The Jena Experiment (DFG Forschergruppe)

Exploring Mechanisms Underlying the Relationship Between Biodiversity and Ecosystem Functioning (with W. Weisser, AM Klein and others)

Plant-insect interactions, flower traits, and pollination along an experimental plant diversity gradient

PhD student: Christine Venjakob (2010-2013)

  

Past research (2003-2010) has focused on multitrophic responses as a function of plant species richness. From 2010 onward, we study plant-pollinator interactions in a newly funded DFG Forschergruppe on mechanisms of biodiversity and ecosystem functioning.

Objectives:

1. Measurement of chemical flower traits to explain the diversity and frequency of flower visits along a plant diversity gradient
2. Assessment of the stoichiometry of mutualistic pollinator-flower interactions, comparing C:N:P ratios of pollinators with the reproduction success of pollinators
3. Construction of flower visitation and plant-pollinator interaction
4. Study plant species-specific responses to pollination and plant reproduction
5. Identification of breeding systems using hand- versus bagged pollination treatments in the greenhouse

The Jena Experiment is a multidisciplinary, long-term research facility to study the effects of changes in plant species richness on ecosystem processes. For example, we are interested in the effects of plant species richness on processes at higher trophic levels. One central research question during the last years has been: Are plant monocultures more susceptible to herbivore attack than plant mixtures? 

Selected publications

Bottom-up effects of plant diversity on multitrophic interactions in a biodiversity experiment  

published online 27th October 2010; see also Supplementary material S1 and S2

by Scherber C, Nico Eisenhauer, Wolfgang W. Weisser, Bernhard Schmid, Winfried Voigt, Markus Fischer, Ernst-Detlef Schulze, Christiane Roscher, Alexandra Weigelt, Eric Allan, Holger Beßler, Michael Bonkowski, Nina Buchmann, François Buscot, Lars W. Clement, Anne Ebeling,  Christof Engels, Stefan Halle, Ilona Kertscher, Alexandra-Maria Klein, Robert Koller, Stephan König, Esther Kowalski, Volker Kummer, Annely Kuu, Markus Lange, Dirk Lauterbach, Cornelius Middelhoff, Varvara D. Migunova, Alexandru Milcu, Ramona Müller, Stephan Partsch, Jana S. Petermann, Carsten Renker,  Tanja Rottstock, Alexander Sabais,  Stefan Scheu,  Jens Schumacher, Vicky M. Temperton & Teja Tscharntke (2010)

Nature 468, 553–556 (25 November 2010) (published online 27th October 2010), DOI: dx.doi.org/10.1038/nature09492

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Functional identity versus species richness: herbivory resistance in plant communities

by Scherber C, Heimann J, Köhler G, Mitschunas N, Weisser WW (2010)

Oecologia (online first), DOI: http://dx.doi.org/10.1007/s00442-010-1625-1 © Springer (Open Access by institutional agreement)

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Biodiversity and belowground interactions mediate community invasion resistance against a tall herb invader

by Scherber C, Mwangi PN, Schmitz M, Scherer-Lorenzen M, Beßler H, Eisenhauer N, Migunova VD, Weisser WW, Schulze ED, Schmid B (2010)

Journal of Plant Ecology 3 (2): 99-108, DOI: http://dx.doi.org/10.1093/jpe/rtq003 © Oxford Journals

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Diversity and beyond: Plant functional identity determines herbivore performance

by Specht J, Scherber C, Koehler G, Weisser WW (2008)

Journal of Animal Ecology 77, 1047–1055, DOI: http://dx.doi.org/10.1111/j.1365-2656.2008.01395.x

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The effects of plant diversity and insect herbivory on performance of individual plant species in experimental grassland

by Scherber C, Milcu A, Partsch S, Scheu S, Weisser, WW (2006)

Journal of Ecology 94, pp. 922-931, Blackwell Publishing, Oxford, DOI: http://dx.doi.org/10.1111/j.1365-2745.2006.01144.x

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Effects of plant diversity on invertebrate herbivory in experimental grassland

by Scherber C, Mwangi PN, Temperton VM, Roscher C, Schumacher J, Schmid B, Weisser WW (2006)

Oecologia 147, pp. 489-500, Springer Berlin, Heidelberg, New York. DOI: http://dx.doi.org/10.1007/s00442-005-0281-3

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For additional information, see the Jena Experiment homepage.

Cluster of Excellence "Functional Biodiversity research"

Grassland Management and biodiversity

PhD student: Georg Everwand (2010-2013); BSc students: Melanie Wiechmann, Annabelle Rohlfing

Agricultural intensification is known to greatly influence biodiversity and multitrophic interactions, but the relative contribution of plant functional groups, e.g. herbs and grasses, to biodiversity is less understood. In a multidisciplinary approach with botanists, soil ecologists and phytopathologists, we characterize insect responses to fertilization, mowing and plant functional group composition in a grassland experiment. Management and plant community effects will be characterized by insect samples, quantification of herbivory and experimental phytometer studies, addressing responses of pollinators, herbivores and predators.

Image Copyrights: left: (C) C. Scherber; right: (C) D. Gladbach

DFG-Research Training Group 1644 "Scaling Problems in Statistics"

PhD students: Urs Kormann (2010-2013), Tatiane Beduschi (2010-2013)

In a new DFG-funded Research Training Group (Graduiertenkolleg 1644), we study Scaling Problems in Statistics.

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Latest publication:

Scale effects in biodiversity and biological control: methods and statistical analysis

by Scherber C, Lavandero B, Meyer KM, Perovic D, Visser U, Wiegand K, Tscharntke T (2012).

Book Chapter in: Biodiversity and Insect Pests: Key Issues for Sustainable Management, First Edition. Edited by Geoff M. Gurr, Steve D. Wratten, William E. Snyder, Donna M.Y. Read. © 2012 John Wiley & Sons, Ltd. Published 2012 by John Wiley & Sons, Ltd. (in press).

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We focus on two major questions:

(1) Scale dependence of plant-insect interactions and community structure in changing landscapes

Spatial processes play an important role in community and population ecology. For example, the immigration of individuals from different habitats in the surrounding landscape can be important for local community composition, a process that is termed mass effect. In addition, community composition may change across different spatial scales. This can have far-reaching implications for ecosystem services. For example, the effects of local complexity on local pollinator communities may be both high or low, depending on spatial scale (scale- and context-dependence). While previous studies of our group have shown that landscape context is an important determinant of biodiversity and ecosystem services, mechanistic insights into the underlying processes are lacking. In particular, the data collected so far do not allow explicit spatial modelling approaches, spatial interpolation, or the incorporation of spatial dependencies. In addition, data on dispersal rates of organisms are lacking so far. Here, we will study the scale-dependence of ecological communities in agricultural landscapes and organism interactions in the field. The description and the prediction of the intensity of a species, i.e., the abundance of organisms, will be based on the theory of random marked sets, a generalization of the theory of marked point processes.

1.1. Effects of landscape complexity and spatial scale on organism interactions We will analyse dispersal, species richness, and abundance of focal organism groups using regular 1 × 1-ha grids positioned in 6 landscapes of different landscape complexity. At least 20 grid plots will be sampled per landscape. The identification of large quantities of invertebrates requires extensive expert support. GIS mapping and vegetation mapping will be central to explain the observed patterns and will serve as a basis for modelling. Vegetation leaf area index (LAI) and leaf nitrogen content will be predictors of vegetation density and attractiveness to herbivorous insects.

1.2. Dispersion of organisms in an agricultural landscape across different spatial scales We will model the relationship between organism mobility, spatial landscape configuration and immigration in new habitat (mass effects), including Monte Carlo simulations.

(2) Scale and context mediated conservation management in fragmented landscapes and populations

Given a finite total area that can be set aside for conservation in human-dominated landscapes, what configuration would represent the best strategy? In contrast to prevailing arguments in favour of large habitats based on the classic theory of island biogeography, many small islands spread over a larger region may better capture a maximum of biodiversity. A sample of many reserves over a wider geographic range maximizes species richness, but in each of these small fragments, persistence of populations and ecological interactions are reduced. Reducing dispersal among habitats is similar to reducing gene flow to keep a maximum of breed diversity. In both cases, dissimilarity (of local communities or breeding populations) is conserved and thereby beta-diversity is maximized. This is in contrast to common views that, in order to maximize diversity, functional connectivity between spatially separated subpopulations should be increased, as this reduces probabilities of subpopulation extinction or allele loss. The outcome of conservation strategies is not trivial, as it depends on properties of the landscape (spatial configuration of fragments, and type of landscape matrix), species, and the resulting communities (food web interactions and ecosystem functioning). A systematic analysis of existing studies will be most valuable.

In addition, a spatially explicit multi-species model with stochastic birth, death, and dispersal processes will be developed to analyse trade-offs between subpopulation persistence and beta-diversity for different landscape configurations and species groups. We will test the hypothesis that conservation value of population segregation and genetic exchange changes with fragmentation structure and scale.

We are interested in (i) developing a deeper theoretical understanding of the mechanisms using toy models and larger Monte Carlo studies; (ii) deriving optimal fragmentation strategies with respect to number and size of subpopulations and rate of geneflow between subunits that are relevant for animal conservation programs; (iii) field tests by repeated sampling (about 4) of several fragmentation levels (at least 10) in various landscapes (about 12), and model validation.

2.1. Conservation management in fragmented landscapes I An empirical test of the relative role of habitat area, fragmentation, and landscape matrix, using species differing in dispersal and specialisation has to be developed. Trapnesting bees and wasps, identified by extrenal experts, will serve as model systems to study fragmentation effects, supported by additional collections of organisms at different spatial scales.

2.2. Conservation management in fragmented landscapes II Development of spatially explicit models and analysis by means of Monte Carlo methods to clarify trade-offs in subpopulation persistence and beta-diversity.

2.3. Modelling of allele and haplotype dynamics in fragmented populations Here, theoretical optimisation of fragmentation patterns will be investigated. Genomic data of isolated chicken populations will be investigated.

4. Coexistence of species in populations with spatially structured interaction Analytical results on the parameter ranges will be obtained that allow for long term coexistence of species in interacting particle systems with different levels of local versus non-local competition.

 

DFG-GK 1086 Forest Biodiversity (Hainich National Park / UNESCO World Heritage site)

PhD students: Claudia Normann (2011-2014)

former PhD students: Elke Vockenhuber (2008-2011), Stephanie Sobek
former MSc student: Mareen Gollnow

In this project, we study plant-insect interactions in a tree diversity gradient in the Hainich National Park (Germany). The work includes a quantification of a diversity of interactions and field experiments with a main focus on herbs.

In the current project phase, we focus on the effects of distance to the forest edge and tree species richness on plant and insect biodiversity.

The explanatory variables are

a) distance to the forest edge and
b) low vs. high tree species richness,

laid out in a full factorial design along transects.

(all photographs by C. Scherber)

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Most recent publications

Tree diversity and environmental factors predict herb species richness and cover in Germany's largest connected deciduous forest

by Vockenhuber E, Scherber C, Seidel D, Langenbruch C, Meißner M, Tscharntke T (2011)

Perspectives in Plant Ecology, Evolution and Systematics 13:111-119 (published online 14th April 2011), DOI: dx.doi.org/10.1016/j.ppees.2011.02.004

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Tree diversity drives abundance and spatiotemporal β-diversity of true bugs (Heteroptera)

by Sobek S, Gossner M, Scherber C, Steffan-Dewenter I, Tscharntke T (2009)

Ecological Entomology 34, pp. 772 - 782. DOI: http://dx.doi.org/10.1111/j.1365-2311.2009.01132.x

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Canopy vs. understory: How does tree diversity affect trap-nesting bee and wasp communities and their natural enemies across forest strata?

by Sobek S, Tscharntke T, Scherber C, Schiele S & Steffan-Dewenter I (2009)

Forest Ecology and Management 258 (5), 609-615, DOI: http://dx.doi.org/10.1016/j.foreco.2009.04.026

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Spatiotemporal changes of beetle communities across a tree diversity gradient

by Sobek S, Steffan-Dewenter I, Scherber C & Tscharntke T (2009)

Diversity and Distributions 15 (4), pp.660 - 670, DOI: http://dx.doi.org/10.1111/j.1472-4642.2009.00570.x

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Sapling herbivory, invertebrate herbivores and predators across a natural tree diversity gradient in Germany´s largest connected deciduous forest

by Sobek S, Scherber C, Steffan-Dewenter I, Tscharntke T (2009)

Oecologia 160(2): 279-88, DOI: http://dx.doi.org/10.1007/s00442-009-1304-2 © Springer (Open Access by institutional agreement)

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Further project details can be found here.

Biodiversity Exploratories

PhD student: Christoph Rothenwöhrer (2008-2011)

 

The Biodiversity Exploratories are part of the international long-term ecological research (iLTER) network. In Germany, there are several such long-term ecological research projects. Within the framework of the Biodiversity Exploratories, we study ecosystem processes such as herbivory and pollination in selected grassland and woodland sites along land-use gradients.

General information about the Biodiversity Exploratories can be found here.

Project partners: Ingolf Steffan-Dewenter, Cathrin Westphal, Alexandra-Maria Klein, Jochen Krauss.

Associated PhD students: Michaela Bellach (Bayreuth), Juliane Steckel (Bayreuth)

CLIMAITE (Denmark)

Effects of climate change on above-belowground multitrophic interactions

PhD student (co-supervised): David Gladbach (2007-2010)

We are currently collaborating with CLIMAITE, which is a Danish research centre to investigate how climatic changes will affect biological processes in natural (heathland) ecosystems. Specifically, studies involve aboveground invertebrates and herbivory measurements.

Most recent publications

Stevnbak et al 2009

Further project details can be found here.

Peat Bog Ecosystems

Restoration of peatland and conservation of the Dwarf Birch (Betula nana)

MSc student: Barbara Mayer (2010)

Since May 2010, we are studying plant-herbivore interactions along a drought gradient in a peat bog in Southern Bavaria (close to the towns of Seeshaupt and Bernried). In particular, we study the performance of the dwarf birch, Betula nana L. (Betulaceae), which is a glacial relict species. We monitor bog water level and follow plant performance over time.

Some of Germany´s most extensive peat bog ecosystems occur throughout Southern Bavaria (Germany). These bogs are fascinating environments that have been formed gradually after the last glaciations (about 10,000 years before today). Situated at the foothills of the Alps, many of these peat bogs (locally called "Filz") belong to the most vulnerable ecosystems in Germany, inhabited by often highly adapted species that can cope with the low pH of soil and water. I am personally interested in dragonflies, butterflies and herbivorous insects inhabiting peat bogs, as well as carnivorous plants, grasses, sedges and rushes, and Sphagnum peat mosses.

 

(1) Eriophorum vaginatum in the "Murnauer Moos" (Southern Germany)
(2) Bog lake in a peat bog in Southern Bavaria (near Seeshaupt, Starnberger See)
(3) A leaf of the sundew, Drosera rotundifolia

Carnivorous Plants

Carnivorous Plants - please also see the book by Barthlott et al., for which I contributed some images of carnivorous plants.

Heliamphora tatei on Pico da Neblina (Brazilian-Venezuelan Border), 1998.

 

Narrow-leaved Ragwort (Senecio inaequidens)

Biological control and management of invasive alien plants

MSc student: Kerstin Albrecht (2011; University of Rostock)

Narrow-leaved ragwort is an invasive alien plant introduced to Europe with wool transports from South Africa about hundred years ago. It is currently rapidly spreading across Europe. In a research facility at Silwood Park (UK), we have installed an experiment on the effects of herbivory and competition on S. inaequidens. Although the main results of the establishment phase have been published, some plants have survived from 2002 until today and are still producing inflorescences even though growing in intact British grassland. It will be fascinating to see if and how this plant will survive and reproduce over long-term periods.

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Selected publications:

Scherber C., Crawley M.J., Porembski S. (2003) The effects of herbivory and competition on the invasive alien plant Senecio inaequidens (Asteraceae). Diversity and Distributions 9: 415-426, Blackwell Publishing, Oxford.

Scherber, C., Crawley M.J., Porembski S. (2004) Insect herbivory and plant competition studies on the invasive alien plant Senecio inaequidens (Asteraceae) under laboratory conditions. In: Kuehn, I. & Klotz, S. (eds.) Biological Invasions - Challenges for Science. Neobiota 3: 41-52, Berlin.

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The experiments conducted at Silwood Park (UK) in 2002 have also been documented in the Flora of Berkshire, written by Michael J. Crawley, FRS

Climatic change along an altitudinal gradient in the Harz mountains

Postdoctoral Guest Scientist (2009-2010): Germano Leão Demolin Leite

In collaboration with Germano Leão Demolin Leite, we are studying herbivory along an altitudinal gradient in the Harz mountains. The focal plant species is blueberry (Vaccinium myrtillus L.).

Agroforestry systems in Indonesia (with Y. Clough, P. Hoehn, J. Groeneveld and others)

I have been co-supervising MSc and PhD students and co-authoring a book chapter on tropical biodiversity.

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Selected publications:

Methane emissions from tank bromeliads in neotropical forests

by Martinson G, Werner FA, Scherber C, Conrad R, Corre MD, Flessa H, Wolf K, Klose M, Gradstein SR, Veldkamp E (2010)

Nature Geoscience (Published online 17 October 2010), DOI: http://dx.doi.org/10.1038/ngeo980

Related content:

 article: Biogeochemistry: Cryptic wetlands.
by Joseph B. Yavitt (2010), Nature Geoscience, DOI: dx.doi.org/doi:10.1038/ngeo999 (Published online 17 October 2010).

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Multifunctional shade-tree management in tropical agroforestry landscapes - a review

by Tscharntke T, Clough Y, Bhagwat S, Buchori D, Faust H, Hertel D, Hölscher D, Juhrbandt J, Kessler M, Perfecto, I, Scherber C, Schroth G, Veldkamp E, Wanger T (2011)

Journal of Applied Ecology 48:619–629, June 2011 ( published online 31.01.2011), DOI: dx.doi.org/10.1111/j.1365-2664.2010.01939.x

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In collaboration with other researchers, I have been involved in studies of tropical ecosystems, including the projects listed below.

Works on carnivorous plants (Heliamphora, Drosera) in the Amazon basin (Mt. Neblina, Brazil/Venezuela)

(with F. Rivadavia Lopez, A. Wistuba, J. Nerz and others)

Nerz, J. & Wistuba, A. (2000) Heliamphora hispida (Sarraceniaceae), a new species from Cerro Neblina, Brazil-Venezuela". Carnivorous Plant Newsletter Volume 29, Number 2, June 2000, pages 37 - 41.

 

Gallery forest and Inselbergs in the Ivory Coast (West Africa)

(with S. Porembski, N. Biedinger and others, University of Rostock; Image credits: S.Porembski)

This was a short-term research stay in 2000, where we collected plant material and did vegetation relevés on inselbergs in the Ivory Coast. Among other plant species, we found the carnivorous plant species Genlisea stapfii, Utricularia subulata, Utricularia juncea and Utricularia pubescens (Lentibulariaceae) and Drosera indica (Droseraceae).

 

Side Projects

(1) Sciencegarden

From 2001-2008 I was a freelance writer for the journal "sciencegarden", a German young scientists´ on-line journal which has won a German nationwide Science Journalism prize in 2006 (the "Heureka"-award by Sanofi-Aventis)

(2) BEAUTYCHECK

I have been involved in two side-projects, where I have been working together with psychologists on human facial attractiveness

(3) Public perception and genetically modified food

This study was part of a research competition for Young Scientists (Deutscher Studienpreis / German Students Award). More information can be found at www.studienpreis.de