20 results on '"Aas, Gregor"'
Search Results
2. Plasticity of plant silicon and nitrogen concentrations in response to water regimes varies across temperate grassland species
- Author
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Klotz, Marius, Schaller, Jörg, Feldhaar, Heike, Dengler, Jürgen, Gebauer, Gerhard, Aas, Gregor, Weissflog, Anita, Engelbrecht, Bettina M. J., Klotz, Marius, Schaller, Jörg, Feldhaar, Heike, Dengler, Jürgen, Gebauer, Gerhard, Aas, Gregor, Weissflog, Anita, and Engelbrecht, Bettina M. J.
- Abstract
1. Temperate grasslands exhibit strong spatial and temporal variation in water regimes. Thus, grassland plants experience potentially stressful water regimes, which may influence their tissue silicon (Si) and nitrogen (N) concentrations. Plant Si and N concentrations play important ecological roles in temperate grasslands, for example, by influencing plant performance and herbivory, yet comparisons of species' responses to a broad range of water regimes, including drought, waterlogging and flooding, are lacking. 2. We conducted a mesocosm experiment with 10 temperate grassland species of two life-forms (grasses and forbs) exposed to four different soil water regimes (drought, a benign control, waterlogged and flooded conditions), and analysed their Si and N concentrations. 3. Grasses showed lower Si concentrations under drought and flooding compared to the benign control and the highest concentrations emerged under waterlogging. Overall, plant Si responses of grasses were more uniform, while in forbs, responses varied both in direction and magnitude across species. For N concentrations, all species and life-forms showed the highest concentrations under drought compared to the benign control, while half of the species exhibited decreasing concentrations under waterlogging and/or flooding. The water regimes, especially waterlogging and flooding, induced changes in species rankings of plant Si and N concentrations, with stronger shifts in forbs than in grasses. 4. Our results indicate that spatial and temporal variation of water regimes may influence plant Si and N concentrations in temperate grassland species. Plant Si responses to water regimes might be highly species-specific in forbs but more similar in grasses, whereas plant N responses are likely to be relatively uniform across species and life-forms. 5. The strong plasticity in plant Si and N concentrations we observed might have pervasive consequences for ecological processes, such as herbivory.
- Published
- 2023
3. Distribution ranges and spring phenology explain late frost sensitivity in 170 woody plants from the Northern Hemisphere
- Author
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Muffler, Lena, Beierkuhnlein, Carl, Aas, Gregor, Jentsch, Anke, Schweiger, Andreas H., Zohner, Constantin, and Kreyling, Juergen
- Published
- 2016
4. Plasticity of plant silicon and nitrogen concentrations in response to water regimes varies across temperate grassland species
- Author
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Klotz, Marius, primary, Schaller, Jörg, additional, Feldhaar, Heike, additional, Dengler, Jürgen, additional, Gebauer, Gerhard, additional, Aas, Gregor, additional, Weissflog, Anita, additional, and Engelbrecht, Bettina M. J., additional
- Published
- 2022
- Full Text
- View/download PDF
5. Genetic structure of three Sorbus latifolia (Lam.) Pers. taxa endemic to northern Bavaria
- Author
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Feulner, Martin, Liede-Schumann, Sigrid, Meve, Ulrich, Weig, Alfons, and Aas, Gregor
- Published
- 2013
- Full Text
- View/download PDF
6. Genotypical and multiple phenotypical traits discriminate Salix × rubens Schrank clearly from its parent species
- Author
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Kehl, Alexandra, Aas, Gregor, and Rambold, Gerhard
- Published
- 2008
7. Effects of skid trails on understory vegetation in forests : a case study from Northern Bavaria (Germany)
- Author
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Mercier, Paula, Aas, Gregor, Dengler, Jürgen, Mercier, Paula, Aas, Gregor, and Dengler, Jürgen
- Abstract
While it is well-known that skid trails in forests locally increase soil compaction and illumination, the effect on vegetation and its spatial and temporal variation have hardly been studied in temperate forests. We surveyed Norway Spruce (Picea abies), Scots Pine (Pinus sylvestris) and European Beech (Fagus sylvatica) dominated forests to reflect the range of the prevalent forests types and ecological gradients of Northern Bavaria, Germany. In each forest type, we chose skid trails with different times since last use (0−2 years ago, 3−6 years ago, ≥ 7 years ago) to address the temporal aspect and sampled 4-m² plots on the trail itself, adjacent to the trail and in the forest interior to address the spatial aspect. We analysed the response of soil compaction, canopy cover, vascular plant and bryophyte species richness, vegetation cover and height, both in total and differentiated by layer, and mean ecological indicator values to the use of skid trails. Skid trails exhibited significantly higher soil compaction together with a more diverse, more light and moisture demanding vegetation compared to the forest interior. On the trails, graminoids were favoured over woody perennials. Vegetation adjacent to the skid trail resembled the forest interior, yet soil compaction exceeded that of the forest interior. Irrespective of time since last use, the soils on skid trails remained more compacted and likewise ecological response of understory vegetation did not change with time. Canopy cover and species richness responded strongly site-specific, and effects lasted the longest in the surveyed Scots Pine dominated forests but were diminished in European Beech dominated forests. Our results indicate a shift to a more ruderal and wetland-like vegetation on skid trails, which, however, hardly extended into the adjacent forest stand. Overall, plot-scale richness was higher on skid trails than in adjacent the adjacent forest, suggesting that skid trails could contribute to greater h
- Published
- 2019
8. Genetic variability and morphology of tri- and tetraploid members of the Sorbus aria complex in northern Bavaria
- Author
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Feulner, Martin, primary, Weig, Alfons, additional, Paule, Juraj, additional, Gregor, Thomas, additional, Schott, Lea F., additional, and Aas, Gregor, additional
- Published
- 2017
- Full Text
- View/download PDF
9. Marri, Mallee, Mulga: Pflanzenvielfalt Westaustraliens
- Author
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Lauerer, Marianne, Nicolle, Dean, French, Malcolm, Börner, Annett, Aas, Gregor, and Schulze, Ernst-Detlef
- Abstract
Westaustralien ist einer der „Hot Spots“ der Biodiversität der Erde. Es beherbergt über 10 000 Pflanzenarten, darunter viele endemische. Von besonderer Bedeutung für diese Region sind Eukalypten, zu denen neben der bekannten Gattung Eucalyptus auch Corymbia gehört, die erst in jüngerer Zeit als eigene Gattung von Eucalyptus abgetrennt wurde. Dargestellt werden verschiedene von Eukalypten dominierte Vegetationstypen Westaustraliens, ferner die küstennahen Banksia-Heidegebüsche im Südwesten, Acacia-Buschländer und die halbimmergrünen Trockenwälder und Savannen der Kimberleys., Der Palmengarten, Bd. 75 Nr. 1 (2011)
- Published
- 2011
- Full Text
- View/download PDF
10. Verbreitung, Häufigkeit und Verjüngung von Sorbus cordigastensis (Kordigast-Mehlbeere) in der nördlichen Frankenalb
- Author
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Aas, Gregor and Kohles, Matthias
- Subjects
ddc:580 - Abstract
Sorbus cordigastensis N. Mey. (Kordigast-Mehlbeere) ist eine Rote-Liste-Art aus dem Komplex hybridogener Sippen von Sorbus aria und S. torminalis, die endemisch am Kordigast, einem Zeugenberg des Oberen Jura in der Weismainalb (Naturraum „Nördliche Fränkische Alb“) vorkommt. Ziel der Untersuchung war es, die Verbreitung und Größe der Population sowie den Zustand ihrer Verjüngung zu erfassen. Zu diesem Zweck wurden sämtliche im Gebiet vorkommenden Individuen mit einer Wuchshöhe über 1,3 m punktgenau kartiert. In drei etwa 0,35–0,4 ha großen Waldbeständen wurden mittels Stichprobenverfahren die Anzahl und Wuchshöhe der Jungpflanzen sowie das Ausmaß der Wildschäden ermittelt. Sorbus cordigastensis ist mit etwa einem größeren (> 1,3 m hoch) Individuum pro Hektar im untersuchten Gebiet selten, kommt aber lokal und insbesondere an Waldrändern gehäuft vor. In Beständen mit fruktifizierenden Altbäumen verjüngt sich die Art gut. In den drei untersuchten Waldbeständen konnten, bezogen auf einen Hektar Fläche, im Durchschnitt etwa 1500 Jungpflanzen mit einer Wuchshöhe < 1,3 m nachgewiesen werden. Der Großteil davon ist weniger als 30 cm hoch, Jungpflanzen über 90 cm Höhe fehlen jedoch. Eine der Ursachen dafür sind starke Wildschäden. Bei zwei Drittel aller Jungpflanzen ist der Leittrieb ein- oder mehrmals verbissen. Verschiedene Beobachtungen weisen darauf hin, dass darüber hinaus Lichtmangel in den relativ dichten Beständen die dauerhafte Etablierung der Verjüngung beeinträchtigt. Die Population der Kordigast-Mehlbeere ist derzeit an ihrem Naturstandort noch relativ groß und gut zur Reproduktion fähig. Da sich ihre Verjüngung aber nicht ausreichend etablieren kann, ist der Bestand auf längere Sicht vom Aussterben bedroht. Schutzmaßnahmen müssen darauf abzielen, die Bedingungen für das Aufwachsen der Verjüngung durch Verringerung der Wildschäden und Auflichtung der Bestände zu verbessern. Sorbus cordigastensis N. Mey. is an endangered apomictic taxon of hybrid origin between Sorbus aria und S. torminalis. It is endemically distributed at the Kordigast, an outlier table mountain of upper Jurassic limestone sediments (Malm) situated at the northern edge of the Weismainalb Mountains (Northern Franconian Alb, Bavaria, Germany). In order to examine the size and distribution of its population as well as its capacity for natural regeneration, all individuals with a height of more than 1.3 m were mapped with a Global Positioning System. In addition, the number, tree height, and browsing damages of juvenile plants found in three selected forest stand plots of 0.35–0.4 ha size were analysed in random subsamples. Large trees (> 1.3 m) of Sorbus cordigastensis are rare in the study area and occur with a density of approximately one individual per hectare. However, they tend to form local clusters near forest edges. In forest stands with fruit-bearing trees an average of 1500 juvenile plants (height < 1.3 m) per hectare was encountered. Most saplings are less than 30 cm high. Individuals with more than 90 cm height are completely lacking, mainly as a result of severe browsing which damages the leading shoot of two thirds of all plants. There are also indications that lack of light in the dense forest stands prevents a long-lasting establishment of the rejuvenation. At present the population of Sorbus cordigastensis appears to be of adequate size and capable of reproducing successfully in its natural habitat. However, the species is threatened by extinction in the near future because the opportunities for its rejuvenation are insufficient for the plants to reach an adult stage. Efforts for conservation of the species should strive to protect it from browsing damage and to enhance light conditions for seedling growth by moderate thinning of existing forest stands.
- Published
- 2010
11. Wald mit zwei Gesichtern: Pazifischer Trockenwald in Nordwest-Peru
- Author
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Lauerer, Marianne, Horna, Viviana, Zimmermann, Reiner, Vásquez, Pedro, and Aas, Gregor
- Abstract
Im Nordwesten Perus, nahe der ekuadorianischen Grenze, liegt das Biosphärenreservat „La Reserva de Biosféra del Noroeste“. Es umfasst vor allem Trockenwälder der arten- und endemitenreichen Florenregion Amotape-Huancabamba und gliedert sich in vier Schutzgebiete. Eines dieser Gebiete (Coto de Caza El Angolo) wird seit mehreren Jahren für ökophysiologische Untersuchungen von den Autoren aufgesucht. Die klimatischen Verhältnisse und die Vegetation dieser Region sowie charakteristische Pflanzenarten und deren Ökologie werden vorgestellt. Die tropische, regengrüne Vegetation dieses pazifischen Trockenwaldes dient als Vorbild für ein Trockenwaldhaus im Ökologisch-Botanischen Garten der Universität Bayreuth, mit dessen Gestaltung im Sommer 2007 begonnen wurde., Der Palmengarten, Bd. 72 Nr. 1 (2008)
- Published
- 2008
12. Relevance of phenology of seed dispersal and water level on the establishment of seedlings of different Salix-species on restored river sites
- Author
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Kehl, Alexandra, Reuter, Andreas, and Aas, Gregor
- Subjects
ddc:580 - Abstract
Weiden (Salix spp., Salicaceae) gehören zu den typischen Gehölzarten der Flussauen in Mitteleuropa. Viele Arten dieser Gattung haben ähnliche Eigenschaften (life history traits) und Strategien bei der Besiedelung frisch entstandener Rohböden. In Auenhabitaten kommen deshalb häufig mehrere Weidenarten gemeinsam vor und treten deshalb miteinander in Konkurrenz. In der vorliegenden Arbeit wurde untersucht, ob interspezifische phänologische Unterschiede in der Zeit der Samenausbreitung in Verbindung mit wechselnden Pegelständen des Flusses dazu führen, dass sich koexistierende Weidenarten räumlich differenziert ansiedeln und so die interspezifische Konkurrenz zwischen den Weiden reduziert wird. Auf frisch sedimentierten Auenböden an der Rodach und am Oberlauf des Mains (Oberfranken, Nordostbayern) wurde der Einfluss der Zeit des Samenfluges und der Schwankung der Pegelstände auf die räumliche Verteilung der Keimlinge von Salix fragilis s.l., S. purpurea, S. triandra und S. viminalis auf zwei Aufnahmeflächen untersucht. Ergänzt wurden diese Freilandstudien durch Untersuchungen zur Keimfähigkeit von Samen dieser Arten unter verschiedenen Bedingungen im Labor. Die Keimfähigkeit der Samen betrug unmittelbar nach ihrer Reife mindestens 80-100%. Bei trockener Lagerung (20 °C) erlosch die Keimfähigkeit von S. fragilis und S. triandra nach 4 Wochen, bei S. purpurea und S. viminalis nach spätestens 6 Wochen. Die Samen aller Arten können auch im Wasser keimen. Anhand des Zeitraumes der Samenausbreitung lassen sich die im Freiland untersuchten Weiden in eine früh (S. purpurea und S. viminalis) und in eine spät fruktifizierende Gruppe (S. fragilis s.l. und S. triandra) unterscheiden. Die Keimlinge aller Arten traten jeweils nur in einem schmalen Saum entlang des Ufers auf. Die Pegel von Main und Rodach an den Untersuchungsflächen waren während des Samenfluges der früh fruktifizierenden Gruppe höher als während des Samenfluges der spät fruktifizierenden Gruppe. Keimlinge beider Gruppen etablierten sich deshalb in unterschiedlichen Reliefbereichen und in unterschiedlicher Entfernung zum Ufer: bezogen auf einen sommerlichen Tiefstand des Wassers waren die Keimlinge der früh fruktifizierenden Arten (S. purpurea und S. viminalis) höher auf der Kiesbank und weiter vom Ufer entfernt als die der spät fruktifizierenden Arten (S. fragilis s.l. und S. triandra). Phänologische Unterschiede ermöglichen somit in Kombination mit sinkenden Wasserständen eine räumlich differenzierte Verteilung von Keimlingen verschiedener Weidenarten auf engstem Raum. Dies trägt zur Verringerung interspezifischer Konkurrenz und zu einer hohen Diversität von Salix-Arten in alluvialen Habitaten bei. Willows (Salix spp.) belong to the typical woody vegetation in alluvial habitats in Central Europe. Many species exhibit similar life history traits and strategies to colonize bare soil. Therefore, several willow species occur in alluvial habitats, and interspecific competition may become important. In this study, we investigated the relevance of the interspecific variation of seed distribution phenology in combination with water level fluctuations for a spatial differentiation of the coexisting species which may lead to a reduction of interspecific competition. We investigated the spatial distribution of willow seedlings of the species Salix fragilis s.l., S. purpurea, S. triandra and S. viminalis and its dependence of seed dispersal time and fluctuations of water level in the years 2000 and 2001 on two sample plots at the rivers Rodach and Main (Germany, Bavaria, Upper Franconia). Additional investigations on germination characteristics of different species revealed that germination rates were at least 80% immediately after seed ripening, but seed viability decreased very rapidly under warm, dry storage conditions. Salix fragilis s.l. and S. triandra lost their germination ability completely after 4 weeks, S. purpurea and S. viminalis after 6 weeks. Germination was also possible while seeds were floating in water. According to seed dispersal time, the species can be divided into early dispersers (S. viminalis, S. purpurea)and late dispersers (S. fragilis s.l., S. triandra). All seedlings occurred only in a narrow zone parallel to and near the water shore. The water levels of Main and Rodach were significantly higher during the time of early seed dispersal than during late seed dispersal which caused significant differences in spatial distribution of seedlings of early and late dispersers along the relief gradient. Early dispersers occurred in higher altitudes and farther from the water shore than late dispersers. Thereby, time of seed dispersal and distribution by wind and water in combination with water level fluctuations result in different spatial distribution patterns of the two dispersal groups. This could reduce interspecific competition, ensuring establishment of seedlings on a preferably large area and thus, explain the maintenance of diversity of Salix species in alluvial habitats.
- Published
- 2008
13. Floral Reward, Advertisement and Attractiveness to Honey Bees in Dioecious Salix caprea
- Author
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Dötterl, Stefan, primary, Glück, Ulrike, additional, Jürgens, Andreas, additional, Woodring, Joseph, additional, and Aas, Gregor, additional
- Published
- 2014
- Full Text
- View/download PDF
14. Einfluss der Phänologie der Samenausbreitung und des Wasserstandes auf die Etablierung von Keimlingen verschiedener Salix-Arten an renaturierten Auenstandorten
- Author
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Kehl, Alexandra, Reuter, Andreas, Aas, Gregor, Kehl, Alexandra, Reuter, Andreas, and Aas, Gregor
- Abstract
Weiden (Salix spp., Salicaceae) gehören zu den typischen Gehölzarten der Flussauen in Mitteleuropa. Viele Arten dieser Gattung haben ähnliche Eigenschaften (life history traits) und Strategien bei der Besiedelung frisch entstandener Rohböden. In Auenhabitaten kommen deshalb häufig mehrere Weidenarten gemeinsam vor und treten deshalb miteinander in Konkurrenz. In der vorliegenden Arbeit wurde untersucht, ob interspezifische phänologische Unterschiede in der Zeit der Samenausbreitung in Verbindung mit wechselnden Pegelständen des Flusses dazu führen, dass sich koexistierende Weidenarten räumlich differenziert ansiedeln und so die interspezifische Konkurrenz zwischen den Weiden reduziert wird. Auf frisch sedimentierten Auenböden an der Rodach und am Oberlauf des Mains (Oberfranken, Nordostbayern) wurde der Einfluss der Zeit des Samenfluges und der Schwankung der Pegelstände auf die räumliche Verteilung der Keimlinge von Salix fragilis s.l., S. purpurea, S. triandra und S. viminalis auf zwei Aufnahmeflächen untersucht. Ergänzt wurden diese Freilandstudien durch Untersuchungen zur Keimfähigkeit von Samen dieser Arten unter verschiedenen Bedingungen im Labor. Die Keimfähigkeit der Samen betrug unmittelbar nach ihrer Reife mindestens 80-100%. Bei trockener Lagerung (20 °C) erlosch die Keimfähigkeit von S. fragilis und S. triandra nach 4 Wochen, bei S. purpurea und S. viminalis nach spätestens 6 Wochen. Die Samen aller Arten können auch im Wasser keimen. Anhand des Zeitraumes der Samenausbreitung lassen sich die im Freiland untersuchten Weiden in eine früh (S. purpurea und S. viminalis) und in eine spät fruktifizierende Gruppe (S. fragilis s.l. und S. triandra) unterscheiden. Die Keimlinge aller Arten traten jeweils nur in einem schmalen Saum entlang des Ufers auf. Die Pegel von Main und Rodach an den Untersuchungsflächen waren während des Samenfluges der früh fruktifizierenden Gruppe höher als während des Samenfluges der spät fruktifizierenden Gruppe. Keimlinge beider Grup, Willows (Salix spp.) belong to the typical woody vegetation in alluvial habitats in Central Europe. Many species exhibit similar life history traits and strategies to colonize bare soil. Therefore, several willow species occur in alluvial habitats, and interspecific competition may become important. In this study, we investigated the relevance of the interspecific variation of seed distribution phenology in combination with water level fluctuations for a spatial differentiation of the coexisting species which may lead to a reduction of interspecific competition. We investigated the spatial distribution of willow seedlings of the species Salix fragilis s.l., S. purpurea, S. triandra and S. viminalis and its dependence of seed dispersal time and fluctuations of water level in the years 2000 and 2001 on two sample plots at the rivers Rodach and Main (Germany, Bavaria, Upper Franconia). Additional investigations on germination characteristics of different species revealed that germination rates were at least 80% immediately after seed ripening, but seed viability decreased very rapidly under warm, dry storage conditions. Salix fragilis s.l. and S. triandra lost their germination ability completely after 4 weeks, S. purpurea and S. viminalis after 6 weeks. Germination was also possible while seeds were floating in water. According to seed dispersal time, the species can be divided into early dispersers (S. viminalis, S. purpurea)and late dispersers (S. fragilis s.l., S. triandra). All seedlings occurred only in a narrow zone parallel to and near the water shore. The water levels of Main and Rodach were significantly higher during the time of early seed dispersal than during late seed dispersal which caused significant differences in spatial distribution of seedlings of early and late dispersers along the relief gradient. Early dispersers occurred in higher altitudes and farther from the water shore than late dispersers. Thereby, time of seed dispersal and distribution by
- Published
- 2008
15. Marri, Mallee, Mulga: Pflanzenvielfalt Westaustraliens
- Author
-
Lauerer, Marianne, primary, Nicolle, Dean, additional, French, Malcolm, additional, Börner, Annett, additional, Aas, Gregor, additional, and Schulze, Ernst-Detlef, additional
- Published
- 2011
- Full Text
- View/download PDF
16. Wald mit zwei Gesichtern. Pazifischer Trockenwald in Nordwest-Peru
- Author
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Lauerer, Marianne, primary, Horna, Viviana, additional, Zimmermann, Reiner, additional, Vásquez, Pedro, additional, and Aas, Gregor, additional
- Published
- 2008
- Full Text
- View/download PDF
17. Floral Reward, Advertisement and Attractiveness to Honey Bees in Dioecious Salix caprea.
- Author
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Dötterl, Stefan, Glück, Ulrike, Jürgens, Andreas, Woodring, Joseph, and Aas, Gregor
- Subjects
DIOECIOUS plants ,POLLINATORS ,HONEYBEE behavior ,PLANT reproduction ,SEXUAL selection in plants ,SPECTROPHOTOMETRY ,INFLORESCENCES - Abstract
In dioecious, zoophilous plants potential pollinators have to be attracted to both sexes and switch between individuals of both sexes for pollination to occur. It often has been suggested that males and females require different numbers of visits for maximum reproductive success because male fertility is more likely limited by access to mates, whereas female fertility is rather limited by resource availability. According to sexual selection theory, males therefore should invest more in pollinator attraction (advertisement, reward) than females. However, our knowledge on the sex specific investment in floral rewards and advertisement, and its effects on pollinator behaviour is limited. Here, we use an approach that includes chemical, spectrophotometric, and behavioural studies i) to elucidate differences in floral nectar reward and advertisement (visual, olfactory cues) in dioecious sallow, Salix caprea, ii) to determine the relative importance of visual and olfactory floral cues in attracting honey bee pollinators, and iii) to test for differential attractiveness of female and male inflorescence cues to honey bees. Nectar amount and sugar concentration are comparable, but sugar composition varies between the sexes. Olfactory sallow cues are more attractive to honey bees than visual cues; however, a combination of both cues elicits the strongest behavioural responses in bees. Male flowers are due to the yellow pollen more colourful and emit a higher amount of scent than females. Honey bees prefer the visual but not the olfactory display of males over those of females. In all, the data of our multifaceted study are consistent with the sexual selection theory and provide novel insights on how the model organism honey bee uses visual and olfactory floral cues for locating host plants. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
18. Floral Reward, Advertisement and Attractiveness to Honey Bees in Dioecious Salix caprea.
- Author
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Dötterl, Stefan, Glück, Ulrike, Jürgens, Andreas, Woodring, Joseph, and Aas, Gregor
- Subjects
- *
DIOECIOUS plants , *POLLINATORS , *HONEYBEE behavior , *PLANT reproduction , *SEXUAL selection in plants , *SPECTROPHOTOMETRY , *INFLORESCENCES - Abstract
In dioecious, zoophilous plants potential pollinators have to be attracted to both sexes and switch between individuals of both sexes for pollination to occur. It often has been suggested that males and females require different numbers of visits for maximum reproductive success because male fertility is more likely limited by access to mates, whereas female fertility is rather limited by resource availability. According to sexual selection theory, males therefore should invest more in pollinator attraction (advertisement, reward) than females. However, our knowledge on the sex specific investment in floral rewards and advertisement, and its effects on pollinator behaviour is limited. Here, we use an approach that includes chemical, spectrophotometric, and behavioural studies i) to elucidate differences in floral nectar reward and advertisement (visual, olfactory cues) in dioecious sallow, Salix caprea, ii) to determine the relative importance of visual and olfactory floral cues in attracting honey bee pollinators, and iii) to test for differential attractiveness of female and male inflorescence cues to honey bees. Nectar amount and sugar concentration are comparable, but sugar composition varies between the sexes. Olfactory sallow cues are more attractive to honey bees than visual cues; however, a combination of both cues elicits the strongest behavioural responses in bees. Male flowers are due to the yellow pollen more colourful and emit a higher amount of scent than females. Honey bees prefer the visual but not the olfactory display of males over those of females. In all, the data of our multifaceted study are consistent with the sexual selection theory and provide novel insights on how the model organism honey bee uses visual and olfactory floral cues for locating host plants. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
19. Birnennamen Aus Hemşin: Vorarbeiten zur Feststellung und Beschreibung der Birnenarten und ihrer regionalen Namen im östlichen Schwarzmeergebiet.
- Author
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Bläsing, Uwe
- Subjects
ARMENIAN names - Abstract
The article discusses a number of dialectal names for pears, which I collected in the Hamshen area of the Eastern Pontic range in Turkey. This study is the first attempt to give the etymology of these terms and to also describe the kind of pears meant by the respective names. As it is to be expected for Hamshen, which in former times was almost exclusively inhabited by an Armenian population, a great many of the pear names have a direct Armenian background. Others are of Pontic Greek origin, and a third group is represented by typical Turkish formations. The investigation showed that it was not possible to elucidate these names without considering the aspects of areal lingustics and cultural relationships. Irrespective of the language we can often observe several common patterns and motives in the formation of these terms. Thus, in addition to the 32 terms collected in Hamshen, many names taken from other languages of the area had to be included into the discussion. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
20. Encyclopedia of Woody Plants (Enzyklopädie der Holzgewächse: Handbuch und Atlas der Dendrologie).
- Author
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Stoehr, Michael
- Subjects
WOODY plants ,NONFICTION - Abstract
The article reviews the book "Encyclopedia of Woody Plants: Handbook and Atlas of Dendrology (Enzyklopädie der Holzgewächse: Handbuch und Atlas der Dendrologie)," edited by Peter Schütt, Hans J. Schuck, Gregor Aas, and Ulla M. Lang.
- Published
- 1996
- Full Text
- View/download PDF
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