Browsing by Autor "Michael Kessler"

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A NEW SPECIES OF TYRANNULET (TYRANNIDAE:<i>PHYLLOMYIAS</i>) FROM ANDEAN FOOTHILLS IN NORTHWEST BOLIVIA AND ADJACENT PERU
(Oxford University Press, 2008) Sebastián K. Herzog; Michael Kessler; José Antonio Balderrama
We describe Phyllomyias weedeni, a new species of tyrannulet (Tyrannidae) from the Bolivian and Peruvian Andes. The species is morphologically and vocally most similar to widely allopatric P. fasciatus (Planalto Tyrannulet), but vocalizations recorded at the six localities from which it is known differ conspicuously and significantly from those of P. fasciatus, and differences in plumage and measurements are also apparent. Vocalization analysis further suggests that the P. fasciatus complex, which comprises three named subspecies, may consist of more than one biological species. Phyllomyias weedeni inhabits the upper canopy of humid and semi-humid foothill and lower montane forest within a narrow elevational range (700–1,200 m). It appears to prefer irregularly structured canopy dominated by small-leaved trees but has also been found in a mosaic of shade-coffee (Coffea spp.) plantations and remnant forest patches. It occurs at low densities, is apparently patchily distributed, and has an estimated extent of occurrence of ≤10,000 km2. Its breeding population is estimated to be well below 10,000 mature individuals, and ongoing large-scale habitat conversion throughout much of the species' range could pose serious conservation problems. The new species thus qualifies as globally "vulnerable" under IUCN Red List Criteria. Further surveys are needed, especially in southeast Peru, to establish the extent of occurrence and population size of P. weedeni more precisely.
A synopsis of the Neotropical species of Sticherus (Gleicheniaceae), with descriptions of nine new species
(Q15088586, 2011) JASIVIA GONZALES R.; Michael Kessler
Sticherus (Gleicheniaceae) is a pantropical genus of about 95 species, characterized by scaly buds, mostly 1-forked veinlets in the segments, (2–)3–5(–7) sporangia per sorus, pseudodichotomously branched blades with pinnatifid or pinnate ultimate branches, and monolete spores. In the Neotropics, we recognize 54 species and three named hybrids. We provide typifications, distributional data, and a key for all species. Nine species are described as new: S. albus, S. antillensis, S. chocoensis, S. fuscus, S. jacha, S. moyobambensis, S. nervatus, S. ovatus, and S. rufus. The following new combinations are proposed: S. boliviensis, S. cubensis, S. decurrens, S. farinosus, S. ferrugineus, S. interjectus, S. lanosus, S. ×leonis, S. ×pseudobifidus, S. squamosus, and S. × subremotus.
Diversity patterns of vascular epiphytes along an elevational gradient in the Andes
(Wiley, 2005) Thorsten Krömer; Michael Kessler; S. Robbert Gradstein; Amparo Acebey
Abstract Aim To document the elevational pattern of epiphyte species richness at the local scale in the tropical Andes with a consistent methodology. Location The northern Bolivian Andes at 350–4000 m above sea level. Methods We surveyed epiphytic vascular plant assemblages in humid forests in (a) single trees located in (b) 90 subplots of 400 m 2 each located in (c) 14 plots of 1 ha each. The plots were separated by 100–800 m along the elevational gradient. Results We recorded about 800 epiphyte species in total, with up to 83 species found on a single tree. Species richness peaked at c. 1500 m and declined by c . 65% to 350 m and by c. 99% to 4000 m, while forests on mountain ridges had richness values lowered by c. 30% relative to slope forests at the same elevations. The hump‐shaped richness pattern differed from a null‐model of random species distribution within a bounded domain (the mid‐domain effect) as well as from the pattern of mean annual precipitation by a shift of the diversity peak to lower elevations and by a more pronounced decline of species richness at higher elevations. With the exception of Araceae, which declined almost monotonically, all epiphyte taxa showed hump‐shaped curves, albeit with slightly differing shapes. Orchids and pteridophytes were the most species‐rich epiphytic taxa, but their relative contributions shifted with elevation from a predominance of orchids at low elevations to purely fern‐dominated epiphyte assemblages at 4000 m. Within the pteridophytes, the polygrammoid clade was conspicuously overrepresented in dry or cold environments. Orchids, various small groups (Cyclanthaceae, Ericaceae, Melastomataceae, etc.), and Bromeliaceae (below 1000 m) were mostly restricted to the forest canopy, while Araceae and Pteridophyta were well represented in the forest understorey. Main conclusions Our study confirms the hump‐shaped elevational pattern of vascular epiphyte richness, but the causes of this are still poorly understood. We hypothesize that the decline of richness at high elevations is a result of low temperatures, but the mechanism involved is unknown. The taxon‐specific patterns suggest that some taxa have a phylogenetically determined propensity for survival under extreme conditions (low temperatures, low humidity, and low light levels in the forest interior). The three spatial sampling scales show some different patterns, highlighting the influence of the sampling methodology.
Ecology, biogeography and diversity of the Bolivian epiphytic cacti — with the description of two new taxa
(2000) Pierre L. Ibisch; Michael Kessler; Christoph Nowicki; Wilhelm Barthlott
We provide an overview of the taxonomy, ecology, and biogeography of the epiphytic cacti of Bolivia, which is second only to southeastern Brazil as a centre of epiphytic cactus diversity in South America. Twenty-one obligatory or facultative epiphytic species with 2 varieties in 7 genera occur in Bolivia. A further 14 species in 6 normally terrestrial genera are recorded as accidental epiphytes. Two taxa are described as new: Lepismium asuntapatense sp. nov. M. Kessler, P.L. Ibisch & Barthlott and Rhipsalis baccifera ssp. nov. cleistogama M. Kessler, P.L. Ibisch & Barthlott. Eight species are endemic to Bolivia, mostly in humid montane forests. Preliminary ecograms and extrapolated range maps for all obligatory epiphytes are provided. GIS-overlay of the range maps is used to predict the species diversity patterns for all obligatory epiphytes and for the genera of Rhipsalideae. Species-richness is highest in humid montane forests, but physiognomically and in relation to overall species-richness of vascular epiphytes, epiphytic cacti are most important in semi-humid montane forests of inter-Andean valleys and the Chaco zone. Three species are classified as vulnerable and all others as not endangered.
Inventario de grupos selectos de plantas en el Valle de Masicuri (Santa Cruz - Bolivia)
(2000) Michael Kessler; Thorsten Krömer; Iván Jiménez
INVENTORY OF SELECTED PLANT GROUPS IN THE MASICURI VALLEY (SANTA CRUZ - BOLIVIA) Se presenta una lista de Acanthaceae, Bromeliaceae, Cactaceae y Pteridophyta registrados entre 500 - 2450 m en el Valle de Masicuri localizado en el extremo norte de la region biogeografica Tucumano-Boliviana en el Departamento de Santa Cruz, Bolivia. Se registraron 22 especies de Acanthaceae, 32 de Bromeliaceae, 22 de Cactaceae y 187 de Pteridophyta y se estimaron el numero real de especies presentes en la zona en 28, 37, 23 Y 220, respectivamente. La diversidad de pteridofitos es menor que mas al norte en los Andes bolivianos, pero mayor que en el noroeste de la Argentina, documentando un decrecimiento gradual de la diversidad de norte a sur. La region contiene varias especies endemicas y otras 8' presumiblemente no descritas, asi como dos helechos previamente solo conocidos del Sur de Chile y Argentina, sugiriendo que puede haber fungido como una zona refugial. La riqueza de especies de pteridofitos tuvo su maximo a 1 900 -2 300 m, mientras que los otros grupos mostraron su mayor diversidad debajo de los 1000 m. Palabras clave: Acanthaceae, Bromeliaceae, Cactaceae, Pteridophyta, Region Tucumano-Boliviana, Bolivia. ABSTRACT We present a list of Acanthaceae, Bromeliaceae, Cactaceae, and Pteridophyta, recorded between 500 -2450 m in the Masicuri Valley, located at the northern end of the Tucumano-Bolivian biogeographic zone in the State of Santa Cruz, Bolivia. We found 22 species of Acanthaceae, 32 of Bromeliaceae, 22 of Cactaceae, and 187 of Pteridophyta and estima te actual species numbers to be 28, 37, 23, and 220, respectivelr The diversity of pteridophytes is lower than further north in the Bolivian Andes, but higher than in north-western Argentina, indicating a continuous north-south decline of species richness. The region contains a number of narrowly endemic and presumably undescribed species, as well as two ferns, otherwise only known from southern Chile and Argentina, suggesting that it mar have functioned as a refugial area. Species richness of ferns peaked in the most humid zone at 1 900 -2 300 m, while the other groups showed highest diversity below 1000 m. Key words: Acanthaceae, Bromeliaceae, Cactaceae, Pteridophyta, Tucumano-Bolivian region, Bolivia.
Non-woody life-form contribution to vascular plant species richness in a tropical American forest
(2008) Reynaldo Linares‐Palomino; Víctor Manuel Pardo Cardona; Ernest I. Hennig; Isabell Hensen; Doreen Hoffmann; Jasmin Lendzion; Daniel P. Soto; Sebastián K. Herzog; Michael Kessler
We provide total vascular plant species counts for three 1-ha plots in deciduous, semi-deciduous and evergreen forests in central Bolivia. Species richness ranged from 297 species and 22,360 individuals/ha in the dry deciduous forest to 382 species and 31,670 individuals/ha in the evergreen forest. Orchidaceae, Pteridophyta and Leguminosae were among the most species-rich major plant groups in each plot, and Peperomia (Piperaceae), Pleurothallis (Orchidaceae) and Tillandsia (Bromeliaceae), all epiphytes, were the most species-rich genera. This dominance of a few but very diverse and/or widespread taxa contrasted with the low compositional similarity between plots. In a neotropical context, these Central Bolivian forest plots are similar in total species richness to other dry deciduous and humid montane forests, but less rich than most Amazonian forests. Nevertheless, lianas, terrestrial herbs and especially epiphytes proved to be of equal or higher species richness than most other neotropical forest inventories from which data are available. We therefore highlight the importance of non-woody life-forms (especially epiphytes and terrestrial herbs) in Andean foothill forest ecosystems in terms of species richness and numbers of individuals, representing in some cases nearly 50% of the species and more than 75% of the individuals. These figures stress the need for an increased inventory effort on non-woody plant groups in order to accurately direct conservation actions.
Non-woody life-form contribution to vascular plant species richness in a tropical American forest
(Springer Science+Business Media, 2008) Reynaldo Linares‐Palomino; Víctor Manuel Pardo Cardona; Ernest I. Hennig; Isabell Hensen; Doreen Hoffmann; Jasmin Lendzion; Daniel P. Soto; Sebastián K. Herzog; Michael Kessler
We provide total vascular plant species counts for three 1-ha plots in deciduous, semi-deciduous and evergreen forests in central Bolivia. Species richness ranged from 297 species and 22,360 individuals/ha in the dry deciduous forest to 382 species and 31,670 individuals/ha in the evergreen forest. Orchidaceae, Pteridophyta and Leguminosae were among the most species-rich major plant groups in each plot, and Peperomia (Piperaceae), Pleurothallis (Orchidaceae) and Tillandsia (Bromeliaceae), all epiphytes, were the most species-rich genera. This dominance of a few but very diverse and/or widespread taxa contrasted with the low compositional similarity between plots. In a neotropical context, these Central Bolivian forest plots are similar in total species richness to other dry deciduous and humid montane forests, but less rich than most Amazonian forests. Nevertheless, lianas, terrestrial herbs and especially epiphytes proved to be of equal or higher species richness than most other neotropical forest inventories from which data are available. We therefore highlight the importance of non-woody life-forms (especially epiphytes and terrestrial herbs) in Andean foothill forest ecosystems in terms of species richness and numbers of individuals, representing in some cases nearly 50% of the species and more than 75% of the individuals. These figures stress the need for an increased inventory effort on non-woody plant groups in order to accurately direct conservation actions.
Pleistocene climatic oscillations rather than recent human disturbance influence genetic diversity in one of the world's highest treeline species
(Wiley, 2015) Yanling Peng; Susanne Lachmuth; Silvia C. Gallegos; Michael Kessler; Paul M. Ramsay; Daniel Renison; Ricardo Suarez; Isabell Hensen
Our study shows that, unlike the case for other Andean treeline species, recent human activities have not affected the genetic structure of P. tarapacana, possibly because its inhospitable habitat is unsuitable for agriculture. The current genetic pattern of P. tarapacana points to a historically more widespread distribution at lower altitudes, which allowed considerable gene flow possibly during the glacial periods of the Pleistocene epoch, and also suggests that the northern Argentinean Andes may have served as a refugium for historical populations.
Pollen analogues are transported across greater distances in bee‐pollinated than in hummingbird‐pollinated species of <i>Justicia</i> (Acanthaceae)
(Wiley, 2019) Alexander N. Schmidt‐Lebuhn; Mathias Müller; Paola Pozo; Francisco Encinas‐Viso; Michael Kessler
Abstract Several hummingbird‐pollinated plant lineages have been demonstrated to show increased rates of diversification compared to related insect‐pollinated lineages. It has been argued that this pattern is produced by a higher degree of specialization on part of both hummingbirds and plants. We here test an alternative hypothesis: The often highly territorial hummingbirds may on average carry pollen over shorter distances than other pollinators and drive diversification by reducing gene flow distances. We present experimental data from pollen analogue tracking showing shorter dispersal distances in hummingbird‐pollinated than in bee‐pollinated species among ten Neotropical species of Justicia (Acanthaceae). Abstract in Spanish is available with online material.
Prodromus of a fern flora for Bolivia. XL. Polypodiaceae
(Q15088586, 2018) Alan Р. Smith; Michael Kessler; Blanca León; Thaís Elias Almeida; Iván Jiménez Pérez; Marcus Lehnert
We provide a synopsis to the family Polypodiaceae in Bolivia, comprising 23 genera and 209 species, which renders this the most species-rich fern family in the country. Two large subfamilies are recognized, Polypodioideae, with 113 species in eight genera, and Grammitidoideae, with 95 species in 14 genera; a third subfamily, Platycerioideae, mostly paleotropical, is represented by one native species in the genus Platycerium. Two new combinations are made: Microgramma nana (Liebm.) T.E.Almeida and Pleopeltis burchellii (Baker) Hickey & Sprunt ex A.R.Sm.
The Influence of Climatic Seasonality on the Diversity of Different Tropical Pollinator Groups
(Public Library of Science, 2011) Stefan Abrahamczyk; Jürgen Kluge; Yuvinka Gareca; Steffen Reichle; Michael Kessler
Tropical South America is rich in different groups of pollinators, but the biotic and abiotic factors determining the geographical distribution of their species richness are poorly understood. We analyzed the species richness of three groups of pollinators (bees and wasps, butterflies, hummingbirds) in six tropical forests in the Bolivian lowlands along a gradient of climatic seasonality and precipitation ranging from 410 mm to 6250 mm. At each site, we sampled the three pollinator groups and their food plants twice for 16 days in both the dry and rainy seasons. The richness of the pollinator groups was related to climatic factors by linear regressions. Differences in species numbers between pollinator groups were analyzed by Wilcoxon tests for matched pairs and the proportion in species numbers between pollinator groups by correlation analyses. Species richness of hummingbirds was most closely correlated to the continuous availability of food, that of bees and wasps to the number of food plant species and flowers, and that of butterflies to air temperature. Only the species number of butterflies differed significantly between seasons. We were not able to find shifts in the proportion of species numbers of the different groups of pollinators along the study gradient. Thus, we conclude that the diversity of pollinator guilds is determined by group-specific factors and that the constant proportions in species numbers of the different pollinator groups constitute a general pattern.