:: E. DODINET Editorial Editorial Paru dans Acta Botanica Gallica, 2015, 162 (1), pp. 1-2. Anglais :: E. DODINET List of reviewers Paru dans Acta Botanica Gallica, 2015, 162 (1), pp. 3-4. Anglais :: R. EL MOKNI, G. DOMINA, H. SEBEI & M. HEDI EL AOUNI Taxonomic notes and distribution of taxa of Orobanche gr. minor (Orobanchaceae) from Tunisia Paru dans Acta Botanica Gallica, 2015, 162 (1), pp. 5-10. Anglais Abstract New records for the flora of Tunisia and, in part, for North Africa of taxa of Orobanche sect. Orobanche subsect. Minores (Beck) Teryokhin, are reported. These records come from field research carried out between 2010 and 2014 in the Kroumiria region in northwestern Tunisia and herbarium studies. Infraspecific taxa and chorological data about the identified taxa (Orobanche amethystea Thuill., Orobanche canescens C. Presl, Orobanche hederae Duby, Orobanche litorea Guss., Orobanche minor Sm. and Orobanche pubescens d’Urv.) are reported. Literature data on host and distribution are also revised. Orobanche litorea is new to North Africa, and O. canescens has been confirmed for North Africa more than 100 years after the only known collection. Orobanche hederae and O. pubescens are new to Tunisia.
:: S. KÖSTEKCI & T.ARABACI Cypselar morphology of Carduus L. (Asteraceae) taxa in Turkey and its taxonomic implications Paru dans Acta Botanica Gallica, 2015, 162 (1), pp. 11-26. Anglais Abstract Cypselar morphology of 24 taxa including 16 species and eight subspecies of the 29 Turkish Carduus L. (Asteraceae) taxa (belonging to 17 species) were examined by stereomicroscope and scanning electron microscope. In this study, nine qualitative characters (cypselar shape, symmetry, kurtosis, surface ornamentation and different features of cypselar surface cells) and five quantitative characters (cypselar length and width, umbo length and width, ring diameter) were examined. Macromorphological studies revealed oblanceolate, narrowly obovate, narrowly oblong to oblong cypselar shapes with striate or furrowed surface. Based on scanning electron microscopic investigation of cypselar surface, the studied taxa were divided into five main types: scalariform, scalariform-ribbed, scrobiculate-ribbed, scrobiculate and scrobiculate-foveolate. An identification key of studied species based on cypselar morphology has been provided. The results indicate that cypselar features can be used as diagnostic taxonomic characters in examined Carduus species.
:: V. BONNET, N. FORT, C. DENTANT, R. BONET, P. SALOMEZ & I. TILL-BOTTRAUD Méthodologie de suivi des espèces végétales rares mise en place par un réseau d’acteurs de la conservation A methodology for monitoring rare plant species designed by a network of conservation stakeholders Paru dans Acta Botanica Gallica, 2015, 162 (1), pp. 27-36. Français Résumé Devant le besoin croissant de données sur la dynamique des populations d’espèces rares aux échelles régionales, nationales et européennes, le Réseau Alpes-Ain de Conservation de la Flore, qui regroupe des acteurs de la conservation de la flore sur les régions Provence-Alpes-Côte d’Azur et Rhône-Alpes, a mis en place des protocoles emboîtés (niveaux) de suivi d’espèces pour différentes échelles spatiales. Chaque niveau de suivi répond à un objectif particulier et correspond à un protocole de suivi commun à l’ensemble des acteurs du Réseau. L’article présente le protocole de suivi défini au niveau « territoire ». Son objectif est de mettre en évidence les régressions ou progressions d’une espèce à l’échelle supra-régionale. Les variables utilisées pour ce suivi sont simples et facilement reproductibles. Il s’agit de l’aire de présence et d’absence de l’espèce sur un site donné, et d’une variable de fréquence d’occurrence de l’espèce dans son aire de présence. Cette méthode répond bien aux besoins actuels de l’Europe en matière d’évaluation des populations d’espèces végétales dans le cadre de la Directive Habitats-Faune-Flore (Directive 92/43/CEE).
Abstract There is an increasing need for data on the patterns of population changes for rare species at the regional, national and European scales in the context of the Natura 2000 reporting on the state of species’ conservation. This reporting requires the use of the same protocol over a whole region or country with the major constraint that it has to be shared by a large array of conservations and monitoring structures. The protocol has therefore to be both precise and reproducible but also simple enough to be used over a large number of sites and years, and has moreover to be accepted by various conservation structures. In this aim, the Alps-Ain flora conservation network (Réseau Alpes-Ain de Conservation de la Flore), a network composed of flora conservation stakeholders for 2 regions, Provence-Alpes-Côte d’Azur and Rhône-Alpes, set up a series of nested protocols to monitor populations at different spatial scales (levels). Each monitoring level is set up to answer to a specific aim and corresponds to a protocol shared by all the network actors. The first level, detailed below, is defined for the regional scale (“territory” level) with the site as observation unit. The second level aims at identifying if in a specific site (“station”) a population is stable, expanding or regressing and if natural or anthropic factors can explain this dynamics. The observation unit is a plot or a transect and the variables measured are frequencies or numbers and environmental parameters. The third level is an individual-based survey (“individu”) and aims at understanding the demographic processes affecting a population. The observation unit is here the individual plant. The link between the 3 levels is described in Figure 1. The “territory” level protocol was developed over several years of discussions and in situ tests on several species (Table 1). Its aim is to identify increases or decreases of species’ size at the scale of the region. The variables used for this monitoring are simple and easily reproducible: area of presence and frequency. During the process, we realized that even a simple protocol could not be applied to a large range of species. We therefore propose some variations on a common methodological base, depending on the biology of the species (longevity, clonality, dormancy, size of individuals…). An originality of the protocol is to note the non-detection of the species in a given point at a given time to be able to document the expansion or the regression of the species in the site. A first step therefore consists in defining the zone in which the species will be looked for, the prospection zone (ZP). This zone should orrespond as much as possible to the potential habitat of the species and has to remain constant over time. Within this zone, the area of presence (AP) is determined using the envelope formed by the GPS points where the species is found. Population size is then estimated as the frequency of occurrence by contact-points along at least two transects positioned so as to take into account the environmental heterogeneity of the site (see Figure 1). For species that have very variable population sizes and distributions, the transects should be representative of the AP; for species with very stable populations, we recommend fixed transects to reduce year-to-year and spatial variations, however managers are free to choose the location of the transects. At least 100 points are taken for each transect in order to have a robust estimate of the frequency of occurrence. For species with low ground cover, we suggest replacing the contact-point by contact-areas, i.e. small plots positioned similarly to the points along the transects. The areas of the plots have to be decided in advance and should not change over time. The aim is to avoid extreme frequency values (close to 0 or 1) in order to be able to detect an increase or a decrease in population size. Each prospection zone corresponds to one data point. At the regional scale, the population is represented by the ensemble of the ZPs. To have a good estimate of the population size and its dynamics, the ZPs should correspond to a random or a stratified sample of all the existing sites. This is however difficult and in practice, the ZPs of the survey are the ones for which an organism can commit itself. The RAACF then has to make sure that the sample of ZPs is representative of the species’ distribution. The frequency of the survey depends on the biological characteristics of the species. For perennial species we suggest a time step of 3 to 5 years in the absence of catastrophic events. For annual or dormant species, the survey should be performed over 3-5 consecutive years in order to have a reliable estimate of AP and size and to smooth out the inter-annual (normal) fluctuations, and then repeated 3-5 years later. A web-service database was developed by the network to ensure the aggregation of the data. This method is a practical answer to the EU requirements in terms of assessment of populations of plant species in the framework of the EU Habitats Directive (Council Directive 92/43/EEC).
:: C. NETO, J. P. FONSECA, J. C. COSTA & F. BIORET Ecology and phytosociology of endangered psammophytic species of the Omphalodes genus in western Europe Paru dans Acta Botanica Gallica, 2015, 162 (1), pp. 37-54. Anglais Abstract Omphalodes kuzinskyanae Willk. is an endangered annual plant of the family Boraginaceae, endemic to a narrow coastal area in the Lisbon region (Portugal). Omphalodes littoralis Lehm. occurs in northwest Spain (subsp. gallaecica) and northwest France (subsp. littoralis). Three approaches were used to assess the ecological requirements of O. kuzinskyanae: (1) physical and chemical characterization of their habitat soil; (2) phytosociological analysis; (3) comparison of several life history parameters under different light conditions. Germination experiments were conducted to evaluate seed dormancy. The results show that O. kuzinskyanae occurs in thin sandy soil with a substantial amount of organic matter and clay, mostly over limestone pavements. Phytosociological analysis shows that O. kuzinskyanae occurs both in sciophytic and heliophytic communities. Life history comparisons demonstrated that this plant has a strong preference for sciophytic conditions: under strong shade, plants have a higher survival rate, attain a greater height and width, and produce approximately nine times more seeds than in sunny conditions. In contrast with O. kuzinskyanae, published data on O. littoralis indicate that this species occurs in heliophytic conditions. This group of Omphalodes is possibly limited both in geographical distribution and habitat by its vulnerability to hydric stress. Scenarios are discussed that can explain the extensive gap separating the present ranges of the two species and their ecological differences. We propose two new syntaxa: Linario arenariae-Omphalodetum littoralis, Geranio purpurei-Galietum minutuli omphalodetosum kuzinskyanae.
:: P. MINISSALE & S. SCIANDRELLO The sabulicolous therophytic associations in Sicily: new insights through the statistical approach, stressing the continuum versus discrete model of plant communities Paru dans Acta Botanica Gallica, 2015, 162 (1), pp. 55-78. Anglais Abstract This study presents an updated syntaxonomic review of the annual psammophilous plant communities from coastal dunes and inland territories of Sicily. A total of 301 relevés were collected. The relevés data were analysed using classification (WPGMA, similarity ratio) and ordination methods (detrended correspondence analysis and principal component analysis). Eighteen plant communities were recognized, four of which are described here for the first time (Rostrario littoreae-Tuberarietum villosissimae, Filigini asterisciflorae-Loeflingietum hispanicae, Astragalo kamarinensis-Coronilletum repandae, Sileno coloratae-Ononidetum variegatae cutandietosum maritimae). The surveyed associations are ascribed to the following orders: Cutandietalia maritimae (annual associations of semi-fixed dunes) and Malcolmietalia (inland sandy soil communities). Moreover, for this latter order, a new alliance, Filagini asterisciflorae-Linarion humilis, that groups the therophytic communities from fossil dunes and deep sandy soils of the inland of the Sicily, is proposed. Another aim of this study is to check and compare the discrete model of plant community against the continuum model along environmental gradients.
:: I. GNONLONFOUN, R. GLÈLÈ KAKAÏ, V.K. SALAKO, A.E. ASSOGBADJO & A. OUÉDRAOGO Structural analysis of regeneration in tropical dense forest: combined effect of plot and spatial distribution patterns Paru dans Acta Botanica Gallica, 2015, 162 (1), pp. 79-87. Anglais Abstract This study assessed the combined effect of the size and shape of inventory plots on the analysis of the density and diameter structure of saplings and juvenile trees. Thirty square plots of 400 m² were randomly laid out and each one was divided into 400 quadrats of 1 m². Stem number of recruits was recorded for all tree species and their diameter at breast height was measured in the quadrats. Seven types of subplots with different shapes and sizes were considered by grouping adjacent quadrats of 1 m². The Green index was used to assess the spatial distribution of regeneration and Weibull distribution was applied to model stem diameter distributions. Box–Cox transformations and weighted regression were used to model the relationship between the Green index, the plot patterns and the standard error of the estimation of the regeneration density. The same analyses were applied to model the relationship between the Green index, the plot patterns and the mean absolute error of the shape parameter of the Weibull distribution. The Green index and the plot size had a significant impact on the error of the regeneration density estimation. For clumped distribution of individuals, the plot shape had a significant impact on the error of their density estimation. As for stem diameter distribution, only the plot size had a significant effect on the mean absolute error of the stem diameter structure. The rectangular plots and square plots of 100 m² (14 m × 7 m and 10 m × 10 m) appeared more suitable for an effective structural analysis of woody species regeneration in the tropical dense forest for an aggregated distribution and a random distribution, respectively.
:: F.C. TOVISSODÉ, H.S. HONFO, V.K. SALAKO, C.P. GNANGLÈ, S. MENSAH & R. GLÈLÈ KAKAÏ Population structure of two bamboo species in relation to topographical units in the Republic of Benin (West Africa): implications for sustainable management Paru dans Acta Botanica Gallica, 2015, 162 (1), pp. 89-96. Anglais Abstract A study was carried out in two phytodistricts (Ouémé-valley and Plateau) to assess the population structure of two bamboo species (Oxytenanthera abyssinica (A. Rich.) Munro and Bambusa vulgaris Schrad. ex J.C. Wendl. in two topographical units: plateau and wetlan ds. In each phytodistrict, bamboo stands were randomly selected in each topographical unit for inventory using a 0.25-ha square plot. Structural parameters of bamboos were computed and compared using a Wilcoxon rank test. Spatial distribution of the two bamboos was also assessed using the method of neighbourhood density in relation to a focal point. The observed culm diameter distribution was established for each stand and adjusted to the two-parameter Weibull distribution. Oxytenanthera abyssinica showed the highest culm and clump density values in both wetlands and plateau whereas B. vulgaris showed greater values of mean diameter and dominant height whatever the habitat. Diameter structures of bamboo stands showed a right asymmetric distribution and bamboo spatial distribution was highly aggregative, especially in wetlands. No significant difference in mean relative neighbourhood density between species was noted. However, a significant difference was observed between wetlands and plateau (p < 0.001) indicating strong influence of the topographical units on the relative neighbourhood density of bamboo species. All of these findings are determinants in designing suitable management strategies for bamboo populations in Benin, particularly with the increasing demand to build fish-traps and shelter in the traditional fishing systems “Acadja”.
:: S. RHIZOPOULOU & H. PANTAZI Constraints on floral water status of successively blossoming Mediterranean plants under natural conditions Paru dans Acta Botanica Gallica, 2015, 162 (1), pp. 97-102. Anglais Abstract The water relations of showy laminar floral tissues (petals and tepals) were studied in 20 Mediterranean plants successively blossoming under ambient conditions. The water potential and osmotic potential of floral tissues decline according to the succession of the median day of flowering of the selected plant species. The highest (least negative) value of floral water potential (–0.32 MPa), among the examined species, was measured in petals of Anemone coronaria in March, and the lowest value (–1.25 MPa) in petals of Coridothymus capitatus in June. Low values of water potential of floral tissues coincided with constraints in declining values of osmotic potential at the onset of the dry period in the Mediterranean region; this apparently resulted in a reduction of turgor of floral tissues of Mediterranean plants subjected to water shortage. The reduced osmotic potential was correlated with enhanced soluble sugar content of floral tissues, presumably contributing to the expansion and water status of flowers under water scarcity, by decreasing water requirements.