Showing papers in "Plant Ecology and Evolution in 2011"

The endemic and non-endemic vascular flora of Madagascar updated

Abstract: Background and aims - The Catalogue of the Vascular Plants of Madagascar project aims to evaluate and enumerate the native and naturalized vascular plant flora of Madagascar. In light of the past two decades of intensive collecting and taxonomic work, all relevant published literature and available specimens are being reassessed in order to evaluate the taxonomic status and distribution of the native and naturalized taxa of vascular plants. Here we provide current figures for the total numbers of vascular plants and levels of endemism at the order, family, genus and species levels, comparing them to previous historical counts and analyzing the distribution of the non-endemic element of the flora. Key Results - At the time of writing (April 2010), more than a century after Baron first counted 4,100 species of vascular plants in Madagascar, the Madagascar Catalogue database had registered a total of 14,883 accepted names at all taxonomic levels (64 orders, 243 families, 1,730 genera, 11,220 species and 1,626 infraspecific taxa). Of the 11,220 species of vascular plants in Madagascar, 10,650 (95%) are angiosperms, of which 331 are naturalized introduced species. The remaining accepted indigenous angiosperm species total 10,319, of which 8,621 (84%) are endemic to Madagascar (82% endemism for all indigenous vascular plants). Among the 1,698 non-endemic species of indigenous angiosperms, a total of 1,372 (81%) also occur in Africa, of these 654 (39%) are present only in Africa and Madagascar.

Taxonomic changes in C-3 Cyperus (Cyperaceae) supported by molecular data, morphology, embryography, ontogeny and anatomy

Abstract: Background and aims – Recent molecular studies validate a broad definition of Cyperus (Cyperaceae) uniting genera previously scattered in Cyperoideae. First indication of their affinity with Cyperus was obtained through embryography. Cyperus consists of a paraphyletic C3 Cyperus and monophyletic C4 Cyperus. In this study, we aim to check and clarify the putative positions of the segregate genera in C3 Cyperus. Additional information is given and remarks are made on the position of some as yet unplaced species or sections in the C3 Cyperus phylogeny. Methods – Embryos of Cyperus constanzae and C. gardneri were cleared and drawn. Inflorescences of selected C3 Cyperus species were investigated using scanning electron and light microscopy. Histochemical tests were performed to assess the presence of suberin in the ‘corky’ tissue of the nutlets of Cyperus pectinatus. Key results – Embryography not only supports tribal classification in Cyperoideae, it is also phylogenetically informative in C3 Cyperus. Morphology and ontogeny support molecular phylogenetic results suggesting the inclusion of the segregate genera in C3 Cyperus as new sections or in established sections, and confirm the need to broaden the circumscription of some of these sections. Conclusion – Although less diverse than C4 Cyperus, C3 Cyperus includes clades which evolved an exceptional morphological diversity compared to its limited species numbers. The segregate genera Courtoisina (deciduous spikelets), Kyllingiella (spirally-arranged glumes) and Oxycaryum (spirally- arranged glumes and dorsiventrally flattened dimerous gynoecia), and the taxon Anosporum (recognised at sectional, subgeneric or generic level) are here included in C3 Cyperus (= Cyperus subg. Anosporum) as sections or included in an existing section (Kyllingiella is included in Cyperus sect. Leucocephali). A formal taxonomic revision is presented with relevant new names and combinations, synonyms, diagnoses and identification keys.

Deep sequencing of Ptilidium (Ptilidiaceae) suggests evolutionary stasis in liverwort plastid genome structure

Abstract: Embryophyte plastid genomes are, in general, conserved in structure – from 110 to 130 unique (unduplicated) genes arranged across a circular structure comprising two Inverted Repeats (IR) separating a Large Single-Copy (LSC) region and a Small Single-Copy (SSC) region (Raubeson & Jansen 2005). Changes that are found to occur in genome structure (e.g. changes in gene order, gene duplication and loss) are thought to be relatively rare. Plastid genome rearrangements have proved informative in many groups including embryophytes (Kelch et al. 2004, Mishler & Kelch 2009), vascular plants (Raubeson & Jansen 1992), ferns (Stein et al. 1992), Asteraceae (Jansen & Palmer 1987) and recently in mosses (Goffinet et al. 2005, 2007); rearrangements in mitochondrial gene order have also provided supporting information for liverwort relationships inferred from DNA sequence data (e.g. Wahrmund et al. 2008, Knoop 2010). One of the first plastid genomes, from the complex thalloid liverwort Marchantia polymorpha L., was mapped in

Long-term effects of grazing exclusion on aboveground and belowground plant species diversity in a steppe of the Loess Plateau, China

Abstract: Background and aims - Livestock grazing exclusion was widely used to manage degraded grassland ecosystems, but little is known on the effects of long-term grazing exclusion on aboveground and belowground species diversity of the steppe vegetation in China. Material and methods - The species composition of the aboveground vegetation and the soil seed bank were examined on sites after a 25-year grazing exclusion in a typical steppe on the Loess Plateau, NW China. Key results - Results showed that long-term grazing exclusion significantly improved vegetation cover, biomass and aboveground species evenness. Long-term grazing exclusion significantly increased species richness and seed density in the soil seed bank, but significantly decreased belowground species evenness. The seeds were mainly present in the litter and the topsoil (0-5 cm), accounting for about 76% of the total seed number. Exclusion of grazing significantly decreased seed depletion in soil seed bank from April to July as compared to grazed sites. The Sorensen similarity index between aboveground and belowground species composition was low in the typical steppe, and long-term grazing exclusion did not significantly improve this similarity. Conclusion - Our results suggest that long-term grazing exclusion can significantly improve both aboveground and belowground species diversity in the steppe vegetation of the Loess Plateau, but has little or no effect on the similarity in composition between the two compartments.

Coastal dry forests in northern Mozambique

Abstract: Background and aims - The Coastal Forests of Eastern Africa, stretching along the Indian Ocean coastline from Somalia to Mozambique, are considered by Conservation International to be a global biodiversity hotspot - an area of high diversity and endemism under increasing threat. Although the largest remaining extent of these forests is reported to be found in Mozambique, very little is known on their extent, condition and composition here. In addition, the term 'coastal forest' has been used in different ways by different authors. This paper defines and characterises coastal dry forests found in northern Mozambique and assesses their present extent, botanical composition, conservation importance and the threats to these forests. Methods - The study area of 18,150 km2 lies in Cabo Delgado Province in north-east Mozambique, adjacent to Tanzania. Its limits are determined primarily by geological substrate and landform. Four smaller study sites were chosen covering a range of landforms. Manual interpretation of satellite imagery dating from 1999-2002 was used to calculate possible previous and present extent of 'dense vegetation'. Extensive field collecting was used in determining botanical composition and distribution patterns. IUCN Red List assessments were carried out on selected species using distributional criteria. Results - Dry forests similar to those in southern Tanzania are found widely scattered across coastal Cabo Delgado, sitting in a matrix of miombo woodland and other vegetation types. However, forest cover is not as extensive was believed. We calculate that the original extent of 'dense vegetation cover', which includes coastal dry forest, was 6087 km2. Owing to clearance over the last 150 years this is now only 1182 km2, of which perhaps only 400 km2 is moderately-intact dry forest. In this southern part of their range such forests are essentially dry, not moist and mesic, and dominated by a high proportion of deciduous or sclerophyllous evergreen trees. The plant species composition differs significantly from that of the surrounding woodlands. There is a marked change in species composition between forest patches along the coast, and they contain numerous species with restricted global distribution. Since 2003, 68 species new to Mozambique have been recorded from Cabo Delgado in addition to 36 possible new species. Many new records are of species previously only known from south-eastern Tanzania. Previously recorded patterns of restricted distribution and high species turnover between forest patches in Kenya and Tanzania are confirmed. Seven coastal forest species were assessed as Endangered. Regional context and conservation - Coastal dry forests are discussed in relation to the more widespread 'sand forests' of the continental interior of south-central Africa, and shown to have similarities in ecology, species composition, soils and ecology. Very little of the present extent of coastal forests in Mozambique lies within protected areas. The threats to their continued existence in the face of exploitation for timber, agriculture and oil exploration are outlined.

The applicability of Relative Floristic Resemblance to evaluate the conservation value of protected areas.

Abstract: s – It is important to know the contribution of a protected area to global conservation. A new method called ‘Relative Floristic Resemblance’ that uses databased and georeferenced herbarium specimens, is introduced. Its usefulness and applicability to assess the conservation value of protected areas is addressed. Method – This is tested using the collection database of the National Herbarium of The Netherlands (NHN) and species checklists of Gabon and of five national parks in Gabon and the Central African Republic. Results – The method proved to be a valuable instrument for revealing this conservation value, and can even, though with caution, be used for areas where a species list is still incomplete. We conclude that the four Gabonese parks are well chosen and each clearly conserve a different and comparatively unique flora. The Dzanga-Sangha Reserve captures a flora that ranges across a considerable part of the Congo Basin.Key words – Conservation, protected areas, Relative Floristic Resemblance, biodiversity, flora, collection database, Gabon, Central African Republic, Dzanga-Sangha.

Morphology and development of spikelets and flowers in Cyperus and Pycreus (Cyperaceae)

Abstract: Background : Pycreus, Kyllinga, and Queenslandiella cluster together with Cyperus within the Cyperus s. lat. clade, one of the two large clades in Cypereae. However, in contrast with Cyperus, they have laterally flattened pistils/nutlets. Pycreus, Kyllinga and Queenslandiella form morphologically well circumscribed independent genera. In the context of a broader systematic project to work out a well supported, evolution based taxonomy for Cyperus s. lat., we present in this paper general morphological and developmental data of species of Pycreus in comparison with three species of Cyperus, including C. laevigatus with dorsiventrally flattened nutlets. Approach : Freshly collected material was investigated using scanning electron microscopy (SEM) and light microscopy (LM). Special attention was given to spikelet and gynoecial development. Results : SE micrographs of all species studied show an indeterminate rachilla with distichously arranged glumes, each subtending a bisexual flower. In spikelets of C. capitatus and P pumilus, the proximal glume sometimes subtends a lateral spikelet instead of a flower. In the species of Pycreus studied, each flower sits in a cavity formed by the growth of the rachilla, which is congenitally fused with the wings of the glume of the higher, alternate flower. Glumes appear successively, each soon forming a flower primordium in its axil, which develops according to a general cyperoid ontogenetic pattern. In Pycreus, the stigma branches grow out from dorsiventrally positioned primordia. During gynoecium development, a hypogynous stalklet (gynophore) appears in all species studied. Conclusion : In spikelets of Pycreus, the rachilla and wings of the glumes are congenitally fused and consequently develop with epicaulescent displacements of the glumes resulting in typical spikelets with flowers in cavities. In spikelets of Cyperus, a similar though less pronounced development results in spikelets with zigzagging rachilla. The particular positions of the stigma branches in C. laevigatus and Pycreus are explained by the development of the gynoecium from an annular primordium, which facilitates shifts in localisation of the stigma primordia. Though we consider the combination of the typical spikelet ontogeny and the independently originated laterally flattened nutlets to be strong arguments in favour of a genus Pycreus, a phylogenetic confirmation that the taxon is monophyletic is an absolute, until now unfulfilled, condition. Moreover, the consequences for the giant genus Cyperus must be taken in consideration.

Diversity and origin of medicinal exotic flora in Cape Verde Islands.

Abstract: some considerations for the geographic origin of these species. Methods - This study is mostly based on the collection of ethnobotanical data obtained in specimens housed in LISC Herbarium and in available botanical and historical bibliographic data. Key results - A checklist of the exotic medicinal plants of Cape Verde is presented. The use of local flora in folk medicine is common, and 101 exotic naturalized taxa were reported as medicinal in this archipelago. Most of these plants arise from Afrotropical, Neotropical, Palaearctic, or Pantropical regions. Furthermore nineteen non-naturalized exotic taxa, mainly from Neotropical and Oriental regions, were reported as medicinal. Conclusions - This study shows the relevance of historical factors in the determining the composition of the medicinal flora in Cape Verde, namely the importance that the slave trade routes from Africa to the Americas played during the period of the 16th-! 9th centuries. It also allows the recognition and positive valuation of the cultural and biological Cape Verde's patrimony and its sustainable use.

Grazing impact on plant spatial distribution and community composition

Abstract: Background and aims Re-introduction of large grazers in the few remaining natural and semi-natural grasslands are thought to be an effective management tool to prevent dominance of late successional plant species and restoration of plant biodiversity. The main objective of this study was to test whether the introduction of large herbivores retard the succession by reducing the abundance of highly competitive tall species and whether it is accompanied with changes in plant community composition and spatial distribution of plant species. Methods In order to test this hypothesis, we studied the effect of grazing by large herbivores on vegetation at three hierarchical levels: individual plant species, emergent groups of functionally similar herbaceous plant species, and the main gradients of plant community composition. Study sites were thirteen spatially separated, dry coastal dune grasslands in western Belgium and north-western France. Key results Grazing had a predominantly negative effect on high competitive dominant species and led to changes in composition of emergent groups toward less competitive plant species. Additionally, these changes in plant community composition were accompanied with changes in spatial distribution patterns of individual plant species and community richness. Conclusions Our results suggest that the current grazing management applied in these nature reserves is able to prevent the expansion of dominant highly competitive species and establishment of functionally different plant species.

Comparative study of the reproductive ecology of two co-occurring related plant species: the invasive Senecio inaequidens and the native Jacobaea vulgaris.

Abstract: Background and aims – A previous study showed that the visitation rate by pollinators and the seed set of the exotic invasive Senecio inaequidens (Asteraceae) were higher compared to the native relative, Jacobaea vulgaris. The first aim of the present study was to assess if these results could be explained by differences in self-fertility, nectar rewards or floral display between the two species. Moreover, in a second step, we examined if the higher visitation rate on S. inaequidens has a negative effect on the reproductive success of J. vulgaris. Methods – Self-fertility was estimated after self- and cross-hand pollinations. Nectar volume, total sugar concentration and sugar composition were analysed on plants cultivated under controlled conditions. In the field, in order to assess the effect of floral display and impact of the invasive on the pollination success of the native, insect behaviour was assessed by comparing visitation rates, number of visitors per 10 min observation and individual censuses. Floral display (density of capitula per unit area) was artificially modified by clipping or grouping inflorescences in both species.Key results – In terms of self-fertility, seed sets were similarly low after self-pollination (11–12%) for both species. S. inaequidens produced lower amounts of nectar with lower sugar concentration compared to J. vulgaris. No influence of floral display was detected on insect visitation rates. The presence of S. inaequidens did not alter pollinator visits and seed set of J. vulgaris. Conclusions – Other traits need to be investigated to explain the different visitation rates and reproductive success between the two species. The higher seed set of S. inaequidens could be due to a higher outcrossing rate, or more frequent pollinator movements between individuals.

Patterns of hybridization and hybrid survival in the invasive alien Fallopia complex (Polygonaceae).

Abstract: Background Hybridization and polyploidization are considered important driving forces of invasive processes. In the invasive Fallopia spp. complex, hybridization between taxa of various ploidy levels has been experimentally demonstrated. Extensive genetic variation has also been observed among hybrids in the field. However, what makes a certain hybridization event of evolutionary importance is still the subject of speculation considering the invasive potential of hybrid Fallopia. Aims The present study examined landscape scale patterns of interspecific hybridization within the alien invasive Fallopia complex, and tested whether cold winter might act as selective agent for hybrid survival. Methods Eighty seeds per clone were collected from four taxa (F. japonica, F. sachalinensis, F aubertii, and F. x bohemica) and sown in greenhouse and outdoor conditions. Ploidy levels of the resulting seedlings were determined by flow cytometry at early stages of seedling growth and compared to those of mature clones present in the same landscapes. Key results The four studied taxa were involved in interspecific hybridization patterns. Seedlings resulting from hybridization had a large range of ploidy levels, including aneuploid and euploid progeny, and polyploid levels that were not observed in mature clones. Cold winter had a negative effect on germination success. However, a comparison of ploidy levels of seedlings that survived the cold winter with those grown under greenhouse conditions indicated that cold winter was not a significant selection agent for particular ploidy levels. Conclusions Our results stress the importance of interspecific hybridization and polyploidization events in generating invasive hybrids in the alien Fallopia spp. complex. Cold winter represents a selection agent for the survival of early stages of progeny but does not explain the discrepancies in ploidy levels between produced seedlings and currently occurring mature clones.

Scat analysis reveals a wide set of plant species to be potentially dispersed by foxes

Abstract: Background and aims - A good understanding of the ways in which seeds are dispersed within landscapes is essential to plant ecology and conservation. Carnivorous mammals can act as vectors in dispersal through ingestion and subsequent excretion of seeds (endozoochory). The red fox ( Vulpes vulpes L.) is a predatory species that is markedly opportunistic both in habitat and feeding habits, and occurs widespread in many rural and urbanized regions. Due to their high mobility within and among territories, they could contribute to long-distance seed dispersal on a regular basis. To identify the set of species that are potentially dispersed by foxes, we have analyzed scats from the region of Flanders (Belgium) for seeds. Methods - 303 scats were collected throughout the region during two field campaigns. All seeds were isolated from the scats and identified. Key results - Seeds were present in 57% of the scats. If present, the seed number was mostly low (< 10), yet amounted to 1135 in one sample. 77 taxa were identified. 82% of the seeds belonged to woody plant species with fleshy propagules (drupes or berries), Rubus being the most abundant taxon (64%). In addition, numerous dry-fruited woody, herbaceous, and graminoid taxa were found. Autumn samples contained more, and more often, seeds than spring samples. Conclusions - The diversity of plant types and species encountered in scats clearly reflects the opportunistic habits of foxes, with many species consumed from anthropogenic sources such as cultivated plants or waste material. We suspect an inadvertent intake for most of the dry-fruited species, for instance, through the manipulation of prey. Although wild foxes thus appear to excrete a diverse set of species, their role as effective seed dispersers needs further investigation, primarily concerning the fate of these scat-borne seeds.

Revision of the African genus Isomacrolobium (Leuminosae, Caesalpinioideae).

Abstract: Background and aims - The African genus Isomacrolobium (Leguminosae, Caesalpinioideae) is poorly known. Its species are revised. Methods - Normal practices of herbarium taxonomy have been applied to study all herbarium material available, mainly at BM, BR, COI, FHO, G, K, LBV, MA, MO, OXF, P, WAG, and YA. Key results - Twelve species are recognised, including one new one: I. brachyrhachis from Gabon. All the species are confined to the Guineo-Congolian region. A full taxonomic treatment with key to the species is given. The new species is fully illustrated. The fruits, known of nine species, are illustrated as well. Distribution maps of all taxa are provided. Macrolobium ernae, a synonym of I. obanense, is neotypified. For I. graciliflorum and I. leptorrhachis a lectotype is designated.

The geophytic Peperomia subgenus Tildenia (Piperaceae) in the Andes with the description of new species in a phylogenetic framework

Abstract: Background and aims - The pantropical genus Peperomia consists of approximately 1,600 species with an extremely diverse vegetative morphology, especially in the Neotropics. One of the most startling yet overlooked growth forms is the geophytic one, as in subgenus Tildenia. This group occurs in seasonal Neotropical habitats with its highest diversity in Mexico-Guatemala and Peru-Bolivia with few species known from in between these hot spots. Methods - Recent fieldwork in Peru and Bolivia combined with herbarium study and a Bayesian analysis of an aligned sequence matrix of the chloroplast trnK-matK-psbA gene cluster of one accession of each species resulted in new findings within this subgenus. Key results - Fourteen new species are described, discussed in a phylogenetic framework and illustrated. Two species have a wide distribution and occur from central W. Peru to S. Bolivia: the common P. cerrateae and the rare P. parvisagittata. Three endemic species are described from the Amotape-Huancabamba Zone which is particularly rich in tuberous Peperomia species: P. gigantea, P. jalcaensis and P. klopfensteinii. Two species are only known from their type locality in central W. Peru: P. ocrosensis and P. pugnicaudex. Five other Peruvian species are P. ayacuchoana from Ayacucho, P. querocochana from Ancash, wernerrauhii from Huanuco, Peperomia umbrosa from three distant localities, and P. pseudoverruculosa which is relatively common in SE Peru. Two species are Bolivian endemics: the rare P. purpureonervosa from La Paz and the more common P. radiatinervosa from Cochabamba and Chuquisaca. Two former varieties, both endemics of the extreme northern Central Andes, are raised to species rank: P. lilliputiana and P. pseudoperuviana. Finally, basionym rejection and lectotypification are proposed for the widespread and commonly collected tuberous Peperomia in the southern Central Andes: R peruviana. An emended description of Peperomia subgenus Tildenia is also provided.

Patterns of plant species richness of temperate and tropical grassland in South Africa.

Abstract: Grasslands are so called based on the structural facet of this vegetation type. Grasslands are dominated by species of the Poaceae, are mostly one-layered in structure with few trees and shrubs, and are climatically controlled (Mucina & Rutherford 2006). Grasslands occur in both temperate and tropical regions of the world. In southern Africa, Mucina & Rutherford (2006) consider grasslands to be either sub-tropical or temperate. The differentiation between these two grassland types is based on the factors responsible for the maintenance thereof. Tropical grasslands are often regarded as secondary (e.g. fire maintained) or edaphic (e.g. shallow water table) (Matthews et al. 1999). Temperate grasslands are thought to be naturally maintained by subzero temperatures and dry winters, in combination with fire, which prevent colonisation of grasslands by the tropically-derived tree flora of southern Africa (Bredenkamp et al. 2002). South African grasslands are characterised by plant species with special modified underground organs which enable them to escape fire (e.g. geoxylic suffrutices; White 1977) or become dormant in winter (e.g. geophytes; Tainton & Mentis 1984) when growing conditions become unfavourable. Such adaptations are thought to be major mechanisms whereby grassland plants survive severely cold, dry winters and subsequent fires in temperate southern African grasslands (Bredenkamp et al. 2002). Grassland species, especially perennial forbs, are usually quick in responding to the effects of fire and such plants are characterised by profuse flowering and mass seed production (Retief & Van Wyk 2002).

Effectiveness of conservation areas in protecting Shea trees against hemiparasitic plants (Loranthaceae) in Benin, West Africa

Abstract: Background and aims - The Shea tree ( Vitellariaparadoxa), a multi-purpose species highly valued for the oil obtained from its seeds, is commonly maintained in the semi-arid parklands in West African Sudanian zone. However, most of the trees were reported to be infested with mistletoes - plant parasites that may lead to death of the Shea tree and these parasites are known to be directly dispersed on their host by birds. This study therefore aimed to assess the potential effectiveness of protected area on preventing mistletoes proliferation on Shea tree individuals. Methods - Infestations in two habitats: land use area (fields and fallows) and protected area of Pendjari hunting zone were compared. Overall 54 plots of 1 ha (100 m x 100 m) with 487 and 252 individuals of Shea tree in land use and protected area respectively were investigated. ANOVA was used to compare Shea tree infestation rate and infestation degree (with regard to diameter and height of infested Shea tree). Principal Component Analysis (PCA) was performed to correlate the habitats with infestation degree. Key results - The results showed that about 80% of Shea tree individuals were infested in the land use area, this rate was significantly higher than the one of 27.3% observed in the protected area. Overall, heavily infested Shea trees had significantly larger trunks and heights, mainly in land use areas. The land use area was shown to be correlated with high and very high Shea tree infestation degrees while the others infestations degrees (very weak, weak and moderate) were correlated with both areas. Conclusions - Shea trees growing in protected areas are better protected against mistletoe plant parasites than those on cultivated land. Various hypotheses to explain this result are discussed.

Avian fruit ingestion differentially facilitates seed germination of four fleshy-fruited plant species of an Afrotropical forest

Abstract: Background and aims – The effects of gut treatment on the germination of animal-dispersed seeds are critical for the recruitment of many fleshy-fruited plant species, and hence for forest dynamics. However, these effects remain poorly studied especially in African plant species. In this paper, we aim to investigate the effects of gut treatment on the germination capacity and mean germination time of four common plant species of an Afrotropical cloud forest. Methods – We fed Xymalos monospora fruits to its three main avian dispersers to investigate different responses among frugivore species. Next, fruits of four plant species were fed to the most dominant avian disperser, Andropadus milanjensis, to compare responses among plant species. Germination capacity and mean germination time were compared among gut-passed seeds, manually depulped seeds and intact fruits. Key results – Germination of Xymalos monospora seeds was up to nine times more likely and almost twice as fast after bird ingestion compared to intact fruits. An increase in germination capacity, but not in mean germination time, was also detected in four sympatric plant species after ingestion by Andropadus milanjensis. The positive effects of seed ingestion on germination was mainly by fruit pulp removal; only one plant species showed an indication of the combined effect of fruit pulp removal and seed coat scarification on its germination success. Conclusion – Our results indicate that fruit ingestion of four common African forest plant species positively affected germination capacity and mean germination time, and that recruitment success of these plant species may therefore largely depend on their seed dispersers.

A new taxon of the genus Salvia (Lamiaceae) from Turkey

Abstract: Salvia L., the largest genus of Lamiaceae, represents an enormous and cosmopolitan assemblage of nearly 1000 species displaying remarkable variation. It has undergone marked species radiations in three regions of the world: Central and South America (500 spp.), Central Asia/ Mediterranean (250 spp.) and Eastern Asia (90 spp.) (Walker et al. 2004). The latest comprehensive treatment for Salvia in Turkey, Hedge (1982a) recognised 87 species, one of them doubtful. Since 2005, as part of a revision of the genus in Turkey, the authors have described two new species (Ilcim et al. 2009, Celep & Dogan 2010), one new variety (Celep et al. 2009a) and two new records (Celep et al. 2009b, Kahraman et al. 2009). S. aucheri Benth. var. canescens Boiss. & Heldr. has been also raised to subspecies rank (Celep et al. in press). Moreover, two synonyms have been evaluated as valid species (Kahraman et al. 2010). During a field trip near Bozkir, South of Konya (C4, sensu Davis 1965) in the context of this revision, we encountered an unusual population of S. cadmica Boiss. within the area of its known population. The unusual specimens resemble S. smyrnaea Boiss. in terms of their calyx and corolla colour. Later on, similar unusual specimens were found in other populations of S. cadmica in South, West and Central Anatolia. The specimens were identified using the relevant literature (Boissier 1879, Hedge 1972, 1982a, 1982b, Pobedimova 1954) and compared with the types and other representative collections present at ANK, BM, E, G, GAZI, HUB, ISTE, ISTF, K and W herbaria. The objectives of this study are to present the taxonomic revison of S. cadmica and S. smyrnaea analysing their populations by means of field, herbarium and numerical taxonomic methods, to determine the key characters for distinguishing the taxa, to give their amended and expanded description, phenology, ecology and distribution, and to report their pollen and nutlet characteristics.

The genusCoccochondra(neotropical Rubiaceae) expanded

Abstract: Background and aims Several species of shrubs from the Guayana Highlands of Venezuela have been classified in Psychotria subg. Heteropsychotria Steyerm., but are anomalous morphologically in that group. Key results and conclusions These species are here transferred to Coccochondra Rauschert, which now includes four poorly known species that are all endemic to this region. Coccochondra is provisonally considered related to Psychotria L. but is also similar to Ronabea Aubl. The three newly transferred species belong to the new subg. Durifolia (Steyerm.) C.M.Taylor, distinguished from subg. Coccochondra by its five-merous flowers: C. carrenoi (Steyerm.) C.M.Taylor, C. durifolia (Standi.) C.M.Taylor, and C. phelpsiana (Steyerm.) C.M.Taylor.

Variations in CSR strategies along stress gradients in the herb layer of submediterranean forests (central Italy)

Abstract: Material and methods - We collected floristic (species cover in the herb layer) and environmental data about topography, soil and light conditions in 48 sampling plots in a forest landscape of central Italy. We performed canonical redundancy analyses (RDAs) of species and PFT data sets, constrained by photosynthetically active radiation, soil water deficit and soil total nitrogen content. Cover trends of PFTs along the environmental gradients were graphically represented. Key results - All the environmental factors considered did affect ecological strategies in the herb layer, but the variation of both species and PFT data sets were best explained by photosynthetically active radiation. Competitors were favoured by low/intermediate stress levels, with regard to soil water and light intensity. Competitive stress-tolerant ruderals peaked in moderate light stress intensity and in well-watered soils. Stress-tolerant competitors peaked in conditions of strong light and moderate dryness. Conclusions - Spatial variations in environmental conditions and in the related stress gradients determine predictable variations in the functional composition of the herb layer. Therefore, it may be possible to use Grimes's PFTs for assessing environmental constraints and predicting whether a species with a specific strategy is likely to be positively or negatively affected by changes in environmental stress due, for instance, to climate change.

Conservation credit for plant species diversity of small nature reserves in an agricultural matrix

Abstract: We are living in a time of serious diversity decline and species loss (e.g. Scott et al. 2001). Empirical research suggests that the present extinction rate is about one thousand times higher than a few thousand years ago (Novacek 2001, Hermy et al. 2007). Taking the effects of global change into account, this rate could even increase another tenfold (Anonymous 2005). This tremendous decline in species richness is largely the result of the severe human impact on the environment. With human populations, food demands and urbanization still increasing, the pressure on land remains intense and continues eroding the biodiversity of our planet. This clearly illustrates the need for nature conservation. A key strategy for protecting biodiversity has been the establishment and maintenance of protected areas (Gaston et al. 2008). Although the importance of protected areas for nature conservation is generally accepted, only few studies have actually tried to demonstrate their effectiveness (Parrish et al. 2003). Many of the limited studies that did, used a detour approach, which allowed them to test effectiveness without actually looking at the biodiversity as such. Most of these studies looked at protected area characteristics by using gap-analysis: overlaying species distribution maps with protected area maps (Jaffre et al. 1998, Yahnke et al. 1998, Hopkinson et al. 2000, Scott et al. 2001, Oldfield et al. 2004, Rodrigues et al. 2004, Chape et al. 2005, Gaston et al. 2006, Jackson & Gaston 2008). These studies assume that if a species’ distribution concurs with a protected area, this species is successfully protected. This kind of assessment likely leads to an overestimation of the degree of species protection, for example because of low resolution of map distribution and absence of any assessment of niche requirements (Rodrigues et al. 1999, Hopkinson et al. 2000). Another indirect approach quantifies the effects of different types of management, e.g. grazing and mowing on biodiversity. From these results is concluded that since these

Factors controlling germination and dormancy processes in dimorphic fruits of Atriplex inflata (Chenopodiaceae)

Abstract: In some species belonging to the Asteraceae, Chenopodiaceae, Poaceae and Brassicaceae, a single individual produces different morphophysiological types of seeds that differ in colour, size, shape, germination and dormancy (Imbert 2002, Li et al. 2005, Mandak & Pysek 2005). This phenomenon is known as seed dimorphism or seed polymorphism. This may be an adaptive feature to harsh environments (Mandak 1997). In halophytic species, including Arthrocnemum, Atriplex, Chenopodium, Salicornia, Salsola, Spergularia and Suaeda, seed polymorphism is considered as an adaption to saline environments (Li et al. 2005). It enables halophytes to respond to severe conditions and could provide multiple opportunities for germination and growth in saline ecosystems (Song et al. 2007). It is well known that in halophytes, seeds are exposed to severe salinity at the soil surface; this is not suitable for germination and seedling establishment. Upon salt dilution by rain, germination is maximal for non dormant seeds (Ungar 1995, Debez et al. 2004). However, in saline biotopes, salinity is in permanent fluctuation and the re-increase of soil salinity prevents germination (Easton & Kleindorfer 2008) and in some cases, it induces a secondary dormancy, like in seeds of Suaeda aralocaspica (Wang et al. 2008). It is well known that many seeds are dormant at maturity. Baskin & Baskin (2004) define five classes of dormancy in seeds of Angiosperms. They include physiological dormancy, morphological dormancy, morphophysiological dormancy, physical dormancy and combined dormancy (physical and physiological dormancy). Several methods are used to break dormancy including physical and chemical treatments. These treatments are specific for each type of dormancy (Mandak & Pysek 2001). For instance, the mechanical and acid scarifications are largely used for physically dormant seeds

Structural and floristic typology of the forests in the forest-savanna mosaic of the Lopé National Park, Gabon

Abstract: Background and aims - The Lope National Park in Gabon, recently added to the UNESCO world heritage list, presents a mosaic of forest and savanna that dynamically changes. Conserving this landscape requires an understanding of the forest dynamics. This study aims at defining a forest typology at Lope in relation with its dynamics. Methods - Floristic and structural characteristics for 265 tree species belonging to 55 families were measured in 258 sampling plots in the Lope National Park. Multivariate analysis of these data was used to partition the sampling plots into groups on the basis of their floristic or structural characteristics. Key results - Five structural forest types and six floristic forest types were identified. This typology showed that the forests in the forest-savanna mosaic of Lope organize themselves along a gradient of forest recovery, from young forests to mature forests. Typical pioneer species are associated with the youngest forest stages. The gradient on the species also corresponds to a geographical gradient on the sampling plots, associated with features like altitude, rocks, or hydrography. Conclusions - Five forest types were defined on the basis of species abundances. The snapshot of forest types characterizes a dynamic process of forest regeneration (Resume d'auteur)

Phytotoxic effects of a dominant weed Ligularia virgaurea on seed germination of Bromus inermis in an alpine meadow community.

Abstract: Background and aims - Ligularia virgaurea is an invasive weed species in the alpine meadow community that contains allelopathic compounds, which may affect seed germination of other co-existent species. Material and methods - In a laboratory study, allelopathic effects of root, stem and leaf aqueous extracts of Ligularia virgaurea, were evaluated on seed germination of Bromus inermis, a native grass species. Key results - Results showed that root, stem and leaf extracts of Ligularia virgaurea significantly decreased the germination percentage, relative germination percentage, germination index and weighted germination index of Bromus inermis. First germination time and mean germination time of Bromus inermis were also delayed. The concentration of the extracts had no significant effects on the germination indices. The type of extract (root, stem or leaf), on the contrary, showed the following trend on the mean relative germination percentage: RGP leaf extract treatment > RGP stem extract treatment > RGP root extract treatment. The response index values of root, stem and leaf aqueous extracts differ as follows: RI root extracts > RI stem extracts > RI leaf extracts. Conclusion - Our results demonstrate that aqueous extracts of Ligularia virgaurea have a significant allelopathic inhibition on seed germination of Bromus inermis. The root extracts of Ligularia virgaurea have a greater inhibition effect on seed germination of Bromus inermis, relative to stern and the leaf extracts.

The Cyperaceae in Madagascar show increased species richness in upland forest and wetland habitats

Abstract: Background and aims – Madagascar is a biodiversity hotspot with a high level of plant endemism. However, not all lineages of plants are equally represented and the highest diversity occurs in forest lineages. Cyperaceae frequently occur in grasslands and wetlands in Africa, and the tribe Hypolytreae and Carex subgenus Vigneastra are among the few predominantly forest lineages. We study the Cyperaceae of Madagascar to discover what lineages are represented (genera/tribes), to determine their unique habitats and key functional traits and to investigate patterns of species richness. Methods – The World Checklist of Monocotyledons was queried for Cyperaceae occurring in Madagascar. The global distribution of these species was investigated to identify endemic taxa and to evaluate other botanical countries where widespread species occur. Data on life form, habitat and photosynthetic type were scored from literature and personal observations. Key results – Madagascar has 321 species of Cyperaceae in 33 genera, representing all major clades of the family. The predominantly tropical Cypereae clade composes about half of the sedge flora, of which Cyperus represents about a third of the species in Madagascar. The Cariceae, a predominantly northern hemisphere temperate clade, is unusually highly represented and composes 10% of the sedge flora, occurring mostly in the highlands. In Madagascar, 55 species (17% of flora, mainly Carex and Cyperus) occur in forests and all are C3 perennials. Bulbostylis and Pycreus, exclusively C4 taxa with high proportion of annuals compared to C3 genera in Madagascar, occur outside forests in seasonal or permanent wetlands. Endemism among the sedge flora is 37% (121 species), a third of which (42 species) occur in forests, mostly in the Central and Eastern highlands. Conclusion – Cyperaceae are among top ten species richest angiosperm families in Madagascar. When compared with other botanical countries, Madagascar has the second highest endemism level, second to the Cape Provinces. The sedge flora assembly has involved long distance dispersal(s) coupled with Neogene radiation in upland humid forests and open wetland habitats.

Staelia culcita (Rubiaceae), a new species from Minas Gerais, Brazil

Abstract: Fil: Salas, Roberto Manuel. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Nordeste. Instituto de Botanica del Nordeste (i); Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; Argentina