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Zürich, Switzerland

Lewis G.P.,Herbarium | Hughes C.E.,University of Oxford | Hughes C.E.,Institute for Systematic Botany | Yomona A.D.,Agrarian National University | And 3 more authors.
Kew Bulletin

Two new species of legume, Caesalpinia celendiniana and Mimosa lamolina and one new variety, Caesalpinia pluviosa var. maraniona, from the inter-Andean Río Marañón Valley in northern Perú are described and illustrated. These add to the already impressive tally of endemics known from the seasonally dry tropical forests of the Río Marañón Valley, which apparently far exceeds the endemic plant diversity from other nearby inter-Andean dry valleys in Perú and southern Ecuador. © 2010 The Board of Trustees of the Royal Botanic Gardens, Kew. Source

Steinmann K.,Swiss Federal Institute of forest | Eggenberg S.,Atelier fur Naturschutz und Umweltfragen UNA AG | Wohlgemuth T.,Swiss Federal Institute of forest | Linder H.P.,Institute for Systematic Botany | Zimmermann N.E.,Swiss Federal Institute of forest
Ecological Complexity

The species-area curve is generated by niche-related factors and stochastic factors like neutral processes or dispersal. Even though the use of environmental variables is widespread to predict the spatial distribution of species richness, it remains difficult to distinguish the relative importance of habitat heterogeneity and the area effect on total species richness. In our study, we used different types of species-area curves to disentangle the habitat heterogeneity effect and the area effect on vascular plant species richness. We generated three types of sample rarefaction curves: (1) a randomly aggregated rarefaction curve, (2) a rarefaction curve for which areas of similar habitat types were aggregated and (3) a rarefaction curve, for which areas of dissimilar habitat types were aggregated. These analyses were made on three data sets separately with different grain sizes to investigate if this had an effect on the observed pattern. The classification of the habitat types was based on three environmental variables (mean annual temperature, mean moisture index and the slope of the terrain). A consistent pattern of sample rarefaction curves was found with all three data sets. While the aggregation of dissimilar habitat types showed the highest species accumulation rates and saturation levels, the lowest accumulation rates and saturation levels were found when similar habitat types were aggregated. Depending on the grain size, the habitat heterogeneity effect accounted for 20-30% to the total species richness. However, this effect was not statistically significant. The results indicate, that effects of niche related factors on the species-area curve are scale dependent and that effects related to the area are at least as important in explaining the species richness. © 2011 Elsevier B.V. Source

Wunderlin R.P.,Institute for Systematic Botany | Hansen B.F.,Institute for Systematic Botany | Franck A.R.,Institute for Systematic Botany | Bradley K.A.,Institute for Regional Conservation | Kunzer J.M.,Tomoka State Park
Journal of the Botanical Research Institute of Texas

Thirty four taxa are reported as new to Florida, of which 26 are here reported for the first time as occurring in thecontinental United States Of the total, 33 are non-native to Florida. Of these 33, 25 are ornamentals escaped from cultivation, several of which have the potential to become invasive. Source

Abrahamczyk S.,Institute for Systematic Botany | Kessler M.,Institute for Systematic Botany
Journal of Ornithology

As for many other taxa, hummingbird diversity declines away from the equator, but the causes for this decline are still disputed and might involve, among others, climatic factors or the availability of food resources. Because hummingbirds are one of the classical examples for plant-animal coevolution, it has been proposed that the diversity of hummingbird assemblages might depend on the diversity of food plants available. We tested this hypothesis by studying the hummingbird assemblages and their food plants for 1 year at six sites along a 660-km-long transect in Bolivian lowland forests extending from the southernmost Amazonian rain forests to dry Chaco forests. Hummingbird diversity was higher in the northern three sites as compared to the southern ones, with an abrupt decline in species numbers and a corresponding change in taxonomic composition at the boundary from evergreen to drought deciduous forests. Hummingbird diversity and abundance were only weakly correlated to climatic factors or to the diversity of humming-visited flowers, but strongly to the seasonal abundance of flowers. The overlap in nectar diet between hummingbird species depended on the number of plant species: when numerous species were available, the hummingbirds segregated by feeding preferences, but when few flowers were available, all hummingbirds fed on the same plants. We conclude that the local diversity of hummingbird species is not primarily determined by the diversity of food plants, but rather by the abundance of flowers available at any given point in time. © 2010 Dt. Ornithologen-Gesellschaft e.V. Source

Abrahamczyk S.,Institute for Systematic Botany | Kessler M.,Institute for Systematic Botany
Bulletin of the British Ornithologists' Club

Little is known about the distribution, ecology and behaviour of hummingbirds in the Andean foothills of Bolivia, where many lowland hummingbird species reach their south-western distributional limits. In November 2007-October 2008, we surveyed hummingbirds at six sites along a 660-km transect, from tropical Amazonian humid forest to subtropical spiny forest of the Gran Chaco. In total, we found 21 hummingbird species. For ten of these, we provide new information on latitudinal and elevational movements, feeding or breeding behaviour. In particular, we provide evidence for seasonal movements of five species, including such widespread taxa as White-chinned Sapphire Hylocharis cyanus and Fork-tailed Woodnymph Thalurania furcata, which are considered sedentary throughout most of their ranges, but which appear to undergo seasonal movements at their range limits in Bolivia. © British Ornithologists' Club 2010. Source

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