoctoral grant from the Spanish Consejo Superior de Investigaciones Científicas (CSIC); G. Gleiser was supported by a FPU PhD grant from the Spanish Ministerio de Educación y Ciencia.

12 pages, 6 figures, 6 tables, 58 references., The ecophysiological mechanisms underlying plant–plant interactions and forest regeneration processes in Mediterranean ecosystems are poorly understood, and the experimental evidence for the role of light availability in these processes is particularly scant.We analyzed the effects of high and lowirradiances on 31 ecological, morphological and physiological variables in saplings of four late-successional Mediterranean trees, two deciduous (Acer opalus subsp. granatense (Boiss.) Font Quer & Rothm. and Quercus pyrenaica Willd.) and two evergreen (Pinus nigra Arnold subsp. salzmannii (Dunal) Franco and Quercus ilex L.), which coexist in mature montane forests. Species differed in both their capacity to withstand high radiation and in their shade tolerance. The two deciduous species were the least tolerant to high radiation, exhibiting both dynamic and chronic photoinhibition in full sunlight, with severe implications for gas exchange and photosynthetic performance. Excess light severely limited the survival of A. opalus subsp. granatense, even minor reductions of excessive radiation (from full sunlight to 80% sunlight) being crucial for sapling survival. Among species, P. nigra was the most tolerant of high irradiances but showed the poorest shade acclimation. Interspecific differences in the mechanisms of response to light provide a partial explanation of the differential regeneration patterns previously reported for these species, with shadetolerant plants (i.e., deciduous broadleaf species) benefiting the most from associations with nurse plants.We conclude that light availability is an important environmental factor defining the regeneration niche of Mediterranean woody species., This study was supported by a PFPU-MECD grant to L.G.A, and projects REN2001-4552-E and HETEROMED REN2002-04041-CO2-01/ GLO from the Spanish Ministry of Science and Technology (MCYT). This collaborative research was favored by the thematic network GLOBIMED and also supported by MCYT.

6 páginas, 2 figuras., Dormancy in seeds of Acer opalus is shown to be mainly caused by the seed coats, although a slight embryo dormancy exists in fresh seeds. The ability to germinate after drying indicates that seed storage behaviour is orthodox. Recalcitrant seeds were heavier than orthodox seeds not only within section Acer but also within the whole genus after statistical control of phylogeny, through a phylogenetic ANOVA with data from two different Acer phylogenies. An evolutionary change from orthodox to recalcitrant behaviour is postulated for genus Acer, but this change appears not to have been accompanied by a change in seed dormancy, at least in the taxonomic section in which Acer opalus belongs., We would like to thank Patricio García-Fayos and Hugh W. Pritchard for their suggestions and helpful comments and Lorena Gómez, Regino Zamora and José M. Gómez for the useful data concerning germination response in the field. Funding was provided by a Ramón & Cajal grant from the Spanish Ministerio de Ciencia y Tecnología to Miguel Verdú.

6 páginas, 2 figuras, 1 tabla., 1. Theory predicts that plants that achieve fitness more through male function may be less tolerant of herbivory than those that achieve fitness through the female function. We tested this hypothesis by measuring the degree of infection and damage inflicted by the gall-forming eriophyid mite Aceria macrorhynchus on three different sexual morphs (males, protandrous bisexuals and protogynous bisexuals) of the Mediterranean tree Acer opalus., 2. The dependence of each morph on male function, estimated by registering gender changes over 5 years and quantifying male function, decreased in the order males, protandrous, protogynous., 3. The same decreasing order was found in the degree of gall infection produced by the mite, and in the reduction of photosynthetic rates and shoot growth, but not in the carbon-isotope discrimination caused by the mites., 4. Mites attack the morphs of A. opalus that rely more on the male function more often and more harmfully than they do other morphs. Male-biased herbivory is a selective force that could have been driving the separation of sexes in the genus Acer., We especially thank T. L. Ashman, D. C. Freeman and A. Traveset for their comments on the manuscript. I. Pérez-Moreno identified the mite. P. Cámara, S. Cosín, I. Gimeno and D. Montesinos helped in data collection. J. L. Ferrándiz and the staff of the Park gave us permission to work in the Parque Natural de la Font Roja. The project 1FD97-0551 supported this research. M.V. was granted with contracts of the Reincorporación de Doctores y Tecnólogos del Ministerio de Educación y Ciencia and Programa Ramón y Cajal del Ministerio de Ciencia y Tecnología during this study.

The existence of large databases is fundamental to improve ecological and phytogeographical information to build a ‘natural’ syntaxonomic scheme. In different parts of Europe, deciduous forests have already been well studied and their phytosociological meaning interpreted at regional level, nevertheless a broader scale approach is often missing. To define the thermophilic and mesophilic oak deciduous forests of Southern Europe there are several syntaxonomical proposals at higher ranks, that show differences in their ecological significance. Several Authors use the Querco-Fagetea class by which the differences between oak, mixed and beech forests are expressed at the level of order and alliance. Despite the clear link between the Italian and Balkan Peninsula, the Apennines maintain strong links with the forest vegetation of Central Europe, interpretable only within the QuercoFagetea class. In Italy phytosociological studies focused on deciduous oak forests have a relative recent tradition compared with other countries. In particular there are a great number of local contributions, while there are only few contributions that tackle syntaxonomical issues at a broader, peninsular level. For these reasons the aim of this database is to collect releves of oak forests belonging to the Quercetalia pubescenti-petraeae and Fagetalia sylvaticae orders to perform numerical analyses and classification. Thermophilous and thermo-mesophilous oak forests are dominated by various species such as Quercus cerris, Q. pubescens, Q. frainetto, Carpinus betulus, Carpinus orientalis, Ostrya carpinifolia, Fraxinus ornus and Acer opalus obtusatum. The present project is based on selected published (and unpublished) releves recorded according to the Braun-Blanquet approach and stored in a TURBOVEG database. At present 1,600 releves of oak forests vegetation surveyed in Peninsular Italy are stored in the Deciduous Oak Forests Database of the Italian Peninsula (GIVD ID EU-IT-006). The future goals are to determine whether the variation in species composition follows a geographical pattern, to test the real ecological characteristics of the associations recognised by phytosociological studies and to identify which diagnostic species can be used for different types.

International audience; Plant water relationships and hydraulic characteristics were measured for two species of the genus Acer that co-occur with Fraxinus excelsior, but differ in their habitat preference with respect to soil moisture: Acer pseudoplatanus is restricted to wet habitats, whereas Acer opalus occurs on drier sites. The data obtained showed significantly lower hydraulic conductance and lower vulnerability to embolism in the drought-tolerant species, Acer opalus, than in the water prefering species Acer pseudoplatanus. Similar differences in hydraulic conductance and xylem vulnerability to embolism were also found under dry acclimated conditions for Fraxinus excelsior trees, indicating that the hydraulic differences observed might be attributable to the contrasting soil water conditions of the sites. The possible physiological and ecological significance of such differences are discussed, in relation to habitat preference and the distribution of each species.; Étude comparée des relations hydriques et des caractéristiques hydrauliques chez Fraxinus excelsior, Acer pseudoplatanus et Acer opalus dans différents milieux secs et humides. Ce travail concerne l'étude des relations hydriques et la détermination des caractéristiques hydrauliques chez deux espèces du genre Acer, présentes fréquemment dans les espaces naturels en compagnie de Fraxinus excelsior, mais différant dans leur mode de distribution en fonction de la disponilité de l'eau du sol : Acer pseudoplatanus se rencontre sur des sols bien alimentés en eau, Acer opalus a une préférence marquée pour les milieux secs. Les résultats obtenus montrent, chez Acer opalus, l'espèce tolérante à la sécheresse, que la conductance hydraulique et la vulnérabilité à la cavitation sont moins fortes que chez Acer pseudoplatanus, l'espèce des zones humides. Des modifications identiques de la conductance hydraulique et de la vulnérabilité à la cavitation s'observent également chez Fraxinus excelsior pour l'espèce acclimatée aux milieux secs, ce qui semble indiquer que ces changements des caractéristiques hydrauliques pourraient être associés aux conditions hydriques des milieux. Ces résultats sont analysés au plan physiologique et écologique en relation avec le mode de distribution de ces espèces dans leur environnement respectif.

Evidence is presented for dynamic successions in the Provence on the basis of a multivariate analysis, of a very large sample. Different phases in the Quercus suber series on silicious substrate are shown. Also the evolution of the vegetation groupings on Ventoux and Sainte-Baume mountains on calcareous substrate and at different levels in the zonation is specified. The succession of the grasslands is as follows: Isoetes and Nasturtium groupings, Serapias, Lotus and Trifolium, then Vulpia and Aira groupings, and finally Helianthemum guttatum grasslands, preceding the shrub groupings: Cistus ladaniferus, then Cistus albidus and Cistus monspeliensis. Then follow either Erica and Calluna maquis or Quercus suber formations. On Mont Ventoux, the stages of degradation of the Quercus pubescens forests are Aphyllantes and Thymus vulgaris grasslands, and Buxus sempervirens and Genista scorpius scrubs. On the oromediterranean level, the transition from Avena setacea and Galium villarsii grasslands, then Ononis caenisia grasslands to Pinus uncinata forests is demonstrated. The development of reforestation is predicted on the basis of the floristic composition of the previous stages. On Sainte-Baume Mountain, the Quercus pubescens supramediterranean series is formed by the following stages: low scrubs of the Lavandulo-Astragaletum, and Prunus mahaleb and Phillyrea media, Acer monspessulanum groves, and forests with prevailing Quercus pubescens. The succession on rocky traverses and crests is slightly different. The first stages are Sesleria grasslands and the later ones are woodland groupings of Tilia platyphyllos, Acer opalus and Ilex aquifolium.