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Madrid, Spain

Fernandez-Zamudio R.,University of Seville | Garcia-Murillo P.,University of Seville | Cirujano S.,Royal Botanical Garden
Aquatic Botany

Spore germination characteristics of Azolla filiculoides Lamarck, a recent invader of the Doñana Mediterranean wetlands, have been quantified experimentally. Batches of spores were subjected to different storage conditions, salinity concentrations, phosphorus availability and drought effects. Cold pre-treatment did not stimulate spore germination, whereas drought, a characteristic different from Azolla's native habitat, reduced it (40±7 vs 13±5). Germination declined with the increase of salinity (r=-0.50, notably above 5000μScm-1), whereas phosphorus availability had no significant effect. © 2010 Elsevier B.V. Source

Alvarez-Cobelas M.,National Museum of Natural History | Angeler D.G.,Swedish University of Agricultural Sciences | Rojo C.,University of Valencia | Cirujano S.,Royal Botanical Garden
Anales del Jardin Botanico de Madrid

Phytoplankton production (PP) in wetlands is not measured as often as that of macrophytes. A three year-study during a period of sustained high flooding was undertaken in a central Spanish floodplain wetland (Las Tablas de Daimiel National Park) to determine net PP, its spatial heterogeneity and controlling factors, and compare it with primary production in macrophyte communities. This enabled us to estimate carbon budgets for each community. All PP variables showed high spatial and temporal variability among sites, resulting in low coherence even when flooding connected all sites. Net PP corresponded to 25-36% of submerged plant production and 3-10% of helophyte production. Net PP was controlled by different size fractions of phytoplankton biomass at different wetland sites. Neither nutrients nor zooplankton affected net PP or productivity. A high spatiotemporal variability of PP in wetlands occurs arising from complex processes that affect the underwater light field. Carbon budgets of phytoplankton often exceeded those of submerged macrophytes and attained between 4 and 37% of helophyte budgets. Although usually considered to be marginal, our study shows that PP in the open water of wetlands should be taken into account for determining accurate wetland carbon budgets, mostly in periods of high flooding, which often result in changing the carbon budget of primary producers. Source

Mikic A.,Serbian Institute of Field and Vegetable Crops | Smykal P.,Palacky University | Kenicer G.,Royal Botanical Garden | Vishnyakova M.,Russian Academy of Agricultural Sciences | And 18 more authors.
Botanical Journal of the Linnean Society

Vavilovia formosa is a relict, endangered species from the highlands of the Caucasus and the Near East. Described in 1812, it has had an uncertain status and was finally recognized as a separate genus of tribe Fabeae (Fabaceae). Our informal international group was established in 2007 to revive the interest in this species as it had been seriously neglected for decades. Here, we provide an overview of the accumulated knowledge on V.formosa and present the results of the most recent multidisciplinary research. Three expeditions were made to two locations in Armenia in 2009, providing the material for anatomical, morphological, chemical and molecular analysis. Unlike previous attempts, ex situ conservation in Yerevan and in vitro propagation, important for potential interspecific hybridization, were successful. Molecular tools were used to clarify the taxonomic position of V.formosa, often considered the closest to the extinct ancestor of the whole tribe. The analysis of four informative regions of plastid and nuclear DNA showed that V.formosa belongs to the same clade as Lathyrus and Pisum, with a distinct status. Preservation and maintenance of V.formosa remains the only basis for further development of all other scientific aspects, especially breeding and uses in agronomy. © 2013 The Linnean Society of London. Source

Rejou-Mechain M.,CNRS Biological Evolution and Diversity Laboratory | Muller-Landau H.C.,Smithsonian Tropical Research Institute | Detto M.,Smithsonian Tropical Research Institute | Thomas S.C.,University of Toronto | And 66 more authors.

Advances in forest carbon mapping have the potential to greatly reduce uncertainties in the global carbon budget and to facilitate effective emissions mitigation strategies such as REDD+ (Reducing Emissions from Deforestation and Forest Degradation). Though broad-scale mapping is based primarily on remote sensing data, the accuracy of resulting forest carbon stock estimates depends critically on the quality of field measurements and calibration procedures. The mismatch in spatial scales between field inventory plots and larger pixels of current and planned remote sensing products for forest biomass mapping is of particular concern, as it has the potential to introduce errors, especially if forest biomass shows strong local spatial variation. Here, we used 30 large (8-50 ha) globally distributed permanent forest plots to quantify the spatial variability in aboveground biomass density (AGBD in Mg ha-1) at spatial scales ranging from 5 to 250 m (0.025-6.25 ha), and to evaluate the implications of this variability for calibrating remote sensing products using simulated remote sensing footprints. We found that local spatial variability in AGBD is large for standard plot sizes, averaging 46.3% for replicate 0.1 ha subplots within a single large plot, and 16.6% for 1 ha subplots. AGBD showed weak spatial autocorrelation at distances of 20-400 m, with autocorrelation higher in sites with higher topographic variability and statistically significant in half of the sites. We further show that when field calibration plots are smaller than the remote sensing pixels, the high local spatial variability in AGBD leads to a substantial "dilution" bias in calibration parameters, a bias that cannot be removed with standard statistical methods. Our results suggest that topography should be explicitly accounted for in future sampling strategies and that much care must be taken in designing calibration schemes if remote sensing of forest carbon is to achieve its promise. © Author(s) 2014. Source

Russell A.,University of Vienna | Samuel R.,University of Vienna | Bogarin D.,University of Costa Rica | Fernando S.,Royal Botanical Garden | And 3 more authors.
Botanical Journal of the Linnean Society

Amplified fragment length polymorphism (AFLP) markers were used to investigate the relationships among Polystachya accessions from a group of closely related pantropical tetraploids. Before starting with the fingerprinting analyses, the polyploid accessions were first included in a phylogenetic analysis using low-copy nuclear DNA data to establish their relationships, which confirmed that they belonged to a species group of closely related allotetraploids. Neo- and Palaeotropical polyploid accessions formed two hybrid clades with apparently independent origins. Sampling for the AFLP analyses included single accessions from much of the range of the genus and populations from Costa Rica (CR) and Sri Lanka (SL) to compare population structure and genetic diversity in these two areas in more detail. A splits graph of the complete AFLP data showed three major clusters corresponding to three sources of population sampling (P.concreta, SL; P.foliosa, CR; P.masayensis, CR), with individual accessions from Africa and Indian Ocean islands showing a closer relationship to P.concreta from SL than to the two CR species. Individual accessions from the Neotropics occurred in more isolated positions in the splits network, with little resolution. Some P.foliosa accessions clustered with P.masayensis, suggesting some hybridization between the two species, and this was confirmed by Bayesian structure analysis. However, the splits network, structure and analyses of molecular variance indicated a generally high level of genetic divergence between the two CR species, despite their recent hybrid origin, occurrence in largely the same localities and occasional hybridization. Polystachya foliosa from CR had a higher degree of population-level genetic structure (ΦST=0.291) than P.masayensis from CR (ΦST=0.161) and P.concreta from SL (ΦST=0.138), possibly because of its occurrence within a larger and more environmentally diverse continuous range than the other two species. Genetic divergence between Neo- and Palaeotropical members of the pantropical tetraploid group of Polystachya and the nonmonophyly of P.concreta suggested that P.concreta s.l. should be split and the use of this epithet should be confined to the Neotropics (the type is from Martinique). Other names should be used in Africa and the Asian tropics. © 2010 The Linnean Society of London. Source

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