10 results on '"LORANGER, HANNAH"'
Search Results
2. Invertebrate herbivory increases along an experimental gradient of grassland plant diversity
- Author
-
Loranger, Hannah, Weisser, Wolfgang W., Ebeling, Anne, Eggers, Till, De Luca, Enrica, Loranger, Jessy, Roscher, Christiane, and Meyer, Sebastian T.
- Published
- 2014
- Full Text
- View/download PDF
3. Competitor or facilitator? The ambiguous role of alpine grassland for the early establishment of tree seedlings at treeline
- Author
-
Loranger, Hannah, Zotz, Gerhard, and Bader, Maaike Y.
- Published
- 2017
- Full Text
- View/download PDF
4. Predicting invertebrate herbivory from plant traits: Polycultures show strong nonadditive effects
- Author
-
Loranger, Jessy, Meyer, Sebastian T., Shipley, Bill, Kattge, Jens, Loranger, Hannah, Roscher, Christiane, Wirth, Christian, and Weisser, Wolfgang W.
- Published
- 2013
5. Predicting invertebrate herbivory from plant traits: evidence from 51 grassland species in experimental monocultures
- Author
-
Loranger, Jessy, Meyer, Sebastian T., Shipley, Bill, Kattge, Jens, Loranger, Hannah, Roscher, Christiane, and Weisser, Wolfgang W.
- Published
- 2012
6. Effects of biodiversity strengthen over time as ecosystem functioning declines at low and increases at high biodiversity
- Author
-
Meyer, Sebastian T., Ebeling, Anne, Eisenhauer, Nico, Hertzog, Lionel, Hillebrand, Helmut, Milcu, Alexandru, Pompe, Sven, Abbas, Maike, Bessler, Holger, Buchmann, Nina, De Luca, Enrica, Engels, Christof, Fischer, Markus, Gleixner, Gerd, Hudewenz, Anika, Klein, Alexandra-Maria, de Kroon, Hans, Leimer, Sophia, Loranger, Hannah, Mommer, Liesje, Oelmann, Yvonne, Ravenek, Janneke M., Roscher, Christiane, Rottstock, Tanja, Scherber, Dr. Christoph, Scherer-Lorenzen, Michael, Scheu, Stefan, Schmid, Bernhard, Schulze, Ernst-Detlef, Staudler, Andrea, Strecker, Tanja, Temperton, Victoria Martine, Tscharntke, Teja, Vogel, Anja, Voigt, Winfried, Weigelt, Alexandra, Wilcke, Wolfgang, and Weisser, Wolfgang W.
- Subjects
Temporal effects ,Biodiversity ecosystem functioning (BEF) ,Ecosystem processes ,Grassland ,Mechanism ,Plant productivity ,Plant species richness ,Trophic interactions ,mechanism ,580 Plants (Botany) ,Biodiversity ecosystem functioning (bef) ,Ecosystems Research ,lcsh:QH540-549.5 ,plant species richness ,lcsh:Ecology ,grassland ,plant productivity ,Institut für Biochemie und Biologie ,biodiversity ecosystem functioning (BEF) ,ecosystem processes - Abstract
Human-caused declines in biodiversity have stimulated intensive research on the consequences of biodiversity loss for ecosystem services and policy initiatives to preserve the functioning of ecosystems. Short-term biodiversity experiments have documented positive effects of plant species richness on many ecosystem functions, and longer-term studies indicate, for some ecosystem functions, that biodiversity effects can become stronger over time. Theoretically, a biodiversity effect can strengthen over time by an increasing performance of high-diversity communities, by a decreasing performance of low-diversity communities, or a combination of both processes. Which of these two mechanisms prevail, and whether the increase in the biodiversity effect over time is a general property of many functions remains currently unclear. These questions are an important knowledge gap as a continuing decline in the performance of low-diversity communities would indicate an ecosystem-service debt resulting from delayed effects of species loss on ecosystem functioning. Conversely, an increased performance of high-diversity communities over time would indicate that the benefits of biodiversity are generally underestimated in short-term studies.Analyzing 50 ecosystem variables over 11 years in the world’s largest grassland biodiversity experiment, we show that overall plant diversity effects strengthened over time. Strengthening biodiversity effects were independent of the considered compartment (above- or belowground), organizational level (ecosystem variables associated with the abiotic habitat, primary producers, or higher trophic levels such as herbivores and pollinators), and variable type (measurements of pools or rates). We found evidence that biodiversity effects strengthened because of both a progressive decrease in functioning in species-poor and a progressive increase in functioning in species-rich communities. Our findings provide evidence that negative feedback effects at low biodiversity are as important for biodiversity effects as complementarityamong species at high biodiversity. Finally, our results indicate that a current loss of species will result in a future impairment of ecosystem functioning, potentially decades beyond the moment of species extinction. Human-caused declines in biodiversity have stimulated intensive research on the consequences of biodiversity loss for ecosystem services and policy initiatives to preserve the functioning of ecosystems. Short-term biodiversity experiments have documented positive effects of plant species richness on many ecosystem functions, and longer-term studies indicate, for some ecosystem functions, that biodiversity effects can become stronger over time. Theoretically, a biodiversity effect can strengthen over time by an increasing performance of high-diversity communities, by a decreasing performance of low-diversity communities, or a combination of both processes. Which of these two mechanisms prevail, and whether the increase in the biodiversity effect over time is a general property of many functions remains currently unclear. These questions are an important knowledge gap as a continuing decline in the performance of low-diversity communities would indicate an ecosystem-service debt resulting from delayed effects of species loss on ecosystem functioning. Conversely, an increased performance of high-diversity communities over time would indicate that the benefits of biodiversity are generally underestimated in short-term studies. Analyzing 50 ecosystem variables over 11 years in the world's largest grassland biodiversity experiment, we show that overall plant diversity effects strengthened over time. Strengthening biodiversity effects were independent of the considered compartment (above- or belowground), organizational level (ecosystem variables associated with the abiotic habitat, primary producers, or higher trophic levels such as herbivores and pollinators), and variable type (measurements of pools or rates). We found evidence that biodiversity effects strengthened because of both a progressive decrease in functioning in species-poor and a progressive increase in functioning in species-rich communities. Our findings provide evidence that negative feedback effects at low biodiversity are as important for biodiversity effects as complementarity among species at high biodiversity. Finally, our results indicate that a current loss of species will result in a future impairment of ecosystem functioning, potentially decades beyond the moment of species extinction.
- Published
- 2016
7. Effects of biodiversity strengthen over time as ecosystem functioning declines at low and increases at high biodiversity
- Author
-
Meyer, Sebastian T, Ebeling, Anne, Eisenhauer, Nico, Hertzog, Lionel, Hillebrand, Helmut, Milcu, Alexandru, Pompe, Sven, Abbas, Maike, Bessler, Holger, Buchmann, Nina, De Luca, Enrica, Engels, Christof, Fischer, Markus, Gleixner, Gerd, Hudewenz, Anika, Klein, Alexandra-Maria, de Kroon, Hans, Leimer, Sophia, Loranger, Hannah, Mommer, Liesje, Oelmann, Yvonne, Ravenek, Janneke M, Roscher, Christiane, Rottstock, Tanja, Scherber, Christoph, Scherer-Lorenzen, Michael, Scheu, Stefan, Schmid, Bernhard, Schulze, Ernst-Detlef, Staudler, Andrea, Weisser, Wolfgang W, et al, and University of Zurich
- Subjects
10127 Institute of Evolutionary Biology and Environmental Studies ,1105 Ecology, Evolution, Behavior and Systematics ,570 Life sciences ,biology ,590 Animals (Zoology) ,2303 Ecology - Published
- 2016
8. Responses of Tree Seedlings near the Alpine Treeline to Delayed Snowmelt and Reduced Sky Exposure.
- Author
-
Bader, Maaike Y., Loranger, Hannah, Zotz, Gerhard, and Mendieta-Leiva, Glenda
- Subjects
SNOWMELT ,TREE seedlings ,EUROPEAN larch ,TIMBERLINE ,SPRING plants - Abstract
Earlier snowmelt changes spring stress exposure and growing-season length, possibly causing shifts in plant species dominance. If such shifts involve trees, this may lead to changes in treeline position. We hypothesized that earlier snowmelt would negatively affect the performance of tree seedlings near the treeline due to higher spring stress levels, but less so if seedlings were protected from the main stress factors of night frosts and excess solar radiation. We exposed seedlings of five European treeline tree species: Larix decidua, Picea abies, Pinus cembra, Pinus uncinata, and Sorbus aucuparia to two snow-cover treatments (early and late melting, with about two weeks difference) combined with reduced sky exposure during the day (shading) or night (night warming), repeated in two years, at a site about 200 m below the regional treeline elevation. Physiological stress levels (as indicated by lower Fv/Fm) in the first weeks after emergence from snow were higher in early-emerging seedlings. As expected, shade reduced stress, but contrary to expectation, night warming did not. However, early- and late-emerging seedlings did not differ overall in their growth or survival, and the interaction with shading was inconsistent between years. Overall, shading had the strongest effect, decreasing stress levels and mortality (in the early-emerging seedlings only), but also growth. A two-week difference in snow-cover duration did not strongly affect the seedlings, although even smaller differences have been shown to affect productivity in alpine and arctic tundra vegetation. Still, snowmelt timing cannot be discarded as important for regeneration in subalpine conditions, because (1) it is likely more critical in very snow-rich or snow-poor mountains or landscape positions; and (2) it can change (sub)alpine vegetation phenology and productivity, thereby affecting plant interactions, an aspect that should be considered in future studies. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
9. Effects of biodiversity strengthen over time as ecosystem functioning declines at low and increases at high biodiversity
- Author
-
Oelmann, Yvonne, Roscher, Christiane, Hudewenz, Anika, Abbas, Maike, Temperton, Vicky, Weisser, Wolfgang W., Leimer, Sophia, Schmid, Bernhard, Schulze, Ernst-Detlef, Tscharntke, Teja, De Luca, Enrica, Gleixner, Gerd, Loranger, Hannah, Scherber, Christoph, Ravenek, Janneke M., Weigelt, Alexandra, Strecker, Tanja, Meyer, Sebastian T., Rottstock, Tanja, Vogel, Anja, Klein, Alexandra-Maria, De Kroon, Hans, Milcu, Alexandru, Fischer, Markus, Ebeling, Anne, Staudler, Andrea, Eisenhauer, Nico, Bessler, Holger, Scherer-Lorenzen, Michael, Scheu, Stefan, Hillebrand, Helmut, Wilcke, Wolfgang, Hertzog, Lionel, Voigt, Winfried, Buchmann, Nina, Pompe, Sven, Mommer, Liesje, and Engels, Christof
- Subjects
2. Zero hunger ,13. Climate action ,15. Life on land ,580 Plants (Botany) - Abstract
Human-caused declines in biodiversity have stimulated intensive research on the consequences of biodiversity loss for ecosystem services and policy initiatives to preserve the functioning of ecosystems. Short-term biodiversity experiments have documented positive effects of plant species richness on many ecosystem functions, and longer-term studies indicate, for some ecosystem functions, that biodiversity effects can become stronger over time. Theoretically, a biodiversity effect can strengthen over time by an increasing performance of high-diversity communities, by a decreasing performance of low-diversity communities, or a combination of both processes. Which of these two mechanisms prevail, and whether the increase in the biodiversity effect over time is a general property of many functions remains currently unclear. These questions are an important knowledge gap as a continuing decline in the performance of low-diversity communities would indicate an ecosystem-service debt resulting from delayed effects of species loss on ecosystem functioning. Conversely, an increased performance of high-diversity communities over time would indicate that the benefits of biodiversity are generally underestimated in short-term studies. Analyzing 50 ecosystem variables over 11 years in the world's largest grassland biodiversity experiment, we show that overall plant diversity effects strengthened over time. Strengthening biodiversity effects were independent of the considered compartment (above- or belowground), organizational level (ecosystem variables associated with the abiotic habitat, primary producers, or higher trophic levels such as herbivores and pollinators), and variable type (measurements of pools or rates). We found evidence that biodiversity effects strengthened because of both a progressive decrease in functioning in species-poor and a progressive increase in functioning in species-rich communities. Our findings provide evidence that negative feedback effects at low biodiversity are as important for biodiversity effects as complementarity among species at high biodiversity. Finally, our results indicate that a current loss of species will result in a future impairment of ecosystem functioning, potentially decades beyond the moment of species extinction.
10. Early establishment of trees at the alpine treeline: idiosyncratic species responses to temperature-moisture interactions.
- Author
-
Loranger H, Zotz G, and Bader MY
- Abstract
On a global scale, temperature is the main determinant of arctic and alpine treeline position. However on a local scale, treeline form and position vary considerably due to other climatic factors, tree species ecology and life-stage-dependent responses. For treelines to advance poleward or uphill, the first steps are germination and seedling establishment. These earliest life stages may be major bottlenecks for treeline tree populations and will depend differently on climatic conditions than adult trees. We investigated the effect of soil temperature and moisture on germination and early seedling survival in a field experiment in the French Alps near the local treeline (2100 m a.s.l.) using passive temperature manipulations and two watering regimes. Five European treeline tree species were studied: Larix decidua, Picea abies, Pinus cembra, Pinus uncinata and Sorbus aucuparia In addition, we monitored the germination response of three of these species to low temperatures under controlled conditions in growth chambers. The early establishment of these trees at the alpine treeline was limited either by temperature or by moisture, the sensitivity to one factor often depending on the intensity of the other. The results showed that the relative importance of the two factors and the direction of the effects are highly species-specific, while both factors tend to have consistent effects on both germination and early seedling survival within each species. We show that temperature and water availability are both important contributors to establishment patterns of treeline trees and hence to species-specific forms and positions of alpine treelines. The observed idiosyncratic species responses highlight the need for studies including several species and life-stages to create predictive power concerning future treeline dynamics., (© The Authors 2016. Published by Oxford University Press on behalf of the Annals of Botany Company.)
- Published
- 2016
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.